***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 aim of this study of the present experiment was to study the marginal periimplant tissues at intentionally non-submerged ( 1-stage implants ) and initially submerged and subsequently exposed implants ( 2-stage implants ) . 5 beagle dogs , about 1-year-old , were used , 3 months after the extraction of the m and ibular premolars , fixtures of the Astra Tech Implants Dental System , the Brånemark System and the Bonefit -- ITI system were installed . In each m and ibular quadrant , 1 fixture of each implant system was installed in a r and omised order . The installation procedure followed the recommendations given in the manuals for each system . Thus , following installation , the bone crest coincided with the fixture margin of the Astra Tech Implants Dental System and the Brånemark System , whereas the border between the plasma sprayed and the machined surface of the Bonefit-ITI implant system was positioned at the level of the bone crest . Following a healing period of 3 months , abutment connection was carried out in the 2-stage systems ( the Astra Tech Implants Dental System and the Brånemark system ) . A 6-month period of plaque control was initiated . The animals were sacrificed and biopsies representing each important region dissected . The tissue sample s were prepared for light microscopy and exposed to histometric and morphometric measurements . The mucosal barrier which formed to the titanium surface following 1-stage and 2-stage implant installations comprised an epithelial and a connective tissue component , which for that 3 systems studied , had similar dimensions and composition . The amount of lamellar bone contained in the periimplant region close to the fixture part of the 3-implant systems was almost identical . It is suggested that correctly performed implant installation may ensure proper conditions for both and hard tissue healing , and that the geometry of the titanium implant seems to be of limited importance OBJECTIVE Our purpose was to measure the agreement , reliability , construct validity , and feasibility of a measurement tool to assess  systematic review s ( AMSTAR ) . STUDY DESIGN AND SETTING We r and omly selected 30 systematic review s from a data base . Each was assessed by two review ers using : ( 1 ) the enhanced quality assessment question naire ( Overview of Quality Assessment Question naire [ OQAQ ] ) ; ( 2 ) Sacks ' instrument ; and ( 3 ) our newly developed measurement tool ( AMSTAR ) . We report on reliability ( interobserver kappas of the 11 AMSTAR items ) , intraclass correlation coefficients ( ICCs ) of the sum scores , construct validity ( ICCs of the sum scores of AMSTAR compared with those of other instruments ) , and completion times . RESULTS The interrater agreement of the individual items of AMSTAR was substantial with a mean kappa of 0.70 ( 95 % confidence interval [ CI ] : 0.57 , 0.83 ) ( range : 0.38 - 1.0 ) . Kappas recorded for the other instruments were 0.63 ( 95 % CI : 0.38 , 0.78 ) for enhanced OQAQ and 0.40 ( 95 % CI : 0.29 , 0.50 ) for the Sacks ' instrument . The ICC of the total score for AMSTAR was 0.84 ( 95 % CI : 0.65 , 0.92 ) compared with 0.91 ( 95 % CI : 0.82 , 0.96 ) for OQAQ and 0.86 ( 95 % CI : 0.71 , 0.94 ) for the Sacks ' instrument . AMSTAR proved easy to apply , each review taking about 15 minutes to complete . CONCLUSIONS AMSTAR has good agreement , reliability , construct validity , and feasibility . These findings need confirmation by a broader range of assessors and a more diverse range of review PURPOSE To evaluate whether platform switching could preserve marginal bone around implants up to 6 months after loading . MATERIAL S AND METHODS 15 patients were selected for a r and omised controlled trial . Each patient received one customised wide body implant , with the external hex connection located eccentrically , allowing an extra 1 mm switch on one side . The hex was positioned at r and om at the mesial or distal side and the implant was loaded after 6 months of non-submerged healing . Patients were examined at 3 , 6 and 12 months after surgery , during which a radiograph was taken to evaluate bone levels . At 12 months , the mucosal thickness was measured using a perio-probe . RESULTS All implants survived and the mean overall bone loss , calculated from both the switched and non-switched side , was 0.39 mm ( SD 0.33 , range 0.00 - 1.45 ) , 0.85 mm ( SD 0.59 , range 0.10 - 2.50 ) and 0.80 mm ( SD 0.46 , 0.26 - 1.89 ) after 3 , 6 and 12 months , respectively . The bone loss continued up to 6 months but stabilised thereafter ( P = 0.615 ) . Significantly more bone loss was observed at the non-switched side compared to the switched side at 3 months ( 0.51 mm versus 0.28 mm , P = 0.019 ) , 6 months ( 1.05 mm versus 0.64 mm , P = 0.002 ) and 12 months ( 0.94 mm versus 0.66 mm , P = 0.002 ) . The mean mucosal thickness was 4.22 mm ( SD 1.45 ; range 1.50 - 7.00 ) , and was not significantly different between the switched and non-switched sides ( P = 0.882 ) . However , using a post-hoc analysis with the mean thickness as a threshold , the mean bone loss was only significantly different between switched and non-switched sides when the mucosa was thicker than 4.22 mm ( P = 0.036 ) . CONCLUSIONS The outcome of this r and omised trial is in accordance with earlier studies suggesting that that platform switching decreases bone loss by 30 % . Although the sample size was limited , it seems that the creation of a biologic width affects peri-implant bone loss to a significant extent and that platform switching is only effective when the mucosal thickness allows the establishment of a biologic width 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 OBJECTIVE to compare the soft and hard tissue healing and remodeling around tissue-level implants with different neck configurations after at least 1 year of functional loading . MATERIAL AND METHODS eighteen patients with multiple missing teeth in the posterior area received two implants inserted in the same sextant . One test ( T ) implant with a 1.8 mm turned neck and one control ( C ) implant with a 2.8 mm turned neck were r and omly assigned . All implants were placed transmucosally to the same sink depth of approximately 1.8 mm . Peri-apical radiographs were obtained using the paralleling technique and digitized . Two investigators blinded to the implant type-evaluated soft and hard tissue conditions at baseline , 6 months and 1 year after loading . RESULTS the mean crestal bone levels and soft tissue parameters were not significantly different between T and C implants at all time points . However , T implants displayed significantly less crestal bone loss than C implants after 1 year . Moreover , a frequency analysis revealed a higher percentage ( 50 % ) of T implants with crestal bone levels 1 - 2 mm below the implant shoulder compared with C implants ( 5.6 % ) 1 year after loading . CONCLUSION implants with a reduced height turned neck of 1.8 mm may , indeed , lower the crestal bone resorption and hence , may maintain higher crestal bone levels than do implants with a 2.8 mm turned neck , when sunk to the same depth . Moreover , several factors other than the vertical positioning of the moderately rough SLA surface may influence crestal bone levels after 1 year of function OBJECTIVE This prospect i ve r and omized match-paired controlled trial aim ed to evaluate the impact of implant platform diameter on marginal bone level around implants restored according to the platform switching ( PS ) concept . MATERIAL AND METHODS A total of 24 implants were examined in 12 patients . All patients received two adjacent implants inserted at the crestal level : 4.3 mm ( control group ) and 4.8 mm ( test group ) in diameter . Mesio-distal implant position was r and omly performed . According to the PS concept , for restoration , a 3.8 and 4.3 mm diameter abutment was used , respectively in the control and test groups , result ing , in both groups , with 0.25 mm of implant/abutment mismatching . Implant restorations were splinted . Eighteen months after final restoration , periapical st and ardized digital radiographs were taken to evaluate marginal bone level alterations after loading . The Wilcoxon Signed-Rank Test was selected to identify differences between groups . RESULTS At the last follow-up , control implants exhibited a mean bone loss value of 1.10 mm ( SD : 0.47 mm ) ; the test group showed a mean value of 1.09 mm ( SD : 0.08 mm ) . No statistically significant differences were found between test and control groups . CONCLUSIONS Within the limits of this study , the present results suggest that bone resorption is mostly related to biologic ( biologic width re-establishment ) rather than to biomechanical factors ( implant platform diameter ) . Furthermore long-term studies with a wider sample size are needed to confirm the platform diameter influence on hard tissue response around implants restored according to the PS concept OBJECTIVE To evaluate how bone-level implants  maintain crestal bone stability after thickening of thin mucosal tissues with allogenic membrane . MATERIAL S AND METHODS Ninety-seven bone-level implants of 4.1 mm diameter ( Institute Straumann AG , Switzerl and ) were evaluated in 97 patients ( 28 men and 69 women , mean age 47.3 ± 1.2 years ) . According to vertical gingival thickness , patients were assigned into test T1 ( thin , 2 mm or less , n = 33 ) , test T2 ( thin thickened with allogenic membrane , n = 32 ) and control C groups ( thick , more than 2 mm , n = 32 ) . Implants were placed in posterior m and ible in one-stage approach and after integration were restored with single screw-retained metal-ceramic restorations . Radiographic examination was performed after implant placement , 2 months after healing , after prosthetic restoration and after 1-year follow-up . Crestal bone loss was calculated mesially and distally . Mann-Whitney U-test was applied and significance was set to 0.05 . RESULTS After 2 months , implants in group T1 had 0.75 ± 0.11 mm bone loss mesially and 0.73 ± 0.10 mm distally . Implants in group T2 had 0.16 ± 0.06 mm mesially and 0.20 ± 0.06 mm distally . C group implants lost 0.17 ± 0.05 mm mesially and 0.18 ± 0.03 mm distally . Differences between T1/T2 , and T1/C were statistically significant ( P = 0.000 ) both mesially and distally , while between T2 and C was not significant mesially ( P = 0.861 ) and distally ( P = 0.827 ) . After 1-year follow-up implants in group T1 had 1.22 ± 0.08 mm bone loss 
    Output:
    
Metaregression of the selected studies failed to demonstrate an association among MBL and confounding factors .
The current study demonstrates that implants placed with an initially thicker peri-implant soft tissue have less radiographic MBL in the short term