Relation between Handling Characteristics and Application Time of Four Photo-polymerized Resin Composites

Objective: To investigate the relation between handling characteristics and application time of four composite materials with subjectively different viscosities. Methods: Eight experienced faculty members placed one Class II and one Class IV restoration in a random sequence into pre-prepared plastic teeth mounted on a typodont model, each using 4 types of composites (Herculite Précis (M1), Kerr; Tertic N-Ceram (M2), Ivoclar Vivadent; Filtek Z350 (M3), 3M-ESPE; Charisma Opal (M4), HareausKulzer), resulting in a total of 64 restorations. The application process was filmed with a high definition video camera. Two evaluators watched the recordings in a random sequence as well, timed the composite application and wrote down their observations, which were dichotimised into positive and negative ones. Application times were analysed with a two-way Kruskal Wallis test (time x dentist) and the observation data were analysed with a chi-square test (P 0.05). Results: Materials did not differ in their application time (P > 0.05). The mean application time was 12 ¼ minutes for the Class II and 9 ¾ minutes for Class IV restorations. However, there were statistically significant differences between the dentists in terms of application time. The observation data showed no significant difference between Class II and Class IV restorations but there were significant material differences (P 0.05). M2 yielded 6% negative observations, while the other materials were between 35% and 38%. Conclusion: There was no association between the handling characteristics of the tested composite resins and the speed of application. However, one of the tested materials (M2) showed significantly less problems in the application process. Keywords: Composite direct application, handling, observation study, in vitro, viscosity