mdb,c,

: Prof. DrcDoctoral Program in Morphological Sciences, Faculty odDepartment of Mathematics and Statistics, Universida

a r t i c l e i n f o

Article history:Paper received 5 January 2013Accepted 10 May 2013

IAN lesions.sevier Ltd. All rights

reserved.

postoperative period. Conventional surgical extraction of impactedmandibular third molars (M3M) requires lateral bone removal(Thoma, 1969) to allow an outwardly directed mobilization of thetooth. In cases of deep impaction this technique may be associated

a et al., 2005). Af the M3M and ofsed. Research hasemoval or extrac-Henrikson, 1974;

rrently being dis-cussed with the aim of reducing intra- as well as postoperativecomplications to a minimum (Praveen et al., 2007). Recently a shiftin paradigms can be observed towards atraumatic techniques inthird molar surgery, such as odontosection (Gen and Vasconcelos,2008; Arakeri and Arali, 2010; Ngeow, 2009) partial removal ofM3M crowns (Landi et al., 2010) and use of piezoelectric devices(Rullo et al. 2013). Flapless third molar surgery has been shown inhorizontally dislocated teeth (Kim et al. 2011) which were partiallyerupted.

* Corresponding author. Department of Maxillofacial Surgery, University of Gt-tingen, Robert-Koch-Str. 40, 37099 Gttingen, Germany.

Contents lists available at

Journal of Cranio-Ma

e:

Journal of Cranio-Maxillo-Facial Surgery 42 (2014) 213e219E-mail address: wengelke@med.uni-goettingen.de (W. Engelke). 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by El

1. Introduction

Third molars are present in 90% of the population, with 33%having at least one impacted third molar (Scherstn et al., 1989)thus extraction is a relatively common procedure. Extraction in-volves themanipulation of both soft and hard tissues, so the patientusually experiences pain, oedema, and trismus in the immediate

with the risk of mandibular angle fracture (Iidmucoperiosteal ap exposing the buccal bone othe adjacent second molar is most commonly ushown that such exposure, even without bone rtion, leads to bone resorption (Bergstrm andWood et al., 1972; Yaffe et al., 1994, 1997).

Morbidity following third molar surgery is cuadjacent to mandibular third molars and may reduce postoperative morbidity without raising the risk ofKeywords:Mandibular third molarsEndoscopesMicrosurgical removalOcclusal approach1010-5182/$ e see front matter 2013 European Asshttp://dx.doi.org/10.1016/j.jcms.2013.05.003. Ramn Fuentes), Faculty of Dentistry, Universidad de La Frontera, Temuco, Chilef Medicine, Universidad de La Frontera, Temuco, Chiled de La Frontera, Temuco, Chile

a b s t r a c t

Purpose: Conventional surgical extraction of impacted mandibular third molars (M3M) requires a lateralap reection in conjunction with lateral bone removal for outward mobilization of the tooth. The aim ofthis report is to outline a novel inward fragmentation technique (IFT) in conjunction with an occlusalminiap approach to reduce the amount of bone removal to a minimum.Patients and methods: Seventeen consecutive patients (7 men and 10 women; mean age 24.4 years, range18e36 years) required the extraction of 21-impacted M3M with a close relationship to the inferioralveolar nerve (IAN).

Occlusal miniaps were used and only occlusal bone removal was performed to expose the M3Munder endoscopic vision. A central space-making cavity was created followed by inward fragmentationand mobilization of the crown and subsequent root removal through the space created.Results: 20 of 21 sites healed uneventfully, one late infection was observed, no permanent neurosensorylesion occurred. The mean preoperative buccal bone height was 15.5 (11e18) mm and the postoperativebuccal bone height 14.7 (11e17) mm. On the 2nd day, the mean swelling level was 1.38 (0e2) on a 4point scale, the pain level was 2.30 (0e5) on a 10 cm VAS, mean pain duration was 2.04 days.Conclusion: An inward fragmentation technique allows preservation of >90% of the buccal bone heightDepartment of Oral and Maxillofacial SurgeryGttingen, GermanybDepartment of Adult Integral Dentistry (Heada (Head: Prof. Dr. Dr. Henning Schliephake), School of Dentistry, Georg-August-University, School of Dentistry,Removal of impacted mandibular thirdfragmentation technique (IFT) e Metho

Wilfried Engelke a,*, Vctor Beltrn b, Mario CantnRamn Fuentes b

journal homepagociation for Cranio-Maxillo-Facialolars using an inwardand rst results

Eun-Jin Choi a, Pablo Navarro d,

SciVerse ScienceDirect

xillo-Facial Surgery

www.jcmfs.comSurgery. Published by Elsevier Ltd. All rights reserved.

inclusion in the study, in particular with regard to the time neededfor the surgery and the pros and cons of the conventional vs. inwardfragmentation technique.

2.1. Surgical procedure

Surgery was performed under local anaesthesia (4% Articainewith 1:100,000 epinephrine. The surgeon worked in a 12 oclockposition observing the site on a video screen via a Storz Hopkinssupport endoscope (30 view angle, 2.7 mm or 4mm diameter, KarlStorz, Tuttlingen, Germany) (Fig. 1). The support endoscope wasplaced posterior to the surgical site. Surgery is shown step by stepin Figs. 2e6.

A sulcus incision was performed near the mesiobuccal edge ofthe second molar to its distal surface. The incision line continuedsagittally towards the mandibular ramus along the extension of theM3M. Soft tissue reection was carried out over the crest only toallow the insertion of the support endoscope at the distal aspect ofthe site; no reection of the periosteum was performed on thelateral and lingual aspects of the M3M region (Fig. 2A).

Crestal exposure of the M3M was performed using a round burwith a low speed handpiece and sterile saline irrigation. Exposure

Fig. 1. Storz Hopkins support endoscope.

axillo-Facial Surgery 42 (2014) 213e219Despite this there is no signicant discussion in the literature onhow to perform atraumatic procedures in particular for complexsituations and fully impacted M3M in close relationship with theIAN.

In implant surgery, apless techniques have become increas-ingly important. There are signicant advantages, which makeapless surgery attractive for both surgeon and patient (Choi andEngelke, 2009): Minimal trauma to the soft tissue reduces scarformation, preservation of osseous vascularization via the perios-teum and reduced patient discomfort. As an alternative to punchtechniques, occlusal mini-incisions have been used in implantsurgery (Choi et al., 2010). For exodontic surgery in contrast,occlusal miniaps have not been recommended previously due toinadequate visualization of the surgical site.

Endoscopically assisted procedures are currently being intro-duced in maxillofacial traumatology (Mensink et al., 2009) andorthognathic surgery (Gonzles-Garca, 2012; Mommaerts, 2010;Rohner et al., 2001). In oral surgery endoscopes have contributed toreduction of the trauma of augmentation procedures, in particularsinus oor elevation (Engelke and Capobianco, 2005; Schleier et al.,2008). Iwai et al. (2012) used endoscopes to remove a displacedmaxillary third molar via the extraction socket. In a study todetermine the indications, efcacy, and advantages of the supportimmersion endoscopic method for extraction socket assessment,Juodzbalys et al. (2008) stated Support immersion endoscopy canbe used as an adjunct tool in assessing extraction socketmorphology and bone conditions without ap elevation.

Using support immersion endoscopy (Engelke, 2002) it hasbecome possible to reduce the osseous trauma in implant surgery.The use of rigid endoscopes has been also reported for visualizationof anatomical structures in the oral cavity in various indications(Beltrn et al., 2012). The improvement of visualization has createdthe basis for a change towards less invasive removal of M3M, whichformerly was impossible to achieve due to limited insight into theintraalveolar site (Engelke et al., 2011). The aim of the presentreport is to present a novel inward fragmentation technique via anocclusal miniap approach used to reduce the surgical traumacaused by the conventional bone removal access and outwardmobilization of the impacted M3M in complex anatomicalsituations.

2. Materials and methods

21 consecutive mandibular third molars (9 right, 12 left side)were included in a prospective study on 17 medically healthy pa-tients (10 women and 7 men) aged 18e36 years (mean age 24.4).The patients did not have any illness or take any medication thatcould inuence the surgical procedure or postoperative woundhealing. Only single side extractions were included. Patients hadbeen referred to the Department of Maxillofacial Surgery at Uni-versittsmedizin Gttingen, Germany and to the Centre of OralMicrosurgery at the Faculty of Dentistry of the Universidad de LaFrontera, Temuco-Chile. This study was approved by the researchethical committees of Gttingen University and Universidad de LaFrontera. Mandibular third molar removal was prompted by pro-phylactic and orthodontic considerations. The criteria for inclusionin the present study were M3M completely or partially impactedand completely covered by soft tissue with the absence of acuteinammatory symptoms. Only M3M with a close relationship(apical distance below 1 mm on cone-beam computed tomography(CBCT) or orthopantomogram (OPG), respectively) to the mandib-ular canal were included. Thus, all cases belonged to a high-riskgroup for postoperative neurosensory disturbances. All teethwere removed under local anaesthesia. Before the surgical proce-

W. Engelke et al. / Journal of Cranio-M214dure, all patients accepted and signed the informed consent forFig. 2. Schematic diagram of endoscopic odontosection, third molar removal by sup-port endoscopic assistance. Preoperative position of the molar and its close relation

with the inferior alveolar nerve. A, sulcular incision. B, Crestal exposure of the thirdmolar. SE e Support endoscopy.

axilW. Engelke et al. / Journal of Cranio-Mwas restricted to the occlusal aspect only, independently of theangulation and degree of impaction of the tooth (Fig. 2B).

Trepanation of the M3M was performed using Lindemannstraight burs in order to provide access to the pulp. The trepanationwas oriented in a transverse direction intending to create an in-ternal space-making cavity, which may vary depending on the in-dividual situation. The transverse cut was performed in the buccaland central parts of the crown with the exception of the lingualaspect (Fig. 3A). Thus, using a round bur with a low speed

Fig. 3. A, Trepanation oriented in a transverse direction using a Lindemann straightbur. SE e Support endoscopy, LB e Lindemann straight bur. B, Internal reduction of thecrown. RB e Round bur.

Fig. 4. A, Crown reduction under direct vision using large a diamond bur. SE e Supportendoscopy, DRB e Diamond round bur. B, Removal of the mesial part of the crown.E e Elevator.lo-Facial Surgery 42 (2014) 213e219 215handpiece and sterile saline irrigation, the pulp was opened widelytowards the level of the furcation in order to obtain a space forinward fragmentation of the crown. At the same time an overviewof the internal tooth anatomy and the furcation area was obtained(Fig. 3B).

Crown removal was performed by inward fragmentation. Theuse of large diamond round burs in the furcation area is essential toensure complete separation of the roots before inward

Fig. 5. A, Mobilization of the distal root with a round bur under direct vision.SE e Support endoscopy, SRB e Straight round bur. B. Distal root removed withelevator. E e Elevator.

Fig. 6. A, Final control of the alveolus under endoscopic vision for root remnants anddetermination of the bone level using a periodontal probe. SE e Support endoscopy,PP e Periodontal probe. B, Closure with 2 interrupted sutures for primary healing.

fragmentation while avoiding lingual nerve damage (Fig. 4A).Following removal of the distal crown by inward fracturing with anelevator, the mesial part is luxated, also inwardly, (Fig. 4B) andsubsequently removed. In the majority of cases the adjacent rootcan be removed together with the mesial crown fragment. Thespace created by removal of the crown fragments opens the sighttowards the furcation area and remaining roots.

After removal of the crown, the remaining roots were identied(Fig. 5). The majority of roots could be removed with elevators. Incase of ankylosis the roots were removed with round burs underdirect vision. In critical zones at the lingual aspect of the mandibleand adjacent to the alveolar nerve, diamond burs mounted on a lowspeed handpiece were used.

Final examination of the alveolus was performed under endo-scopic vision for root remnants and determination of the bone levelusing a periodontal probe. Probing was performed along the axis of

W. Engelke et al. / Journal of Cranio-Maxil216the tooth to the buccal side with reference to the most apicalextension of the alveolus (Fig. 6A). Wound closure was performeddepending on the preoperative situation. The socket was rinsedwith physiological saline, and the incision was closed (Fig. 6B) with2 interrupted sutures (silk 4-0).

All patients received paracetamol 500 mg 4 times daily, addi-tionally an antibiotic treatment (amoxicillin 750 mg 3 times daily)was administered for 4 days.

2.2. Evaluation

Primary outcome parameters were: Preoperative bone height(POBH) and Intraoperative bone height (IOBH) following extraction,duration of surgery, swelling and pain level at 2 days, pain durationand postoperative complications. The POBH was assessed frompanoramic images (Fig. 7). A tangent (CT) was drawn along theocclusal crown surface, and the longitudinal axis (LA) of the M3Mwas constructed with reference to the most apical root tip (A). Boneheight (BH) was assessed along the longitudinal axis as the distanceof the apical point (A) to the intersection with the upper alveolarbone contour (BC).

The IOBH (Fig. 6A) was evaluated following tooth removal with aperiodontal probe placed along the longitudinal axis. The distanceof the apical point (A) to the upper alveolar bone contour (BC) wasmeasured.

Clinical controls took place at 2 and 7 days after surgery. At 2days, the pain level was determined on a 10 cm visual analoguescale (VAS), and the degree of swelling was ranked on a scale from0 to 3 (0: No swelling; 1: Light swelling (just visible); 2: Moderate(local) swelling and 3: Severe (extended) swelling. At 7 days aftersurgery, the patients were asked how many days their pain had

Fig. 7. Evaluation of the buccal bone height (BH), as distance of the apical point (A) of

the alveolus and the buccal bone contour (BC) along the longitudinal axis (LA) of theinferior third molar.persisted. One year following surgery, the patients les wererevised for postoperative complications. To minimize the risk ofbias a surgeonwho had not operated on the patients conducted thepostoperative examinations.

3. Results

During surgery, no intraoperative complications, such asbleeding, root fragment displacement, visible IAN trauma, lesionsof hard and soft tissues, were observed. All surgical interventionswere performedwithout the need to raise lateral aps. Amaximumvertical bone loss of 2 mm was observed. The mean duration ofsurgery was 27.3 (14e44) min. In Fig. 8, a typical case is shownwhich required a CBCT pre- and postoperatively due to a complexroot anatomy. In the preoperative CBCT the root tip is located at thebasal compact bone with close contact to the IAN, the M3M ismesially angulated, the crown is in alignment with the occlusalbone level exhibiting a reduced diameter of the lingual wall.Following removal using IFT, the CBCT taken immediately aftersurgery showed the exclusively occlusal approach without reduc-tion of the lateral or lingual bone walls with maintenance of theentire alveolar and perialveolar bone architecture. No root or crownremnants were present; the duration of surgery was 21 min.

In case of direct exposure of the inferior alveolar nerve, theendoscope served as a tool to document the IAN integrity. In Fig. 9the exposed IAN is demonstrated via an occlusal endoscopic viewusing. The support endoscopewas placed at the distal margin of thesite allowing a direct magnied view of the exposed nerve withintact alveolar walls.

The bone level analysis is presented in Table 1. Comparison ofbone levels before and following removal revealed a signicantmean bone loss of 0.8 mm (p < 0.01). However 94.8% of the bonepreviously adjacent to M3M was preserved using IFT. The post-operative symptoms pertaining to pain and swelling are light tomoderate as summarized in Table 2.

With respect to the postoperative swelling at day 2 as the mainpostoperative symptom, there was a signicant correlation be-tween the second day pain score, the duration of surgery and thepatients age. No correlationwas found concerning bone height andduration of pain (Table 3).

20 of 21 surgical sites healed uneventfully; one late infectionwas seen and 2 temporary incomplete neurosensory distur-bances, which recovered within 6 and 10 weeks after surgery,respectively were seen. No permanent neurosensory disturbanceswere noted.

4. Discussion

Modern dentistry is based on conservative thinking (Patel et al.,2010); taking into consideration that the reason for lateral anddistal bone removal for M3M extraction is to allow an outwarddirected mobilization, a modern technique should provide atechnical solution which preservation of the mandibular archi-tecture without the removal of bone necessary for outwardmobilization. As a goal an acceptable amount of bone loss might bedened as that which does not exceed the area occupied fornormal eruption. This may be achieved relying on the followingprinciples:

1) Optimized magnied visualization of the surgical site at anytime of the procedure in order to avoid lateral ap elevationand laterodistal bone removal.

2) Systematic and precise space making procedure in order toprovide stepwise fragmentation and inwardmobilization of the

lo-Facial Surgery 42 (2014) 213e219tooth.

Fig. 8. Cone-beam computed tomographic cross-sectional slice of the third molar area. A, Iclearly visible. B, In postsurgical slices the third molar was completely removed by the end

Fig. 9. Intraoperative nerve exposure: visualization under support endoscopy (Arrowshows the exposure of inferior alveolar nerve).

W. Engelke et al. / Journal of Cranio-Maxillo-Facial Surgery 42 (2014) 213e219 217It is well known in constructional engineering that a controlleddemolition of buildings may be achieved by an implosion tech-nique, thus collateral damage of adjacent buildings in the imme-diate neighbourhood can be avoided. The implosion techniquemakes use of the fact, that the hollow construction of buildingsprovides sufcient void space to receive the collapsing structures.

n presurgical slices the close proximity of the roots and the inferior alveolar canal areoscopic occlusal approach, resulting in maintenance of the buccal wall.

Table 1Bone height measurement. T-test evaluation of POBH vs. IOBH revealed signicantdifference (p < 0.01).

n 21 POBH (mm) IOBH (mm)Mean 15.5 14.7Min. 11.5 12.0Max. 18 17.0Std. dev. 1.47 1.42

Table 2Postoperative symptoms in 17 patients.

n 21 Swelling level (0e3) Pain level (0e10) Pain duration (days)Mean 1.38 2.30 2.04Median 1 2 2Min. 0 0 0Max. 2 4 7

axilThe application of a similar principle for the removal of teeththerefore requires the formation of an internal cavity beforeapplying the implosion concept. This cannot be achieved byodontosection alone. Inward directed mobilization of a M3M onlycan be achieved, if the internal space is created sufciently large toreceive the crown fragments as well as the roots following sys-tematic odontosection under direct observation.

Minimally invasive apless removal of M3M (Kim et al., 2011)is limited to partially impacted and at least partially erupted cases.Depending on the angulation, position and anatomical factors ofthe M3M, apless removal implies odontosection and extractionwith elevators or forceps without bone removal. Unerupted M3Mwith various degrees of complex impaction exhibiting bone levelsabove the equator of the crown do not meet the criteria for aplessremoval. For these cases in particular, IFT offers a novel approachto conserve the adjacent bone and soft tissues. If the crown isimpacted below the occlusal bone level, the dimension of theocclusal bony access cavity lies within the range of the crowndiameter. The advantages for the patients are obvious: Reduction ofthe fracture risk, less traumatizing ap design and no detachmentofmasticatorymuscles. A high fracture risk is given in particular, if astable buccal wall during conventional removal is signicantlyreduced down to the basal bone level leaving only a delicate lingualstructure to guarantee mandibular stability (see Fig. 8). Asdemonstrated in the case example, the occlusal approach providesintact bone structures before and following removal to prevent anyrisk of intra- or postoperative instability of the mandible.

Support endoscopy (Beltrn et al., 2012) is a key technique toallow a direct observation of the internal anatomic structures ofalveolus. In this study, we used the technique in a standardizedmanner and without additional application of a microscope as in aprevious report (Engelke et al., 2011). This was due to the obser-vation that those complex cases, such as root fracture, with difcultaccess cannot be treated sufciently with microscopes only. Sup-port endoscopy as a magnifying optical tool provides adequate anddirect insight for this purpose (Beltrn et al., 2011; Cantn et al.,2012). This is in agreement with various reports on endodonticsurgery (von Arx et al., 2002; Taschieri et al., 2008a). Taschieri et al.(2008b) stated: The best possible intraoperative visualization isnecessary to maintain a high level of success. The support endo-scope provides an excellent overview of the internal aspects of theM3M from a distal perspective (Fuentes et al., 2012). Furthermore itallows the surgical eld to be viewed at various angles and dis-

Table 3Correlation of postoperative symptoms in 17 patients.

Symptom Associated variable p

Swelling level 2nd day Pain level 2nd day 0.013a

Swelling level 2nd day Bone height postoperative 0.14Swelling level 2nd day Duration of surgery 0.012a

Swelling level 2nd day Age 0.04a

Swelling level 2nd day Pain duration 0.668

a ANOVA, level of signicance p < 0.05.

W. Engelke et al. / Journal of Cranio-M218tances without losing depth of the eld and focus. Thus, a preciseodontosection and removal of tooth fragments is supported downto the level of the root tip without the need for lateral access. Inparticular the use of endoscopes seems to be very helpful whenremoving root fragments attached to the osseous walls of themandibular canal. As a means of safety, at the lingual aspect of thealveolus, as well as apically, in close relationship with themandibular canal we recommend the use of diamond round burs orpiezo-surgical instruments.

There is increasing evidence, that the use of endoscopes en-hances surgical procedures, in particular in orthodontic surgery(Gonzles-Garca, 2012; Mommaerts, 2010; Rohner et al., 2001). Itmay be speculated that the use of support sheathes as, demon-strated in our report, may also facilitate the observation of details ofthe ramus and the Le Fort 1 osteotomies and simultaneously mayserve as a tissue-separating tool. IFT technique furthermore may beapplied in some other alveolar bone sites (Hrzeler et al., 2010; Al-Harbi, 2010), providing a tool for atraumatic extraction in criticalanterior maxillary sites.

We observed an increase of postoperative symptoms dependenton the time of surgery. The mean duration of surgery in our reportmay be relatively long compared to previous studies (Renton et al.,2001; Bello et al., 2011; Chye et al., 1993), but can be explained bythe selection of complex cases. Additional time needed forsectioning and inward fragmentation instead of outward mobi-lisation may be taken as a disadvantage for simple access sites, butplays a minor role in complex and deeply impacted molars.

4.1. Complex cases

As Kim et al. (2011) stated, the degree of surgical difculty in-creases as the depth of the impacted tooth increases and its sectionbecomes more difcult. Using magnifying tools, this difculty canbe overcome. 3D e imaging of the case example (Fig. 8) showsclearly that, independently of the degree of impaction, lateral boneremoval can be avoided. The technique describe here has signi-cantly facilitated the removal M3M. The removal of the crown froman occlusal perspective opens the view to the remaining roots andfacilitates the identication as well as the mobilization of rootfragments with a minimum of bone loss. Support endoscopy (SE)has been proven to be a valuable tool when using microelevatorsunder monitor control instead of conventional application withoutdirect vision, in particular when working at close distance to themandibular canal. In combination with 3D imaging based on pre-operative cone beam examination, the depth and location of roottips can be identied by direct probing under magnication. Ac-cording to the experience of both centres, the occlusal approach isof particular value in cases of deeply impacted molars in closecontact with the mandibular canal (see Fig. 8). If required, surgeonswith less experience may extend the bone removal from theocclusal to the lateral aspect of the mandible in order to get accessfor burs mounted in a straight handpiece. Nevertheless the amountof bone removal always can be kept below a critical size withrespect to fracture risk.

4.2. Incidence of nerve lesions

One of the main complications related to M3M removal is tem-porary or permanent disturbance of the sensory function of the IAN.Incidencevariesbetween1.3%and5.3% (Rentonet al., 2005). There is asignicant risk if the root tip is projected onto the mandibular canal.According to Ortiz and San Pedro (2009) the incidence of over-projection is 55.66% and the adjacent position 25.6%. Gen andVasconcellos (2008) reported 23% overprojection and 33% adjacentposition respectively. These gures outline the importance related tothe problem, when minimally invasive surgery is applied. Tolstunovet al. (2011) described a technique to reduce damage of the IAN incases of high-risk patients using pericoronary osteotomy with sec-ondary removal after spontaneous eruption. Of 14 patients, 3 had atemporary neurosensorydysfunction. Landi et al. (2010) also reporteda two-stage technique to assist the eruption. Wang et al. (2012)however suggested an orthodontic approach to reduce the risk ofIAN lesion. It appears obvious, that these approaches only are appli-cable in cases with favourable anatomical conditions to allow furthereruption of the M3M after primary surgery or during orthodontictreatment,which in individual cases cannot bepredicted. The IFTwith

lo-Facial Surgery 42 (2014) 213e219anocclusalminiapasdescribedheredoesnot showan increased risk

W. Engelke et al. / Journal of Cranio-Maxillo-Facial Surgery 42 (2014) 213e219 219for nerve damage compared to conventional procedures although itwas applied in cases with high-risk of neurosensory disturbance.

4.3. Postoperative discomfort

Compared to the results of Kim et al. (2011) the pain level of 2.3vs. 1.7, pain duration 1.95 vs. 1.2 and swelling score 1.38 vs. 0.3 werehigher, but exhibited better values compared with the ap pro-cedures (pail level 6.2, pain duration 4.2, swelling score 2.0) re-ported by the authors. This is remarkable insofar as the durationof surgery was higher (27 vs. 15 min) and the case selection onlyincluded cases of high complexity. The correlation of swelling scorewith duration of surgery and age appears independent of themethod applied. Further controlled clinical studies need to be con-ducted to see if the tendency towards a reduction of postoperativediscomfort using IFT can be conrmed on a larger base of data.

5. Conclusion

The inward fragmentation technique (IFT) with an occlusalminiap approach allows low traumatic access to M3M, exactvisualization of critical structures and results in vertical buccalbone loss below 1 mm. Anatomical integrity in highly complexcases can be maintained with a low complication rate. Specialtechnical resources and specic training is necessary.

Financial supportNo nancial or other study support was received.

DisclosuresOur research, including the Material and methods section of our

manuscript, was approved by our ethical committee in Georg-August-University and Universidad de La Frontera.

Conict of interestThere is no conict of interest (nancially or personally) for any

of the authors.

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Removal of impacted mandibular third molars using an inward fragmentation technique (IFT) Method and first results1 Introduction2 Materials and methods2.1 Surgical procedure2.2 Evaluation

3 Results4 Discussion4.1 Complex cases4.2 Incidence of nerve lesions4.3 Postoperative discomfort

5 ConclusionFinancial supportDisclosuresConflict of interestReferences