***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: Objectives . The goal of this study was to evaluate bone changes around endosseous implants in partially edentulous patients . Material s and Methods . A total of 632 two-stage implants were placed in 252 patients . The implants had straight emergence profile , ZirTi surface , 3.3 to 5 mm diameter , and 8.5 to 13 mm length . Bone levels were assessed on orthopantomography immediately after surgery and after 36 months and marginal bone loss ( MBL ) was calculated from their difference . Results . Cumulative survival rate was 98.73 % . Overall MBL was 0.8 mm ± 0.03 ( mean ± SEM ) . Higher MBL was observed around implants in the maxilla than in the m and ible ( P < 0.007 ) . A relation between implant diameter and MBL ( P < 0.0001 ) was observed in male and , more limitedly , female patients . Older patients had higher MBL in the maxilla , but not in the m and ible ( P < 0.0001 ) . MBL progressively increased with age in male patients , but reached a peak already in the 50–60 years age group in the female subset ( P < 0.001 ) . Conclusions . The overall MBL is consistent with the available literature . Site difference and patient age and gender appear to significantly affect MBL , representing important factors to be considered during implant placement 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 This study was design ed to radiographically evaluate the effect of surface macro- and microstructures within the coronal portion of the external hex implant at the marginal bone change after loading . The fifty-four patients included in the study were r and omly assigned to treatment groups with rough-surface implants ( TiUnite , n = 45 ) , a hybrid of smooth and rough surface implants ( Restore , n = 45 ) or rough-surface with microthreads implants ( Hexplant , n = 45 ) . Clinical and radiographic examinations were conducted at the time of implant loading ( baseline ) and at 1-year post-loading . A three-level mixed-effect ancova was used to test the significance of the mean marginal bone change of the three implant groups from baseline to 1-year follow-up . At 1-year , significant differences were noted in marginal bone loss recorded for the three groups ( P < 0.0001 ) . The rough surface with microthread implants had a mean crestal bone loss of 0.42 + /- 0.27 mm ; the rough surface implants , 0.81 + /- 0.27 mm ; and the hybrid surface implants , 0.89 + /- 0.41 mm . Within the limitations of this study , a rough surface with microthreads at the coronal part of implant maintained the marginal bone level against functional loading better than implants without these two features PURPOSE To evaluate the influence of macro- and microstructure of the implant surface at the marginal bone level after functional loading . MATERIAL S AND METHODS Sixty-eight patients were r and omly assigned to 1 of 3 groups . The first group received 35 implants with a machined neck ( Ankylos ) ; the second group , 34 implants with a rough-surfaced neck ( Stage 1 ) ; and the third , 38 implants with a rough-surfaced neck with microthreads ( Oneplant ) . Clinical and radiographic examinations were conducted at baseline ( implant loading ) and 3 , 6 , and 12 months postloading . Two-way repeated analysis of variance ( ANOVA ) was used to test the significance of marginal bone change of each tested group at baseline , 3 , 6 , and 12 month follow-ups and 1-way ANOVA was also used to compare the bone loss of each time interval within the same implant group ( P < .05 ) . RESULTS At 12 months , significant differences were noted in the amount of alveolar bone loss recorded for the 3 groups ( P < .05 ) . The group with the rough-surfaced microthreaded neck had a mean crestal bone loss of 0.18 + /- 0.16 mm ; the group with the rough-surfaced neck , 0.76 + /- 0.21 mm ; and the group with the machined neck , 1.32 + /- 0.27 mm . In the rough-surfaced group and the rough-surfaced microthreaded group , no statistically significant changes were observed after 3 months , whereas the machined-surface group showed significant bone loss for every interval ( P < .05 ) . DISCUSSION To minimize marginal bone loss , in addition to the use of a rough surface at the marginal bone level , a macroscopic modification such as the addition of microthreads could be recommended . A rough surface and microthreads at the implant neck not only reduce crestal bone loss but also help with early biomechanical adaptation against loading in comparison to the machined neck design . CONCLUSION A rough surface with microthreads at the implant neck was the most effective design to maintain the marginal bone level against functional loading PURPOSE The purpose of this experimental study was to analyze radiographically in a dog model how different implant-abutment interface configurations influence alveolar crestal bone changes .  MATERIAL S AND METHODS Six different experimental implant-abutment connections were evaluated in six mixed-breed dogs . The following parameters were tested : absence of microgap , microgap proximal to bone crest , and microgap distant from bone crest . In addition , two different cervical abutment profiles , one straight and one featuring a supracrestal concavity , were evaluated . Implants were based on a cylindrical full-body screw design and made from cold-worked grade IV commercially pure titanium . The diameter ( at thread tips ) measured 4.1 mm , whereas the inner diameter was 3.5 mm . St and ardized periapical digital radiographs were obtained for comparative analysis at baseline and at 3 , 4 , 5 , 6 , 7 , 8 , and 9 months after implant placement . Radiographs were r and omized and calibrated for linear measurements . For statistical analysis , mixed-model repeated- measures analysis of variance was used . RESULTS All implants integrated successfully and remained stable during the entire period of the study . Radiographically , when comparing groups with straight profiles , crestal bone remodeling in group C ( one-piece design ) was significantly less than in group A ( matching diameters ) and B ( nonmatching diameters ) . In fact , implant group C showed the least crestal bone remodeling of all groups . When comparing groups with a concave profile but different microgap configurations , all three design s demonstrated bone loss with no significant differences among the three groups . CONCLUSION A nonsubmerged one-piece implant design demonstrated the least amount of bone remodeling of all groups . Implant-abutment connections with a concave profile established crestal bone levels immediately apical to the concavity regardless of the microgap variable PURPOSE The study aims to assess the soft tissue level ( STL ) and crestal bone level ( CBL ) , of  titanium dental implants  with different mixed collar abutments configurations . MATERIAL S AND METHODS This study included 48 implants with the same dimensions . They were divided into two groups of 24 implants each one : implants with a polished collar of 2 mm plus a roughened area of 0.8 mm ( CONTROL ) and implants with a polished collar of 0.8 mm plus a micro-threated and roughened area of 2 mm ( TEST ) . The implants were inserted r and omly in the post- extraction sockets of P2 , P3 , P4 , and M1 bilaterally in the lower jaw of six foxhound dogs .  STL and CBL were evaluated after 8 and 12 weeks by histology and histometry . RESULTS All implants were clinical ly and histologically osseointegrated . Healing patterns examined microscopically at 8 and 12 weeks for both groups yielded similar qualitative findings for the STL evaluation , without significant differences between groups ( P > 0.05 ) . CBL was significantly higher in the buccal side in comparison with the lingual side for both groups ( P < 0.05 ) ; the comparison between groups at 8 weeks showed IS-B ( distance from the implant shoulder to the top of the bony crest ) and IS-C ( distance from the implant shoulder to the first bone-to-implant contact ) values significantly higher for control group in comparison with test ( P < 0.05 ) . At 12 weeks , CBL showed increased values for both groups that were higher in controls group in comparison with test ( P < 0.05 ) . CONCLUSIONS Bony crest resorption could not be avoided both at test and control sites . However , the neck conformation at the test sites reduced the buccal bone resorption . Soft tissue dimensions were similar both at the test and control sites AIM To evaluate the aesthetic outcome of  single-tooth implants in the aesthetic zone with different neck design s from a professional 's and patient 's perception . MATERIAL S AND METHODS Ninety-three patients with a missing anterior tooth in the maxilla were r and omly assigned to be treated with an implant with a smooth neck , a rough neck with grooves or a scalloped rough neck with grooves . Implants were installed in healed sites . One year after definitive crown placement ( 18 months post-implant placement ) , photographs were taken and the aesthetic outcome was assessed according to two objective aesthetic indexes : pink esthetic score/white esthetic score ( PES/WES ) and implant crown aesthetic index ( ICAI ) . A question naire was used to assess the aesthetic outcome and general satisfaction from a patient 's perception . st and ardized radiographs were taken to measure marginal bone level changes . RESULTS One implant was lost . Although there was a significant difference in marginal bone loss between the different implant neck design s ( smooth neck 1.19±0.82 mm , rough neck 0.90±0.57 mm , scalloped neck 2.01±0.77 mm ) , there were no differences in aesthetic outcome . According to the professional 's assessment s using PES/WES and ICAI , 79.3 % and 62 % of the cases showed acceptable crown aesthetics , and 59.8 % and 56.5 % of the cases showed acceptable mucosa aesthetics . Overall , patients were satisfied about the aesthetics of the mucosa ( 81.5 % ) and crown ( 93.3 % ) , and general patient satisfaction was high ( 9.0±1.0 out of a maximum of 10 ) . According to the professional 's assessment , a pre-implant augmentation procedure was associated with less favorable aesthetics of the mucosa . CONCLUSION This study shows that the aesthetics of  single-tooth implants in the maxillary aesthetic zone appears to be independent of the implant neck design s applied but dependent on the need for pre-implant surgery OBJECTIVE To carry out a comparative study of two implants with different neck features and prostheses platform connection ( machined with external connection and rough-surfaced with switching platform ) upon peri-implant marginal bone loss , before and after functional loading . MATERIAL AND METHODS A r and omized , prospect i ve radiological study was made . Eighteen totally edentulous patients were selected . Subjects were divided into two groups according to the type of implant neck used : ( a ) Osseous ( ® ) , with machined surface , without microthreads , external connection , and without platform switching ; and ( b ) Inhex ( ® ) , with treated surface , microthreads , internal connection , and platform switching . Mesial and distal marginal bone loss was measured . Implant success was assessed according to the criteria of Buser . Control timepoints were as follows : ( a ) at implant placement ; ( b ) at prosthesis placement ; ( c ) 6 months after loading ; ( d ) 12 months after loading . RESULTS Fifteen patients that received 120 dental implants were included : 47 % Osseous ( ® ) group and 53 % Inhex ( ® ) group . Global mean marginal bone loss with Osseous ( ® ) was 0.27 ± 0.43 mm and 0.38 ± 0 
    Output:
    
Rough and rough-surfaced microthreaded implants are considered a predictable treatment for preserving early marginal bone loss