In vitro evaluation of the influence of patency file in maintaining the working length

Abstract Objective This study aimed to evaluate the influence of patency file in maintaining the working lenght (WL) for the crown-down preparation using oscillating system in artificial canals of acrylic. Material and method Thirty acrylic cubes were divided: a) Group 1 (n=10): without patency file and it were prepared in CT (CT=16 mm); b) Group 2 (n=10): with the patency #10 K-file, patency length of 17 mm and it were prepared in CT; and c) Group 3 (n=10): without patency file, using a #10 K-file in 16 mm for recapitulation and it were prepared in CT. Distilled water was used as irrigating solution. The results were statistically analyzed by the Levene and the Kruskal-Wallis test (p≤0.05), where it observed the loss of WL after instrumentation in different approaches to patency file. Result The results showed a statistically significant difference between groups 1 and 3 compared to group 2, however the group 1 be compared in relation to these 3 showed statistical similarities. Group 2 was the one who saved the WL after instrumentation in 16 mm, while group 1 and 3 showed a loss of up to 2 mm WL. Conclusion It was concluded that the patency file at 1 mm beyond the WL was effective in maintaining its length during root canal preparation.