0 software (Corel Corporation, Berkshire, UK) One pixel of the c

0 software (Corel Corporation, Berkshire, UK). One pixel of the composite image represents 0.048 mm in real dimension. Distances between pre-operative and post-operative outer lines of the simulated canal were measured at 11 levels (0-10 mm) from the apical tip at the inner and outer sides of the curve compound library on the superimposed images to 0.01 mm accuracy. The amount of removed material and the symmetry of the preparation were evaluated. Statistical analyses were performed with Mann-Whitney U-test. RESULTS All statistical results for the two instrument systems are presented in Figures Figures11 and and22. Figure 1 (a) Average thickness of canal wall removal by the two instrument systems measured at 11 levels (P < 0.05). (b) Symmetry of the preparations made by the two instrument systems measured at 11 levels (P < 0.

05) Figure 2 Illustrations of the statistically significant results. (a) Amount of removed resin for the both two systems at 11 levels and (b) For preparation symmetry on the 11 levels (no significant difference between instruments; P < 0.05) For the inner curve, Mtwo removed significantly more material at 7 levels (4-10 mm) and the ProTaper at 1 level (0 mm) (P < 0.05). No significant difference between the systems was determined at 3 levels (1, 2, 3 mm). For the outer curve, Mtwo removed significantly more material at 2 levels (2, 3 mm) and ProTaper at 1 level (6 mm) (P < 0.05). No significant difference between the systems was determined at 8 levels (0, 1, 4, 5, 7, 8, 9, 10 mm). The preparations made with ProTaper were more symmetric at 4 levels (4, 5, 6, 7 mm, P < 0.

05) and no significant difference was determined at 7 levels (0, 1, 2, 3, 8, 9, 10 mm). DISCUSSION The term operator-related variable involves all factors related with the operator, such as ability, experience and proficiency. Those variables may affect the shape of a preparation and thus may also affect the results of the experiments. Thus, standardization of operator-related variables is a necessity to obtain more comparable results in experimental procedures. In a previous study,[12] we developed a computer-controlled device and by using this device and a torque- and speed-controlled electric motor, we tried to standardize the two main motions (rotary and pecking) in a rotary preparation process.

In this study, we used the same device and computer program to control and adjust the following parameters in both instrument groups: Total distance of vertical file movement in the canal, number and frequency of pecking motions, distance of file tip progression and penetration depth of the instruments at each procedure step and vertical linear motion speed of the handpiece. Nonetheless, the main limitations of the device Carfilzomib are its unsuitability for simulated instrumentation of extracted teeth and its applicability only in artificial canal blocks. It also cannot reproduce human judgment relevant in the clinical situation.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>