***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 The aim of this study was to evaluate the feasibility of using a 2-stage implant system in a single-stage procedure and to study the impact of the microgap between the implant and the abutment . MATERIAL S AND METHODS Sixty edentulous patients ( Cawood class V or VI ) participated in this study . After r and omization , 20 patients received 2 IMZ implants placed in a single-stage procedure , 20 patients received 2 IMZ implants placed in the traditional 2-stage procedure , and 20 patients were treated with 2 ITI implants ( single-stage procedure ) . The implants were placed in the canine area of the m and ible . After 3 months , m and ibular overdentures were fabricated , supported by a bar- and -clip attachment . A st and ardized clinical and radiographic evaluation was performed immediately after prosthesis placement and after 12 and 24 months . RESULTS One IMZ implant of the 1-stage group and 1 IMZ implant of the 2-stage group were lost after 6 and 12 months , respectively . Apart from several significant but clinical ly irrelevant differences , the 3 groups did not appear to differ markedly with regard to clinical parameters during the evaluation period . The mean bone loss within the first 2 years of functioning ( 1.1 mm IMZ 1-stage , 0.8 mm IMZ 2-stage , 1.2 mm ITI ) was comparable for the 3 groups . DISCUSSION AND CONCLUSIONS The results of this study suggest that dental implants design ed for a submerged implantation procedure can also be used in a single-stage procedure and may be as predictable as when the same implants used in a 2-stage procedure or as 1-stage implants . Placement of the microgap at the crestal level in 2-stage implants did not appear to have an adverse effect on the amount of peri-implant bone loss at 2 years in this study population AIM The aim of this study was to compare the clinical outcome of submerged vs. non-submerged tapered implants placed into fresh extraction sockets . MATERIAL S AND METHODS A prospect i ve , controlled , multicenter , r and omized , clinical trial has been performed in two centers in Rome and Torino ( Italy ) . Thirty healthy patients were recruited according to the following inclusion criteria : need for an immediate post extraction implant , ages between 18 and 70 , horizontal defect depth < 2 mm , smokers < 10 cigarettes/day and absence of any circumstance or condition that could represent contraindications to implant surgery . The patients were r and omly allocated to submerged or non-submerged treatment groups immediately after flap elevation and tooth extraction . Submerged implants were exposed 8 weeks after the first surgery ; all implants were loaded with provisional restorations 12 weeks after the first surgery and with definitive restoration 12 weeks thereafter . Clinical and radiographic parameters were evaluated at baseline , at implant loading and at the 1-year follow-up visit . RESULTS The results showed statistically significant differences between the two groups in the mean value of keratinized tissue ( KT ) height after surgery that was significantly reduced for submerged implants when compared with transmucosal implants ( mean reduction of KT at year follow-up : T group 0.2 mm , S group 1.3 mm ; P=0.007 ) . CONCLUSION Similar outcomes were found for submerged and non-submerged implants placed in fresh extraction sockets with a horizontal peri-implant defect smaller than 2 mm , except for a reduction of KT in the submerged group . Either with a submerged or a non-submerged procedure , 1 mm of mean soft tissue recession is seen after 1 year when compared with the pre- extraction situation The osseointegration of endosseous dental implants is well documented . Implants have proven to be a viable treatment option for the replacement of missing teeth . The surgical phase of implant dentistry for most implant systems involves two stages — the placement of the implant and its subsequent uncovering . The IMZ ( Interpore International ) implant system is classically a two-stage system . No significant differences were demonstrated in osseointegration and soft tissue healing for IMZ implants placed in one-stage and two-stage procedures in this pilot study In the present multi-center study , non-submerged ITI implants were prospect ively followed to evaluate their long-term prognosis in fully and partially edentulous patients . In a total of 1003 patients , 2359 implants were consecutively inserted . Following a healing period of 3 - 6 months , the successfully integrated implants were restored with 393 removable and 758 fixed restorations . Subsequently , all consecutive implants were documented annually up to 8 years . At each examination , the clinical status of all implants was evaluated according to predefined criteria of success . Therefore , the data base allowed the evaluation of 8-year cumulative survival and success rates for 2359 implants . In addition , cumulative success rates were calculated for implant subgroups divided per implant type , implant length , and implant location . Furthermore , the actual 5-year survival and success rates could be determined for 488 implants . During the healing period , 13 implants did not successfully integrate , whereas 2346 implants fulfilled the predefined criteria of success . This corresponds with an early failure rate of 0.55 % . During follow-up , 19 implants were classified as failures due to several reasons . In addition , 17 implants ( approximately 0.8 % ) demonstrated at the last annual examination a suppurative periimplant infection . Including 127 drop out implants (= 5.4 % drop out rate ) into the calculation , the 8-year cumulative survival and success rates result ed in 96.7 % and 93.3 % , respectively . The analysis of implant subgroups showed slightly more favorable cumulative success rates for screw type implants ( > 95 % ) compared to hollow-cylinder implants ( 91.3 % ) , and clearly better success rates for m and ibular implants ( approximately 95 % ) when compared to maxillary implants ( approximately 87 % ) . The actual 5-year survival and success rates of 488 implants with 98.2 % and 97.3 % , respectively , were slightly better than the estimated 5-year cumulative survival and success rates of 2359 implants indicating that the applied life table analysis is a reliable statistical method to evaluate the long-term prognosis of dental implants . It can be concluded that non-submerged ITI implants maintain success rates well above 90 % in different clinical centers for observation periods up to 8 years BACKGROUND The use of a submerged implant system in a nonsubmerged surgical procedure has been reported to have promising results . At the time this study was initiated , no prospect i ve , comparative studies with r and omization between submerged and nonsubmerged surgical techniques had been published . PURPOSE To evaluate the submerged and nonsubmerged surgical techniques when treating m and ibular edentulism using a submerged implant system , with regard to implant survival and complications . MATERIAL S AND METHODS A total of 77 patients were included and treated at nine clinics in Sweden and Norway . In total , 404 Brånemark System implants ( st and ard and MkII implants ) were inserted in the edentulous m and ible ; 198 implants according to the nonsubmerged protocol and 206 implants according to the traditional submerged procedure . The follow-up period was up to 36 months after prosthesis insertion . RESULTS In the nonsubmerged group , 17 implants out of 198 implants ( 8.6 % ) were lost and in the submerged group , 5 out of 206 implants ( 2.4 % ) were lost . All implant failures occurred before the delivery of the final prosthesis . No major complications were reported during the implant surgery . However , at the clinical check-up postoperatively and at the abutment connection surgery , 6 patients in the nonsubmerged group complained of pain at the implant sites , whereas there were no complaints of pain in the submerged group . CONCLUSIONS The results of this study suggest that a turned Brånemark implant design ed for a submerged implant placement procedure can be used in a nonsubmerged procedure and may be as predictable as the conventional submerged approach The aim of this prospect i ve study was to compare the clinical integration and survival of Brånemark fixtures when using the conventional 2-stage surgical procedure to 1-stage surgical approach in completely and partially edentulous m and ibles . A total of 85 patients were consecutively treated for partial ( n = 35 ) or complete ( n = 50 ) m and ibular edentulousness . Fixtures removed because of mobility , pain or infection were counted as failures . The first 10 patients of each group were selected for radiographical analysis of crestal bone changes 1 year after prosthesis insertion . In 33 patients with edentulous m and ibles , 170 fixtures were placed in a 1-stage approach . In this group , 4 fixtures ( 2.4 % ) were lost prior to prosthetic restoration . Seventeen edentulous patients received a total of 70 fixtures in a 2-stage procedure . Out of these , 5 fixtures ( 7.1 % ) were lost at abutment connection . In 17 partially edentulous patients , 41 fixtures were inserted in a 1-stage approach . Two fixtures ( 5 % ) were lost in this group . Finally , 18 partially edentulous patients received a total of 49 fixtures in a 2-stage procedure . Out of these , 6 fixtures ( 12 % ) were lost at abutment connection . In total 313 of the 330 installed m and ibular implants were loaded between 6 and 12 months ( 94.8 % success ) . No further losses occurred in the implants functioning at least 1 year ( 267 implants ) or at least 2 years ( 59 implants ) . Statistical analysis ( Chi square test ) revealed no difference in fixture survival between the treatment modalities . Radiographical analysis after 1 year of functional loading showed the typical bone resorption changes up to the most coronal implant thread in both modalities . Although this study pertains to relatively early loading of 2 years , the results seem to indicate that in the m and ible a 1-stage surgical approach with Brånemark fixtures may be as predictable as the conventional 2-stage procedure OBJECTIVE To evaluate bone-level alterations that occurred at implants of the Astra Tech(R ) System that were placed in the load carrying , posterior parts of the dentition using either a submerged ( two-stage ) or a non-submerged ( one-stage ) installation protocol . MATERIAL AND METHODS Eighty-four patients that required 115 fixed partial dentures ( FPDs or cases ) entered the prospect i ve study . All subjects were assigned one patient and > or = one case numbers . For the r and omization of cases , a custom-made program based on balanced r and om permuted blocks was utilized . The cases were assigned to two treatment groups , namely one-stage installation procedure , non-submerged technique ( group A ) and two-stage installation procedure , submerged technique ( group B ) . Several subjects contributed with cases to both groups A and B. Periodontal , endodontal and open caries lesions were treated prior to implant installation . All patients received careful oral hygiene instruction and training in self-performed plaque control measures . The surgical technique used for fixture installation followed the outline described in the manual for the Astra Tech System . The FPDs were placed 3 months ( m and ible ) and 6 months ( maxilla ) following implant installation . Immediately following FPD placement , a baseline examination was performed that included assessment of plaque , soft-tissue inflammation and bone level . Clinicians who were otherwise not involved in the study performed the radiographic measurements . Clinical and radiographical examinations were repeated once a year after the baseline examination . DATA ANALYSIS The primary outcome variable was the change in the bone level at the implants from the time of placement of the bridge ( FPD ) to the 1- and 2-year reexaminations . Fisher 's permutation test was used to test if differences existed between groups A and B , and between patients ( men/women , smokers/non-smokers , age ) , sites ( maxilla/m and ible ) and implants ( length , diameter ) . Pitman 's test was used to study correlations between bone shape and quality data and different radiographic bone-level data . RESULTS It was demonstrated that tissue healing following implant installation appeared to be independent of the surgical protocol , i.e. whether the marginal portions of the implants during surgery were fully or only partly submerged under the ridge mucosa . Thus , ( i ) in both treatment groups the number of implants that failed to osseointegrate ( early failures ) was small ( < 2 % ) ; ( ii ) at the end of the recommended periods of bone healing prior to loading , - in both groups , maxilla=6 months and m and ible=3 months - the level of the marginal bone was close to the coronal rim of the fixture ; group A : 1.54+/-0.92 mm , group B : 1.31+/-0.77 mm . The current study also demonstrated that irrespective of surgical protocol ( two-stage , one-stage ) , implants supporting the FPDs exhibited only small amount of radiographic bone loss during the first year of function ( group A : 0.02+/-038 mm , group B : 0.17+/-0.64 mm ) . Moreover , during the second year of function , the amount of additional bone loss that occurred in the two treatment groups was close to zero . CONCLUSION Periimplant bone-level change during function seemed to be unrelated to whether initial soft- and hard-tissue healing following implant installation had occurred under submerged or non-submerged conditions OBJECTIVE The aim of this study was to evaluate the 
    Output:
    
On a patient , rather than per implant basis , the meta-analyses showed no statistically significant differences for prosthesis and implant failures , though trends , especially in fully edentulous patients , favoured 2-stage ( submerged ) implants .
The 1-stage approach might be preferable in partially edentulous patients since it avoids one surgical intervention and shortens treatment times , while a 2-stage submerged approach could be indicated when an implant has not obtained an optimal primary stability or when barriers are used for guided tissue regeneration , or when it is expected that removable temporary prostheses could transmit excessive forces on the penetrating abutments especially in fully edentulous patients