***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: Healing of the extraction socket after tooth removal involves retention of the blood clot followed by a sequence of events that lead to changes in the alveolar process in a three dimensional fashion . This normal healing event results in a minimal loss of vertical height ( around 1 mm ) , but a substantial loss of width in the buccal-lingual plane ( 4 - 6 mm ) . During the first three months following extraction that loss has been shown to be significant and may result in both a hard tissue and soft tissue deformity affecting the ability to restore the site with acceptable esthetics . Procedures that reduce the resorptive process have been shown to be predictable and potentially capable of eliminating secondary surgery for site preparation when implant therapy is planned . The key element is prior planning by the dental therapist to act at the time of extraction to prevent the collapse of the ridge due to the loss of the alveolus . Several techniques have been employed as ridge preservation procedures involving the use of bone grafts , barrier membranes and biologics to provide a better restorative outcome . This review will explore the evidence behind each technique and their efficacy in accomplishing site preparation . The literature does not identify a single technique as superior to others ; however , all accepted therapeutic procedures for ridge preservation have been shown to be more effective than blood clot alone in r and omized controlled studies OBJECTIVE To volumetrically evaluate soft tissue changes of different ridge preservation techniques compared to spontaneous healing 6 months after tooth extraction . MATERIAL S AND METHODS In each of 40 patients , one single-rooted tooth was extracted and four treatment modalities were r and omly assigned to the following groups ( n = 10 each ) : A ) ß-tricalcium-phosphate-particles with a polylactid coating ( ß-TCP ) , B ) demineralized bovine bone mineral with 10 % collagen covered with a collagen matrix ( DBBM-C/CM ) , C ) DBBM with 10 % collagen covered with an autogenous soft tissue punch graft ( DBBM-C/PG ) , D ) spontaneous healing ( control ) . Impressions were obtained before extraction and 6 months later , casts were digitized and volumetric changes at the buccal soft tissues were determined . One-way anova was performed and pair-wise Wilcoxon rank sum test with Bonferroni-Holm method was applied for comparison of differences between two groups . RESULTS After 6 months , horizontal contour changes accounted for -1.7 ± 0.7 mm ( A ) , -1.2 ± 0.5 mm ( B ) , -1.2 ± 0.7 mm ( C ) and -1.8 ± 0.8 mm ( D ) . None of the group comparisons reached statistical significance . CONCLUSIONS Six months after tooth extraction all groups revealed a horizontal volume change in the buccal soft tissue contour . Application of DBBM-C/CM or DBBM-C/PG reduced the amount of volume resorption compared to ß-TCP or spontaneous healing without reaching statistically significant difference PURPOSE This r and omized clinical trial was conducted to assess the safety and effectiveness of the ErhBMP-2 in alveolar bone regeneration as well as preservation of the β-TCP bone graft material that contains ErhBMP-2 . MATERIAL S AND METHODS This study involved 72 patients at the 3 study centers . The patients , who were divided into 2 groups : the experiment group who had ErhBMP-2 coated TCP/HA and the control group who had TCP/HA graft material alone transplanted immediately after tooth extraction . CT was taken before and 3 months after the transplantation and healing status was compared between the two groups . The efficacy endpoints that were used to measure the degree of bone induction included alveolar bone height and 3 measurements of bone width . The paired t test was used to determine the significance of the changes ( P<.05 ) . RESULTS Changes in alveolar bone height were -1.087 ± 1.413 mm in the control group and -.059 ± 0.960 mm in the experimental group ( P<.01 ) . At 25 % extraction socket length [ ESL ] , the changes were 0.006 ± 1.149 mm in the control group and 1.279 ± 1.387 mm in the experimental group . At 50 % ESL , the changes were 0.542 ± 1.157 mm and 1.239 ± 1.249 mm , respectively ( P<.01 for 25 % ESL , and P<.05 for 50 % ESL ) . During the experiment , no adverse reactions to the graft material were observed . CONCLUSION ErhBMP-2 coated β-TCP/HA were found to be more effective in preserving alveolar bone than conventional β-TCP/HA alloplastic bone graft material The aim of the study was to determine the fate of demineralized freeze-dried bone allograft ( DFDBA ) used in conjunction with a barrier membrane in the management of extraction sockets and deficient alveolar ridges , and to compare the amount of bone formed with that found in untreated sites . Ten biopsies were obtained from 8 grafted patients . Five biopsies were harvested from untreated sites during routine implant placement and analyzed for comparison . In the socket management procedure , DFDBA was packed tightly into the socket and covered with an exp and ed polytetrafluoroethylene ( e-PTFE ) membrane . Primary closure was achieved in all cases . In the ridge regeneration procedure , cortical columns were placed in the ridge projecting outward approximately 3 mm to create and maintain space for DFDBA particles packed between them ; the columns were then covered by an e-PTFE membrane .  Healing time ranged from 8 to 23 months . At the time of implant placement , bone cores ( 7 mm x 2 mm ) were harvested , fixed in 10 % formalin solution , and prepared for histologic examination . At the light microscopic level , no inflammation or fibrous encapsulation was observed . New bone formation on and around DFDBA particles was widespread . Histomorphometric analysis of the grafted specimens and untreated sites was carried out using the trabecular bone volume ( TBV ) index . The TBV in the maxillary test specimens was 55.03 % , as compared to 57.33 % of control cores . Unaltered DFDBA made up 8.7 % of the test specimens . In the m and ibular biopsies , the TBV was 56.6 % , while for the controls it was 40.9 % . The volume of DFDBA still present was 2.45 % . The results tended to indicate that treatment with DFDBA in conjunction with cell occlusive membranes will result in new bone formation , predominantly by the process of conduction , which appears to be similar in amount and nature to that found in cores harvested from healed nonfunctional edentulous areas OBJECTIVES The aim of the following study was to assess contour changes after socket preservation techniques . MATERIAL AND METHODS In five beagle dogs , the distal root of the third and fourth m and ibular premolars was extracted . The following treatments ( Tx ) were r and omly assigned for the extraction socket . Tx 1 : BioOss Collagen . Tx 2 : BioOss Collagen and a free soft tissue graft . Tx 3 : No treatment . Tx 4 : The internal buccal aspect was covered with an experimental collagen membrane , the extraction socket was filled with BioOss Collagen and the membrane folded on top of the graft . Impressions were obtained at baseline , 2 and 4 months after surgery . Bucco-lingual measurements were performed using digital imaging analysis . RESULTS All groups displayed contour shrinkage at the buccal aspect . Only the differences between the two test groups ( Tx 1 , Tx 2 ) and the control group ( Tx 3 ) were significant at the buccal aspect ( p < or = 0.001 ) . No measurements of the Tx 4 group could be performed . CONCLUSION Socket preservation techniques , used in the present experiment , were not able to entirely compensate for the alterations after tooth extraction . Yet , incorporation of BioOss Collagen seems to have the potential to limit but not avoid the post-operative contour shrinkage 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 and Purpose : The resorption of alveolar bone following tooth extraction results in a narrowing and shortening of the residual ridge , which leads to esthetic and restorative problems , and reduces the bone volume available for implant therapy . The aim of this study was to evaluate the prevention of alveolar collapse after tooth extraction , using titanium membrane ( Frios Boneshield ; DENTSPLY Friadent , Mannheim , Germany ) , associated ( or not ) with autologous bone graft . Material s and Methods : A total of 10 nonsmoking healthy subjects , ranging from 35 to 60 years old , were selected for this study . Each patient had a minimum of 2 uni-radicular periodontally hopeless teeth , which were scheduled for extraction . After the procedure , 2 titanium pins were fixed on the vestibular bone surfaces that were used as references for the initial measures ( depth , width , and height ) of the socket . Of the sockets,1 was r and omly chosen to be filled with autologous bone graft ( test ) removed from superior maxillary tuber , and the other one did not receive the graft ( control ) . A titanium membrane was adapted and fixed , covering the sockets , which remained for at least 10 weeks . After a 6-month healing , the final measures were performed . Results : There was exposure of the membrane in 5 of the 10 treated subjects . Average bone filling ( ±st and ard deviation ) among the 10 subjects was 8.80 ± 2.93 mm ( range 4 - 13 ) in the control group and 8.40 ± 3.35 mm ( range 4 - 13 ) in the test group . Average bone loss in width in both group was 1.40 ± 1.97 mm ( range −4 - 1 ) in the control group and 1.40 ± 0.98 mm ( range −4 - 0 ) in the test group . There was no significant statistical difference between groups considering the evaluated st and ards . Conclusion : The use of titanium membrane , alone or in association with autogenous bone , favored the prevention of alveolar ridge after tooth extraction . This membrane seems to be a possible and safe alternative to other nonresorbable membranes when the prevention of alveolar ridge resorption is the objective The aim of this study was to compare the effectiveness of two bone substitute material s for socket preservation after tooth extraction . Extraction sockets in 10 patients were filled with either inorganic bovine bone material ( Bio-Oss ) or with synthetic material consisting of hydroxyapatite and silicon dioxide ( NanoBone ) . Extraction sockets without filling served as the control . The results demonstrate the effectiveness of the presented protocol for socket preservation and 
    Output:
    
After flapless extraction of teeth , and using a minimum healing period of 12 weeks as a temporal measure , xenografts and allografts result ed in the least loss of socket dimensions compared to alloplasts or sockets with no grafting .
Histologic outcomes after a minimum of 12 weeks of healing showed that sockets grafted with alloplasts had the maximum amount of vital bone and the least amount of remnant graft material and remnant connective tissue .
There is a limited but emerging body of evidence for the predictable regeneration of deficient buccal bone with socket grafting material s , need for barrier membranes , use of tissue engineering , and use of autogenous soft tissue grafts from the palate to cover the socket