Prediction of Fishman's skeletal maturity indicators using artificial intelligence.

The present study aimed to evaluate the performance of automated skeletal maturation assessment system for Fishman's skeletal maturity indicators (SMI) for the use in dental fields. Skeletal maturity is particularly important in orthodontics for the determination of treatment timing and method. SMI is widely used for this purpose, as it is less time-consuming and practical in clinical use compared to other methods. Thus, the existing automated skeletal age assessment system based on Greulich and Pyle and Tanner-Whitehouse3 methods was further developed to include SMI using artificial intelligence. This hybrid SMI-modified system consists of three major steps: (1) automated detection of region of interest; (2) automated evaluation of skeletal maturity of each region; and (3) SMI stage mapping. The primary validation was carried out using a dataset of 2593 hand-wrist radiographs, and the SMI mapping algorithm was adjusted accordingly. The performance of the final system was evaluated on a test dataset of 711 hand-wrist radiographs from a different institution. The system achieved a prediction accuracy of 0.772 and mean absolute error and root mean square error of 0.27 and 0.604, respectively, indicating a clinically reliable performance. Thus, it can be used to improve clinical efficiency and reproducibility of SMI prediction.

Skin irritation in children undergoing orthodontic facemask therapy.

Orthodontic facemasks are extraoral orthodontic appliances that influence maxillary and mandibular development in children with skeletal Class III malocclusion. While a facemask is most effective in patients before the growth spurt, skin irritation is common during the treatment. Therefore, this retrospective study aimed to investigate the prevalence and pattern of such skin changes and identify their possible associated risk factors. We included 177 patients with skeletal Class III malocclusion who underwent facemask therapy. Patient age and sex, orthodontic parameters expressing the severity of malocclusion, the presence of complaints in the temporomandibular joint (TMJ) areas, and the level of patient cooperation were evaluated. Additionally, the severity and onset time of skin reactions were further analyzed. The results indicated that 43.5% of patients developed skin changes typical of irritant contact dermatitis. Skin irritation was significantly associated with the presence of TMJ complaints and female sex. Furthermore, skin irritation was more common in younger patients. Clinicians should pay special attention to the skin areas that come into contact with the appliance during each follow-up visit to detect potential problems. Moreover, patients and their parents should be given adequate information about the possibility, prevention, and management of skin problems during facemask therapy.

Correlation and Correspondence between Skeletal Maturation Indicators in Hand-Wrist and Cervical Vertebra Analyses and Skeletal Maturity Score in Korean Adolescents.

This retrospective observational study aimed to examine the correlation and correspondence between skeletal maturation indicators (SMI), cervical vertebral maturation indicators (CVMI), and radius-ulna-short bones (RUS) skeletal maturity scores in Korean adolescents, and to determine whether easily obtainable SMI or CVMI can replace the RUS skeletal maturity score. A total of 1017 participants were included with both hand-wrist radiograph and lateral cephalogram acquired concurrently. From the lateral cephalogram, CVMI was determined; through the hand-wrist radiograph, SMI was categorized, and the RUS skeletal maturity score was evaluated as well. Associations were examined using the Mann-Whitney U test, Spearman's rank-order correlation analysis, and multiple correspondence analysis. There was no statistically significant difference in chronological age between males and females; however, the SMI, CVMI, and RUS skeletal maturity scores were significantly higher in females. The SMI, CVMI, and RUS skeletal maturity scores showed a statistically significant strong degree of both positive correlation and correspondence. However, a precisely corresponding RUS skeletal maturity score was difficult to obtain for a specific CVMI and SMI stage, implying the absence of a quantitative correlation. In conclusion, detailed evaluation should be conducted using the RUS skeletal maturity score, preferably in cases that require bone age determination or residual growth estimation.

Cone-beam computed tomography for the assessment of root-crown ratios of the maxillary and mandibular incisors in a Korean population.

OBJECTIVE: This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root-crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT). METHODS: We included 672 Korean patients (141 men and 531 women; mean age, 27.2 ± 7.7 years) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships. RESULTS: Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age. CONCLUSIONS: The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

The influence of age on lip-line cant in adults: a cross-sectional study.

OBJECTIVE: The aims of this study were to assess the direction and degree of lip-line cant in Korean adult orthodontic patients and to identify the effects of sex and age on changes in the cant severity. METHODS: In this cross-sectional retrospective study, lip-line cant was measured in the frontal photographs of 585 Korean patients (92 men and 493 women) aged 18-48 years. The outcome variables (direction and degree of lip-line cant) were assessed in terms of predictor variables (sex, age, sagittal skeletal relationship, and menton deviation angle). RESULTS: The direction of lip-line cant did not differ according to sex, age, or skeletal classification. Patients had 1.6° of lip-line cant on average before orthodontic treatment. Middle-aged adults displayed a significant trend toward a lower degree of lip-line cant compared to younger adults (p < 0.01). Multiple linear regression analysis showed that the degree of lip-line cant was weakly negatively correlated with age (p < 0.001). CONCLUSIONS: While the direction of lip-line cant did not differ according to the parameters explored here, the degree of cant was correlated with age in adults, independent of menton deviation. Specifically, middle-aged adults tended to display significantly lower degrees of lip-line cant than did younger adults.