Oxygen-inhibited surface layers on Microfill Pontic.

Radical polymerization of composite resins is inhibited by oxygen. For Microfill Pontic, a self- and photo-curing resin cement, irradiation is proposed as a means to reduce the thickness of the oxygen-inhibited surface layer. The thickness of the layer was measured by a dial gauge technique on irradiated and non-irradiated specimens, to determine a possible effect of irradiation. The results indicate that the depth of inhibition is reduced by irradiation and that an irradiation time of 20 sec is sufficient to give the maximum reduction.