One‐piece zirconia oral implants for single‐tooth replacement: Three‐year results from a long‐term prospective cohort study

Aim

This 3‐year report of a prospective long‐term cohort investigation aimed to evaluate the clinical and radiographic outcomes of a one‐piece zirconia oral implant for single‐tooth replacement.

Materials and Methods

Sixty‐five patients received a 1‐stage implant surgery with immediate temporization. Standardized radiographs were taken at implant insertion, after 1 year, and after 3 years to monitor peri‐implant bone levels. A univariate analysis of the association of different baseline parameters on marginal bone loss from implant insertion to 36 months was performed. Soft‐tissue parameters were evaluated at prosthesis insertion, after 6 months, after 1 year, and at the 3‐year follow‐up.

Results

After 3 years, six posterior site implants were lost, giving a cumulative survival rate of 90.8%. The mean marginal bone loss was 1.45 mm; 35% of the implants lost at least 2 mm bone, and 22% more than 3 mm. The univariate analysis did not identify any parameter associated with marginal bone loss. Probing depth, clinical attachment level, and bleeding index increased over 3 years, and plaque index decreased.

Conclusions

The low survival rate of the presented ceramic implant and especially the high frequency of advanced bone loss are noticeable but remain unexplained.     

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

Objectives: 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. Material and methods: 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. Results: 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. Conclusions: 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. To cite this article:
Chang M, Wennström JL. Peri‐implant soft tissue and bone crest alterations at fixed dental prostheses: a 3‐year prospective study.
Clin. Oral Impl. Res. 21, 2010; 527–534.
doi: 10.1111/j.1600‐0501.2009.01874.x     

Efficacy of 0.12% Chlorhexidine Gluconate for Non‐Surgical Treatment of Peri‐Implant Mucositis

Background: Because peri‐implant mucositis may progress to peri‐implantitis, effective treatment resulting in resolution of inflammation could prevent peri‐implantitis. Current treatment protocols for this condition are still unpredictable. The purpose of this study is to analyze efficacy of non‐surgical treatment for patients with peri‐implant mucositis during a 6‐month follow‐up period. Methods: This controlled, randomized, double‐masked clinical trial included 37 patients diagnosed with peri‐implant mucositis, randomly assigned into test group (basic periodontal therapy + 0.12% chlorhexidine) with 61 implants; and control group (basic periodontal therapy + placebo) with 58 implants. Therapy consisted of adaptation of the full‐mouth scaling and root planing protocol. Clinical parameters of visible plaque index (VPI), gingival bleeding index (GBI), probing depth (PD), and bleeding on probing (BOP) were measured in implants and were evaluated at baseline and at 1, 3, and 6 months post‐therapy. Data were analyzed using the split‐plot analysis of variance and χ² tests with a significance level of 5%. Results: Intragroup analysis showed that VPI, GBI, PD, and BOP presented statistically significant improvements compared with baseline. No statistically significant differences were found between the test and control groups at any time. Conclusions: Both isolated mechanical therapy and its association with 0.12% chlorhexidine mouthwash reduced peri‐implant mucositis. Therefore, 0.12% of chlorhexidine was not more effective than placebo.     

Bone‐to‐Implant Contact Around Immediately Loaded Direct Laser Metal‐Forming Transitional Implants in Human Posterior Maxilla

Objective: Direct laser metal forming (DLMF) is a procedure in which a high‐power laser beam is directed onto a metal powder bed and programmed to fuse particles according to a computer‐aided design file, generating a thin metal layer. This histologic study evaluated the bone‐to‐implant contact (BIC%) around immediately loaded DLMF transitional implants retrieved after 2 months from posterior human maxillae. Methods: Twelve totally edentulous individuals (mean age, 66.14 ± 2.11 years) received DLMF transitional implants divided in twelve immediately loaded (IL) and twelve unloaded (UI) implants. These transitional implants were placed between conventional implants to support the interim complete maxillary denture during the healing period. After 8 weeks, the transitional implants and the surrounding tissue were removed and prepared for histomorphometric analysis. Results: Mature woven preexisting bone lined by newly formed bone in early stages of maturation were found around all retrieved implants. Histometric evaluation indicated that the mean BIC% was 45.20 ± 7.68% and 34.10 ± 7.85% for IL and UI, respectively (P <0.05). Conclusion: The present data obtained in humans showed that, although both IL and UI presented good BIC%, IL DLMF implants had a higher BIC% in the posterior maxilla.     

A 4‐ to 5‐Year Retrospective Clinical and Radiographic Study of Neoss Implants Placed with or without GBR Procedures

Background: New dental implant systems are continuously introduced to the market. It is important that clinicians report their experiences with these implants when used in different situations. Aim: The study aims to report the outcomes from a retrospective study on Neoss implants when used with or without guided bone regeneration (GBR) procedures. Materials and Methods: The study group comprised of 50 consecutive patients previously treated with 183 Neoss implants (Neoss Ltd., Harrogate, UK) in 53 sites because of single, partial, or total tooth loss. Implants were placed in healed bone in 23 sites, while a GBR procedure was used in 30 sites in conjunction with implant placement. A healing period of 3 to 6 months was utilized in 45 sites and in 8 sites a crown/bridge was fitted within a few days for immediate/early function. The number of failures, withdrawn and dropout implants was analyzed in a life‐table. All available intraoral radiographs from baseline and annual check‐ups were analyzed with regard to marginal bone level and bone loss. Results: A cumulative survival rate (CSR) of 98.2% was found for the non‐GBR group and 93.5% for the GBR group with an overall CSR of 95.0% after up to 5 years of loading. In spite of the failures, all patients received and maintained their prostheses. Based on all available radiographs, the bone level was situated 1.3 ± 0.8 mm (n = 159) below the top of the collar at baseline and 1.7 ± 0.8 mm (n = 60) after 5 years of follow‐up. Based on paired baseline and 1‐year (n = 70) and 5‐year radiographs (n = 59), the bone loss was found to be 0.4 ± 0.9 and 0.4 ± 0.9 mm, respectively. There were no statistically significant differences between GBR and non‐GBR sites with regard to implant survival or bone loss. Conclusions: The Neoss implant system showed good clinical and radiographic results after up to 5 years in function.