Longevity of posterior restorations in primary teeth: results from a paediatric dental clinic

The aim of this retrospective study was to evaluate the longevity of restorations in the posterior primary teeth of children attending to a public paediatric dental clinic and to test the factors associated with failures.

Patient records of 329 children (162 boys and 166 girls) were used for collecting and analyzing data. A total of 565 restorations in primary teeth were included in the study. All children enrolled in the study were classified as high caries risk. The longevity of restorations from their placement until failure (up to 4 years of follow-up) was assessed using the Kaplan-Meier survival curves with log-rank test. Multivariate Cox regression analysis with shared frailty (p<0.05) was used to assess the factors associated with failures.

Up to 4 years of follow-up, the annual failure rates were 9.5% for composite fillings, 12.2% for light-cured glass ionomer restorations, and 12.9% for conventional glass ionomer restorations with statistical difference between the materials (p=0.014). Glass ionomer restorations had a higher risk of failure over time compared with composites (HR 1.86, 95% CI 1.17-2.97). In crude analysis, Class II restorations showed lower survival rate than Class I restorations (p=0.031) but lost significance after adjustments.

Our findings suggested that the material influenced the survival rate of primary posterior restorations, with composite presenting the best performance.

Differences were observed between restorative materials with different properties in primary teeth up to 4 years of follow-up. This study provides valuable information regarding the primary teeth posterior restoration longevity in a paediatric population with restorations performed under daily life clinical environment.