Bacterial Contamination of the Internal Cavity of Dental Implants After Application of Disinfectant or Sealant Agents Under Cyclic Loading In Vitro.

The aim of this in vitro study was to evaluate the influence of two sealants (Kiero Seal, Kuss Dental, and Berutemp 500, Carl-Bechem) and a disinfectant agent (Chlorhexamed gel, GlaxoSmithKline) on bacterial colonization of the implant-abutment interface. Implants were pretreated with the substances or left without sealing before standard abutments were fixed. Half the specimens were subjected to cyclic loading, and the others were not loaded. Following 7 days of incubation in a bacterial solution, bacterial counts of the internal part of the implants were determined by real-time polymerase chain reaction. All pretreatments lowered bacterial counts, but no substance could guarantee sterility of the implants' internal portion.

Transfer of Bacteria into the Internal Cavity of Dental Implants After Application of Disinfectant or Sealant Agents In Vitro.

PURPOSE: Bacterial colonization of the inner part of dental implants has been reported in numerous studies. The aim of this in vitro study was to analyze the bacterial colonization of the implant lumen of two implant systems that were partly subjected to a thermal cycling regimen after three different approaches to reducing bacterial load: filling of the hollow parts with either a disinfectant agent, a setting sealing compound, or a nonsetting sealing compound. MATERIALS AND METHODS: Two implant systems with internal connections (the Bego Semados RI implant, Bego, and the Xive S Plus Screw Implant, Dentsply) were used in this study. Before the corresponding abutments were fixed, the internal cavities were pretreated in four different ways (application of a 0.2% chlorhexidine gel, a special silicone, or a sealing grease, or no pretreatment). Half of the specimens were subjected to thermocycling. After incubation of the assemblies in a bacterial suspension of Escherichia coli for 1 week, the abutments were removed, and microbial samples of the internal aspects were collected; contamination was evaluated with quantitative realtime polymerase chain reaction (PCR). RESULTS: No pretreatment could hinder bacterial leakage in all cases, but all applied agents could reduce bacterial burden significantly (P < .05). There was less bacterial colonization after thermocycling (P < .05), and the Xive implants showed better resistance against microbial contamination (P < .05). CONCLUSION: The application of products to reduce bacterial invasion can help reduce bacterial load to a minimum and therefore can be helpful in minimizing the cofactors that contribute to the development of peri-implantitis.

Treatment Outcomes of Cantilever Fixed Partial Dentures on Vital Abutment Teeth: A Retrospective Analysis.

PURPOSE: This retrospective clinical study evaluated the long-term outcomes of cantilever fixed partial dentures (CFPDs) and the factors influencing their survival probability. MATERIALS AND METHODS: The study is based on a convenience sample of 57 patients who received 71 CFPDs on a total of 176 vital abutment teeth. The mean survival time of the CFPDs was calculated using a Kaplan-Meier estimate. The following variables were analyzed as covariates of the survival function (logrank test, P < .05): sex, denture location, number and distribution (Kennedy Class) of the abutment teeth, dentition in the opposing arch (removable dentures, fixed partial dentures, or natural dentition), position of the cantilever unit (mesial or distal), and participation in follow-up visits. RESULTS: The mean observation period was 3.2 ± 2.8 years (maximum 10.7 years). During the observation period, 22.5% (n = 16) of the CFPDs ceased functioning. The calculated outcome probability was 93.0% after 5 years and 84.5% after 8 years. The number of abutment teeth was the only parameter that significantly (P < .05) impacted this probability. CONCLUSION: The survival rate of CFPDs on vital abutment teeth is comparable to that of conventional fixed partial dentures. Thus, CFPDs on vital abutments are an acceptable alternative to removable dentures.

Three-Year Analysis of Fixed and Removable Telescopic Attachment-Retained Implant-Supported Dental Prostheses: Survival and Need for Maintenance.

PURPOSE: The purpose of this retrospective clinical study was to evaluate the clinical outcomes of fixed implant-supported dental prostheses (FISDPs) and removable ISDPs (RISDPs) retained by telescopic attachments, the factors influencing survival, and the type and number of maintenance treatments required during the observation period. MATERIALS AND METHODS: This retrospective clinical study is based on patients who were provided with ISDPs between 2004 and 2010. Patient sex, type of prosthesis, location, opposing dentition, and the effect of continuous follow-up on the probability of a favorable outcome, as well as the number of maintenance treatments, were analyzed. A statistical analysis was performed using the Kaplan-Meier method. RESULTS: A sample of 233 patients with 157 FISDPs and 76 RISDPs supported by a total of 567 implants was randomized and included in the analysis. The mean observation period was 15.9 ± 15.4 months (maximum, 66.0 months). During the observation period, 3.9% of prostheses (7/157 FISDPs and 2/76 RISDPs) ceased to function and 2.3% of implants (13 implants) were lost. The mean survival time was 59.7 ± 2.3 months, with a survival probability of 90.2% after 3 years. Prostheses in the mandible showed significantly higher survival rates than those in the maxilla. Maintenance treatments had to be performed at an earlier stage for patients with RISDPs than for patients with FISDPs. In patients with a conventional removable prosthesis in the opposing arch, the time until maintenance was needed was significantly shorter. CONCLUSION: Within the limitations of a retrospective study, it can be concluded that the FISDPs and RISDPs show equally good survival rates after 3 years in function. RISDPs showed a greater and earlier need for maintenance treatments during the first years in function.

Tooth preparation for full-coverage restorations-a literature review.

OBJECTIVES: The objective of this review was to assess the current knowledge about tooth preparation for full-coverage restorations regarding the following aspects: biological parameters, preparation geometry, and technical conditions. METHODS: A systematic literature search was conducted using three electronic databases (MEDLINE, DIMDI, and Cochrane databases) in order to identify relevant citations; additionally, the process was augmented by a hand search. RESULTS: A number of 117 citations were relevant; 11 of these were reviews, 23 were clinical studies, 82 were in vitro investigations, and one was animal research. CONCLUSION: The basic form of a preparation has not changed substantially over the years, although new materials like all-ceramic systems have their own demands with regard to the details of the preparation's geometry. Estimating how much of the tooth structure can be removed without harming the tooth remains one of the biggest problems, if not the main difficulty, during tooth preparation. As the periodontal tissues may be affected by the restoration margin, a supragingival position of the margin should be preferred whenever possible. No finish line design has yet proven to be superior with regard to the marginal accuracy of the subsequent restoration. Instead, good detectability of the margin for the dental technician or intraoral scanning devices appears to be of primary importance in order to achieve a good fitting restoration. CLINICAL SIGNIFICANCE: A detailed look at the covered aspects regarding tooth preparations can help to improve clinical outcomes in daily practice.

Long-span fixed dental prostheses not meeting Ante's law: a retrospective analysis.

OBJECTIVES: The aim of this retrospective study was to evaluate the long-term outcomes of long-span fixed dental prostheses (LSFDPs) not meeting Ante's law. METHOD AND MATERIALS: This study is based on the data of 36 patients who received 41 LSFDPs. The mean survival time of the LSFDPs was calculated using the Kaplan-Meier technique. The influence of the factors (gender, localization, number of abutments, Kennedy Class, dentition of the opposing jaw) were analyzed (log-rank test and Cox regression; P < .05). RESULTS: During the observation period, 22.0% (n = 9) of the LSFDPs ceased to function. The calculated outcome probability after 3 years was 88.3%, and 57.4% after 5 years. The only significant difference in the mean survival time could be found in LSFDPs with two abutment teeth in comparison with LSFDPs with three and more abutment teeth. Although all of the patients were invited to an oral health and maintenance program regularly, only 13.8% attended. CONCLUSION: The results, taken together with data from the literature, indicate that the patient's compliance is a crucial factor in the successful implementation of a LSFDP, whereas other factors are of minor importance.