Rubber dam isolation increases the costs and does not impact on composite resin restorations’ survival in primary teeth. 2-year results from a non-inferiority clinical trial

Abstract Background This non-inferiority randomised trial aimed to evaluate the survival rate, costs and discomfort/behaviour of two operative field isolation methods. Methods A total of 93 4–8 years old children (174 molars) with at least one dentine caries lesion were randomly allocated to groups: rubber dam isolation (RDI) and cotton roll isolation (CRI), restored with bulk fill composite resin. Two blinded examiners assessed the restorations up to 24 months. Wong-baker faces, and Frankl’s behaviour rating scales were used for accessing child’s discomfort and behaviour, respectively. For the statistical analysis, the primary outcome (restoration survival) used two-sample non-inferiority test for survival data using Cox Regression, Bootstrap Linear regression analysis for cost analysis and logistic regression for discomfort and behaviour. Results 157 restorations were evaluated (drop-out = 9.7%). Survival was RDI = 60.4% and CRI = 54.3. The non-inferiority hypothesis was accepted by the Cox Regression analysis (HR = 1.33; 90% CI 0.88–1.99; p = 0.036). RDI was 53% more expensive when compared to the CRI group. No differences were found between the groups in terms of discomfort and behaviour. Conclusion Cotton roll isolation proved to be non-inferior when compared to rubber dam for composite restorations longevity in primary molars. Furthermore, the latest presented the disadvantage of higher cost and longer procedure time. Clinical Significance: Rubber dam isolation has no impact on the survival of composite restoration in primary molars. Clinical trial registration: registered NCT03733522 on 07/11/2018. The present trial was nested within another clinical trial, the CARies DEtection in Children (CARDEC-03 - NCT03520309).