Peri-implant Bone Level Changes Research Articles

Peri‐implant soft tissue and bone crest alterations at fixed dental prostheses: a 3‐year prospective study

The aim of this 3-year prospective study involving patients receiving implant-supported fixed dental prostheses (FDPs) was to longitudinally evaluate soft and hard tissue alterations from the time of implant placement. Sixteen subjects with 18 implant-supported FDPs on 43 implants were included in the study. Peri-implant soft and hard tissue assessments were performed at implant placement, 2, 6, 12, 24 and 36 months. Variables describing the peri-implant soft tissue conditions and topography were assessed by clinical, photographic and study model assessments. Variables of implant position and bone topography were measured in radiographs taken at each examination interval. Multilevel regression models were formulated to identify factors of significance for proximal bone crest alterations and proximal soft tissue height. During the first 6 months after the one-stage implant placement surgery, the soft tissue margin receded about 0.6 mm at facial implant sites, while a mean increase was observed at tooth-facing proximal sites (1.1 mm) and no change at inter-implant sites. Loss in proximal bone crest height was more pronounced at inter-implant than tooth-implant units at 6 months (0.6 vs. 0.1 mm). Between 6 and 36 months, no further significant soft or hard tissue changes were observed. Multilevel regression analysis revealed that the proximal bone crest level significantly influenced the proximal soft tissue height assessed from the implant/abutment level. Significant predictors for loss in proximal bone crest level over the 3 years were horizontal inter-unit distance, type of proximal unit (tooth/implant or inter-implant) and peri-implant bone-level change. Soft and hard tissue changes around implant-supported FDPs took place primarily during the first 6 months after the one-stage implant installation surgery. The pattern of tissue alterations during the follow-up differed between tooth-implant and inter-implant proximal sites.

X-ray evaluation at 5–6 years of Straumann implants (part 2)

Long term preservation of crestal bone height around osseointegrated implants is often used as a measure of primary success [5, 12, 22]. Prospective long-term studies exhibited survival and success rates largely exceeding 95% after 5 and 10 years of follow-up for the Straumann R © implant system [3, 5, 18, 22, 45, 57]. A mean crestal bone loss ≤1.5 mm during the first year and ≤ 0.2 mm per year thereafter is proposed as one of the major success criteria. If we apply these strict success criteria then the CBL in 5 years should not exceed 2.3 mm [1.5 + (0.2 × 4)]. In the current study, 8.5% of the implants exhibited “supra-boundary bone”. In addition to 84.5% of the implants showing bone loss within the physiological range (0–3 mm), giving an overall successful pool of implants up to 93%. This represents a high success rate considering the private practice setting and the absence of exclusion criteria in the initial enrolment of the patients. Patients with implants exhibiting a bone loss of 2–3 mm (7.8%) would require careful monitoring, with closer hygiene recalls and increased education in regard to patient awareness for dental hygiene and maintenance. Bone loss greater than 3 mm was observed in 7% of the included implants. At the 5-6 year control, they were still well integrated in the jaw bone and the subjects did not manifest any symptoms that previously identified them as unsuccessful [7]. Moreover, the status and prognosis of such implants have to be carefully interpreted because other factors, mainly clinical parameters such as bleeding on probing and pocket depths, were not available, in contrary to previous studies [5, 12, 31, 38, 39, 45–47, 51]. Considering such arguments, and although these implants were put by the study group in the unsuccessful implants category, one could argue the contrary. This group deserves careful monitoring, with closer hygiene recalls, more follow-up radiographs, and extended patient awareness to dental hygiene. For the Straumann R © implants, the distance from the implant shoulder to the first bone–implant contact was called DIB (distance implant-bone) and was used in previous studies [16, 21]. These studies followed the changes in periimplant bone levels over time by taking measurement between two time points. A baseline and a postoperative radiograph were usually taken to identify initial and final bone levels, and therefore to calculate the difference: Δ DIB. In the present study, an original method was used to calculate the bone change: the interface of the smoothroughened surface (identified as the R interface) was considered as the baseline level. It was assumed to be the level up to which bone loss was considered as physiological, i.e. not affected by external factors. Bone loss occurring further from this point, in an apical implant direction, was thus identified as crestal bone loss (CBL). Bone localized coronally to this interface was defined as “supra-boundary bone”. When the bone level was stabilized at the interface, it was then considered that no bone change occurred (CBL and “supra-boundary bone” were equal to 0 mm). From that point, it was interesting to identify factors that might enhance bone loss or favor bone maintenance when single-staged Straumann R © implants with treated TPS/SLA surfaces were used. It could be argued that the mean CBL was even lower than the 1.2 mm obtained in this study, as this value was compensated with implants that had what was called “supra-boundary bone”. The present study did not quantify this “supra-boundary bone”, as was described in a recently published study [51]. A paralleling radiographical technique may sometimes be difficult to perform because of the implant inclination and patient anatomy. For example, in the case of an extremely resorbed mandible, the intra-oral placement of the film was impossible because of the interference of the mouth floor [33]. In the maxilla, where the palate is the most inclined, it was difficult to position the film without bending [34]. This explained the large number of un-interpretable radiographs in these two regions. When observing the comparative tables for the statistically significant results, namely surface texture, smoking status, anterior/posterior location and VBL, it is worth noticing

Early Survival of Single-Tooth Implants in the Esthetic Zone may be Predictable Despite Timing of Implant Placement or Loading

The authors used MEDLINE, EMBASE, and CENTRAL (Cochrane Central Register of Controlled Trials) databases to locate studies for this systematic review (SR). For studies to be eligible for this SR, all had to evaluate single-implant restorations with a follow-up of at least 1 year after implant loading. A total of 19 prospective studies met inclusion and exclusion criteria. Fifteen studies provided implant survival data (499 patient/509 implants), whereas 5 studies provided radiographic marginal bone height data (52 patients/52 implants). The analysis included studies with patients with single anterior or premolar,maxillary or mandibular edentulous sites bounded by anterior and posterior neighboring teeth. Meta-analyses of prospective trials (randomized-controlled trials, clinical trials, cohort studies, case series) reported loaded implant survival with one-year or more than one-year follow-up. Meta-analysis of prospective trials reporting marginal bone loss with one-year follow-up was also reported. The key interventions were the timing of implant placement following extraction and the timing of implant loading after implant placement. Comparisons following greater than one-year follow-up were made between implants with immediate placement with immediate loading, immediate/early placement with conventional loading, conventional placement with immediate/early loading, or conventional placement with conventional loading. The main outcome was implant survival. Radiographically determined peri-implant bone level change was also reported. Meta-analyses were completed using studies that reported one-year implant survival data (15 studies) and more than one-year implant survival data (11 studies). One-year marginal bone level data were analyzed for implants treated conventionally (5 studies). For survival and marginal bone levels, weighted rates and random effects models were used to calculate overall effects of the included studies. For greater than one-year follow-up, survival data were stratified by intervention type. Results were weighted for study size and stratified based upon timing of implant placement and loading. Esthetics, and patient satisfaction, and complications were reported, but heterogeneity of study design and reported outcomes excluded the results from meta-analysis. Approximately two-thirds of patients received implants in healed edentulous sites. Survival of single-tooth implants one year in function was 95.5% [95% CI: 93.0-97.1]. Meta-analysis identified no difference in survival rate at one year when the results were weighted for study size and stratified based upon timing of implant placement and loading. Survival of single-tooth implants more than one year in function ranged from 92.4% [95% CI: 84.4-96.4] for conventional placement with immediate loading to 97.5% [95% CI: 88.3-99.5] for immediate placement with immediate loading. The third meta-analysis identified 0.20-mm [95% CI:0.034-0.36] marginal bone loss for implants one year in function. Qualitative interpretation of other esthetic, patient satisfaction, and complication outcomes revealed no difference in immediate, early, or conventional therapy approaches. The authors concluded that implant-supported single-tooth replacement in the aesthetic zone with adjacent natural teeth can lead to short-term, favorable outcomes with regard to implant survival and marginal bone level change with early/immediate or conventional surgical placement and loading strategies.

Survival and complication rates of implant‐supported fixed partial dentures with cantilevers: a systematic review

The objective of the present systematic review was to analyze the potential effect of incorporation of cantilever extensions on the survival rate of implant-supported fixed partial dental prostheses (FPDPs) and the incidence of technical and biological complications, as reported in longitudinal studies with at least 5 years of follow-up. A MEDLINE search was conducted up to and including November 2008 for longitudinal studies with a mean follow-up period of at least 5 years. Two reviewers performed screening and data abstraction independently. Prosthesis-based data on survival/failure rate, technical complications (prosthesis-related problems, implant loss) and biological complications (marginal bone loss) were analyzed. The search provided 103 titles with abstract. Full-text analysis was performed of 12 articles, out of which three were finally included. Two of the studies had a prospective or retrospective case-control design, whereas the third was a prospective cohort study. The 5-year survival rate of cantilever FPDPs varied between 89.9% and 92.7% (weighted mean 91.9%), with implant fracture as the main cause for failures. The corresponding survival rate for FPDPs without cantilever extensions was 96.3-96.2% (weighted mean 95.8%). Technical complications related to the supra-constructions in the three included studies were reported to occur at a frequency of 13-26% (weighted mean 20.3%) for cantilever FPDPs compared with 0-12% (9.7%) for non-cantilever FPDPs. The most common complications were minor porcelain fractures and bridge-screw loosening. For cantilever FPDPs, the 5-year event-free survival rate varied between 66.7% and 79.2% (weighted mean 71.7%) and between 83.1% and 96.3% (weighted mean 85.9%) for non-cantilever FPDPs. No statistically significant differences were reported with regard to peri-implant bone-level change between the two prosthetic groups, either at the prosthesis or at the implant level. Data on implant-supported FPDPs with cantilever extensions are limited and therefore survival and complication rates should be interpreted with caution. The incorporation of cantilevers into implant-borne prostheses may be associated with a higher incidence of minor technical complications.

Bone level changes at implants supporting crowns or fixed partial dentures with or without cantilevers

The aim of this study was to analyze whether or not a cantilever extension on a fixed dental prosthesis (FDP) supported by implants increased the amount of peri-implant bone loss or technical complications compared with reconstructions without cantilevers. Fifty-four partially dentate patients with a total of 54 FDPs supported by 78 implants were enrolled in the study. Twenty-seven FDPs were with cantilever and 27 FDPs were without cantilever (control group). All FDPs were supported by one or two implants and were located in the posterior maxilla or mandible. The primary outcome variable was change in peri-implant marginal bone level from the time of FDP placement to the last follow-up visit. FDPs were under functional loading for a period of 3 up to 12.7 years. Statistical analysis was carried out with Student's t-test. Regression analyses were carried out to evaluate the influence of confounding factors on the peri-implant bone level change. In addition, implant survival rates were calculated and technical complications assessed. After a mean observation period of 5.3 years, the mean peri-implant bone loss for the FDPs with cantilevers was 0.23 mm (SD+/-0.63 mm) and 0.09 mm (SD+/-0.43 mm) for FDPs without cantilever. Concerning the bone level change at implants supporting FDPs with or without cantilevers no statistically significant differences were found. The regression analysis revealed that jaw of implant placement had a statistically significant influence on peri-implant bone loss. When the bone loss in the cantilever group and the control group were compared within the maxilla or mandible separately, no statistically significant difference was found. Implant survival rates reached 95.7% for implants supporting cantilever prostheses and 96.9% for implants of the control group. Five FDPs in the cantilever group showed minor technical complications, none were observed in the control group. Within the limitations of this study it was concluded that cantilever on FDPs did not lead to a higher implant failure rate and did not lead to more bone loss around supporting implants compared with implants supporting conventional FDPs. In contrast to these results more technical complications were observed in the group reconstructed with cantilever.

Immediate non‐occlusal vs. early loading of dental implants in partially edentulous patients: a multicentre randomized clinical trial. Peri‐implant bone and soft‐tissue levels

To compare peri-implant bone and soft-tissue levels of immediately non-occlusally loaded vs. non-submerged early loaded implants in partially edentulous patients up to 14 months after placement. Fifty-two patients were randomized in five Italian private practices: 25 in the immediately loaded group and 27 in the early loaded group. To be immediately loaded, single implants had to be inserted with a torque of > or = 30 N cm, and splinted implants with a torque of > or = 20 N cm. Immediately loaded implants were provided with non-occluding temporary restorations within 48 h. After 2 months, the provisional restorations were placed in full occlusion. Implants were early loaded after 2 months. Final restorations were provided 8 months after placement. Blinded assessors evaluated peri-implant bone and soft-tissue levels. Fifty-two implants were immediately loaded and 52 were early loaded. No drop-out occurred. One single immediately loaded implant failed 2 months after placement. Both groups gradually lost peri-implant bone in a highly statistically significant manner at 2, 8, and 14 months. After 14 months, patients of both groups lost an average of 1.1 mm of peri-implant bone. There were no statistically significant differences between the two loading strategies for peri-implant bone and soft-tissue level changes (P > 0.05). After 14 months, the position of the soft tissues did not change significantly from baseline (delivery of the final restorations 8 months after placement). There were no statistically or clinically significant differences between immediate and early loading of dental implants with regard to peri-implant bone and soft-tissue levels as evaluated in the present study.

Bone level alterations at implants placed in the posterior segments of the dentition: outcome of submerged/non‐submerged healing. A 5‐year multicenter, randomized, controlled clinical trial

To determine if longitudinal bone level change at Astra Tech implants placed in the posterior part of the dentition was influenced by the healing conditions provided following implant placement, i.e., submerged or non-submerged healing. Eighty-four patients and 115 fixed partial dentures (FPDs or cases) entered the study. The cases were randomized into two implant installation groups: initially non-submerged (group A) or initially submerged (group B) implants. Three hundred and twenty-four implants were installed (group A=153; group B=171): 145 in the maxilla and 179 in the mandible. Radiographs from the implant sites were obtained at FPD insertion (baseline) and subsequently every 12 months. In the radiographs, the position of the marginal bone at the mesial and distal aspects of the implants was determined and the radiographic (Rx) bone level change over time was calculated. Seven implants failed to integrate (four in group A and three in group B). During the 5 years of monitoring, three implants had to be removed and 35 implants were lost to follow-up. The Rx bone level alteration that occurred during year 1 was 0.02+/-0.38 mm in group A and 0.17+/-0.51 mm in group B. During the subsequent 4 years there was some further Rx bone loss in group B (0.02+/-0.62 mm), while in group A there was some gain of bone (0.07+/-0.5 mm). The peri-implant bone level change and number of biological complications that took place during the 5 years was small and unrelated to the surgical protocol used for implant placement.

Bone level changes at axial‐ and non‐axial‐positioned implants supporting fixed partial dentures. A 5‐year retrospective longitudinal study

The aim of this study was to retrospectively analyze the potential influence of implant inclination on marginal bone loss at freestanding, implant-supported, fixed partial dentures (FPDs) over a 5-year period of functional loading. The material comprised 38 periodontally treated, partially dentate patients with a total of 42 free-standing FPDs supported by implants of the Astra Tech System. Mesio-distal inclination of the implants in relation to a vertical axis perpendicular to the occlusal plane was measured with a protractor on standardized photographs of the master cast. The two tail quartiles of the distribution of the implants with regard to the implant inclination were defined as axial-positioned (mean 2.4 degrees; range 0-4 degrees) and non-axial-positioned implants (mean 17.1 degrees; range 11-30 degrees), respectively. For FPDs supported by two implants, both the mesial-distal and buccal-lingual inter-implant inclination was measured. The primary outcome variable was change in peri-implant bone level from the time of FPD placement to the 5-year follow-up examination. Comparison between axial- and non-axial-positioned implants was performed by the use of a Mann-Whitney U-test. Spearman's correlation analysis was used to analyze relationships between inter-implant inclination (mesial-distal and buccal-lingual) and 5-year bone level change on the FPD level. The 5-year mean bone level change amounted to 0.4 mm (SD 0.97) for the axial and 0.5 mm (0.95) for non-axial-positioned implants (P>0.05). For the FPDs supported by two implants, the mean inter-implant inclination was 9.2 degrees (1-36 degrees) in the mesial-distal direction and 6.7 degrees (0-24 degrees) in the buccal-lingual direction. Correlation analysis revealed lack of statistically significant correlation between inter-implant inclination (mesial-distal and buccal-lingual) and 5-year bone level change (r=-0.19 and r=-0.32, respectively). The study failed to support the hypothesis that implant inclination has an effect on peri-implant bone loss.

Le Fort I osteotomy with interpositional bone grafts and delayed oral implants for the rehabilitation of extremely atrophied maxillae: a 1–9‐year clinical follow‐up study on humans

The purpose of this clinical follow-up study was to report the clinical outcome of osseointegrated implants placed in extremely atrophied edentulous maxillae after Le Fort I osteotomy and interpositional autogenous iliac bone grafts. In a 10-year period (1995-2004), 39 patients, 18 males and 21 females, aged from 32 to 76 years, presenting with severely atrophied edentulous maxillae were treated with Le Fort I osteotomy and interpositional iliac bone grafts. Four to 8 months after the reconstructive procedure, 281 osseointegrated implants were placed in the reconstructed maxillae. Four to 8 months afterwards, abutments were connected and the prosthetic rehabilitation started. The mean follow-up period of implants after the start of prosthetic loading was 45.9 months (range: 12-108 months). The reconstructive procedure was successful in 38 of 39 patients. In one patient, partial loss of the inlay graft occurred before implant placement. Six patients (42 implants) dropped out of the study. Fifteen implants were removed during the follow-up period, due to loss of integration. Thirty-two implants, although integrated, presented with peri-implant bone-level changes higher than those proposed for successful implants. Cumulative survival and success rates of implants were 94.5% and 82.9%, respectively. Results from this study showed that Le Fort I osteotomy with interpositional bone grafts followed by delayed implant placement is an acceptable means to rehabilitate edentulous patients affected by extremely atrophied edentulous maxillae. Survival rates of implants are consistent with those related to implants placed in native, non-reconstructed bone. Conversely, the success rate of implants resulted to be lower as compared with those obtained for implants placed in native bone.

Implant‐supported single‐tooth restorations: a 5‐year prospective study

Comparatively few studies are available reporting at least 5 years of follow-up data of implant-supported single-tooth replacements. To evaluate prospectively the 5-year outcome of implant-supported single-tooth prosthetic restorations. Forty subjects (mean age 41 years), 23 males and 17 females, who required single-tooth prosthetic replacement for a missing tooth were recruited. A total of 45 self-tapping implants (Astra Tech ST-implants)--40 in the maxilla and five in the mandible--were installed in a two-stage procedure. Abutment connection was performed 3-6 months after implant installation. Clinical and radiographic examinations were performed at the completion of the prosthetic treatment and once a year during a 5-year follow-up period. The analysis of peri-implant bone level alteration was performed on subject and implant levels and by the use of analysis of variance and binary logistic regression. Three patients were lost during the 5 years of follow-up. One implant was lost after 2.5 years in function and another four implants could not be accounted for at the 5-year follow-up examination. The overall failure rate at 5 years was 2.6% (subject level) and 2.3% (implant level). The mean loss of marginal bone at the implants during the first year in function was 0.06 mm (SD 0.67) on the subject level and 0.02 mm (0.65) on the implant level. During the subsequent 4 years the annual change in peri-implant bone level amounted to -0.02 mm (0.22) on both subject and implant levels. Thus, the mean total bone level change over the 5-year interval was -0.14 mm (1.04) on subject level and -0.11 mm (1.00) on the implant level of analysis (p>0.05). The frequency of implants with a 5-year bone loss of > or =1 mm was 13%. Approximately 50% of the implants demonstrated no bone loss. The present clinical trial on single-tooth replacements with the Astra Tech implant system demonstrated that the bone loss during the first year of function as well as annually thereafter was small.

Bone level change at implant‐supported fixed partial dentures with and without cantilever extension after 5 years in function

The aim of this study was to retrospectively analyze whether the inclusion of cantilever extensions increased the amount of marginal bone loss at free-standing, implant-supported, fixed partial dentures (FPDs) over a 5-year period of functional loading. The patient material comprised 45 periodontally treated, partially dentate patients with a total of 50 free-standing FPDs supported by implants of the Astra Tech System. Following FPD placement (baseline) the patients were enrolled in an individually designed supportive care program. A set of criteria was collected at baseline to characterize the FPDs. The primary outcome variable was change in peri-implant bone level from the time of FPD placement to the 5-year follow-up examination. The comparison between FPDs with and without cantilevers was performed at three levels: FPD level, implant level, and surface level. Bivariate analysis was performed by the use of the Mann-Whitney U-test and stepwise regression analysis was utilized to evaluate the potential influence of confounding factors on the change in peri-implant bone level. The overall mean marginal bone loss for the implant-supported FPDs after 5 years in function was 0.4 mm (SD, 0.76). The bone level change at FPDs placed in the maxilla was significantly greater than that for FPDs in the mandible (0.6 versus 0.2 mm; p<0.05). No statistically significant differences were found with regard to peri-implant bone level change over the 5 years between FPDs with and without cantilevers at any of the levels of comparisons. The multivariate analysis revealed that the variables jaw of treatment and smoking had a significant influence on peri-implant bone level change on the FPD level, but not on the implant or surface levels. The model explained only 10% of the observed variance in the bone level change. The study failed to demonstrate that the presence of cantilever extensions in an FPD had an effect on peri-implant bone loss.

Peri-implant bone alterations in relation to inter-unit distances. A 3-year retrospective study.

The aim of the present retrospective study was to evaluate longitudinal alterations in radiographic bone topography at proximal sites of three-unit implant-supported fixed partial prostheses during the first 3 years after bridge installation, in relation to vertical and horizontal inter-unit distances. The subjects were partially dentate patients who had received implant-supported fixed partial prostheses during the year 1995 at the Brånemark Clinic, Göteborg, Sweden. For inclusion in the study, the patient had to have a three-unit bridge construction supported by three implants in the posterior area of the jaw. Twenty-eight patients having 35 screw-retained prostheses on Brånemark standard implants fulfilled the inclusion criteria. Radiographs obtained at bridge installation and at 1- and 3-year follow-ups were assessed for implant positions, contact point level, bone level at implants and adjacent tooth and mid-proximal bone crest level. The data were analysed with respect to two proximal units: tooth/implant units (n=35) and implant/implant units (n=70). Multiple regression analyses were used to evaluate the influence of various factors on the peri-implant and periodontal bone level changes during the 3 years of follow-up. At the tooth/implant units, the mean bone loss over the 3 years was 0.5 mm at the implant and 0.4 mm at the tooth. Multiple regression analysis failed to identify significant explanatory factors for the peri-implant/periodontal bone level changes at the tooth/implant units (R2=0.28). At the implant/implant units, the peri-implant bone loss was 0.6-0.7 mm and was significantly influenced by the vertical inter-implant distance (P<0.01), the difference in bone level at baseline between two neighbouring implants (P<0.001) and the bone level changes at the opposed implant surface (P<0.001) (R2=0.49). Furthermore, the magnitude of apical displacement of the inter-implant bone crest level during the 3 years of follow-up was negatively associated with the horizontal inter-implant distance (P<0.05). The results of the study demonstrated that both vertical and horizontal differences in implant positions might influence bone alterations in the inter-implant area during the first 3 years of loading, while the data failed to show corresponding relationships for the bone changes at the proximal area between the implant and the neighbouring tooth.

IL-1 gene polymorphism and smoking as risk factors for peri-implant bone loss in a well-maintained population.

The aim of the present study was (i) to investigate the relation between specific interleukin-1 (IL-1) gene polymorphisms and peri-implant bone loss at osseointegrated ITI(R) dental implants and (ii) to explore the association between these allelic variants of the IL-1 gene complex and peri-implant mucosal inflammation, in both smoking and non-smoking individuals. A sample of 90 consecutive Caucasian patients (aged 33-88 years), treated with at least one ITI-implant participated in this retrospective investigation. Standardized periapical radiographs were taken after prosthetic rehabilitation (133.6 days, SD 136.9 days) and at the time of the re-examination, on average 5.6 years (SD 2.5 years) thereafter. The radiographs were analyzed by a calibrated examiner for changes in peri-implant bone levels. The examiner was blind with respect to clinical parameters and IL-1 status. The distance between the implant shoulder and the first visible bone-implant contact (DIB) at the respective time points were measured using a computerized method. The absolute bone level difference during the years of service (ABL) and the annual bone loss (DeltaBL/year) were calculated for all the implants. Percentages of full mouth bleeding on probing (BOP), as well as of BOP calculated separately for teeth and implants, were determined for all visits and averaged for the entire observation period. Out of the total patient sample, there were 14 heavy smokers (= 20 cigarettes/day), 14 moderate smokers (5-19 cigarettes/day), 23 previous smokers (smoking cessation > 5 years) and 39 non-smokers. Twenty-eight (31.11%) patients were IL-1 genotype positive. Upon stratification for smoking status, significant differences were found for the variables ABL (P < 0.04, U-test) and DeltaBL/year (P < 0.04, U-test) between non-smokers and heavy smokers for the IL-1 genotype positive group but not for the IL-1 genotype negative group. Moreover, significant differences in ABL (P < 0.04, U-test) and DeltaBL/year (P < 0.04, U-test) were identified between former smokers and heavy smokers for the IL-1 genotype positive group. The differences in inflammatory parameters (BOP) did not reach statistical significance. This study suggests that in heavy cigarette smokers, carriage of a functionally significant IL-1 gene complex polymorphism is associated with an increased risk for peri-implant bone loss following prosthetic reconstruction and during the supportive periodontal care phase of the treatment.

Free vascularized grafts in reconstruction of mandibular defects in war wounds

It can be difficult to achieve a natural appearance in the anterior region with implant-supported restorations because metal components may show through the soft tissue. Zirconia implants, therefore, should be considered as an alternative treatment for improved esthetics. The goal of this clinical report was to evaluate a new 2-piece zirconia implant system for the maxillary anterior region. A 2-piece zirconia dental implant was placed in the maxillary left lateral incisor position and left in place for 6 months to osseointegrate. Panoramic and periapical radiographs were examined for bone-implant osseointegration. The plaque control record (PCR), bleeding on probing (BOP), and probing depth (PD) were measured after the cementation of the definitive restoration and a 6-month follow-up period. The PCR, BOP, and PD values were compared and the marginal bone level was also evaluated by making standardized periapical radiographs. The results showed that over the 6-month follow-up period, the marginal area was healthy and presented no bleeding on probing, no plaque accumulation, and no change in periimplant marginal bone level.

Radiographic evaluation of crestal bone levels adjacent to nonsubmerged titanium implants.

Several parameters have been described to determine success or failure in long-term evaluations of dental implants. One of these parameters is the observation of changes in peri-implant bone levels. Studies on submerged implants have analyzed the bone level changes in the pre- and post-loading phases. No such data exist for intentionally nonsubmerged implants. The purposes of this study were: (1) to test the applicability and reproducibility of a simple computer-assisted method in the evaluation of changes in peri-implant bone levels; (2) to establish a baseline for the longterm radiographic follow-up; and (3) to evaluate changes in crestal bone levels adjacent to nonsubmerged ITI implants between the 1-year and 2-year examination. Standardized periapical radiographs were obtained from 80 implants at the 1-year and 2-year follow-up examinations after their placement. The implants were located in different jaw areas of 55 patients and supported single crowns or short-span fixed partial dentures. For each implant, the distance from implant shoulder to first crestal bone contact (DIB) was measured at the proximal surfaces with a digitizer/computer assembly. Statistically significant greater mean DIB were found at the 1-year (baseline) evaluation for: (1) maxillary sites overall (4.10 x 1.02 mm (SD)) compared with mandibular sites overall (3.61 +/- 1.03 mm); (2) maxillary anterior sites (4.08 +/- 0.97 mm) compared with mandibular posterior sites (3.60 +/- 1.05 mm); and (3) maxillary posterior sites (4.13 +/- 1.12 mm) compared with mandibular posterior sites. No statistically significant changes in DIB occurred in any of the jaw locations between the 1-year and 2-year evaluations.(ABSTRACT TRUNCATED AT 250 WORDS)