相澤 貴子

Objective The usefulness of computed tomography (CT) for measuring bone defect volume in the alveolar cleft has attracted considerable attention in recent years. Moreover, 320-row area detector CT (320-ADCT) is currently widely utilized. This technology helps to acquire smooth three-dimensional images, with a reduced exposure dose and improved image resolution, similar to those of dental cone-beam CT (CBCT). We compared the exposure dose of 320-ADCT with that of dental CBCT, and analyzed the reliability of a volumetric method for measuring bone defects in the alveolar cleft using 320-ADCT, both experimentally and clinically. Methods We performed thermoluminescent dosimeter measurements using an anthropomorphic RANDO phantom. Additionally, we evaluated the reproducibility of the volumetric measurement method for the bone defective volume using CT images of simulated bone defects in pigs. In addition, we evaluated the inter-rater reliability of the volumetrically measured values of bone defects in 20 patients with a unilateral cleft. Results The exposure doses of 320-row area detector CT and CBCT were similar. The errors of volumetric values between calculated and actual bone defects created in pigs were up to 7.6%. Inter-rater reliability of the calculated volumes of bone defect was evaluated as high, according to Bland–Altman analysis. Conclusions CT examination with a low exposure dose and precise analysis is feasible without the use of highly specialized dental CBCT.

Objective: Our objective is to determine appropriate specifications for smaller tongue blade for Japanese pediatric patients with cleft palate (CP) and mandibular micrognathia. Patients: We investigated 59 patients who underwent palatoplasty. Patients were divided into two groups: the micrognathia (MG) group consisted of 11 patients and the normognathia (NG) group consisted of 48 patients. Interventions: The following five items were investigated retrospectively: (1) gender, (2) cleft type, (3) age at the time of surgery, (4) weight at the time of surgery, and (5) distance from the tongue blade base to the posterior pharyngeal wall (Dis). Results: There was a significant difference (P < .01) in age at the time of surgery and in Dis between groups, but not in weight. The minimum values were 55 mm for the MG group. As for correlations between age and weight at the time of surgery, the P values for the MG and NG groups were .993 and .052, respectively. As for correlations between weight at the time of surgery and Dis, the P values for the MG and NG groups were .987 and .099, respectively. Conclusions: It was difficult to predict Dis on the basis of the patient's age and weight measured preoperatively. The minimum Dis was 55 mm, equal to the length from the base to the tip of the Dingman Mouth Gag tongue blade currently in use, suggesting that a tongue blade of approximately 50 mm in length, shorter than the current minimum specifications, may be appropriate.