The present study aimed to evaluate the morphology and mechanical properties of two orifice openers produced by the same manufacturer, with the same design and heat treatment but different dimensions. Twenty I-File/Onyx Orifice Openers for each of the following sizes (09.09 versus 20.07) were selected for the study. The instruments were initially examined with SEM at x200 and measured to ensure dimensional accuracy. Then they were randomly divided into two identical groups (n=10). For each size, one group was tested for cyclic fatigue and the other for ISO torsional resistance, using methods already validated in the authors’ previous studies (16-20). The same expert operator performed each test to minimize errors caused by differences in operator skill. For each size and test, 10 instruments were analyzed for each brand. The data were collected and statistically analyzed using 1-way ANOVA followed by a post hoc Tukey test at the 95% confidence level. The D0 diameters showed very good dimensional accuracy, with small standard deviations and mean values compatible with ISO dimensional tolerance (0.02). No significant statistical differences were noted between the two groups for maximum torque at failure (TAF) (P>0.05). In contrast, significant differences were noted for the deflection angle and resistance to cyclic fatigue (P<0.05). In both cases, the 09.09 orifice opener performed better. The newly developed 09.09 orifice opener showed very interesting mechanical properties compared with a more traditional orifice opener, suggesting its possible routine use, with the majority of benefits in more complex cases. The present study also showed precise manufacturing despite a very small tip size and a heat treatment.
Bago Ivona (Thu,) studied this question.