***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: 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 Aim To evaluate the effects of autologous platelet rich fibrin gel ( PRF gel ) on bone regeneration following extraction . Material s and Methods The study design was approved by the Institutional Ethical Committee . Study sample consisting of a total of 22 patients requiring bilateral transalveolar third molar extraction s were included after written informed consent . One side was r and omly chosen as case and the other side was the control . Autologous PRF gel was prepared from Fresh blood obtained from the patient . The PRF gel was placed in the extraction site and primary closure was obtained . The patient was called for a follow up on the first post op day , 1st week , one month , three month and six months post op . Regeneration of bone was measured using serial radiographs ( RVG ) at immediate post op , one , three and six months . This was then compared with the bone regeneration seen in the control group , with the radiographs taken at same intervals , to estimate the difference in bone regeneration if any . RVGs were assessed for amount of radiologic bone filling by the method described by Matteo Chiapasco et al. Results and Conclusion Higher mean pixels was recorded in cases compared to controls at all the time intervals viz . , immediate post op , 1 month post op , 3 months post op and 6 months post op . However , the difference in the mean pixels recorded between the two groups was not statistically significant ( P > 0.05 ) . For complete analysis , further follow up of the present patients and a larger sample size is required to obtain a conclusive result of the Bone Regeneration in extraction sockets with PRF gel This radiographic study evaluated the efficacy of different concentrations of rhBMP-2 to regenerate bone in alveolar defects in the anterior maxilla . The study was performed using reasonably st and ardized CT examinations and the Simplant program . The radiographic measurements were further refined by careful st and ardization of the measured regions of interest . There was a statistically significant difference in bone formation between subjects treated with a concentration of 1.5 mg/mL rhBMP-2 compared with each of the other groups . There was no statistically significant difference in bone volume between any of the other groups . None of the groups showed a loss in bone volume AIM To investigate the influence of the use L-PRF as a socket filling material and its ridge preservation properties . MATERIAL S AND METHODS Twenty-two patients in need of single bilateral and closely symmetrical tooth extraction s in the maxilla or m and ible were included in a split-mouth RCT . Treatments were r and omly assigned ( L-PRF socket filling versus natural healing ) . CBCT scans were obtained after tooth extraction and three months . Scans were evaluated by superimposition using the original DICOM data . Mean ridge width differences between timepoints were measured at three levels below the crest on both the buccal and lingual sides ( crest -1 mm ( primary outcome variable ) , -3 mm and -5 mm ) . RESULTS Mean vertical height changes at the buccal were -1.5 mm ( ±1.3 ) for control sites and 0.5 mm ( ±2.3 ) for test sites ( p < 0.005 ) . At the buccal side , control sites values were , respectively , -2.1 ( ±2.5 ) , -0.3 mm ( ±0.3 ) ( p < 0.005 ) and -0.1 mm ( ±0.0 ) , and test sites values were , respectively , -0.6 mm ( ±2.2 ) ( p < 0.005 ) , -0.1 mm ( ±0.3 ) and 0.0 mm ( ±0.1 ) . Significant differences ( p < 0.005 ) were found for total width reduction between test ( -22.84 % ) and control sites ( -51.92 % ) at 1 mm below crest level . Significant differences were found for socket fill ( visible mineralized bone ) between test ( 94.7 % ) and control sites ( 63.3 % ) . CONCLUSION The use of L-PRF as a socket filling material to achieve preservation of horizontal and vertical ridge dimension at three months after tooth extraction is beneficial 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 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 INTRODUCTION The closure of post extraction 
    Output:
    
Alveolar ridge preservation procedures are effective in minimizing post extraction hard tissue dimensional loss .
The outcomes of these procedures are affected by morphology of extraction sockets , type of wound closure , type of grafting material s , use of barrier membranes , and use of growth factors