The Timing of Subsequent Treatment for Teeth Restored with Large Amalgams and Crowns: Factors Related to the Need for Subsequent Treatment

Treatment recommendations for single-unit crowns: Findings from The National Dental Practice-Based Research Network

BACKGROUND

The objectives of this study were to quantify practitioner variation in likelihood to recommend a crown and test whether certain dentist, practice, and clinical factors are associated significantly with this likelihood.

METHODS

Dentists in The National Dental Practice-Based Research Network completed a questionnaire about indications for single-unit crowns. In 4 clinical scenarios, practitioners ranked their likelihood of recommending a single-unit crown. The authors used these responses to calculate a dentist-specific crown factor (range, 0-12). A higher score implied a higher likelihood of recommending a crown. The authors tested certain characteristics for statistically significant associations with the crown factor.

RESULTS

A total of 1,777 of 2,132 eligible dentists (83%) responded. Practitioners were most likely to recommend crowns for teeth that were fractured, cracked, or endodontically treated or had a broken restoration. Practitioners overwhelmingly recommended crowns for posterior teeth treated endodontically (94%). Practice owners, practitioners in the Southwest, and practitioners with a balanced workload were more likely to recommend crowns, as were practitioners who used optical scanners for digital impressions.

CONCLUSIONS

There is substantial variation in the likelihood of recommending a crown. Although consensus exists in some areas (posterior endodontic treatment), variation dominates in others (size of an existing restoration). Recommendations varied according to type of practice, network region, practice busyness, patient insurance status, and use of optical scanners.

PRACTICAL IMPLICATIONS

Recommendations for crowns may be influenced by factors unrelated to tooth and patient variables. A concern for tooth fracture-whether from endodontic treatment, fractured teeth, or large restorations-prompted many clinicians to recommend crowns.

A Bayesian analysis of amalgam restorations in the Royal Air Force using the counting process approach with nested frailty effects

Survival analysis methods are increasingly used in dental research to measure risk of tooth eruption and caries as well as life spans of amalgam restorations. Analyses have been extended to account for lack of independence in the data, which arises from the clustering of observations within units such as tooth-surfaces, teeth and subjects. There are various analytical strategies and modelling approaches now available to us in dealing with clustered dental data. In this article, the modelling strategy of Cox’s proportional hazards regression is formulated using the counting process approach, which can easily be extended to include time-variant covariates as well as nested random frailty effects. A semi-parametric Bayesian method is presented for the analysis of the proposed model. The methodology is applied to an analysis of nested clustered data on life-span of amalgam restorations in the UK Royal Air Force. These data have previously been analysed using a non-Bayesian approach. The Gibbs sampler, a Markov chain Monte Carlo method, is used to generate samples from the marginal posterior distribution of the parameters of this Bayesian model.

Survival and reasons for failure of amalgam versus composite posterior restorations placed in a randomized clinical trial

BACKGROUND

Failure of dental restorations is a major concern in dental practice. Replacement of failed restorations constitutes the majority of operative work. Clinicians should be aware of the longevity of, and likely reasons for the failure of, direct posterior restorations. In a long-term, randomized clinical trial, the authors compared the longevity of amalgam and composite. SUBJECTS, METHODS AND MATERIALS: The authors randomly assigned one-half of the 472 subjects, whose age ranged from 8 through 12 years, to receive amalgam restorations in posterior teeth and the other one-half to receive resin-based composite restorations. Study dentists saw subjects annually to conduct follow-up oral examinations and take bitewing radiographs. Restorations needing replacement were failures. The dentists recorded differential reasons for restoration failure.

RESULTS

Subjects received a total of 1,748 restorations at baseline, which the authors followed for up to seven years. Overall, 10.1 percent of the baseline restorations failed. The survival rate of the amalgam restorations was 94.4 percent; that of composite restorations was 85.5 percent. Annual failure rates ranged from 0.16 to 2.83 percent for amalgam restorations and from 0.94 to 9.43 percent for composite restorations. Secondary caries was the main reason for failure in both materials. Risk of secondary caries was 3.5 times greater in the composite group.

CONCLUSION

Amalgam restorations performed better than did composite restorations. The difference in performance was accentuated in large restorations and in those with more than three surfaces involved.

CLINICAL IMPLICATIONS

Use of amalgam appears to be preferable to use of composites in multisurface restorations of large posterior teeth if longevity is the primary criterion in material selection.

Risk factors for failure of glass fiber-reinforced composite post restorations: a prospective observational clinical study

Glass fiber-reinforced endodontic posts are considered to have favorable mechanical properties for the reconstruction of endodontically treated teeth. The aim of the present investigation was to evaluate the survival of two tapered and one parallel-sided glass fiber-reinforced endodontic post systems in teeth with different stages of hard tissue loss and to identify risk factors for restoration failure. One-hundred and forty-nine glass fiber-reinforced endodontic posts in 122 patients were followed-up for 5-56 months [mean +/- standard deviation (SD): 39 +/- 11 months]. Glass fiber-reinforced endodontic posts were adhesively luted and the core was built with a composite resin. Cox proportional hazards models were used to evaluate the association of clinical variables and failure rate. Higher failure rates were found for restorations of anterior teeth compared with posterior teeth [Hazard-Ratios (HR): 3.1; 95% confidence interval (CI): 1.3-7.4], for restorations in teeth with no proximal contacts compared with at least one proximal contact (HR: 3.0; 95% CI: 1.0-9.0), and for teeth restored with single crowns compared with fixed bridges (HR: 4.3; 95% CI: 1.1-16.2). Tooth type, type of final restoration and the presence of adjacent teeth were found to be significant predictors of failure rates in endodontically treated teeth restored with glass fiber-reinforced endodontic posts.

Teeth with large amalgam restorations and crowns

BACKGROUND

The authors evaluated the factors associated with the receipt of subsequent treatment by teeth restored with a large amalgam restoration or a large amalgam restoration and crown restoration after 10 years.

METHODS

The authors used retrospective data from the University of Iowa College of Dentistry (Iowa City, Iowa) administrative database and patient records to evaluate patient and tooth factors for their association with the two primary outcomes: receipt of any subsequent treatment and receipt of catastrophic treatment (extraction, endodontic therapy).

RESULTS

The authors followed 518 teeth over a 10-year period (49 percent with large amalgam restorations and 51 percent with crowns). Sixty-four percent of the large amalgam restorations and 32 percent of the crowns received subsequent treatment during the 10 years. In addition to restoration type, the patient's sex, history of grinding teeth and having a broken tooth were related to the tooth's receiving subsequent treatment. Twenty-two percent of large amalgam restorations and 12 percent of crowns received catastrophic treatment with the odds of teeth with large amalgam restorations receiving a catastrophic treatment being 2.1 times the odds of teeth with crowns receiving catastrophic treatment.

CONCLUSIONS

Teeth with crowns were less likely to receive any treatment or catastrophic treatment over 10 years than were teeth with large amalgam restorations. Patient and tooth factors also were related to a tooth experiencing subsequent treatment.

CLINICAL IMPLICATIONS

Teeth with crowns received less subsequent treatment than teeth with large amalgam restorations. This could be related to both the difference in longevity between the two restorations, as well as how appropriately treatment was planned for each procedure. Cost differences between the two restorations need to be factored into the decision-making process.