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◊PageD1 Dental Tribune Middle East & Africa Edition | 1/2017 IMPLANT TRIBUNE D2 gion 34–44) with four 8.0mm long titanium microscrews (Storz am Mark GmbH, EmmingenLiptingen, Germany; Fig. 8). A combination of autogenous bone chips and particu- lated xenograft (BEGO OSS, BEGO Implant Systems, Bremen, Germa- ny) was placed in the small remain- ing space between the bone block and the alveolar processus, as well as around and on the bone graft. The augmented site was covered with a platelet rich in growth factors (PRGF) membrane (BTI Biotechnology Insti- tute, Blue Bell, USA) and additionally with a barrier membrane for guided bone regeneration (GBR, Bio-Gide, Geistlich Biomaterials Vertriebsge- sellschaft mbH, Baden-Baden, Ger- many; Fig 9). The healing of the graft was uneventful and without any complications, like membrane ex- posure, being classified as a frequent post-operative complication.5 The patient was provided with a remov- ableprovisionalprosthesis. Re-entryandimplantsurgery The re-entry for the delayed implant placement protocol was planned af- ter a healing period of four months. With regard to the soft aspect of the augmentedareaoftheanteriorman- dible, the dimensions of the alveolar ridge appeared sufficient enough for implant placement (Fig. 10). The CBCT data confirmed the assump- tion, demonstrating a significant gain of bone volume in the interfo- raminal region of the mandible after augmentation. The horizontal thickness of the cr- estal alveolar bone was 5.53mm in region44and4.43inregion32. The augmentation procedure result- ed in a horizontal bone gain of about 3.9 mm in region 44 and 3.3mm in region 32 respectively, representing a mean bone gain of 3.6mm (Fig. 11). After elevating the flap, an appar- ently good osseointegration and stabilisation of the autograft with the underlying pristine bone could be noticed (Fig. 12). Prior to implant placement, the fixation screws were removed. The four implants with a diameter of 3.75mm and a length of 11.5mm (BEGO Semados® RSX, BEGO Im- plant Systems) were inserted epi- crestally in regions 33, 31, 41 and 43 using the freehand-method without asurgicalguide(Fig.13).Theinsertion torque of the implants was 35Ncm withgoodprimarystability. Pre-prosthetic surgery and prostheticrehabilitation After three months of uneventful submerged healing, the panoramic X-ray showed a successful implant osseointegration without any signs of bone resorption (Fig. 14). Due to a lack of keratinised gingiva, we de- cidedforanenlargementoftheratio between attached and free gingiva by performing muco-gingival sur- gerywiththeEdlan-Mejcharmethod (Figs. 15, 16 & 17). After an additional healing period of one month, the fi- nal bar retained, a removable acrylic overdenture was incorporated. The bar was constructed with bar abut- ments (PS TiBA, BEGO Implant Systems) and a non-precious alloy (Wirobond®, BEGO Dental, Bremen) and was screw-retained on the four implants(Figs.18,19&20). Discussion In our case presentation, the patient suffered from an extremely hori- zontal bone resorption, resulting in a 1.0–3.0mm thin, and knife-edged alveolar crest. Since standard diam- eter dental implants need a certain crestal bone volume for an adequate stabilisation and a good and predict- able osseointegration, augmenta- tionprocedureshadtobeperformed priortoimplanttreatment.6 A recently published meta-analysis showed that dental implant survival has probably to be seen indepen- dently of the biomaterial used in augmentation procedures.7, 8 Since this evidence is limited by the fact, that defect size, augmented volume, and regenerative capacity are scarce- ly well described in literature, autog- enous bone is still recommended as the‘goldstandard’foraugmentation inthedeficientalveolarridge.Simul- taneous grafting and augmentation is the standard procedure in ridge augmentation, resulting in an ex- tendedoperatingtime.3 Fortunately, as the vertical dimen- sion of the anterior mandible was high enough in our clinical case, we were able to harvest an adequate au- togenous bone block from the thin alveolar crest, in order to use it as an onlay graft for the horizontal aug- mentation of the anterior mandible. This procedure avoided donor site morbidity, and resulted in less op- erating time and a reduced patient discomfort. The dimensions of the graft were ideal for lateral augmentation, so that there was no need for any ad- ditional carving of the bone block. As mean bone gain after healing of the autogenous graft was 3.6mm in our patient, it was slightly smaller compared to the average bone gain of 4.3mm, as reported in a system- atic review by Jensen and Terheyden in 2009,5 but was comparable to the findings of a recent review by Sanz- Sanchez et al., showing a mean bone gain in horizontal defects of 3.9mm inastagedapproach.9 Nonetheless,wegainedenoughbone volume for insertion of four stand- ard diameter implants. Considering the fact that the fixation screws had to be removed, and with regard to a number of benefits of a delayed im- plant placement in augmented de- ficient alveolar ridges, we opted for a two-stage protocol. Even though delayed implant placement with flap elevation required a second sur- gical intervention and therefore an additional burden for the patient, it comprised the additional advantage of a visual and tactile assessment with respect to the osseointegration of the autograft in our patient case. Another crucial advantage of the stagedapproachcomprisedinteralia the possibility for an implant place- mentinanidealpositionforthelater prosthetic restoration under visual control.5 Another reason for open access for implant placement was the use of non-resorbable microscrews for the stabilisation of the bone graft. The decision to utilise non-resorbable titanium screws in favour to resorb- able screws out of poly (D,L-lactide) acid, was supported by the find- ings of a systematic review of the CochraneCollaboration.6 Thus, resorbable screws seem to have a high susceptibility for frac- ture during fixation of onlay grafts. As the combination of autogenous grafts with guided bone regenera- tion (GBR) is apparently associated with superior outcomes, we decided touseabarriermembrane.9 With the additional application of a PRGF membrane, we aimed to uti- lise the beneficial effects of platelet- derived rich plasma for an advanced woundtherapy,andthereducedrisk ofpost-operativeinfection.10 Theves- tibuloplasty with the Edlan-Mejchar method was performed for two pur- poses. Firstly it was done in order to create a sufficient amount of kerati- nised mucosa. According to findings of a systematic review, published by Linetal.,alackofkeratinisedmucosa around implants fosters plaque ac- cumulation,inflammation,andsoft- tissuerecession.11 Secondlyweaimed to create enough space for the final overdenture. Conclusion The staged approach with the use of an autogenous bone graft, harvested from the surgical site in the anterior mandible, resulted in a significant horizontal bone gain, and took to a good osseointegration of both, au- tograft and implants. Obviously, the describedgraftingprocedurehasnot been previously reported in litera- ture. Despite the lack of any experi- ence reports, our method revealed nonetheless a successful rehabili- tation with an implantsupported, screw-retained prosthetic rehabilita- tion, and is still in function without any biological or technical problems afterathree-yearfollowup. SpecialthankstoDrPantelisPetraka- kis. Editorial note: A list of references is availablefromthepublisher The article was published in CADCAM Magazine International Magazine of digitalDentistry4/2016 Fig. 3: Pre-operative clinical aspect of the an- terioralveolarridge. Fig. 14: After three months of submerged healing, a successful implant osseointegra- tion without bone resorption was visible on thepanoramicX-ray. Fig.7:Aspect of theboneharvest. Fig. 18: Facial view of the bar construction andPSTiBAabutments. Fig.11:TheCBCTshortlybeforere-entrydem- onstrated a significant gain of bone volume afteraugmentation. Fig. 5: Preparation of the osseous graft with themicrosaw. Fig. 16: After uncovering the implants, an Edlan-Mejchar plastic surgery was performed todeepen thevestibulum. Fig. 9: The osseous graft was covered with a PRGF membrane and a barrier membrane for GBR. Fig. 20: After an additional healing period of one month after muco-gingival surgery, the barwasinserted. Fig. 4: After elevation of the mucoperiostal flap, the sharp-edged alveolar ridge becomes visible. Fig. 15: Soft-tissue condition of the anterior alveolar crest at the time of implant-uncover- ing:lackofkeratinisedgingiva. Fig. 8: The graft was fixed with four minis- crews. Fig.19:Oralviewof thebar. Fig. 12:After flap elevation, a good osseointe- grationandstabilisationoftheautograft was noticed. Fig.6:Detachment of thegraft withachisel. Fig.17:Aspect afterplasticsurgery. Fig.10:Sufficient horizontalridgedimensions afterahealingperiodoffourmonths. Fig.21:Finalprostheticrestaurationoftheup- perandlowerjaw. Fig. 13: After the fixation screws were re- moved, the four implants with a diameter of 3.75 mm and a length of 11.5 mm were insertedepicrestallywithout asurgicalguide. DrMarkoNikolic ArtdentalClinic Tometici1d Kastav,Croatia Tel.:+38551582888 info@artdental.hr