***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 paper describes the 5-year results of a comparative study between Astra Tech and Brånemark system implants . The aim was to compare the systems primarily with regard to bone level changes , and also with regard to other variables of interest . Sixty-six patients with edentulous jaws were included in the study . R and omisation schedules were used to allocate the patients to the two implant systems . 184 Astra Tech implants with a titanium-blasted surface and 187 Brånemark implants with a turned surface were used . The implants were inserted with a two-stage technique and the insertion followed the routines for the respective implant system . All patients were provided with full-arch fixed bridges . All patients were followed up with clinical and radiographic examinations from fixture insertion to the 5-year follow-up . The total mean bone level change in the upper jaw between fixture insertion and the 5-year examination was -1.74+/-0.45 mm at the Astra implants and -1.98+/-0.21 at the Brånemark implants . The corresponding values for the lower jaw were -1.06+/-0.19 for Astra and -1.38+/-0.17 for Brånemark . The major postoperative changes of the marginal bone level took place between fixture insertion and baseline . During this period , there was also a different pattern of bone remodelling between the implant systems . Between baseline ( prosthesis connection ) and the 5-year examination , the marginal bone level changes were small , with no difference between the implant systems . The implant stability was examined with the supraconstructions removed . At the 5-year examination , the survival rate for Astra Tech implants was 98.4 % and for the Brånemark implants it was 94.6 % . The difference was not statistically significant 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 PURPOSE A prospect i ve study on m and ibular implant-supported overdentures using more than 2 Brånemark implants splinted with multiple round bars evaluated a hypothesis that unnecessary prosthodontic maintenance would result from the contravention of accepted biomechanical principles . MATERIAL S AND METHODS A r and omized prospect i ve trial on 59 edentulous patients details prosthodontic maintenance and complications of 52 m and ibular overdentures ( 11 unsplinted , 41 splinted ) over a 3-year period . RESULTS Prosthodontic maintenance was greater in the first year than in subsequent years , regardless of design . Comparison between the splinted design s with round bars revealed no statistically significant difference with either retentive clip activation or fractures . More than 70 % of the retention clips in the 2-implant ( single round bar ) design needed activation , as compared to 44 % of those with the 3-implant ( double round bar ) or 4-implant ( triple round bar ) design . Retention clip fracture occurred in 30 % of patients with 3 or 4 implants and 16 % of those with 2 implants . Relining the overdentures , regardless of design , revealed an excessive maintenance burden in 40 % of overdentures . Remaking of overdentures was necessary in 21 % of patients . CONCLUSION Multiple round bars splinting 3 or 4 implants can still be a treatment concept in m and ibular overdenture treatment . Results from prospect i ve evaluation of this design indicate less prosthodontic maintenance of clip activation but more clip fractures than with 2 implants splinted with single round bars , although not at statistically significant levels This report is an up date on a group of 46 clinical trial patients who each received 3 free-st and ing Endopore dental implants placed using a 2-stage surgical approach in the anterior m and ible . After an initial healing interval of 10 weeks , the implants were used in each case to retain an over-denture , and at the time of the report , all patients had passed 5 years of continuous function . The 5-year cumulative " survival " rate based on a life table analysis was 93.4 % and this remained unchanged after 6 years . The 5-year " success rate " was 83.3 % when assessed qualitatively with the published criteria of others using a four-field table analysis categorizing every implant in the study as one of " Grade 1 Success " , " survival " , " unaccounted for " or " failure " . Modified periodontal parameters verified continued peri-implant soft tissue health . No implant still in function had more than 1.8 mm cumulative bone loss during the first 5 years of function . These results provide clear evidence that Endopore implants despite their short lengths function at least as well as other dental implant design s used in much longer lengths PURPOSE This r and omized controlled clinical trial aim ed to evaluate the efficacy of splinted implants versus unsplinted implants in overdenture therapy over a 10-year period . MATERIAL S AND METHODS The study sample comprised 36 completely edentulous patients , 17 men and 19 women ( mean age 63.7 years ) . In each patient , 2 implants ( Brånemark System , Nobel Biocare , Göteborg , Sweden ) were placed in the interforaminal area . Three to 5 months after placement , they were connected to st and ard abutments . The patients were then rehabilitated with ball-retained overdentures , magnet-retained overdentures , or bar-retained overdentures ( the control group ) . Patients were followed for 4 , 12 , 60 , and 120 months post-abutment connection . Group means as well as linear regression models were fitted with attachment type and time as classification variables and corrected for simultaneous testing ( Tukey ) . RESULTS After 10 years , 9 patients had died and 1 was severely ill . Over 10 years , no implants failed . Mean Plaque Index , Bleeding Index , change in attachment level , Periotest values , and marginal bone level at the end of the follow-up period were not significantly different among the groups . DISCUSSION The annual marginal bone loss , excluding the first months of remodeling , was comparable with that found around healthy natural teeth . CONCLUSION The fact that no implants failed and that overall marginal bone loss after the first year of bone remodeling was limited suggested that implants in a 2-implant m and ibular overdenture concept have an excellent prognosis in this patient population , irrespective of the attachment system used 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 Maintenance of the health and integrity of the bone-implant complex ( osseointegration ) has been shown to be essential for long term success of root-form , endosseous dental implants .  If reliable clinical indicators of adequacy of the bone-implant complex existed , they could stimulate new and innovative early intervention research to arrest of reverse early deterioration of the bone-implant complex . In the absence of such indicators , this has been problematic . The Periotest may have the potential to provide this information by indirectly assessing the status of the bone-implant complex . However , little information is available that documents either the capability of the Periotest to reliably assess changes of the bone-implant complex or the " normal variations " in Periotest values ( PTVs ) for both HA-coated and non-coated implants . METHODS The purpose of this paper was to document changes in PTVs as influenced by various implant surfaces , implant design s , and bone densities . The mean PTVs recorded for each visit , for all implant types and bone densities , were combined to provide an overall average PTV ( A-PTV ) . The changes in stability ( PTVs ) were analyzed using a generalized linear model ( GLM ) with repeated measures ( Hotelling 's Trace ) . RESULTS The A-PTV for all implants over all visits was -3.5 . The mean PTVs ranged from -4.2 ( SD = 2.4 ) at uncovering to -3.9 ( SD = 2.9 ) at 60 months . All implants in bone qualities 1 and 2 ( BQ-1 and BQ-2 ) became more stable over time , while those in bone quality 3 or 4 ( BQ-3 and BQ-4 ) showed a slight decrease in stability . In BQ-1 , the mean PTVs increased from -4.7 at uncovering to -4.9 at 60 months . A similar increase in stability occurred in BQ-2 ( -4.1 at uncovering to -4.4 at 60 months ) . In BQ-3 , the stability of the implants decreased over time ( -3.6 at uncovering to -2.9 at 60 months ) , with similar changes recorded for BQ-4 ( -2.5 at uncovering to -1.0 at 60 months ) . When comparing the stability of all HA-coated with all non-coated implants , the HA implants became less stable ( -4.4 to -3.4 ) over time , while non-coated implants showed an improvement in stability ( -3.5 to -4.5 ) . The changes in stability found in BQ-1 , BQ-2 , and BQ-3 were similar , with HA implants becoming less stable and non-coated more stable . HA- and non-coated comparisons were not possible in BQ-4 since there were too few non-coated implants placed in this type of bone . The HA-coated screw showed a decrease in stability when compared to the non-coated screw . CONCLUSIONS Conclusions of the study are as follows : 1 ) PTVs are influenced by bone quality and surface coating of the implant ; 2 ) the PTVs at the time of uncovering provide the best estimate of a clinical ly acceptable PTV for that bone-implant complex ; 3 ) while the PTVs for any bone-implant complex may fluctuate + /- 1.0 around the uncovering PTV during routine healing and loading of the implant , a consistent shift toward a positive PTV that approaches " 0 " should be cause for concern that the bone-implant complex may be at risk of failure ; 4 ) HA-coated implants became slightly less stable ( more positive PTVs ) over time , while the non-coated implants became more stable ( more negative PTVs ) ; and 5 ) until a " critical PTV " can be accurately identified , it is suggested that a consistent shift in recorded PTVs that exceeds the + 3.0 value on the PTV scale should be viewed with concern for possible deterioration at the bone-implant complex The aim of this prospect i ve r and omized controlled clinical trial was to evaluate and compare clinical aspects and satisfaction during the first year following treatment and consecutively the change in treatment during the next 4 years of follow-up . Patients were allocated to one of the following treatment modalities : an implant-retained overdenture ( IRO-group , 2 endosseous implants , n 
    Output:
    
The observation of greater implant failure for removable over fixed protheses groups in the maxilla appeared likely due to deficient preoperative bone volume in the removable prosthesis groups .
DISCUSSION There is little evidence that implant survival or success is affected directly by prosthesis type based on current design s studied for at least 5 years .
Prosthesis maintenance does appear to vary with different prosthesis design s. CONCLUSION While this study suggests implant survival and success may not be affected by variation across the established types of implant prostheses , maintenance dem and s can vary with implant prosthesis type , especially with overdenture attachments .