***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: BACKGROUND Placement of implants  with a minimally invasive flapless approach has the potential to minimize crestal bone loss , soft tissue inflammation , and probing depth adjacent to implants and to minimize surgical time . PURPOSE The aim of this multicenter study was to evaluate implant placement using a minimally invasive one-stage flapless technique up to 2 years . MATERIAL S AND METHODS Fifty-seven patients ranging in age from 24 to 86 years were recruited from three clinical centers ( Tucson , AZ , USA ; Tel Aviv , Israel ; Göteborg , Sweden ) . Seventy-nine implants were placed . A small , sharp-tipped guiding drill was used to create a precise , minimally invasive initial penetration through the mucosa and into bone ( Nobel Biocare , Yorba , Linda , CA , USA ) . Implants were placed according to the manufacturer 's instructions , with minimal countersinking . The parameters evaluated were total surgical time , implant survival , bone quality and quantity , implant position by tooth type , depth from mucosal margin to bone crest , implant length , probing depth , inflammation , and crestal bone changes . At 2 years , for 79 implants placed in 57 patients , the cumulative success rate using a minimally invasive flapless method was 98.7 % , indicating the loss of 1 implant . Changes in crestal bone for 77 baseline and follow-up measurements were insignificant ( radiograph 1 : mean 0.7 mm , SD 0.5 mm , range 2.8 mm , minimum 0.2 mm , maximum 3.0 mm ; radiograph 2 : mean 0.8 mm , SD 0.5 mm , range 3.4 mm , minimum 0.12 mm , maximum 3.5 mm ) . Using descriptive statistics for 78 patients ( one implant lost ) , mean changes for probing depth and inflammation were clinical ly insignificant . The average time for implant placement was 28 minutes ( minimum 10 minutes , maximum 60 minutes , SD 13.1 minutes ) . Average depth from mucosal margin to bone was 3.3 mm ( SD 0.7 mm , minimum 2 mm , maximum 5 mm , range 3 mm ) . Thirty-two implants were placed in maxillae and 47 in m and ibles . CONCLUSIONS The results of this study demonstrate that following diagnostic treatment planning criteria , flapless surgery using a minimally invasive technique is a predictable procedure . The benefits of this procedure are lessened surgical time ; minimal changes in crestal bone levels , probing depth , and inflammation ; perceived minimized bleeding ; and lessened postoperative discomfort PURPOSE This prospect i ve study aim ed to examine postoperative dimensional changes in the buccal bone and mucosa around  single-stage implants placed in the posterior region . MATERIAL S AND METHODS The dimensions of peri-implant tissue around  screw-type implants  placed in the posterior region were examined at surgery ( baseline ) and 6 months and 1 year after surgery . The lateral contour of the buccal bone and mucosa was horizontally measured at five vertical heights at 1-mm intervals ( + 1 to -3 mm from the implant platform ) using custom- design ed instruments . Bone resorption on the proximal sides was assessed on radiographs . Mucosal recession was measured on plaster casts of the dentition . RESULTS Sixty-six implants placed in 30 patients were examined . All implants were clinical ly osseointegrated and stable throughout the study period . The buccal bone exhibited horizontal resorption throughout the study period , even at the most apical height measured . Assessed at each height , thicker bone ( > 2 mm thick ) tended to exhibit horizontal resorption during the first 6 months after surgery . However , the bone resorbed horizontally by approximately 0.4 mm during the final 6 months , irrespective of its contour . Vertical resorption of the buccal marginal bone was approximately 1 mm during the period from 6 months to 1 year . The bone-retaining group at the 1-year time point was found to have thicker bone walls at baseline compared with the bone-loss group . The thickness of the buccal mucosa showed little change . There was no obvious correlation between buccal bone resorption and mucosal recession . CONCLUSIONS The buccal bone exhibited both horizontal and vertical resorption over the year after surgery . The initial contour of the bone was significantly associated with bone retention or loss at 1 year . However , mucosal recession was not directly affected by buccal bone resorption OBJECTIVES The aim of this prospect i ve study was to evaluate dimensional alterations of the peri-implant tissues at  single-tooth restorations  from the time of implant placement to 1-year post-loading . MATERIAL AND METHODS Eleven patients , aged 18 - 36 years , subjected to single-tooth replacements with implant-supported restorations ( Brånemark implant system ) in the maxillary anterior region were included in the analysis . The implant installation was performed as a two-stage procedure with a 6-month healing interval . Bone dimensions were determined by direct assessment s immediately following implant placement and at abutment connection . The prosthetic restoration was placed approximately 1 month after abutment surgery . Radiographic and clinical examinations were performed at crown placement and at 1-year post-loading . Assessment s of the soft tissues at the implant site and at the neighboring teeth were performed before and during implant placement , before abutment connection , after crown placement and at the 1-year follow-up examination . Mean values and st and ard deviations were calculated for each variable and interval , with the subject as the statistical unit . RESULTS At the time of abutment connection , a mean loss of bone height at the facial and lingual aspect of the implant amounting to 0.7 - 1.3 mm ( P < 0.05 ) was recorded , whereas no significant change was noted at proximal sites . A mean reduction of 0.4 mm of the labial bone thickness was observed between implant placement and the second-stage surgery . The radiographic bone-to-implant level showed a mean loss of 0.9 mm between abutment connection and crown placement ( P<0.05 ) and a further 0.7 mm loss at 1 year ( P < 0.05 ) . The thickness of the labial mucosa was increased at crown placement followed by a slight remission at 1 year . During the corresponding interval , a mean apical displacement of the labial soft tissue margin of 0.6 mm had taken place ( P < 0.05 ) . A papilla fill of > or = 50 % was observed at a frequency of 32 % at crown placement and 86 % at 1 year . CONCLUSIONS The results demonstrated that following implant surgery remodeling takes place , which is manifested in diminished bone dimensions , both horizontally and vertically , at the facial aspect of the implant . The observed soft tissue alterations after the crown placement may affect the esthetic appeal of the restorative therapy AIM The aim of this study was to evaluate and compare the radiographic bone loss and soft tissue parameters around one stage and two stage implants . MATERIAL S AND METHODS Twenty four patients with submerged implants and twenty four patients with non submerged implants at the time of loading were assessed in this prospect i ve cohort study . The soft tissue assessment included probing depth ( PD ) , papilla index ( PI ) , mucosal thickness ( MT ) and keratinized tissue ( KG ) ; another parameter assessed was the radiographic distance between the shoulder of the implant and alveolar crest evaluated at baseline ( loading time ) and 3,6 and 12 months after loading in both groups . Data were analysed using repeated measures analysis of variance ( ANOVA ) and multiple comparisons were done using LSD method . RESULTS The changes in the soft tissues including PD , KG , MT and PI had no significant differences in either group . The amount of bone loss 3 and 6 months after loading was significantly greater in one stage implants ( 0.93±0.45 mm at 3months and 1.45±0.58 mm at 6months , for one stage and 0.32±0.21 mm at 3months and 0.74±0.43 mm at 6 months for two stage group ) . But the change of this index 12 months later was not significantly different between the two groups ( 1.87±0.76 mm for one stage and 1.65±0.59 mm for two stage group ) . CONCLUSION Based on the results of this study there is no difference in hard and soft tissue changes one year after loading of one or two stage implants PURPOSE This prospect i ve r and omized matched-pair controlled trial aim ed to evaluate marginal bone levels and soft tissue alterations at implants restored according to the platform-switching concept with a new inward-inclined platform and compare them with external-hexagon implants . MATERIAL S AND METHODS Traditional external-hexagon ( control group ) implants and inward-inclined platform implants ( test group ) , all with the same implant body geometry and 13 mm in length , were inserted in a st and ardized manner in the posterior maxillae of 40 patients .  Radiographic bone levels were measured by two independent examiners after 6 , 12 , and 18 months of prosthetic loading . Buccal soft tissue height was measured at the time of abutment connection and 18 months later . RESULTS After 18 months of loading , all 80 implants were clinical ly osseointegrated in the 40 participating patients . Radiographic evaluation showed mean bone losses of 0.5 ± 0.1 mm ( range , 0.3 to 0.7 mm ) and 1.6 ± 0.3 mm ( range , 1.1 to 2.2 mm ) for test and control implants , respectively . Soft tissue height showed a significant mean decrease of 2.4 mm in the control group , compared to 0.6 mm around the test implants . CONCLUSIONS After 18 months , significantly greater bone loss was observed at implants restored according to the conventional external-hexagon protocol compared to the platform-switching concept . In addition , decreased soft tissue height was associated with the external-hexagon implants versus the platform-switched implants OBJECTIVES This r and omized-controlled trial aim ed to evaluate marginal bone level alterations at implants restored according to the platform-switching concept , using different implant/abutment mismatching . MATERIAL AND METHODS Eighty implants  were divided according to the platform diameter in four groups : 3.8 mm ( control ) , 4.3 mm ( test group(1 ) ) , 4.8 mm ( test group(2 ) ) and 5.5 mm ( test group(3 ) ) , and r and omly placed in the posterior maxilla of 31 patients . After 3 months , implants were connected to a 3.8-mm-diameter abutment and final restorations were performed . Radiographic bone height was measured by two independent examiners at the time of implant placement ( baseline ) , and after 9 , 15 , 21 and 33 months . RESULTS After 21 months , all 80 implants were clinical ly osseointegrated in the 31 patients treated . A total of 69 implants were available for analysis , as 11 implants had to be excluded from the study due to early unintentional cover screw exposure . Radiographic evaluation showed a mean bone loss of 0.99 mm ( SD = 0.42 mm ) for test group(1 ) , 0.82 mm ( SD = 0.36 mm ) for test group(2 ) and 0.56 mm ( SD = 0.31 mm ) for test group(3 ) . These values were statistically significantly lower ( P<0.005 ) compared with control ( 1.49 mm , SD = 0.54 mm ) . After 33 months , five patients were lost to follow-up . Evaluation of the remaining 60 implants showed no difference compared with 21 months data except for test group(2 ) ( 0.87 mm ) and test group(3 ) ( 0.64 mm ) . There was an inverse correlation between the extent of mismatching and the amount of bone loss . CONCLUSIONS This study suggested that marginal bone level alterations could be related to the extent of implant/abutment mismatching . Marginal bone levels were better maintained at implants restored according to the platform-switching concept A data subset from an ongoing prospect i ve multicenter clinical study of threaded hydroxyapatite-coated implants was evaluated to assess safety and efficacy of the implants when used to support fixed prostheses in the posterior m and ible . Observations were recorded before surgery , at first-stage surgery , at second-stage surgery , at loading , and at quarterly postrestoration prophylactic exams and annual comprehensive patient visits . Implant failure criteria included  mobility , radiographic evidence of bone loss greater than one-third the length of the implant or peri-implant radiolucency , fracture , exfoliation , removal for any reason , and patient reported pain upon palpation . Soft tissue indices were monitored as part of the study . Postrestoration implant performance was analyzed using life-table methodology . From the 2,062 implants restored in 720 patients in the parent study , a total of 423 implants in 195 patients were included in the posterior m and ibular data subset . Thirteen implants failed at or before second-stage surgery for a surgical success rate of 96.9 percent . Prosthodontics was completed , and one or more postrestoration annual follow-up visits occurred for 314 implants as of the interim analysis cutoff date . Fourteen implants failed during an observation period extending up to 62 months after completion of prosthodontic treatment . One failed implant was removed , whereas the 13 remaining implants are 
    Output:
    
At present , there is insufficient evidence to answer the question on the differences in clinical outcome in terms of CBL between implants placed in sites with initial soft tissue thickness < 2 mm and those with ≥2 mm .