Depth of cure and marginal adaptation to dentin of xenon lamp polymerized resin composites

Marginal adaptation of four resin composites (Clearfil APX, Estelite, Silux Plus and Z-100) cured with two xenon lamp units (Plasma Arc Curing System or Apollo 95E) or a halogen lamp unit (Witelite) were evaluated by measuring the wall-to-wall contraction gap width. A cylindrical dentin cavity (ø3 mm x 1.5 mm) prepared in an extracted human molar was treated with the Megabond system or an experimental bonding system consisting of 0.5 M EDTA, 35% GM and Clearfil Photo Bond prior to composite filling and was irradiated for three seconds (xenon lamp) or 40 seconds (halogen lamp). The contraction gap was measured with a light microscope. In addition, the curing capability of these three light sources was evaluated by measuring the curing depth of the composites filled in a split Teflon mold (ø4 mm x 8 mm). There was no marginal gap formation for Clearfil APX, Estelite and Silux Plus treated with the experimental bonding system regardless of the type of light sources. The curing depth of the xenon lamp was significantly higher than the halogen lamp, while marginal adaptation did not suffer any significant deterioration.