Marginal Bone Level Changes Research Articles

Influence of platform switching on periimplant bone loss: a systematic review and meta-analysis.

This meta-analysis aims to systematically review and draw a comparison between conventional implant designs and "platform-switched" implants in terms of crestal bone loss. Electronic (PubMed) and hand searches were conducted. Literature, clinical studies, and case reports pertaining to reduction of crestal bone loss and obtaining better esthetic outcome by platform switching were reviewed till October 2011. Controlled trials comparing marginal bone-level changes around platform-switched and platform-matched implants were selected. For the assessment of accuracy, meta-analysis was performed. The marginal bone loss around platform-switched implants was significantly lesser than platform-matched implants (mean difference [MD]: -0.34; 95% confidence interval [CI]: -0.37 to -0.30; P < 0.00001). According to this review and meta-analysis, platform switching seems to preserve periimplant bone and soft tissue levels. However, long-term clinical studies on the proper diameter of abutment without deformation and the effective degree of platform switching in terms of the bone resorption are still awaited.

The Effect of Flapless Surgery on Implant Survival and Marginal Bone Level: A Systematic Review and Meta‐Analysis

The clinical outcomes of implants placed using the flapless approach have not yet been systematically investigated. Hence, the present systematic review and meta-analysis aims to study the effect of the flapless technique on implant survival rates (SRs) and marginal bone levels (MBLs) compared with the conventional flap approach. An electronic search of five databases (from 1990 to March 2013), including PubMed, Ovid (MEDLINE), EMBASE, Web of Science, and Cochrane Central, and a hand search of peer-reviewed journals for relevant articles were performed. Human clinical trials with data on comparison of SR and changes in MBL between the flapless and conventional flap procedures, with at least five implants in each study group and a follow-up period of at least 6 months, were included. Twelve studies, including seven randomized controlled trials (RCTs), one cohort study, one pilot study, and three retrospective case-controlled trials (CCTs), were included. The SR of each study was recorded, weighted mean difference (WMD) and confidence interval (CI) were calculated, and meta-analyses were performed for changes in MBL. The average SR is 97.0% (range, 90% to 100%) for the flapless procedure and 98.6% (range, 91.67% to 100%) for the flap procedure. Meta-analysis for the comparison of SR among selected studies presented a similar outcome (risk ratio = 0.99, 95% CI = 0.97 to 1.01, P = 0.30) for both interventions. Mean differences of MBL were retrieved from five RCTs and two retrospective CCTs and subsequently pooled into meta-analyses; however, none of the comparisons showed statistical significance. For RCTs, the WMD was 0.07, with a 95% CI of -0.05 to 0.20 (P = 0.26). For retrospective CCTs, the WMD was 0.23, with a 95% CI of -0.58 to 1.05 (P = 0.58). For the combined analysis, the WMD was 0.03, with a 95% CI of -0.11 to 0.18 (P = 0.67). The comparison of SR presented a low to moderate heterogeneity, but MBL presented a considerable heterogeneity among studies. This systematic review revealed that the SRs and radiographic marginal bone loss of flapless intervention were comparable with the flap surgery approach.

Immediate function of partial fixed rehabilitation with axial and tilted implants having intrasinus insertion.

Implant-supported rehabilitation of the posterior maxilla could be challenging because hyperpneumatization of the maxillary sinus might reduce the bone height. In this study, the authors report preliminary results of a new treatment modality for the partial fixed rehabilitation of posterior maxilla with immediate function by using 1 anterior axial implant and 1 posterior tilted implant with intrasinus mesial insertion. From 2009 to 2011, 10 patients (6 women and 4 men) with missing upper premolars and molars were recruited and treated according to this protocol. Each patient received a partial fixed bridge supported by 1 axial anterior implant and 1 posterior implant placed with a 30-degree mesial inclination and intrasinus insertion. Autologous bone was positioned to fill the maxillary sinus cavity and to cover the exposed implant surface after elevation of the anterior sinus membrane. A prosthesis with immediate function was positioned within 3 hours, whereas a CAD/CAM final restoration was delivered 6 months later. Follow-ups at 6 and 12 months, and then annually, were scheduled. At each follow-up, plaque level and bleeding scores were assessed, and radiographic evaluation of marginal bone level change was performed at 1 year. The patients were followed up for a mean of 50 months (range, 42-57 mo). No implants were lost, and all prostheses were stable and functional, reporting 100% of implant and prosthetic success rates. After 1 year, bone loss had a mean (SD) of 1.0 (0.4) and 0.9 (0.5) mm for axial and tilted implants, respectively, with no statistically significant differences between them (P > 0.05). The preliminary results suggest that this approach could allow the rehabilitation of posterior maxilla with immediate function in case of reduced bone volume, representing an alternative technique to bone grafting, short implants, and zygomatic or pterygoid implants.

Five-year outcome of bone remodelling around implants in the maxillary sinus: assessment of differences between implants placed in autogenous inlay bone blocks and in ungrafted maxilla

The placement of implants in the posterior maxillary area is considered a reliable procedure, offering recognized rehabilitative advantages. The aim of this study was to evaluate the performance of dental implants placed in the sinus floor augmented with a block autograft by comparing the outcomes over 5 years with those of dental implants positioned in non-augmented bone. This retrospective cohort study included 16 patients who had undergone prosthetic rehabilitation supported by dental implants between 2000 and 2006. One implant per patient was included and assigned to one of two predictor groups: grafted versus ungrafted maxillary sinus. Changes in marginal bone level (MBL) and apical bone level (ABL) over time, at 1, 3, and 5 years, were the primary outcome variables. Appropriate pair-wise comparison tests were performed. No significant differences were seen with regard to ABLs and among times between the grafted group (nine implants) and the ungrafted group (seven implants). Significant marginal bone resorption was found over time, primarily at the buccal aspect, in both study groups. The bone surrounding the apex of dental implants appeared stable after sinus augmentation in the grafted area. The behaviour of the two groups with regard to loss of MBLs over time was very similar.

The effects of off-axial loading on periimplant marginal bone loss in a single implant

A discrepancy between crown width and implant width may contribute to potential bending overload. The purpose of this study was to evaluate the influence of the crown width-fixture width ratio on crestal bone loss around single dental implants placed in the first molar area. Seventy-six participants (37 men and 39 women; age range, 25-83 years; mean age [standard deviation], 56.3 ±10.6 years) were selected from individuals who were treated with single tooth implants between May 2004 and December 2009 at the Department of Periodontology, Gangnam Severance Dental Hospital. The marginal bone-level change and gingival parameters (modified plaque index and modified sulcus bleeding index) of the periimplant soft tissue were assessed 1 year after functional loading. The perpendicular distances from the vertical axis of each fixture to the most distal aspect of the crown and most mesial aspect of the crown were measured in the periapical radiographic view. No statistically significant relationship was found between crown width-fixture width ratio and the 1-year bone-level change (Pearson correlation, P=.06; Spearman rank test, P=.14). No statistically significant differences in marginal bone-level change were found between axial and nonaxial loading implants (2 independent samples t test; P=.19). The bone-level change for the surface adjacent and distant to the cantilever was not statistically significant (paired t test; P=.10). From this study, it may be concluded that off-axial loading that results from a high crown width-fixture width ratio does not increase the risk for periimplant marginal bone loss after 1-year functional loading.

Small‐diameter titanium Grade IV and titanium–zirconium implants in edentulous mandibles: three‐year results from a double‐blind, randomized controlled trial

The aim of this study was to compare crestal bone-level changes, soft tissue parameters and implant success and survival between small-diameter implants made of titanium/zirconium (TiZr) alloy or of Grade IV titanium (Ti) in edentulous mandibles restored with removable overdentures. This was a randomized, controlled, double-blind, split-mouth multicenter clinical trial. Patients with edentulous mandibles received two Straumann bone-level implants (diameter 3.3 mm), one of Ti Grade IV (control) and one of TiZr (test), in the interforaminal region. Implants were loaded after 6-8 weeks and removable Locator-retained overdentures were placed within 2 weeks of loading. Modified plaque and sulcus bleeding indices, radiographic bone level, and implant survival and success were evaluated up to 36 months. Of 91 treated patients, 75 completed the three-year follow-up. Three implants were lost (two control and one test implant). The survival rates were 98.7% and 97.3%, and the mean marginal bone level change was -0.78 ± 0.75 and -0.60 ± 0.71 mm for TiZr and Ti Grade IV implants. Most patients had a plaque score of 0 or 1 (54% for test and 51.7% for control), and a sulcus bleeding score of 0 (46.1% for test and 44.9% for control). No significant differences were found between the two implant types for bone-level change, soft tissue parameters, survival and success. After 36 months, similar outcomes were found between Ti Grade IV and TiZr implants. The results confirm that the results seen at 12 months continue over time.

A Prospective Noninterventional Study to Evaluate Survival and Success of Reduced Diameter Implants Made From Titanium-Zirconium Alloy

Narrow diameter implants may be at increased risk of overload due to occlusal forces; therefore, implants with higher fatigue strength may be beneficial. The aim of this observational study was to evaluate survival and success of narrow diameter (Ø 3.3 mm) TiZr alloy (Roxolid, Institut Straumann AG, Basel, Switzerland) implants for 2 years in daily dental practice. This was a prospective, non-interventional, multicenter study; no specific patient inclusion or exclusion criteria were applied. Each patient received at least one TiZr implant; the treatment plan, including implant loading and final restoration, was at the investigator's discretion. The primary outcome was implant survival and success after 1 year. Secondary outcomes included 2-year survival and success and marginal bone level change. A total of 603 implants were placed in 357 patients. Cumulative survival and success rates were 97.8% and 97.6%, respectively, after 1 year and 97.6% and 97.4%, respectively, after 2 years. Bone levels remained stable in the majority of patients, and soft tissue remained stable up to 2 years. Within the limitations of a non-interventional study design, TiZr implants showed excellent survival and success with minimal bone loss up to 2 years in daily dental practice. The results compare favorably with those of small-diameter implants in controlled clinical trials.

Annual failure rates and marginal bone‐level changes of immediate compared to conventional loading of dental implants. A systematic review of the literature and meta‐analysis

Immediate loading of dental implants appears to be a successful option. Questions still remain whether annual failure rates (AFRs) as well as annual marginal bone-level changes are comparable with conventionally loaded implants. Immediately loaded implants (≤24 h after implantation) do not show different annual survival rates or peri-implant bone-level changes as compared to conventionally loaded implants (≥3 months after implantation). An electronic search in the National Library of Medicine and in Cochrane Central Register of Controlled Trials was performed for articles published up to November 2013. Only publications in English were considered. Additionally, the bibliographies of the full-text papers were searched. Primary outcome variable was percentage AFR; secondary outcome variable was annual radiographic bone-level change. Electronic search yielded 154 full-text articles; ten randomized controlled clinical trials were eventually meta-analyzed. Annual failure rates were 2.3% and 3.4% for conventionally and immediately loaded implants, respectively. No difference in implant failure rates was found (RR: 0.82). Regarding marginal bone-level changes, the weighted mean difference (WMD) between immediate and conventional loading amounted to 0.02 mm at 1 year (P > 0.05), to 0.08 mm at 2 years (P > 0.05), -0.10 mm at 3 years (P > 0.05) and -0.3 mm at 5 years (P < 0.05). The total WMD for the combined follow-up was 0.01 mm (P > 0.05). No clinically relevant differences regarding annual failure rates or radiographic bone-level changes between conventionally and immediately loaded implants can be found for up to 5 years of follow-up.

Impact of platform switching on marginal peri‐implant bone‐level changes. A systematic review and meta‐analysis

ObjectiveTo address the focused question, is there an impact of platform switching (PS) on marginal bone level (MBL) changes around endosseous implants compared to implants with platform matching (PM) implant-abutment configurations?Material and methodsA systematic literature search was conducted using electronic databases PubMed, Web of Science, Journals@Ovid Full Text and Embase, manual search for human randomized clinical trials (RCTs) and prospective clinical controlled cohort studies (PCCS) reporting on MBL changes at implants with PS-, compared with PM-implant-abutment connections, published between 2005 and June 2013.ResultsTwenty-two publications were eligible for the systematic review. The qualitative analysis of 15 RCTs and seven PCCS revealed more studies (13 RCTs and three PCCS) showing a significantly less mean marginal bone loss around implants with PS- compared to PM-implant-abutment connections, indicating a clear tendency favoring the PS technique. A meta-analysis including 13 RCTs revealed a significantly less mean MBL change (0.49 mm [CI95% 0.38; 0.60]) at PS implants, compared with PM implants (1.01 mm [CI95% 0.62; 1.40] (P < 0.0001).ConclusionsThe meta-analysis revealed a significantly less mean MBL change at implants with a PS compared to PM-implant-abutment configuration. Studies included herein showed an unclear as well as high risk of bias mostly, and relatively short follow-up periods. The qualitative analysis revealed a tendency favoring the PS technique to prevent or minimize peri-implant marginal bone loss compared with PM technique. Due to heterogeneity of the included studies, their results require cautious interpretation.

Marginal bone response of implants with platform switching and non‐platform switching abutments in posterior healed sites: a 1‐year prospective study

ObjectivesThis 1-year prospective study evaluated the implant success rate and marginal bone response of non-submerged implants with platform and non-platform switching abutments in posterior healed sites.Material and methodsNineteen patients (9 male, 10 female) with posterior partially edentulous spaces, between the ages of 23 and 76 (mean = 55.4 years), were included in this study. A total of 30 implants (15 implants restored with platform switching [PS] abutments [control] and 15 implants restored with non-platform switching [NPS] abutments [test]) were assigned between two groups using a randomization procedure. The definitive abutments with conical connections were placed at the time of surgery, and the definitive restorations were placed at 3 months. All patients were evaluated clinically and radiographically using standardized radiographs at time of implant placement (0), 3, 6 and 12 months after implant placement. Data were analyzed using Friedman test with post hoc pairwise comparisons, Mann–Whitney U-test, and Pearson's chi-square test at the significance level of α = 0.05.ResultsAt 12 months, all 30 implants remained osseointegrated corresponding to a 100% success rate. The overall mean marginal bone level change at 12 months was −0.04 ± 0.08 mm for PS group and −0.19 ± 0.16 mm for NPS group. Statistically significant difference in the marginal bone level change was observed between groups at 0 to 12 months and 3 to 12 months (P < 0.05).ConclusionsThis 1-year randomized control study suggests that when a conical implant–abutment connection is present, similar peri-implant tissue responses can be achieved with platform switching and non-platform switching abutments.

A radiological evaluation of marginal bone around dental implants: An in-vivo study.

Context:This article presents an original research conducted at Government Dental College, PGIDS, Rohtak.Aims:(1) To evaluate the marginal bone level changes around dental implants based on the radiological examination. (2) To evaluate the relationship of various parameters, i.e., gender, implant length, implant diameter and location of implants on the amount of bone loss around dental implants.Materials and Methods:An in-vivo study was undertaken to evaluate the crestal bone loss on mesial and distal aspect of implants, using standardized intra-oral periapical at the end of 6 months after placing the implants, but before prosthetically loading it.Statistical Analysis Used:Student's unpaired t-test.Results:Bone loss was measured and values were recorded immediately after implant placement and after 6 months.Conclusions:(1) Bone loss on mesial and distal aspects of implants was found to be same after period of 6 months. (2) Bone loss was found to be same in both 13 mm and 10 mm implants on mesial aspect, whereas on distal aspect, it was more in 10 mm implants. (3) Bone loss was found to be same in both 3.5 mm and 4.3 mm diameter implants on both mesial and distal aspects of implants. (4) Bone loss was found to be same in both maxilla and mandible on both mesial and distal aspects of implants. (5) Bone loss was found to be more in females on both mesial as well as distal aspects of implants.

Radiological evaluation of the cresco system in combination with osseospeed implants: a preliminary 3-year report

In this preliminary study, the 3-year radiological outcomes of Osseospeed implant-supported fixed complete or partial prostheses made with two different laboratory protocols were compared. A convenience sample of 34 patients, who were either partially or completely edentulous in either jaw, were randomly assigned to two groups, of 17 patients each, using either a traditional laboratory protocol (control group) or the Cresco one (test group). The study's objective was an assessment of marginal bone loss around implants, measured on intraoral radiographs at 3-year follow-up. None of the implants inserted was lost during the study and radiological measurements of marginal bone level changes revealed that the mean marginal bone loss was respectively 0,73±0,33mm for test group and 0,88±1,13mm for control group. The differences between test and control groups were not statistically significant. This preliminary study did not demonstrate statistically significant differences in marginal bone loss around implant-prostheses prepared with the two different laboratory protocols, over the 3-year observational period.

Three-year follow-up of immediately loaded implants in the edentulous atrophic maxilla: a study in patients with poor bone quantity and quality.

Immediate loading of implants in the edentulous maxilla has previously been successfully performed and reported. Severe resorption of the maxillary alveolar crest presents a more demanding situation for the restorative team. Thus, it would be valuable to assess outcomes for this immediate loading treatment protocol in subjects with marked maxillary alveolar crest atrophy. This study evaluated the 3-year results of dental implants that were immediately restored with provisional fixed prostheses in atrophic maxillae without previous augmentation. Two centers enrolled subjects with resorbed edentulous maxillae (Lekholm and Zarb quality 3 or 4 and quantity C, D, or E). Six implants were placed in each subject and restored with screw-retained fixed provisionals within 24 hours. Impressions were taken for definitive restorations, which were placed 20 to 24 weeks later. Radiographs were used to analyze marginal bone level changes throughout the study. Fifty-one patients received 306 implants. Forty-five patients remained in the study at the 3-year follow-up visit and successfully used their definitive prostheses. Sixty-two percent of the implants were placed in bone quantity C and quality 3 or 4, and 38% were placed in quantity D and quality 3 or 4 bone. Thirteen implants in six subjects were lost, resulting in a cumulative survival rate of 96% after 3 years. The mean marginal bone loss during the first year was -0.4 ± 0.8 mm (255 implants); at 3 years it was -0.6 ± 1.1 mm (253 implants). Data from the first 3 years of this study revealed good clinical outcomes. Careful selection of patients and planning by the restorative team can enable successful treatment outcomes for patients presenting with marked resorption of the edentulous maxilla.

Different loading times for dental implants – no clinically important differences?

The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, and Embase databases were searched. Reference lists of identified articles were also scanned for relevant papers. There were no restrictions on language or date of publication. Randomised controlled trials (RCTs) of parallel group design and of split-mouth design including root-form osseointegrated dental implants having a follow-up of four months to one year after loading were included. Data were independently extracted, in duplicate, by at least two review authors. The outcome measures were prosthesis and implant failures and radiographic marginal bone level changes. Risk of bias was assessed for each trial by at least two review authors. Results were combined using fixed-effect models with mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI). Twenty-six trials involving a total of 1217 participants and 2120 implants were included. The risk of bias was low in three trials, high in 12 and unclear for the remaining eleven. In nine studies there were no prosthetic failures within the first year, with no implant failures in seven studies and the mean rate of implant failure in all 26 trials was a low 2.5%. From 15 RCTs comparing immediate with conventional loading there was no evidence of a difference in either prosthesis failure (RR 1.87; 95% CI 0.70 to 5.01; 8 trials) or implant failure (RR 1.65; 95% CI 0.68 to 3.98; 10 trials) in the first year. However, there is some evidence of a small reduction in bone loss favouring immediate loading (MD -0.10 mm; 95% CI -0.20 to -0.01; P = 0.03; 9 trials), but this very small difference may not be clinically important. From three RCTs which compared early loading with conventional loading, there is insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. Six RCTs compared immediate and early loading and found insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. From the two trials that compared occlusal loading with non-occlusal loading there is insufficient evidence to determine whether there is a clinically important difference in the outcomes of prosthesis failure, implant failure or bone loss. No trials were identified which evaluated progressive loading of implants. Overall there was no convincing evidence of a clinically important difference in prosthesis failure, implant failure or bone loss associated with different loading times of implants. More well-designed RCTs are needed and should be reported according to the CONSORT guidelines.

Effect of Crown to Implant Ratio and Anatomical Crown Length on Clinical Conditions in a Single Implant: A Retrospective Cohort Study

The aim of this retrospective cohort study was to evaluate the long-term influence of the crown-to-implant (C/I) ratio and anatomical crown length on clinical conditions around Astra single dental implants placed in the premolar and molar regions. Seventy-six subjects were selected from patients who had been treated with single Astra implants for replacement of missing premolars and molars. The peri-implant marginal bone level change was assessed 1 year after functional loading and 6 years after functional loading. To predict the peri-implant marginal bone level change using clinical and radiographic data, a multiple linear regression model was applied. The Wilcoxon rank sum test was used to analyze difference median in technical complications. The C/I ratio and anatomical crown length were not associated with peri-implant marginal bone loss or changes in the bone level at 6 years (p = .48, p = .31). However, the modified plaque index, modified sulcus bleeding index, and smoking status influenced the peri-implant marginal bone loss (p < .05, r(2) = 0.54). In addition, the patient with technical complication group did show significantly increased anatomical crown length (p < .05) CONCLUSIONS: The higher C/I ratio and anatomical crown length did not increase the risk of peri-implant marginal bone loss during 6 years of functional loading. In addition, higher anatomical crown lengths are associated with higher technical complications.

Impact of plasma of argon cleaning treatment on implant abutments in patients with a history of periodontal disease and thin biotype: radiographic results at 24‐month follow‐up of a RCT

A lack of evidence is present in literature regarding the clinical relevance of micropollution and bacterial contamination present on customized titanium abutments following laboratory stages and steaming cleaning procedures. To preserve abutments from such pollutants, plasma of argon cleaning of customized abutments was advocated. The aim of this prospective, randomized, match-paired, triple-blinded, controlled, clinical trial is to longitudinally assess radiographical marginal bone-level changes around implants restored according to the platform switching and "one-abutment-one-time" concepts, using commercially available abutments, with and without plasma of argon cleaning treatment after customization. Thirty patients with thin gingival biotype, a history of periodontal disease, and in general good health received one implant in the anterior maxilla or premolar region. Patients were randomly assigned to control (abutment subjected only to usually adopted cleaning protocol by steam) and test group (abutment subjected to plasma of argon treatment). Periapical standardized digital radiographs were taken at the time of crown connection (T0), 6 (T1) and 24 months after the final restoration (T2). Average mesial-distal bone-level changes mean values with standard deviations (SD) were calculated. The Mann-Whitney U-test was selected to identify differences in bone-level changes between test and control groups. An average interproximal bone loss of 0.16 mm (SD: 0.17) and 0.07 mm (SD: 0.34) was revealed in the control and test group at 6 months (T1), respectively, while after 24 months, groups showed a mean bone-level changes of 0.38 mm (SD: 0.44) and 0.11 mm (SD: 0.14), respectively. Statistically significant differences among control and test groups were found at both time points. Intergroup comparison relived absence of statistically significant difference. Plasma-cleaning treatment of implant titanium abutments, together with platform switching and one-abutment-one-time concepts, could be favorable in terms of hard-tissue-level changes, also in critical conditions such as in patients with a history of periodontal disease, presenting thin gingival biotype.

Changes of Marginal Bone Level in Patients with “Progressive Bone Loss” at Brånemark System® Implants: A Radiographic Follow‐Up Study over an Average of 9 Years

Patients have in many studies been identified with progressive bone loss and peri-implantitis problems, but few studies are available where these groups of patients have been followed up. The purpose of this paper is to study further progression of bone loss in a cohort of 182 patients that have been reported to suffer from "progressive" bone loss and peri-implantitis. Altogether, 182 patients that have earlier been identified to suffer from "progressive" bone loss formed the present study group. Data from patients' files have been retrieved, and intraoral radiographs have been analyzed for further bone level changes. Bone loss has been measured from time of inclusion into the present group to last available radiographs. Within each patient, one or several implants were diagnosed to suffer from "progressive" bone loss (affected), whereas others are not (unaffected). Altogether, 145 patients (80%) were radiographically followed up on an average of 9.1 years (SD 3.77) after inclusion. Twenty-four implants (3.1%) were lost in 16 patients (11%). Marginal bone loss was on an average 0.3 mm (SD 0.75) at stable implants with only small differences between "affected" and "unaffected" implants. In total, 67 implants (8.6%) presented an annual bone loss of >0.2 mm. Oral hygienist treatment and/or peri-implantitis surgery did not neither reduce implant failure rate nor marginal bone loss in 88 treated patients as compared with untreated patients. Less than one-third of the patients identified with "progressive bone loss" showed one or more implants as failures or with high annual bone loss (>0.2 mm) during follow-up (11.6% of implants). Treated patients (oral hygienist and/or surgery) did not perform better than untreated patients with regard to bone loss or implant failure.

Clinical and radiographic evaluation of early loaded narrow-diameter implants: 3years follow-up.

To evaluate the clinical reliability of narrow implants placed in a one-stage procedure and early loaded in the upper and lower incisor region. This is a prospective, single-arm, multicenter study in which patients with missing natural dentition in upper lateral and lower incisor positions were enrolled. Eligible implants (OsseoSpeed™ TX 3.0S, DENTSPLY Implants) were of three different lengths and of 3.0 mm in diameter. One-stage surgery was performed and healing abutment connection took place. Placement of the permanent single crown took place after a 6-10 weeks healing period. Clinical and radiographic checks were performed at implant placement, loading, and at the 6, 12, 24, and 36 months follow-up visits. A total of 69 subjects with 97 implants have been included in this study. From surgery to 36 months follow-up, 5.6% of the implants showed bone loss of more than 1 mm, while no bone loss at all were observed for 57.3% of the implants. The mean marginal bone level change from surgery to the 6, 12, and 36 months follow-up visits was -0.27, -0.11, and -0.09 mm, respectively. The total survival rate after 3 years is 95.5%. The data presented show stable marginal bone levels as well as healthy soft tissue around OsseoSpeed™ TX 3.0S implants, after 3 years of function. An interesting finding from this investigation was that a longer healing period before crown placement and loading contributed to statistically significant less marginal bone loss between loading and the 1-year follow-up visit (Galindo-Moreno et al. 2012). This finding, associated with a stable probing pocket depth and a stable crown-gingiva distance, using a one-stage surgical procedure helps to maintain the integrity of the peri-implant soft tissues. Narrow implants can be considered as a valid solution in the treatment of the localized narrow bony defects in the anterior area with reduced spaces between the natural teeth.

임플란트 식립 후 초기 안정성의 변화

골치유 기간 중 임플란트-골 계면에서 일정 수준 이상의 미세동요가 발생하게 되면 임플란트의 골유착이 방해받게 되므로 임플란트 식립 후 초기 골반응에 관해 임플란트 안정성은 하나의 지표가 된다. 본 연구의 목적은 임플란트 식립 후 전향적인 연구를 통해 초기 임플란트 안정성 변화를 추적하여 골치유 양상을 추론하고자 하였다. 총 26명의 환자에게 식립된 30개의 임플란트를 대상으로 하악골에 1회법으로 식립 직후 1주 간격으로 12주간 공진주파수분석을 시행하여 초기 안정성의 변화를 구하였으며 식립 직후와 1개월 간격으로 변연골 흡수 정도를 방사선학적 방법으로 측정하였다. 식립 직후와 각 치유기간 동안의 ISQ값 비교에서 식립 4주에서 6주사이에 골질에 따른 차이를 보였으나(P<0.05), 6주 이후에는 골질군 간에는 임플란트 안정성 변화에 차이가 없었다(P>0.05). 방사선학적 검사에서는 변연골의 차이가 관찰기간내에 유의하게 변화하지 않았다(P>0.05). 임플란트 식립 후 초기 골치유과정은 골흡수과정에 연속적인 과정으로 4주 이후 바람직한 골치유과정이 진행됨을 공진주파수분석으로 관찰할 수 있었다. The concept of implant stability was basically originated from the relative condition of bone-implant interface and has some meanings for evaluation of that interface. In addtion, it has been used for the investigation of initial bone healing process after fixture installation because a degree of micromotion around interface can affect unfavorable clinical results. The purpose of this study is to investigate the mode of initial bone healing from fixture installation through prospective trial. Thirty fixtures were consecutively installed in mandibles of 26 patients with single tooth loss area and then healing abutment were secured for one-stage surgery meothod. Resonance frequency analysis was performed with one week interval during 12 weeks and periapical radiographs were taken at each month. Although marginal bone level change was not shown through observation period (P>0.05), statistical difference of implant stability was shown through 4 and 6 week (P<0.05) and was not shown after 6 week (P>0.05) according to the bone quality. Initial bone healing process is a successive process of bone resorption and favorable bone healing result might be postulated at 4 week interval after installation through RFA.

Single-Tooth Replacement in the Anterior Maxilla by Means of Immediate Implantation and Early Loading: Clinical and Aesthetic Results at 5 Years

The hypothesis of the present study was that the early loading of single implants-supported restorations, replacing single extracting teeth in the anterior region of the maxilla in case of fresh extraction sockets with residual hard and soft tissue preservation, could be a successful procedure. Twenty-one implants were placed into maxillary anterior fresh extraction sockets using a flapless technique. Temporary restorations, which were fabricated from the impression taken immediately after implant placement, were connected within 2 weeks. These temporary restorations were adjusted in order to avoid any direct occlusive contacts. Six months after implantation, the implants were restored with single-teeth all-ceramic prostheses. Patients were followed for 5 years. Radiographic and clinical examinations were made at baseline, at time of definitive crowns delivery, and each subsequent year. Survival rate, cortical bone responses, and peri-implant mucosal responses were evaluated. One implant was lost at 6 months. Clinical osseointegration of 20 implants was achieved (95.2% implant survival rate after 5 years) with minimal gingival recession and papillae preservation. The mean change in marginal cortical bone level was 0.40 mm at 6 months and 0.83 mm at 5 years. Within the limit of the present study, the data indicate that, under a strictly controlled oral hygienic regimen, single-tooth implants, with immediate placement and early loading protocol, may be used in anterior maxillary fresh extraction sockets with residual hard and soft tissues preservation, if patients are selected carefully and if high primary stability is strictly followed.