Masahiro Iikubo1, Toyohiro Kagawa2, Junya Fujisawa3, Akira Kumasaka3, Takashi Nishioka3, Ikuho Kojima3, Maya Sakamoto3, Kaoru Kobayashi4, Kenji Yuasa2. 1. Division of Oral Diagnosis, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan. machapy@dent.tohoku.ac.jp. 2. Department of Diagnostic and General Care, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan. 3. Division of Oral Diagnosis, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan. 4. Department of Oral and Maxillofacial Radiology and Diagnosis, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan.
Abstract
OBJECTIVES: To ascertain the effects of exposure parameters (tube current and tube voltage) and the gutta-percha cone (GPC) size on root fracture-like artifacts obtained with cone-beam computed tomography (CBCT). METHODS: Fracture-like artifacts appearing on CBCT images of nine extracted human mandibular premolars filled with GPCs of size #50 or #80 were analyzed using six exposure factors: two tube voltages (80 kV and 110 kV); and three tube currents (4 mA, 7 mA, and 10 mA). On axial images, the gray value (GV) was recorded at three points: the mesiobuccal portion (MBP) as the sound dentin, the mesial portion (MP) as the artifact line, and the water area (WA). The rate of decrease in the GV (RDGV) of the artifact line was calculated using the formula: RDGV (%) = (GV of MBP - GV of MP) × 100/(GV of MBP - GV of WA). RESULTS: Comparison of the #80 group and the #50 group with equal tube voltages and tube currents shows that artifact lines in the #80 group were more obvious than those in the #50 group. The artifact lines with 80 kV were markedly more visible than those with 110 kV for each tube current and GPC size. Tube current changes did not affect the artifact line for any tube voltage or GPC size. CONCLUSIONS: For the reduction of artifacts, we recommend selection of higher tube voltages and lower tube currents when taking CBCT images of teeth with each GPC size.
OBJECTIVES: To ascertain the effects of exposure parameters (tube current and tube voltage) and the gutta-percha cone (GPC) size on root fracture-like artifacts obtained with cone-beam computed tomography (CBCT). METHODS: Fracture-like artifacts appearing on CBCT images of nine extracted human mandibular premolars filled with GPCs of size #50 or #80 were analyzed using six exposure factors: two tube voltages (80 kV and 110 kV); and three tube currents (4 mA, 7 mA, and 10 mA). On axial images, the gray value (GV) was recorded at three points: the mesiobuccal portion (MBP) as the sound dentin, the mesial portion (MP) as the artifact line, and the water area (WA). The rate of decrease in the GV (RDGV) of the artifact line was calculated using the formula: RDGV (%) = (GV of MBP - GV of MP) × 100/(GV of MBP - GV of WA). RESULTS: Comparison of the #80 group and the #50 group with equal tube voltages and tube currents shows that artifact lines in the #80 group were more obvious than those in the #50 group. The artifact lines with 80 kV were markedly more visible than those with 110 kV for each tube current and GPC size. Tube current changes did not affect the artifact line for any tube voltage or GPC size. CONCLUSIONS: For the reduction of artifacts, we recommend selection of higher tube voltages and lower tube currents when taking CBCT images of teeth with each GPC size.
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