JOS - European Journal of Oral Surgery

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JOS European journal of oral surgery

Official journal of the SocietĂ Italiana Specializzati in Chirurgia Odontostomatologica ed Orale

1 ISSUE 2 VOL.

September 2010

ISSN 2037-7525

CASA EDITRICE ARIESDUE

ITALIA PRESS EDIZIONI

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European journal of oral surgery Official journal of the SocietĂ Italiana Specializzati in Chirurgia Odontostomatologica ed Orale www.ejos.eu

European journal of oral surgery

Editor-in-chief

Publisher

Prof. Franco Santoro (Italy)

ARIESDUE SRL

ITALIA PRESS EDIZIONI

Via Airoldi, 11 22060 Carimate (CO) +39 (0)31.79.21.35 +39 (0)31.79.07.43 www.ariesdue.it info@ariesdue.it

Via Larga, 8 20122 Milano (MI) +39 (0)2 86.46.49.21 +39 (0)2 86.90.372 www.italiapressedizioni.it info@italiapressedizioni.it

Editorial Director Prof. Carlo Maiorana (Italy)

Associate Editor

ISSN: 2037-7525

Prof. Piero Balleri (Italy) Prof. Pascal Valentini (France)

Editorial Board Dr. Giovanni Battista Grossi (Italy) Prof. Alan Herford (USA) Prof. Fouad Khoury (Germany) Prof. Jaime A. Gil (Spain) Prof. Massimo Simion (Italy) Prof. Anton Sculean (Switzerland) Prof. Tiziano Testori (Italy) Prof. Leonardo Trombelli (Italy) Dr. Istvan Urban (Hungary)

DIRECTOR Dino Sergio Porro EDITORIAL STAFF Angela Battaglia: a.battaglia@ariesdue.it Cristina Calchera: farma@ariesdue.it Simona Marelli: doctoros@ariesdue.it MARKETING & ADVERTISING Barbara Bono: b.bono@ariesdue.it Paola Cappelletti: p.cappelletti@ariesdue.it Franco De Fazio: f.defazio@ariesdue.it WEB & GRAPHIC DESIGN Michele Moscatelli: grafica@ariesdue.it Simone Porro: simone@ariesdue.it Cover image courtesy of Mirko Marcon

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JOS VOL.1 N.2 2010

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European journal of oral surgery

Issue 2 Volume 1 September 2010

page 37

Decision making process for the implant-supported prosthetic rehabilitation of the atrophic posterior maxilla in partially edentulous patients

page 47

Smart-lift technique used in association with a hydroxyapatite-based biomaterial. Clinical outcomes and postoperative morbidity

page 56

Endodontic surgery: a critical review

35

JOS VOL.1 N.2 2010

OsseoSpeed TX ™

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Barewal RM, Stanford C. A randomized prospective clinical trial of the effect of three dental implant loading protocols on stability -an interim report.

Appl Osseointegration Res 2006;5:62-67.

Donati M, La Scala V, Billi M, Di Dino B, Torrisi P, Berglundh T. Immediate functional loading of implants in single tooth replacement: a prospective clinical multicenter study.

Clin Oral Implants Res 2008;19:740-48. (ID No. 79065)

• Risultati predicibili, anche per i casi compromessi, dove impianti con un’altra superficie sarebbero meno efficaci.

Galindo-Moreno P., Nilsson P., King P., Becktor J., Maiorana C. and Schramm A. Baseline data from a multi centre study replacing single anterior tooth with narrow, 3 mm diameter, OsseoSpeed™ implants.

Clin Oral Impl Res 2009;20(9):899

• Adatto per tutte le indicazioni di trattamento.

Geckili O, Bilhan H, Bilgin T. A 24-week prospective study comparing the stability of titanium dioxide grit-blasted dental implants with and without fluoride treatment.

Int J Oral Maxillofac Implants 2009;24(4):684-8

• Supporto biologico ottimizzato per inserimento immediato e protocolli di carico precoce.

• Disegnato e testato clinicamente per il mantenimento del livello dell’osso marginale (riduzione media di osso marginale di solo 0,3 mm dopo 5 anni).

Oxby G, Lindqvist J, Nilsson P. Early Loading of Astra Tech OsseoSpeed Implants Placed in Thin Alveolar Ridges and Fresh Extraction Sockets. Appl Osseointegration Res 2006;5:68-72. (ID no. 78735) Roediger M, Huels A, Schliephake H, McGlumphy E, Phillips K. Early loading of fluoride modified implants in the posterior mandible. J Dent Res 2009;84(Spec Iss A):3385

Stanford C, Johnson G, Fakhry A, Gartton D, Mellonig J, Wagner W. Outcomes of a Fluoride Modified Implant One Year After Loading in the Posterior-Maxilla when Placed with the Osteotome Surgical Technique.

Appl Osseointegration Res 2006;5:50-55.

Stanford C, Johnson G, Fakhry A, Aquilino S, Gratton D, Reinke M, et al. Three year post-loading outcomes with MicroThread OsseoSpeed dental implants placed in the posterior-maxilla.

Appl Osseointegration Res 2008;7:49-57 Steveling H, Mertens C, Merkle K. Bioactive implants: 5 years of experience with a fluoridized surface.

J Clin Periodontol 2009;36(Suppl 9):197 Toljanic JA, Baer RA, Ekstrand K, Thor A. Implant rehabilitation of the atrophic edentulous maxilla including immediate fixed provisional restoration without the use of bone grafting: a review of 1-year outcome data from a long-term prospective clinical trial.

Int J Oral Maxillofac Implants 2009;24(3):518-26.

Vroom MG, Sipos P, de Lange GL, Grundemann LJ, Timmerman MF, Loos BG, et al. Effect of surface topography of screw-shaped titanium implants in humans on clinical and radiographic parameters: a 12-year prospective study.

Clin Oral Implants Res 2009;20(11):1231-39

Schliephake H, Hüls A, Müller M. Early Loading of Surface Modified Titanium Implants in the Posterior Mandible -Preliminary Results. Appl Osseointegration Res 2006;5:56-58.

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European journal of oral surgery Official journal of the SocietĂ Italiana Specializzati in Chirurgia Odontostomatologica ed Orale

European journal of oral surgery

Editor-in-chief

Prof. Franco Santoro SISCOO President

Editorial Dear colleagues, I am pleased and proud to present you the second issue of JOS. From the opinions I gathered, it seems that the monograph with the two case reports was appreciated and considered appealing, practical and very educational from the clinical point of view.

This issue is released a few days before our first SISCOO Congress which is also the first official meeting of the Italian Society of Specialists in Dental Surgery: as you know the congress will be held every two years, and the the years inbetween the association will organize two events, namely courses on current topics.

As you may notice, the programme of this congress includes the lectures of some of the most renowned speakers in the fields of periodontology, piezosurgery, endodontic surgery and BRONJ treatment; all this is attuned with SISCOO’s ethos, aiming at clinical excellence and qualified clinical updating.

I wish to thank in particular general Samuele Valentino and his staff for the prestigious hospitality offered, as usual, open-heartedly and friendly.

I will wait for you on friday, September 24th.

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Monograph

Decision making process for the implant-supported prosthetic rehabilitation of the atrophic posterior maxilla in partially edentulous patients Ilaria Franchini* Matteo Deflorian* Maria Cristina Rossi* Matteo Capelli* Tiziano Testori**

* Galeazzi Orthopedic Institute, Dental Clinic – IRCCS –Department of Health Technologies University of Milan, Italy **Head of the Section of Implant Dentistry and Oral Rehabilitation Galeazzi Orthopedic Institute, Dental Clinic – IRCCS – Department of Health Technologies University of Milan, Italy

Background Loss of alveolar bone in the posterior maxilla and progressive pneumatization of the maxillary sinus following tooth extraction result in moderate to severe crestal bone atrophy thus influencing implant placement.

Surgical procedures like sinus lift surgery with lateral approach or sinus lift with crestal approach and the use of short implants are considered to be predictable techniques.

The clinical indication for the correct surgical technique and implantsupported prosthetic rehabilitation strongly depends on the individual anatomical situation and on the amount of residual crestal bone. The aim of this paper is to provide a precise diagnostic classification and decision making process, in order to determine the most appropriate procedure in the implant-supported prosthetic rehabilitation of the lateral-posterior maxillary edentulism.

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Key words: maxillary atrophy; maxillary sinus elevation; sinus grafting

floor

Monograph

Introduction In the implant-supported prosthetic rehabilitation of the lateral-posterior maxilla, unfavorable anatomical conditions are frequently observed. Posterior tooth loss and progressive pneumatization of the maxillary sinus result in crestal bone atrophy of different severity for each individual patient. The degree of crestal bone atrophy may influence implant placement when following a traditional protocol. Several clinical studies regarding surgical techniques for the treatment of complex cases have been published, and currently sinus lift techniques according to Caldwell-Luc modified by Tatum (1), sinus lift techniques with crestal approach (2) and the use of short implants (3) and tilted implants (4) are considered to be highly predictable procedures in long and medium term.

However, indications to the different surgical procedures are still not ultimately defined, due to the overlapping of different protocols in relation to the quantity of residual bone in the cranial-caudal direction.

The aim of this paper is to provide a precise diagnostic classification and decision making process, in order to determine the most appropriate procedure in the implant-supported prosthetic rehabilitation of the lateral-posterior maxillary edentulism.

Anatomical diagnosis Following tooth loss, the crestal bone undergoes a physiological remodeling processes. Schropp et al. (5) documented a horizontal resorption of the crestal bone of approximately 50% and an average decrease of the vertical height in the center of the crestal bone of approximately 1 mm in an interdental post-extraction site 12 months after a single tooth extraction.

Furthermore, periodontal disease, which is considered to be one of the main reasons of tooth loss, also increases alveolar bone loss.

The alveolar process of the posterior maxilla is adjacent to the maxillary sinus, which is in continuous expansion even in patients with healthy teeth. Tooth loss seems to further accelerate sinus pneumatization (6).

Bone loss in post-extraction sites of the posterior maxilla occurs mainly according to three primary vectors: the horizontal vestibular-palatal vector, the cranial vector and the caudal vector. The resulting volumetric variation of the edentulous bone crest modifies the three-dimensional relationships between the arches. As a result, implant rehabilitation of the posterior maxilla is extremely demanding in unfavorable anatomical conditions.

Remodeling of the alveolar process in post-extraction sites results in anatomical situations, which can be classified as follows, corresponding to increasing severity of the atrophy. › Adequate crestal bone thickness with almost maintained harmonic arch form and adequate interarch distance.

› Adequate crestal bone thickness with almost maintained harmonic arch form and increased interarch distance. › Inadequate crestal bone thickness with inverse interarch relationship and adequate inter-arch distance. › Inadequate crestal bone thickness with inverse interarch relationships and increased inter-arch distance.

When determining the therapeutic indication, it is of utmost importance to consider the type of edentulism, the quantity of residual bone tissue in the cranialcaudal as well as in the vestibule-palatal direction and the resulting relationship between upper and lower jaw.

Therapeutic alternatives In the last decade, scientific development in implant dentistry has determined highly improved clinical solutions aimed to treat compromised anatomical situations in the edentulous upper jaw.

Sinus lift with lateral and crestal approach, the use of short implants and the use of tilted implants inserted in pre- and post-sinusal position are the most reliable and predictable techniques (6, 7, 8, 9, 10).

Sinus lift with lateral approach The sinus lift technique with lateral approach is a welldocumented procedure in literature. Several studies report high implant survival rate in relation to the performed bone augmentation technique (7, 11).

The lateral approach to the maxillary sinus, performed according to Caldwell-Luc procedure modified by Tatum (1), require the elevation of a full-thickness flap following crestal or palatal incision in the residual keratinized gingival tissue. An oval-shaped antrostomy, is performed according to the mesio-distal extension of the maxillary sinus and the planned implant position. The presence of one or more Underwood septa may require two or more antrostomies, performed each mesially and distally to the septum.

The Schneiderian membrane is lifted first cranially, and subsequently mesially, distally and caudally, until the medial wall of the maxillary sinus is visible. The graft material is placed initially in the less accessible areas — anterior and posterior recess — and in contact with the bone walls, in order to obtain adequate blood supply, which is an essential condition for the succesful integration of the graft (Fig. 1a-c, Fig. 2a-g).

Several authors have evaluated the material recommended for maxillary sinus lift procedures: whether autogenous, alloplastic or xenogenous grafts, used either individually or combined. All materials show good graft integration and high survival rate of implants inserted in augmented sinus and subsequently functionally loaded loaded (12, 13, 14, 15).

The use of rough-surfaced implants (7, 11) and the placement of membranes on the antrostomy to protect the graft (16, 17) both show to further optimize implant survival rates.

The quantity of the residual alveolar bone is the critical factor when implant placement is performed simultaneously with bone augmentation procedure:

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A

B

C

FIG. 1

Sinus lift with lateral approach involves a generally oval-shaped antrostomy at the vestibular wall of the maxillary sinus and the elevation of the sinus membrane up to the lateral wall of the nose. Image courtesy of ACME Editore (from: Testori T, Wallace SS, Weinstein RL. La chirurgia del seno mascellare. ACME Editore 2005)

A

B

C

D

E

F

G

FIG. 2

Antrostomy of the maxillary vestibular wall and elevation of the sinus membrane allow insertion of the graft and successive implant placement.

Image courtesy of ACME Editore (from: Testori T, Wallace SS, Weinstein RL. La chirurgia del seno mascellare. ACME Editore 2005)

currently, 3 mm of residual crestal bone seem to be sufficient to provide primary implant stability (18, 19, 20, 21). Several publications report that different heights of residual crestal bone do not influence graft integration and implant survival in delayed implant placement procedures (19) (Fig. 3a-c).

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Monograph B

A

C

FIG. 3

Bilateral implant-prosthetic rehabilitation of edentulous ridge with height < 3 mm (a) by means of sinus lift with lateral approach (b) and delayed implant placement (c).

Sinus lift with crestal approach In order to reduce surgical trauma and post-operative complications associated with the lateral approach technique, Summers (2) suggested the maxillary sinus lift procedure with a crestal approach. This procedure combines osteotomy of the alveolar ridge, infraction of the sinus floor cortical bone and subsequent elevation of the Schneiderian membrane, using calibrated osteotomes, with graft material (Fig. 4a-g) (22, 23, 24).

Modifications of the crestal technique donâ&#x20AC;&#x2122;t seem to influence implant survival (25, 26). Even in this procedure, residual bone height is the critical factor

A

B

for the survival of inserted and functionally loaded implants: 4-6 mm height are considered to be sufficient to perform implant placement simultaneous to bone augmentation procedures with predictable results (8, 27, 28).

D

C

FIG. 4

E

Sinus lift with crestal approach involves initial preparation of the site up to the sinus floor (a), expansion by means of osteotomes (b), infraction of the sinus floor (c), elevation of the membrane with graft (d), and simultaneous implant F placement (e, f).

Radiographic evaluation after 24 months shows graft stability (g).

Image (a-d) courtesy of ACME Editore (from: Testori T, Wallace SS, Weinstein RL. La chirurgia del seno mascellare. ACME Editore 2005)

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Short implants (< 10 mm) From a biomechanical point of view, the significance of the crown / implant ratio has been revisited, since occlusal load has been showed to be substantially transferred to the bone in the coronal implant portion (29, 30).

The development of new implant macro- and microdesigns allowed to obtain high secondary stability and to shorten healing time, even in low-density bone and unfavorable biomechanical conditions (Fig. 5) (31, 32, 33). In addition, less traumatic surgical techniques have been developed to provide higher primary stability (32, 34, 35, 36).

Currently, implant rehabilitation supported by short implants is considered to be predictable treatment if the following prerequisites are fulfilled: › micro-rough implant surface(32, 34, 35, 36); › implant site under-preparation using minimal invasive surgical techniques, in order to achieve high primary implant stability, especially in low-density bone (9, 37, 38); › reduced occlusal tables of implant prosthesis in order to reduce the occlusal load (34, 39, 40, 41); › correct treatment planning including the evaluation of the correct home care procedure for the maintenance of the implant-supported prosthetic restoration, considering the decreased vestibulum depth and the modified crestal bone position (9, 34).

Pre- and post-sinusal tilted implants Maxillary sinus hyper-pneumatization is frequently associated with insufficient bone availability for implant insertion in the pre-maxilla and in the maxillary tuberosity. Several studies demonstrated that implant mesio-distal tilting to the occlusal plane does not have a negative influence on implant survival rate (10, 42, 43). The less invasive surgical approach involves the insertion of distally tilted implants parallel to the mesial wall of the maxillary sinus and mesially tilted implants in the maxillary tuberosity, exclusively in residual bone: this procedure allows to create mesial and distal posts for the implant-supported prosthetic rehabilitation with lower morbidity (Fig. 6a, b). For this reason, it is recommended in elderly patients and in subjects with severe systemic diseases or with maxillary sinus diseases, where more invasive and sophisticated surgery is not indicated.

Indication for the implant-supported prosthetic reahabilitation of atrophic posterior maxilla Remodeling of the posterior maxillary alveolar process leads to different degree of atrophy and anatomical situations, requiring different surgical approaches (Fig. 7, Tab. 1).

1. Type A: sinus pneumatization Unaltered threedimensional inter-arch relationship and harmonic arch form allow prosthetically-guided implant-prosthetic

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FIG. 5

Implant-prosthetic rehabilitation of the right lateralposterior maxilla with short implants (< 10mm) and splinted prosthetic crowns.

A

B

FIG. 6

Implant-prosthetic rehabilitation of the posterior maxilla with distally tilted pre-sinus implants (a) and distally tilted pre-sinus implant and mesially tilted post-sinus implant (b).

rehabilitation without appositional bone grafts. Soft tissue augmentation may improve aesthetic results.

Residual crestal bone height is the critical factor in the surgical therapeutic choice. › When residual bone height is less than 3 mm, it is insufficient in providing primary implant stability when simultaneously performed with sinus lift procedure, and needs to be augmented before implant placement. Therefore, the therapeutic indication includes sinus lift with lateral approach and delayed implant placement. › When residual bone height is 3 mm, it may be sufficient for implant stabilization. Implants can be

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Monograph

Type A Sinus pneumatization

Sinus lift with autograft.

Type B Transverse deficit

Sinus lift with graft and crestal expansion or vestibular onlay bone graft.

Type C Vertical deficit

Vertical onlay bone graft with or without sinus lift .

Type D Combined deficit

Vertical and transversal onlay bone graft with or without sinus lift.

FIG. 7

Remodeling of the posterior maxillary alveolar process leads to different anatomical situations, requiring different surgical approaches.

Image courtesy of ACME Editore (from: Testori T, Wallace SS, Weinstein RL. La chirurgia del seno mascellare. ACME Editore 2005)

Table 1

Decision making process for the correct implant-supported prosthetic therapeutic indication in the atrophic posterior maxilla with residual crestal bone height ≤ 6 mm. (h = crestal bone height, SL = sinus lift)

inserted at the same time as bone augmentation procedure. When implant primary stability is not adequate, a two-step surgical procedure is required. › Residual bone height between 4 and 6 mm allows a more conservative and less invasive approach. Sinus lift with crestal approach and simultaneous implant placement are indicated. › Residual bone height of at least 6 mm requires a classification in single and multiple edentulism (44).

The correct use of short implants results in high

survival rates (3, 9). The strategy of splinting short implants together in order to improve the correct distribution of functional load makes this treatment option not ideal in cases of single distal edentulism.

Although the crown / implant ratio was not found to have a significant influence on implant survival, in case of single edentulism it is preferable to choose asurgical protocol combining a sinus lift surgery with a crestal approach and simultaneous placement of longer implants (> 10 mm). In case of a single

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FIG. 8

Sinus lift with lateral approach and implant-supported prosthetic rehabilitation with longer crowns may compensate the vertical discrepancy.

FIG. 9

Sinus lift with lateral approach associated with bone augmentation techniques allows a correct and harmonic implant-supported prosthetic rehabilitation in case of increased inter-arch distance and reduced vestibular depth.

edentulous space, a short implant can be inserted in the residual bone, as adjacent teeth provide protection during occlusion. In case of multiple edentulous spaces, rehabilitation with short implants is highly recommended because of its high predictability, lower rate of complications and low morbidity compared to more invasive therapeutic techniques. These preliminary reccomandations derive from ongoing multicenter clinical trials of our department. More long term data are advisable before involving this procedures in clinical practice.

2. Type B: tansverse deficit Considerable resorption in the vestibular-palatal direction may result in an inverse relationship between the bone bases on the horizontal plane (Fig. 10). It is essential to assess the ideal position of the prosthetic crowns and their relationship with the crestal bone. Horizontal prosthetic compensation may lead to overextended crowns, resulting in difficult hygienic maintenance. Moreover, prosthetic compensation may create a horizontal cantilever, increasing lateral forces, especially in partial edentulism. Instead, cross-bite prosthetic rehabilitations show dramatic aesthetic limitations as well as functional consequences: invasion of the lingual area may cause difficulties in phonetics and unintentional cheek biting. In these cases it is essential to correct the skeletal relationship in the horizontal direction, with block grafts or horizontal GBR techniques associated with sinus lift with lateral approach. When the residual crestal bone height is 4 to 6 mm, the split-crest or horizontal bone augmentation can be performed.

3. Type C: vertical deficit Adequate crestal bone thickness with harmonic arch form but increased interarch distance are more complex, and the frequently associated decreased vestibulum depth further aggravate the clinical situation. â&#x20AC;ş When inter-arch distance is moderately increased and vestibulum depth is adequate, it is possible to realize an implant-prosthetic rehabilitation with longer prosthetic crowns, in order to compensate the vertical discrepancy (Fig. 8).

The surgical approach depends on the residual bone height. â&#x20AC;ş When inter-arch distance is severely increased and vestibulum depth is limited, prosthetic compensation

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FIG. 10

Tooth loss leads to crestal bone atrophy in the vestibularpalatal direction with opposite vectors, up to inversion of skeletal relationships on the horizontal plane. Image courtesy of ACME Editore (from: Testori T, Wallace SS, Weinstein RL. La chirurgia del seno mascellare. ACME Editore 2005)

is not possible, since extremely long prosthetic crowns do not correspond to an aesthetically acceptable and hygienically maintainable implantsupported prosthetic rehabilitation. The surgical approach has to restore favorable bone volume and skeletal relationships, in order to obtain a prosthetically-guided rehabilitation with long-term predictability. Three-dimensional alterations of the inter-arch relationship need to be corrected with GBR techniques or block grafts. Bone augmentation techniques can be associated with sinus lift with lateral approach, in order to further increase bone availability for longer implants (Fig. 9).

4. Type D: combined deficit Tooth loss due to severe periodontal disease, trauma, cystic or neo-plastic diseases contribute to extreme crestal atrophy with extremely compromised anatomical situations.

Frequently, the edentulous crestal bone in the posterior maxilla is severly deficient in the vestibularpalatal direction, leading to reverse maxillo-mandibular relationship on the horizontal plane, and in the cranio-caudal direction with significant increase of the vertical inter-arch distance.

Monograph Only complex reconstructive interventions may achieve an aesthetically and functionally correct implantsupported prosthetic rehabilitation. The aim is to restore the correct three-dimensional relationship between the ridges, increasing bone thickness and decreasing inter-arch distance and augmenting crestal bone height with block grafts associated with sinus lift procedures with lateral approach (45).

Conclusion The treatment of the posterior maxillary edentulism requires an accurate pre-operative diagnosis aimed to achieve a prosthetically-guided, functionally and aesthetically ideal rehabilitation.

The diagnostic steps should be performed according to a precise clinical protocol including: general evaluation of the patient health status and expectations; specific extra- and intra-oral evaluation; three-dimensional evaluation of the inter-arch relationship, with particular attention to the skeletal class and inter-arch dimension; three-dimensional clinical and radiographic analysis of the implant site; evaluation of the cost/benefit ratio of each surgical intervention.

Surgical and prosthetic therapeutic alternatives in the implant-supported rehabilitation of the atrophic lateral-posterior maxilla differ mainly in relation to the anatomical situation and the bone availability (Tab. 1).

The most predictable solution can be chosen when an accurate individual clinical and instrumental evaluation has been performed.

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25. Fugazzotto PA. Immediate implant placement following a modified trephine osteotome approach: success rates of 116 implants to 4-year in function. Int J Oral Maxillofac Implants.

2002;17:113-120.

26. Deporter DA, Caudry S, Kermalli J, Adegbembo A. Further data on the predictability of the indirect sinus elevation procedure used with short, sintered, porous-surfaced dental implants. Int J Periodontics Restorative Dent. 2005;25:585-93.

27. Diserens V, Mericske E, Schäppi P, Mericske-Stern R. Transcrestal sinus floor elevation: report of a case series. Int J Periodontics Restorative Dent. 2006;26:151-9.

28. Ferrigno N, Laureti M, Fanali S. Dental implants placement in conjunction with osteotome sinus floor elevation: a 12-year life-table analysis from a prospective study on 588 ITI implants. Clin Oral Implants Res. 2006;17:194-205.

29. Lum LB. A biomechanical rationale for the use of short implants. J Oral Implantol 1991;17:126-131.

30. Rokni S, Todescan S, Watson P, Pharoah M, Adegbembo AO, Deporter D. An assessment of crown-to-root ratios with short porous-surfaced implants supporting prosthesis in partially edentulous patients. Int J Oral Maxillofac Implants.

2005;20:69-76.

31. Kenealy NJ, Berckmans B, Stach RM. Il fosfato di calcio depositato a livello nanometrico migliora il rapido fissaggio fra impianto e osso in un modello animale. Quintessenza Internazionale 2007; 3bis: 27.

32. Goené R, Bianchesi C, Hürzeler M, Del Lupo R, Testori T, Davarpanah M, Jalbout Z. Performance of short implants in partial restorations: 3-year follow-up of Osseotite implants.

Implant Dent. 2005;14:274-80.

33. Goenè R, Testori T, Trisi P. La nuova superficie implantare NanoTite™ e la neoangiogenesi ossea: studio prospettico randomizzato in doppio cieco controllato con istomorfometria su modello umano. Quintessenza Internazionale 2007; 3bis:34-41.

34. Testori T, Del Fabbro M, Feldman S, Vincenzi G, Sullivan D, Rossi R Jr, Anitua E, Bianchi F, Francetti L, Weinstein RL. A multicenter prospective evaluation of 2-months loaded Osseotite implants placed in the posterior jaws: 3-year followup results. Clin Oral Implants Research 2002;13:154-61.

35. Misch CE, Steigenga J, Barboza E, Misch-Dietsh F, Cianciala

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LJ, Kazor C. Short dental implants in posterior partial edentulism: a multicenter prospective 6-years case series study. J Periodontol. 2006;77:1340-1347.

36. Anitua E, Orive G, Aguirre JJ, Andia I. Five-year clinical evaluation of short dental implants placed in posterior areas: a retrospective study. J Periodontol. 2008;79:42-48.

37. Degidi M, Piattelli A, Iezzi G, Carinci F. Immediately loaded short implants: analysis of a case series of 133 implants.

Quintessence Int. 2007;38:193-201.

38. Fugazzotto PA. Shorter implants in clinical practice: rationale and treatment results. Int J Oral Maxillofac Implants.

2008;23:487-96.

39. Nedir R, Bischof M, Briaux JM, Beyer S, Szmukler-Moncler S, Bernard JP. A 7-year life table analysis from a prospective study on ITI implants with special emphasis on the use of short implants. Results from a private practice. Clin Oral Implants Res. 2004;15:150-7.

40. Arlin ML. Short dental implants as a treatment option: results from an observational study in a single private practice. Int J Oral Maxillofac Implants. 2006;21:769-776 41. das Neves FD, Fones D, Bernardes SR, do Prado CJ, Neto AJ. Short implants - an analysis of longitudinal studies. Int J Oral Maxillofac Implants. 2006;21:86-93. Review.

42. Krekmanov M, Kahn L, Rangert B, Lindstrom H. Tilting of mandibular and maxillary implants for improved prosthesis support. Int J Oral Maxillofac Implants 2000;15:722-730 43. Fortin Y, Sullivan RM, Rangert BR. The Marius implant bridge: surgical and prosthetic rehabilitation for the completely edentulous upper jaw with moderate to severe resorption: a 5-year retrospective clinical study. Clin Implant Dent Relat Res. 2002;4:69-77.

44. Krennmair G, Krianhofner M, Schmid-Schwap M, Piehsliger E. Maxillary sinus lift for single implant supported restorations: a clinical study. Int J Oral Maxillofac Implants.

2007;22:351-358 45. Weingart D, Bublitz R, Petrin G, Kälber J, Ingimarsson S. Kombination der Sinusliftoperation mit der lateralen Kieferkammaugmentation. Ein Behandlungskonzept zur chirurgisch-prothetischen Rehabilitation der extremen Oberkieferalveolarkammatrophie. Mund Kiefer Gesichts Chir 2005;9:317-323.

Case report

Smart-lift technique used in association with a hydroxyapatite-based biomaterial. Clinical outcomes and postoperative morbidity Leonardo Trombelli, DDS, PhD* Giovanni Franceschetti, DDS, PhD * Roberto Farina, DDS, PhD, MSc* Angelo Itro, MD**

*Research Center for the Study of Periodontal Disease, University of Ferrara, Italy **Professor, Department of Pathology of the Head, Neck, and Oral Cavity and Communication, Second University of Naples, Naples, Italy.

Aim:

Recently, we proposed a minimally-invasive technique (Smart Lift) to limit the post-operative morbidity of transcrestal sinus floor elevation procedures. The technique is based on the use of specially-designed drills and osteotomes. The aim of this work is to present data on the clinical outcomes and post-operative morbidity of sinus floor elevation procedures performed using the Smart Lift technique, in association with a hydroxypatite-collagen biomaterial.

Materials: 5 implants were placed in the posterior portions of the maxilla area of 4 patients using the Smart Lift technique in association with hydroxyapatite-collagen biomaterial. Post-operative pain and discomfort were assessed using a 100mm-VAS scale. The incidence of intra- and post-operative complications was recorded. The position of the grafted sinus floor with respect to the implant apex was assessed on periapical radiographs at 6 months post-surgery.

Results: The augmented sites had a pre-surgery residual bone height of 5.4 ± 1.1 mm, while the mean length of the implants inserted in augmented sites was 9.8 ± 0.7 mm. Immediately after surgery, VAS scores for pain and discomfort were 4.0 ± 5.2 and 13.0 ± 16.7, respectively. No complications were observed either during or after the surgical procedure. At 6 months after surgery, a newly formed mineralized tissue entirely covered the portion of the implants exposed into the sinus cavity in all cases.

Conclusions: The Smart Lift technique associated with a hydroxyapatite-collagen biomaterial represents a suitable option to elevate the sinus floor due to a predictable displacement of the sinus floor and a limited post-operative morbidity.

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Key words: maxillary sinus; sinus lift; crestal approach; minimally-invasive surgery

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Introduction Maxillary sinus floor elevation represents a surgical procedure to vertically enhance the available bone, thus permitting the positioning of implants with adequate length in the edentulous posterior maxilla. The transcrestal approach was first presented in 1977 by Tatum (1) and then published in 1986 (2).

The technique consisted of preparing the implant site with a “socket former”, selected according to the implant size to be placed. A “green-stick fracture” of the sinus floor was performed by hand tapping the “socket former” in a vertical direction until a fracture of the sinus floor was obtained. In 1994, Summers (3) modified this technique suggesting the use of a specific set of osteotomes for both preparing the implant site and elevating the sinus floor.

More recently, Fugazzotto (2002) suggested that the pristine bone at sites of implant placement could be drilled up to the sinus floor with a trephine bur, and then used to fracture the sinus floor by hydraulic pressure through osteotomes (4). Since then, many surgical techniques with specially-designed instruments for transcrestal approach were reported in the literature (5-13).

Surgical techniques for sinus floor elevation with transcrestal approach are mainly based on either the fracture or the perforation of the sinus floor by means of osteotomes (5-7) or burs (2, 4, 8-13). However, both osteotome and bur-driven procedures present advantages and limitations. The use of osteotomes may increase the density of the soft maxillary bone while tenting the Schneiderian membrane by the hydraulic pressure of the bone graft pulled into the sinus. Moreover, if implant site preparation is implemented by the use of a trephine drill (4, 8, 13) the trephined core of autogenous bone may usefully contribute to the vertical bone augmentation when used to elevate the sinus

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floor. However, when a thick layer of alveolar bone remains coronal to the sinus floor, osteotome technique may require extensive malleting trauma during sinus floor elevation which may eventually cause post-surgery sequelae, such as Benign Paroxysmal Positional Vertigo (BPPV) (14-16). In addition, the action of osteotomes can be hardly controlled during malleting pressure, thus resulting in an unwanted penetration of the instruments and/or the graft in the sinus cavity with potential membrane perforation. The use of burs with different working length provides controlled perforation of the sinus floor, restraining the action of the cutting edge to the native bone and thus limiting the risk of perforating the sinus membrane.

Unfortunately, the currentlyavailable drilling devices tend not to preserve the residual native bone during implant site preparation and sinus floor perforation, therefore, the burdriven procedure usually calls for the additional use of a graft for sinus augmentation.

Sinus floor elevation procedures are generally achieved by grafting the sinus cavity with autogenous bone, bone substitutes or combination of the two (17-23).

Among bone substitutes, hydroxyapatite (HA) biomaterials represent a family of grafting materials which have come under consideration in the last decades.

HAs are complex calcium phosphates which resemble bone mineral in their chemical composition. HA biomaterials present remarkable biocompatibility with little inflammatory response when implanted within connective and bone tissues (24-26). Moreover, deposition of bone mineral crystals may occur directly onto the surface of implanted HA particles (27, 28). In this context, Biostite® (GABA Vebas, S. Giuliano Milanese, Milan, Italy) is a HA-based biomaterial that has been widely investigated for periodontal and osseous reconstructive surgery. This material is a mixture of synthetic HA (88.0%), equine type I

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collagen (9.5%), and chondroitin sulphate (2.5%).

When implanted in osteoblast or osteoblast-like cell cultures, Biostite® did not affect cell morphology and viability, while promoted cell adhesion and spreading of the primary cells on HA particles to levels similar to those observed for osteoblast–like cell lines (28). Biostite® has been shown to induce in vitro formation of a calcified collagenous matrix when cultured with human osteoblast-like cells (29). This result may be explained, at least in part, by the modulatory effect of Biostite® on the expression of several genes involved in osteoblast proliferation, interaction, and differentiation. Biostite®, in fact, may directly affect osteoblasts by enhancing chondro/osteogenic gene expression and cytoskeleton-related signaling pathways.30 Biostite® was shown highly biocompatible and osteoconductive in animals (31, 32). Several clinical studies widely evaluated the application of Biostite® in either periodontal (33-36) and osseous (37-43) reconstructive procedures.

Recently, we proposed a minimally-invasive procedure, namely the Smart Lift technique, which is characterized by a transcrestal access to the sinus cavity by means of speciallydesigned drills and osteotomes (39-43). The rationale for this technique is to provide predictable vertical bone augmentation into the sinus cavity by using the existing residual bone as a viable graft and limiting the incidence of membrane perforation and postsurgery morbidity.

Previous proof-of-principle studies demonstrated that implants placed concomitantly to a sinus floor elevation procedure performed using the Smart Lift technique may be stable up to 1 year following surgery, along with a limited to null incidence of postoperative intra- and postsurgical complications (39-43).

In a recent prospective case series, 14 implants (mean length 10.3 mm) were placed in the posterior segments of the maxilla

Case report (mean residual bone height as assessed before surgery: 6.1 mm) using the Smart Lift technique in association with different HAbased biomaterials, including Bio-Oss® and Biostite®. At 6 months after surgery, a newly formed mineralized tissue was found at or beyond the level of the implant apex in all cases. 43 On the basis of the available evidence, the Smart Lift technique seems to represent a suitable option to elevate the sinus floor due to a predictable displacement of the sinus floor and a limited post-operative morbidity. To date, however, there is still controversy regarding the most suitable HA-based biomaterial to maintain the space for new bone formation after elevating the sinus membrane.

This is the reason why we decided to evaluate the clinical outcome and the morbidity of the Smart Lift technique used in association with Biostite® HAbased biomaterial in a series of consecutively treated patients.

Material and methods Study population Patients were recruited among those seeking for implantsupported prosthetic rehabilitation of the posterior maxilla. All cases have been selected and treated at the Research Centre for the Study of Periodontal Disease, University of Ferrara, Italy, from May 2007 to January 2009. In all cases the posterior portions of maxillae were edentulous and the residual bone at sites where implants should be placed was judged insufficient according to the prosthetic treatment plan. Before sinus lift procedure, all oral diseases, including periodontal disease, were thoroughly treated. Inclusion criteria to select a patient for the Smart Lift technique were as follows: › indications for implant-supported prosthetic rehabilitation, based on accurate diagnosis and treatment planning; › systemic and local conditions

FIG. 1

According with the patient, we decided to insert: one implant in the first upper premolar area, immediately post-extracion; two implants in second premolar and first upper molar areas, in association with Smart Lift technique The periapical radiograph showed a bone height in #1.5 and #1.6 areas of 7 and 6 mm, respectively.

which are compatible with implant placement and sinus floor elevation procedures; › absence of signs and symptoms of sinus diseases, as confirmed by clinical examination and radiographic assessment immediately prior to maxillary sinus floor augmentation; › residual bone height (i.e. the distance from the bone crest to the sinus floor) of at least 4 mm; › verbal or written informed consent given; › patient willing to comply with the study protocol.

Surgical technique According to the prosthetic treatment planning, the location for implant placement was established, and the residual bone height at such locations was first diagnosed by proper x-ray examination (periapical radiograph, confirmed by CT scan as needed) (Fig. 1). Surgical stents based on diagnostic wax-up have been used only when indicated by the prosthetic treatment plan. All patients were administered an antibiotic premedication (amoxicillin, 2 g 1 hour prior to the surgical procedure). After full-thickness flap elevation, a first drill (Locator Drill) was used to perforate the cortical bone to a depth of ≤3.0

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mm at the site where the implant had to be placed. A second drill (Probe Drill), with a diameter of 1.2 mm and cutting only at the top edge, was utilized to define the position and orientation of the implant. In order to minimize the risk of sinus floor perforation, this bur was used with an adjustable stop device which was always set at least 1 mm shorter than the rWL. Then, the “Probe Osteotome” (Ø 1.2 mm) was carefully inserted into the site prepared by the Probe Drill, and gently forced in an apical direction through the cancellous bone until the cortical bone resistance of the sinus floor was met. Therefore, the Probe Osteotome provided the “surgical working length” (sWL), which represented the true anatomical distance from the bone crest to the sinus floor in the exact location where the implant had to be placed (Fig. 2). Thus, the working action of all manual and rotating instruments that were used in subsequent surgical steps were set at the sWL by using the proper adjustable stop device.

When needed, a Radiographic Pin (Ø 1.2 mm) was used to check the orientation and depth of the prepared site by means of a periapical x-ray. The Radiographic Pin handle has a diameter of 4.0

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FIG. 3

The Smart Lift Drill created a bone core up to the sinus floor in both the surgical sites.

FIG. 2

After placing one post-extraction implant in the first premolar area, we utilized Probe Drill (Ø 1.2) and subsequently Probe Osteotome(Ø 1.2), confirming a surgical working length (i.e. the anatomical distance between the bone crest and the cortical floor) of 7 mm and 5 mm in the second premolar (Fig. II, a) and first molar (Fig. II, b) areas, respectively. All the stop devices were set at the surgical working length.

mm, thus permitting to evaluate the spatial relationship between the prepared site and the bucco-lingual as well as mesio-distal dimensions of the alveolar ridge. This helped to determine the diameter of the implant to be placed. Then, a “Guide Drill” of Ø 3.2 mm (for implant Ø: 3.75 ÷ 4.5 mm) or Ø 4.0 mm (for implant Ø: 4.8 ÷ 5.0 mm) was used.

This drill followed the Ø 1.2 mm site preparation and created a crestal countersink, 2 mm deep, where the trephine bur (Smart Lift Drill) was then inserted. Such countersink enabled the trephine bur to centre its working action according to the desired orientation. The “Smart Lift Drill” (Ø 3.2 or 4.0), set at the sWL, produced a bone core up to the sinus floor (Fig. 3). Following the removal of the trephine bur, the bone core was then condensed and malleted to fracture the sinus floor by means of a calibrated osteotome (Smart Lift Elevator, Ø 3.2 or Ø 4.0) that corresponded to the diameter of the

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FIG. 4

Smart Lift Elevator, with the stop set at the surgical working length, condensed the bone core into the sinus.

FIG. 5

Biostite® was grafted in both the surgical sites.

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Case report

FIG. 7

Immediately post-operative periapical radiograph showed newly formed mineralized tissue entirely covering the apical portion of the implants (SPI Element, Thommen Medical, CH).

FIG. 6

Smart Lift Elevator, with the stop set at the surgical working length, condensed Biostite® into the sinus.

trephine preparation (Fig. 4). If the alveolar bone core was found to be inside the trephine, the bone core was gently removed from the trephine and replaced in the alveolar bone preparation. The osteotome was used under gently malleting forces to implode the trephined bone core over the sinus floor. In relation to the extent of vertical bone augmentation to be achieved, a bone graft, such as Biostite®, was further grafted (Fig. 5) and condensed into the sinus by the osteotome. The graft was condensed with the Smart Lift Elevator used at the sWL, thus preventing any unwanted penetration of the instruments into the sinus cavity (Fig. 6). In all cases, implants were positioned with healing abutment at the same surgical session. Flaps were closed by means of 6-0 Vicryl® (Johnson & Johnson, Neuchatel, Switzerland) sutures. Patients were prescribed NSAID therapy (nimesulide 100 mg tablets) as needed, and chlorhexidine

FIG. 8

At 6 months after surgery, the periapical radiograph showed, once again, newly formed mineralized tissue entirely covering the portion of the implants exposed into the sinus cavity.

mouthrinse, 10 ml t.i.d. for 3 weeks. Sutures were removed 7 days after surgery. Post-operative X-ray were performed immediately postoperatively and 6 months after surgery (Fig. 7, 8). All patients received a prosthetic rehabilitation within 4 to 6 months after surgery (Fig. 9).

Clinical recordings At the time of sinus lift procedure, the following data were recorded: › “radiographic working length” (rWL): the distance from the bone crest to the sinus floor as assessed on periapical radiographs; › surgical working length” (sWL): as assessed by the Probe Osteotome; › duration of the Smart Lift proce-

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dure (in minutes, from cortical perforation to implant placement); › incidence of membrane perforation, as evaluated by the Valsalva maneuver, or other intra-surgery complications; › primary stability of the implant (evaluated at 30 N torque).

Immediately following surgery, patients were asked to assess: › pain experienced during the sinus lift procedure, recorded by a 100-mmVAS (ranging from “no pain” to “intolerable pain”); › discomfort/trauma experienced during the sinus lift procedure, recorded by a 100-mmVAS (ranging from “no discomfort” to “maximum discomfort”);

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FIG. 9

Prosthetic rehabilitation at 6 months after surgery.

FIG. 10

› presence of complications related to the sinus lift procedure.

At 7 days post surgery, the following recordings were performed: › dosage of (nimesulide 100 mg tablets) assumed during the postsurgery period; › presence of post surgery complications related to the sinus lift procedure.

Radiographic and morphometric evaluations Radiographic evaluations were based on periapical radiographs.

Assessment of rWL at the sites of implant placement was made on x-ray taken immediately before the sinus augmentation procedure. A first post-surgery radiograph (baseline) was taken within 2 weeks from the Smart Lift procedure to evaluate the implant positioning and the amount of sinus grafting around the apical portion of the implant (Fig. 7). Subsequently, periapical radiographs were taken at 6 months after surgery (Fig. 8).

Outcome variables were recorded on the radiographs using a digital ruler. To evaluate the change in height of grafted sinus floor for each implant, the variables were: (i) implant length (IL), defined as the distance from the apex to the head of the implant; and (ii) bone level (BL), defined as the distance from the top of the radio-opaque grafted area to the head of the implant. Both measurements were taken at the middle longitudinal axis of the implant.

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VAS score to assess the immediately post-operative pain and discomfort as perceived by the patient.

To express the relationship between sinus-graft height and the implant length, BL ratio was calculated as BL/IL. A value of 1.0 or higher indicates that the grafted sinus floor covers the ‘implant apex’. A value of less than 1.0 indicates that the implant apex is not completely covered by the grafted sinus floor.

Therefore, the relationship between grafted sinus floor and implant was classified into three groups: Group I, in which the grafted sinus floor was above the implant apex; Group II, in which the implant apex was level with the grafted sinus floor; and Group III, in which the grafted sinus floor was below the implant apex (44). All measurements were undertaken by a single investigator (GF) who was not involved in the surgical procedure.

Radiographs of the same patient were blinded as to the observation interval.

Statistical analysis The patient was regarded as the statistical unit. Data are expressed as means ± standard deviation.

Results Four consecutively-treated patients (2 men, 2 women; mean age, 54.7 years) were included in

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the study. rWL and bone width amounted to 5.4 ±1.1 mm and 5.6 ± 1.3 mm, respectively. The mean duration of the sinus lift procedure was 19.0 ± 6.4 min.

No membrane perforation or any other surgical complications were recorded during or immediately after the procedure. A total of 5 implants were placed, with 1 patient contributing 2 implants.

The mean length of the implants inserted was 9.8 ± 0.7 mm (range 9.0 – 11.0 mm). Immediately after implant placement, all implants showed primary stability.

Transmucosal and submerged healing was used in 2 implants, cover screw in 3. In all cases, the trephined bone core created by the Smart Lift Drill and an additional graft of Biostite® was used for sinus floor elevation.

Immediately after surgery, VAS scores for pain and discomfort were 4.0 ± 5.2 (range 0-11) mm and 13.0 ± 16.7 (range 0-35) mm, respectively (Fig. 10). At 7 days postsurgery, only one patient stated that he had assumed nimesulide 100 mg tablets, with a total dosage of 5 tablets during the first 7 postoperative days. No implants were lost during the 6month observational follow-up. In all cases an implant-supported prosthesis was inserted at 4 to 6 months following implant placement. Mean BL ratio varied from 1.2 ± 0.1 (range: 1.2 – 1.3)

Case report at baseline to 1.2 ± 0.1 (range: 1.0 – 1.3) at 6 months following surgery.

Discussion and conclusion The present case series illustrates a minimally-invasive procedure aimed at sinus floor elevation with transcrestal approach for implant insertion, used in association with a hydroxyapatite-based biomaterial. The augmented sites showed a mean residual bone height, as assessed during surgery, of 5.4 mm, while the mean length of the implants inserted in augmented sites was 9.8 mm. At 6 months after surgery, periapical radiographs showed that a newly formed mineralized tissue entirely covered the portion of the implants exposed into the sinus cavity and extended above the implant apex in 4 out of 5 implants. No complications were observed either during the surgical procedure (e.g. membrane perforation) or following surgery (e.g. BPPV). The rationale for this technique was essentially derived from a previously described procedure where the combined use of a trephine bur and osteotomes was suggested (4).

Previous reports with such technique showed a cumulative success rate of 98.0% following 13-48 months of follow-up (4).

Although proven effective, this technique seems highly technique-sensitive, particularly with respect to the control of the working action of both trephine bur and osteotome. It may be conceivable that, during the drilling action of the trephine bur and the mallet pressure onto the osteotomes, a direct damage of the sinus membrane due to instrument penetration over the sinus floor can occur.

In our procedure, all instruments in the surgical set are characterized by laser marks at 4-5-6-7-8-9-10-11 mm to allow for an accurate control of the working length.

Moreover, the working action of the rotating and manual

instruments is restricted to the residual (native) bone. The working length is first established radiographically, but then confirmed by the combined use of the Probe Drill and Probe Osteotome. Probe Drill is provided with a top cutting edge which can easily proceed into the cancellous bone reaching the proximity of the sinus floor. Then, the surgical working length is defined by tactile perception of the cortical bone of the sinus floor derived from the gentle use of the Probe Osteotome. Once the surgical working length is established, the use of adjustable stop devices would dictate the extent of the working action of manual and rotating instruments, thus minimizing the risk for membrane perforation and post-surgery infections. Other techniques have been reported where the use of burs of variable length and provided with a shoulder stop have been used to perforate the sinus floor (8). Unfortunately, in such procedure the selection of the working length of the rotating instruments is only based on the radiographic examination, leading to potential under- or overestimation of the amount of residual bone height.

Vertical augmentation of the implant site is provided by the condensed trephined bone core which is displaced into the sinus. This intrusion osteotomy procedure elevates the sinus membrane, thus creating a space for blood clot formation. It is conceivable that the contribution of the bone core to intra-sinus bone formation may relate to the amount of residual bone at the implant site, i.e. the more native bone pushed into the sinus, the more newly formed bone. When a limited amount of residual bone is present with respect to the amount of bone needed for proper implant placement, bone formation may be implemented by the additional use of a graft. In our study, a graft of hydroxyapatite-based material was used in conjunction with the trephined bone core to elevate the sinus floor. Grafting material was added incrementally and condensed into the sinus by the

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osteotome. During the grafting procedure, it is the graft biomaterial only that exerts the hydraulic pressure to “tent” the sinus membrane, while any direct penetration of the osteotome into the sinus cavity is prevented by the adjustable stop device.

Previous studies seem to suggest an enhanced osteoinductive/ conductive potential with the additional use of bone substitutes.

Pjetursson et al. (22) compared the transcrestal sinus floor elevation by means of osteotomes with and without the additional use of deproteinized bovine bone matrix. A gain in radiographic bone height of 4.1 mm and 1.7 mm where observed in grafted and non-grafted sites, respectively. In our study, no membrane perforation was recorded during or immediately after the sinus lift procedure. Recently, a systematic review (23) reported an incidence of membrane perforation ranging from 0% to 21.4%, and postoperative infection from 0% to 2.5% following transcrestal sinus elevation by means of different surgical procedures. In an experimental evaluation of maxillary sinus membrane response following elevation with osteotome technique in human cadavers, membrane perforation was observed in 6 out of 25 implants (24%), the risk being increased with an increasing extent of sinus floor elevation to be obtained (45). A preclinical study demonstrated that implants intentionally exposed for 4-8 mm into the sinus cavity following transcrestal sinus elevation procedures were only partially recovered by sinus mucosa, the exposed part of the implant being recovered by debris potentially resulting in sinus infection (46).

Extensive malleting trauma during sinus floor elevation with osteotomes may cause BPPV, a benign syndrome characterized by short, recurrent episodes of vertigo, initiated by movements of head lateralization and extension toward the affected site (14-16).

BPPV is usually “self-limiting”, however, symptoms may subside or disappear after 6 months and require professional intervention (47).

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In our study, no episodes of BPPV were observed at either the time of sinus lift procedure or 7 days after surgery. In this respect, the combined utilization of a trephine bur in close proximity to the sinus floor limits the need for repeated malleting. Therefore, the Smart Lift technique may result less traumatic and disconcerting to the patient with respect to the conventional osteotome procedures.

The presence of newly mineralized tissue covering the portion of the implants exposed into the sinus cavity and extending above the implant apex in 80% of cases, suggests that Biostite® could be efficiently used as a biomaterial for the osseous reconstruction, even in transcrestal sinus floor elevation procedures. These findings are in agreement with our previous studies, where the biomaterial was used for periodontal or alveolar bone reconstruction (35, 41, 43).

In conclusion, the Smart Lift technique associated with Biostite® represents a minimally-invasive surgical option for sinus floor elevation. The technique is based on a standardized, user-friendly sequence of manual and rotating instruments used with a controlled working action aimed at preventing surgical complications. However, further controlled clinical trials are needed to evaluate the effectiveness and safety of this technique compared to other sinus floor elevation procedures.

Acknowledegments We wish to thanks Dental Trey (Fiumana, FC, Italy), for kindly providing the Smart Lift surgical set and GABA Vebas s.r.l. (Roma, Italy) for kindly providing the graft biomaterial.

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14. Galli M, Petracca T, Minozzi F, Gallottini L. Complications in implant surgery by Summers’ technique: benign paroxysmal positional vertigo (BPPV).

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15. Rodríguez-Gutiérrez C, RodríguezGómez E. Positional vertigo afterwards maxillary dental implant surgery with bone regeneration. Med Oral Patol Oral Cir Bucal 2007;12:E151-153.

16. Peñarrocha-Diago M, Rambla-Ferrer J, Perez V, Pérez-Garrigues H. Benign paroxysmal vertigo secondary to

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17. Tong, D.C., Rioux, K., Drangsholt, M. & Beirne, O.R. A review of survival rates for implants placed in grafted maxillary sinuses using meta-analysis.

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18. Wallace, S.S. & Froum, S.J. Effect of maxillary sinus augmentation on the survival of endosseous dental implants. A systematic review. Annals of Periodontology 2003;8:328-343.

19. Emmerich, D, Att, W & Stappert, C. Sinus floor elevation using osteotomes: a systematic review and meta-analysis.

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20. Pjetursson, B.E., Tan, W.C., Zwahlen, M. & Lang, N.P. A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation.

Part I: Lateral approach. Journal of Clinical Periodontology 2008;35 (Suppl. 8):216-240.

21. Pjetursson, B.E., Rast, C., Brägger, U., Schmidlin, K., Zwahlen, M. & Lang, N.P. Maxillary sinus floor elevation using the (transalveolar) osteotome technique with or without grafting material. Part I: implant survival and patients’ perception. Clinical Oral Implants Research 2009;20:667676.

22. Pjetursson, B.E., Ignjatovic, D., Matuliene, G., Brägger, U., Schmidlin, K. & Lang, N.P. Transalveolar maxillary sinus floor elevation using osteotomes with or without grafting material. Part II: radiographic tissue remodeling.

Clinical Oral Implants Research 2009;20:677-683.

23. Tan, W.C., Lang, N.P., Zwahlen, M. & Pjetursson, B.E. A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation.

Part II: Transalveolar technique.

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24. Beckham, C. H., Greenlee, J. & Crebo, A. R. Bone formation at a ceramic implant surface. Calcified Tissue Research 1971;8:165–171.

25. Jarcho, M., Kay, J. F., Gumaer, K. I., Doremus, R. H. & Drobeck, H. P. Tissue cellular and subcellular events at a boneceramics interface. Journal of Bioengineering 1977;1:79–92.

26. De Putter, C., De Groot, K. & SillevisSmith, P.A.E. Transmucosal implants of dense hydroxyapatite. Journal of Prosthetic Dentistry 1983;49:87-95.

27. Ogiso, M. Bone formation on HA implants: a commentary. Journal of Long Term Effects of Medical Implants

Case report 1998;8:193-200.

28. Trombelli, L., Penolazzi, L., Torreggiani, E., Farina, R., Lambertini, E., Vecchiatini, R. & Piva, R. Effect of hydroxyapatite-based biomaterials on human osteoblast phenotype. Minerva Stomatologica 2010;59:103-115.

29. Serre, C. M., Papillard, M., Chavassieux, P. & Boivin, G. In vitro induction of a calcifying matrix by biomaterials constituted of collagen and/or hydroxyapatite: an ultrastructural comparison of three types of biomaterials. Biomaterials 1993;14:97-106.

30. Sibilla, P., Sereni, A., Aguiari, G., Banzi, M., Manzati, E., Mischiati, C., Trombelli, L. & del Senno, L. Effects of a hydroxyapatite-based biomaterial on gene expression in osteoblast-like cells. Journal of Dental Research 2006;85:354-358.

31. Frank, R.M., Duffort, J.F., Benqué, E.P. & Lacout, J.L. [Histological comparison of the effect of different implanted hydroxyapatites in the animal periodontium]. Journal de Parodontologie 1991;10:255-264.

[Article in French] 32. Brunel, G., Benqué, E. P., Barthet, P., Marin, P., Melix, C. & Spilthooren, H. Etude histologique de l’implantation de Bioapatites dans les de´fauts parodontaux chez le chien Beagle.

Journal de Parodontologie 1992;11:419–426.

33. Benqué, E. P., Zahedi, S., Brocard, D., Oscaby, F., Justumus, P. & Brunel, G. Combined collagen membrane and hydroxyapatite/collagen chondroitinsulfate spacer placement in the treatment of 2-wall intrabony defects in chronic adult and rapidly progressive periodontitis patients.

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34. Scabbia, A. & Trombelli, L. A comparative study on the use of a HA/collagen/chondroitin sulphate biomaterial (Biostite) and a bovinederived HA xenograft (Bio-Oss) in the treatment of deep intra-osseous defects.

Journal of Clinical Periodontology 2004;31:348-355.

35. Trombelli, L., Farina, R., Franceschetti, G. & Calura, G. Single Flap Approach with Buccal Access in Periodontal Reconstructive Procedures. A Case Series. Journal of Periodontology 2009;80:353-360.

36. Trombelli, L., Simonelli, A., Pramstraller, M., Wikesjö, U.M.E. & Farina, R. Single Flap Approach with and without Guided Tissue Regeneration and a Hydroxyapatite Biomaterial in the Management of Intraosseous Periodontal Defects.

Journal of Periodontology 2010 (in press).

37. Benqué, E., Zahedi, S., Brocard, D., Marin, P., Brunel, G. & Elharar, F.

Tomodensitometric and histologic evaluation of the combined use of a collagen membrane and a hydroxyapatite spacer for guided bone regeneration: a clinical report.

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47. Honrubia V, Baloh RW, Harris MR, Jacobson KM. Paroxysmal positional vertigo syndrome. Am J Otol.

1999;20:465-470.

38. Rebaudi, A., Silvestrini, P. & Trisi, P. Use of a resorbable hydroxyapatitecollagen chondroitin sulfate material on immediate postextraction sites: a clinical and histologic study.

International Journal of Periodontics and Restorative Dentistry 2003;23:371-379.

39. Trombelli, L., Minenna, P., Franceschetti, G., Farina, R. & Minenna, L. SMART-LIFT: una nuova procedura minimamente invasiva per la elevazione del pavimento del seno mascellare.

Dental Cadmos 2008;76:71-83.

40. Trombelli, L., Minenna, P., Franceschetti, G., Farina, R. & Minenna, L. Tecnica Smart-Lift per il rialzo del seno mascellare con approccio crestale. Implantologia 2008;6:9-18.

41. Trombelli, L., Minenna, P., Franceschetti, G., Farina, R. & Minenna, L. SMART-LIFT: una procedura minimamente invasiva per il rialzo del pavimento del seno mascellare con accesso transcrestale.

Efficacia clinica e morbidità postoperatoria.

Dental Clinics 2010;2:25-34.

42. Trombelli, L., Minenna, P., Franceschetti, G., Minenna, L., Itro, A. & Farina, R. A Minimally Invasive Approach for Transcrestal Sinus Floor Elevation: a Case Report.

Quintessence International 2010;41:363-369.

43. Trombelli, L., Minenna, P., Franceschetti, G., Minenna, L. & Farina, R. Transcrestal Sinus Floor Elevation with a Minimally Invasive Technique. A Case Series. Journal of Periodontology 2010;81:158-166.

44. Hatano M, Shimizu Y, Ooya K. A clinical long-term radiographic evaluation of graft height changes after maxillary sinus floor augmentation with a 2:1 autogenous bone/xenograft mixture and simultaneous placement of dental implants. Clin Oral Implants Res 2004;15:339-345.

45. Reiser GM, Rabinovitz Z, Bruno J, Damoulis PD, Griffin TJ. Evaluation of maxillary sinus membrane response following elevation with the crestal osteotome technique in human cadavers. Int J Oral Maxillofac Implants 2001;16:833-840.

46. Jung JH, Choi BH, Zhu SJ, et al. The effects of exposing dental implants to the maxillary sinus cavity on sinus complications. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.

2006;102:602-605.

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Case report

Endodontic surgery: a critical review Silvio Taschieri Monica Bortolin Tommaso Weinstein Igor Tsesis* Massimo Del Fabbro

IRCCS Istituto Ortopedico Galeazzi, Department of Health Technologies, UniversitĂ degli Studi di Milano, Milano, Italy *Department of Endodontology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel

Aim:

The main objective of periapical surgery is to obtain periradicular tissue regeneration, including the formation of a new attachment apparatus by exclusion of any noxious agent within the physical confines of the affected root. Consequently one of the target of root-end preparation techniques during endodontic surgery is to create a well cleaned and shaped cavity to be filled, in order to seal the apical terminus of the root canal system.

Methods: A review of the literature was performed by using electronic and handsearching methods for the endodontic bone lesion, root-end management and periradicular surgery healing criteria.

Results: There are many published reports regarding endodontic surgery. Our search showed that the main benefit considered in evaluating the outcome of surgical treatment is the probability of healing. Adherence to a strict endodontic surgical protocol, a minimally invasive surgical technique, a careful root-end preparation using contemporary techniques, visual magnification, proper materials and a correct case selection might be key factors to the success of treatment.

Conclusions: long-term outcome of the surgical and non-surgical approach for the retreatment of periapical lesions is very similar. Even if a faster healing rate was observed for surgical cases, there are no scientific data that support the concept of a systematic difference in healing potential between surgical and non-surgical re-treatment.

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Key words: endodontic surgery, root-end management, perapical bone lesion, operating microscope

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Taschieri S. et al.

Introduction The aim of endodontic treatment is to clean and disinfect the root canal system in order to reduce the number of micro-organisms, remove necrotic tissue and finally seal the system to prevent contamination. The persistence of micro-organisms within the root canal system may induce an inflammatory response within the periapical tissues resulting in local bone destruction. It has been hypothesized that the extraradicular infection is not always dependent on the root canal infection (1-3). Other conditions, such as cysts and the presence of foreign materials within the periapical tissues, may in fact sustain periapical disease (3).

Periapical disease must be carefully evaluated so that a decision can be made among nonsurgical retreatment, surgical retreatment or tooth extraction (1,4).

When the disease is diagnosed, extraction is frequently performed (5). This trend is disappointing in view of the possibility of conservatively treating posttreatment disease by either orthograde retreatment or apical surgery (6). This may be reflective of clinicians’ hesitation regarding which treatment modality to prescribe. Surveys among general practitioners and endodontists have shown considerable variability in selecting between orthograde retreatment and apical surgery, suggesting that this choice is subjective and inconsistent (1,4-9).

The purpose of this study is to present a comprehensive critical review regarding endodontic surgery.

Materials and methods Criteria for considering studies for this review › Types of studies: all clinical studies comparing endodontic therapy performed with or without using one or more types of magnification device; clinical studies comparing two or more

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›

›

›

›

root-end filling material; clinical studies comparing different endodontic surgical procedures and different evaluations of success and failure; all reviews regarding endodontic surgery.

The following electronic databases were searched: Cochrane Oral Health Group Specialised Register, Cochrane Central Register of Controlled Trials (Central), Medline (1966 to present), EMBASE (1974 to present). The last electronic search was performed on November 27th, 2008.

Handsearching: all issues of the following journals (Evid Based Dent, J Endod, Int Endod J, Endod Dent Traumatol, Oral Surg Oral Med Oral Pathol Oral Radiol Endodontol, Quintessence Int, J Oral Maxillofac Surg, Int J Oral Maxillofac Surg, Br J Oral Maxillofac Surg, Int J Periodont Restorative Dent, Schweiz Monatsschr Zahnmed) were handsearched as being of particular importance to this review.

Language: no language restriction was placed. In case of need for translations, these were provided by appropriate Departments of University of Milan. The authors of identified articles written in languages other than English were contacted for clarification.

Data collection: a quality assessment of the included studies was independently carried out in duplicate. The data were extracted independently and in duplicate (ST, MB).

The titles and abstracts (when available) of all reports identified through the searches were scanned independently by two authors (ST, MB). Disagreements were resolved by discussion. All studies meeting the inclusion criteria underwent validity assessment and data extraction.

Literature analysis and considerations The main objective of periapical surgery is to obtain periradicular

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tissue regeneration, including the formation of a new attachment apparatus by exclusion of any noxious agent within the physical confines of the affected root.

Periapical bone lesion and endodontic surgery A number of clinical studies have been published on periradicular surgery using microsurgical endodontic procedure (10-22).

The overall success rate showed in abovementioned studies is generally high. Nevertheless, many variables can affect the prognosis of the surgical treatment, such as surgical procedure, material, radiographic and clinical outcome assessment, patient’s systemic condition, type of tooth, quality of previous root canal treatment or retreatment and of coronal restoration. Furthermore, different criteria for the evaluation of success and failure of the treatment have been adopted.

When there is heterogeneity for clinical variables and success criteria, a direct comparison amongst or between different studies is very difficult (20). The successful outcome of endodontic surgery can be affected by a myriad of factors. It is difficult, however, to estimate the weight of all the parameters potentially affecting the outcome (20). A multivariate analysis on the influence of two postoperative complications and 18 different clinical factors upon surgical success has provided some trends and correlations, but even these findings cannot be generalized (23).

In 1991, Gutmann and Harrison divided clinical factors that may influence the prognosis of endodontic surgery in certain and questionable causes (24). The latter included factors for which few or conflicting data exist to support their role in the healing process. Among the questionable tooth-related factors there was the amount and location of bone loss (24-26). Two retrospective studies indicated that the prognosis is substantially reduced in teeth with a total loss of buccal bone plate (26, 27).

With the introduction of guided tissue regeneration (GTR) in oral

Case report FIG. 1

Fig 1: 1a & 1b Periapical bone defect without marginal lesion: 1a cortex not eroded (Ia); Lingual palatal cortex eroded; 1b with a buccal surgical approach, this will result in a transosseous or through and through bone defect; 1c Periapical lesion with or without lingual erosion and concomitant marginal lesion: no communication between the separate lesions (IIa); the two lesions are fused = communicating apicomarginal or endodontic-periodontal lesion (IIb); 1d Lateral or furcational lesion (with or without marginal lesion): no communication to alveolar crest/marginal periodontium (IIIa), communication to alveolar crest/marginal periodontium (IIIb).

Lesions in class III include juxctaradicular lateral or furcational lesions originating from accessory canals or after iatrogenic perforation.

and periodontal surgery, a new treatment option became available for such defects. The

placement of a mechanical barrier, such as a membrane, over an osseous defect, can prevent

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the faster proliferating oral epithelium and gingival connective tissue from growing into the defect. The slower proliferating cells with osteogenic potential can then repopulate the defect, resulting in a more predictable bone repair (28).

In 2001, Von Arx and Cochran proposed a classification of membrane application in endodontic surgery, based on typical periradicular lesions which are distinguished by their location, extension or pathway of infection (29) (Fig. 1).

Lesions in class I comprised bony defects located at the apex. The defect may erode the buccal and/or lingual cortex. Lesions in class Ia showed compromised bony defects located at the apex without marginal lesion and Ib lesions included through-andthrough bone defects. In this class, the main objective of membrane application is the regeneration of periapical tissues, including the reestablishment of an apical attachment apparatus.

Few clinical studies evaluated the efficacy of GTR in these type of lesions (30-34). Lesions in class

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Taschieri S. et al.

FIG. 2

2a-b buccal bone defect after rootend resection; 2c appearance of the smoothed root-end surface under advanced magnification; 2de-f use of the retrotip allowed creation of the root canal cavity; 2g a paper cone was used to dry the root-end cavity; 2h successful cementation of the cavity located at the root-end.

II comprised apical lesions with concomitant marginal lesion.

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These lesions are commonly called combined endodontic-

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periodontal lesions. Lesion IIa showed separate lesion; lesion

Case report

FIG. 3

3a Radiograph obtained during a preliminary visit showing a periapical lesion of 2.5.

3b Radiograph obtained at 1 year followup showing complete healing.

class IIb showed the two lesions fused (communicating apicomarginal or endodonticperiodontal lesion). In this class, GTR is employed to regenerate periapical and marginal tissues at the same time. Lesions in class III included juxtaradicular lateral or furcational lesions originating from accessory canals or after iatrogenic perforation. Lesions class IIIa showed no communication to alveolar crest/marginal periodontium and lesions class IIIb showed communication to alveolar crest/marginal periodontium. In this class, the membrane technique is used for periradicular tissue regeneration with or without marginal tissue regeneration.

After analysing the literature concerning the abovementioned classification, we can observe that delays or alterations in healing have been reported when lesion size was greater than 5 mm (23, 35, 36). Several authors showed that the prognosis for smaller lesions after periradicular surgery is better in respect to larger ones (26, 27, 37, 38).

Hirsch et al. (26) found a success rate of only 27% among 33 teeth with total buccal bone loss, compared to a healing rate of

50% in patients with intact buccal bone. Skoglund and Persson identified an initial success rate of 37% with total buccal bone loss, with 33% listed as uncertain and 30% as unsuccessful. Over a four year evaluation, the success rate was increased to only 38.5% (27).

Rubinstein et al. (16) observed that both lesions of small size (0 to 5 mm) and those of medium size (6 to 10 mm) healed within 7.25 months, while lesions greater than 10 mm healed within 11 months.

Some authors suggested that the size of the preoperative lesion has no bearing on the ultimate resolution of the periradicular defect (39-40). However, in 1972, Rud et al. (25) observed that tooth location and the extent of cortical bone loss may have a significant influence on healing pattern.

Several studies in humans and animals have evaluated the concept of GTR. This has led to the development of membranes or barriers that allow the cellular regrowth of periodontal defects caused by disease or surgical trauma (40). The use of a barrier in such lesions is an attempt to improve the self-regenerative healing process, by excluding

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undesired proliferation of gingival connective tissue or the migration of the oral epithelium into such defects, that can impair the formation of normal trabecular bone (41).

In GTR many authors underlined the importance of maintaining the proper space below the membrane (42-44).

In order to achieve a more predictable regeneration, some authors suggest the combined use of barrier membranes and graft materials that may act as space maintainers (45-48).

In 1995, Pecora et al. showed that large periapical lesions healed more rapidly and with better quality bone when a membrane (e-PTFE-Goretex) was used (30). In 2001, Pecora et al. designed a clinical randomized study to evaluate the adjunctive effect of calcium sulphate grafts on the surgical treatment of through-and-through periradicular lesions (32). The results of this study demonstrated that the addition of calcium sulphate as a bone graft during the conventional surgical treatment improved the clinical outcome. Tob贸n et al.

(33) concluded that the use of non absorbable membranes or a combined use of non absorbable membranes and resorbable hydroxyapatite improved the predictability of clinical, radiographic and histological healing over conventional technique. This study provided histological results comparable to experimental studies in animals (49, 50). Conversely, Garrett et al.

(34) in a prospective controlled study suggested that placement of a membrane over the bony opening created during a periradicular surgical procedure has no beneficial effect on the rate of healing, and the added expense to the patient would not be warranted.

In 1998, Santamaria et al. also showed no statistical significance in density and residual volume using or not a resorbable or a non-resorbable membrane (31). Some histomorphometric and histological studies in the animal model found no significant difference in bone regeneration using or not GTR (51a-51b). Similar to the latter

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Taschieri S. et al. studies, Taschieri et al. (52) did not find significant difference in outcome between GTR and control group in the treatment of periapical lesions larger than 10 mm. In 2001, Von Arx suggested that clinicians might hesitate to apply the GTR principle in endodontic surgery because of good long-term results obtained with surgical approaches that do not include membrane application (29). In addition, higher cost, a more complex operative technique, possibly new healing complication, and lack of research with regard to predictability and long term outcome may have discouraged surgeons from employing this surgical technique for the treatment of class I periapical lesions (29). The same author declared that in the near future, the most attractive indication for GTR with membranes and/or grafts in endodontic surgery is the treatment of combined endodontic-periodontal lesions (class II). In fact a lot of case reports and some clinical study underlined that the application of GTR techniques and periradicular surgery in teeth with apicomarginal defects may improve the rate of healing. It cannot be excluded that this variable may affect the prognosis and the outcome of the surgical treatment using or not GTR. Root-end management Management of the resected rootend during periradicular surgery is critical to a successful outcome.

Root-end cavity preparation One of the aims of root-end preparation techniques during endodontic surgery is to create a well cleaned and shaped cavity to be filled, in order to seal the apical terminus of the root canal system (53). Root-end cavities have traditionally been prepared by means of small round or inverted cone burs in a microhandpiece. The introduction of ultrasonic retrotips has brought advantages in the procedure of preparation and cleaning of the root-end cavity (54).

A number of clinical studies have been published on periradicular

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surgery using microsurgical retrotips (10,12,15-17,20-22).

All these studies reported high success rates for periradicular healing (ranging from 82% to 96.8%). Nevertheless, different criteria for the evaluation of success and failure of the treatment have been used. When there is heterogeneity for clinical variables and success criteria, a direct comparison between different studies is very difficult.

Retrotips enable the long axis of the tooth to be followed, while preserving the morphology of the canal (55). Apical cavities may be shaped easily, safely and with greater precision as compared to using conventional handpieces (13,53,56,57). A well shaped root-end cavity, which is more centrally placed and smaller than that produced by microhandpieces and burs, may also reduce the risk of root perforation in deeply fluted roots (14). In addition, the utilization of ultrasonic retrotips requires small bone cavity (54), and the cutting bevel obtained on the resected root-end can be quite perpendicular to canal long axis.

This fact might be beneficial because it decreases the number of exposed dentinal tubules at the resected root surface, minimizing apical leakage (58-60). Retrotips shows differences in material, design and angulation of the terminal portion.

The tip angulation choice is determined by the position of the root canal, in order to match the long axis of the root-canal system as much as possible.

Root-end filling There has long been a debate on whether a root-end filling should always be placed and whether a better “apical seal” can be achieved by its placement, especially when the root canal is already well filled. Friedman (61) argued that a root-end filling should be placed routinely. A tooth lacking a root canal filling will need it, and even if the root canal looks apparently well filled, it may still contain infection. In case of extra-radicular infection, the possible co-existence of intraradicular infection cannot be

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excluded, so again a root-end filling is essential.

An ideal filling material should seal the pathways of communication between the root canal system and its surrounding tissues. It should also be nontoxic, noncarcinogenic, nongenotoxic, biocompatible, insoluble in tissue fluids and dimensionally stable.

Many clinical studies have reported poor outcomes with amalgam root-end fillings when the results were carefully reviewed and strict healing criteria applied (62-65).

Actually there is no shortage of opponents. Amalgam can no longer be considered the root-end filling material of choice and can be confined to history. › Zinc oxide-eugenol (ZOE) cements The biological properties of ZOE cements differ according to formulation and age of the material. Free eugenol remains trapped in the set mass of zinc eugenolate and is released by progressive hydrolysis of the cement surface (66). Variation in the composition of the reinforced ZOE cement may affect the effect of cement dissolution and eugenol release, producing the observed differences in cytotoxicity (67).

Actually, over a period of time, the cytotoxicity of ethoxybenzoic acid (EBA) gradually reduces to nil, the explanation being that EBA gradually contains less eugenol. Efforts were made to further improve the biocompatibility of reinforced ZOE cements by adding hydroxyapatite to intermediate restorative material and Type II collagen powder to EBA. Of the reinforced ZOE cements, EBA is the strongest and the least soluble of all formulations. In literature, regarding clinical studies, a high success rate was reported when Super-EBA cement was used as root-end filling material. Super-EBA is currently considered more effective then amalgam for rootend filling. It could be considered a reliable material in the filling of molars’ root-end cavity.

Case report â&#x20AC;ş Mineral Trioxide Aggregate (MTA) Nowadays, MTA is the most adequate filling cement. MTA was developed as a new rootend filling material at Loma Linda University, California, USA. This cement is composed of calcium, silica and bismuth.

It has a long setting time, high pH and low compressive strength. It possesses some antibacterial and antifungal properties, depending on its powder-to-liquid ratio. MTA is a bioactive material that influences its surrounding environment. The sealing ability of MTA was investigated by many studies using different methodologies (68-72). They all reported good results with MTA when ranked with other materials. This may be because of its moisture tolerance and long setting time. Tissue response evaluated in vivo by intraosseous and subcutaneous implantation experiments73-77 found MTA to be well tolerated; it was also showed not to have an adverse affect on connective tissue microcirculation. MTA has the ability to encourage hard-tissue deposition, and the mechanism of action may have some similarity to that of calcium hydroxide (78).

Investigations of why MTA appears to induce cementogenesis found that the material seemed to offer a biologically active substrate for osteoblasts, allowing good adherence of the bone cells to the material, while also stimulating the production of cytokines (79).

Unlike a number of dental materials that are not moisturetolerant, MTA actually requires moisture to set. The MTA powder consists of fine hydrophilic particles. When mixed with sterile water, hydratation of the MTA powder results in a colloidal gel that solidifies into a hard structure. â&#x20AC;ş Glass ionomer cement and related materials In general, chemically cured glass ionomer cements are slow setting, difficult to handle in the awkward environs of the surgical wound and are susceptible to

blood/moisture contamination.

Although resin-modified glass ionomer cements are easier to handle and polymerization by light exposure allows controlled setting, the need for total dryness before placement remains an issue. Figure 2 shows root-end management step by step and figure 3 shows radiographic evidence of a periapical surgical procedure Microscope Microsurgical instruments and ultrasonic retrotips significantly improved the outcome of periradicular surgery when compared with traditional techniques (80). Such devices brought advantages for the rootend management (80).

Following the introduction of microsurgical principles in endodontic surgery, involving new techniques for preparation of rootend cavities, there has been a continuous search for enhanced visualization of the surgical field (81). The use of high quality magnification devices in dentistry is becoming more and more common, with the aim of improving the quality of treatment (82).

The use of surgical microscope was the next extension of the operating theory of enhanced light and magnification with surgical loupes. Many authors showed how this device provides the visual access necessary to perform microsurgical techniques with an excellent degree of confidence and accuracy (16, 17, 82-85).

Rubinstein and Kim (16) have reported very high success rate after periradicular surgery, advocating that the use of a surgical microscope might have been a decisive factor contributing to such an excellent outcome. Recently endoscopy was introduced in periradicular surgery: it has been reported that the endoscope may provide the surgeon with outstanding vision, and its use is easier than other magnification devices.

Two clinical prospective studies have recently been published in which the authors compared endoscope to magnification loupes as magnification devices for

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periradicular surgery. The best possible intra-operative visualization is necessary to maintain a high level of success.

Evaluation of success and failure A critical factor regarding endodontic surgery is the definition of success and failure criteria. Evaluation of success and failure following endodontic surgery may be limited to three modalities: clinical assessment, radiographic evaluation and, in some cases, histologic analysis.

Histologic analysis of the osseous tissue following periradicular surgery might be considered the most reliable technique to assess periradicular healing, but it is not routinely performed on patients.

Furthermore, even histologic appraisal of healing, like that of clinical and radiographic evaluation, can be categorized for the surgeon into success, questionable and failure (86). In accordance with other authors (86), it is better to consider that neither the presence nor the absence of clinical symptoms alone, as well as radiographic evaluation alone, should determine the success or failure of a case. Most studies on periradicular surgery used radiographic criteria as the major determinant of success or failure.

However, radiographic evaluation is subject to great variability and observer bias. Over the years, many authors (87-90) have proposed multiple criteria and radiographic classifications of healing. However, radiographic findings alone cannot give a true picture of biological wound healing response occurring at the resected root surface (23). Rud et al. (34) standardized and validated a radiographic classification system which was integrated with histologic findings and based on multiple-year evaluation. Subsequent studies (89) have supported the use of the classification of Rud et al in 1- to 4-year follow-up evaluations

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Taschieri S. et al.

(12, 40, 87). Nevertheless, some studies showed that there is no consistency on predictability between the radiographic picture and the histologic one (25,26,91. In 1987, Molven al. (87) proposed an adapted diagrammatic and radiographic representation of healing categories, showing root-end resection performed perpendicularly to the long axis of the root, as was performed in the present study.

Conversely, Rud et al. (89) proposed healing categories depicting radicular structure with an angled bevel at the root apex and showed radiographically some cases treated with this advocated technique.

Radiographic evaluation of root apex resected with an angled bevel creates problems in determining the nature of the tissue adjacent to the obliquely resected root surface; for this reason, when dealing with oblique root-end resections exposures from various projections are recommended. Radiographic criteria established for the complete healing group and the unsatisfactory (failure) group have been reported to possess a high degree of reliability after 1-year follow-up (17, 23, 88, 92). In 1996, Molven et al. (88) extended the observation time of an earlier study to 8 to 12 years of follow-up, and the findings supported the conclusion that cases clearly showing features of incomplete healing at the regular follow-up 1 year after surgery with no clinical signs and symptoms of inflammation can be regarded as successful. Jesslen et al. (82) determined that the validity of a 1year follow-up was predictable in more than 95% of the cases. An unpredictable long-term outcome has been observed in cases classified as uncertain after 1 year (87, 88). Molven et al, (87) in agreement with other authors (23, 86) scheduled the cases classified as uncertain healing for another regular follow-up 3 years later and then classified them as success or failure.

It is mandatory, at each scheduled clinical appointment, to record any evidence of signs and/or symptoms (23), following the guidelines of Gutmann & Harrison (86): clinical success, clinical questionable, and clinical failure. In accordance with

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other authors (23, 86), we considered that neither the presence nor the absence of clinical symptomology alone, as well as radiographic evaluation alone should determine the success or failure of a case.

Conclusion According to the current concepts of evidence-based health care (93), selection between alternative treatments is based on the assessment of their respective benefits and risks (6) from studies consistent with a high level of evidence. Such studies are those that conform to rigorous designs and well-defined methodology (6, 93, 94). The main benefit considered in evaluating the outcome of surgical treatment is the probability of healing (6 ).We believe that adherence to a strict endodontic surgical protocol, a minimally invasive surgical technique, a careful root-end preparation using contemporary techniques, visual magnification and proper materials, and a correct case selection might be key factors to the success of treatment.

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