Case report
A 75-year-old woman with osteoporosis visited Nippon Kokan Fukuyama Hospital with a chief complaint of a gingival abscess and swelling around #9. Her gingiva in all areas of the mouth except #9 and #25 was healthy (Figure 1A) and she had good oral hygiene (plaque control record: 13.8%). Her #9 was found to have received trauma two years earlier and to have a vertical root fracture. Therefore, #9 was extracted with her informed consent. In contrast, the patient had no subjective symptoms related to #25. A sinus tract was observed on the labial side of the gingiva around #25 (Figure 1A); #25 responded positively to thermal and electric pulp vital tests by PULPER® (GC, Tokyo, Japan) and Digitest® (Parkell, Farmingdale, NY, USA). Pocket probing depth (PPD) on #25 was 3 mm in all areas except the labial center, whose PPD was 9 mm. Probing of the labial center resulted in bleeding. Clinical attachment loss at #25 of the labial center was 16 mm; #25 was inclined labially and showed tooth attrition (Figure 1B). A gutta-percha point (size 40/02; GC Dental Industrial Corp., Tokyo, Japan) was used to trace the periodontal pocket of the labial center (Figure 1B). Radiography showed that the tip of the gutta-percha point inserted into the sinus tract reached the mesial site at one-fourth of the root length from the root apex of #25 (Figure 1C). Radiolucent areas were not observed around the tip of the inserted gutta-percha point (Figure 1C). Dental radiographs in the orthoradial projection and the eccentric projection of #25 showed no radiopaque fragments at the root (Figure 1D). The patient’s oral hygiene was good, and her gingiva and bone levels in all areas of the mouth except #25 were healthy, suggesting that #25 should be classified as a periodontal abscess in a non-periodontitis patient (14, 15).
Cone-beam computed tomography (CBCT) images (3DX Multi-Image Micro CT FPD8; J Morita, Tokyo, Japan) of #25 showed an extensive bone defect on the labial aspect and narrow-range defects on the mesial and distal aspects at the buccal side (Figure 2A and B). Three-dimensional reconstruction of CBCT images showed narrow shallow vertical bone defects from the existing marginal bone in the three sites (Figure 2C). Radiopaque thin fragments, which were completely and incompletely detached from the root surface, were observed at the distal-labial and mesial-labial aspects of the root (Figure 2A and B). This was diagnosed as a case of cemental tear accompanied by severe periodontitis. According to the new three-dimensional classification of cemental tears (2), this case was classified as Class 3 (clinically inaccessible, infrabony and/or dehiscence, no apical involvement)/Stage C (cemental tear and the associated bony defect involves 3 surfaces of the root). The clinical symptoms and the results of the examinations suggested that whileendodontic treatment was not necessary, periodontal treatment (surgical removal of cemental fragments and granulomatous tissue, biopsy of removed tissues, and periodontal regenerative therapy with rhFGF-2) was. Informed consent was obtained from the patient after explanation of the risks, benefits, and costs of the proposed treatments.
Occlusal adjustment was conducted at the anterior tooth to improve occlusal function after extraction of #9. After scaling and root planing had been carried out, the periodontal pocket (PPD of the labial center: 9 mm) remained, although the swelling, abscess, and sinus tract had disappeared (Figure 3A). Under disinfection with povidone iodine and local anesthetic administration with Xylocaine®(DENTSPLY-Sankin Co., Tochigi, Japan) in the right mandibular region, a full-thickness mucoperiosteal flap with a single-flap approach to the labial access was raised (Figure 3B). After granulomatous tissue was partially removed (Figure 3C), cemental fragments on the root were stained with methylene blue dye (MORIMURA DENTAL Co., Tokyo, Japan) (Figure 3D). After the removal of cemental fragments and the remaining granulomatous tissue with hand curettes under the dental operating microscope, the range of the bone defect was found on the proximal and labial aspects (Figure 3E and F). Subsequently, root planing was conducted. A thin dentin defect that did not extend to the wedge-shaped defect occurred on the labial-site root. For this, rhFGF-2 (Kaken Pharmaceutical Co., Tokyo, Japan) was applied into the bone defect (Figure 3G). The flap was then repositioned without tension and sutured with 7-0 nylon (Mani, Tochigi, Japan) (Figure 3H). During surgery, the cemental fragments (Figure 3I) and granulomatous tissues (Figure 3J) were collected for biopsy.
Histopathological examination of the removed cemental fragment with hematoxylin and eosin (HE) staining showed the acellular cementum (Figure 4A and B). A thin layer of fibrous connective tissue representing the periodontal ligament was attached to the cemental fragment (Figure 4B). Gram-positive bacteria (Figure 4C) and periodic acid-Schiff (PAS)-positive bacteria (Figure 4D) were observed on the cemental fragment. Small, scattered cemental fragments existed within the removed granulomatous tissue (Figure 5A and B). Gram-positive bacteria (Figure 5C) and PAS-positive bacteria (Figure 5D) were observed on the small, scattered cemental tears within the granulomatous tissue.
Two years after the surgery, no abnormal findings were seen radiographically (Figure 6A), and clinically healthy soft tissues were observed without severe gingival recession (Figure 6B). PPD of all sites was 2 mm. #25 had no bleeding on probing and no tooth mobility. The clinical attachment level of the labial center was improved from 16 mm to 9 mm (attachment gain: 7 mm). CBCT 2 years after the surgery showed reconstruction of the labial bone wall (Figure 7A, B and C) and proximal bone walls (Figure 7B). In particular, the regenerated labial bone had a similar height to the lingual bone (Figure 7A).