Repeatability and accuracy of a paralleling technique for radiographic evaluation of distal bone healing after impacted third molar surgery

Objectives

The purpose of this study was to investigate the repeatability and radiographic accuracy of an intraoral paralleling technique to evaluate periodontal bone healing on the distal surface of the second mandibular molar (2 Mm) after impacted third mandibular molar (3 Mm) surgical extraction.

Methods

In order to estimate the variation in different radiographs, three replicas were made, each from 2 Mm, totalling 69 radiographic radicular longitude (RRL) recordings. One operator performed the periapical radiographs in a standard manner, utilizing a modified posterior film holder for the radiographic technique of parallelism, applied on the posterior region with the X-ray beam focused on the centre of 2 Mm. These radiographic recordings of the same region were obtained on three different and separate occasions, over a 12 month evaluation period after surgical extraction of the impacted 3 Mm. The RRL variable was measured and recorded three times by the same operator, with side-by-side comparison of three posterior periapical radiographs, irrespective of when the assessments were performed.

Results

There were no statistically significant differences between the three replica recordings (p = 0.969). The correlations between the three sets of measurements were evaluated and found to be highly associated (intraclass correlation reliability coefficient = 0.90) and statistically significant (p≤0.05). The median and mean error of the radiographic technique evaluated was ±0.257 mm and ±0.347 mm, respectively.

Conclusions

The radiographic technique described permits standardization in periapical radiographs with a high repeatability and accuracy in posterior radiographic records (distal surface of 2 Mm) over a postoperative evaluation period of 12 months.