Computed tomographic assessment of early changes of the mandible in bisphosphonate-treated patients.

OBJECTIVES: To compare the computed tomography (CT) features of mandibular cancellous and cortical bones between patients with bisphosphonate (BP) administration and those without and to assess the early changes of the mandible in BP-treated patients. STUDY DESIGN: Twenty-four BP-treated patients suffering from medication-related osteonecrosis of the jaw (MRONJ) were enrolled in this study. For comparison, 20 patients suffering from osteomyelitis and 20 patients without pathology in the jaw were also enrolled, all of whom did not receive BP treatment. The CT values of the cancellous and cortical bone and the cortical bone widths were measured. RESULTS: In the MRONJ and osteomyelitis groups, there were significant differences in the CT values of cancellous and cortical bones between the affected and unaffected areas. In patients with stage 0 MRONJ, a significant difference was noted in the cancellous bone CT values between these areas. The cancellous bone CT values at the affected and unaffected areas in the BP-treated group were significantly higher than in the control groups. In patients with stage 0 MRONJ, the cancellous bone CT values at the affected area were also significantly higher than in the healthy patients. The cortical bone widths in the unaffected areas in the BP-treated patients were significantly larger than in healthy patients. CONCLUSIONS: The cancellous bone CT values were higher in the BP-treated group, including in patients with stage 0 MRONJ, and CT may provide useful quantitative information.

Clinical and dental computed tomographic evaluation 1 year after coronectomy.

PURPOSE: Coronectomy is performed when contact between the mandibular third molar apex and the inferior alveolar nerve is suspected. The efficacy of coronectomy compared with conventional tooth extraction has been recognized in recent years. However, few studies have reported the postoperative prognosis of roots remaining in the bone or surrounding tissue. Therefore, a clinical evaluation was performed with dental computed tomographic imaging of the coronectomy sites 1 year after the procedure. PATIENTS AND METHODS: This study investigated 101 patients (116 teeth) who underwent a coronectomy from March 2006 through December 2009. They were recalled 1 year later for a clinical evaluation and dental computed tomographic imaging of the coronectomy sites. The clinical evaluation was based on palpation and macroscopic findings. RESULTS: In 99.2% (115 teeth) of the studied cases, the soft tissue distal to the mandibular second molar was healthy and the retained roots were covered by bone. In 1 case (0.8%), an eruption of roots into the oral cavity was observed; however, no inflammation was observed in the nearby soft tissue. In all 116 teeth, no transmission images indicative of periapical lesions, which usually result from necrosis of the pulp, were observed in the apical area of the retained roots. CONCLUSIONS: The absence of transmission images indicative of periapical lesions and the presence of bone covering more than 99.2% (115 teeth) of the retained roots showed a safe postoperative course at the 1-year follow-up after coronectomy.

Clinical evaluations of coronectomy (intentional partial odontectomy) for mandibular third molars using dental computed tomography: a case-control study.

PURPOSE: Studies have suggested that coronectomy reduces the risk of inferior alveolar nerve injury (IANI) when a close relationship with the inferior alveolar canal is indicated on panoramic imaging. However, the relationship between the inferior alveolar canal and the root are unclear on panoramic imaging. Our aim was to compare coronectomy with traditional extraction for the treatment of mandibular third molars that had clear high IANI risks as evaluated by dental computed tomography. PATIENTS AND METHODS: We designed a case-control study of subjects with high-risk signs of IANI on panoramic images evaluated by dental computed tomography before enrollment. The 220 patients enrolled were assigned to extraction (control group, n = 118) or coronectomy (case group, n = 102). RESULTS: The mean follow-up time was 13 months in the extraction group and 13.5 months in the coronectomy group. Six IANIs (5%) were found in the extraction group. In the coronectomy group, 1 patient (1%) had symptoms of neurapraxia, which disappeared within 1 month. Four remaining roots had signs of postoperative infection, and the patients underwent extraction of the root. No nerve damage resulted in these patients after repeat extraction. CONCLUSIONS: Coronectomy might reduce the risk of nerve injury for patients at true high risk of IANI as evaluated by dental computed tomography. A long-term postoperative review is needed to assess the incidence of root migration and the root extraction and infection rates after coronectomy.

MRI features of mandibular osteomyelitis: practical criteria based on an association with conventional radiography features and clinical classification.

OBJECTIVES: The aims of this study were (1) to assess the diagnostic power of magnetic resonance imaging (MRI) for mandibular osteomyelitis through comparison with conventional techniques and (2) to establish practical MRI diagnostic criteria in relation to treatment and clinical outcome. STUDY DESIGN: In 55 subjects, clinically suspected as mandibular osteomyelitis, signal intensities (SI) were evaluated on T1-weighted/short T1 inversion recovery (STIR) images. RESULTS: Forty-seven subjects were definitively diagnosed as having osteomyelitis by pathology studies or clinical course. For the acute or subacute stage, positively associated appearances were low SI on T1-weighted image and extensive high or focal high SI on the STIR image. For chronic stage, appearances of low SI on both T1-weighted and STIR images should be added to those for the acute or subacute stage. These findings support the at-present accepted imaging diagnostic criteria based on bony changes for detection of osteomyelitis. CONCLUSION: This study confirms that T1-weighted/STIR images are useful for the detection of mandibular osteomyelitis.