Preliminary study: evaluating the reliability of CBCT images for tongue space measurements in the field of orthodontics.

INTRODUCTION: Accurately measuring tongue space is challenging, but this information can be useful to many dental specialties. This study was intended to estimate the reliability of using cone-beam computed tomography (CBCT) to measure tongue space, which includes tongue volume and the oral cavity air capacity. METHODS: For this preliminary study, CBCT images from ten participants (five females and five males, mean age of 29.8 ± 3.3 years) were available for evaluation. Each participant was radiographed two times (T0 and T1). The average time between T0 and T1 was 15.8 ± 3.7 days. CBCT scans were standardized to reduce variability. Three-dimensional landmarks were established to identify tongue space and 3D image analysis software (SimPlant® 17 Pro; Materialise Dental, Leuven, Belgium) was used to measure the volume circumscribed by the landmarks. Two investigators independently calculated airway, tongue dimensions, and total tongue space for CBCT image T0 twice (day 1 and day 14), and T1 once. Intraclass correlation coefficients (ICCs) were used to estimate intra-rater and inter-rater reliability. Bland-Altman charts were constructed to demonstrate agreement within and between raters. RESULTS: The intra-rater and inter-rater ICCs of the CBCT measurements at T0 were excellent (> 0.90). Measurements for T0 vs. T1 show good (0.75-0.90) intra-rater and excellent (> 0.90) inter-rater reliability. Bland-Altman charts show that 90-95% of the total measurements fall within the 95% limits of agreement for both intra- and inter-rater pairs CONCLUSIONS: The results of this preliminary study suggest that the landmarks chosen to measure the overall tongue space are reproducible and can be measured clearly using CBCT.

The study of tooth angulation and inclination for bracket design of Deutromalay race: A comparison study to white race.

BACKGROUND: The Indonesian population consist of Deutromalay and Protomalay races, with the Deutromalay race being most of the population. In 1972, Lawrence F. Andrews introduced the "six keys of normal occlusion," which was based on a white sample. This study aimed to identify standard tooth angulation and inclination in the Deutromalay race, which might help in future development of bracket prescription specific to the population. METHODS: This cross-sectional study was conducted on a representative sample of 190 subjects (112 male and 78 female subjects) aged 14 to 22 years from the Deutromalay population. Data collection was performed by two investigators following the methodology prescribed by Andrews for measuring tooth crown angulations and inclinations. Inter-rater reliability was measured with kappa statistics. Data were analyzed using SPSS software, version 25. Independent-samples t-tests were used for significance testing. The alpha level for statistical significance was set at 0.05, two-tailed. RESULTS: The kappa statistic came out to be 0.80, which showed substantial agreement. The results of the t-test for tooth angulation and inclination found significant differences between male and female subjects for some teeth within the Deutromalay sample. In addition, significant differences were found for most teeth between the Deutromalay and white samples. CONCLUSIONS: Significant differences in crown angulation and inclination values exist for most teeth in the Deutromalay sample studied compared with the white norms reported by Andrews. This points to the possible need to develop a new preadjusted bracket prescription specific for the Indonesian (Deutromalay) population.