QUANTITATIVE RADIOGRAPHIC FOLLOW-UP OF APICAL SURGERY - A RADIOMETRICAND HISTOLOGIC CORRELATION

The objective of this study was to establish an objective method for e valuating the treatment outcome of apical periodontitis (AP), AP was i nduced in the mandibular premolars of beagle dogs and apicoectomies we re performed with retrofilling. Standardized periapical radiographs we re taken immediately after completion of treatment and at 6 months. Te n pairs of standardized radiographs of 33 treated roots were analyzed, Radiographs were digitized and subtracted after warping and gamma cor rection. Areas of AP and adjacent normal areas (N) in digitized origin al and subtraction images were analyzed using eight radiometric comput ations. These computations were compared with subjective histologic ev aluation and objective quantitative histomorphometry of the periapical condition at 6 months, The average gray value for AP on the subtracti on images was found to have significant correlation with both objectiv e (multiple regression p < 0.01) and subjective histology (logistic re gression p < 0.01), Digital subtraction may be a useful tool in endodo ntic apical surgery assessment.