***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: BACKGROUND A new generation of ITI implants , including a hollow cylinder , a hollow screw , and a solid screw , was described in 1988 . Currently , the solid screw is the main alternative . PURPOSE The aim of this study was to gain further clinical documentation of ITI solid-screw implants used in the edentulous upper jaw . This is a report 1 year after loading . MATERIAL S AND METHODS Twenty-eight patients with edentulous upper jaws ( mean age , 57 yr ) were supplied with four to eight ITI solid-screw implants in the upper jaw . In total , 167 implants ( 3.3 and 4.1 mm in diameter ) were inserted . The implants were loaded about 7 months postoperatively . All patients were supplied with fixed screw-retained bridges . RESULTS Twelve implants failed : 10 prior to loading and 2 after . Overall implant survival rate was 92.8 % . Three of the five patients with implant loss were smokers .  Signs of peri-implantitis were found in seven patients , affecting 12 implants . Mean marginal bone level at the loading of the implants ( 7 months after insertion ) was situated 4.7 mm from the reference point of the implant . There was no significant change between loading and the 1-year examination . However , at several implants , the bone level at baseline was situated far apical of the reference point , indicating a bone loss before loading . CONCLUSIONS The ITI screw implants , used in the edentulous upper jaw , had a survival rate of 92.8 % . Mean bone loss between loading and the 1-year examination was 0.1 mm . Some implants had a bone level indicating a significant bone loss before loading . Peri-implantitis was found at about 7.2 % of the implants inserted and at 25 % of the failing implants BACKGROUND Brånemark fixtures were originally placed in two stages , whereas titanium plasma-sprayed ( TPS ) solid-screws are placed in one stage . Long-term survival rates for both types of implants are excellent . Excellent survival rates have also been reported for machined screw-shaped ( MS ) titanium implants placed in one stage . A small number of studies have compared different implant systems and methods of implant placement . PURPOSE The purpose of this study is to report clinical outcomes from a prospect i ve longitudinal , multicenter study comparing Brånemark MS fixtures ( Nobel Biocare , Yorba Linda , California , USA ) placed in either one or two stages with a one-stage TPS system ( ITI Straumann , Waldenburg , Switzerl and ) . METHODS A protocol was design ed to compare implant survival rates , changes in crestal bone for titanium MS fixtures placed in one and two stages , and plasma-sprayed solid-screw fixtures placed in one surgical stage .  Twenty-nine patients ranging in age from 24 to 82 years received MS fixtures in one stage .  The average age for males was 58 years ( n = 11 ) , whereas the ages for females ( n = 18 ) ranged from 15 to 84 years ( average 58 years ) . Twenty-nine patients received machined titanium fixtures placed in two stages . There were 20 females ranging in age from 23 to 74 years ( average 54 years ) and 9 females ranging from 24 to 74 years ( average 46 years ) . Twenty-five patients received TPS fixtures .  There were 15 males , ranging in age from 57 to 79 ( average 70 ) , and 10 females , ranging in age from 40 to 83 years ( average 62 years ) .  Bone quality and quantity were determined from radiographs and during site preparation . Patient age , sex , location of implant placement according to jaw , length of fixtures , and number of lost fixtures were entered onto computer code sheets and continuously entered into a locked computer system . For one- and two-stage MS fixtures , nonst and ardized periapical radiographs were taken at abutment connection and follow-up . Solid screws were x-rayed at prostheses connection and follow-up . The average time between implant restoration and radiographic follow-up was 15 months . The x-rays were scanned into a computer , and a program design ed to measure radiographs was used to determine changes in crestal bone . Measurements for one- and two-stage MS fixtures were made from the top of the implant shoulder to the first bone to implant contact mesial and distally . Plasma-sprayed screws were measured from the bottom of the implant to the coronal most bone to implant contacts mesial and distally . Mesial-distal radiographic measurements were averaged and changes were compared using the t-test for related sample s. RESULTS This report presents data from the 2- to 3-year follow-up examinations . Twenty-nine patients received 80 one-stage MS fixtures .  Between 0 and 1 year , two fixtures were lost , result ing in a 97.5 % cumulative survival rate ( CSR ) . The CSR remained unchanged through the 2- to 3-year follow-up . Twenty-eight patients received 78 two-stage MS fixtures . One implant was lost prior to loading and two were lost between 0- and 1-year follow-up , yielding a 96.2 % CSR at the end of 1 year . The CSR remained unchanged through the 2- to 3-year follow-up . Twenty-three patients received 78 solid-screw plasma-sprayed screws . One implant was lost prior to loading and one between the 0- to 1-year follow-up , accounting for a 97.4 % CSR at the 2- to 3-year follow-up . Changes in bone crest measurements for one-stage titanium threaded fixtures were insignificant ( -0.11 mm , p = .08 , maxillary ; 0.07 mm , p = .42 , m and ibular ) . For two-stage MS fixtures , crestal bone loss was insignificant in maxillae ( -0.16 mm , p = .92 ) and significant in m and ibles ( -0.43 mm , p = .000 ) . There was significant bone loss for TPS implants in maxillae and m and ibles ( maxillae , 1.31 mm , p = .04 ; m and ibles , 0.98 mm , p = .000 ) . CONCLUSIONS Cumulative survival rates for MS fixtures placed in one and two stages as well as one-stage TPS screws up to the 2- to 3-year follow-up examination were similar , indicating excellent clinical results . Radiographic measurements for changes in crestal bone loss were clinical ly insignificant for fixtures placed in one stage . For two-stage fixtures , maxillary changes were insignificant , whereas m and ibular bone loss was statistically significant but clinical ly insignificant . Changes in crestal bone loss for TPS implants were statistically significant BACKGROUND A major reason for the success of modern dental implant systems has been the development of implant design s that enhance direct bone-implant interface . Surface roughness has been a factor in this success and different systems have utilized very different implant surface roughness . The major purpose of this study was to evaluate 2 similar implants with different surface roughness characteristics . METHODS Two similarly design ed , screw-type , commercially pure titanium implants , one dual acid-etched ( DAE ) and the other machined-surfaced ( MS ) , were compared in this prospect i ve , r and omized-controlled , multi-center study , in which a total of 97 patients were enrolled at a private dental practice or a university dental clinic . Both implant types were placed in each patient using a 2-stage approach with a conventional 4- to 6-month healing period . Implants supported fixed prostheses , hybrid prostheses , and overdentures as dictated by the individual patient 's need . All of the cases were followed using clinical and radiographic examinations . Criteria of success were the absence of peri-implant radiolucency , mobility , and persistent signs or symptoms of pain or infection . RESULTS Of the 432 implants ( 247 dual acid-etched , 185 machined-surfaced ) , 36 implants ( 12 dual acid-etched and 24 machined-surfaced ) have failed . The pre-loading integration success rate of the dual acid-etched implants ( 95.0 % ) was statistically higher ( P < 0.01 ) than the success rate of the machined-surfaced implants ( 86.7 % ) . At 36 months , the cumulative success rates ( CSR ) are 95.0 % for the dual acid-etched implants and 86.7 % for the machined-surfaced implants . CONCLUSIONS The difference in success rates is most likely attributed to the acid-etched surface characteristics . The greatest performance difference is observed in the conditions of poor quality or soft bone where the 3-year post-loading CSR are 96.8 % ( dual acid-etched ) and 84.8 % ( machined-surfaced ) PURPOSE This investigation was conducted to obtain preliminary roughness data on a microtextured implant surface and to determine its ability to sustain a 1-stage surgical procedure and early full occlusal loading of single-tooth restorations in humans . MATERIAL S AND METHODS Three-dimensional ( 3D ) vertical scanning interferometry was conducted on sample s of the test surface ( MTX ) and 2 control surfaces ( Osseotite and s and blasted/acid-etched [ SLA ] ) . Test implants were also placed in vivo , restored with fully occluding single-tooth restorations ( n = 27 ) after 2 months of nonsubmerged healing , and clinical ly monitored for 48 months of follow-up . RESULTS Microtexture was relatively uniform on the test surface and more r and om and irregular on the control surfaces . MTX and Osseotite were similar in some roughness parameters , but the MTX surface had a greater number of micropits that were spaced closer together ( Stylus Y lambda q ) and with higher slope values ( Stylus Y delta q ) . Cumulative life table results were 100 % for all MTX implants placed in maxillary and m and ibular jaw locations , and no discernible marginal bone changes were observed . Overall implant success was 100 % after 4 years of clinical functioning . DISCUSSION The findings of this study appear promising but should be considered preliminary , because of the limitations in the number of locations measured on each product sample and the small number of implants clinical ly studied . CONCLUSION Within the scope of the present study , MTX implants exhibited a uniform micropitted surface , as well as 100 % survival and 100 % clinical success after nonsubmerged placement , early loading with single-tooth restorations at 2 months , and 48 months of clinical functioning . ( More than 50 references . PURPOSE To evaluate the bone contact percentage around a proprietary high-temperature dual-etched ( DE ) implant surface ( Osseotite ) versus implants with machined , hydroxyapatite ( HA ) , and titanium plasma-sprayed ( TPS ) surfaces . MATERIAL S AND METHODS Each implant type was placed in rabbit tibiae of the same animal and assessed at 1 to 8 weeks . Histologic sections were prepared and analyzed histomorphometrically . RESULTS The DE implant surface achieved higher levels of bone contact percentage than the other surfaces . This enhanced contact level was apparent by 3 weeks and seen at all time intervals except 2 weeks , at which machined exceeded the DE mean . In evaluating which surface outscored the others in each individual rabbit , there was a statistically significant confidence for the DE surface ( P < .001 ) . The other 3 surfaces failed to show significance , although the numeric scores for the TPS surfaces were below r and om expectations and the machined scores were slightly above . There was no correlation between degree of roughness and bone contact percentage . DISCUSSION Arbitrarily roughening the implant surface may not result in a large change in bone conductivity . The specific texture of the DE process yielded more contact , possibly as the result of better fibrin clot retention and growth factor enhancement . CONCLUSIONS There was no advantage demonstrated in this model to an HA surface over titanium . The bone contact to the rough HA surface scored similarly to that for the TPS surface of similar roughness , and well below that for the DE titanium surface . The DE surface appeared to have an advantage in bone contact percentage , particularly in early healing in a rabbit tibia model The aim of this study was to evaluate the influence of implant microstructure on the osseointegration of immediate implants placed into infected sites . During 12 weeks , periodontitis was induced in six dogs in the areas of the first to fourth m and ibular premolars of both sides . The teeth were extracted and the implants were placed immediately . Implant placement was r and omly assigned so that for each side in the m and ible a different implant surface , a new grit-blasted/acid-etched group 1 or titanium plasma spray surface group 2 was used , totaling 36 implants in the experiment . The animals were killed 12 weeks after implant placement . Two histomorphometric analyses were performed : percentage of bone/implant contact ( BIC ) and analyses of the bone density in adjacent and distant areas from the implant surface . The results showed that the percentages of BIC were 52.7 % and 42.7 % for groups 1 and 2 , respectively . The bone density analysis revealed that the percentages of bone in the adjacent areas were 66.6 % and 58.8 % , and in the distant areas from the implants were 58.7 % and 55.8 % for groups 1 and 2 , respectively . The mean differences of BIC were verified through the Mann 
    Output:
    
RESULTS AND DISCUSSION A huge number of the experimental investigations have demonstrated that the bone response was influenced by the implant surface topography ; smooth ( S(a)<0.5 microm ) and minimally rough ( S(a ) 0.5 - 1 mum ) surfaces showed less strong bone responses than rougher surfaces .
* Surface topography influences bone response at the micrometre level . *
Some indications exist that surface topography influences bone response at the nanometre level . *