Handling efficiency of autopolymerized resin applied using the brush-on technique

Yasunori Suzuki, DMD, PhD, Hikari Chiba, DMD, PhD, Natsuko Kamada, DMD, PhD, Daisuke Kurihara, DMD, PhD, Yukari Kanki, DMD, PhD, Yoshiya Miyama, CDT, Toshio Hosoi, DDS, PhD, and Chikahiro Ohkubo, DMD, PhD

Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan

Purpose: The brush-on technique is frequently used for applying autopolymerized resin during chairside denture repair and adjusting individual tooth trays. This study evaluated the handling efficiency of autopolymerized resin applied using this technique.
Materials and Methods: Five autopolymerized resins, Unifast II (GC), Unifast Trad (GC), Provinice (Shofu), Metafast (Sun Medical), and Miky (Nissin), were used in this study. Five operators (one dental technician, two dentists, and two dental students; ages 23-51) fabricated round resin pieces, approximately 6 mm in diameter, from the five autopolymerized resins on a pasteboard in one procedure. Four different brushes were tested; a calligraphy brush (cat hair, Naokatsu), two resin brushes (nylon fiber and horsehair, Seiundo), and a bristle brush (weasel hair, Shofu). After polymerization, the resin pieces were weighed on an electric balance. The handling behavior (n=5) was assessed by the coefficient of variation (%) of the weight and analyzed by ANOVA/Tukey’s test (α=0.05). After the test, all the operators completed a questionnaire about fabricating the resin pieces.
Results: Although significant differences were found among the operators (p<0.05), there were no significant differences among all the resins and brushes tested (p>0.05). However, the horsehair resin brush tended to have greater coefficients of variation. The results of the questionnaire indicated that Unifast II and the calligraphy brush were preferred by the operators.
Conclusion: The handling efficiency of the autopolymerized resin using the brush-on technique depended on the skill of the operators rather than the resins and brushes. (Int Chin J Dent 2009; 9: 33-38.)

Key Words: autopolymerized acrylic resin, brush-on technique, coefficient of variation, handling efficiency.