Resumo

DRAGO, Mariana et al. Deformation of the outer surface of the Protaper® Universal files. RPG, Rev. pós-grad. [online]. 2011, vol.18, n.3, pp. 160-169. ISSN 0104-5695.

This study aimed to evaluate the type and location of the defects on the surface of rotary instruments before and after their use in the preparation of root canals in vitro. Forty human upper and lower molars were prepared with eight sets of rotary instruments ProTaper® Universal (Dentsply Maillefer, Switzerland), in constant speed of 350 rpm. The instruments were evaluated D0 to D3 to the scanning electron microscope (Superscan SS-550, Shimadzu, Japan) at three moments: Group A - before the use of the files; Group B - after the use of each set of instruments in the preparation of three teeth; Group C - for the same series of files to prepare over two molars. The surface changes were classified as braking marks, strips of metal, sharp edges and dips. Files descriptively analyzed before the instrumentation showed marks of braking and metal strips in the first and third millimeter. Dips were predominant in the second millimeter. At a second moment, braking marks, metal strips and dips were prevalent in the first millimeter. In a third moment, dips were present in every millimeter of each instrument studied. Files which suffered deformities were significant Sx, S1 and F1 in millimeter D0-D1; F3 and F4 in millimeter D1-D2; and F5 in millimeter D2-D3. The time did not affect the results. It is concluded that defects in the instruments were present on the surface of the files over the 3 mm in the study. With the instrumentation, the amount of lives that showed sharp edges and dips progressed.

Palavras-chave : Endodontics; Dental instruments; Dental pulp cavity.