***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 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 The purpose of this study is to assess the influence of the placement level of implants with a laser-microtextured collar design on the outcomes of crestal bone and soft tissue levels . In addition , we assessed the vertical and horizontal defect fill and identified factors that influenced clinical outcomes of immediate implant placement . METHODS Twenty-four patients , each with a hopeless tooth ( anterior or premolar region ) , were recruited to receive dental implants .  Patients were r and omly assigned to have the implant placed at the palatal crest or 1 mm subcrestally . Clinical parameters including the keratinized gingival ( KG ) width , KG thickness , horizontal defect depth ( HDD ) , facial and interproximal marginal bone levels ( MBLs ) , facial threads exposed , tissue-implant horizontal distance , gingival index ( GI ) , and plaque index ( PI ) were assessed at baseline and 4 months after surgery . In addition , soft tissue profile measurements including the papilla index , papilla height ( PH ) , and gingival level ( GL ) were assessed after crown placement at 6 and 12 months post-surgery . RESULTS The overall 4-month implant success rate was 95.8 % ( one implant failed ) . A total of 20 of 24 patients completed the study . At baseline , there were no significant differences between crestal and subcrestal groups in all clinical parameters except for the facial MBL ( P = 0.035 ) . At 4 months , the subcrestal group had significantly more tissue thickness gain ( keratinized tissue ) than the crestal group compared to baseline . Other clinical parameters ( papilla index , PH , GL , PI , and GI ) showed no significant differences between groups at any time . A facial plate thickness ≤1.5 mm and HDD ≥2 mm were strongly correlated with the facial marginal bone loss . A facial plate thickness ≤2 mm and HDD ≥3 were strongly correlated with horizontal dimensional changes . CONCLUSIONS The use of immediate implants was a predictable surgical approach ( 96 % survival rate ) , and the level of placement did not influence horizontal and vertical bone and soft tissue changes . This study suggests that a thick facial plate , small gaps , and premolar sites were more favorable for successful implant clinical outcomes in immediate implant placement The medium-long term success of osseointegrated dental implants  is evaluated on the basis of the degree of osseointegration over time , assessed by radiographic or instrumental analysis ( ISQ ) . Over the years , the question has always been which surgical technique can provide a better performance in the medium-long term and , thanks to literature studies , it has been evidence d that there are no differences between " one stage " and " two stage " interventions . The purpose of this study is to evaluate clinical and radiographic parameters , referring to interventions for the insertion of dental implants characterized by a new kind of implant surface ( Synthegra ® GEASS , Udine ) . The prospect i ve study , not r and omized and controlled , referred to the insertion of  18 implants on 9 patients with mono or bilateral edentulism , with measurements at 1 , 3 , 6 and 12 months and an overall follow-up at 3 years , in order to evaluate the different degree of crestal bone resorption using the submerged and transmucosal surgical technique . The results of our study show that there are no differences in the resorption of the two surgical techniques , with an average bone resorption of 2,05±0,16 mm , comparable with values reported in literature 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 ( primary outcome : net bone loss - NET ) analyses . RESULTS Subcrestal positioning of IS tended to be associated with higher mean NET values ( mm ) at both machined ( subcrestal [ -0.72 ± 0.32 ] > epicrestal [ -0.34 ± 0.21 ] > supracrestal [ + 0.20 ± 0.64 ] ) and microgrooved ( subcrestal [ -0.48 ± 0.25 ] > epicrestal [ -0.13 ± 0.54 ] > supracrestal [ + 0.33 ± 0.58 ] ) abutments . However , these differences failed to reach statistical significance . CONCLUSIONS The insertion depth may have a direct influence on crestal bone-level changes at both types of abutments investigated 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 PURPOSE Submerged and nonsubmerged ITI solid-screw titanium implants were followed retrospectively from 1989 to 1993 and prospect ively from 1994 on to analyze long-term prognosis in partially and fully edentulous patients . MATERIAL AND METHODS A total of 468 implants were consecutively inserted in 191 patients from 1989 to 1998 . Two hundred twenty-eight successfully integrated fixed-restoration implants and 238 with removable restorations were restored following a healing period of 4 to 6 months ( 9 months in sinus floor elevation sites ) . From 1994 on all implants inserted were documented annually up to 9 years . During examination the clinical status of the implants was analyzed and evaluated according to predefined criteria of success and this allowed the calculation of 10-year cumulative survival and success rates for 468 implants . RESULTS Two implants ( 0.43 % ) did not successfully integrate during the healing period , and 8 implants ( 1.7 % ) were classified as failures during follow-up ( 1 late failure under load , 7 with a progressive bone loss from 1 to 3 threads ) . Including 68 implants in subjects who dropped out ( with a dropout rate of 14.4 % ) , the 10-year cumulative survival and success rates were 99.2 % and 96.4 % , respectively . DISCUSSION Over the course of this long-term study , osseointegrated implants , once used as a last possible solution , became nearly st and ard in cases of single-tooth implants because of the high rate of long-term success . Life table analysis not only determines whether an implant is functioning , it also makes a statement about its clinical status according to strict success criteria . CONCLUSION The study demonstrated that ITI solid-screw titanium implants achieved success rates above 95 % in a clinical center for an observation period of up to 10 years BACKGROUND Today , implants are placed using both non-submerged and submerged approaches , and in 1- and 2-piece configurations . Previous work has demonstrated that peri-implant crestal bone reactions differ radiographically under such conditions and are dependent on a rough/smooth implant border in 1-piece implants and on the location of the interface ( microgap ) between the implant and abutment/restoration in 2-piece configurations . The purpose of this investigation was to examine histometrically crestal bone changes around unloaded non-submerged and submerged 1- and 2-piece titanium implants in a side-by-side comparison . METHODS A total of 59 titanium implants were r and omly placed in edentulous m and ibular areas of 5 foxhounds , forming 6 different implant subgroups ( types A-F ) . In general , all implants had a relatively smooth , machined coronal portion as well as a rough , s and blasted and acid-etched ( SLA ) apical portion . Implant types A-C were placed in a non-submerged approach , while types D-F were inserted in a submerged fashion . Type A and B implants were 1-piece implants with the rough/smooth border ( r/s ) at the alveolar crest ( type A ) or 1.0 mm below ( type B ) . Type C implants had an abutment placed at the time of surgery with the interface located at the bone crest level . In the submerged group , types D-F , the interface was located either at the bone crest level ( type D ) , 1 mm above ( type E ) , or 1 mm below ( type F ) . Three months after implant placement , abutment connection was performed in the submerged implant groups . At 6 months , all animals were sacrificed . Non-decalcified histology was analyzed by evaluating peri-implant crestal bone levels . RESULTS For types A and B 
    Output:
    
No significant difference in CBL was found around submerged and nonsubmerged dental implants