Effect of plasma arc curing on the microleakage of Class V resin-based composite restorations

To evaluate the effect of plasma arc light-curing on the microleakage of Class V resin-based composite (RBC).

Facial and lingual Class V cavities were prepared at the cemento-enamel junction of extracted third molars. Restorations of the two materials (Z250; Amelogen) were placed, using the supplied dentin adhesives (Single Bond; PQ 1, respectively), and light-cured by either a halogen light curing unit (H) or a plasma arc curing unit (P). After thermal cycling, the teeth were immersed in methylene blue dye, then sections of the restored teeth were visually assessed for leakage.

No leakage was observed at the interface between enamel and RBC in any restoration in this study. At gingival margins, the incidence of leakage (slight/severe) was: Z250 H = 2/4, P = 6/6; Amelogen H = 3/4, P = 1/12, where n = 16. The greatest incidence of leakage was observed in restorations cured by the plasma arc method. A two-way ANOVA of leakage data rankings showed curing method to be a significant factor (P = 0.002), restorative material not to be a significant factor (P = 0.24), and no significant interaction between material and curing method (P = 0.38).