Evaluation of microleakage in class V composite restorations using dye penetration and micro-CT

The aim of this study was the evaluation of microleakage in class V cavities using micro-CT imaging and dye penetration.

Sixty class V cavities were prepared, randomly divided into five groups (Adper Single Bond Plus (ASB), ExciTE (EX), iBond TE (ITE), Optibond Solo Plus (OSP), Prime & Bond NT (PB)) and restored with Venus Diamond. After thermocycling and dye penetration test with 50 wt% ammoniacal silver nitrate, eight samples per group were sectioned longitudinally and evaluated under a coaxial incident light microscope (enamel (E) and dentin (D) measurement in mm). The remaining samples were analyzed by counting voids in the coronal and cervical adhesive areas by means of micro-CT.

In dentin, no statistically significant difference in dye penetration was found. In enamel, OSP showed significant higher microleakage than all other adhesives (p < 0.001). Groups ITE, ASB, PB, and EX showed a significantly lower penetration depth in E than in D (p < 0.001). The results of the micro-CT examination in dentin are contrary to the findings of the microleakage evaluation. Regarding enamel, only group PB showed significant more voids than EX in enamel (p < 0.02). Within the adhesive groups, PB showed significantly more voids in E than in D (p < 0.04).

This test method must be optimized by developing a new leakage tracer for a better differentiation between hard tissues and dental materials.

The micro-CT is not yet a vulnerable tool to evaluate the marginal integrity of resin composites.