JOS - European Journal of Oral Surgery

Official journal of the SocietĂ Italiana Specializzati in Chirurgia Odontostomatologica ed Orale Vol. 2 issue 3 december 2011 ISSN 2037-7525

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NEI CASI SEMPLICI E COMPLESSI UNA VISIONE INTERDISCIPLINARE IN ODONTOIATRIA

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

www.ejos.eu

Editor-in-chief

Publisher

Prof. Franco Santoro (Italy)

Editorial Director Prof. Carlo Maiorana (Italy)

Associate Editors 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. Nicholas Toscano (USA) Prof. Leonardo Trombelli (Italy) Dr. Istvan Urban (Hungary)

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ISSN: 2037-7525 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 Giampiero Gasperini

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In armonia con la natura

Vol. 2 issue 3 DECEMBER

page 65

Secure and effective stabilization of different sized autogenous bone grafts

page 71

J-shaped hip onlay graft as alternative to Le Fort I osteotomy for the treament of sagittal discrepancies in the maxillary atrophies

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

Editor-in-Chief

Prof. Franco Santoro SISCOO President

Editorial Dear colleagues, 2011 is ending and it’s time to strike the balance of one year of scientific activity.

The two courses organized in June and October, held respectively by Stefano Gracis and Jean Pierre Gardella were fully booked and highly appreciated by the members who attended them.

We have been working at the next year’s appointment with the national congress, September the 22nd in Milan.

Again, keynote speakers will report about state of the art in different areas as periodontology, implantology, oral surgery and oral pathology, with the goal to go on with the continuing education program we started with two years ago.

JOS is meeting with the favour of the clinicians and I want to take this opportunity to thank the editorial board for the terrific job done during the year.

We wish to continue the course of the society in the respect of a high scientific profile, since we really believe in the value of excellence.

To all the members of the society, on my side and on behalf of the whole board, a merry Christmas and a happy new year.

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Manuscript Preparation

Guidelines for Authors Manuscript Submission

Manuscripts can be uploaded in the “Manuscript Submission” section of the journal’s website http://www.ejos.eu or sent in a CD to the publisher: Ariesdue Srl via Airoldi, 11 - 22060 Carimate (Co) Italy e-mail: farma@ariesdue.it as a PC Word (doc) file with tables and figure legends at the end of the document. Figures should be supplied separately.

Submission Letter

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• Manuscripts should be typed in a 12-point font and double-spaced; their length should range from 6,000 to 18,000 digits for Case Reports and from 10,000 to 25,000 digits for Monographs. The number of visual components (images and tables) should not exceed 18.

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• Tables: Each table should be logically organized, typed on a separate page at the end of the manuscript, and numbered consecutively. Table title and notes should be typed on the same page.

• Legends: There should be an individual legend for each illustration. Figure legends should be typed as a group on a separate page at the end of the manuscript. Detailed captions are encouraged. For micro-photographs, specify original magnification and stain.

• References: References should be limited to those specifically referred to in the text, cited numerically, in order of appearance in the text and listed according to the following style (Vancouver style): Journals: 1. Del Fabbro M, Testori T, Francetti L, Taschieri S, Weinstein R. Systematic review of survival rates for immediately loaded dental implants. Int J Periodontics Restorative Dent 2006;26:249–264.

Books: 1. Tarnow DP, Cho S-C, Wallace SS, Froum SJ. Effect of surface morphology on implant survival in the grafted maxillary sinus. In: Jensen OT (ed). Bone Graft, ed 2. Chicago: Quintessence; 2006. p.223– 227.

Figures Figures should be supplied along with the manuscript but as separate high-resolution digital image files (jpg or tiff), and numbered consistently.

Publisher

Permissions and Waivers

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Monograph

Secure and effective stabilization of different sized autogenous bone grafts

Fouad Khoury* Herman Hidajat Privatklinik Schloss Schellenstein, Olsberg Germany *Department of Oral and Maxillofacial Surgery of the University of Muenster, Germany

Aim

Materials and Methods

Results

Conclusions

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A secure and solid fixation of the bone graft is an important criteria of success in augmentation procedures. Titanium screws are frequently oversized to fix small dimensioned bone grafts and may osseointegrate, thus leading to complications during screw removal. To solve these problems the new Microscrew® system was developed and investigated in this retrospective clinical study.

A total of 318 patients were treated in 2009 with autogenous bone grafting, according to the biological concept, in different indications from small to complex 3D bone defects. All in all, 486 autogenous bone grafts were stabilized with 923 Microscrews®, special self-tapping screws with a narrow diameter of 1 mm, made of medical stainless steel. Moreover, 287 implants were placed simultaneously and 449 implants were inserted with a delayed procedure after 3-4 months. All implants were loaded 3-4 months later.

All bone grafts achieved a good stability by the use of the Microscrews®.

An average of two Microscrews® was necessary to fix the bone grafts of different dimensions. Most of the grafted bone healed as expected and only some few complications occurred, such as infections (0.2%), limited graft exposure (1.2%), screw head exposure (5.3%), incomplete graft regeneration (1.8%) and bone resorption of more than 15% (2.4%). All implants could be placed according to the treatment plan. There was no graft failure, no soft tissue irritation, no screw fracture, no allergy, no screw aspiration, no metallosis and none osseointegration of the screw. After a follow up of two years all the implants were still functioning without any osseointegration disturbance.

The present study shows that the Microscrew® system is suitable for the stabilization of different sized bone grafts. Some drawbacks of titanium screws could be solved. The healing of the grafted bone and the surrounding soft tissue as well as the inserted implants occurred without any major disturbance.

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Key words: Graft stabilization, stainless steel screws, tissue healing.

Khoury F. and Hidajat H.

Introduction Patients with early loss of teeth frequently show localized or generalized bone defects of the alveolar ridge in the maxilla as well as in the mandible. Those defects may be a result of atrophy, dental traumata, accidents, pathologic resorption (imflammation, cyst formation), periodontal disease and previous surgeries (4). Missing teeth with important bone loss are associated with compromised mastication, swallowing, and speech functions as well as psychological conditions, thus leading to functional and aesthetic impairments which reduce the quality of life of the patient (6, 14, 20).

Replacement of the lost dentition by implant supported restorations offers the patient a predictable way to oral and thus social rehabilitation. Implant placement requires a sufficient bone volume, and in many cases it is necessary to increase the volume of the alveolar crest, both in width and height, due to the lack of bone, in order to obtain predictable and esthetic results as well as long term stability (2, 11).

It is possible to reconstruct the lost structure of hard and soft tissues with different surgical grafting techniques using autogenous, allogeneic or xenogeneic bone as well as alloplastic materials (18). Overall autologous bone has proved to be superior than other materials and still represents the gold standard in grafting procedures (8, 9, 13). A very important factor for successful autogenous bone augmentation is a good and solid fixation of the grafted bone to the recipient site. Most of the screws used to fix bone grafts are made of titanium and have an external screw diameter between 1.3 and 2 mm in the lengths from 6 to 18 mm (5, 19). The screw design is different for each manufacturer, but it can be broadly classified in self-drilling, self-tapped, pretapped and resorbable screws [5,13,16,19].

Screws with a diameter of 1.3 mm (the minimum length to prevent fractures) and higher are mostly oversized for the fixation of small bone grafts. There is the risk of fracturing the graft with the screw as well as injuring the simultaneously placed implant or the roots of the neighboring teeth. On the other hand, titanium screws with a diameter smaller than 1.5 mm may fracture (Fig. 1) or get damaged during the removal of the screw, and the titanium they are made of may osseointegrate (13).

Screws made from an alloy of manganese-chromiumCobalt-molybdenum (medical stainless steel) show better mechanical stability also in a small dimension. These screws were very popular in the 70s and 80s (Vironium, Vitallium, etc) in the traumatologic and orthopaedic surgery. With a deeper knowledge on osseointegration, they were later replaced by titanium. with the goal to leave them in the body after fracture healing. But in case of bone graft stabilization there is no interest with titanium because the screws have to be removed very often during implant placement.

For this indication the new Microscrew® (Stoma, Emmingen-Liptingen, Germany) made of medical stainless steel were developed in small diameter of 1 and 1.2 mm for stabilization of bone graft with different sizes.

We present here the results of a retrospective clinical study on patients treated with this screw in the year 2009.

The aim of this retrospective study is to investigate and to evaluate the stabilization of autogenous bone grafs with the Microscrew® System. Different bone grafting techniques, from the minimal invasive small augmentation

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fig. 1 Fractured titanium screw with 1.2 mm diameter during screw removal.

fig. 2 Microscrew® with 1 mm diameter and the special screw driver.

to 3D reconstruction of vertical defects, were performed.

Analysed criteria were handling of the Microscrew® System, safety device, stability, biological and clinical reaction of the screws, results of the bone grafting and removability of the screws as well as long term stability with a 2 years follow up.

Materials and methods The retrospective study evaluates all patients who were treated in the year 2009 with bone grafting procedures, according to the biological concept of bone grafting (8, 9), using the MicroSaw (7) and the new Microscrew® System.

A total of 318 patients (108 male and 210 female) aged from 17 to 88 years underwent autogenous bone graft in different indications starting with small periimplant exposed threads to complex 3D bone defects. In this period a total of 443 bone blocks, mostly harvested with the MicroSaw from the retromolar area of the mandible, and 43 cores, harvested with a trephine bur from the implant recipient site, were grafted and stabilized with a total number of 923 Microscrews®. These special screws are self-tapping and have an external diameter of 1 and 1.2 mm. The main screw is 1 mm; the 1.2 mm is the emergency screw. The screw length is available from 4 to 16 mm. A special screwdriver with a safety device is securing handling, preventing the uncontrolled looseness of the very small screw (Fig. 2).

The screws are made of a special medical stainless steel alloy, with main components manganese, chromium, cobalt

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Monograph

fig. 3 Implant insertion inside the contours: about half of the buccal bone is missing.

fig. 4 Reconstruction of the missing bone with the core harvested from the implant bed: a 1 mm diameter and 10 mm length Microscrew® is pressing the bone core on the implant surface giving an excellent stability.

fig. 5 Occlusal view demonstrating the thickness of the new buccal bone.

fig. 6 Clinical appearance after the restoration of the implants.

vertical grafts and 3D reconstructions (78 in the maxilla and 46 in the mandible). In 12 cases one screw was used to fix a replanted half bone block in its original site in the retromolar area. A total of 287 implants were placed simultaneously (Fig. 7) and 449 Implants were placed after a healing period of the grafted bone of 3-4 months. The implants were loaded 3-4 months later.

Most of the Microscrews® were removed at re-entry during implantation, or second stage surgery. In some rare cases the screws were left in the site eg. in the retromolar area or in cases where there was no need to raise a flap. fig. 7 Stabilization of a mini bone block with a Microscrew®.

and molybdenum. This gives the small diameter (1 mm) screws an excellent mechanical stability and the possibility to fix bone grafts of any sizes. Moreover, owing to the fact that the screws are not made of titanium, there is no osseointegration and so they can be removed very easily with no risk of screw fracture or wearing out the screw head. The small dimensioned screw head is not causing any soft tissue irritation and has less risk of screw exposure during the healing period.

In the present study the screws were used to stabilize 43 bone cores in combination with simultaneous implant placement (Fig. 3-6) to reconstruct 24 minor peri-implant bone defects in the maxilla and 19 in the mandible.

The screws were used for 307 lateral grafts with bone blocks (218 in the maxilla, 89 in the mandible) and 124

Results In the year 2009 a total number of 486 autogenous bone grafting procedures were performed in 318 patients according to the biological concept of bone grafting. A total of 923 Microscrews® were placed in order to fix and stabilize the grafted bone. An average of 2 Microscrews® were necessary to fix the bone blocks with different dimensions or to stabilize the cores. The smallest block fixed with the Microscrew® was 12 mm2. All bone blocks and cores had good stability thanks to the use of the screws. No bone blocks nor cores were damaged during the fixation procedure.

Most of the grafted bone healed as expected, so that all implants could be placed as it was planned before (Fig. 8-14). In only one case (0.2%) a primary infection

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Khoury F. and Hidajat H. process occurred with partial loss of the graft. No infection nor negative influences of the screws on the wound healing were observed. In no case an allergy against the material occurred. From the other site few complications occurred related to the bone grafting procedure: limited graft exposure due to partial flap necrosis or dehiscence

was observed in 5 cases (1.2%). After primary treatment with local desinfection (chlorhexidine rinsing 0.2% and chlorhexidine gel 0.1%), the exposed and infected bone areas were reduced, desinfected with antimicrobialphotodynamic therapy (3) and the wound was closed in double layer.

fig. 8 3D Bone reconstruction of the anterior part of the left maxilla: 2 bone blocks are stabilized with 3 screws. On the right maxilla the 3D bone reconstruction was performed with simultaneous implant placement.

fig. 9 After filling the space with particulate bone a third bone block is screwed on the occlusal side.

fig. 10 The clinical result three and a half months postoperatively: good healing of the grafted bone without any negative reaction around the screws.

fig. 11 Two implants were placed in the grafted and regenerated area in optimal conditions.

fig. 12 Clinical appearance of the restored implants 2 years postoperatively. fig. 13 Radiograph of the right anterior area 2 years postoperatively: good osseointegration of the implants. The screw was left in the bone since it caused no disturbance.

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fig. 14 Radiograph of the left grafted area of the maxilla 2 years postoperatively demonstrates the stability of the grafted bone and the good osseointegration of the implants.

Monograph Premature exposure of the screw head (mostly 8 weeks after surgery) occurred in 26 cases (5,3%) and had mostly no influence to the hard and soft tissue healing. There were no irritation of the mucosa and in just in 7 cases a little resorption of the bone was found, around the screw up to the second winding. Exposed screws were removed flapless without doing any surgery or sutures.

Incomplete regeneration of the grafted bone with soft tissue migration in the grafted area was observed in 9 cases (1.8%) and bone resorption of more than 15% occurred in 12 patients (2.4%). A limited re-augmentation was performed in these cases during implant placement.

Overall, neither damage of the screws nor of the surrounding tissues were observed: no screw fracture, no wearing of any screw heads, no screw aspiration, no metallosis and no osseointegration occurred, so that all screws were easily removed.

Each Microscrew® ensured at any time a good stability of the grafted bone and could always be removed as easy as they were placed. All Microscrews® that were left in the site showed a good and uneventful healing in every case so that there was no urgent need to remove the screw.

After a follow up of two years all the inserted implants were still functioning without any osseointegration disturbance.

Discussion and conclusion One of the most important factors of bone grafting procedures is the good stability of the graft, which is difficult to achieve with standard titanium screws in grafts of small dimension.

The results of this retrospective study confirmed that the use of small diameter (1 mm) screws made of medical stainless steel can be a good alternative for the fixation and stabilization of different sized bone grafts. Bone blocks with a length from 5 to 30 mm as well as small bone cores with 2 mm diameter showed a good fixation and stability with the 1 mm screws and the grafting procedure showed similar good results as with titanium screws. In some cases there is not enough space on the recipient site between the implant and the neighboring tooth when cores or small blocks are grafted with simultaneous implant insertion in a limited area, as for example in a single tooth implantation. Screws made of titanium or resorbable screws made of PLLA are mostly 1.5 mm or 2 mm and higher in diameter (13): with these diameters the screws are oversized and could not be used in these indications due to the risk of fracturing the graft, or injuring anatomical structures or neighboring teeth.

In such situation the 1 mm diameter screw can simplify these difficulties and give more security in prevention of complications (Fig. 7). So far no foreign body reaction was observed.

In the literature there are not many clinical studies or evaluations of dental osteosynthesis screws in autogenous bone augmentation. Fracture of titanium screws is reported, especially at the time of screw removal if the screws were osseointegrated (13). Microscrews® are not made of titanium but of medical stainless steel and for this reason the risk of screw fracture is highly minimized. In the present study no screw fracture was observed. There were no osseointegration of the screws and the screw removal was as easy as the placement (Fig. 15, 16).

It is mentioned as a drawback that there is a need of a second surgery for screw removal (13), but this is not a big disadvantage in implant surgery, because usually after augmentation and implantation there is another surgical intervention where screws can be removed during implantation or second stage surgery. So there is no discomfort to the patient and no extra intervention beside those planned before. Beside that, Microscrews® have no urgent need to be removed and could be left in the site, as it happened in some cases. No bone overgrow on the Microscrews® was observed at all as it is reported in the literature, and this makes the removal of the screw more difficult (13). This is possible thanks to the alloy used and the design of the screw head, with a square drive which is not flat.

The Microscrews® are self-tapped screws and come along with a corresponding drill bur with marks for the depth. The fixation of the graft was achieved in each case and showed excellent stability at any time until the healing of the graft and the removal of the screws. A special screwdriver mounted on contra-angle is helpful in areas of difficult access for optimal stabilization of the Microscrew® (Fig. 17, 18). The literature reports of the fixation measured by pullout strength showed that there is no difference between self-tapped and pretapped screws of equal diameter: both showed similar values even after insertion and removal in the same hole for several times (5). Similar results are reported by Koranyi et al. and Schatzker et al.

(10, 15). Other studies showed a greater holding strength

fig. 15 3D reconstruction with tunnel approach: The 2 bone blocks were stabilized with 5 Microscrews®.

fig. 16 Clinical appearance 4 months postoperatively: 2 implants inserted in the grafted/regenerated bone.

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Khoury F. and Hidajat H.

References

fig. 17 Screw driver mounted on contra angle allows the insertion of the screw in difficult situation.

fig. 18 3D reconstruction on the posterior mandible with simultaneous implant insertion.

in the thin maxillo-facial bone for self-tapped screws than for pretapped screws. And therefore self-tapped screws are more commonly used in thin bone such as that found in the maxilla (1, 12, 19). So there are no advantages with the pretapped screws, but some drawbacks such as an additional step of tapping the hole, more instruments and complex handling.

Another important feature of the Microscrew® System is the special screwdriver with a safety device. The Microscrews® are inserted at the top of the screwdriver with the clamping device. In this way the screw is fixed to the screwdriver, thus preventing the screw dropping down to the ground or the patient´s mouth which could be aspirated or swallowed up by the patient. This complication never happened in the presented study. Aspiration and ingestion of teeth and dental instruments is a well known complication which can happen during any treatment (17).

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1. Bahr W. Pretapped and self-tapping screws in the human midface. Torque measurements and bone screw interface. Int J Oral Maxillofac Surg 1990;19:51-53.

2. Buser D, Dula K, Hess D, Hirt HP, Belser UC. Localized ridge augmentation with autografts and barrier membranes. Periodontol 2000 1999;19:151-163.

3. Dortbudak O, Haas R, Mailath-Pokorny G. Effect of low-power laser irradiation on bony implant sites. Clin Oral Implants Res 2002;13:288-292.

4. Esposito M, Grusovin MG, Coulthard P, Worthington HV. The efficacy of various bone augmentation procedures for dental implants: a Cochrane systematic review of randomized controlled clinical trials. Int J Oral Maxillofac Implants 2006;21:696-710.

5. Foley WL, Frost DE, Tucker MR. The effect of repetitive screw hole use on the retentive strength of pretapped and self-tapped screws. J Oral Maxillofac Surg 1990;48:264267.

6. Gonzalez-Garcia R, Naval-Gias L, Munoz-Guerra MF, Sastre-Perez J, Rodriguez-Campo FJ, Gil-Diez-Usandizaga JL. Preprosthetic and implantological surgery in patients with severe maxillary atrophy. Med Oral Patol Oral Cir Bucal 2005;10:343-354.

7. Khoury F. Augmentation of the sinus floor with mandibular bone block and simultaneous implantation: a 6-year clinical investigation. Int J Oral Maxillofac Implants 1999;14:557-564.

8. Khoury F, Khoury Ch. Mandibular bone block grafts; instrumentation, harvesting technique and application. J Par Impl Orale 2006; 25: 15-24.

9. Khoury F, Antoun H, Missika P. (Editsg). Bone Augmentation in Oral Implantology.

Surrey, UK: Quintessence Publishing Co, Ltd, 2007.

10. Koranyi E, Bowman CE, Knecht CD, Janssen M. Holding power of orthopedic screws in bone. Clin Orthop Relat Res 1970;72:283-286.

11. Maestre-Ferrin L, Boronat-Lopez A, Penarrocha-Diago M, Penarrocha-Diago M. Augmentation procedures for deficient edentulous ridges, using onlay autologous grafts: an update. Med Oral Patol Oral Cir Bucal 2009;14:e402-407.

12. Phillips JH, Rahn BA. Comparison of compression and torque measurements of selftapping and pretapped screws. Plast Reconstr Surg 1989;83:447-458.

13. Quereshy FA, Dhaliwal HS, El SA, Horan MP, Dhaliwal SS. Resorbable screw fixation for cortical onlay bone grafting: a pilot study with preliminary results. J Oral Maxillofac Surg 68:2497-2502.

14. Raes F, Cooper LF, Tarrida LG, Vandromme H, De Bruyn H. A case-control study assessing oral-health-related quality of life after immediately loaded single implants in healed alveolar ridges or extraction sockets. Clin Oral Implants Res 2011 Apr 19. doi: 10.1111/j.1600-0501.2011.02178.x. [Epub ahead of print] 15. Schatzker J, Sanderson R, Murnaghan JP. The holding power of orthopedic screws in vivo. Clin Orthop Relat Res 1975;115-126.

16. Sowden D, Schmitz JP. AO self-drilling and self-tapping screws in rat calvarial bone: an ultrastructural study of the implant interface. J Oral Maxillofac Surg 2002;60:294299.

17. Tiwana KK, Morton T, Tiwana PS. Aspiration and ingestion in dental practice: a 10-year institutional review. J Am Dent Assoc 2004;135:1287-1291.

18. Walker DA. Mandibular distraction osteogenesis for endosseous dental implants. J Can Dent Assoc 2005;71:171-175.

19. You ZH, Bell WH, Schneiderman ED, Ashman RB. Biomechanical properties of small bone screws. J Oral Maxillofac Surg 1994;52:1293-1302.

20. Zosky JG. Use of autogenous bone graft from the iliac crest to restore an atrophic maxilla with implant-retained prosthesis. J Can Dent Assoc 2006;72:521-524.

Case report

J-shaped hip onlay graft as alternative to Le Fort I osteotomy for the treament of sagittal discrepancies in the maxillary atrophies C. Maiorana* G. B. Grossi** S. Speroni*** A. E. Borgonovo*** E. Stoffella*** M. Beretta**** Dental Clinic Fondazione IRCCS CĂ Granda, University of Milan, Milan, Italy *Head and Chair, Oral Surgery and Dept. of Implant Dentistry **Head, Dept. of Implant Dentistry ***Attending Doctor, Dept. of Implant Dentistry ****Clinical Assistant Professor, Dept. of Implant Dentistry

Background

Conclusion

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The treatment of the severely resorbed maxilla is very challenging with regards to an implant supported rehabilitation. Very often, an intermaxillary sagittal discrepancy occurs, coupled to an increased vertical ridge resorption, and a class III-like situation can be appreciated. In such cases, the surgical treatment to restore the correct intermaxillary relationship is represented by a Le Fort I osteotomy with interpositional autogenous blocks. Thanks to this procedure, both the sagittal and the vertical intermaxillary relationships can be restored. Nevertheless, Le Fort I appoach is quite aggressive if we consider that most of the patients suitable for such a treatment are senior ones. For this reason, an alternative procedure can be chosen in order to reduce postoperative morbidity.

The described technique, the J-shaped onlay graft, can lead to a satisfactory restoration of the intermaxillary relationship in sight of a rehabilitation with implants and fixed or swivel lock prostheses.

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Key words Intermaxillary sagittal discrepancy; vertical ridge resorption; Le Fort I osteotomy; J-shaped onlay graft.

Maiorana C. et al.

Introduction Further to the loss of teeth, alveolar ridge resorption leads to a combined vertical and horizontal reduction of the bone support, and at the same time increased maxillary sinus pneumatization.

The subsequent alteration of the intermaxillary relationship, once a class VI atrophy (1) has established, determines a class IIIlike situation which is not compatible with a prosthetically guided implant rehabilitation. In those cases, bone augmentation procedures, by means of extraoral bone graft harvested from the hip or the calvaria, are mandatory in order to rebuild an adequate amount of bone as well as a proper intermaxillary relationship.

Usually, the standard technique to accomplish these two requisites is represented by Le Fort I maxillary osteotomy with interpositional bone blocks, that allow to get the double goal of recreating the ridge and restoring a class I intermaxillary relationship (2, 3, 4). In spite of the possibility to recreate the maxillary anatomy, Le Fort I remains a quite aggressive procedure when it is planned in a senior patient, because of a higher morbidity if compared to other bone augmentation techniques.

An alternative to the Le Fort I osteotomy in case of alteration of the intermaxillary relationship can be represented by a variant of the classic onlay graft technique, by modifying the shape of the corticocancellous bone blocks harvested from the hip, which assume the so called “J shape”. The blocks, modelled and adapted to the recipient atrophic ridge, can increase the horizontal ridge and vertical dimension and reduce or eliminate the class III-like sagittal discrepancy.

Case report A 58 year old male patient underwent a first consultation at the Department of Implant Dentistry, Dental Clinic, asking for an implant-supported prosthetic restoration. The extraoral examination (Fig. 1, 2) showed a lack of vertical dimension and an apparent class III, in a totally edentulous patient. The intraoral examination (Fig. 3, 4) revealed an extreme horizontal and vertical resorption of the maxillary ridge, and again a class

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III intermaxillary relationship. The radiographic examination, carried out with a panorex and a CT scan (Fig. 5, 6, 7) showed a knife edge ridge in the front area and a flat ridge in the back, with less than 3 mm of residual alveolar bone.

The decision to perform a Le Fort I osteotomy plus interpositional blocks from the hip was taken and proposed to the patient, who refused the treatment asking for a less invasive technique.

An onlay graft procedure with J shaped blocks was then considered and again proposed to the patient who accepted the treatment plan.

At the time of surgery, under general anaesthesia (Fig. 8) the harvesting procedure from the hip was performed in order to get a corticocancellous block, 6 cm in length and 1.5 in height.

The block was then modelled and J shaped corticocancellous blocks were obtained.

A bilateral sinus elevation procedure was performed and the subantral cavity filled with a 1:1 ratio mix of anorganic bovine bone granules (Bio-Oss®, Geistlich Co.; Wolhusen,

Switzerland) and autogenous bone marrow (Fig. 9, 10). The J-shaped blocks were then fixed to the atrophic ridge with transcortical screws (Fig. 11, 12) and covered with a thin layer of anorganic bovine bone granules and a collagen membrane to limit the graft’s resorption due to remodelling (Fig. 13, 14) (5, 6). The postoperative X rays show the bone augmentation obtained (Fig. 15, 16).

Four months later, under local anaesthesia, the screws were removed (Fig. 17), then 8 Astratech implants (Osseospeed®, Astra, Sweden) (Fig. 18) were placed in the maxilla and 6 in the interforaminal mandibular area (Fig. 19).

The efficacy of the anorganic bovine bone coverage technique is proved by the absence of resorption around the screws.

After waiting for osseointegration (6 months), implants uncovering took place with a contemporary reconstruction of the surrounding soft tissues. The soft tissue management was achieved by means of an apical repositioning flap in the maxilla and

fig. 1, 2. Frontal and lateral views showing the alteration of the intermaxillary relationship, with lack of vertical dimension and an apparent class III.

fig. 3, 4. The intraoral examination revealed an extreme horizontal and vertical resorption of the maxillary ridge.

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fig. 5, 6, 7. The panoramic exam and CT scan cross sections show a knife edge ridge in the front area and a flat ridge in the back with less than 3 mm of residual alveolar bone.

fig. 8. Intraoral view of the upper maxillary ridge exposed with a T full thickness incision.

fig. 9, 10. Sinus lift technique according to Boyne and James; the subantral cavity is filled with a 1.1 ratio mix of anorganic bovine bone granules and autogenous bone marrow.

fig. 11, 12. The J- shaped blocks are fixed to the atrophic ridge with transcortical screws.

fig. 13, 14. The anorganic bovine bone granules and the collagen membrane are placed to cover and protect the graft, and so to limit physiologic bone resorption.

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fig. 15, 16. Panoramic and lateral radiographic exams showing the bone augmentation obtained.

fig. 17. Cortical screws removal during the second surgical phase, 6 months after the bone graft procedure.

fig. 18, 19. Eight and six implants (Astratech Osseospeed速, Astra, Sweden) are positioned in the upper maxilla and in the mandible at the same time.

fig. 20, 21. Soft tissue management six months after the implant placement. An apical repositioning flap is performed in the maxilla and two free gingival grafts in the lower jaw.

fig. 22, 23. Frontal and lateral pictures taken 4 years after surgery showing the correction of the residual horizontal intermaxillary discrepancy using a swivel lock prostheses.

two free gingival grafts in the lower jaw (Fig. 20, 21).

One month after the uncovering

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fig. 24. Panoramic exams after 48 months shows the marginal bone level stability.

surgery, the prosthetic rehabilitation took place. After examining the intermaxillary relationship on an

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articulator, and analysing the upper lip support, a swivel lock prosthesis was chosen to correct the residual

Case report horizontal intermaxillary discrepancy (Fig. 22).

The final result shows a good aesthetic appearance and the panorex (Fig. 24) taken 48 months after loading allows to appreciate the marginal bone level stability.

Conclusion The J-shaped technique allows to overcome intermaxillary discrepancy problems in severe maxillary atrophies having the postoperative morbidity reduced when compared to a Le Fort I osteotomy, even though a perfect class I relationship restoration largely depends on the amount of bone to be replaced.

References 1. Cawood JI, Howell RA. A classification of the edentulous jaws. Int J Oral Maxillofac Surg 1988;17(4):232-6.

2. Sailer HF. A new method of inserting endosseous implants in totally atrophic maxillae. J Craniomaxillofac Surg 1989;17(7):299-305.

3. Araujo A, Schendel SA, Wolford LM, Epker BN. Total maxillary advancement with and without bone grafting. J Oral Surg, 1978;36(11):849-58.

4. Maiorana C, Speroni S, Beretta M, Salina S, Santoro F. Individual skeletal models and preoperative simulation in advanced osseointegration: a case report. Int J Periodontics Restorative Dent 2003;23(6):615-20.

5. Maiorana C, Beretta M, Salina S, Santoro F. Reduction of autogenous bone graft resorption by means of bio-oss coverage: a prospective study. Int J Periodontics Restorative Dent 2005;25(1):19-25.

6. Maiorana C, Beretta M, Battista Grossi G, Santoro F, Scott Herford A, Nagursky H, Cicci첫 M. Histomorphometric evaluation of anorganic bovine bone coverage to reduce autogenous grafts resorption: preliminary results. Open Dent J 2011;25(5):71-8.

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