***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 The purpose of this prospect i ve clinical study was to evaluate peri-implant soft-tissue conditions and esthetic fulfillment during a 3-year follow-up period following prosthetic rehabilitation . MATERIAL AND METHODS As part of a prospect i ve multi-center study , 152 ITI dental implants were placed in 80 patients in the maxillary anterior region . Fifty-nine crowns ( 38.82 % ) were cement retained , while 93 ( 61.18 % ) crowns were screw retained . At loading and 3 , 6 , 12 and 36 months post-loading , modified plaque index ( MPI ) , sulcus bleeding index ( SBI ) , keratinized mucosa ( KM ) , gingival level ( GL ) , and esthetic fulfillment were recorded . RESULTS All patients completed the study and no complications were reported . While statistically not significant at all time points , cement-retained crowns seemed to present a worsening trend in MPI and SBI scores . Interestingly , screw-retained crowns seemed to present an opposite picture , their MPI and SBI scores improved over time . While plaque accumulation , prophylaxis and depth of crown margin significantly affected levels of sulcus bleeding , prophylaxis alone played a key role in reducing plaque accumulation . No soft tissue recession was observed in either cement- or screw-retained crowns up to 3 years post-loading . Esthetic fulfillment survey revealed that patients did not have a preference for crown types ; however , dentists favored cement-retained over screw-retained crowns . CONCLUSIONS Peri-implant soft tissues responded more favorably to screw-retained crowns when compared with cement-retained crowns . However , no soft-tissue recession was observed in either type of crowns . Cement-retained crowns were preferred by dentists , while patients were equally satisfied with either type of crowns they received PROBLEM The Ankylos endosseous dental implant is a new implant design that will be available in the United States in early 2004 . It features an internal tapered abutment connection , a smooth polished collar without threads at the coronal part of the implant body , and a roughened surface with variable threads on the body of the implant fixture . A precise , tapered , conical abutment connection eliminates the microgap often found in 2-stage implant systems . This microgap may allow the accumulation of food debris and bacteria , as well as micromovement between the parts during clinical function , both of which can lead to a localized inflammation and crestal bone loss . PURPOSE The purpose of this section of the study was to assess any crestal bone loss associated with this new implant . METHOD The clinical performance of this new implant design was studied under well-controlled clinical conditions . Over 1500 implants were placed and restored . The vertical crestal bone loss was measured " directly " between the time of implant placement and uncovering , using a periodontal probe . Serial dental radiographs were taken between loading , and the 12- , 24- , and 36-month follow-up visits to determine " indirect " crestal bone loss within a specific period . RESULTS Bone loss varied among the participating centers from less than 0.5 mm to 2.0 mm . The largest amount of bone loss occurred between the time of placement and uncovering . Following loading , the mean bone loss for all implants for a period of 3 years was about 0.2 mm/y . CONCLUSIONS The extent of the crestal bone loss after loading was minimal for patients regardless of age , gender , prosthetic applications , bone density , and remote or crestal incisions , as well as for smokers or nonsmokers .  Bone loss per year is well within the guidelines of 0.2 mm/y proposed by others OBJECTIVE To evaluate marginal bone loss over 3 years around immediate microthreaded implants placed in the maxillary anterior/esthetic zone and immediately restored with single crowns . MATERIAL AND METHODS Seventy-one implants  ( with microthreads up to the platform -- rough surface body and neck , internal connection and platform switching ) were placed in fresh extraction sockets in the maxillary arches of 30 men and 23 women ( mean age 37.85 ± 7.09 years , range 27 - 60 ) . All subjects had at least 3 mm of soft tissue to allow the establishment of adequate biologic width and to reduce bone resorption . Each patient received a provisional restoration immediately after implant placement with slight occlusal contact . Mesial and distal bone height was evaluated using digital radiography on the day following implant placement ( baseline ) and after 1 , 2 , and 3 years . Primary stability was measured with resonance frequency analysis . RESULTS No implants failed , result ing in a cumulative survival rate of 100 % after 3 years . Marginal bone loss from implant collar to bone crest measured at baseline ( peri-implant bone defect at the fresh extraction socket ) and after 3 years was 0.86 mm ± 0.29 mm . Mesial and distal site crestal bone loss ranged from 3.42 mm ± 1.2 mm at baseline to 3.51 mm ± 1.5 mm after 3 years ( P = 0.063 ) and from 3.38 mm ± 0.9 mm at baseline to 3.49 mm ± 0.9 mm after 3 years , respectively ( P = 0.086 ) . CONCLUSIONS This prospect i ve study found minimal marginal bone loss and a 100 % implant survival rate over the 3-year follow-up for microthreaded immediate implants subjected to immediate non-occlusal loading OBJECTIVES This r and omised , controlled multicentre trial aim ed at comparing two versions of a variable-thread dental implant design to a st and ard tapered dental implant design in cases of immediate functional loading for 36 months after loading . MATERIAL S AND METHODS 177 patients ( 325 implants ) were included at 12 study centres and r and omly allocated into one of three treatment groups : NAI ( variable-thread design , NobelActive internal connection ) , NAE ( variable-thread design , NobelActive external connection ) and , as control , NR ( st and ard tapered design , NobelReplace tapered groovy ) . Inclusion criteria concerned healed bony implant sites and feasibility for immediate loading . Clinical and radiographic examinations were performed at implant placement and after 3 , 6 , 12 , 24 and 36 months . The outcome measures were marginal bone remodelling ( primary outcome ) , implant survival and success , papilla score , plaque accumulation , and bleeding on probing . RESULTS 127 patients ( NAI : 45 , NAE : 41 , NR : 41 ) were followed-up and evaluated after 36 months . No significant differences in cumulative survival rates were seen for the groups ( NAI : 95.7 % ; NAE : 96.3 % ; NR : 96.6 % ) . In all groups , bone remodelling occurred during the first 3 months , with stable or even increasing bone levels after the initial remodelling period . The bone remodelling from insertion to 36 months for the NAI group ( -0.89 ± 1.65 mm ) was comparable ( P = 0.98 ) to that of the NR group ( -0.85 ± 1.32 mm ) . The NAE group showed comparable bone remodelling during the first year , with an increase in following years result ing in significantly less overall bone loss ( -0.16 ± 1.06 mm ) ( P = 0.041 ) . Overall improvement in papilla size was observed in all treatment groups . CONCLUSIONS Over 36 months , the results show stable or improving bone levels for all treatment groups after the initial bone remodelling seen during the first 3 months after placement . The variable- thread implants showed results comparable to those of st and ard tapered implants in cases of immediate function , and therefore can be considered as a treatment option for immediate loading PURPOSE The present study was design ed to compare the long-term outcome and complications of cemented versus screw-retained implant restorations in partially edentulous patients . MATERIAL S AND METHODS Consecutive patients with bilateral partial posterior edentulism comprised the study group . Implants were placed , and cemented or screw-retained restorations were r and omly assigned to the patients in a split-mouth design . Follow-up ( up to 15 years ) examinations were performed every 6 months in the first year and every 12 months in subsequent years . The following parameters were evaluated and recorded at each recall appointment : ceramic fracture , abutment screw loosening , metal frame fracture , Gingival Index , and marginal bone loss . RESULTS Thirty-eight patients were treated with 221 implants to support partial prostheses . No implants during the follow-up period ( mean follow-up , 66 ± 47 months for screw-retained restorations [ range , 18 to 180 months ] and 61 ± 40 months for cemented restorations [ range , 18 to 159 months ] ) . Ceramic fracture occurred significantly more frequently ( P < .001 ) in screw-retained ( 38 % ± 0.3 % ) than in cemented ( 4 % ± 0.1 % ) restorations . Abutment screw loosening occurred statistically significantly more often ( P = .001 ) in screw-retained ( 32 % ± 0.3 % ) than in cement-retained ( 9 % ± 0.2 % ) restorations . There were no metal frame fractures in either type of restoration . The mean Gingival Index scores were statistically significantly higher ( P < .001 ) for screw-retained ( 0.48 ± 0.5 ) than for cemented ( 0.09 ± 0.3 ) restorations . The mean marginal bone loss was statistically significantly higher ( P < .001 ) for screw-retained ( 1.4 ± 0.6 mm ) than for cemented ( 0.69 ± 0.5 mm ) restorations . CONCLUSION The long-term outcome of cemented implant-supported restorations was superior to that of screw-retained restorations , both clinical ly and biologically PURPOSE To compare the clinical and radiological outcomes of two implant design s with different prosthetic interfaces and neck configurations . MATERIAL S AND METHODS Thirty-four partially edentate patients r and omly received at least one NobelActive implant ( Nobel Biocare  , Göteborg , Sweden ) with back-tapered collar , internal conical connection and platform shifting design , and one NobelSpeedy implant ( Nobel Biocare ) with external hexagon and flat-to-flat implant-abutment interface according to a split-mouth design . Follow-up continued to 3 years post-loading . The primary outcome measures were the success rates of the implants and prostheses , and the occurrence of any surgical and prosthetic complications during the entire follow-up . Secondary outcome measures were : horizontal and vertical peri-implant marginal bone level ( MBL ) changes , resonance frequency analysis values at implant placement and loading ( 4 months ) , sulcus bleeding index ( SBI ) and plaque score ( PS ) . RESULTS No drop-out occurred . No implants and prostheses failures were observed to the 3-year follow-up . MBL changes were statistically significant different with better results for the NobelActive implants for both horizontal and vertical measurements ( P = 0.000 ) . After 3 years post-loading , the NobelActive implants underwent a mean vertical bone resorption of 0.66 mm , compared with 1.25 mm for the NobelSpeedy Groovy implants ( P = 0.000 ) ; the mean horizontal bone resorption was 0.19 mm for the NobelActive implants and 0.60 mm for the NobelSpeedy Groovy implants ( P = 0.000 ) . A high ISQ value was found for both implants , and no statistically significant difference was found for ISQ mean values between interventions ( P = 0.941 at baseline ; P = 0.454 at implantabutment connection ; P = 0.120 at prosthesis delivery ) . All implants showed good periodontal health at the 3-year-in-function visit , with no significant differences between groups . CONCLUSION The results of this research suggest that in well-maintained patients , the MBL changes could be affected by the different implant design . After 4 months of unloaded healing , as well as after 3 years in function , both implants provided good results , however vertical and horizontal bone loss had statistically significant differences between the two groups ( difference of 0.58 ± 0.10 mm for the vertical MBL , and 0.4 ± 0.05 mm for the horizontal MBL ) , with lower values in the Nobel Active implants , compared to the NobelSpeedy Groovy implants 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 
    Output:
    
Osseointegrated dental implants with internal connections exhibited lower marginal bone loss than implants with external connections .