Application of Heatless Glass as a coating material for denture base-evaluation of denture retentive force

Heatless Glass (HG) was applied to the basal surface of dentures as a coating material. To evaluate the influence of this material on the retentive force of the dentures, the adhesive force of pairs of resin specimens (heat curing resin), metal specimens (Co-Cr alloy), and HG metal specimens (Co-Cr alloy coated with HG), using tap water or resting saliva as a medium was measured, and the following results were obtained. (i) The adhesive force of metal specimens coated with HG material was significantly larger (by 2.3-2.6 times) than that of resin materials (P < 0.001), and it was slightly lower (0.8-0.9 times) than that of metal specimens, showing no significant difference (P > 0.10). (ii) The adhesive force of specimens using tap water as a medium was approximately one-half to two-third of that of specimens using resting saliva as a medium. (iii) When resting saliva was used as the medium, the maximum difference in the adhesive force of the specimens among subjects was 1.7 times. (iv) These findings suggested that, from the perspective of adhesive force, HG coating material is suitable for application to the basal surface of dentures.