Preservation of peri-implant soft and hard tissues using platform switching of implants placed in immediate extraction sockets: a proof-of-concept study with 12- to 36-month follow-up. Effect of different prosthetic abutments on peri-implant soft tissue. A randomized controlled clinical trial. Early loading of nonsubmerged titanium implants with a sandblasted and acid-etched (SLA) surface: 3-year results of a prospective study in partially edentulous patients. Clinical and radiographic evaluation of soft and hard tissue changes around implants: a pilot study. The peri-implant hard and soft tissues at different implant systems. A comparative study in the dog. Early loading of non-submerged titanium implants with a sandblasted and acid-etched surface. 5-year results of a prospective study in partially edentulous patients. Influence of frequent clinical probing during the healing phase on healthy peri-implant soft tissue formed at different titanium implant surfaces: a histomorphometrical study in dogs. A systematic review of marginal soft tissue at implants subjected to immediate loading or immediate restoration. A 4-year prospective study to assess peri-implant hard and soft tissues adjacent to titanium versus gold-alloy abutments in cemented single implant crowns. Early loading of sandblasted and acid-etched titanium implants in the edentulous mandible: a prospective 5-year study. Six-Year Radiographic, Clinical, and Soft Tissue Outcomes of Immediately Loaded, Straight-Walled, Platform-Switched, Titanium-Alloy Implants with Nanosurface Topography. A 5-year longitudinal study of the clinical effectiveness of ITI solid-screw implants in the treatment of mandibular edentulism. Ten‐year hard and soft tissue results of a pilot double‐blinded randomized controlled trial on immediately loaded post‐extractive implants using platform‐switching concept Influence of abutment material on the gingival color of implant-supported all-ceramic restorations: a prospective multicenter study. Biologic width around different implant-abutment interface configurations. A radiographic evaluation of the effect of horizontal offset and concave abutment profile in the canine mandible. Soft tissue response to zirconia and titanium implant abutments: an in vivo within-subject comparison. Peri-implant bone level around implants with platform-switched abutments: preliminary data from a prospective study.
PURPOSE The purpose of this article is to evaluate the soft- and hard-tissue response to immediately placed implants . In addition , assessment was conducted of the soft tissue response to a transmucosal abutment which was narrower than the implant platform . MATERIAL S AND METHODS This study was conducted to evaluate 10 consecutively placed immediately loaded implants placed in extraction sockets in maxillae without compromised bone tissue . The infection control phase of periodontal therapy was completed in the areas of hopeless teeth prior to extraction . Implants with a 6-mm-platform diameter were placed immediately into the fresh extraction sockets . A provisional 4-mm-diameter transmucosal abutment was subsequently connected , and a provisional crown was adapted and adjusted for nonfunctional immediate positioning . Three months following implant placement , definitive prosthetic rehabilitation was performed . At the time of prosthesis insertion ( baseline ) and every 6 months thereafter , radiographic assessment s , pocket probing depth ( PPD ) , recession , and papilla height were measured . An image analysis software application was used to compare the radiographic bone crestal bone heights at the mesial and distal aspects of the implants . RESULTS Nine patients with 10 sites were treated . Mean follow-up time was 22 months ( range , 18 to 36 months ) . All 10 implants were found to be clinical ly osseointegrated . Software analysis of radiographic films showed a bone resorption of 0.78 + /- 0.36 mm . The mean values were significantly lower ( P < or = .005 ) than a mean reference value of 1.7 mm . PPD did not exceed 3 mm in any site ( average , 2.8 mm ) . Rather than recession , there was a mean gain in the buccal margin of 0.2 mm and a mean gain in papilla height of 0.25 mm . CONCLUSION This proof-of-concept study suggests that immediate loading with platform switching can provide peri-implant hard tissue stability with soft tissue and papilla preservation . ( Case Series PURPOSE This r and omized clinical trial assessed the effect of three different prosthetic abutments ( titanium , gold-hue titanium and zirconia ) on peri-implant soft tissue 2 years after treatment in partially edentulous subjects . METHODS Baseline data concerning ( 1 ) thickness of the buccal peri-implant soft tissue , ( 2 ) soft tissue thickness above the bone crest , ( 3 ) depth/length of transmucosal pathway , and ( 4 ) periodontal biotype at adjacent teeth were collected . The final sample consisted of 47 subjects ( 21 males , 26 females ) with a total of 97 implants . A two-level ( patient , implant ) statistical model was applied . RESULTS At the 2-year clinical observation , recession of the gingival margin was observed only at 13 % of implants irrespective of the type of abutment . No significant correlation between periodontal biotype at adjacent teeth and peri-implant biotype was observed . Furthermore , none of the investigated variables at patient level ( age , gender , implant type , periodontal biotype ) or at implant level ( keratinized tissue thickness , probing depth , soft tissue thickness ) was identified as a significant predictor of recession . In conclusion , this study pointed out that ( 1 ) abutment type was not able to influence peri-implant variables after 2 years , and ( 2 ) caution should be used in considering periodontal biotype at patient level as a possible indicator of the future peri-implant biotype PURPOSE The aim of this study was to evaluate the success rate of ITI implants with the SLA surface that were loaded after 6 weeks of healing . MATERIAL S AND METHODS In this prospect i ve cohort study , a total of 104 implants were placed in posterior sites of 51 partially edentulous patients exhibiting bone densities of Class 1 , 2 , or 3 . After a healing period of 6 weeks , all implants were functionally loaded with cemented crowns or fixed partial dentures . The patients were recalled at 3 , 12 , 24 , and 36 months for clinical and radiographic examination . RESULTS One implant failed to integrate during healing , and 1 implant was lost to follow-up and considered a dropout . The remaining 102 implants showed favorable clinical and radiographic findings and were considered successfully integrated at the 3-year examination . This result ed in a 3-year success rate of 99.03 % . DISCUSSION The peri-implant soft tissues were stable over time , as evidence d by no changes in the mean probing depths and the mean attachment levels during the follow-up period . None of the radiographs exhibited signs of continuous peri-implant radiolucency , which confirmed ankylotic stability of all 102 implants . The radiographic evaluation of the bone level at the implant indicated stability of the bone crest levels . CONCLUSION The results of this prospect i ve study demonstrated that early loading of ITI implants with the SLA surface after an unloaded healing period of 6 weeks provided successful tissue integration with high predictability , and that successful tissue integration was well maintained up to 3 years of follow-up in this study population BACKGROUND The aim of this study was to evaluate the clinical and radiographic changes in the peri-implant tissues around  one-stage implants  with different smooth neck portion lengths before and after functional prosthetic loading . METHODS Twelve one-stage implants were placed in adult patients with bilateral edentulous posterior m and ibular ridges . The sites were r and omly assigned into two groups of six each : group 1 : 2.8 mm neck implants and group 2 : neck implants . The parameters plaque index ( PI ) , gingival index ( GI ) , probing depth ( PD ) , gingival margin level ( GML ) , relative clinical attachment level ( r-CAL ) , and optical density ( OD ) were measured at loading ( 4 months ) and 12 months after implant placement . The radiographic parameter osseous level ( OL ) was measured at implant placement , loading , and at 12 months . Analysis of variance and the paired Student t test were used to detect difference over time and between groups . RESULTS The results showed significant differences ( P<0.05 ) for both groups for PD , r-CAL , and OL for intragroup comparisons over time . However , no significant differences were found for PI , GI , PD , GML , OD , and OL for between-group comparisons . CONCLUSION Bony loss occurred before loading , supporting the soft tissues and maintaining the biologic width irrespective of the smooth portion length The aim of this study of the present experiment was to study the marginal periimplant tissues at intentionally non-submerged ( 1-stage implants ) and initially submerged and subsequently exposed implants ( 2-stage implants ) . 5 beagle dogs , about 1-year-old , were used , 3 months after the extraction of the m and ibular premolars , fixtures of the Astra Tech Implants Dental System , the Brånemark System and the Bonefit -- ITI system were installed . In each m and ibular quadrant , 1 fixture of each implant system was installed in a r and omised order . The installation procedure followed the recommendations given in the manuals for each system . Thus , following installation , the bone crest coincided with the fixture margin of the Astra Tech Implants Dental System and the Brånemark System , whereas the border between the plasma sprayed and the machined surface of the Bonefit-ITI implant system was positioned at the level of the bone crest . Following a healing period of 3 months , abutment connection was carried out in the 2-stage systems ( the Astra Tech Implants Dental System and the Brånemark system ) . A 6-month period of plaque control was initiated . The animals were sacrificed and biopsies representing each important region dissected . The tissue sample s were prepared for light microscopy and exposed to histometric and morphometric measurements . The mucosal barrier which formed to the titanium surface following 1-stage and 2-stage implant installations comprised an epithelial and a connective tissue component , which for that 3 systems studied , had similar dimensions and composition . The amount of lamellar bone contained in the periimplant region close to the fixture part of the 3-implant systems was almost identical . It is suggested that correctly performed implant installation may ensure proper conditions for both and hard tissue healing , and that the geometry of the titanium implant seems to be of limited importance OBJECTIVES The aim of this prospect i ve cohort study was to evaluate the success rate of titanium screw-type implants with the s and blasted and acid-etched ( SLA ) surface loaded early , after 6 weeks of healing . MATERIAL AND METHODS A total of 104 implants were inserted into posterior sites of 51 partially edentulous patients exhibiting bone densities of class I-III . After a healing period of 6 weeks , all implants were functionally loaded with cemented crowns or fixed partial dentures . The patients were recalled at 3 , 12 , 24 , 36 , 48 and 60 months for clinical and radiographic examination . RESULTS One implant failed to integrate during healing , and three implants were lost to follow-up and were considered drop-outs . The remaining 100 implants showed favorable clinical and radiographic findings at the 5-year examination . The peri-implant soft tissues were stable over time ; the mean probing depths and mean attachment levels did not change during the follow-up period . None of the radiographs exhibited signs of continuous peri-implant radiolucency , which confirmed ankylotic stability for all 100 implants . The measurement of the bone crest levels ( DIB values ) indicated stability as well . Based on strict success criteria , all 100 implants were considered successfully integrated , result ing in a 5-year success rate of 99 % . CONCLUSION This prospect i ve study using an early loading protocol with 6 weeks of healing demonstrated that titanium implants with the SLA surface can achieve and maintain successful tissue integration with high predictability for at least 5 years of follow-up in selected patients and sites OBJECTIVES To investigate ( i ) the impact of different  titanium implant surfaces  on soft tissue integration over 6 months , and ( ii ) the influence of frequent clinical probing during the healing phase on the established mucosal seal . MATERIAL AND METHODS St and ardized clinical probing was r and omly performed ( 12 dogs , probing versus control ) at different transmucosal surfaces [ machined ( M ) , s and -blasted/acid-etched ( SLA ) , and chemically modified acid-etched ( modA ) , modSLA ] at 2 , 4 , 8 , and 12 weeks ( i.e. 1 x , 2 x , 3 x , and 4 x ) . Histomorphometrical analysis ( e.g. mucosal margin ( PM ) - apical extension of the junctional epithelium ( aJE ) , PM - coronal level of bone-to-implant contact ( CBI ) was performed at 4 , 8 , 12 , and 24 weeks . RESULTS While M and SLA groups revealed a split formation , epithelial cells and connective tissue were in close contact to modA and modSLA surfaces . Frequent clinical probing ( i.e. 3 x and 4 x ) increased mean pocket depths , PM-aJE , and aJE-CBI values in all groups and markedly disrupted the epithelial and connective tissue attachment . CONCLUSIONS It was concluded that irrespective of the surface characteristics , a frequent clinical probing at short intervals during the healing phase was associated with dimensional and structural changes of the mucosal seal OBJECTIVES The objective of this systematic review was to critically evaluate marginal soft-tissue aspects at implants subjected to immediate loading or immediate restoration . METHODS An electronic Medline search from 1966 up to August 2005 was conducted to identify prospect i ve and retrospective studies on immediate implant loading . The search strategy was complemented by h and search ing in peer- review ed journals . Studies reporting on soft-tissue aspects at implants subjected to immediate loading or immediate restoration and with a follow-up time of at least 1 year were included . Assessment of identified studies and data extraction was performed independently by two review ers . An attempt was made to isolate and categorize studies with similar protocol s in order to identify trends and relevant factors . Variables that were considered included marginal and interproximal soft-tissue stability , marginal plaque accumulation , probing depth , bleeding on probing , peri-implant mucositis and peri-implantitis . RESULTS From an initial yield of 581 titles , 240 articles were selected for text analysis , finally result ing in 17 studies that met the inclusion criteria . Six studies on immediate implant loading or restoration were controlled studies , whereas the remainder was prospect i ve case series . Seven studies reported on a 1-year data , and the longest follow-up within the included studies was 4 years . The total number of patients treated within the 17 studies was 432 including a total 706 implants studied . Overall , the articles reported on many different procedures and follow-up times , time points and evaluated soft-tissue parameters varied considerably between the different articles . CONCLUSION Within the limits of the evaluated data it can be cautiously concluded that once immediately loaded or restored implants integrate successfully , they appear to show a soft-tissue reaction with regard to periodontal as well as morphologic aspects comparable with those of conventionally loaded implants . However , follow-up periods are generally short , number of patients and /or implants per study are few , and most studies present only limited data on peri-implant soft-tissue evaluation . More accurate long-term studies with a stronger study design ( i.e. , RCT ) reporting more detailed on treatment and follow-up protocol s are required to allow for proper comparisons and conclusions PURPOSE The purpose of this prospect i ve clinical study was to compare titanium and gold-alloy abutments when used with cemented , implant-supported single-tooth crowns . For 4 years following prosthodontic rehabilitation , these abutments were evaluated with respect to peri-implant marginal bone levels and peri-implant soft tissue parameters . MATERIAL S AND METHODS During the years 1998 to 2000 , 20 patients were selected from a patient population receiving treatment in the Implantology Department at the University of Padova , Italy . They all presented with single-tooth bilateral edentulous sites in the premolar/molar region with adequate bone width , similar bone height on each side , and an occlusal scheme that allowed for the establishment of identical occlusal cusp/fossa contacts on each side . Each subject received two identical implants ( one in each edentulous site ) . One was r and omly selected to be restored with a titanium abutment and a cemented implant-supported single-tooth crown , and the other was restored with a gold-alloy abutment and a cemented implant-supported single tooth crown . Data on peri-implant marginal bone levels and soft tissue parameters were collected for 4 years after abutment and crown insertion placement and analyzed to determine whether there was a significant ( p < .001 ) difference with respect to the type of abutments ( titanium vs. gold alloy ) used . RESULTS All subjects completed the study . All 40 implants survived , result ing in a cumulative implant success rate of 100 % . Statistical analysis revealed no significant differences between the two groups with respect to peri-implant marginal bone levels and soft tissue parameters . CONCLUSIONS Within the limitations of this study , the results indicate that there was no evidence of different response with the peri-implant marginal bone and soft tissue when titanium or gold-alloy abutments were used in conjunction with the cemented , single-tooth implant restorations provided for this limited patient population . There was no evidence of different behavior of peri-implant marginal bone and of peri-implant soft tissue when titanium abutments or gold-alloy abutments were used for cemented single-tooth implant restorations in this limited patient population PURPOSE The aim of this prospect i ve cohort study was to determine the 5-year implant survival and success rates associated with early loading ( 6 weeks after nonsubmerged placement ) of s and blasted and acid-etched ( SLA ) Straumann implants in the edentulous m and ible . A secondary objective was to determine the peri-implant tissue response and measure alterations in peri-implant crestal bone levels . MATERIAL S AND METHODS SLA implants were placed and primarily loaded 6 weeks later with 35 Ncm during abutment placement . The peri-implant bone and mucosal conditions of the participants were monitored radiographically and clinical ly over a 5-year period . RESULTS Fourteen patients received 60 implants . Thirteen patients and 54 implants were examined at the 5-year appointment . Two of 60 implants failed during the healing period , and four implants were lost during follow-up and considered as dropouts . The remaining implants showed favorable clinical and radiographic findings and were considered successfully integrated at the 5-year examination . The mean loss of crestal bone height after 5 years was 0.77 mm ( SEM 0.09 ) . This result ed in a 5-year cumulative success rate of 96.7 % . CONCLUSION In this prospect i ve study , the early loading of  Straumann implants with the SLA surface in the edentulous m and ible after a healing time of 6 weeks provided successful osseointegration with high predictability . Successful integration was maintained for 5 years PURPOSE This prospect i ve , longitudinal study evaluated the survival , marginal bone levels , and soft tissue conditions for immediately loaded , straight-walled , platform-switched , titanium-alloy implants with an internal connection and nanosurface topography . MATERIAL S AND METHODS Patients were enrolled at a single center . The immediate loading protocol required a final insertion torque ≥ 25 Ncm , an implant stability quotient ( ISQ ) > 55 , and placement of the provisional prosthesis on the same day as implant placement . Posttreatment follow-up examinations were scheduled at 3 , 6 , and 12 months and annually thereafter . Soft tissue evaluation consisted of assessment of the implant sites for signs of peri-implant infection including mucosal inflammation , bleeding on probing or suppuration , and progressive bone loss . Oral hygiene was evaluated , and radiographic marginal bone levels were analyzed and compared to baseline at the time of provisional loading . RESULTS Forty-eight consecutively treated patients received 122 implants ; 112 qualified for immediate loading and were included . ISQ scores ranged from 51 to 87 , with a mean value of 75.1 ( SD = 6.8 ) . One implant failed ( after 3 months ) . After an average follow-up period of 6.2 years ( SD = 0.37 ; range , 5.4 to 6.9 ) , no further losses occurred , leading to an overall cumulative survival rate of 99.1 % . Average bone loss for the 111 implants after 6 years was 0.35 mm ( SD = 0.45 ; range : -0.35 to 2.20 ) . Four implants ( 3.6 % ) in two patients showed concomitant peri-implant infections associated with bleeding on probing and /or purulence after 2 years in function . Exploratory surgery revealed residual submucosal cement . After its removal , the progressive bone loss stopped , and peri-implant tissue in both patients returned to a healthy condition . CONCLUSION This study based on 40 patients treated with 112 straight-walled , platform-switched , titanium-alloy implants with nanosurface topography yielded a 99.1 % survival rate after a mean follow-up time of 6.2 years . Additionally , mean crestal bone loss was limited to 0.26 mm ( SD = 0.38 ) after 1 year and 0.35 mm ( SD = 0.45 ) after 6 years . Peri-implant infection associated with excessive bone loss above 2 mm was only encountered in one implant , and residual cement was shown to be responsible PURPOSE The aim of this longitudinal study was to gain 5-year clinical documentation of the 1-stage surgical technique in connection with ITI solid-screw implants used in the edentulous m and ible . MATERIAL S AND METHODS One hundred patients with totally edentulous m and ibles were treated with bar-retained overdentures supported by a total of 340 consecutively placed ITI solid-screw implants . The patients were followed at annual intervals for at least 5 years to evaluate implant success , longitudinal reactions of the peri-implant hard and soft tissues , and incidences of biologic and mechanical complications . RESULTS During the trial period , a total of 4 implants failed , all prior to loading , and 51 implants were lost to follow-up , result ing in a cumulative survival rate of 98.8 % after 5 years of functional service . The success analysis included additional strictly defined events ( either " first occurrence of marginal bone loss > or = 4 mm " or " first occurrence of pocket depth > or = 4 mm " and " first occurrence of crevicular fluid flow rate > or = 2.5 mm ) and result ed in a cumulative 5-year success rate of 95.7 % . The median marginal bone loss experienced between implant placement and prosthetic treatment was 0.5 mm , followed by an annual bone level change of 0.1 mm for the functional period of 5 years . The increasing incidence of remarkable plaque deposits from 19 % to 50 % represented the difficulties of the patients in maintaining a high level of oral hygiene , particularly for the lingual surfaces . Sulcus Bleeding Index , probing depth , attachment level , and crevicular fluid flow rate were used to describe the health of the peri-implant soft tissues and remained almost within acceptable st and ards . DISCUSSION Survival and success rates of implants , amount of marginal bone loss , and periodontal indices of peri-implant soft tissues were consistent with those reported in the literature regarding implants with the submerged healing concept . CONCLUSION With a cumulative survival rate of 98.8 % , a cumulative success rate of 95.7 % , and a median marginal bone loss of 0.5 mm during the healing period , followed by an annual rate of 0.1 mm after loading , non-submerged ITI solid-screw implants confirm the good clinical outcome of implant-supported treatment concepts for the rehabilitation of totally edentulous patients in a medium-term perspective AIM To evaluate the 10-year post-loading radiological and esthetic outcomes of  implants inserted in post- extraction sites and restored with or without platform-switching protocol . MATERIAL AND METHODS Twenty-two patients were scheduled for maxillary post-extractive implant , using a 13 mm in length and 5.5 mm in diameter implant ( Global , Sweden & Martina , Padua , Italy ) . They r and omly received definitive restorations using platform-switching concept ( abutment 3.8 mm in diameter : test group ) or st and ard restoration ( abutment 5.5 mm in diameter : control group ) . Outcome measures were survival rates of implants and prostheses , peri-implant marginal bone loss and periodontal indices 10 years after prosthetic loading . Moreover , esthetic parameters including soft tissue buccal peri-implant mucosal levels ( REC ) and mesial and distal papilla height ( PH ) were taken at definitive restoration , 2 and 10 years thereafter . RESULTS Nineteen implants were analyzed after 10 years of follow-up . No implants nor prostheses failed . The postoperative radiographs demonstrated an overall mean bone loss of 0.18 ± 0.14 mm in the test group and of 0.80 ± 0.40 mm in the control group ( P = 0.00108 ) . Test group showed 0.23 ± 0.51 mm of REC gain and PH was of 0.21 ± 0.33 mm on average . On the other side , the control group presented a REC = -0.59 ± 0.80 mm with PH = -1.12 ± 0.55 mm , demonstrating a slight continuous soft tissue shrinkage during the entire follow-up . The mean values were statistically significant different between test and control group for both REC gain ( P = 0.01174 ) and PH ( P = 0.0009 ) . CONCLUSIONS With the limitations of this study , immediate single implant restorations rehabilitated with platform-switching protocol may provide peri-implant alveolar bone-level stability and avoid continuous soft tissue shrinkage after 10 years of prosthetic loading compared to a platform-matching restoration . Further studies involving larger sample sizes are required to confirm these preliminary results PURPOSE The aim of this clinical research on implant-supported restorations is to analyze , through spectrophotometric digital technology , the influence of the abutment material on the color of the peri-implant soft tissue . MATERIAL AND METHODS Twenty patients received an endosseous dental implant in the anterior maxilla . At the time of each definitive prosthesis delivery , an all-ceramic crown has been tried on gold , titanium and zirconia abutment . After the insertion of each single abutment , the peri-implant soft tissue color has been measured through a spectrophotometer . Also , the thickness of the facial peri-implant soft tissue was measured at the level of the implant neck through a caliper . A specific software has been utilized to identify a specific tissue area and to collect the data before the statistical analysis in Lab * color space . The normality of the quantitative variables was verified by means of the Shapiro-Wilk test . Simple linear correlation between quantitative variables was evaluated by using Pearson 's coefficient . The results on the performance of the abutment material s with regard to the color measurements and the overall measurement ΔE were described by computing the least-square means . The significance of differences among types of abutment was verified by means of the Scheffe test for multiple comparisons . RESULTS For all the abutments used , the color of the peri-implant soft tissue appeared to be significantly different from the one of the contra-lateral tooth ( ΔE>8.5 ) . Significantly higher ( P<0.05 ) difference were present with the use of titanium abutments ( 11 ± 0.4 ) when compared with the results of gold ( 8.9 ± 0.4 ) and zirconia ( 8.5 ± 0.4 ) abutments . No correlation has been demonstrated between soft tissue thickness and degree of color difference ( P>0.25 ) . CONCLUSIONS Within the limitation of the present study , the peri-implant soft tissue color appears to be different from the soft tissue color around natural teeth , no matter which type of restorative material is selected . When titanium abutment was selected , significantly higher differences were present than those obtained with gold or zirconia abutments . The thickness of the peri-implant soft tissue did not appear to be a crucial factor in the abutment impact on the soft tissue color 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 AIM To compare the health of the soft tissues towards  zirconia and titanium abutments in man , as observed using histological data . MATERIAL AND METHODS Twenty patients received two m and ibular implants with either a zirconia or titanium abutment ( split mouth study design , left-right r and omization ) . After 3 months soft tissue biopsies were prepared for histological evaluation . They were subjected to blind evaluation . The number of blood vessels per surface unit and an inflammation grading scale score ranging from 1 to 4 were determined . RESULTS Paired sample s from 17 patients were suitable for analysis , 3 with unsevered implant-abutment connections and 14 solely containing soft tissue . All showed a well-keratinized stratified squamous epithelium which was continuous with the barrier ( junctional ) epithelium that faced the abutment surface . The normal epithelial build-up could be recognized with little signs of inflammation . No statistically significant difference in tissues adjacent to zirconia and titanium abutment surfaces were seen with respect to vascular density ( 20.5 SD 4.4 and 20.7 SD 3.2 ) or inflammation grading scale scores ( 3.2 SD 0.7 versus 3.1 SD 0.7 ) . CONCLUSION No differences in soft tissue health were seen in peri-implant mucosa adjacent to zirconia and titanium abutment surfaces PURPOSE Several long-term clinical studies have shown a mean marginal bone loss around dental implants of 1.5 to 2 mm in the first year after prosthetic restoration . Currently , concepts to avoid bone remodeling around dental implants have been developed . The use of prosthetic abutments with reduced width in relation to the implant diameter ( platform switching ) seems to have the greatest potential to limit the crestal resorption . The purpose of this clinical trial was to show that crestal bone height around dental implants  could be influenced using a platform switch protocol and that the bone level would remain stable within 1 year after final prosthetic reconstruction . MATERIAL S AND METHODS Fifteen patients were treated with fixed implant retained prosthesis ; 14  wide-diameter implants were supplied with platform-switched abutments and served as the test group . Eight implants with regular diameter were reconstructed with traditional abutments and served as the control group . St and ardized digital radiographs were obtained for evaluation of the peri-implant bone levels at the time of installation of the final restoration and at 1-year follow-up . Marginal peri-implant bone levels were measured at the mesial and distal surfaces of each implant using digital image analysis . RESULTS The mean values of crestal bone height at baseline were -0.09 mm + /- 0.65 mm for the platform-switched implants and -1.73 mm + /- 0.46 mm for the nonplatform-switched implants . One year after final restoration , the mean value of crestal bone height was -0.22 mm + /- 0.53 mm for the test group and -2.02 mm + /- 0.49 mm for the control group . When tested with statistical means , the differences were significant for baseline and for follow-up ( P < /= .0001 ) . Mean bone level change from baseline to 1-year follow-up was -0.12 mm + /- 0.40 mm for the test group and -0.29 mm + /- 0.34 mm , respectively , for the control group . On analysis using ANCOVA , this difference was shown to be significant ( P < /= .0132 ) . CONCLUSION The concept of platform switching appears to limit crestal resorption and seems to preserve peri-implant bone levels . A certain amount of bone remodeling 1 year after final reconstruction occurs , but significant differences concerning the peri-implant bone height compared with the nonplatform-switched abutments are still evident 1 year after final restoration . The reduction of the abutment of 0.45 mm on each side ( 5 mm implant/4.1 mm abutment ) seems sufficient to avoid peri-implant bone loss
Evidence analysis shows that the present knowledge about biologic width around implants is mainly derived from animal studies and that clinical controlled human studies are insufficient
PURPOSE The concept of biologic width forms a basis for successful peri-implant soft tissue integration around titanium implants .
Therefore , the objectives of this review are to determine and critically evaluate the present knowledge about biologic width around implants and to establish future research trends .