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

Purpose: To evaluate the effect of plasma are light-curing on the microleak age of Class V resin-based composite (RBC). Materials ann Methods: Facial a nd 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; PQ1, respec tively), and light-cured by either a halogen light curing unit (H) or a pla sma are curing unit (P). After thermal cycling, the teeth were immersed in methylene blue dye, then sections of the restored teeth were visually asses sed for leakage. Results: No leakage was observed at the interface between enamel and RBC in any restoration in this study. At gingival margins, the i ncidence 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 observ ed in restorations cured by the plasma are method. A two-way ANOVA of leaka ge 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 s ignificant interaction between material and curing method (P = 0.38).