Purpose: The discoloration of auto-polymerized resin has frequently been observed after denture repair. This study is an investigation of the discoloration of auto-polymerized resin applied using a brush-on technique.
Materials and Methods: Rectangular resin plates were fabricated so that five auto-polymerized resins (Unifast II, Unifast Trad, Provinice, Metafast, and Miky) could be packed in a mold (15x30x1 mm) using a brush-on technique (resin brush, horsehair) in six increments for each mold. As controls, the five resins were poured in the molds after the polymer and monomer were mixed at 0.5 mL/g for 10 s. After polymerization, half of the resin plates were covered with aluminum foil. All the plates were soaked in distilled water (37°C) and exposed to xenon light for 24 hours according to ISO 7491. They were soaked in water again for 5 days. After removing the aluminum foil, the discoloration was measured using a color difference meter (Shade eye system) three times for each specimen. The color differences (∆E: n=5) were analyzed by ANOVA/Tukey’s test (α=0.05).
Results: For the brush-on technique, Provinice had the greatest color change of any of the resins tested. There were significant differences between the brush-on technique and the controls for Unifast II and Miky.
Conclusion: The brush-on technique resulted in fewer color changes than the mixing technique on all resins except for Provinice, as shown by the fact that many porosities were found in the control specimens.

Purpose: The purpose of this study was to investigate knowledge about denture cleansers of dentists in Japan, China, and Indonesia.
Materials and Methods: Forty-three dentists from Japan (Hiroshima University), 26 dentists from China (Hebei Medical University and Wuhan University) and 62 dentists from Indonesia (Airlangga University) were surveyed by questionnaire about their knowledge and understanding of denture cleansers in this study.
Results: The response rate was 91.6%. Significant differences among the three countries were found for ten questions. For the question “Have you heard of denture cleansers?”, 100% of Japanese dentists answered “Yes”, whereas 19.2% of Chinese dentists and 14.5% of Indonesian dentists answered “No”. For the question “Have you ever seen denture cleansers in the clinic?”, more than 90% of subjects in Japan answered with “often” or “occasionally”, whereas 69.2% of Chinese dentists and 54.1% of Indonesian dentists answered “No”. For the question “Do you think the use of denture cleanser is more effective than a clinical intervention?”, over 90% of the subjects in Japan answered “Yes”; however, over 55% of subjects in China and over 65% of Indonesian subjects answered “No”.
Conclusion: The results suggest that dental professionals in China and Indonesia have little knowledge about denture cleansers. The study confirms that there is a difference in the interest and knowledge about denture cleansers among the three countries of Japan, China, and Indonesia.