Bulge ductility of several occlusal contact measuring paper-based and plastic-based sheets

Articulating paper/film is a sheet strip that is coated with ink- or dye-containing wax and is used for marking occlusal contacts and monitoring the results. New types of occlusal film systems have been developed recently, which are capable of being computer-interfaced to identify the occlusal contact points and digitize the occlusal force. The mechanical ductility and thickness of these occlusal sheets constitute some of their important properties. The objective of this study was to evaluate seven different occlusal sheets and compare their bulge ductility and thickness. A custom-designed photo-sensing bulge tester was used. Three paper-based sheets (BAP, BET and SFA), two plastic-based sheets (ACF and AOS), and advanced systems (TSS and FDP) were tested. The specimen size was 20 mm square. Fifteen samples were tested for each material. The sheet film thickness with coated layers was as follows: BAP, 62 μm; BET, 46μm; SFA, 133 μm; ACF, 23 μm; AOS, 14 μm; TSS, 134 μm; and FDP, 82μm. Ductility (standard deviation) was as follows: BAP, 2.10 (0.006)%; BET, 2.14 (0.008)%; SFA, 5.19 (0.57)%; ACF, 8.68 (0.05)%; AOS, 5.61 (0.05)%; TSS, 16.26 (0.41)%; and FDP, 6.37 (0.09)%. One-way ANOVA analysis indicated that (1) there in no statistical difference between BAP and BET (p > 0.001), (2) there is a statistical difference (p < 0.001) among all the rest of the tested occlusal sheets, and (3) bulge ductility appears to be linearly related to film thickness, its correlation depending upon types of base materials.