Global, regional, and national burden of severe periodontitis, 1990-2019: An analysis of the Global Burden of Disease Study 2019.

AIM: Up-to-date epidemiological studies on the global burden of severe periodontitis is scarce. This study aimed to present the latest estimates for prevalence of severe periodontitis from 1990 to 2019, by region, age, and level of socio-demographic development. MATERIALS AND METHODS: Estimates from the Global Burden of Disease study 2019 were used to investigate burden and trends of prevalence of severe periodontitis and its association with socio-demographic development at global, regional, and national level. Decomposition analysis was performed to explore the contribution of demographic and epidemiological factors to the evolving burden of severe periodontitis. RESULTS: In 2019, there were 1.1 billion (95% uncertainty interval: 0.8-1.4 billion) prevalent cases of severe periodontitis globally. From 1990 to 2019, age-standardized prevalence rate of severe periodontitis increased by 8.44% (6.62%-10.59%) worldwide. Prevalence of severe periodontitis is higher among less developed countries/regions. Global population growth accounted for 67.9% of the increase in the number of prevalent cases of severe periodontitis from 1990 to 2019. CONCLUSIONS: The global burden of severe periodontitis has been substantial and increasing over the past three decades. Upstream policy changes are urgently needed to address the global public health challenge of severe periodontitis.

Soft tissue facial changes among adult females during alignment stage of orthodontic treatment: a 3D geometric morphometric study.

BACKGROUND: To investigate changes in facial morphology during the first six months of orthodontic treatment among adult females receiving orthodontic treatment. METHODS: 43 adult females receiving orthodontic treatment were randomly recruited. 3D facial images were taken at baseline (T0), three months (T1), and six months (T2) after treatment initiation. Spatially dense facial landmarks were digitized to allow for sufficient details in characterization of facial features. 3D geometric morphometrics and multivariate statistics were used to investigate changes in mean and variance of facial shape and facial form associated with treatment. RESULTS: We observed statistically significant changes in facial shape across the three treatment stages (p = 0.0022). Pairwise comparisons suggested significant changes from T0 to T1 (p = 0.0045) and from T0 to T2 (p = 0.0072). Heatmap visualization indicated that the buccal and temporal region were invaginated while the labial region became protruded with treatment. The magnitude of shape change was 0.009, 0.004, and 0.010 from T0 to T1, T1 to T2, and T0 to T2, respectively, in unit of Procrustes distance. The average magnitude of change per-landmark was 1.32 mm, 0.21 mm, and 1.34 mm, respectively. Changes in mean facial form were not statistically significant (p = 0.1143). No changes in variance of facial shape were observed across treatment stages (p > 0.05). CONCLUSION: Rate of facial changes was twice as fast during the first three months as that during fourth to sixth month. Buccal and temporal region became invaginated while labial region became protruded with treatment.

Oral health status of children and adolescents with intellectual disabilities: a systematic review and meta-analysis.

AIM: To compare the oral health status of children and adolescents affected by intellectual disabilities with their unaffected counterparts. METHOD: Citations published in English were searched from electronic databases (PubMed, Embase, Web of Science, and Scopus) from their start dates to March 2017. The whole process was conducted following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. The PICO (population, intervention/interest, comparator, outcome) principle was used to formulate the topic. Studies were synthesized through qualitative summary or, whenever possible, meta-analysis. RESULTS: The initial search yielded 2393 records. Thirty-nine studies from 22 countries were identified for qualitative analysis; 26 studies were eligible for meta-analysis. Participants with intellectual disabilities had higher levels of dental plaque, worse gingival status, fewer decayed and filled permanent teeth, and similar caries experience between males and females. These findings were supported by both qualitative and quantitative analysis. Various patterns of caries experiences were indicated by qualitative analysis, but it was not substantiated by meta-analysis. INTERPRETATION: There is increasing worldwide interest in oral health status of children with intellectual disabilities. Differences in dental plaque deposition, gingival inflammation, and the number of decayed and filled permanent teeth were investigated between children and adolescents with and without intellectual disabilities. Evidence remains elusive about the pattern of caries experience among those children.

Longitudinal Photogrammetric Analysis of Soft Tissue Facial Changes: A Systematic Review of the Literature and a Summary of Recommendations.

Human faces are under a constant state of change throughout the entirety of one's lifetime. Photogrammetry has been advocated for use in large epidemiological studies investigating facial characteristics. This study aimed to review existing longitudinal photogrammetric studies in terms of the measurements selected and the observed facial changes overtime. A comprehensive literature search was performed in 4 databases, PubMed, ISI Web of Science, EMBASE, and Scopus, which was supplemented by hand search. No limitations were set as to the language, dates, or status of publication. The records were assessed for the eligibility and rated for the risk of bias by 2 independent reviewers. Data regarding study characteristics, measurements selected and the outcomes reported, were extracted for analysis. An initial search identified 5127 studies. After 2 rounds of study screening, 6 eligible studies informed this review. The risk of bias of the studies ranged from 41.7% to 80.8%. Only 1 study performed sample size calculation, and only 17% of the studies had a sample size of over 30 subjects. Confidence interval was reported by none of the studies. The facial features assessed varied among the studies, and some studies focused on only specific regions of the face. Photogrammetry has been used by a limited number of studies in the analysis of longitudinal soft tissue facial changes. Moreover, these studies are heterogeneous with respect to their levels of risk of bias and the facial features assessed. Recommendations are provided to improve the qualities of future photogrammetric studies.

Survival Analysis and Risk Factors of Pulpectomy among Children with Severe Early Childhood Caries Treated under General Anesthesia: A Retrospective Study.

OBJECTIVES: This study aims to retrospectively evaluate the survival rate of pulpectomy performed under dental general anesthesia (DGA) through long-term follow-up and to explore the risk factors associated with treatment failure. METHODS: The medical records of the children who were diagnosed with S-ECC and received pulpectomy treatment under general anesthesia (GA) from 1 August 2014 to 1 December 2019, in the Stomatological Hospital of Xi'an Jiaotong University, were collected. Two dentistry postgraduates extracted the necessary information and filled in a predesigned excel form. Survival analysis was performed using the Kaplan-Meier method. The shared frailty model was used to explore possible factors affecting the success rate of pulpectomy in primary teeth. RESULTS: A total of 381 children (mean age 3.49 ± 0.90) with S-ECC and 1220 teeth were included in the study, including 590 primary anterior teeth and 630 primary molars. The overall 35-month survival rate was 38.5%, which was 52.9% for anterior teeth and 31.1% for molars. The overall median survival time was 31 months, in which anterior teeth were 35 months and molars were 26 months. The older the children were, the greater the risk of treatment failure (HR 1.56, 95% CI 1.09, 2.24). The risk of pulpectomy failure of primary molars was 1.9 times that of primary anterior teeth (95% CI 1.36, 2.65) and the teeth with abnormal radiological findings before treatment was 1.41 times higher than that of teeth without imaging abnormalities (95% CI 1.74, 3.36). CONCLUSION: The survival rate of primary tooth pulpectomy is acceptable but decreased gradually with time. The failure rate of pulpectomy in primary molars is higher than that of primary anterior teeth. When the primary caries has extended to the pulp and resulted in a nonvital lesion, pulpectomy could be an option for maximum retention of the primary tooth.

Efficacy of COVID-19 Treatments: A Bayesian Network Meta-Analysis of Randomized Controlled Trials.

Background: We provided a comprehensive evaluation of efficacy of available treatments for coronavirus disease 2019 (COVID-19). Methods: We searched for candidate COVID-19 studies in WHO COVID-19 Global Research Database up to August 19, 2021. Randomized controlled trials for suspected or confirmed COVID-19 patients published on peer-reviewed journals were included, regardless of demographic characteristics. Outcome measures included mortality, mechanical ventilation, hospital discharge and viral clearance. Bayesian network meta-analysis with fixed effects was conducted to estimate the effect sizes using posterior means and 95% equal-tailed credible intervals (CrIs). Odds ratio (OR) was used as the summary measure for treatment effect. Bayesian hierarchical models were used to estimate effect sizes of treatments grouped by the treatment classifications. Results: We identified 222 eligible studies with a total of 102,950 patients. Compared with the standard of care, imatinib, intravenous immunoglobulin and tocilizumab led to lower risk of death; baricitinib plus remdesivir, colchicine, dexamethasone, recombinant human granulocyte colony stimulating factor and tocilizumab indicated lower occurrence of mechanical ventilation; tofacitinib, sarilumab, remdesivir, tocilizumab and baricitinib plus remdesivir increased the hospital discharge rate; convalescent plasma, ivermectin, ivermectin plus doxycycline, hydroxychloroquine, nitazoxanide and proxalutamide resulted in better viral clearance. From the treatment class level, we found that the use of antineoplastic agents was associated with fewer mortality cases, immunostimulants could reduce the risk of mechanical ventilation and immunosuppressants led to higher discharge rates. Conclusions: This network meta-analysis identified superiority of several COVID-19 treatments over the standard of care in terms of mortality, mechanical ventilation, hospital discharge and viral clearance. Tocilizumab showed its superiority compared with SOC on preventing severe outcomes such as death and mechanical ventilation as well as increasing the discharge rate, which might be an appropriate treatment for patients with severe or mild/moderate illness. We also found the clinical efficacy of antineoplastic agents, immunostimulants and immunosuppressants with respect to the endpoints of mortality, mechanical ventilation and discharge, which provides valuable information for the discovery of potential COVID-19 treatments.

Differential Psychological Factors Associated With Unnecessary Dental Avoidance and Attendance Behavior During the Early COVID-19 Epidemic.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 is challenging the dental community to an unprecedented degree. Knowledge of the increased risk of infection in dental settings has been disseminated to the public and guidelines have been formulated to assist dental attendance decision-making. However, dental attendance behaviors incompatible with treatment need is not uncommon in clinical settings. Important gaps remain in the knowledge about how psychological factors are affecting dental attendance behaviors during the COVID-19 epidemic. In this cross-sectional study, a questionnaire survey was performed during February and March 2020. A total of 342 and 294 dental patients who attended and avoided dental visits, respectively, were included. The participants were classified into four groups based on dental attendance behavior and emergent/urgent dental treatment need. Bivariate analysis was performed to investigate factors associated with dental attendance. Multivariable logistic regression based on principal component scores was performed to identify major psychological constructs associated with unnecessary dental avoidance and attendance. Among all the factors explored, inability to wear masks during dental treatment (P < 0.001; effect size: 0.32) was most closely associated with the overall pattern of dental attendance among participants. Multivariable regression suggested that unnecessary dental avoidance was associated with perceived risk of infection in general and in dental settings (odds ratio [95% CI]: 0.62 [0.53, 0.72]; p < 0.001), perceived impact of COVID-19 and dental problems on general health (0.79 [0.65, 0.97]; 0.021), and personal traits such as trust and anxiety (0.77 [0.61, 0.98]; 0.038). Unnecessary dental attendance was associated with optimism toward the epidemic (1.68 [1.42, 2.01]; <0.001) and trust (1.39 [1.13, 1.74]; 0.002). Multidisciplinary efforts involving dental and medical professionals as well as psychologists are warranted to promote more widespread adoption, among the general public, of dental attendance behaviors compatible with dental treatment need during the COVID-19 epidemic.

The global, regional, and national burden of cancer among adolescents and young adults in 204 countries and territories, 1990-2019: a population-based study.

BACKGROUND: Accurate appraisal of burden of adolescents and young adults (AYAs) cancers is crucial to informing resource allocation and policy making. We report on the latest estimates of burden of AYA cancers in 204 countries and territories between 1990 and 2019 in association with socio-demographic index (SDI). PATIENTS AND METHODS: Estimates from the Global Burden of Disease study 2019 were used to analyse incidence, mortality, and disability-adjusted life years (DALYs) due to AYA cancers at global, regional, and national levels by sex. Association between AYA cancer burden and SDI were investigated. Burdens of AYA cancers were contextualized in comparison with childhood and older adult cancers. All estimates are reported as counts and age-standardized rates per 100,000 person-years. RESULTS: In 2019, there were 1.2 million incident cases, 0.4 million deaths, and 23.5 million DALYs due to AYA cancers globally. The highest age-standardized incidence rate occurred in Western Europe (75.3 [Females] and 67.4 [Males] per 100,000 person-years). Age-standardized death (23.2 [Females] and 13.9 [Males] per 100,000 person-years) and DALY (1328.3 [Females] and 1059.2 [Males] per 100,000 person-years) rates were highest in Oceania. Increasing SDI was associated with a higher age-standardized incidence rate. An inverted U-shaped association was identified between SDI and death and DALY rates. AYA cancers collectively is the second leading cause of non-communicable diseases-related deaths globally in 2019. DALYs of AYA cancers ranked the second globally and the first in low and low-middle SDI locations when compared with that of childhood and older adult cancers. CONCLUSION: The global burden of AYA cancers is substantial and disproportionally affect populations in limited-resource settings. Capacity building for AYA cancers is essential in promoting equity and population health worldwide.

Trends in the Burden of Untreated Caries of Permanent Teeth in China, 1993-2017: An Age-Period-Cohort Modeling Study.

INTRODUCTION: This study aims to identify the trends in incidence and prevalence of untreated caries in permanent teeth in China during 1993-2017. METHODS: Data representing >31 billion person-years of observation from the Global Burden of Disease study 2017 were analyzed. Age-period-cohort modeling was performed to investigate the trends in untreated caries that may be of value to policymakers. Analyses were conducted in 2019-2020. RESULTS: Prevalence of untreated caries in permanent teeth decreased steadily before 2010; after which, an increasing trend was noted without the signs of plateauing (age-adjusted annual percentage change, 1993-2017: -0.54%, 95% CI= -0.75%, -0.33%; declining period RR, 1993-2017: p=6.33 × 10-9; declining cohort RR, 1993-2017: p=3.46 × 10-6). Although untreated caries prevalence declined overall among multiple age groups (p<0.05), an increase in prevalence after 2010 was noted. This was driven by the deteriorating oral health condition in recent birth cohorts aged <25 years. Estimates of the longitudinal age trend (incidence: -0.013, 95% CI= -0.015, -0.011; prevalence: -0.0038, 95% CI= -0.0060, -0.0015) suggested that the highest untreated caries incidence and prevalence rate were both observed among young adults aged 20-24 years. No differences between incidence and prevalence of untreated caries were observed among adults aged >55 years (p>0.05). CONCLUSIONS: The increased burden of untreated caries in China after 2010 is driven by those aged <25 years. Untreated caries data from the Global Burden of Disease study are a valid complement to the data from the Chinese National Oral Health Epidemiology Surveys.

Developmental shape changes in facial morphology: Geometric morphometric analyses based on a prospective, population-based, Chinese cohort in Hong Kong.

BACKGROUND: Thorough understanding of developmental changes of human facial shape is lacking. The present study aimed to evaluate developmental shape changes of facial morphology based on a prospective, population-representative, Chinese cohort in Hong Kong. METHODS: A population-representative sample of Chinese in Hong Kong was followed. Serial facial images of over 260 participants were obtained at age 12, 15, and 18 years. Facial landmarks were digitized and the corresponding coordinates were submitted for Generalized Procrustes Analysis. The resultant Procrustes shape coordinates, which captured shape information encoded by the facial landmarks, were then used for statistical shape analyses. RESULTS: Small but significant developmental changes in mean facial shape were observed (p < 0.0001 for all pairwise comparisons). Significant age-related changes in the magnitude of variance of facial shape were also observed (p < 0.05). Phenotypic growth trajectories representing developmental shape changes were similar in size (p > 0.05) between sexes but differed in direction (p < 0.05) in shape space and trajectory shape (p < 0.05). The magnitude of shape differences between sexes remained constant from 12 to 18 years. Results of frontal facial shape analyses after removing the effect of allometry were similar to results obtained before removal of allometry. For lateral facial configurations, allometric trajectories among the age-by-sex groups were similar in slope (p > 0.05) but varied in directions in the multidimensional shape space. CONCLUSIONS: Our findings suggested significant age-related changes in facial shape and provided a dynamic view of developmental changes in sexual dimorphism of facial shape. Allometry contributed minimally to developmental changes in frontal facial shape. In addition, the allometric trajectories for lateral facial configurations were similar in rate of shape change but differed in their directions in shape space.

Adolescent dental arch development among Southern Chinese in Hong Kong: a geometric morphometric approach.

This study aimed to investigate changes in types of dental arch form during adolescence and explore adolescent changes in size and form of dental arch. Hong Kong Chinese were recruited and digital dental arch models were obtained at ages 12, 15, and 18 years. Geometric morphometrics was used to investigate adolescent changes of dental arch form. There were 225 participants from whom digital models at all three age periods were available. Three types of dental arch form were identified through clustering. Significant changes (p < 0.001) in types of dental arch form were noted during age 12-18 years. During age 12-18 years, significant changes in centroid size and form of dental arch were observed (p < 0.001). No significant changes were observed during 15-18 years. Adolescent changes of dental arch form occur primarily during age 12-15 years, whereas dental arch form was relatively stable during age 15-18 years.

Trends and Patterns of Disparities in Burden of Lung Cancer in the United States, 1974-2015.

Background: Although lung cancer incidence and mortality have been declining since the 1990s, the extent to which such progress has been made is unequal across population segments. Updated epidemiologic data on trends and patterns of disparities are lacking. Methods: Data on lung cancer cases and deaths during 1974 to 2015 were extracted from the Surveillance, Epidemiology, and End Results program. Age-standardized lung cancer incidence and mortality and their annual percent changes were calculated by histologic types, demographic variables, and tumor characteristics. Results: Lung cancer incidence decreased since 1990 (1990 to 2007: annual percent change, -0.9 [95% CI, -1.0%, -0.8%]; 2007 to 2015: -2.6 [-2.9%, -2.2%]). Among adults aged between 20 and 39 years, a higher incidence was observed among females during 1995 to 2011, after which a faster decline in female lung cancer incidence (males: -2.5% [-2.8%, -2.2%]; females: -3.1% [-4.7%, -1.5%]) resulted in a lower incidence among females. The white population had a higher incidence than the Black population for small cell carcinoma since 1987. Black females were the only group whose adenocarcinoma incidence plateaued since 2012 (-5.0% [-13.0%, 3.7%]). A higher incidence for squamous cell carcinoma was observed among Black males and females than among white males and females during 1974 to 2015. After circa 2005, octogenarians and older patients constituted the group with the highest lung cancer incidence. Incidence for localized and AJCC/TNM stage I lung cancer among octogenarians and older patients plateaued since 2009, while mortality continued to rise (localized: 1.4% [0.6%, 2.1%]; stage I: 6.7% [4.5%, 9.0%]). Conclusions: Lung cancer disparities prevail across population segments. Our findings inform effective approaches to eliminate lung cancer disparities by targeting at-risk populations.

A meta-analysis of emotional disorders as possible risk factors for chronic periodontitis.

The aim of the present meta-analysis was to evaluate scientific evidence on the association between emotional disorder (depression and anxiety) and chronic periodontitis. An overall electronic literature search in PubMed, ISI Web of Science, Cochrane Library, and China National Knowledge Infrastructure was undertaken up to November 2017. Newcastle-Ottawa scale was applied to ascertain the validity of each eligible study. Stata statistical software was used to perform meta-analysis. The strength of the association between periodontitis and emotional disorder was measured by odds ratios (ORs) with their 95% confidence intervals (95% CIs). Subgroup analysis and sensitivity analysis were performed. Publication bias was assessed through funnel plots and Begger's test. A total of 14 eligible articles were included in the meta-analysis, 6 of them were focused exclusively on depression, whereas 8 studies investigated both depression and anxiety. There was significant association between emotional disorder and chronic periodontitis (OR = 1.54, 95% CI = 1.27-1.86). Sensitivity analyses confirmed the stability of the present results. No evidence of asymmetry was observed in Begger's test. This meta-analysis demonstrates significant association between emotional disorder (including anxiety and depression) and chronic periodontitis. Nevertheless, the result should be interpreted with caution because of the potential bias and confounding in the included studies.

A longitudinal study of facial growth of Southern Chinese in Hong Kong: Comprehensive photogrammetric analyses.

INTRODUCTION: Existing studies on facial growth were mostly cross-sectional in nature and only a limited number of facial measurements were investigated. The purposes of this study were to longitudinally investigate facial growth of Chinese in Hong Kong from 12 through 15 to 18 years of age and to compare the magnitude of growth changes between genders. METHODS AND FINDINGS: Standardized frontal and lateral facial photographs were taken from 266 (149 females and 117 males) and 265 (145 females and 120 males) participants, respectively, at all three age levels. Linear and angular measurements, profile inclinations, and proportion indices were recorded. Statistical analyses were performed to investigate growth changes of facial features. Comparisons were made between genders in terms of the magnitude of growth changes from ages 12 to 15, 15 to 18, and 12 to 18 years. For the overall face, all linear measurements increased significantly (p < 0.05) except for height of the lower profile in females (p = 0.069) and width of the face in males (p = 0.648). In both genders, the increase in height of eye fissure was around 10% (p < 0.001). There was significant decrease in nasofrontal angle (p < 0.001) and increase in nasofacial angle (p < 0.001) in both genders and these changes were larger in males. Vermilion-total upper lip height index remained stable in females (p = 0.770) but increased in males (p = 0.020). Nasofrontal angle (effect size: 0.55) and lower vermilion contour index (effect size: 0.59) demonstrated large magnitude of gender difference in the amount of growth changes from 12 to 18 years. CONCLUSIONS: Growth changes of facial features and gender differences in the magnitude of facial growth were determined. The findings may benefit different clinical specialties and other nonclinical fields where facial growth are of interest.

Longitudinal changes in developmental defects of enamel.

OBJECTIVES: Epidemiological studies on developmental defects of enamel (DDE) have focused on its potential contributory factors and prevalence while there is limited evidence on the longitudinal changes in the epidemiological profile of DDE. Thus, the objective of this longitudinal study was to investigate whether any type of DDE changes with time. METHODS: A total of 668 participants were initially recruited in 2010, and 432 participants were successfully followed up and examined for DDE both at the age of 12 in 2010 and 15 in 2013. The central incisor, lateral incisor and first molar in each quadrant were chosen as index teeth and were examined 'wet' by two trained and calibrated examiners using the modified FDI (DDE) Index. RESULTS: The mouth prevalence and tooth prevalence of 'any defect' showed a significant decrease from 2010 to 2013 (P < 0.001). This was predominantly due to the decrease in diffuse opacities (P < 0.001). Significant difference in the distribution of the extent of DDE was also found for diffuse opacities at both the participant and tooth levels irrespective of the types of tooth (P < 0.0001). Median extent score for diffuse opacities in 2013 was lower than those in 2010 at both participant and tooth level irrespective of the types of tooth (P < 0.001). CONCLUSIONS: Diffuse opacities, in terms of prevalence and severity, did fade out over time. The observed overall change in DDE was due to the dominating effect of diffuse opacities over demarcated opacities and hypoplasia.

A population survey of early factors associated with permanent tooth emergence: findings from a prospective cohort study.

OBJECTIVES: Studies investigating influencing factors of permanent tooth eruption/emergence have primarily focused on anthropometric measurements while less attention has been paid to the effect of perinatal factors. We aimed to explore early factors associated with eruption status of permanent teeth among 12-year-olds through a population-representative prospective cohort. METHODS: A community sample of Hong Kong children born in 1997 was obtained by random sampling from local secondary schools. Participants' background information including birth characteristics, prenatal and early childhood exposures, family socioeconomic status and medical records was prospectively collected. Clinical examination of tooth emergence was conducted in 2010. Children were divided into complete emergence (of 28 permanent teeth) and partial emergence groups based on clinical examinations. Bivariate analyses were used to assess the association of tooth emergence status with each putative predictor. Unadjusted and adjusted logistic regression models were applied to select the best predictors for tooth emergence status at age 12. RESULTS: Complete background information and clinical data were available from 514 children (76.9% of the invited participants). Bivariate analyses showed that the average birthweight in the partial emergence group was significantly lower than the complete emergence group (mean difference 0.2 kg, P = 0.006). The finding was confirmed by logistic regression analyses. In the adjusted regression model, it was found that for every 1 kilogram increase in birthweight, the odds of having partial emergence would be lowered by 0.49 (odds ratio 0.49, P = 0.006). CONCLUSIONS: Birthweight is associated with status of permanent tooth emergence at 12 years of age, as observed from a population-representative sample of Hong Kong children.

Northern Chinese dental ages estimated from southern Chinese reference datasets closely correlate with chronological age.

While northern and southern Chinese are genetically correlated, there exists notable environmental differences in their living conditions. This study aimed to evaluate validity of the southern Chinese reference dataset for dental age estimation applied to northern Chinese. Dental panoramic tomographs of 437 northern Chinese aged 3 to 21 years were analysed. All the left maxillary and mandibular permanent teeth plus the 2 third molars on the right side were scored based on Demirjian's classification of tooth development stages. Mean and standard error of dental age were obtained for each tooth development stage, followed by random effect meta-analysis for mean dental age estimation. Validity of the method was examined through measures of agreement (95% limits of agreement, standard error of measurement, and Lin's concordance correlation coefficient) and measure of reliability (Intraclass correlation coefficient). On average, the estimated dental age overestimated chronological age by only around 1 month in both females and males. The Intraclass correlation coefficient values were 0.99 for both sexes, suggesting excellent reliability of the method. Reference dataset for dental age estimation developed on the basis of southern Chinese was applicable for use among the northern Chinese.

Anthropometric measurements and periodontal diseases in children and adolescents: a systematic review and meta-analysis.

The aim of this systematic review was to identify and summarize evidence of the association between anthropometric measurements and periodontal status in children and adolescents. We searched PubMed, Institute for Scientific Information Web of Knowledge, Cochrane Library, and 7 additional databases, following the guidance of Preferred Reporting Items for Systematic Reviews and Meta-Analyses, up to December 2014. Observational studies reporting data on the association between anthropometric measurements and periodontal diseases in 2-18-y-old participants were included. An initial search identified 4191 papers; 278 potentially effective studies (k = 0.82) and 16 effective studies (k = 0.83) were included after screening. The mean quality of evidence among the studies was 20.3, according to the Strengthening the Reporting of Observational studies in Epidemiology checklist (k = 0.79). Meta-analyses showed that obesity (measured by body mass index) was significantly associated with visible plaque index (OR: 4.75; 95% CI: 2.42, 9.34), bleeding on probing (OR: 5.41; 95% CI: 2.75, 10.63), subgingival calculus (OR: 3.07; 95% CI: 1.10, 8.62), probing depth (OR: 14.15; 95% CI: 5.10, 39.25) and flow rate of salivary secretion (standardized mean difference: -0.89; 95% CI: -1.18, -0.61). However, various results were reported in the effective studies that were not included in meta-analyses. In conclusion, obesity is associated with some signs of periodontal disease in children and adolescents. Further studies with a comprehensive prospective cohort design and more potential variables are recommended.

Inter-Ethnic/Racial Facial Variations: A Systematic Review and Bayesian Meta-Analysis of Photogrammetric Studies.

BACKGROUND: Numerous facial photogrammetric studies have been published around the world. We aimed to critically review these studies so as to establish population norms for various angular and linear facial measurements; and to determine inter-ethnic/racial facial variations. METHODS AND FINDINGS: A comprehensive and systematic search of PubMed, ISI Web of Science, Embase, and Scopus was conducted to identify facial photogrammetric studies published before December, 2014. Subjects of eligible studies were either Africans, Asians or Caucasians. A Bayesian hierarchical random effects model was developed to estimate posterior means and 95% credible intervals (CrI) for each measurement by ethnicity/race. Linear contrasts were constructed to explore inter-ethnic/racial facial variations. We identified 38 eligible studies reporting 11 angular and 18 linear facial measurements. Risk of bias of the studies ranged from 0.06 to 0.66. At the significance level of 0.05, African males were found to have smaller nasofrontal angle (posterior mean difference: 8.1°, 95% CrI: 2.2°-13.5°) compared to Caucasian males and larger nasofacial angle (7.4°, 0.1°-13.2°) compared to Asian males. Nasolabial angle was more obtuse in Caucasian females than in African (17.4°, 0.2°-35.3°) and Asian (9.1°, 0.4°-17.3°) females. Additional inter-ethnic/racial variations were revealed when the level of statistical significance was set at 0.10. CONCLUSIONS: A comprehensive database for angular and linear facial measurements was established from existing studies using the statistical model and inter-ethnic/racial variations of facial features were observed. The results have implications for clinical practice and highlight the need and value for high quality photogrammetric studies.

Risk factors of developmental defects of enamel--a prospective cohort study.

BACKGROUND AND OBJECTIVE: Current studies on the aetiology of developmental defects of enamel (DDE) are subject to recall bias because of the retrospective collection of information. Our objective was to investigate potential risk factors associated with the occurrence of DDE through a prospective cohort study. METHODS: Using a random community sample of Hong Kong children born in 1997, we performed a cohort study in which the subjects' background information, medical and dental records were prospectively collected. A clinical examination to identify DDE was conducted in 2010 when the subjects were 12 years old. The central incisor, lateral incisor and first molar in each quadrant were chosen as the index teeth and were examined 'wet' by two trained and calibrated examiners using the modified FDI (DDE) Index. RESULTS: With a response rate of 74.9%, the 514 examined subjects had matched data for background information. Diffuse opacites were the most common type of DDE. Of the various possible aetiological factors considered, only experience of severe diseases during the period 0-3 years was associated with the occurrence of 'any defect' (p = 0.017) and diffuse opacities (p = 0.044). The children with experience of severe diseases before 3 years of age were 7.89 times more likely to be affected by 'any defect' compared with those who did not have the experience (OR 7.89; 95% CI 1.07, 58.14; p = 0.043). However, after adjusting for confounding factors, the association no longer existed. CONCLUSION: No variables could be identified as risk factors of DDE in this Hong Kong birth cohort.