***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Two techniques of ridge augmentation using onlay bone graft alone or associated with a non-resorbable membrane have been previously described . This prospect i ve , r and omized study compared these two techniques at 6 months , in terms of bone gain , resorption and quality  obtained at edentulous sites .  Osseous measurements were taken using stents , callipers and CT-scans . Membrane exposure occurred at one site , 4 weeks after placement .  Endosseous implants  were successfully placed at all grafted sites . The mean graft thickness for all subjects was 4.7 mm ( range : 2.3 - 6.2 mm ) . Overall mean resorption was 1.5 mm ( range : 0 - 4.6 mm ) whereas overall mean width gain was 3.2 mm ( range : 0.8 - 6.2 mm ) . Six months following surgery , the membrane group experienced significantly less bone resorption than the graft alone group ( P<0.01 ) . Width augmentation did not differ significantly between the two groups . In conclusion , combining a membrane with an onlay graft demonstrates less bone resorption with a minimal risk of complications . Longer follow-up is needed to confirm the benefits of using a non-resorbable membrane STATEMENT OF PROBLEM No study provides human histologic evidence regarding the use of resorbable collagen membrane for a 2-stage localized alveolar augmentation procedure . PURPOSE The purpose of this pilot study was to evaluate the potential of use of a resorbable collagen membrane in conjunction with an autogenous bone graft and inorganic bovine mineral ( IBM ) for labial/buccal alveolar ridge augmentation prior to placing dental implants . Material and methods Seven consecutively treated human patients participated in the study . All patients received labial/buccal alveolar ridge augmentation .  An autogenous block graft was secured at the recipient site with fixation screws and a mixture of autogenous particulate with IBM was placed at the periphery . Resorbable collagen membrane was used as a barrier . Radiographic and laboratory measurements were made to quantify ridge augmentation and resorption rate . Preoperative and postoperative stone casts were used to quantify alveolar ridge augmentation . Volumetric evaluation was measured in mL whereas linear laboratory evaluation was measured in millimeters . Measurements were made 1 and 6 months after bone grafting . Histologic and histomorphometric analysis from the grafted area evaluated new bone formation , and osteoconductivity of IBM .  RESULTS For all patients Type II to III bone quality was achieved at the augmented sites . The implant survival rate was 100 % at second-stage surgery . No complication was observed at the recipient sites . Radiographic evaluation revealed 4.65 mm labial/lingual augmentation , whereas laboratory analysis revealed 4.57 mm . Volumetric laboratory analysis demonstrated 1.00 ( + /- 0.29 ) mL alveolar ridge augmentation 6 months after bone grafting and 13.79 % resorption between months 1 and 6 . Histomorphometric analysis revealed that on average , the area occupied by bone was 34.28 % ( range 24 to 50 ; + /-9.05 ) , ] soft tissue 46.00 % ( + /-9.20 % ; range 30 % to 55 % ) , and IBM particles 19.71 % ( + /-11.74 % , range 3 % to 42 % ) . The proportion of the surface of the IBM particles in contact with bone was 47.14 % ( range 15 % to 64 % ; SD 17.21 % ) . CONCLUSIONS Resorbable collagen membranes may be used as barriers for labial/buccal alveolar ridge augmentation procedures BACKGROUND AND AIM To assess the success rate of  implants placed in atrophic ridges , regenerated by means of block bone grafts harvested from iliac crest , calvaria or intraoral donor sites ( m and ibular ramus , chin ) . METHODS AND MATERIAL S A systematic review of all prospect i ve and retrospective studies analyzing the success rate of  implants placed simultaneously or as a second surgery following ridge augmentation by means of onlay graft technique , compared with implants placed in pristine bone , was performed . To be included , studies had to involve at least five consecutively treated patients and to report clearly specified success criteria . It was also necessary a minimum follow-up period of six months , to allow the observation of potential biological complications during function , rather than early implant failures . In order to assess the success rate of implants in terms of health of periimplant tissues , implant stability , osteointegration and bone resorption , studies reporting only the survival rate of implants , were excluded . RESULTS From 323 potentially relevant studies , 65 full-text publications were screened and eight were identified as fulfilling the inclusion criteria . The success rate of  implants  placed in onlay graft regenerated ridges ranged from 72,8 % to 97 % after follow-up periods ranging from 6 months to 10 years , with all the studies but two , reporting a success rate higher than 84 % ( range 84 - 97 % ) . CONCLUSION The obtained data demonstrated that the success rate of implants placed in regenerated areas are very similar to those obtained in case of implants placed in pristine bone , and suggested that onlay graft augmentation is a quite predictable technique to allow the placement of implants in severely atrophic areas . Despite that , the current review revealed that there are not many studies providing data on the success rate of dental implants placed in onlay graft augmented ridges and demonstrated , on average , a poor method ological quality . So r and omized controlled studies adopting st and ardized criteria to define success and failure of implants are required and data from this review must be considered indicative Bone grafting may be required prior to implant placement , at the time of implant placement , or subsequent to it . The aim of this study was to compare the healing of onlay block grafts  when deproteinized bovine bone coverage was used with the healing of the grafts without such coverage . The purpose was a clinical evaluation of deproteinized bovine bone 's ability to reduce grafted bone resorption . The results indicated that bovine bone can be placed over grafted areas , taking advantage of its osteoconductive properties and compensating for the natural bone resorption caused by remodeling OBJECTIVES The purpose s of this study were to compare : ( a ) autogenous bone grafts ( ABG ) and distraction osteogenesis ( DO ) for their ability in correcting vertically deficient m and ibular ridges and their capability in maintaining over time the vertical bone gain obtained before and after implant placement ; and ( b ) the survival and success rates of implants placed in the reconstructed or distracted areas . MATERIAL AND METHODS In a 2-year period ( 2001 - 2002 ) , 17 patients presenting with vertically atrophied partially edentulous m and ibles requiring implant-supported prosthetic rehabilitation , were included in this study . Patients were r and omly assigned to two groups . Eight patients ( group 1 ) were treated with ABG harvested from the m and ibular ramus , while nine patients ( group 2 ) were treated by means of DO . In group 1 , patients received implants 4 - 5 months after the reconstructive procedure , while in group 2 implants were placed at the time of distraction device removal ( approximately 3 months after the completion of distraction ) . A total of 19 endosseous implants were placed in group 1 , and 21 implants were placed in group 2 patients . For both groups , after an additional 3 - 5-month period , prosthetic rehabilitation was started . RESULTS Bone resorption before implant placement was significantly higher in group 1 ( P=0.01 ) , while no statistically significant differences were found between the two groups as far as survival and success rates of implants and peri-implant bone resorption after the start of prosthetic loading were concerned . CONCLUSION The results suggested that : ( a ) both techniques may effectively improve the deficit of vertically resorbed edentulous ridges ; ( b ) survival and success rates of implants placed in the reconstructed/distracted areas are consistent with those of implants placed in native bone PURPOSE The objectives of this study were ( 1 ) to compare the stability , evaluated by means of resonance frequency analysis ( RFA ) , of implants placed posterior m and ibles augmented with autogenous bone harvested from the m and ibular symphysis with that of  implants placed in nongrafted edentulous posterior m and ibles and ( 2 ) to compare peri-implant marginal bone height changes and implant failure for the 2 groups . MATERIAL S AND METHODS Eight patients with thin posterior m and ibular ridges ( buccolingual crestal width less than 4 mm ) underwent labial onlay alveolar grafting with symphyseal bone blocks 4 months prior to placement of 17 implants . Seven nongrafted patients received  18 implants in the edentulous posterior m and ible ; these patients served as a control group . RFA was performed the day of implant placement ( baseline ) , 1 month postplacement , 4 months postplacement ( after prosthesis delivery ) , and 12 months postloading . Peri-implant bone height changes at a level of 0.01 mm were assessed using periapical radiographs at baseline , the 1-month follow-up , and the 4-month follow-up . Analysis of variance was used to evaluate statistical differences within the groups , and t test was used to make comparisons between groups . RESULTS None of the patients presented postoperative complications or implant failure . Mean implant stability quotient ( ISQ ) was 63.0+/-6.0 to 70.2 + /-3.5 for the grafted group and 64.1+/-4.1 ISQ to 70.1+/-3.9 for the nongrafted group . No significant difference was found in mean ISQ between the grafted and nongrafted groups at baseline , the 1-month follow-up , 4 months postplacement , or 12 months postloading ( P = .211 , P = .873 , P = .925 , P = .735 , respectively ) . Mean peri-implant bone loss was 0.16 + /- 0.04 mm mesially and 0.16 + /- 0.05 mm distally . CONCLUSION RFA revealed no difference in implant stability between m and ibular ridges augmented with autologous bone grafts at baseline or after loading OBJECTIVES To assess in a r and omized- clinical trial the influence of three augmentation techniques ( chinbone with or without a Bio-Gide membrane and Bio-Oss with a Bio-Gide membrane ) on the clinical and radiographic characteristics of hard and soft tissues around implants and adjacent teeth in the reconstructed maxillary anterior region , up to 1 year after functional loading . MATERIAL S AND METHODS Ninety-three patients requesting single-tooth replacement and presenting with a horizontal ( bucco-palatinal ) bone deficiency were included . After augmentation , 93 ITI-Esthetic(Plus ) implants were placed . Clinical variables , st and ardized photographs and radiographs were analysed to assess the impact on the levels of the marginal gingiva ( MGL ) and marginal bone ( MBL ) around implants and adjacent teeth , viz at pre-augmentation , pre-implantation ( TPI ) and 1 ( T(1 ) ) and 12 ( T(12 ) ) months after final crown placement . RESULTS Implant survival was 97.8 % . No significant differences were observed in the treatment outcomes of the three augmentation modalities . Combining the three modalities , a slight but significant increase in the implants approximal pocket depth was found between T(1 ) and T(12 ) . Approximal bone loss at the implant between T(1 ) and T(12 ) was 0.14 + /- 0.76 mm ( mesial ) and 0.14 + /- 0.47 mm ( distal ) ; the approximal MGL slightly increased ( mesial : 0.24 + /- 0.46 mm , distal : 0.25 + /- 0.66 mm ) , and the buccal MGL decreased ( 0.11 + /- 0.61 mm ) . Bone loss at the adjacent teeth , although minor , was significant between TPI and T(1 ) . No correlations were observed in changes of MBL and MGL . CONCLUSIONS None of the three applied augmentation technique procedures influenced the characteristics of the MGL and MBL or the implant survival of single-tooth replacements . Peri-implant hard and soft tissues were very stable in the first year after loading AIM The aim of the present study was to evaluate if the use of deprotenized bovine bone mineral ( DBBM ) and collagen barrier membranes ( CM ) in combination with m and ibular bone block grafts could reduce bone block graft resorption during healing . METHODS A prospect i ve r and omized controlled study has been design ed . Twenty-two ridges presenting horizontal alveolar deficiency ( crest width < 4 mm ) and at least two adjacent missing teeth were included in the study . In the control group , one or multiple m and ibular blocks were used to gain horizontal augmentation of the ridge . In the test group , DBBM granules were added at the periphery and over the graft . The reconstructions were covered by two layers of CM . Implants were placed 4 months after grafting . Direct measurements of crest width were performed before and immediately after bone augmentation , and immediately before implant placement . RESULTS Statistical analysis showed no significant differences in crest width between test and control groups at baseline and immediately after grafting . Mean augmentation at first surgery in the test group 
    Output:
    
CONCLUSIONS Survival and success rates of implants placed in horizontally and vertically resorbed edentulous ridges reconstructed with block bone grafts are similar to those of implants placed in native bone , in distracted sites or with guided bone regeneration .
More surgical challenges and morbidity arise from vertical augmentations , thus short implants may be a feasible option