***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: This study aims to analyze the clinical performance of two loading concepts on second-generation palatal implants  ( Orthosystem , Straumann , Basel , Switzerl and ) in a prospect i ve multicenter r and omized controlled clinical trial . At the time of this interim analysis , 41 patients have been r and omized on a 1:1 basis to one of two treatment groups . Group 1 underwent conventional loading of palatal implants after a healing period of 12 weeks ( gold st and ard ) while group 2 underwent immediate implant loading within 1 week after implant insertion . We report initial results at 6 months after functional loading . The primary outcome parameter was implant success ( no implant mobility , no implant loss ) . The implants in both groups were initially stable at the time of insertion , and all were eligible for r and omization . Twenty-two patients ( group 1 ) were subjected to conventional implant loading after 12 weeks while 19 patients ( group 2 ) received immediate functional loading within the first week after insertion . Direct ( e.g. distal jet appliances ) as well as indirect forms of anchorage ( conventional or modified transpalatal arch ) were used . The magnitude of orthodontic forces ranged between 1 and 4 N for the immediate loading group and between 1 and 5 N for the conventional loading group . One implant in group 1 was lost during the healing phase . One dropout was registered in group 2 . Thirty-nine implants were functionally loaded for over 6 months now . These preliminary data provide first evidence of the fact that immediate loading of palatal implants yields equivalent success rates as conventional loading to 4 N after 6 months The purpose of this study was to evaluate  crestal bone loss around 282 two-piece implants with straight ( n = 193 ) and platform-switched ( n = 89 ) abutment connections after placement at various crestal levels .  Implants were assigned into two groups according to straight and platform-switched abutment connections . Each group was further subdivided into three groups depending on the location ( supracrestal , crestal , or subcrestal ) of the implant cervical platform . Linear measurements of bone resorption were made from the implant 's platform to the first point of bone-to-implant contact at the time of implant placement and 2 years postrestoration . Data were statistically analyzed . Statistically significant differences were found between subgroups in both straight and platform-switched categories . The only nonstatistically significant difference ( P = .341 ) arose when comparing the supra- and subcrestal locations in the straight abutment connection group . The platform-switched group exhibited significantly less bone loss ( P = .046 ) only in subcrestal locations . The platform-switched concept was not beneficial during the overall comparison , but it was for the subcrestal location of the abutment connection . Crestal placement of the implant-abutment connection result ed in higher marginal bone resorption in both straight and platform-switched abutments BACKGROUND There is limited information regarding the effect of grafting of the osteotomy after subcrestal implant placement . The primary aim of this study is to retrospectively evaluate the effect of bone grafting of the defect between the bone crest and the coronal aspect of implants with reduced abutment diameter placed non-submerged and at subcrestal positions . METHODS Records of 50 consecutive patients treated with subcrestally placed dental implants grafted with a xenograft ( Group A ) and 50 consecutive patients with subcrestally placed dental implants without any grafting material ( Group B ) were review ed . For each implant , the radiographs after placement were compared to images from the last follow-up visit and evaluated regarding the following : 1 ) degree of subcrestal positioning of the implant , 2 ) changes of marginal hard-tissue height over time , and 3 ) whether marginal hard-tissue could be detected on the implant platform at the follow-up visit . RESULTS The mean marginal loss of hard tissues was 0.11 ± 0.30 mm for Group A and 0.08 ± 0.22 mm for Group B. Sixty-nine percent of the implants in Group A and 77 % of the implants in Group B demonstrated hard tissue on the implant platform . There were no statistically significant differences between the groups regarding marginal peri-implant hard-tissue loss . CONCLUSION The present study fails to demonstrate that grafting of the remaining osseous wound defect between the bone crest and the coronal aspect of the implant has a positive effect on marginal peri-implant hard-tissue changes Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more BACKGROUND Dental implants with moderately rough surfaces are commonly used in the treatment of edentulous patients . However , long-term data on survival rates and marginal bone conditions are lacking . PURPOSE This prospect i ve study evaluated the cumulative survival rate of the TiOblast implant ( Astra Tech AB , Mölndal , Sweden ) after 10 years of prosthetic loading . MATERIAL S AND METHODS A total of 199 TiOblast implants were placed in 36 consecutive edentulous patients ( 23 males and 13 females ) . All patients were treated at one clinic and by the same team . The patients were edentulous in either the maxilla ( n = 16 ) or the m and ible ( n = 20 ) . The average age of the patients at the start of the trial was 64 years ( range , 59 - 82 years ) . Of the 199 implants inserted 108 were in the m and ible and 91 were in the maxilla . Clinical evaluations were undertaken after completion of the prosthetic superstructure ( baseline ) and after 6 months , 1 year , 3 years , 5 years , 7 years , and 10 years . Mean marginal bone level was evaluated for the first 100 placed implants for up to 7 years . RESULTS Six implants failed during the study ( 3 in the m and ible and 3 in the maxilla ) . All failures occurred within the first year , giving a cumulative survival rate of 96.9 % ( 96.6 % in the maxilla and 97.2 % in the m and ible ) after 10 years of follow-up . The survival rate for the superstructures was 100 % . The mean marginal bone level in the measured sample was 0.2 mm ( st and ard deviation [ SD ] , 0.31 ) below the reference point at baseline , 0.28 mm ( SD , 0.20 ) and 1.27 mm ( SD , 1.15 ) below the same point 7 years later ( mean , 0.15 mm per year ) . CONCLUSION This study showed that titanium dioxide-blasted implants offer predictable long-term results as supports for fixed prostheses in both the maxilla and m and ible PURPOSE The purpose of this clinical trial was to evaluate whether the crestal bone height around dental implants  could be influenced by the use of a platform-switching protocol . MATERIAL S AND METHODS All implants placed in the year 2006 in healed bone without any need for ridge augmentation were included in this study . The following groups were created : ( 1 ) wide-diameter implants were placed subcrestally and regular-diameter cover screws were connected ; ( 2 ) regular-diameter implants were placed at the crest and regular-diameter cover screws were connected . St and ardized radiographs were obtained after insertion of the definitive prosthesis and after 1 year . Calibrated measurements were conducted initiating from the mesial and distal bone peaks to the implant-abutment junction . The average value of the mean medial and mean distal values was calculated and analyzed with an unpaired two-tailed t test . P values < .05 were regarded as statistically significant . RESULTS In all , 89 dental implants in 36 patients were evaluated . The implants with a platform-switched configuration ( n = 75 ) exhibited statistically significantly less bone loss at time of insertion of the definitive prosthesis ( 0.30 + /- 0.07 mm versus 0.68 + /- 0.17 mm ; P < .05 ) and at 1 year ( 0.39 + /- 0.07 mm versus 1.00 + /- 0.22 mm , P < .01 ) when compared to the nonplatform-switched implants ( n = 14 ) . CONCLUSION Platform-switched implants seem to limit crestal bone remodeling Background To assess the influence of the crestal or subcrestal placement of implants upon peri-implant bone loss over 12 months of follow-up . Material and Methods Twenty-six patients with a single hopeless tooth were recruited in the Oral Surgery Unit ( Valencia University , Valencia , Spain ) . The patients were r and omized into two treatment groups : group A ( implants placed at crestal level ) or group B ( implants placed at subcrestal level ) . Control visits were conducted by a trained clinician at the time of implant placement and 12 months after loading . A previously established st and ard protocol was used to compile general data on all patients ( sex and age , implant length and diameter , and brushing frequency ) . Implant success rate , peri-implant bone loss and the treatment of the exposed implant surface were studied . The level of statistical significance was defined as 5 % ( α=0.05 ) . Results Twenty-three patients ( 8 males and 15 females , mean age 49.8±11.6 years , range 28 - 75 years ) were included in the final data analyses , while three were excluded . All the included subjects were nonsmokers with a brushing frequency of up to twice a day in 85.7 % of the cases . The 23 implants comprised 10 crestal implants and 13 subcrestal implants . After implant placement , the mean bone position with respect to the implant platform in group A was 0.0 mm versus 2.16±0.88 mm in group B. After 12 months of follow-up , the mean bone positions were -0.06±1.11 mm and 0.95±1.50 mm , respectively - this representing a bone loss of 0.06±1.11 mm in the case of the crestal implants and of 1.22±1.06 mm in the case of the subcrestal implants ( p=0.014 ) . Four crestal implants and 5 subcrestal implants  presented peri-implant bone levels below the platform , leaving a mean exposed treated surface of 1.13 mm and 0.57 mm , respectively . The implant osseointegration success rate at 12 months was 100 % in both groups . Conclusions Within the limitations of this study , bone loss was found to be greater in the case of the subcrestal implants , though from the clinical perspective these implants presented bone levels above the implant platform after 12 months of follow-up . Key words : Immediate implants , tooth extraction , dental implants , single-tooth , crestal bone , placement level BACKGROUND It has been reported in many articles that marginal bone resorptions are prevented by platform-switching design . However , what occurs when these implants are placed in the apical position is not completely known . PURPOSE This report describes a r and omized controlled clinical trial study that aims to test the hypothesis that less resorption will occur when platform-switching implants are placed 1 mm below bone level . MATERIAL S AND METHODS A total of 56 r and omly selected implants were inserted bilaterally , either 1 mm below bone level ( test group , 28 implants ) or at bone level ( control group , 28 implants ) of the patients ' posterior regions .  Marginal bone resorptions were examined through periapical radiographies taken with the parallel technique at the time of crown cementation and the third , sixth , 12th , and 36th months after prosthetic loading . The modified plaque index , gingival index , bleeding on probing , and probing depths were used for follow-up periodontal care of the implants . RESULTS After 3 years , the mean radiographic vertical bone loss in the control group was significantly lower than in the test group ( 0.56 ± 0.35 mm and 1.21 ± 1.05 mm , respectively ) ( p < .01 ) . In terms of periodontal indexes , there were no statistically significant differences between the two groups ( p > .05 ) . No peri-implantitis or peri-implant mucositis was observed around the test or control implants . CONCLUSIONS More marginal bone resorptions occurred after the third year of loading in implants placed 1 mm below bone level . However , the resorptions did not reach the implants thread . In the control group , the first bone implant contact was placed under the level of the first threads . Therefore , the present r and omized clinical trial confirmed the hypothesis that placing platform-switching implants 1 mm below bone level reduced marginal bone loss . It can be noted that to reduce resorption , platform-switching implants should be placed below bone level OBJECTIVES To assess the impact of microgrooved abutments and the insertion depth on crestal bone changes at titanium implants with platform switch . MATERIAL S AND METHODS A total of n = 3  titanium implants  ( conical abutment connection ) were inserted in each hemim and ible of n = 6 foxhounds with the implant shoulder ( IS ) located at either epicrestal , supracrestal ( + 1 mm ) , or subcrestal ( -1 mm ) positions and r and omly ( split-mouth design ) connected with machined or partially microgrooved healing abutments  . At 20 weeks , tissue biopsies were processed for histological ( 
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Conclusion This systematic review suggests that PS implants placed in a subcrestal position have less MBL changes when compared with implants placed equicrestally .
Furthermore , the location of the microgap seems to have an influence on the dimensions of peri-implant soft tissues .
Clinical relevance When compared with PS placed in an equicrestal position , subcrestal implant positioning demonstrated less peri-implant bone remodeling