Discussion
In this case of a 75-year-old patient, pulp vital testing, measurement of periodontal pocket depth, and CBCT provided an accurate diagnosis of a cemental tear with severe periodontitis at #25, and a sinus tract at the labial gingiva was found to be caused by periodontal inflammation due to the cemental tear, but without endodontic disease. In addition, the patient had healthy periodontal tissue. These findings can support that cemental tear is one of the causes of periodontal abscess in non-periodontitis patients (14, 15).
According to the new classification that consists of Class (0 to 6), Stage (A, B, C, and D), and treatment decision-making and selection for cemental tears (2), this case was classified as Class 3/Stage C, and the regeneration approach with rhFGF-2, which can effectively regenerate periodontal tissue in patients who suffer from periodontal disease (16-18), was applied. Bacteria invade the concealed site of the fractured fragments of a cemental tear and scattered cemental fragments within the granulomatous tissues to colonize, proliferate, and survive (13). A dental operating microscope is essential to improve access to the operative field and to facilitate complete removal of torn cemental fragments and granulation tissue during the operation (2). Therefore, in this case, a surgical approach was adopted using a dental operating microscope.
In this case, the labial bone defect was regenerated to the position of the crest of lingual bone, showing successful clinical and radiographic outcomes. In our previous case of a cemental tear with root-canal perforation into the labial site, chronic apical periodontitis, a severe loss of labial bone, and a proximal bone defect at the middle third of the root in #25, significant PD reduction, CAL gain, and proximal bone regeneration were obtained after perforation repair, root canal treatment, and periodontal treatment including periodontal regeneration therapy, although bone regeneration at the labial site was not observed (13). The tooth-root states differed between our previous report (13) and the present report in periodontal regeneration therapy, as follows. In the previous case, #25 had an obturated root canal, perforation repair, and a large wedge-shaped defect at the labial site, and #25 in the present report had vital pulp, no perforation repair, and a thin dentin defect, unlike the wedge-shaped defect, implying endodontic treatment, perforation repair, and the size (area and depth) of the root-dentin defect might have caused the worse prognosis of the labial bone regeneration in the previous case. Clinical research is necessary so that the classification of the size (area and depth) of a root-dentin defect, healthy vital pulp or non-vital pulp, and the presence or absence of perforation repair may be considered in the treatment strategy for periodontal destruction with a cemental tear in addition to the classification of class and stage (2).