Effectiveness of manual and rotary instrumentation techniques for cleaning flattened root canals.

The cleaning capacity of manual and rotary instrumentation techniques in mesial-distal flattened canals was studied by morphometric analysis. Twenty human mandibular incisors were divided into two groups of 10 teeth each: group 1, crown-down technique with rotary instrumentation using ProFile .04; group 2, crown-down technique with manual instrumentation using K-files. The teeth were evaluated with an optic microscope that was coupled to a computer to determine the percentage of root canal area with debris. The nonparametric Mann-Whitney U test showed a statistically significant difference at the level of 1% between the techniques. The manual technique was more efficient in cleaning mesial-distal flattened root canals than the rotary technique, although neither completely cleaned the root canal.