Facial growth and development trajectories based on three-dimensional images: geometric morphometrics with a deformation perspective

Developmental changes of facial shape are commonly investigated through geometric morphometrics. A limitation with this approach is the inability to investigate patterns of morphological changes at local scale. This could be addressed through quantifying the deformation required to deform one shape to another. This study aimed to investigate changes in mean, rate and variance of facial shape at local scale using geometric morphometrics through deformation perspective. A total of 2112 Europeans 3 to 40 years old from the three-dimensional Facial Norms project were included. Shape and rate trajectories from partial least-squares regressions revealed that the developmentally protrusive nasal bridge was due to local expansion in surrounding tissues as opposed to shape changes in nasal bridge per se. Local expansion of the supraorbital region, in particular the medial part in males, resulted in the sloping forehead and deep-situated eyes with development. Facial shape variation increased nonlinearly with age (p < 0.05), with features having larger rate of change becoming more developmentally diversified. In summary, our deformation perspective facilitates unravelling morphogenetic processes underlying shape changes. Our extended analytical scope inspires novel measures worthy of consideration while establishing facial growth charts. The analytical framework in this study is broadly applicable for analysis of shape changes in general.

Burden, Trends, and Inequality of Dental Caries in the U.S., 1990-2019

INTRODUCTION

Over the past 2 decades in the U.S., the reduced burden and narrowed inequality in oral health among children are in stark contrast with the high burden and widening inequality in adult oral health. This study aimed to explore the burden, trends, and inequalities of untreated caries in permanent teeth in the U.S. during 1990-2019.

METHODS

Data on burden of untreated caries in permanent teeth were extracted from the Global Burden of Disease Study 2019. A set of advanced analytical methods were applied to provide an in-depth characterization of the epidemiologic profile of dental caries in the U.S. Analyses were conducted during April 2022-October 2022.

RESULTS

In 2019, age-standardized incidence and prevalence of untreated caries in permanent teeth were respectively 39,111.7 (95% uncertainty interval=35,073.0-42,964.9) and 21,722.5 (95% uncertainty interval=18,748.7-25,090.3) per 100,000 person-years. Population growth was the primary driver of the increased caries cases, which contributed 31.3% and 31.0% of the increase in the number of incident and prevalent caries cases, respectively, during 1990-2019. The highest caries burden was noted in Arizona, West Virginia, Michigan, and Pennsylvania. The slope index of inequality remained stable (p=0.076), whereas the relative index of inequality increased significantly (average annual percent change=0.04, p<0.001) in the U.S. The burden of untreated caries in permanent teeth remained significant with a widening cross-state inequality during 1990-2019.

CONCLUSIONS

The oral healthcare system in the U.S. needs to prioritize health promotion and prevention with a focus on expanding access, affordability, and equity.

Global Burden and Inequality of Dental Caries, 1990 to 2019

Previous studies on the global burden of caries primarily focused on simple descriptive statistics. We aimed to characterize the burden, trends, and inequalities of untreated caries of permanent and deciduous teeth from 1990 to 2019 at the global, regional, and national levels through an array of analytic approaches. Estimates of caries burden were extracted from the Global Burden of Disease Study 2019. Decomposition analysis was performed to examine the contribution of demographic and epidemiologic factors to the evolving number of prevalent caries cases. In portfolio analysis, the caries epidemiologic profile of each country was categorized by terciles of age-standardized prevalence in 2019 and average annual percentage change from 1990 to 2019. Sociodemographic attribution analysis was performed to reveal the scale of inequality in burden of caries. Age-standardized prevalence of caries in permanent and deciduous teeth decreased 3.6% (95% uncertainty interval, 2.6% to 4.5%) and 3.0% (1.3% to 4.9%), respectively. Population growth was the key driver of the changes in the number of caries cases, especially in sub-Saharan Africa (percentage contribution: 126.6%, permanent teeth; 103.0%, deciduous teeth). Caries prevalence in the permanent dentition was lower in more developed countries, whereas a reverse trend was noted in the deciduous dentition, except for the highest sociodemographic quintile where caries prevalence was the lowest. Globally, 64.6 million (95% CI, 64.4 to 64.9 million) and 62.9 million (62.8 to 63.1 million) prevalent cases of caries in permanent and deciduous teeth were attributable to sociodemographic inequality in 2019. This amounted to 3.2% (3.2% to 3.2%) and 12.1% (12.1% to 12.1%) of the global number of prevalent cases of caries in permanent and deciduous teeth. Burden of dental caries remains a global public health challenge. A systemwide reform of the global oral health care system is needed to tackle the causes of the burden and inequality of dental caries.