human
***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The purpose of this clinical investigation was to compare the new resorbable collagen membrane , Bio-Gide , to the conventional exp and ed polytetrafluoroethylene material ( Gore-Tex ) for guided bone regeneration in situations involving exposed implant surfaces . Over a 2-year period , 25 split-mouth patients were treated r and omly : one defect site was treated with Bio-Gide and the other defect site with Gore-Tex ; all 84 defects were filled with Bio-Oss and covered with the respective membrane . The defect types , their dimensions , and their morphology were measured in detail initially and at re-entry to allow for calculation of the exposed implant surface . Changes in defect surface for both types of membranes were statistically significant ( P < .0001 ) ; however , no statistical significance ( P > .94 ) could be detected between the two membranes . The mean average percentage of bone fill was 92 % for Bio-Gide and 78 % for Gore-Tex sites . In the latter group , 44 % wound dehiscences and /or premature membrane removal occurred . The resorbable membrane , Bio-Gide , in combination with a bone graft , can be a useful alternative to the well-established exp and ed polytetrafluoroethylene membranes 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 PURPOSE This study evaluated predictability and treatment outcome of the combined application of autografts and exp and ed-polytetrafluoroethylene ( e-PTFE ) membranes for lateral ridge augmentation in partially edentulous patients using a staged approach . MATERIAL S AND METHODS Forty partially edentulous patients were consecutively treated . Emphasis was given to a lateral incision technique , perforation of the cortex to open the marrow cavity , stable placement of corticocancellous autografts and bone chips , precise adaptation of the e-PTFE membranes and stabilization with miniscrews , and a tension-free primary soft tissue closure . After 7 to 13 months , the sites were reopened for membrane removal and implant placement . RESULTS All but one patient showed complication-free soft tissue healing . After reopening , 38 patients exhibited excellent ridge augmentation , whereas two had compromised results , with soft tissue encapsulation of some bone chips . None of the applied block grafts showed clinical signs of resorption . Preaugmentation and postaugmentation measurements showed an enlargement of the crest width from a mean of 3.5 mm to 7.1 mm . This allowed the placement of nonsubmerged titanium implants in all 40 patients . CONCLUSIONS The current study demonstrates that the combined application of autografts and e-PTFE membranes is a predictable surgical procedure for lateral ridge augmentation that results in an enlargement of the alveolar crest in partially edentulous patients . The autografts support the membrane and activate bone formation with their osteoconductive and osteoinductive properties . The membrane acts as a physical barrier to nonosteogenic soft tissue cells , and protects the autografts against resorption during healing A problem with using autogeneic bone for onlay grafting is its degree of incorporation and volumetric persistence . This study explored whether improved graft volumetric maintenance can be achieved by recombinant human bone morphogenetic protein-2 ( rhBMP-2 ) and whether a combination of rhBMP-2 and osteopromotive membranes is advantageous in this respect . Unicortico-cancellous bone grafts were positioned below the temporal muscle bilaterally in 48 adult Lewis rats . The recipient bone was ground , and the grafted area was r and omly treated according to one of eight different alternatives . Two doses of rhBMP-2 ( 4 microg/80 microl or 32 microg/80 microl buffer ) in a collagenous carrier were tested , with or without coverage with exp and ed polytetrafluoroethylene membranes . As controls , membrane and carrier , alone or in combination , and onlay grafts only were used . The results were evaluated after 4 and 20 weeks by routine histologic examination and immunohistochemical labeling for various bone and cartilage matrix proteins . After 4 weeks , rhBMP-2-treated grafts showed complete integration , whereas for controls , only the membrane-alone group attained incorporation after 20 weeks . The combined treatment with high-dose rhBMP-2 and membrane demonstrated , as compared with the remaining rhBMP-2 groups , pronounced bone formation and less graft resorption , result ing in maintained or increased graft size . This was observed after 4 weeks , and the result remained at 20 weeks . Treatment with high-dose rhBMP-2 without membrane placement , in contrast , result ed in extensive resorption and graft size reduction at 20 weeks . Control groups showed less success in graft size persistence . It was concluded that a combination of high-dose rhBMP-2 and osteopromotive membranes had a synergistic effect , leading to rapid , complete graft integration and size maintenance . In the absence of a membrane , the protein seemed to accelerate the remodeling of the graft BACKGROUND It is not uncommon for the placement of endosseous dental implants  in the maxillary posterior jaw region to be complicated by the pneumatization of the maxillary sinus . When this occurs , the residual bone between the floor of the sinus and the crestal ridge is inadequate for the placement of implants . The sinus lift procedure provides a way to increase the amount of available bone and the placement of longer implants . METHODS One hundred twenty ( 120 ) implants were placed in 45 augmented maxillary sinuses . Patients ranged in age from 34 to 78 years . The implant design included a limited number of non-hydroxyapatite (HA)-coated titanium screws , with the majority of the implants being HA-coated cylinders , grooved cylinders , and screws . The augmentation material s were autogenous bone , allogenic bone ( demineralized freeze-dried bone allograft , DFDBA ) , alloplastic bone ( HA ) , combination grafts of HA and DFDBA , and combination grafts of autogenous bone and DFDBA . All the cases were successfully restored with implant-supported , bar-retained overdentures or fixed partial dentures . The follow-up began at Stage 2 uncovering and ranged from 5 to 71 months , with a mean of 38.2 and st and ard deviation of 14.6 months . RESULTS Three ( 2.5 % ) of the 120 implants failed between the period of implant placement and 36 months . Failures appeared to be associated with a history of smoking . Other complications encountered during the study are presented . Implant survival was higher in those placed in grafted sinuses ( 97.5 % ) than in those placed in the posterior maxilla without sinus grafting ( 90.3 % ) . CONCLUSION These findings support the use of implants placed in augmented sinuses to support dental prostheses The aim of this study was to analyse the clinical outcome of two different surgical methods for the reconstruction of narrow edentulous ridges before implant installation : guided bone regeneration with e-PTFE membranes and autologous bone chips or grafting of autologous bone blocks without e-PTFE membranes .  Thirty partially edentulous patients , presenting insufficient bone width ( less than 4 mm ) in the edentulous sites for installation of screw-type titanium implants  , were selected and assigned to two different treatment modalities . Fifteen patients ( group 1 ) were treated by means of guided bone regeneration with e-PTFE membranes supported by stainless steel screws and autologous bone chips taken from intraoral sites . Fifteen patients ( group 2 ) were treated by means of autologous bone blocks taken from intraoral or extraoral sites ( anterior iliac crest and calvaria ) and stabilized with titanium microscrews . Six to 8 months later , during re-entry for implant insertion , the gain of ridge width obtained was measured . In group 1 the average amount of bone gain was 2.7 mm , whereas in group 2 the value was 4.0 mm . Five to 6 months after implant placement prosthetic rehabilitation was started . The mean follow-up after prosthetic load has been 22.4 months . Success rates of implants according to Albrektsson criteria has been 93.3 % in group 1 , and 90.9 % in group 2 . Although a statistical comparison between the two treatment modalities may not be feasible , due to the bias result ing from the choice of treatment by the clinician and from the differences in donor sites and defect extension , some considerations can be made : 1 ) both methods are a reliable means for the correction of narrow edentulous ridges ; 2 ) both techniques necessitate overcorrection of the defect because of interposition of connective tissue beneath the membrane in the first group and bone resorption in the second one ; 3 ) the use of semipermeable barriers increases the costs of the surgical procedure , as compared to bone grafting without membranes ; 4 ) guided bone regeneration presents a higher risk of infection because of wound dehiscence and membrane exposure . Therefore , in case of wide edentulous areas , reconstruction of narrow ridges should be performed with bone blocks without membranes The purpose of this study was to compare the regenerative response of autogenous cortical and cancellous bone chips and a natural particulate resorbable bone mineral ( RBM ) ( Bio-Oss , Geistlich-Pharma , Wolhusen , Switzerl and ) in st and ardized bony defects relating paranasal sinuses to one another and to bone blocks . On 13 skeletally mature female goats four st and ardized critical-sized full thickness bone defects were made in the frontal bone overlying the frontal sinus . These defects were filled at r and om with cortical bone chips , cancellous bone chips , spongiosa granules of a RBM or left empty . Fluorochrome bone markers were injected subcutaneously 1 and 5 weeks after transplantation , and one week before the animals were killed . The animals were killed at 3 , 6 , 12 and 24 weeks after surgery . Autogenous cancellous bone chips is the material of choice for bridging a bony defect in the maxillofacial area where there is no need for mechanical strength . They heal in the same way as cancellous bone blocks do . Cortical bone chips are not reliable enough to be used as a solitary bone-grafting material under these conditions . A cortical block as a solitary implant gives better results . RBM granules as solitary implant in a critical-sized defect do not stimulate osteoconduction but give rise to an extensive osteoclastic activity stimulated by the mutual loose relation . A solid block of RBM is in a similar case more reliable 
    Output:
    
agent
***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The purpose of this clinical investigation was to compare the new resorbable collagen membrane , Bio-Gide , to the conventional exp and ed polytetrafluoroethylene material ( Gore-Tex ) for guided bone regeneration in situations involving exposed implant surfaces . Over a 2-year period , 25 split-mouth patients were treated r and omly : one defect site was treated with Bio-Gide and the other defect site with Gore-Tex ; all 84 defects were filled with Bio-Oss and covered with the respective membrane . The defect types , their dimensions , and their morphology were measured in detail initially and at re-entry to allow for calculation of the exposed implant surface . Changes in defect surface for both types of membranes were statistically significant ( P < .0001 ) ; however , no statistical significance ( P > .94 ) could be detected between the two membranes . The mean average percentage of bone fill was 92 % for Bio-Gide and 78 % for Gore-Tex sites . In the latter group , 44 % wound dehiscences and /or premature membrane removal occurred . The resorbable membrane , Bio-Gide , in combination with a bone graft , can be a useful alternative to the well-established exp and ed polytetrafluoroethylene membranes 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 PURPOSE This study evaluated predictability and treatment outcome of the combined application of autografts and exp and ed-polytetrafluoroethylene ( e-PTFE ) membranes for lateral ridge augmentation in partially edentulous patients using a staged approach . MATERIAL S AND METHODS Forty partially edentulous patients were consecutively treated . Emphasis was given to a lateral incision technique , perforation of the cortex to open the marrow cavity , stable placement of corticocancellous autografts and bone chips , precise adaptation of the e-PTFE membranes and stabilization with miniscrews , and a tension-free primary soft tissue closure . After 7 to 13 months , the sites were reopened for membrane removal and implant placement . RESULTS All but one patient showed complication-free soft tissue healing . After reopening , 38 patients exhibited excellent ridge augmentation , whereas two had compromised results , with soft tissue encapsulation of some bone chips . None of the applied block grafts showed clinical signs of resorption . Preaugmentation and postaugmentation measurements showed an enlargement of the crest width from a mean of 3.5 mm to 7.1 mm . This allowed the placement of nonsubmerged titanium implants in all 40 patients . CONCLUSIONS The current study demonstrates that the combined application of autografts and e-PTFE membranes is a predictable surgical procedure for lateral ridge augmentation that results in an enlargement of the alveolar crest in partially edentulous patients . The autografts support the membrane and activate bone formation with their osteoconductive and osteoinductive properties . The membrane acts as a physical barrier to nonosteogenic soft tissue cells , and protects the autografts against resorption during healing A problem with using autogeneic bone for onlay grafting is its degree of incorporation and volumetric persistence . This study explored whether improved graft volumetric maintenance can be achieved by recombinant human bone morphogenetic protein-2 ( rhBMP-2 ) and whether a combination of rhBMP-2 and osteopromotive membranes is advantageous in this respect . Unicortico-cancellous bone grafts were positioned below the temporal muscle bilaterally in 48 adult Lewis rats . The recipient bone was ground , and the grafted area was r and omly treated according to one of eight different alternatives . Two doses of rhBMP-2 ( 4 microg/80 microl or 32 microg/80 microl buffer ) in a collagenous carrier were tested , with or without coverage with exp and ed polytetrafluoroethylene membranes . As controls , membrane and carrier , alone or in combination , and onlay grafts only were used . The results were evaluated after 4 and 20 weeks by routine histologic examination and immunohistochemical labeling for various bone and cartilage matrix proteins . After 4 weeks , rhBMP-2-treated grafts showed complete integration , whereas for controls , only the membrane-alone group attained incorporation after 20 weeks . The combined treatment with high-dose rhBMP-2 and membrane demonstrated , as compared with the remaining rhBMP-2 groups , pronounced bone formation and less graft resorption , result ing in maintained or increased graft size . This was observed after 4 weeks , and the result remained at 20 weeks . Treatment with high-dose rhBMP-2 without membrane placement , in contrast , result ed in extensive resorption and graft size reduction at 20 weeks . Control groups showed less success in graft size persistence . It was concluded that a combination of high-dose rhBMP-2 and osteopromotive membranes had a synergistic effect , leading to rapid , complete graft integration and size maintenance . In the absence of a membrane , the protein seemed to accelerate the remodeling of the graft BACKGROUND It is not uncommon for the placement of endosseous dental implants  in the maxillary posterior jaw region to be complicated by the pneumatization of the maxillary sinus . When this occurs , the residual bone between the floor of the sinus and the crestal ridge is inadequate for the placement of implants . The sinus lift procedure provides a way to increase the amount of available bone and the placement of longer implants . METHODS One hundred twenty ( 120 ) implants were placed in 45 augmented maxillary sinuses . Patients ranged in age from 34 to 78 years . The implant design included a limited number of non-hydroxyapatite (HA)-coated titanium screws , with the majority of the implants being HA-coated cylinders , grooved cylinders , and screws . The augmentation material s were autogenous bone , allogenic bone ( demineralized freeze-dried bone allograft , DFDBA ) , alloplastic bone ( HA ) , combination grafts of HA and DFDBA , and combination grafts of autogenous bone and DFDBA . All the cases were successfully restored with implant-supported , bar-retained overdentures or fixed partial dentures . The follow-up began at Stage 2 uncovering and ranged from 5 to 71 months , with a mean of 38.2 and st and ard deviation of 14.6 months . RESULTS Three ( 2.5 % ) of the 120 implants failed between the period of implant placement and 36 months . Failures appeared to be associated with a history of smoking . Other complications encountered during the study are presented . Implant survival was higher in those placed in grafted sinuses ( 97.5 % ) than in those placed in the posterior maxilla without sinus grafting ( 90.3 % ) . CONCLUSION These findings support the use of implants placed in augmented sinuses to support dental prostheses The aim of this study was to analyse the clinical outcome of two different surgical methods for the reconstruction of narrow edentulous ridges before implant installation : guided bone regeneration with e-PTFE membranes and autologous bone chips or grafting of autologous bone blocks without e-PTFE membranes .  Thirty partially edentulous patients , presenting insufficient bone width ( less than 4 mm ) in the edentulous sites for installation of screw-type titanium implants  , were selected and assigned to two different treatment modalities . Fifteen patients ( group 1 ) were treated by means of guided bone regeneration with e-PTFE membranes supported by stainless steel screws and autologous bone chips taken from intraoral sites . Fifteen patients ( group 2 ) were treated by means of autologous bone blocks taken from intraoral or extraoral sites ( anterior iliac crest and calvaria ) and stabilized with titanium microscrews . Six to 8 months later , during re-entry for implant insertion , the gain of ridge width obtained was measured . In group 1 the average amount of bone gain was 2.7 mm , whereas in group 2 the value was 4.0 mm . Five to 6 months after implant placement prosthetic rehabilitation was started . The mean follow-up after prosthetic load has been 22.4 months . Success rates of implants according to Albrektsson criteria has been 93.3 % in group 1 , and 90.9 % in group 2 . Although a statistical comparison between the two treatment modalities may not be feasible , due to the bias result ing from the choice of treatment by the clinician and from the differences in donor sites and defect extension , some considerations can be made : 1 ) both methods are a reliable means for the correction of narrow edentulous ridges ; 2 ) both techniques necessitate overcorrection of the defect because of interposition of connective tissue beneath the membrane in the first group and bone resorption in the second one ; 3 ) the use of semipermeable barriers increases the costs of the surgical procedure , as compared to bone grafting without membranes ; 4 ) guided bone regeneration presents a higher risk of infection because of wound dehiscence and membrane exposure . Therefore , in case of wide edentulous areas , reconstruction of narrow ridges should be performed with bone blocks without membranes The purpose of this study was to compare the regenerative response of autogenous cortical and cancellous bone chips and a natural particulate resorbable bone mineral ( RBM ) ( Bio-Oss , Geistlich-Pharma , Wolhusen , Switzerl and ) in st and ardized bony defects relating paranasal sinuses to one another and to bone blocks . On 13 skeletally mature female goats four st and ardized critical-sized full thickness bone defects were made in the frontal bone overlying the frontal sinus . These defects were filled at r and om with cortical bone chips , cancellous bone chips , spongiosa granules of a RBM or left empty . Fluorochrome bone markers were injected subcutaneously 1 and 5 weeks after transplantation , and one week before the animals were killed . The animals were killed at 3 , 6 , 12 and 24 weeks after surgery . Autogenous cancellous bone chips is the material of choice for bridging a bony defect in the maxillofacial area where there is no need for mechanical strength . They heal in the same way as cancellous bone blocks do . Cortical bone chips are not reliable enough to be used as a solitary bone-grafting material under these conditions . A cortical block as a solitary implant gives better results . RBM granules as solitary implant in a critical-sized defect do not stimulate osteoconduction but give rise to an extensive osteoclastic activity stimulated by the mutual loose relation . A solid block of RBM is in a similar case more reliable 
    Output:
    