Retrospective radiographic observational study of 1692 Straumann tissue-level dental implants over 10 years. II. Marginal bone stability

Progressive bone loss and bleeding on probing: A cohort study

AIM

To investigate whether a progressive marginal bone loss (PMBL) occurring beyond the initial bone remodeling (IBR) is linked with bleeding on probing.

MATERIALS AND METHODS

A total of 70 partially edentulous patients exhibiting 112 two-piece bone-level implants were included in this retrospective study. Panoramic radiographs were obtained after implant insertion (T0), after delivery of a final prosthetic restoration (T1) and subsequently during the 1-(T2), 5-(T3), 10-(T4), and 15-years (T5) follow-up visits. At each time point, radiographic marginal bone levels were assessed from the implant shoulder to the first bone-to-implant contact at mesial and distal aspects. The IBR was defined as a bone loss occurring up to prosthesis delivery, that is, from T0 to T1. The PMBL was defined as bone loss occurring after T1. At T2, T3, T4, and T5, the presence or absence of bleeding on probing (BOP) was recorded at four sites. A median regression with mixed models was performed to assess the difference of PMBL in PMBL + BOP+ and PBML + BOP- groups.

RESULTS

Over the mean implant functioning time of 4.44 ± 4.91 years, 38 (34%) implants showed no PBML, whereas 74 (66%) implants featured PMBL. Of these, 35 (47%) and 39 (53%) implants were assigned to the PMBL + BOP- and PMBL + BOP+ groups, respectively. The mean PMBL after 1, 5, 10, and 15 years were comparable between implants featuring PMBL with or without BOP. At 1 year, BOP intensity significantly correlated PMBL, with each increase in one BOP-positive site being associated with increase in PMBL by 0.55 mm (p = 0.038), whereas this association was not found at 5, 10, and 15 years. The IBR values in the no PBML, PMBL + BOP+, and PBML + BOP- groups were -0.24 ± 0.31, -0.41 ± 0.59, and -0.24 ± 0.33 mm, respectively, with no significant differences found among the groups.

CONCLUSION

Progressive bone loss at implant sites is not always linked with bleeding on probing.

Radiographic marginal bone level evaluation around two different tissue-level implant systems: a one-year prospective study

BACKGROUND

Marginal bone loss, is a frequently reported variable in the evaluation of dental implants. The primary objective of this study was to evaluate radiographic marginal bone level changes around the two different tissue-level implant systems placed adjacently in the posterior maxilla or mandible. The influence of implant macro-geometry and vertical soft tissue thickness on marginal bone loss were also evaluated.

METHODS

Seven patients were included in the study and a total of 18 implants were analyzed. Each patient received two different implants placed adjacently in the maxilla or the mandible. The implants used in our study were either Straumann® SP cylindrical implants or JD Octa® tapered implants. During the surgery, vertical soft-tissue thickness was measured with a periodontal probe placed on the top of the bony crest and in the center of the future implant site. Healing abutments were then seated. Three months following implant placement, impressions were taken, and screw-retained metal ceramic prostheses were delivered. Standardized intraoral radiographs were taken immediately after implant placement and one year following implant loading in order to assess marginal bone level changes.

RESULTS

Results showed a mean marginal bone loss of 0.55±0.5 mm for Straumann® SP implants and 0.39±0.49 mm for JD Octa® implants after one year of loading and the difference was not statistically significant between the two systems. A statistically significant correlation was found between soft tissue thickness and marginal bone loss; in sites with thin mucosal tissues (≤2 mm), there was significantly greater bone loss compared to sites with thick, soft tissues (> 2 mm) in both implants.

CONCLUSIONS

Radiographic marginal bone loss was not statistically different between the two implant systems at the one-year examination period. Moreover, vertical soft tissue thickness influenced marginal bone loss regardless of the implant system used.

Marginal bone loss of tissue- or bone-level implants after simultaneous guided bone regeneration in the posterior mandibular region: A retrospective cohort study

PURPOSE

To analyze the marginal bone loss (ΔMBL) of tissue- or bone-level implants after placed with simultaneous guided bone regeneration (GBR).

MATERIALS AND METHODS

A total of 151 patients who received 104 tissue-level or 128 bone-level implants placement with simultaneous GBR in the mandibular posterior region between January 2011 and December 2016 were included in this study. The marginal bone level (MBL) was recorded using the radiographic data obtained at implant placement, second-stage surgery, and the follow-up visit. Generalized estimating equation (GEE) was used to compare the ΔMBL of tissue- and bone-level implants, and the influencing factors of ΔMBL were further analyzed.

RESULTS

At the last follow-up visit, the MBL of tissue-level implants was 0.73 ± 0.86 mm, above the rough-smooth interface, while that of bone-level implants was 0.82 ± 1.05 mm, above the implant platform. The ΔMBL of tissue-level implants was 1.03 mm, which was slightly higher than 0.81 mm of bone-level implants, but there was no significant difference (p > 0.05). No contributing factor associated with ΔMBL was identified by multivariate regression analysis in this study.

CONCLUSION

Within the limits of this retrospective analysis, the ΔMBL of tissue-level implants is similar to that of bone-level implants after placed with simultaneous GBR, and both types of implants can achieve desirable marginal bone stability.

Influence of Periodontitis, Implant, and Prosthesis Characteristics on the Peri-Implant Status: A Cross-Sectional Study

Background

The association between peri-implant diseases and the periodontal, implant, and prosthesis characteristics has been characterized in various ways.

Purpose

The aim of this study was to evaluate the link between the peri-implant and periodontal status and the influence of implant and prosthesis parameters during implant follow-up.

Materials and Methods

One hundred and seven patients with a total of 310 implants that had at least one year of function who were attending periodontal and implant maintenance at a university clinic setting were included in this cross-sectional study. The demographic, periodontal, peri-implant tissue, implant, and prosthesis parameters were recorded. A pocket depth > 4 mm with bleeding on probing defined periodontal/peri-implant soft tissue diseased sites. Analyses were performed at the patient and implant levels using univariable and multivariable mixed regression analysis.

Results

The mean implant follow-up was 7.22 years. At the patient level, the bleeding on probing and pocket depth measurements were more pronounced around the implant than around the teeth. The opposite was observed for plaque and the clinical attachment levels. At the implant level, multivariable analysis showed that the periodontal and corresponding peri-implant tissue parameters, such as diseased sites, were closely related. The implant location, bone level, and number were selectively associated with the implant bone level, while cemented retention and emergence restoration profile influenced the implant pocket depth.

Conclusions

The present study suggested that clinical peri-implant and periodontal soft tissue statuses were different, which could be a consequence of the initial implant and prosthesis healing process. However, during implant follow-up, the peri-implant parameters were predominantly associated with their corresponding periodontal parameters regardless of an association with the implant and prosthesis characteristics. This trial is registered with ClinicalTrials.gov ID: NCT03841656.

Bone loss-related factors in tissue and bone level dental implants: a systematic review of clinical trials

Dental implants are popular for dental rehabilitation after tooth loss. The goal of this systematic review was to assess bone changes around bone-level and tissue-level implants and the possible causes. Electronic searches of PubMed, Google Scholar, Scopus, and Web of Science, and a hand search limited to English language clinical trials were performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines up to September 2020. Studies that stated the type of implants used, and that reported bone-level changes after insertion met the inclusion criteria. The risk of bias was also evaluated. A total of 38 studies were included. Eighteen studies only used bone-level implants, 10 utilized tissue-level designs and 10 observed bone-level changes in both types of implants. Based on bias assessments, evaluating the risk of bias was not applicable in most studies. There are vast differences in methodologies, follow-ups, and multifactorial characteristics of bone loss around implants, which makes direct comparison impossible. Therefore, further well-structured studies are needed.

Early peri-implant bone loss as a predictor for peri-implantitis: A 10-year prospective cohort study

PURPOSE

To evaluate the effect of early bone loss (EBL), on long-term bone stability and future peri-implantitis development.

MATERIALS AND METHODS

Patients referred for implant placement between 2005 and 2009 were consecutively treated and followed for 10 years. After 10 years, patients were invited for a scientific diagnostic visit to evaluate implant survival and bone loss. Bone level changes were compared with baseline. Non-parametric testing was performed in cross-tabs (Pearson Chi-square and Fishers's exact test). Kaplan-Meier-estimated survival curves were plotted for different thresholds for EBL at different timepoints. Generalized linear mixed models with binomial distribution and logit link for peri-implantitis were fitted. An adjusted logistic mixed model was made to evaluate peri-implantitis, in relation with smoking status, history of periodontitis, and EBL > 0.5 mm.

RESULTS

Four hundred and seven patients (mean age of 64.86 years [range 28-92, SD 10.11]), with 1482 implants, responded to the 10-year recall invitation. After an average follow-up time of 10.66 years (range 10-14, SD 0.87), implant survival was 94.74%. Mean crestal bone loss after 10 years was 0.81 mm (SD 1.58, range 0.00-17.00). One hundred and seventy five implants in 76 patients had peri-implantitis (11.8% on implant level, 18.7% on patient level). EBL of 0.5, 1, and 2 mm were significant predictors for peri-implantitis and implant loss after 10 years. Implants with EBL ≥0.5 mm during the first year of function showed a 5.43 times higher odds for future peri-implantitis development. Probability in developing peri-implantitis was 52.06% when smoking, Periodontal history and EBL of >0.5 mm was combined.

CONCLUSION

The present study suggests that EBL is a predictor for long-term peri-implant pathology, with a significant higher risk for peri-implantitis when early bone loss exceeds the thresholds of 0.5 and 1 mm, especially when additional risk factors such as smoking or susceptibility for periodontal disease prior to implant treatment are present. Clinical trial registration number B670201524796.

Clinical and radiographic variables related to implants with simultaneous grafts among type 2 diabetic patients treated with different hypoglycemic medications: a retrospective study

Background

The influence of different hypoglycemic agents on peri-implant variables among type 2 diabetes mellitus patients is still unclear. Therefore, the aim of this study was to assess the radiographic marginal bone loss and clinical parameters around implants in patients using different hypoglycemic agents.

Methods

In this retrospective cohort study, the dental implant records of type 2 diabetes mellitus patients who met the inclusion criteria were collected. The patients using only single medication as follows: insulin, metformin, or glucagon-like peptide-1 (GLP-1) drugs, were grouped according to their medication. These patients received implant placement with the same initial status, and all the prosthesis restorations were cement-retained ceramic crowns. The peri-implant marginal bone levels were evaluated by periapical radiographs immediately after implant placement and at 1 and 2-year follow-up visits. The baseline characteristics were compared among groups. The peri-implant radiographic marginal bone loss and clinical parameters were preliminarily compared using the Kruskal–Wallis test, and then the covariates were controlled by covariance analysis. Bonferroni post hoc adjustment test was performed for the multiple comparisons.

Results

After a review of more than 7000 medical records, a total of 150 patients with 308 implants at 1-year follow-up were assessed. The peri-implant marginal bone loss in the GLP-1 drug group was significantly smaller than the insulin group and metformin group (P < 0.01). The radiographic bone loss in the metformin group was higher than the insulin group (P < 0.05). Some of these included patients were lost to follow-up. Only 74 patients with 129 implants completed the 2-year follow-up. The radiographic bone loss in the metformin group was still higher than the insulin group (P < 0.05) and GLP-1 group (P < 0.01). There was no significant difference in the BOP (+) and the mean PD among groups (P > 0.05).

Conclusions

The radiographic variables were not exactly the same among the patients with different hypoglycemic agents at both the 1 and 2-year follow-ups. After ensuring consistency in baseline characteristics, the positive effect of GLP-1 drugs on peri-implant bone remodeling may be no less than insulin or metformin. More studies are needed to verify the direct effect of these drugs on peri-implant bone.

Clinical trial registration number ChiCTR2000034211 (retrospectively registered).

Association between periodontitis treatment outcomes and peri-implantitis: A long-term retrospective cohort study

OBJECTIVES

Retrospectively evaluate the association of periodontal treatment outcomes and the prevalence of peri-implant diseases around tissue-level implants.

MATERIALS AND METHODS

Eighty-six patients with 260 tissue-level implants attending supporting periodontal and implant therapy for more than 3 years were evaluated. Clinical and radiographic periodontal and implant data were recorded at initial examination (T0), before implant placement (T1) and at final re-examination (T2). Two definitions of peri-implantitis severity, PIBE and PIKA, were used corresponding to the presence of periodontal pocket ≥5 mm or ≥6 mm with bleeding on probing or suppuration and radiographic signs of a bone level ≥2 mm, or ≥3 mm during implant follow-up, respectively. Analyses were performed at patient level.

RESULTS

The mean implant follow-up per patient was 9.4 years and 38.0% of patients had implant for at least 10 years. Two implants were lost due to peri-implantitis. The prevalence of patients with PIKA and PIBE was 15.1% and 12.8%, respectively. Residual periodontal pockets, clinical attachment loss and bone loss/age at T2 were more pronounced in patients with PIKA and PIBE. Cox regression analysis adjusted with the number of implants per patient showed that residual pockets at T1 were independently associated with PIKA and PIBE. Initial diagnosis of severe periodontitis was associated with PIBE incidence.

CONCLUSIONS

The present study showed that periodontal conditions before implant placement are a risk indicator for peri-implantitis incidence. During implant follow-up, the severity of periodontal status appeared to be a reliable indicator of patient susceptibility to peri-implantitis.

Clinical feasibility and benefits of a tapered, sand-blasted, and acid-etched surfaced tissue-level dental implant

BACKGROUND

It has been 50 years since Brånemark first introduced the concept of osseointegration. Since then, numerous ongoing research, developments, and optimization of implant properties have been conducted. Despite the high survival and success rates of dental implants, failures still occur in a small number of patients that are being rehabilitated by implants. The purpose of this study was to evaluate the survival and success rate of the Stella® implants that incorporate sand-blasted and acid-etched (S&E) surface treatment and tapered body design to confirm their clinical feasibility and benefits after placement.

METHODS

We reviewed 61 partially and fully edentulous patients who underwent a tapered, S&E surfaced tissue-level implant placement between May 2013 and February 2016 in the Department of Oral and Maxillofacial Surgery in the Seoul National University Dental Hospital. Patient characteristics and treatment results were collected, and records of dental implants were analyzed clinically and radiologically.

RESULTS

A total of 105 implant fixtures were placed in these patients. The mean age at the time of the surgery was 63.7 years with a range of 31 to 88 years. In total, 4.0-mm and 4.5-mm diameter implants were the most frequently used dental implants (40%, 49%) in this study. Implants 8.5 mm in length were predominantly used (60%). Seventy dental implants were placed in the mandible (70%), and only one dental implant was placed in the maxillary anterior region. At the end of the 5-year observation period, the success rate of the Stella® implants was 98.1%. Among the 105 implants placed, 2 were considered to be failures. Summarizing the clinical and radiographic results, the remaining 103 implants were considered successfully integrated.

CONCLUSION

The overall success rate was 98.1%. The tapered, S&E surfaced tissue-level implant system exhibited great performance in a variety of clinical situations including failed implant sites that enabled predictable and successful treatment outcomes. The effectives of a tapered design of tissue level, not a parallel design, are shown in this clinical report.