***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: AIM The aim of the present prospect i ve study was to evaluate the long-term outcome of implants placed simultaneously with guided bone regeneration ( GBR ) using resorbable and non-resorbable membranes . MATERIAL S AND METHODS The original study population consisted of 72 patients receiving a total of 265 implants . In all GBR-treated sites , demineralized bovine bone mineral ( DBBM ) was used in combination either with a collagen ( CM ) or an Exp and ed polytetrafluoroethylene ( e-PTFE ) membrane . A total of 112 implants was treated with CM , 41 implants were treated with e-PTFE membranes , and 112 served as a control group because implants were entirely surrounded by bone and did not need any GBR procedures . Clinical and radiographic analyses were performed after a period of 12 - 14 years . RESULTS The median follow-up time was 12.5 years ( range 12 - 14 years ) . A total of 58 patients participated in the present investigation , corresponding to 80.5 % of the original study population . The cumulative implant survival rate at the follow-up examination was 93.2 % . For the control group the cumulative survival rate was 94.6 % , for the CM 91.9 % , and for the e-PTFE 92.6 % . Differences among the groups were not statistically significant . The radiographically determined marginal bone level ( MBL ) amounted to : control 2.36 mm ( SD ) , CM 2.4 mm ( SD ) , e-PTFE 2.53 mm ( SD ) . There is no evidence ( P < 0.2 ) that the slope of bone level over time is different for the three treatment groups . CONCLUSION It is concluded that implants placed simultaneously with GBR procedures using resorbable or non-resorbable membranes reveal a high survival rate ranging from 91.9 % to 92.6 % , therefore it is considered to be a safe and predictable therapy . [ Correction added after online publication 30 November 2012 : the marginal bone level of CM , e-PTFE , and control was corrected to ' control 2.36 mm ( SD ) , CM 2.4 mm ( SD ) , e-PTFE 2.53 mm ( SD ) ' in the Results section ] OBJECTIVES The aim of this r and omized , controlled clinical trial was to compare the potential of a synthetic bone substitute or a bovine-derived xenograft combined with a collagen membrane to preserve the alveolar ridge dimensions following tooth extraction . METHODS Twenty-seven patients were r and omized into two treatment groups following single tooth extraction in the incisor , canine and premolar area . In the test group , the alveolar socket was grafted with Straumann Bone Ceramic ( SBC ) , while in the control group , Bio-Oss deproteinized bovine bone mineral ( DBBM ) was applied . In both groups , a collagen barrier was used to cover the grafting material . Complete soft tissue coverage of the barriers was not achieved . After 8 months , during re-entry procedures and before implant placement , the horizontal and vertical dimensions of the residual ridge were re-evaluated and trephine biopsies were performed for histological analysis in all patients . RESULTS Twenty-six patients completed the study . The bucco-lingual dimension of the alveolar ridge decreased by 1.1+/-1 mm in the SBC group and by 2.1+/-1 in the DBBM group ( P<0.05 ) . Both material s preserved the mesio-distal bone height of the ridge . No differences in the width of buccal and palatal bone plate were observed between the two groups . The histological analysis showed new bone formation in the apical part of the biopsies , which , in some instances , was in direct contact with both SBC and DBBM particles . The coronal part of the biopsies was occupied by a dense fibrous connective tissue surrounding the SBC and DBBM particles . CONCLUSION Both bio material s partially preserved the width and the interproximal bone height of the alveolar ridge BACKGROUND Reduction of alveolar height and width after tooth extraction may present problems for implant placement , especially in the anterior maxilla where bone volume is important for biologic and esthetic reasons . Different graft material s have been proposed to minimize the reduction in ridge volume . The aim of this study was to compare radiographic and histomorphometric results of magnesium-enriched hydroxyapatite ( MHA ) and calcium sulfate ( CS ) grafts in fresh sockets after tooth extraction s. METHODS Forty-five fresh extraction sockets with three bone walls were selected in 15 patients . A split-mouth design was used : 15 sockets on the right side of the jaw received MHA , 15 sockets on the left side received CS , and 15 r and om unfilled sockets were considered the control ( C ) group . Intraoral digital radiographs were taken at baseline and at 3 months after graft material placement . At 3 months , cylinder bone sample s were obtained for histology and histomorphometry analysis . RESULTS The difference in mean radiographic vertical bone level from baseline to 3 months was -2.48 + /- 0.65 mm in the CS group , -0.48 + /- 0.21 mm in the MHA group , and -3.75 + /- 0.63 mm in the unfilled C group . Statistically significant differences ( P < 0.05 ) were found between CS and MHA groups and between MHA and C groups . Histologic examination revealed bone formation in all treated sites ; trabecular bone assessment did not differ among apical , mesial , and coronal portions of the specimens . Mean vital bone measurements for CS , MHA , and C groups were 45.0 % + /- 6.5 % , 40.0 % + /- 2.7 % , and 32.8 % + /- 5.8 % , respectively . Statistically significant differences ( P < 0.05 ) were found among all groups . Connective tissue percentages averaged 41.5 % + /- 6.7 % for the CS group , 41.3 % + /- 1.3 % for the MHA group , and 64.6 % + /- 6.8 % for the C group . Statistically significant differences ( P < 0.05 ) were found between CS and C groups and between MHA and C groups . The CS-grafted sockets showed 13.9 % + /- 3.4 % residual implant material , whereas the MHA-treated sockets showed 20.2 % + /- 3.2 % residual material . The difference between the groups was statistically significant ( P < 0.05 ) . CONCLUSIONS Radiographs revealed a greater reduction of alveolar ridge in the CS group than in the MHA group . Histologic examination showed more bone formation and faster resorption in the CS group and more residual implant material in the MHA group BACKGROUND The placement of different graft material s and /or the use of occlusive membranes to cover the extraction socket entrance are techniques aim ed at preserving/reducing alveolar ridge resorption . The use of grafting material s in fresh extraction sockets has , however , been question ed because particles of the grafted material have been found in alveolar sockets 6 - 9 months following their insertion . AIM The aims of the study were to ( i ) . evaluate whether alveolar ridge resorption following tooth extraction could be prevented or reduced by the application of a bioabsorbable polylactide-polyglycolide sponge used as a space filler , compared to natural healing by clot formation , and ( ii ) . evaluate histologically the amount and quality of bone tissue formed in the sockets , 6 months after the use of the bioabsorbable material . MATERIAL AND METHODS Thirty-six patients , undergoing periodontal therapy , participated in this study . All patients were scheduled for extraction of one or more compromised teeth . Following elevation of full-thickness flaps and extraction of teeth , measurements were taken to evaluate the distance between three l and marks ( mesio-buccal , mid-buccal , disto-buccal ) on individually prefabricated stents , and the alveolar crest . Twenty-six alveolar sockets ( test ) were filled with a bioabsorbable polylactide-polyglycolide acid sponge ( Fisiograft ) , while 13 sockets ( controls ) were allowed to heal without any filling material . The flaps were sutured with no attempt to achieve primary closure of the surgical wound . Re-entry for implant surgery was performed 6 months following the extraction s. Thirteen biopsies ( 10 test and three control sites ) were harvested from the sites scheduled for implant placement . RESULTS The clinical measurements at 6 months revealed , in the mesial-buccal site , a loss of bone height of 0.2 mm ( 1.4 SD ) in the test and 0.6 mm ( 1.1 SD ) in the controls ; in the mid-buccal portion a gain of 1.3 mm ( 1.9 SD ) in the test and a loss of 0.8 mm ( 1.6 SD ) in the controls ; and in the distal portion a loss of 0.1 mm ( 1.1 SD ) in the test and of 0.8 ( 1.5 SD ) mm in the controls . The biopsies harvested from the test sites revealed that the new bone formed at 6 months was mineralized , mature and well structured . Particles of the grafted material could not be identified in any of the 10 test biopsies . The bone formed in the control sites was also mature and well structured . CONCLUSION The results of this study indicate that alveolar bone resorption following tooth extraction may be prevented or reduced by the use of a bioabsorbable synthetic sponge of polylactide-polyglycolide acid . The quality of bone formed seemed to be optimal for dental implant insertion OBJECTIVES The aim of this study was to compare a nanocrystalline hydroxyapatite ( NCHA ) , NanoBone ( ® ) and a deproteinized bovine bone mineral ( DBBM ) , Bio-Oss ( ® ) with a collagen membrane on the horizontal ridge width alterations following tooth extraction , in addition to histologic aspects of the grafted extraction sockets . MATERIAL AND METHODS In this r and omized clinical trial , 28 symmetrical , non-molar , extraction sockets using a split-mouth design in 12 patients ( eight women and four men ; aged 21 - 60 ; mean 44.6 ± 11.4 years ) , were r and omly selected in the first group to be grafted with DBBM granules covered with a collagen membrane and in the other group grafted with NCHA covered with a collagen membrane . Following extraction horizontal ridge width was measured using caliper and was blindly compared to the dimensions measured prior to implant placement , at the 6- to 8-month follow-up . Subsequently , a 2 × 6 mm trephine core was obtained with aid of acrylic stent and routine histologic preparation was performed on the specimens . RESULTS The width of the DBBM group decreased from 7.75 ± 1.55 to 6.68 ± 1.85 mm ( P < 0.05 ) , whereas the width of the NCHA group decreased from 7.36 ± 1.94 to 6.43 ± 2.08 mm ( P < 0.05 ) . The mean between-group difference did not reach statistical significance ( P = 0.62 ) . Furthermore , histologic and histomorphometric analyses revealed 28.63 ± 12.53 % vital bone in NCHA group vs. 27.35 ± 12.39 % in DBBM group , and no statistically significant difference between the groups ( P = 0.68 ) . CONCLUSION Socket preservation using either NCHA or DBBM in combination with collagen membrane , results in similar , limited horizontal ridge width alterations following tooth extraction TEN PATIENTS WHO REQUIRED two or more anterior teeth extraction s were utilized in this study . Extraction procedures were carried out with a full thickness surgical flap approach . After flap reflection , teeth were removed with a minimum of trauma to the surrounding bone . Following extraction silicone-based impression techniques were used to produce a model of the alveolar process and small metal pins were placed in the alveolus to be used as fixed points to make measurements of ridge dimensions . One socket was covered with an exp and ed polytetrafluoroethylene ( ePTFE ) barrier membrane ( experimental site ) ; the other socket was a conventional control . The soft tissue flaps were then mobilized using periosteal releasing incision and the wound closed with ePTFE mattress sutures . Six months following extraction , patients were treated with flap surgery to expose both extraction s sites to remove the ePTFE membranes and to measure ridge dimensions using the pins as fixed points . Clinical and model measurements have shown statistically significant better ridge dimensions at experimental sites than at control ( P < or = 0.05 ) . Three patients with exposed membranes had similar dimensional changes as controls . Results from this study suggested that this improved technique offers a predictable alveolar ridge maintenance enhancing the bone quality for dental implant procedures and esthetic restorative dentistry BACKGROUND Flapless extraction of teeth allows for undisturbed preservation of the nearby periosteum and a source of osteoprogenitor cells . Recombinant human bone morphogenetic protein 2 ( rhBMP-2 ) has been used for different bone augmentation purpose s with great osteoinductive capacity . The aim of this study is to compare the bone regenerative ability of rhBMP-2 on an absorbable collagen sponge ( ACS ) carrier to a collagen sponge ( CS 
    Output:
    
GBR and socket filler presented similar SE for survival/success rates and average marginal bone loss .
There is limited evidence to support the clinical benefit of ARP over USH in improving implant-related outcomes despite a decrease in the need for further ridge augmentation during implant placement .
Similar implant placement feasibility , survival/success rates and marginal bone loss should be anticipated following ARP or USH .
Currently , it is not clear which type of ARP intervention has a superior impact on implant outcomes