Persistent endodontic lesion due to complex cementodentinal tears in a maxillary central incisor--a case report

The cementodentinal tear is rarely detected by noninvasive procedures owing to its clinical picture simulating a root fracture or a periodontal or endodontic lesion. We present a case of complex cementodentinal tears in a 79-year-old woman who presented a repeated swelling at the labial mucosa of the left maxillary central incisor for 6 months. Periapical radiographs demonstrated a vertical radiolucent fracture line extending from the root apex along the mesial aspect of the root to near the middle portion of the root of the left maxillary central incisor. Because endodontic re-treatment failed to cure the disease, periapical surgery was performed, and 2 fractured U-shaped root fragments around the apical root surface were removed. Histologic examination showed that the 2 fractured root fragments were composed mainly of the dentin covered by a thin layer of the cementum and overlying periodontal ligament tissue, suggesting cementodentinal tears. A swelling recurred 8 months after the initial operation. Therefore, a second periapical surgery was performed. Although no obvious fracture line was observed around the root surface, the second surgery did not cure the disease, either. A persistent small swelling was noted at the alveolar mucosa of the affected tooth during the follow-up. We conclude that although a cementodentinal tear can be detected by a careful radiographic examination, its clinical outcome is not predictable by surgical removal only.     

A pilot study applying digital radiography for estimating ratio of supported single-root surface area

BACKGROUND: The prognosis of a tooth with periodontitis is affected by the amount of supporting bone. A key factor in retaining a tooth is the ratio of supported root surface. Currently, root surfaces cannot be accurately measured using conventional dental radiographs, which only measure the length of bone support on proximal surfaces. METHODS: Eight extracted, single-rooted teeth were 3-dimensionally digitized using a contact technique for true surface area measurements. Root length, projection area, and pixel values were then measured on digital radiographs. The accuracy of the ratio estimation of supported surface area from linear, area, and pixel values was calculated and compared. RESULTS: The mean error from linear estimation was 7.9%; the mean error from area estimation was 1.0%; and the mean error from pixel value estimation was 1.3%. One-way analysis of variance (ANOVA) showed significant differences in all estimations while Scheffé's analysis further revealed significant differences only in the linear estimation. CONCLUSIONS: A three-dimensional digitizing device could be used as a non-destructive method of measuring root surface area. The ratio of supported single-root surface area could be estimated with high accuracy from the projected area data acquired on the digital dental radiographs. The thickness data as reflected from the pixel values in the digital images did not improve the estimation accuracy. Estimations using only length data yielded significantly less accuracy. Digital dental x-ray images provide the potential for estimating the ratio of supported root surface efficiently.