Penetration depth of monomer systems into acrylic resin denture teeth used as pontics

The ways of softening and dissolving the surface of acrylic resin denture teeth need to be specified to obtain more durable prosthetic treatments that include resin denture teeth.

The purpose of this study was to analyze the penetration depth of 4 monomer systems applied during different exposure times on the acrylic resin denture teeth used as pontics of directly fabricated fiber-reinforced composite fixed dental prostheses. The penetration depth contributes to the adhesion of the tooth to the adhesive resin.

Ninety-six specimens were divided into 3 groups according to the acrylic resin denture tooth used: Artic 8 (Heraeus Kultzer), experimental tooth (GC), and Vitapan (Vita). Each group was divided into 4 subgroups according to the monomer system used: methylmethacrylate (99%), composite primer, a flowable composite resin, and a photopolymerizing dimethacrylate resin. The 4 monomer systems were labeled with rhodamine B to determine their penetration depth into the acrylic resin denture teeth. After exposure times of 1, 5, 15, and 60 minutes, the monomers were photopolymerized for 5 minutes, with the exception of methylmethacrylate. The specimens were cut orthogonally from gingival to occlusal in 4 slices (n=8/subgroup). The penetration depths of monomers were measured by a confocal scanning type microscope. Differences in the penetration depths were evaluated with ANOVA.

ANOVA (R(2)=.699) revealed significant differences in the penetration depths according to the exposure times (P<.001), monomers (P<.001), brands used (P=.047), and their mutual interaction (P<.001).

The ability of monomers to penetrate the surface of acrylic resin denture teeth was influenced by the monomer systems, which might improve the bond between the pontics and the fiber-reinforced composite frameworks of fixed dental prostheses.