Effect of surface treatment agents on bond strength of auto-polymerized acrylic resin to poly(ethylene terephthalate)

Eiji Miura, DDS, PhD,(a) Yasuko Takayama, DMD, PhD,(a) Yukihiro Mizuno,(b) Minoru Abe, DDS, PhD,(a) Yoshiyuki Kawai, DDS, PhD,(a) and Chikahiro Ohkubo, DMD, PhD(a)

(a)Department of Removable Prosthodontics, and (b)Dental Technician Training Institute, Tsurumi University School of Dental Medicine, Yokohama, Japan

Purpose: This study evaluated the adhesive strength between a thermoplastic poly(ethylene terephthalate) (PET) sheet and an auto-polymerized acrylic resin (Unifast III).
Materials and Methods: The shear bond strength of auto-polymerized acrylic resin to PET with or without surface treatment was measured. Four surface treatment agents, Unifast III Liquid, Resin Primer, Adhesive, and GP Solvent, were used.
Results: The shear bond strengths were 28.8 MPa for GP Solvent, 26.5 MPa for Resin Primer, 24.6 MPa for Adhesive, 24.4 MPa for the untreated control, and 23.4 for Unifast III Liquid. Significant differences were found between the control and GP Solvent, between Unifast III Liquid and GP Solvent, and between Adhesive and GP Solvent (p<0.05). SEM observation showed that the surfaces of the thermoplastic sheets had dissolved due to the application of Unifast III Liquid, Adhesive, and Resin Primer.
Conclusion: Specimens treated with GP Solvent, Resin Primer, and Adhesive exhibited higher bond strength value compared to the control specimens. GP Solvent had the highest adhesive strength. SEM observation indicated that the surface changes of the PET treated with Resin Primer were the most remarkable. (Int Chin J Dent 2010; 10: 57-62.)

Key Words: auto-polymerized acrylic resin, poly(ethylene terephthalate), shear bond strength, surface treatment agent, thermoplastic sheet