Tomoko Osada, DMD, PhD, Takako Ishimoto, DMD, PhD, Takayuki Aoki, DMD, PhD, Yasunori Suzuki, DMD, PhD, Norio Takishin, DDS, PhD, Chikahiro Ohkubo, DMD, PhD, and Toshio Hosoi, DDS, PhD
Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan
Purpose: Resins for denture repair must have higher bending strengths and similar hardness compared to denture base resins. This study evaluated the bending strengths and hardness of autopolymerized acrylic resin applied using the brush-on technique.
Materials and Methods: Square resin rods (2x2x25 mm) and blocks (15x15x5 mm) were fabricated for measuring the bending strengths and hardness, respectively, of five autopolymerized resins (Unifast II, Unifast Trad, Provinice, Metafast, and Miky). Two procedures for applying the autopolymerized resins were tested in this study: the brush-on technique and the conventional mixing (monomer/polymer: 0.5 mL/g) technique. The bending strengths of the resins (crosshead speed: 5 mm/minute) were measured with a three-point bending test using autography. The Vickers hardness (1.96 N, 10 s) was also measured using a hardness tester according to JIS 6518. The data (n=5) were analyzed by ANOVA/Tukey’s test (α=0.05).
Results: There were no significant differences (p>0.05) for both bending strengths and hardness between the brush-on technique and the conventional mixing technique. The bending strengths of Unifast Trad were significantly greater than those of Miky (p>0.05). Unifast II had the greatest hardness among all the resins tested.
Conclusion: Although the monomer/polymer ratio for the brush-on technique was lower than for the conventional mixing technique, similar bending strengths and hardness values were found for both techniques.(Int Chin J Dent 2010; 10: 1-5.)
Key Words: autopolymerized acrylic resin, bending strength, brush-on technique, hardness