Patent ID: 7901210

Claim:
A rotary-file dental treatment device ( 1 ) that is driven by a motor ( 2 ), comprising: a means ( 3 , 18 ) for fixing a root canal position setting relative to the apex of a tooth, a means ( 4 ) for stopping the motor based on the position of the file ( 1 ) relative to said position setting, a first means ( 5 ) for measuring, and a first means ( 6 ) for calculating the remaining root canal length (L) between the file and the position setting, wherein the first means for calculating comprises second means ( 7 , 7 a , 7 b ) for calculating at least one value (D) derived from the remaining root canal length and third means ( 8 , 8 a , 8 b , 8 c , 8 d , 8 e ) for calculating, suitable for combining the derived value and the remaining root canal length, whereby the combination of the derived value and the root canal length by the first, second and third means for calculating ( 6 , 7 , 8 , 8 a , 8 b , 8 c , 8 d , 8 e ) control the means for stopping the motor so as to stop the rotation of the file in anticipation of the position setting.