[Accuracy of paralleling technique in measuring the depth of approximal infrabony pocket].

OBJECTIVE: To assess the accuracy of paralleling technique in measuring the depth of approximal infrabony pocket after periodontal flap surgery by comparing the measured and actual depths. METHODS: The study population included 26 patients with infrabony defects who had undergone periodontal flap surgery, bone graft surgery, and guided tissue regene-ration. The measured and actual depths of approximal infrabony pocket after periodontal flap surgery were compared. The 26 infrabony defects were categorized into the following groups according to tooth position: anterior teeth, premolar, and molar groups, and according to type of infrabony pocket: one-walled, two-walled, and three-walled infrabony pocket groups. Paired t-test was used to detect the difference between the two values. RESULTS: Depth measurements of the approximal infrabony pocket depth of the anterior teeth and premolar were not significantly different (P>0.05), whereas those of the molar group were significantly different (P<0.05). In addition, depth measurements in one-walled and two-walled infrabony pocket groups showed no significant differences (P>0.05), whereas those in the three-walled infrabony pocket group were significantly different (P<0.05). CONCLUSIONS: Paral-leling technique can accurately measure the depth of approximal infrabony pockets of anterior teeth and premolar teeth that are one- or two-walled. However, this method cannot accurately measure the approximal infrabony pockets of molar teeth and three-walled infrabony pockets as indicated by significant differences in their depth measurements.