Measurement of interfacial porosity at the acrylic resin/denture tooth interface

Small pores of almost uniform shape and size are common in polymeric materials; however, significant porosity can weaken a denture base resin and promote staining, harboring of organisms such as Candida albicans, and bond failures between the artificial tooth and denture base resin. The aim of this study was to investigate the porosity at the interface of one artificial tooth acrylic resin (Trilux, copolymer of polymethyl methacrylate, ethylene glycol dimethacrylate, and color pigments) and three denture base resins: Acron MC (microwave-polymerized), Lucitone 550 (heat-polymerized), and QC-20 (heat-polymerized).

Ten specimens of each denture base resin with artificial tooth were processed. After polymerization, specimens were polished and observed under a microscope at 80x magnification. The area of each pore present between artificial tooth and denture base resin was measured using computer software, and the total area of pores per surface was calculated in millimeter square. The Kruskal-Wallis test was performed to compare porosity data (alpha= 0.05).

Porosity analysis revealed the average number of pores (n), area range (S, mm(2)), and diameter range (d, mum) for Acron MC (n = 23, S = 0.001 to 0.0056, d = 35 to 267), Lucitone 550 (n = 13, S = 0.001 to 0.005, d = 35 to 79), and QC-20 (n = 19, S = 0.001 to 0.014, d = 35 to 133). The analyses showed that there were no statistically significant differences among the groups (p= 0.7904).

Within the limitations of this in vitro study, it was concluded that the denture base resins evaluated did not affect porosity formation at the artificial tooth/denture base resin interface.