Quality of approximal surfaces of posterior restorations in primary molars

Abstract

Purpose: To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in primary molars. Methods: Occluso-mesial cavities in second primary artificial molars were randomly restored using different materials (Filtek Z500 or Filtek Bulk Fill composites or high-viscosity glass ionomer cement Ketac Universal) and different matrix system (Tofflemire, AutoMatrix, matrix band with ring, contoured sectional matrix) (n = 12). Proximal contact tightness was measured using a custom-made device in an Instron 3345, and proximal surface morphology and marginal adaptation were scored after digital scanning. Two-way ANOVA, Tukey and Fischer’s exact tests were performed (P < 0.05). Results: Proximal contact tightness values were significantly influenced by the restorative material (P < 0.05), the matrix system (P < 0.001), and their interaction (P < 0.01). Both resin composites showed statistically differences in proximal shape according to the matrix used to restore and exhibited overhanging margins. Ketac Universal restorations showed simi-lar morphology and gaps on the margins regardless of the matrix system. Conclusions: Overall, both composite restorations achieved tighter proximal contact than those restored with the high-viscosity glass ionomer cement. None of the matrix systems tested provided a convex seamless proximal morphology.