Clinical Paper

Dental Implants

Int. J. Oral Maxillofac. Surg. 2016; 45: 641–648http://dx.doi.org/10.1016/j.ijom.2015.11.003, available online at http://www.sciencedirect.com

Removal of dental implants:review of five differenttechniquesZ. Stajcic, L.J. Stojcev Stajcic, M. Kalanovic, A. Ðinic, N. Divekar, M. Rodic:Removal of dental implants: review of five different techniques. Int. J. OralMaxillofac. Surg. 2016; 45: 641–648. # 2015 International Association of Oral andMaxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Abstract. The aims of this study were to review five different explantation techniquesfor the removal of failing implants and to propose a practical clinical protocol.During a 10-year period, 95 implants were explanted from 81 patients. Explantationtechniques 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. Themost frequent indications for implant removal were peri-implantitis (n = 37) andcrestal bone loss (n = 48). The posterior maxilla was the most frequent site ofimplant 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. Explantationtechniques appeared to be successful for the removal of failing implants. The BF/hBEF and SF techniques demonstrated 100% success. The hBEF technique enabledsafe insertion of a new implant in the same explantation site. The HTW techniqueappeared to be the most elegant technique with the highest predictability forinsertion of another implant. An explantation protocol is proposed.

0901-5027/050641 + 08 # 2015 International Association of Oral and Maxillofacial Surge

Z. Stajcic1, L. J. Stojcev Stajcic2,M. Kalanovic2, A. Ðinic2, N. Divekar1,M. Rodic1

1Dental/Medical Clinic of MaxillofacialSurgery ‘‘Beograd-Centar’’, Belgrade, Serbia;2Clinic of Oral Surgery, School of Dentistry,University of Belgrade, Belgrade, Serbia

Key words: dental implant explantation; dentalimplant failure; peri-implantitis; dental implantcomplications.

Accepted for publication 3 November 2015Available online 10 December 2015

The current literature provides ample data onthe high success rates of dental implanttreatment, which range from 90% to 97%.Failing implants are usually removed eitherbecause of progressive bone loss due to aperi-implant infection,1,2 frequently associ-ated with occlusal overload,3 or due toplacement in aesthetically unacceptablelocations.4 Explantation is also performedon osseointegrated orthodontic implants fol-lowing the termination of the orthodontic

treatment.5 Furthermore, implants associat-ed with a good bony and soft tissue conditionare occasionally removed in psychologicallyunstable patients.6

Different techniques for dental implantremoval have been proposed in the litera-ture, such as the use of thin burs or atrephine drill at low speed under watercooling,6–8 the use of an electro-surgeryunit to cause thermo-necrosis of thebone and subsequent weakening of the

bone–implant interface,9,10 and laser-assisted explantation,11 as well as a removaltorque procedure.12,13

Available data on explantation techni-ques appear to be inconsistent, thereforethere is no reported unique treatment pro-tocol for the successful and least traumaticremoval of dental implants. The employ-ment of less traumatic manoeuvres seemsto be required to create minimal residualbony defects and spare the soft tissues.

ons. Published by Elsevier Ltd. All rights reserved.

642 Stajcic et al.

Fig. 1. Failing implants in the posterior max-illa removed using the bur–forceps (BF) tech-nique. (A) Preoperative condition with thebone loss affecting the buccal aspect of theimplants. (B) Three-sided bone defects fol-lowing explantation.

Ideally, the explantation procedure shouldbe followed either by the installation ofanother implant or by guided bone regen-eration (GBR), or both at the same sitting,when indicated.

The aim of this study was to review fivedifferent explantation techniques based onthe authors’ clinical material, in order todescribe their advantages and disadvan-tages and to offer a practical clinical pro-tocol for the explantation of failingimplants.

Materials and methods

In this retrospective cohort study, the den-tal records of 112 patients of both sexeswho had been subjected to the removal ofa total of 129 dental implants over a 10-year period (2003–2013) were examined.Seventy patients were referrals. The dentalrecords of 31 patients from whom 34implants were removed were excludedfrom the study on the basis of the follow-ing criteria: accidental removal of theimplant (1) at the time of the cover screwbeing replaced by the healing abutment(n = 6); (2) with the tightening force of35 N cm applied for mounting the abut-ment (n = 13); (3) as a result of failingosseointegration without symptoms orsigns of peri-implantitis at routine fol-low-up (n = 8); (4) becoming loose inthe infected bone (n = 3). All other failingimplants, irrespective of the cause, wereremoved using dental forceps and rota-tional and/or rocking movements only(n = 4).

The dental records of the remaining 81patients with a total of 95 implants re-moved were analyzed with respect to theeffectiveness of the surgical techniquesapplied, indications for explantation, theanatomical distribution of the implantsremoved, and the implant types, dia-meters, and lengths.

Surgical techniques applied in the pres-ent study are described as the bur–forcepstechnique (BF), the neo bur–elevator–for-ceps technique (hBEF), the trephine drilltechnique (TD), the high torque wrenchtechnique (HTW), and the scalpel–forcepstechnique (SF). Apart from the SF tech-nique, all techniques were used only forimplants indicated for removal with a min-imum of 1/3 of the threads and that werewell osseointegrated without any mobility.

The bur–forceps technique (BF)

After elevation of a mucoperiosteal flap, asmall sized round and/or fissure bur (Nos.3–4) is used to remove the bone, usuallyfrom the facial aspect down to the apex of

the implant, taking care to preserve thelingual cortex and as much of the bone aspossible mesially and distally (Fig. 1). Ifbone resorption is found on the lingualside (this occurred in two cases), with thefacial cortex intact, then the bony defect isdeepened on the lingual side sparing thefacial cortex. The implant is then graspedwith the dental forceps and an attemptmade to remove it by rotational and slightrocking movements, similar to tooth ex-traction. If this is not feasible, more boneis drilled out until it is possible to eitherunwind it or luxate it towards the bone-removed region, thus creating a three-wallbony defect.

The neo bur–elevator–forceps technique

(hBEF)

This technique commences with the re-moval of bone mesially and distally fromthe implant, aiming towards the apex.Round and/or fissure burs (No. 1) are used,with copious running saline, trying tomaintain a close distance to the implantsurfaces (Fig. 2A). The implant head isgrasped with the corresponding tooth/Lyerforceps and turned clockwise and anti-clockwise. When resistant to suchattempted movements, a thin straight ele-vator (Couplands elevator No. 3) is placed

into the mesial and distal crevices, inter-mittently applying small gentle rotatingmovements similar to those used for theextraction of buried roots, until the im-plant is noted to be slightly tilted to oneside (Fig. 2B). Then, the elevator is placedinto the crevice on the contralateral sideand similar movements performed. Theimplant head is then grasped with dentalextraction forceps and gentle rockingmovements applied, pushing it mesiallyand distally only, thus preserving both thefacial and the lingual cortical plates(Fig. 2B). When little resistance is felt,the implant is removed with a final anti-clockwise rotation leaving an ovoid defect(Fig. 2C).

The trephine drill technique (TD)

An appropriate trephine drill with a diam-eter and length corresponding to the sizeof the implant to be removed is selected(Fig. 3A). The healing abutment or abut-ment/crown is unscrewed and a mucoper-iosteal flap raised if necessary. Thetrephine drill is sunk over the implant intothe bone using low speed 50–80 rpm dril-ling and light pressure with running salinecooling. A hole is drilled taking care thatthe trephine has been sunk to the exactdepth by controlling the outside rings onthe drill. For implant systems that do notprovide a guiding cylinder/pin, a healingabutment of smallest emergence profilediameter is mounted before using the tre-phine. For Straumann Standard and Stan-dard Plus implants, the polished neck isreduced with a high-speed diamond drill tocorrespond to the diameter of the guidedcylinder (Fig. 3B). In the event that theimplant is still firm after the trephine hasbeen lifted (in cases of insufficient drillingdepth), a Couplands elevator is placed intothe empty space and lightly twisted tobreak the bony connections, enabling easyremoval of the implant using the finger-tips.

The high torque wrench technique (HTW)

For the patients included in this study, theNeo Fixture Remover Kit (NeobiotechCo., Korea) was used for this technique.The compatibility list was consulted firstto determine the correct dimension of thefixture remover screw and the implantremover to fit to the implant chamberand outer diameter, respectively.

The procedure commences with the re-moval of the cover screw or the abutmentof the implant to be removed. The fixtureremover screw is inserted clockwise(Fig. 4A) and tightened using the torque

Removal of dental implants 643

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

Fig. 3. The trephine drill (TD) technique. (A)The trephine drill is selected to match thediameter of the failing implant. (B) Beforeusing the trephine drill for the removal of aStraumann Standard or Standard Plus implant,the polished neck is trimmed with a diamondbur to the size of the implant body diameter.

wrench with a torque of 50 N cm(Fig. 4B). The fixture remover screw,which features a specific thread designat the apical tip, is attached to the receiv-ing implant chamber, while the oppositeend has a fixed constant diameter. Thenext instrument, named the implant re-mover, is manually screwed onto the freeend of the fixture remover screw in an anti-clockwise direction (Fig. 4C). Once theimplant remover has been seated, the dy-namometric ratchet is set in an anti-clock-wise direction and force applied to unwindthe implant (Fig. 4D). It usually takes afew seconds until less resistance is felt.During this time, the implant and thesurrounding bone are cooled using saline,since an increase in bone temperature isexpected as a result of high friction (300–500 N cm). After one to two turns with thetorque wrench, almost no resistance isusually felt and the implant is manuallyunscrewed (Fig. 4E). If the implant doesnot become loose despite maximal torqueapplied, the implant remover is temporar-ily removed, and a No. 1 round bur used toremove the bone around the implant neckdown to the second or third thread; theimplant remover is then mounted again,applying sufficient torque until the implantbecomes loose. Following the terminationof the procedure, when successful, the

644 Stajcic et al.

Fig. 4. The high torque wrench (HTW) technique. (A) The fixture remover screw is mounted onto the failing implant manually. (B) The fixturescrew is tightened with the high torque wrench, with a torque of 50 N cm, clockwise. (C) The implant remover is manually screwed onto the freeend 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) After1–2 turns with the torque wrench, the implant is manually unscrewed.

implant is removed together with the fix-ture remover screw and the implant re-mover. The implant remover and thefixture remover screw are dismantled fromthe removed implant by simultaneous useof the torque wrench and the pliers, firstlyturning the implant remover clockwiseand secondly the fixture remover screwanti-clockwise.

Re-use of the fixture remover screw andimplant remover is possible with caution.The fixture remover screw may be re-usedonce or twice provided that a low unwind-ing force has been applied. The implantremover, however, may be re-used morefrequently, until the tips become blunt.

The scalpel–forceps technique (SF)

This technique was used only for implantswith an old-fashioned blade design, aswell as ‘basal osseointegrated implants’(BOI),14 which are supposed to be an-chored to the bone by a combination ofosseointegration and connective fibroustissue bands, formerly defined as ‘fibro-osseointegration’.15

The Linkow-type blade vent implanthead is grasped with dental forceps anda luxation movement started with constantpulling.16 The scalpel is used to sever theconnective tissue bands all around theimplant. This may take some time, anddespite wobbling and mobility, it is notpossible to extract the implant until the last

connective tissue band is released(Fig. 5A–C). For BOI, in the event thatthe horizontal part is bent, this must firstbe straightened with Lyer forceps and theimplant head grasped with dental forcepswith one hand. The scalpel in the otherhand is used to sever the connective tissuewhile the implant is pulled constantlytowards the lateral aspect of the jaw untilthe least resistance is felt.

Results

A total of 95 implants were removed. Ofthese 95 implants, 53 were removed fromthe maxilla and 42 from the mandible. Theindications for explantation were recurrentperi-implantitis not responding to treat-ment in 37 cases, crestal bone loss in 48cases, neurosensory deficit of the inferioralveolar nerve as a result of compressionin two cases, chronic periodontitis of theneighbouring teeth affecting the implantin five cases, implant fracture in two cases,and osteomyelitis in one case. The ana-tomical distribution of the implants re-moved and the implant types, diameters,and lengths are described in Table 1. Theposterior maxilla was the most frequentsite of implant removal (n = 48), followedby the posterior mandible (n = 35). Themajority of implants (n = 69) wereremoved after a minimum of 1 year infunction. The longer implants were morefrequently removed (n = 78) when

compared to implants with a length of lessthan 8 mm (n = 17).

It was possible to insert another implantat the same sitting in 23 explantation sites.Of these, 17 were inserted following theuse of the HTW technique, five followingthe hBEF technique, and one followingthe TD technique. Of the 23 insertedimplants, two failed osseointegration (af-ter 4 and 6 months respectively); newimplants were inserted and are still infunction 2 years after placement. Theremaining 72 explantation sites that wereleft open healed uneventfully.

Explantation techniques according tothe implant type and diameter are shownin Table 2. With regard to the efficacy ofthe techniques applied, the BF/hBEF tech-niques proved to be the most efficient(Table 3). The TD technique failed intwo out of 19 attempts, whereas theHTW technique failed in five out of 32cases. The hBEF technique proved suc-cessful even when TD and HTW failed(seven cases). The time scale of the use ofthe implant removal techniques is summa-rized in Table 4.

Discussion

The number of implants placed has in-creased dramatically over the last decade,thus the number of failures is expected togrow accordingly. This necessitates theinvolvement of the implant industry in

Removal of dental implants 645

Fig. 5. The scalpel–forceps (SF) technique.(A) Preoperative radiographic image of afailing Linkow-type blade implant in the up-per jaw. (B) The implant-supported crown isgrasped with the dental forceps after the fi-brous bands around the implants have beensevered with a scalpel. (C) The removedimplant with the soft tissue capsule around it.

providing the required equipment, as wellas implant surgeons to develop new sur-gical techniques that can be used not onlyto remove a failing implant with very littledamage, but also to insert another one atthe same implant site when indicated.Changes in the implant industry haveled us to modify our surgical techniquedramatically (Table 4). Until 2010, BF/hBEF and TD were used almost exclu-sively for the removal of failing implants,whereas within the last 3 years, the HTWtechnique has become the first choicetreatment (71%) because of its simplicityand elegance, as well as predictable inser-tion of another implant at the same osteot-omy site.

It has been reported that the followingoccurrences can contribute to an increase

in the implant failure rate: a low insertiontorque of implants that are planned to beloaded immediately or early, an inexperi-enced surgeon inserting the implants, im-plant insertion in the maxilla, implantinsertion in the posterior regions of thejaws, implants in heavy smokers, implantinsertion in bone quality of types III andIV, implant insertion in places with smallbone volumes, the use of shorter lengthimplants, a greater number of implantsplaced per patient, lack of initial implantstability, use of cylindrical (non-threaded)implants and prosthetic rehabilitation withimplant-supported overdentures, the useof the non-submerged technique, immedi-ate loading, and implant insertion in freshextraction sockets, as well as the use ofsmaller diameter implants.17 However,crestal bone loss and peri-implantitis werethe most frequent causes of implant re-moval in the present study, although thesample was too small for definite conclu-sions to be drawn.

This study showed that explantationtechniques are generally efficient, with alow failure rate; BF/hBEF proved to be100% successful and can be recommendedas a safe and reliable technique shouldothers fail. The SF technique was appliedfor old-fashioned blade vent implants,which have not been in use in the lastthree decades, as well as for BOI, whichhave been employed sporadically; thus itis expected that this technique will be usedrarely and is not a matter of further dis-cussion.

Irrespective of the efficacy of explan-tation techniques, two patients with neu-rosensory deficit of the inferior alveolarnerve did not improve following success-ful removal of the implants causing symp-toms.

When the BF, hBEF, TD, and HTWtechniques are compared on the basis oftechnical requirements, the time requiredfor their execution, and on patient andsurgeon compliance, it should be empha-sized that the BF and hBEF techniquesproved to be the most reliable, versatile,and predictable; however, they are notwell accepted by patients because of thedrilling noise, force applied, and thelength of time needed. The HTW andTD techniques have been shown to bequick, elegant, and well accepted by bothpatients and surgeons; however they havelimitations that need further elaboration.

With regard to the HTW technique,specially designed instruments or kitsare needed, which vary from companyto company (the Straumann 48 h explan-tation device (Straumann), the Neo Fix-ture Remover Kit (Neobiotech), BTI

Implant Extraction System (Biotechnolo-gy Institute S.L.), Implant Retrieval Tool(Nobel Biocare)). In essence, two types ofinstrument are used, one of a screw-type toengage the implant and the other a high-torque dynamometric ratchet to unwindthe implant. These kits have recently beenbrought to the dental market and thereforedata on their use in the literature arescarce.12 The use of removal torque forexplantation of orthodontic mini-implantshas already been documented in the liter-ature.13,18,19 Since orthodontic mini-implants have a diameter not larger than2 mm and length of 7–17 mm, the reportedremoval torque values have been smallerthan those required for unscrewing dentalimplants of a standard diameter andlength.13,18 A more recent retrospectivelongitudinal study described the Biotech-nology Institute extraction kit for explan-tation, which consists of a wrench thatallows a 200 N cm counter-torque force,an internal connection extractor, an ex-tractor for external connection, and a set ofratchet handle extension pieces. This tech-nique appears to be the least traumatic andbiologically acceptable, since after it hasbeen used there is almost no bony defectleft except an empty implant bed prepara-tion site.12 These findings correlate withthe results found in the present study.

However, HTW has its limitations.Open systems such as the NeobiotechFixture Remover Kit, which was usedfor 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 tobe used to determine the correspondingdiameter of the fixture remover screw.Fracture of the fixture remover screw islikely should high torque be applied. In thecase of vertical implant fracture duringinstallation when excessive torque is ap-plied (as has happened in our patientsusing narrow platform NobelReplace orNobelActive implants), this explantationtechnique has not been feasible. Withregard to osseointegrated Straumann Stan-dard or Straumann Standard Plus implantsin the mandible, the implant remover maydig into the polished neck of the implantdamaging it without being able to unwindit, as occurred in two cases in the presentstudy (Table 2). In these two cases, hBEFwas used successfully following failedHTW.

The TD technique, despite its simplicityin use, has been shown to be unpredictablewhen utilized without a guiding cylinder/pin, since it may be difficult to followthe implant axis; either a considerabledistortion of the drill and the implant

646 Stajcic et al.

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

Implant type and diametera Implant Anatomical region

Length Time span in function Mandible Maxilla

�8 mm �10 mm <3 months 3–12 months >12 months Anterior Posterior Anterior Posterior

Narrow diameterStraumann

Standard 5 5 1 2 2Bone level 1 1 1

Nobel BiocareReplace Select Tapered 2 1 1 1 1NobelActive 3 1 1 1 1 1 1

Regular diameterStraumann

Standard 9 9 5 4Hollow Screw 2 2 2

Nobel BiocareReplace Select Tapered 2 12 2 2 10 1 4 9Branemark MKIII 3 17 1 3 16 2 6 2 10NobelActive 1 6 3 4 2 5

Osstem 1 1 1Wide diameter

StraumannStandard 4 4 4

Nobel BiocareReplace Select Tapered 2 4 3 3 2 4NobelActive 1 3 1 1 2 2 2

MiscellaneousLinkow blade vent 2 2 2BOI implantb 4 4 2 2Unknown 4 7 3 2 6 5 6

Total 17 78 8 18 69 7 35 5 48a Narrow diameter 3.0–3.5 mm; regular diameter 3.75–4.3 mm; wide diameter �4.8 mm.b Basal osseointegrated implant.

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

Implant type and diameterb BF/hBEF TD HTW SF Total

Narrow diameterStraumann

Standard 3 2 (2)c 5Bone level 1 1

Nobel BiocareReplace Select Tapered 1 1 2NobelActive 1 2 3

Regular diameterStraumann

Standard 5 4 9Hollow Screw 1 1 2

Nobel BiocareReplace Select Tapered 8 6 14Branemark MKIII 4 11 (2) 5 (1) 20NobelActive 1 6 7

Osstem 1 (1) 1Wide diameter

StraumannStandard 4 4

Nobel BiocareReplace Select Tapered 3 3 6NobelActive 1 3 (1) 4

MiscellaneousLinkow blade vent 2 2BOI implantd 4 4Unknown 5 3 3 11

Total 38 19 32 6 95a BF: bur–forceps technique; hBEF: neo bur–elevator–forceps technique; TD: trephine drill technique; HTW: high torque wrench technique;

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.

Removal of dental implants 647

Table 3. Success rate of explantation techniques used for the removal of implants.

Successful removalExplantation techniquea

BF/hBEF TD HTW SF Total

Yes 38 17 27 6 88No 0 2 5 0 7Total 38 19 32 6 95

a 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 ofuse.

Time scale of implant removalExplantation techniquea

BF/hBEF TD HTW SF Total

2003–2010 29 19 0 2 502010–2013 9 0 32 4 45Total 38 19 32 6 95

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

has occurred or an unwanted quantity ofbone removed. We have abandoned theuse of TD in narrow alveolar ridges wherenarrow platform implants are usuallyinserted and in cases where the corticalthickness around implants has been lessthan 1.5 mm, irrespective of the alveolarbone width. In such instances either a verythin cortical plate remains or a through-and-through bony defect can be created.Furthermore TD is not indicated in caseswhere there is no gap between the failingimplant and the neighbouring tooth/im-plant, since they can be damaged duringthe procedure.

Fig. 6. Explantation protocol for a failing imneighbouring tooth/implant. BF: bur–forceps

technique; TD: trephine drill technique; HTW:

The BF technique has been used formany years in implant dentistry, long be-fore HTW and TD were introduced intoclinical practice. In this study it was re-served for the removal of failing implantswithout a gap to the neighbouring tooth/implant and in cases of HTW failure. It hasbeen shown to be a time-consuming andoccasionally tedious procedure, especiallywhen drilling out implants of considerablelength (14–16 mm). When thick corticalbone has to be removed over the implantlength, a bur can slip and dig into theimplant surface, thus the wound becomescontaminated by metal dust or particles.

plant in relation to the proximity of thetechnique; hBEF: neo bur–elevator–forcepshigh torque wrench technique.

During the removal of fully osseointe-grated implants in the mandible, substan-tial damage to the implant surface canoccasionally be expected as a result oflaborious attempts to remove the corticalbone around it. This metal contaminationmay interfere with GBR procedures incases where this is planned as an immedi-ate treatment. It has proved feasible toinsert a new implant into the explantationsite, however with complex manoeuvresthat require soft tissue management, GBR,and lateral augmentation. We are of theopinion that it would be more predictableto perform GBR alone and postpone im-plant placement following the use of theBF technique.

The hBEF technique has been devel-oped as a novel approach resulting fromthe increased interest of patients with fail-ing implants to receive a new implantimmediately after the failing one has beenremoved. The trigger was the difficultyunwinding a failing implant despite thefact that only small portion of it wasosseointegrated. It was observed bychance that it is feasible to dislodge failingimplants by pushing them either with anelevator or with dental forceps. This tech-nique has demonstrated its predictability,especially in preserving facial and lingualcortices, thus enabling the insertion of anew implant, occasionally of the samelength and diameter. It is certainly morepredictable to use a slightly larger diame-ter when feasible. In such cases, the avail-ability of different implants systems,diameters, and lengths can be of greatassistance. Thus, the diameters of failingimplants removed using this technique of3.3 mm, 3.5 mm, 3.75 mm, 4.0 mm, and4.1 mm have been replaced successfullywith implants of 3.5 mm, 3.75 mm,4.0 mm, 4.1 mm, and 4.3 mm diameters,respectively; this can be achieved usingStraumann and Nobel implants, as was thecase in the present study. It can be specu-lated that the preservation of the facial/lingual cortex, as well as minimal boneloss mesial and distal to the implantand the creation of an ovoid crestal defectthat can easily be grafted (Fig. 2C), areresponsible for the predictability of this

648 Stajcic et al.

technique. With the introduction of theHTW technique it has been used lessfrequently and is reserved for cases ofHTW failure or for the removal of frac-tured implants.

All five explantation techniquesreviewed, namely BF, hBEF, TD, HTW,and SF, appeared to be successful in re-moving failing implants. The BF/hBEFand SF techniques demonstrated 100%success. The hBEF technique enabled safeinsertion of a new implant at the sameexplantation site. SF is reserved for blade-type implants. The HTW techniqueappears to be the most elegant, with thehighest predictability of insertion of an-other implant during the same sitting with-out the need for additional procedures.The TD technique is a straightforwardtechnique when used with a guiding pin;the indication for this technique is limitedto cases with thin crestal cortical bone, aswell as cases where there is no gap be-tween the failing implant and the adjacenttooth/implant.

An explantation protocol is proposed.The selection of the explantation tech-nique, as far as screw-type implants isconcerned, depends on two factors: theproximity of the failing implant to theneighbouring tooth/implant and the corti-cal thickness around it. Taking these intoconsideration and based on the simplicityof the procedure as well as the possibilityof insertion of a new implant in the ex-plantation site, the explantation protocolshown in Fig. 6 is proposed.

Funding

None.

Competing interests

None.

Ethical approval

Ethical approval was obtained (Etickikomitet Drustva privatnih doktora stoma-tologije Srbije, No. 1/2015).

Patient consent

Not required.

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