Periodontal healing after impacted lower third molar surgery. Precision and accuracy of radiographic assessment of intrabony defects.

The effect of periodontal tissues of impacted lower 3rd molar surgery has been investigated in a retrospective study comprising 215 cases, 2 years postoperatively. In order to evaluate the precision and accuracy of the radiographic assessment of intrabony defects on the distal surface of the lower 2nd molar using conventional free hand technique, a methodological study was performed on 25 patients. The error variance due to variability in the radiographic reproduction and examiner inconsistency was between 3 and 4% of the total variance. In order to evaluate the radiographic assessment of intrabony defects, intraoral radiographs were taken in the deepest part of the intrabony defect with and without a probe as an indicator. Comparing the 2 sets of radiographs, the deviation was 1 mm or less in 87.9% of the cases. The radiopaque marker enhanced the accuracy of assessment of intrabony defects to 96.7%. The study shows the intraoral freehand technique to be sufficiently reliable as regards radiographic reproduction of the mandibular molar area. It also demonstrates that the radiographic method describes the depth of postoperative intrabony defects on the distal surface of the lower 2nd molar more accurately than probing depth measurements alone.