The reliability of analytical reference lines for determining esthetically pleasing lip position: An assessment of consistency, sensitivity, and specificity.

INTRODUCTION: This study aimed to identify a simple yet reliable soft-tissue parameter for the clinical determination of esthetic lip position by investigating the most consistent reference lines and assessing their sensitivity and specificity. METHODS: A total of 5745 records from Chinese patients aged >18 years were screened. In part I of the study, lateral view photographs of 96 subjects (33 males, 63 females) with esthetic facial profiles were selected. The profile esthetics of each photograph was first scored by 52 dental students, followed by 97 laypeople on a 5-point attractiveness scale. For the top 25% of photographs with the highest score for each sex (8 males, 16 females), the consistency of 6 commonly used reference lines were assessed to determine the esthetic lip position. In part II of the study, lip positions relative to Steiner's (S) and Ricketts' (E) lines in the profile photographs of 86 patients (43 males, 43 females) deemed to have an esthetically unpleasing profile were compared with those in 86 Chinese movie star idols (43 males, 43 females). RESULTS: In part I of the study, the S, E, and Burstone's (B) lines exhibited the lowest standard deviations for the upper and lower lips. B line was excluded from further analysis because of its higher mean absolute values, and S and E lines were used for the subjective assessment in part II of the study. In part II, the S line showed a sensitivity of 86.0% and 86.0% and a specificity of 81.4% and 83.7% for males and females, respectively. In contrast, the E line presented a sensitivity of 88.4% and 93.0% and a specificity of 79.1% and 74.4% for males and females, respectively. CONCLUSIONS: S, E, and B lines were the most consistent soft-tissue parameters among both sexes; however, because of the smaller absolute values, the S line would be more convenient among the 3 for a quick clinical assessment of lip position. Moreover, the performance of both S and E lines was similar among both sexes, which supports using these lines in assessing the esthetic lip position.

Orthodontic Treatment Need and the Psychosocial Impact of Malocclusion in 12-Year-Old Hong Kong Children.

OBJECTIVES: To determine the prevalence of orthodontic treatment need in 12-year-old children in Hong Kong and its relationship with the psychosocial impact of malocclusion and to assess their associations with sociodemographic factors. MATERIALS AND METHODS: A random sample of 687 12-year-old children was recruited from 45 secondary schools in Hong Kong. Orthodontic treatment need was assessed on study models by five indices: the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC), the Aesthetic Component of the IOTN (IOTN-AC), the Dental Aesthetic Index (DAI), the Index of Complexity Outcome and Need (ICON), and the Peer Assessment Rating (PAR). The psychosocial impact of malocclusion on participants and sociodemographic factors were obtained from a questionnaire. Logistic regression was used to examine the correlations between treatment need and the psychosocial impact of malocclusion as well as their associations with sociodemographic factors. RESULTS: The final number of participants was 667 (339 boys and 328 girls, participation rate 667/687 = 97.1%). The prevalence of orthodontic treatment need varied depending on the indices used (10.9-47.8%), but significant correlations were found among the five indices (p < 0.01). The uptake of treatment among the cohort was 2.3%. Boys had higher IOTN-DHC (p < 0.05), DAI (p < 0.05), and PAR (p = 0.05) scores than girls. IOTN-AC was significantly associated with the psychosocial impact of malocclusion (p < 0.05). Parents' level of education and household income were not significantly associated with either treatment need or the psychosocial impact of malocclusion (p > 0.05). CONCLUSION: The need for orthodontic treatment in 12-year-old children in Hong Kong remained high, and the uptake of treatment was low. Boys had a higher normative treatment need than girls. Among the five indices, IOTN-AC appears to be the best indicator of the psychosocial impact of malocclusion.

The within-host population dynamics of Mycobacterium tuberculosis vary with treatment efficacy.

BACKGROUND: Combination therapy is one of the most effective tools for limiting the emergence of drug resistance in pathogens. Despite the widespread adoption of combination therapy across diseases, drug resistance rates continue to rise, leading to failing treatment regimens. The mechanisms underlying treatment failure are well studied, but the processes governing successful combination therapy are poorly understood. We address this question by studying the population dynamics of Mycobacterium tuberculosis within tuberculosis patients undergoing treatment with different combinations of antibiotics. RESULTS: By combining very deep whole genome sequencing (~1000-fold genome-wide coverage) with sequential sputum sampling, we were able to detect transient genetic diversity driven by the apparently continuous turnover of minor alleles, which could serve as the source of drug-resistant bacteria. However, we report that treatment efficacy has a clear impact on the population dynamics: sufficient drug pressure bears a clear signature of purifying selection leading to apparent genetic stability. In contrast, M. tuberculosis populations subject to less drug pressure show markedly different dynamics, including cases of acquisition of additional drug resistance. CONCLUSIONS: Our findings show that for a pathogen like M. tuberculosis, which is well adapted to the human host, purifying selection constrains the evolutionary trajectory to resistance in effectively treated individuals. Nonetheless, we also report a continuous turnover of minor variants, which could give rise to the emergence of drug resistance in cases of drug pressure weakening. Monitoring bacterial population dynamics could therefore provide an informative metric for assessing the efficacy of novel drug combinations.