Article fr kit JOMI by Kei Lim

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Int. J. Oral Maxillofac. Surg. 2015; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2015.11.003, available online at http://www.sciencedirect.com

Clinical Paper Dental Implants

Removal of dental implants: review of five different techniques

Q1 Z. Stajcˇic´ 1, L. Stojcˇev Stajcˇic´2, M. Kalanovic´2, A. Ðinic´2, N. Divekar1, M. Rodic´1 1 Dental/Medical Clinic of Maxillofacial Surgery ‘‘Beograd-Centar’’, Belgrade, Serbia; 2 Clinic of Oral Surgery, School of Dentistry, University of Belgrade, Belgrade, Serbia

Z. Stajcˇic´ L. Stojcˇev Stajcˇic´, M. Kalanovic´, A. Ðinic´, N. Divekar, M. Rodic´: Removal of dental implants: review of five different techniques. Int. J. Oral Maxillofac. Surg. 2015; xxx: xxx–xxx. # 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Abstract. The aims of this study were to review five different explantation techniques for the removal of failing implants and to propose a practical clinical protocol. During a 10-year period, 95 implants were explanted from 81 patients. Explantation techniques used were the bur–forceps (BF), neo bur–elevator–forceps (hBEF), trephine drill (TD), high torque wrench (HTW), and scalpel–forceps (SF) techniques. The following parameters were analyzed: indications for explanation, site of implantation, and the type, diameter, and length of the implant removed. The most frequent indications for implant removal were peri-implantitis (n = 37) and crestal bone loss (n = 48). The posterior maxilla was the most frequent site of implant removal (n = 48). The longer implants were more frequently removed (n = 78). The majority of implants were removed after 1 year in function (n = 69). The BF/hBEF and SF techniques were found to be the most efficient. Explantation techniques appeared to be successful for the removal of failing implants. The BF/ hBEF and SF techniques demonstrated 100% success. The hBEF technique enabled safe insertion of a new implant in the same explantation site. The HTW technique appeared to be the most elegant technique with the highest predictability for insertion of another implant. An explantation protocol is proposed.

Q2 The current literature provides ample data

on the high success rates of dental implant treatment, which range from 90% to 97%. Failing implants are usually removed either because of progressive bone loss due to a peri-implant infection,1,2 frequently associated with occlusal overload ,3 or due to placement in aesthetically unacceptable locations.4 Explantation is also performed on osseointegrated orthodontic implants following the termination 0901-5027/000001+08

of the orthodontic treatment.5 Furthermore, implants associated with a good bony and soft tissue condition are occasionally removed in psychologically unstable patients.6 Different techniques for dental implant removal have been proposed in the literature, such as the use of thin burs or a trephine drill at low speed under water cooling,6–8 the use of an electro-surgery unit to cause thermo-necrosis of the bone

Key words: dental implant explantation; dental implant failure; peri-implantitis; dental implant complications. Accepted for publication 3 November 2015

and subsequent weakening of the bone– implant interface,9,10 and laser-assisted explantation,11 as well as a removal torque procedure.12,13 Available data on explantation techniques appear to be inconsistent, therefore there is no reported unique treatment protocol for the successful and least traumatic removal of dental implants. The employment of less traumatic manoeuvres seems to be required to create minimal residual

Please cite this article in press as: Stajcˇic´ Z, et al. Removal of dental implants: review of five different techniques, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.11.003

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bony defects and spare the soft tissues. Ideally, the explantation procedure should be followed either by the installation of another implant or by guided bone regeneration (GBR), or both at the same sitting, when indicated. The aim of this study was to review five different explantation techniques based on the authors’ clinical material, in order to describe their advantages and disadvantages and to offer a practical clinical protocol for the explantation of failing implants. Materials and methods

In this retrospective cohort study, the dental records of 112 patients of both sexes who had been subjected to the removal of a total of 129 dental implants over a 10year period (2003–2013) were examined. Seventy patients were referrals. The dental records of 31 patients from whom 34 implants were removed were excluded from the study on the basis of the following criteria: accidental removal of the implant (1) at the time of the cover screw being replaced by the healing abutment (n = 6); (2) with the tightening force of 35 N cm applied for mounting the abutment (n = 13); (3) as a result of failing osseointegration without symptoms or signs of peri-implantitis at routine follow-up (n = 8); (4) becoming loose in the infected bone (n = 3). All other failing implants, irrespective of the cause, were removed using dental forceps and rotational and/or rocking movements only (n = 4). The dental records of the remaining 81 patients with a total of 95 implants removed were analyzed with respect to the effectiveness of the surgical techniques applied, indications for explantation, the anatomical distribution of the implants removed, and the implant types, diameters, and lengths. Surgical techniques applied in the present study are described as the bur–forceps technique (BF), the neo bur–elevator–forceps technique (hBEF), the trephine drill technique (TD), the high torque wrench technique (HTW), and the scalpel–forceps technique (SF). Apart from the SF technique, all techniques were used only for implants indicated for removal with a minimum of 1/3 of the threads and that were well osseointegrated without any mobility. Implants that were removed accidently while replacing a cover screw with a healing abutment or applying a tightening force of 30–35 N cm for mounting the abutments, or those failing osseointegration or becoming loose in the infected bone, as well as those removed

using dental forceps and rotational and/or rocking movements only, were excluded from this study. The bur–forceps technique (BF)

After elevation of a mucoperiosteal flap, a small sized round and/or fissure bur (Nos. 3–4) is used to remove the bone, usually from the facial aspect down to the apex of the implant, taking care to preserve the lingual cortex and as much of the bone as possible mesially and distally (Fig. 1). If bone resorption is found on the lingual side (this occurred in two cases), with the facial cortex intact, then the bony defect is deepened on the lingual side sparing the facial cortex. The implant is then grasped with the dental forceps and an attempt made to remove it by rotational and slight rocking movements, similar to tooth extraction. If this is not feasible, more bone is drilled out until it is possible to either unwind it or luxate it towards the boneremoved region, thus creating a three-wall bony defect. The neo bur–elevator–forceps technique (hBEF)

This technique commences with the removal of bone mesially and distally from

Fig. 1. Failing implants in the posterior maxilla removed using the bur–forceps (BF) technique. (A) Preoperative condition with the bone loss affecting the buccal aspect of the implants. (B) Three-sided bone defects following explantation.

the implant, aiming towards the apex. Round and/or fissure burs (No. 1) are used, with copious running saline, trying to maintain a close distance to the implant surfaces (Fig. 2A). The implant head is grasped with the corresponding tooth/Lyer forceps and turned clockwise and anti- Q3 clockwise. When resistant to such attempted movements, a thin straight elevator (Couplands elevator No. 3) is placed into the mesial and distal crevices, intermittently applying small gentle rotating movements similar to those used for the extraction of buried roots, until the implant is noted to be slightly tilted to one side (Fig. 2B). Then, the elevator is placed into the crevice on the contralateral side and similar movements performed. The implant head is then grasped with dental extraction forceps and gentle rocking movements applied, pushing it mesially and distally only, thus preserving both the facial and the lingual cortical plates (Fig. 2B). When little resistance is felt, the implant is removed with a final anticlockwise rotation leaving an ovoid defect (Fig. 2C). The trephine drill technique (TD)

An appropriate trephine drill with a diameter and length corresponding to the size of the implant to be removed is selected (Fig. 3A). The healing abutment or abutment/crown is unscrewed and a mucoperiosteal flap raised if necessary. The trephine drill is sunk over the implant into the bone using low speed 50–80 rpm drilling and light pressure with running saline cooling. A hole is drilled taking care that the trephine has been sunk to the exact depth by controlling the outside rings on the drill. For implant systems that do not provide a guiding cylinder/pin, a healing abutment of smallest emergence profile diameter is mounted before using the trephine (Fig. 3B). For Straumann Standard Q4 and Standard Plus implants, the polished neck is reduced with a high-speed diamond drill to correspond to the diameter of the guided cylinder. In the event that the implant is still firm after the trephine has been lifted (in cases of insufficient drilling depth), a Couplands elevator is placed into the empty space and lightly twisted to break the bony connections, enabling easy removal of the implant using the fingertips. The high torque wrench technique (HTW)

For the patients included in this study, the Neo Fixture Remover Kit (Neobiotech Co., Korea) was used for this technique.

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Fig. 3. The trephine drill (TD) technique. (A) The trephine drill is selected to match the diameter of the failing implant. (B) Before using the trephine drill for the removal of a Straumann Standard or Standard Plus implant, the polished neck is trimmed with a diamond bur to the size of the implant body diameter.

Fig. 2. Three failing implants in the mandible. The central implant was planned for implantoplasty to support the provisional bridge, whereas the lateral ones were indicated for removal. The distant one was removed using the high torque wrench (HTW) technique, whereas the mesial implant with the fractured neck was removed with the neo bur–elevator–forceps (hBEF) technique. (A) The distal implant was removed and a new one inserted. The bone was removed mesially and distally around the mesial implant using a No. 1 round bur and fissure burs. (B) A No. 3 Couplands elevator was placed into the bone crevice on both sides intermittently and slight rotational movements applied until the implant was tilted. (C) The defect was of an ovoid shape with well preserved facial and lingual cortices ready for the insertion of a new implant (not shown).

The compatibility list was consulted first to determine the correct dimension of the fixture remover screw and the implant remover to fit to the implant chamber and outer diameter, respectively. The procedure commences with the removal of the cover screw or the abutment of the implant to be removed. The fixture remover screw is inserted clockwise (Fig. 4A) and tightened using the torque wrench with a torque of 50 N cm (Fig. 4B). The fixture remover screw, which features a specific thread design at the apical tip, is attached to the receiving implant chamber, while the opposite end has a fixed constant diameter. The next instrument, named the implant remover, is manually screwed onto the free end of the fixture remover screw in an anticlockwise direction (Fig. 4C). Once the implant remover has been seated, the dynamometric ratchet is set in an anti-clockwise direction and force applied to unwind the implant (Fig. 4D). It usually takes a few seconds until less resistance is felt. During this time, the implant and the surrounding bone are cooled using saline, since an increase in bone temperature is expected as a result of high friction (300– 500 N cm). After one to two turns with the torque wrench, almost no resistance is usually felt and the implant is manually

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Fig. 4. The high torque wrench (HTW) technique. (A) The fixture remover screw is mounted onto the failing implant manually. (B) The fixture screw is tightened with the high torque wrench, with a torque of 50 N cm, clockwise. (C) The implant remover is manually screwed onto the free end of the fixture remover screw in an anti-clockwise direction. (D) The wrench is set and the force applied in an anti-clockwise direction. (E) After 1–2 turns with the torque wrench, the implant is manually unscrewed.

unscrewed (Fig. 4E). If the implant does not become loose despite maximal torque applied, the implant remover is temporarily removed, and a No. 1 round bur used to remove the bone around the implant neck down to the second or third thread; the implant remover is then mounted again, applying sufficient torque until the implant becomes loose. Following the termination of the procedure, when successful, the implant is removed together with the fixture remover screw and the implant remover. The implant remover and the fixture remover screw are dismantled from the removed implant by simultaneous use of the torque wrench and the pliers, firstly turning the implant remover clockwise and secondly the fixture remover screw anti-clockwise. Re-use of the fixture remover screw and implant remover is possible with caution. The fixture remover screw may be re-used once or twice provided that a low unwindQ5 ing force has been applied. The implant remover, however, may be re-used more frequently, until the beaks become blunt. The scalpel–forceps technique (SF)

This technique was used only for implants with an old-fashioned blade design, as well as ‘basal osseointegrated implants’ (BOI),14 which are supposed to be anchored to the bone by a combination of osseointegration and connective fibrous

tissue bands, formerly defined as ‘fibroosseointegration’.15 The Linkow-type blade vent implant head is grasped with dental forceps and a luxation movement started with constant pulling.16 The scalpel is used to sever the connective tissue bands all around the implant. This may take some time, and despite wobbling and mobility, it is not possible to extract the implant until the last connective tissue band is released (Fig. 5A–C). For BOI, in the event that the horizontal part is bent, this must first be straightened with Lyer forceps and the implant head grasped with dental forceps with one hand. The scalpel in the other hand is used to sever the connective tissue while the implant is pulled constantly towards the lateral aspect of the jaw until the least resistance is felt. Results

A total of 95 implants were removed. Of these 95 implants, 53 were removed from the maxilla and 42 from the mandible. The indications for explantation were recurrent peri-implantitis not responding to treatment in 37 cases, crestal bone loss in 48 cases, neurosensory deficit of the inferior alveolar nerve as a result of compression in two cases, chronic periodontitis of the neighbouring teeth affecting the implant in five cases, implant fracture in two cases, and osteomyelitis in one case. The ana-

tomical distribution of the implants removed and the implant types, diameters, and lengths are described in Table 1. The Q6 posterior maxilla was the most frequent site of implant removal (n = 48), followed by the posterior mandible (n = 35). The majority of implants (n = 69) were removed after a minimum of 1 year in function. The longer implants were more frequently removed (n = 78) when compared to implants with a length of less than 8 mm (n = 17). It was possible to insert another implant at the same sitting in 23 explantation sites. Of these, 17 were inserted following the use of the HTW technique, five following the hBEF technique, and one following the TD technique. Of the 23 inserted implants, two failed osseointegration (after 4 and 6 months respectively); new implants were inserted and are still in function 2 years after placement. The remaining 72 explantation sites that were left open healed uneventfully. Explantation techniques according to the implant type and diameter are shown in Table 2. With regard to the efficacy of the techniques applied, the BF/hBEF techniques proved to be the most efficient (Table 3). The TD technique failed in two out of 19 attempts, whereas the HTW technique failed in five out of 32 cases. The hBEF technique proved successful even when TD and HTW failed (seven cases). The time scale of the use of

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Fig. 5. The scalpel–forceps (SF) technique. (A) Preoperative radiographic image of a failing Linkow-type blade implant in the upper jaw. (B) The implant-supported crown is grasped with the dental forceps after the fibrous bands around the implants have been severed with a scalpel. (C) The removed implant with the soft tissue capsule around it.

the implant removal techniques is summarized in Table 4. Discussion

The number of implants placed has increased dramatically over the last decade, thus the number of failures is expected to grow accordingly. This necessitates the involvement of the implant industry in providing the required equipment, as well as implant surgeons to develop new surgical techniques that can be used not only to remove a failing implant with very little damage, but also to insert another one at the same implant site when indicated. Changes in the implant industry have led us to modify our surgical technique dramatically (Table 4). Until 2010, BF/

hBEF and TD were used almost exclusively for the removal of failing implants, whereas within the last 3 years, the HTW technique has become the first choice treatment (78%) because of its simplicity and elegance, as well as predictable insertion of another implant at the same osteotomy site. It has been reported that the following occurrences can contribute to an increase in the implant failure rate: a low insertion torque of implants that are planned to be loaded immediately or early, an inexperienced surgeon inserting the implants, implant insertion in the maxilla, implant insertion in the posterior regions of the jaws, implants in heavy smokers, implant insertion in bone quality of types III and IV, implant insertion in places with small bone volumes, the use of shorter length implants, a greater number of implants placed per patient, lack of initial implant stability, use of cylindrical (non-threaded) implants and prosthetic rehabilitation with implant-supported overdentures, the use of the non-submerged technique, immediate loading, and implant insertion in fresh extraction sockets, as well as the use of smaller diameter implants.17 However, crestal bone loss and peri-implantitis were the most frequent causes of implant removal in the present study, although the sample was too small for definite conclusions to be drawn. This study showed that explantation techniques are generally efficient, with a low failure rate; BF/hBEF proved to be 100% successful and can be recommended as a safe and reliable technique should others fail. The SF technique was applied for old-fashioned blade vent implants, which have not been in use in the last three decades, as well as for BOI, which have been employed sporadically; thus it is expected that this technique will be used rarely and is not a matter of further discussion. Irrespective of the efficacy of explantation techniques, two patients with neurosensory deficit of the inferior alveolar nerve did not improve following successful removal of the implants causing symptoms. When the BF, hBEF, TD, and HTW techniques are compared on the basis of technical requirements, the time required for their execution, and on patient and surgeon compliance, it should be emphasized that the BF and hBEF techniques proved to be the most reliable, versatile, and predictable; however, they are not well accepted by patients because of the drilling noise, force applied, and the length of time needed. The HTW and

TD techniques have been shown to be quick, elegant, and well accepted by both patients and surgeons; however they have Q7 limitations that need further elaboration. With regard to the HTW technique, specially designed instruments or kits are needed, which vary from company to company (the Straumann 48 h explantation device (Straumann), the Neo Fixture Remover Kit (Neobiotech), BTI Implant Extraction System (Biotechnology Institute S.L.), Implant Retrieval Tool (Nobel Biocare)). In essence, two types of instrument are used, one of a screw-type to engage the implant and the other a hightorque dynamometric ratchet to unwind the implant. These kits have recently been brought to the dental market and therefore data on their use in the literature are scarce.12 The use of removal torque for explantation of orthodontic mini-implants has already been documented in the literature.13,18,19 Since orthodontic miniimplants have a diameter not larger than 2 mm and length of 7–17 mm, the reported removal torque values have been smaller than those required for unscrewing dental implants of a standard diameter and length.13,18 A more recent retrospective longitudinal study described the Biotechnology Institute extraction kit for explantation, which consists of a wrench that allows a 200 N cm counter-torque force, an internal connection extractor, an extractor for external connection, and a set of ratchet handle extension pieces. This technique appears to be the least traumatic and biologically acceptable, since after it has been used there is almost no bony defect left except an empty implant bed preparation site.12 These findings correlate with the results found in the present study. However, HTW has its limitations. Open systems such as the Neobiotech Fixture Remover Kit, which was used for patients included in the present study, despite versatility and a compatibility list, lack a perfect fit for less known implants; in such cases, trial-and-error often has to be used to determine the corresponding diameter of the fixture remover screw. Fracture of the fixture remover screw is Q8 likely should high torque be applied (Fig. 6A–C). In the case of vertical implant fracture during installation when excessive torque is applied (as has happened in our patients using narrow platform NobelReplace or NobelActive implants), this explantation technique has not been feasible. With regard to osseointegrated Straumann Standard or Straumann Standard Plus implants in the mandible, the implant remover may dig

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Q13 Table 1. Characteristics of implants removed and the anatomical site of insertion according to the type of implant and the implant diameter.

Implant

Implant type and diametera Length 8 mm Narrow diameter Straumann Standard Bone level Nobel Biocare Replace Select Tapered NobelActive Regular diameter Straumann Standard Hollow Screw Nobel Biocare Replace Select Tapered Bra˚nemark MKIII NobelActive Osstem Wide diameter Straumann Standard Nobel Biocare Replace Select Tapered NobelActive Miscellaneous Linkow blade vent BOI implantb Unknown Total Q14

Anatomical region

Time span in function

10 mm

<3 months

5 1

3–12 months

1 1

9 2 2 1

2 3 3 1

4 2 1

Posterior

1 1

4 3

7 78

3 8

10 16 4

1 2

3 1

3 2

2 2

2 18

2 4 6 69

2 5 35

1 1 4 2

4 6 2 1 4

Posterior

2 4 4 17

9 2

12 17 6 1

Maxilla

>12 months

2 3

2 3 1

Mandible

9 10 5

2 2 6 48

Narrow diameter 3.0–3.5 mm; regular diameter 3.75–4.3 mm; wide diameter 4.8 mm. b Basal osseointegrated implant.

a Q13 Table 2. Explantation techniques according to the implant type and the diameter.

Implant type and diameterb Narrow diameter Straumann Standard Bone level Nobel Biocare Replace Select Tapered NobelActive Regular diameter Straumann Standard Hollow Screw Nobel Biocare Replace Select Tapered Bra˚nemark MKIII NobelActive Osstem Wide diameter Straumann Standard Nobel Biocare Replace Select Tapered NobelActive Miscellaneous Linkow blade vent BOI implantd Unknown Total

BF/hBEF

HTW

Total

2 (2)c 1

5 1

1 1

1 2

2 3

5 1 8 4 1 1

4 1 11 (2)

9 2 6 5 (1) 6 1 (1)

14 20 7 2

3 1

3 2 (1)

6 3 2 4

5 38

3 19

3 32

2 4 11 95

BF: bur–forceps technique; hBEF: neo bur–elevator–forceps technique; TD: trephine drill technique; HTW: high torque wrench technique; Q14 SF: scalpel–forceps technique. b Narrow diameter 3.0–3.5 mm; regular diameter 3.75–4.3 mm; wide diameter 4.8 mm. c The figure in brackets denotes the number of unsuccessful attempts. d Basal osseointegrated implant.

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Removal of dental implants Table 3. Success rate of explantation techniques used for the removal of implants. Explantation techniquea

Successful removal Yes No Total

BF/hBEF

HTW

Total

38 0 38

17 2 19

27 5 32

6 0 6

88 7 95

BF: bur–forceps technique; hBEF: neo bur–elevator–forceps technique; TD: trephine drill technique; HTW: high torque wrench technique; SF: scalpel–forceps technique.

Table 4. Explantation techniques used for the removal of implants according to the time scale of use. Explantation techniquea

Time scale of implant removal 2003–2010 2010–2013 Total

BF/hBEF

HTW

Total

29 9 38

19 0 19

0 32 32

2 4 6

50 45 95

BF: bur–forceps technique; hBEF: neo bur–elevator–forceps technique; TD: trephine drill technique; HTW: high torque wrench technique; SF: scalpel–forceps technique.

into the polished neck of the implant damaging it without being able to unwind it, as occurred in two cases in the present study (Table 2). In these two cases, hBEF was used successfully following failed HTW. The TD technique, despite its simplicity in use, has been shown to be unpredictable when utilized without a guiding cylinder/ pin, since it may be difficult to follow the implant axis; either a considerable distortion of the drill and the implant has occurred or an unwanted quantity of bone removed. We have abandoned the use of TD in narrow alveolar ridges where narrow platform implants are usually inserted

and in cases where the cortical thickness around implants has been less than 1.5 mm, irrespective of the alveolar bone width. In such instances either a very thin cortical plate remains or a through-andthrough bony defect can be created. Furthermore TD is not indicated in cases where there is no gap between the failing implant and the neighbouring tooth/implant, since they can be damaged during the procedure. The BF technique has been used for many years in implant dentistry, long before HTW and TD were introduced into clinical practice. In this study it was reserved for the removal of failing implants

Fig. 6. Explantation protocol for a failing implant in relation to the proximity of the neighbouring tooth/implant. BF: bur–forceps technique; hBEF: neo bur–elevator–forceps technique; TD: trephine drill technique; HTW: high torque wrench technique.

without a gap to the neighbouring tooth/ implant and in cases of HTW failure. It has been shown to be a time-consuming and occasionally tedious procedure, especially when drilling out implants of considerable length (14–16 mm). When thick cortical bone has to be removed over the implant length, a bur can slip and dig into the implant surface, thus the wound becomes contaminated by metal dust or particles. During the removal of fully osseointegrated implants in the mandible, substantial damage to the implant surface can occasionally be expected as a result of laborious attempts to remove the cortical bone around it. This metal contamination may interfere with GBR procedures in cases where this is planned as an immediate treatment. It has proved feasible to insert a new implant into the explantation site, however with complex manoeuvres that require soft tissue management, GBR, and lateral augmentation. We are of the opinion that it would be more predictable to perform GBR alone and postpone implant placement following the use of the BF technique. The hBEF technique has been developed as a novel approach resulting from the increased interest of patients with failing implants to receive a new implant immediately after the failing one has been removed. The trigger was the difficulty unwinding a failing implant despite the fact that only small portion of it was osseointegrated. It was observed by chance that it is feasible to dislodge failing implants by pushing them either with an elevator or with dental forceps. This technique has demonstrated its predictability, especially in preserving facial and lingual cortices, thus enabling the insertion of a new implant, occasionally of the same length and diameter. It is certainly more predictable to use a slightly larger diameter when feasible. In such cases, the availability of different implants systems, diameters, and lengths can be of great assistance. Thus, the diameters of failing implants removed using this technique of 3.3 mm, 3.5 mm, 3.75 mm, 4.0 mm, and 4.1 mm have been replaced successfully with implants of 3.5 mm, 3.75 mm,

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4.0 mm, 4.1 mm, and 4.3 mm diameters, respectively; this can be achieved using Straumann and Nobel implants, as was the case in the present study. It can be speculated that the preservation of the facial/ lingual cortex, as well as minimal bone Q9 loss mesial and distal to the implant and the creation of an ovoid crestal defect that can easily be grafted (Fig. 2F), are responsible for the predictability of this technique. With the introduction of the HTW technique it has been used less frequently and is reserved for cases of HTW failure or for the removal of fractured implants. All five explantation techniques reviewed, namely BF, hBEF, TD, HTW, and SF, appeared to be successful in removing failing implants. The BF/hBEF and SF techniques demonstrated 100% success. The hBEF technique enabled safe insertion of a new implant at the same explantation site. SF is reserved for bladetype implants. The HTW technique appears to be the most elegant, with the highest predictability of insertion of another implant during the same sitting without the need for additional procedures. Q10 The TD technique is a straightforward technique when used with a guiding pin; the indication for this technique is limited to cases with thin crestal cortical bone, as well as cases where there is no gap between the failing implant and the adjacent tooth/implant. An explantation protocol is proposed. The selection of the explantation technique, as far as screw-type implants is concerned, depends on two factors: the proximity of the failing implant to the neighbouring tooth/implant and the cortical thickness around it. Taking these into consideration and based on the simplicity of the procedure as well as the possibility of insertion of a new implant in the explantation site, the explantation protocol shown in Fig. 6 is proposed. Funding

None.

Competing interests

None.

11.

Ethical approval 12.

Ethical approval was obtained (Eticki komitet Drustva privatnih doktora stomatologije Srbije, No. 1/2015). Patient consent

13.

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Address: Zoran Stajcˇic´ Dental/Medical Clinic of Maxillofacial Surgery ‘‘Beograd-Centar’’ Kraljice Natalije 35 Belgrade 11 000 Serbia. Fax: +381 11 3610 764 E-mail: beogradcentar@icloud.com