***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: PURPOSE This multicenter investigation is an interim 3-year survival report of a 5-year prospect i ve study using Brånemark osseointegrated implants in partially edentulous patients . MATERIAL S AND METHODS Previously defined patient characteristics and clinical parameters were related to implant survival using lifetable analysis . RESULTS Three years after prosthesis insertion , 460 implants placed in 139 patients remained in the study .  Cumulative success rates for maxillary implants ( 92.5 % ) were less than for m and ibular implants ( 94.8 % ) , with an overall cumulative success rate of 93.9 % . CONCLUSION Failures were associated with poor bone quality , smaller implant sizes , and a higher plaque index , and were more likely to occur before loading . A 4 % incidence of residual long-term inferior alveolar nerve paresthesia was higher than previously reported PURPOSE Bone resorption following tooth loss often limits the quantity of bone available for implant placement . The purpose of the present study was to evaluate the clinical outcome of 10-mm or shorter machined-surface implants when used exclusively in the treatment of various forms of edentulism . MATERIAL S AND METHODS Two hundred sixty-nine screw-type Brånemark System implants ( Nobel Biocare ) , 10 mm or shorter , were placed in 111 consecutively treated patients . Of the total , 88.8 % were placed in the m and ible and 11.2 % were placed in the maxilla ; 95.2 % were used to treat partially edentulous situations , including single-tooth losses , of which 96.6 % were in the premolar and molar regions . The patients were followed for periods of 12 to 92 months . RESULTS Of the 269 placed implants , 12 were lost . The overall survival rate was 95.5 % . Bone quality 2 and 3 ( Lekholm-Zarb classification of 1985 ) was found in 88.8 % of the treated sites . There was no statistical difference in the survival rate of the 10-mm implants when compared to the shorter series ( P > .05 ) or between the various implant diameters . The mean marginal bone loss was 0.71 + /- 0.65 mm . DISCUSSION The failure rate of 4.5 % compares favorably with that of implants of different shape , surface characteristics , and length . Bone quality appeared to be the critical factor in implant survival , rather than bone quantity , in this patient series . CONCLUSIONS This study supports the survival of short , machined-surface implants when used for the treatment of partial edentulism in bone of good quality While considerable data have been published on the use of the  osseointegration technique  in the anterior region of the edentulous mouth , there remains scant information on its success in the posterior areas of either the maxillae or m and ible . This prospect i ve study was begun in the mid-1980s to test the effectiveness of this technique in the treatment of partially edentulous posterior areas of the maxillae and m and ible , and in situations where the implant-supported prosthesis carries a significant portion of the total occlusal load . One hundred five implants were placed into 46 edentulous areas in 35 patients . After periods of loaded service ranging from 2.6 to 7.4 years ( mean 5.2 years ) , of the 41 implants placed in maxillae , 40 ( 97.6 % ) remain in function , and of the 64 placed in m and ibles , 59 ( 92.2 % ) remain in function . The overall implant survival rate of 94.3 % suggests that partially edentulous areas in the posterior zones of either arch can be treated prosthodontically using osseointegrated implants with predictable success 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 Objective To evaluate the clinical effectiveness , common complications and maintenance associated with hydroxylapatite ( HA ) coated cylindrical implants when used to support single crowns . Design A prospect i ve medium term clinical study of the Calcitek HA-coated implant . Setting Implant placement , crown fabrication and follow-up procedures were carried out at the Leeds Dental Institute , between 1990 and 1998.Subjects and method 26 patients ( 33 implants ) participated in the trial . They were referred from general dental practitioners because of their suitability for single tooth implant placement . Main outcome measures The implants were assessed using recognised clinical review procedures eg radiographs and soft tissue assessment s. Results At exposure there was 100 % implant integration . The cumulative survival rate over 4 years was 100 % . In five implants there was cervical bone loss of more than 4 mm and these were classified as failing . This gave an overall cumulative success rate of 58 % by year 4 . Conclusion The Calcitek HA-coated single tooth implant shows exceptionally high initial integration however , the longer term results suggest that the cervical bone level adjacent to the implant failed to establish a steady state . Doubts remain regarding the long-term prognosis of these cylindrical HA-coated implants A 3-year multicenter study on 63 maxillary and 10 m and ibular fixed prostheses in 71 patients is reported . Angulated abutments or a combination of angulated and st and ard abutments were used to support prostheses ; all components were from the Brånemark System . Of 425 implants initially placed , 4 were lost before abutment connection . Of the remaining 421 implants , 209 angulated ( test ) abutments and 212 st and ard ( control ) abutments were placed to support fixed prostheses . The prosthesis success rates were 96.8 % for maxillae and 100 % for m and ibles . A total of 5.3 % of the loaded test implants and 7.5 % of the loaded control implants failed . The survival rates after 3 years were 91.3 % for maxillary control implants , 94.8 % for maxillary test implants , 97.4 % for m and ibular control implants , and 94.1 % for m and ibular test implants . The findings in this study pointed out that angulated abutments will not necessarily promote peri-implant mucosal problems . The study indicated that angulated abutments on Brånemark System implants have exhibited good preliminary results and should be comparable to the st and ard abutment as a predictable modality in prosthetic rehabilitation This report outlines the experimental , surgical , and prosthodontic protocol s for a prospect i ve clinical trial using the Endopore dental implant to replace single maxillary teeth . Twenty patients ( 10 male , 10 female ) ranging in age from 30 to 60 years each received one implant  ( mean length 10.1 mm ) , which , after an initial healing period of 4 months , was restored with a single crown . Records collected included radiographs , Periotest mobility measurements , supragingival Plaque Index , and an assessment of peri-implant soft tissue health using pocket probing depths , sulcular bleeding following probing , and probing attachment levels . Radiographs were exposed at predetermined intervals following crown placement ( 1 and 6 months , and then yearly ) in a st and ardized procedure using a specialized filmholder that attaches to each implant after removal of the crown . At the time of this preliminary report , all of the 20 implants placed had been uncovered and were in function ; 16 of the implants had been in function for 6 months or more , 14 had passed 1 year of function , and 3 had passed the 2-year function point . There have been no failures to date STATEMENT OF PROBLEM Treatment of tooth loss in the anterior maxilla can involve difficult functional , esthetic , and psychologic problems , especially in young patients with otherwise good dentition . PURPOSE The purpose of this study was to provide a preliminary comparative evaluation of two implants ( ITI and Astra ) in single-tooth restorations . MATERIAL AND METHODS This prospect i ve study of 102 single-tooth replacements with 56 ITI and 46 Astra dental implants was performed in 82 patients at the Finnish Student Health Service Foundation . One Astra implant was lost before loading . The overall survival rate of the implants was 97.8 % for Astra implants and 100 % for the ITI system . After the initial healing period of at least 6 months , the remaining 101 implants ( 56 ITI , 45 Astra ) were free of periimplant infection and revealed no detectable mobility . Radiographs did not reveal signs of periimplant radiolucencies . All 101 implants received single-tooth crowns . RESULTS Periimplant parameters and acceptable implant function were examined and demonstrated satisfactory results with preestablished clinical parameters and radiographs at 1 year . During the observation time the mean marginal bone loss was 0.13 mm with Astra implants and 0.11 mm with ITI implants . Subjectively all patients were satisfied with their single-tooth restorations supported by either ITI or Astra dental implants . CONCLUSION The favorable results of this short-term study support the application of the two implant systems for single-tooth restorations , especially in the anterior region of the maxilla Osseointegrated implants as anchors for various prosthetic reconstructions have become a predictable treatment alternative . It was expected that implants required submucosal placement during the healing period for successful tissue integration . However , it has been demonstrated that healing and long-term health of implants could be achieved with equal predictability in a 1-stage , non-submerged approach . This prospect i ve 5-year study not only calculates implant success by life table analysis , but also evaluates the correlation between observed bone level changes with clinical parameters as measured by suppuration , plaque indices , bleeding indices , probing depth , attachment level and mobility . A total of 112 ITI dental implants were inserted in different areas of the jaws .  Clinical and radiographic parameters were evaluated annually for 5 years , whereas a portion of the study group for which 6-year evaluations were available were included in the life-table analysis . The overall success rate after 5 years in service was 99.1 % , while after 6 years it was reduced to 95.5 % due to the fracture of 3 implants in 1 patient . The mean crestal bone loss experienced during the first year was 0.6 mm followed by an annual yearly loss of approximately 0.05 mm . No significant differences could be found between the amount of bone loss measured at each of the yearly follow-up visits . This suggests that statistically the followed implants did not show any radiographically measurable bone loss following the initial period of bone loss associated with implant placement and osseointegration . Low levels of correlation between the individual and cumulative clinical parameters with radiographically measured bone loss suggests that these parameters are of limited clinical value in assessing and predicting future peri-implant bone loss BACKGROUND  Implant restorations  first started with total edentulism . Later , the scientific community gave its approval for restorations in partial edentulism , and only recently some studies confirmed the validity of the treatment for single-tooth replacement . PURPOSE The purpose of the study was to evaluate implant survival and prosthesis stability of Brånemark implants ( titanium screws ) when used routinely for single-tooth replacement in all regions . MATERIAL S AND METHODS Two hundred and fourteen patients received 252 implants for single-tooth replacement over a period of 8 years at five private clinics in Italy . The patients were treated in accordance with the protocol for Brånemark implants , and the data gathered have been analyzed according to established evaluation methods . RESULTS During the observation period , 10 failures were recorded and 229 restorations were carried out . After the first year of loading , the total cumulative survival rate ( CSR ) was 96 % , which then remained stable over the study time . The most frequent complication was loosening of the abutment screws ( n = 22 ) , amounting to 35 % of all 
    Output:
    
For the method of retention ( screw-retained versus cemented ) , no differences were found in implant success or survival rates between screw-retained and cemented restorations .
Prosthesis success rates showed greater variations between cemented and screw-retained restorations at the various evaluation times ; however , the differences never reached statistical significance .
The scientific evidence obtained from this review is insufficient to establish unequivocal clinical guidelines for the design of implant-supported fixed prostheses in the partially edentulous patient