Lateral Ridge Augmentation Using Allograft Blocks and Guided Bone Regeneration for Implant Sites
Phase: NA
Conditions: Alveolar Ridge Augmentation
Sponsor: University of Bern

 
 
Study topic: Lateral Ridge Augmentation Using Allograft Blocks and Guided 
Bone Regeneration for Implant Sites 
 
 
Date:08/12/18 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Study Summary 
Background: 
Clinicians are increasingly faced with the challenge of reconstructing the alveolar ridge as 
more patients desire fixed implant-supported restorations. Reconstruction of large 
horizontal alveolar defects still remains a challenge in implantology. Although autogenous 
blocks from intraoral sites are proven effective for such defects, donor site morbidity and 
limited graft availability are major limitations. Allogenic bone blocks have been proposed to 
overcome these limitations, however, the outcomes reported in the literature are 
inconclusive. Several case series (Acceturi 2002, Petrungaro 2005, Nissan 2008) claim 
successful ridge augmentation with allogenic bone, whereas others revealed higher failure 
rates due to bone exposure and graft resorption (Chiapasco 2013, Lumetti 2014, Spin-Neto 
2013). In addition, allogenic bone blocks exhibit a higher degree of resorption (Spin-Neto 
2013, Lumetti 2014), whereas Novell (2012), showed that resorption of allografts was 
comparable to autogenous bone blocks. Randomized clinical trials state that bone 
resorption occurs but does not deter successful placement of implants in augmented sites 
(Deluiz 2016, Amorfini 2014). This case series aims to evaluate the efficacy of allogenic 
blocks for lateral augmentation of atrophic ridges for implant sites, over a three-year period.  
Materials and methods: In nineteen edentulous sites, cortico-cancellous allogenic blocks 
(PHOENIX, TBF, France) were shaped to the defect and screw-fixated. A double-layer of 
autogenous chips and demineralized bovine bone (Bio-Oss, Geistlich Pharma AG, 
Switzerland) was used to fill the voids. The augmented site was covered by non-cross-linked 
collagen membrane (Bio-Gide, Geistlich Pharma AG, Switzerland). After a healing period of 9 
months, implants were placed and CBCT analysis was performed post-implantation. 
Following a period of 34 months of function, patients were clinically and radiographically re-
examined. The primary outcome measure is the graft stability that is measured by change in 
lateral ridge width over time. Secondary outcome measures are various soft tissue 
parameters around the implant. 
 
Study Protocol 
Technique:  
The present study design is a mono-center three-year follow-up case series study to 
examine the safety and effectiveness of allograft bone blocks combined with guided bone 
regeneration (GBR). The study is in accordance to the principles of the Declaration of 
Helsinki and will obtain approval by the standing ethical committee of the state of Bern, 
Switzerland. 
The preoperative analysis includes a complete medical history, clinical examination of the 
dentition and a thorough analysis of the implant recipient using 3D cone beam computed 
tomography (3D Accuitomo 170, Morita, Kyoto, Japan). 
Surgical Procedure: 
The surgical procedures wil be done in two stages. In the first stage surgery, a full-thickness 
mucoperiosteal flap will be raised on both the facial and palatal aspects. Ridge 
augmentation will be done using a mineralized, cortico-cancellous, delipidized, lyophilized 
allogenic block (ALB; PHOENIX allograft, TBF Mions, France). Following hydration of the ALB, 
the cortico-cancellous part of the block will be shaped to fit the recipient site and fixated by 
two fixation screws (Medartis, Modus, Mediartis Holding AG, Basel, Switzerland). Voids 
around the ALB will be filled with autogenous bone chips (AGB) harvested locally from the 

recipient site. The augmented site will be covered by a first layer of deproteinized bovine 
bone mineral mixed (DBBM; Bio- Oss, Geistlich Pharma, Wolhusen, Switzerland and a non-
crosslinked collagen membrane (BG; Bio- Gide, Geistlich AG, Wolhusen, Switzerland) as 
described previously (Chappuis 2017). A periosteal-releasing incision will be used to provide 
tension-free flap closure. The wound margins will be approximated using non-resorbable 
poly- amide suture (Seralon, Serag-Wiessner GmbH, Naila, Germany) to obtain primary 
wound closure. All patients will be prescribed an antibiotic regimen with 2g of amoxicillin 
with clavulanic acid 1 hour preoperatively to be continued as 1g twice daily for 3 days post-
surgery. Patients will be also prescribed analgesics and chlorhexidine digluconate (0.2%) for 
chemical plaque control. In patients with post-surgical complications the antibiotic regimen 
will be prolonged. Sutures will be removed around 14 days postoperatively. Removable 
provisionals will be adapted, but patients will be instructed to not to wear them unless 
unavoidable during the initial healing phase. 
The second stage surgery will be performed after a minimal healing period of six months. A 
paracrestal incision will be given to elevate a full thickness mucoperiosteal. The fixation 
screws from the previous surgery will be removed and the implant bed will be prepared 
based on the specific requirements of the site. All implants placed will have chemically 
modified, sandblasted, and acid-etched surface and will have either, a tissue level implant 
(TL) or a bone level implant (BL) design (SLActive, Straumann AG, Basel, Switzerland). 
Simultaneous re-grafting will be performed as required using autogenous bone chips, DBBM 
and a non-cross-linked collagen membrane. A tension-free wound closure will be obtained 
by non-resorbable sutures. The antibiotic and analgesic regimen and post-surgical care will 
be the same as in the first-stage surgery. Sutures will be removed after 14 days. Patients will 
be instructed to wear the provisional with caution. After a healing period of 4-6 months the 
healing abutments will be placed for the future prosthetics. The implants will be restored 
with either different prosthetic solutions as required. Patient will be given oral hygiene 
instructions and directed to enroll onto a supportive periodontal therapy to monitor oral 
health. 
Clinical and radiographic follow-up examination after 3 years: 
Clinical parameters - Updates on medical conditions, smoking, oral hygiene and enrollment 
in a maintenance care program will be collected from the patients. Clinical examinations will 
be made by the same examiner throughout the three-year follow-up period. The clinical 
parameters will be assessed as previously described (Chappuis 2017): peri-implant 
suppuration, modified plaque index (mPLI), modified sulcus bleeding index (mBLI), probing 
depth, DIM (distance from the implant shoulder to the mucosal margin), width of the KM, 
mobility and full mouth plaque scores. 
Radiographic analysis using 2D radiographs and 3D CBCT - The peri-implant bone loss will be 
measured on periapical 2D radiographs analyzing the proximal DIB values as the vertical 
distance from the implant shoulder to the first bone-to-implant contact as described earlier 
(DIB; mm) (Weber HP et al 1992). The mean DIB value per implant considered will the 
average of the mesial and distal values. 
The horizontal bone gain of the atrophic sites will be assessed by with the smallest field of 
view (3D Accuitomo 170, Morita, Kyoto, Japan). The image analysis will be performed by a 
high-resolution screen, using a specialized software (i-Dixel, Morita, Kyoto, Japan). The 3D 
analysis included a preoperative analysis of the proposed implant site. A standard reference 
point, 4mm crestal to the shoulder of the future implant will be used for all measurements 
(Chappuis 2017). CBCT measurements will be repeated prior to implant placement, using 

the same reference point and repeated again at the 2-3year follow-up appointment. The 
radiographic measurements will be done by one examiner. 
Assessment of biological, technical complications and patient reported outcome measures 
(PROMS) - All events of complications, intra-operative and post-operative at each surgical 
phase (graft surgery and implant surgery), prior to prosthetic treatment and post prosthetic 
rehabilitation both operator-assessed and self-reported will be recorded. 
Patient reported outcome measures will be assessed by the Oral Health Impact Profile 
(OHIP) scores and patient satisfaction scores based on a visual analog scale (VAS) will be 
recorded for each patient after the entire treatment is completed and the patients receive 
the prosthetic replacements. 
 
 
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