Nondestructive evaluation of microleakage in restored primary teeth using CP-OCT

Although the demand for esthetic filling of primary teeth with resin composite is increasing, there is no enough data on the adhesive performance of composite restorations in primary teeth. Despite the improvements in resin composites, interfacial gap is still a disadvantage as it may cause marginal staining, secondary caries, and restoration failure. Previous studies have validated the efficiency of optical coherence tomography (OCT) in the evaluation of adhesive interface in permanent teeth, but not in primary teeth.

The aim of this study was to assess microleakage upon composite restorations in primary teeth using cross-polarization OCT (CP-OCT).

Cylindrical class-V cavities were prepared in extracted human primary second molars and divided into four groups randomly. In groups 1 and 2, cavities were restored using Tetric N-Universal adhesive in the self-etch mode followed by IPS Impress Direct Composite and Ceram.x One Universal composite, respectively. In groups 3 and 4, one-step self-etch Prime and Bond Elect adhesive was used followed by ID composite and CX composite in groups 3 and 4, respectively. The specimens were then immersed in a contrasting solution followed by interfacial microleakage examination under CP-OCT. The recorded images were analyzed to quantify the mean gap percentages.

All tested groups showed variable degree of interfacial microleakage under composite restorations. Two-way ANOVA showed the composite factor was significantly influencing the results, unlike the adhesive. Group 1 and 2 had the lowest and highest mean gap percentage, respectively, which were significantly different from the other groups. Groups 3 and 4 were not significantly different.

Based on the current finding, a polymeric restorative system from the same manufacturer reduces the risk of interfacial microleakage in primary teeth.