Delano E O, Tyndall D, Ludlow J B, Trope M, Lost C
Diagnostic Sciences Department, University of North Carolina School of Dentistry, Chapel Hill 27599-7450, USA.
J Endod. 1998 Jun;24(6):420-6. doi: 10.1016/S0099-2399(98)80025-3.
The objective of this study was to establish an objective method for evaluating the treatment outcome of apical periodontitis (AP). AP was induced in the mandibular premolars of beagle dogs and apicoectomies were performed with retrofilling. Standardized periapical radiographs were taken immediately after completion of treatment and at 6 months. Ten pairs of standardized radiographs of 33 treated roots were analyzed. Radiographs were digitized and subtracted after warping and gamma correction. Areas of AP and adjacent normal areas (N) in digitized original and subtraction images were analyzed using eight radiometric computations. These computations were compared with subjective histologic evaluation and objective quantitative histomorphometry of the periapical condition at 6 months. The average gray value for AP on the subtraction images was found to have significant correlation with both objective (multiple regression p < 0.01) and subjective histology (logistic regression p < 0.01). Digital subtraction may be a useful tool in endodontic apical surgery assessment.
本研究的目的是建立一种评估根尖周炎（AP）治疗效果的客观方法。在比格犬的下颌前磨牙诱导根尖周炎，并进行根尖切除术及倒充填。治疗完成后立即及6个月时拍摄标准化根尖片。对33颗治疗牙根的10组标准化根尖片进行分析。根尖片数字化后经变形和伽马校正进行相减。使用八种放射测量计算方法分析数字化原始图像和相减图像中根尖周炎区域及相邻正常区域（N）。将这些计算结果与6个月时根尖周状况的主观组织学评估和客观定量组织形态计量学进行比较。发现相减图像上根尖周炎的平均灰度值与客观（多元回归p<0.01）和主观组织学（逻辑回归p<0.01）均具有显著相关性。数字相减可能是牙髓根尖手术评估中的一种有用工具。
