Análise comparativa ex vivo dos efeitos do preparo de canais curvos com diferentes sistemas rotatórios, por meio de tomografia computadorizada helicoidal / Ex vivo comparative analysis of the effects of root canal preparation with different rotary systems by helicoidal computerized tomography

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The aim of this study was to compare the time of preparation, canal transportation, direction of transportation, mean centering ratio, and the percentage of area increase of canals instrumented using three rotary systems, assessed by spiral computed tomography. Forty lower molars with completely formed apices, curvature angle = 20, and radius of curvature <10 mm, were selected and divided into a control group and three experimental groups, according to the rotary systems: ProTaper (Group 1), ProFile (Group 2) e ProSystem GT (Group 3). The teeth were embedded into transparent acrylic resin and scanned by spiral computed tomography. Shaping was performed by one operator and was completed with the instrument #30 at the working length. The preparation time was measured using a digital chronometer. The teeth were then scanned under the same conditions as the initial scan. The transportation was determined by measuring the shortest distance from the edge of canal to the periphery of the root (mesial and distal) before instrumentation, compared to the same measurements obtained from the instrumented images. Three sections from each tooth correlated to the apical, medium and cervical thirds were used. A negative result of the transportation meant that it has occurred to distal direction, while a positive result, to mesial direction. The mean centering ratio was calculated for each section using the ratio between differences of values obtained for transportation. Percentage of area increase was calculated by the difference of root canal area after and before shaping. Mean preparation time was 137.22 57.15. Group 3 presented the lowest result (89.45 15.76) compared with groups 2 (130.2 33.58), and 1 (192 56.15), respectively (p<.001). Mean transportation was 0.024 0.141 mm with no statistically significant difference between the groups. Most of the instrumented canals were transported toward the outside of the curve. Mean centering ratio was 0.50 0.27 with no statistically significant difference between groups and sections. Percentage of area increase was 76.90 42.27 % with no statistically significant difference between groups. The percentage of area increase for the cervical third was significantly greater than cervical and medium thirds (p<.05). In conclusion, less preparation time was observed for the ProSystem GT group; there were no differences regarding transportation, mean centering ratio and percentage of area increase between groups; the direction of transportation was, mainly, towards the outer aspect of the curvature; the cervical third presented the highest percentage of area increase; no correlation between transport and percentage of area increase regarding working length, angle and radius of curvature was observed.

ASSUNTO(S)

dentistry odontologia odontologia root canal tratamento title treatment endodontia título endodontics canal radicular

Documentos Relacionados