Directed Acyclic Graphs for Oral Disease Research

Towards the integration of prevention and control of oral diseases within child primary healthcare: The case of Peru

OBJECTIVES

The Peruvian public health norm of primary healthcare (PHC) for growth and development medical check-ups (CRED, Spanish acronym) of children under 5 years of age was updated in 2017 with the inclusion of interdisciplinary prevention and control actions for oral diseases, such as dentist referral. The aim of this study was to explore the association between CRED and oral health services utilization (OHSU), throughout the heterogeneous Peruvian territory.

METHODS

A population-based cross sectional study was conducted using the 2021 Demographic and Family Health Survey of Peru and included data from 15 836 children aged 12-59 months. Poisson generalized linear models were used to evaluate the association between any CRED and OHSU, in the 6 months prior to the survey, including sociodemographic characteristics of the children and their mothers as confounding variables. A possible effect modification by natural region of residence (Metropolitan Lima/rest of the Coast/Highlands/Jungle) was evaluated. To examine the robustness of the regression model, a sensitivity analysis was performed using the cumulative number of CRED.

RESULTS

Children who had at least one CRED were almost twice as likely to report OHSU (aPR: 1.95; 95% CI: 1.73-2.21), which was greater in the regions of rest of the Coast (aPR: 2.56; 95% CI: 2.00-3.17) and Jungle (aPR: 2.03; 95% CI: 1.64-2.56). The sensitivity analysis showed consistent results for the association CRED-OHSU. Nevertheless, within the last 6 months, attendance at CRED and OHSU were only achieved by 43.7% and 13.7% of the children respectively.

CONCLUSIONS

Integrating oral health into Peruvian Child PHC seems to be a promising public health intervention to increase children's OHSU. For a greater scope, it is crucial to drive greater attendance at CRED and continuous monitoring and strengthening of CRED-based oral health promotion in all Peruvian natural regions with an equity-focused approach.

Factors affecting the quality of life of patients with medication-related osteonecrosis of the jaw during treatment: A quality-of-life survey and causal analysis

This prospective cohort study aimed to investigate the impact of medication-related osteonecrosis of the jaw (MRONJ) on health-related quality of life (HRQOL) and oral health-related QOL (OHRQOL) and the association between the downstaging of MRONJ and OHRQOL. The HRQOL and OHRQOL of 44 patients with MRONJ were assessed using the SF-36v2 and the General Oral Health Assessment Index (GOHAI), respectively. Treatment was performed in accordance with the AAOMS position paper (2014). The SF-36v2 and GOHAI scores at the beginning of the survey were used to evaluate the impact of MRONJ on QOL. Potential confounders affecting the association between downstaging and QOL improvement were selected using directed acyclic graphs. Multiple regression analysis was performed to evaluate causal inferences. HRQOL scale scores declined below the national average. The three-component summary score (3CS), comprising the physical component summary (PCS), mental component summary (MCS), and role/social component summary (RCS), revealed that performance status and primary disease significantly affected the PCS and RCS (P = 0.005 and P < 0.001, respectively) and PCS and MCS (P = 0.024 and P = 0.003, respectively). The MRONJ stage did not influence the 3CS; however, OHRQOL declined in a stage-dependent manner (P = 0.005). Downstaging of MRONJ was independently associated with the improvement rate of the total GOHAI scores after adjusting for variables (P = 0.045). The HRQOL of patients with MRONJ declined; however, this may depend on the underlying disease status rather than the MRONJ stage. Improvement of the disease status can potentially predict an improvement in OHRQOL, regardless of the treatment modality.

Functional oral status and oral health-related quality of life in community-dwelling older adults in Singapore

OBJECTIVES

The objectives were to investigate the association between oral functional status (defined by the number of functional teeth and functional occluding units [FOUs]) on oral health-related quality of life (OHRQoL). It also aimed to determine if dentures could compensate for the loss of FOUs in terms of OHRQoL in community-dwelling older adults in Singapore.

METHODS

Community-dwelling older adults, aged 60 years and above, were recruited from a community-based oral health functional screening programme from 1 May 2018 to 31 December 2019. During the screening, an Oral Health Impact Profile-14 (OHIP-14) questionnaire and oral examination were administered. Statistical analysis was performed using the chi-square test, univariate logistic regression and multivariate predictive modelling.

RESULTS

Data from 1037 participants were analysed (52% female; mean age 71.5 (SD 7.15)). The mean OHIP-14 score was 4.5 ± 7.2. The OHIP-14 scores were significantly associated with the number of functional teeth and the number of FOUs (p < .001). Having at least 20 functional teeth or 10 FOUs was associated with a significantly lower OHIP-14 score. Those with no FOUs had higher OHIP-14 scores compared to those with at least 10 FOUs, even in the presence of a satisfactory denture.

CONCLUSION

Maintaining at least 20 functional teeth or 10 FOUs was associated with better OHRQoL among community-dwelling older adults in Singapore. Dentures may have limited compensatory ability in terms of replacing natural functional occlusal units and maintaining OHRQoL.

Temporal trends and the association between self-rated oral health and falls in community-dwelling older adults in South Korea: a secondary analysis of survey data

OBJECTIVE

This study aims to examine temporal trends and the association between falls and self-rated oral health (SROH) status in community-dwelling older Korean adults.

DESIGN

Secondary analysis of a serial cross-sectional study.

METHODS

We analysed biennial data from 314 846 older adults in South Korea from 2011 to 2019 using data from the Korea Community Health Survey. Self-reported fall experience data came from the injury questionnaire question, 'Have you fallen in the past year (slipping, tripping, stumbling and falling)?'. For SROH, the participants were asked, 'How do you feel about your oral health, such as teeth and gums, in your own opinion?'. The association between SROH and falls was examined using a weighted multivariable logistic regression model adjusted for sociodemographic characteristics, health status and behaviours, and psychological factors.

RESULTS

Those who reported poor SROH had a lower declining slope than the other groups, although all groups showed a significantly decreasing trend in both men and women from 2011 to 2019 (p for trend<0.001). Older adults who reported having poor SROH had a more significant history of fall accidents than the good SROH groups, controlling for potential confounding variables (adjusted OR 1.16 (95% CI 1.10 to 1.21) in men; adjusted OR 1.17 (95% CI 1.13 to 1.21) in women).

CONCLUSIONS

Older adults with poor SROH, especially women, had more fall accidents, making them a priority target for fall prevention strategies. This study suggests considering SROH status when identifying fall risk factors in community-dwelling older adults.

Preventive dental service use and oral health-related quality of life in Brazilian older adults

BACKGROUND

Information on the use of preventive dental services and associated variables is needed to guide policy for the old adult population and consequently promote better oral health-related quality of life (OHRQoL).

OBJECTIVE

To investigate the association between preventive dental service use and OHRQoL by older Brazilians.

MATERIALS AND METHODS

This cross-sectional study was carried out using the baseline data of participants of the Brazilian Longitudinal Stud of Aging (ELSEI-Brazil) who were aged 60 years or more. Associations with the use of preventive dental services were carried out using Poisson regression models with robust variance, adjusting for confounders.

RESULTS

The final sample consisted of 5432 older adults. Almost all (90.7%) participants reported not having sought preventive dental services in the last year. Individuals who used dental services for prevention had fewer impacts on their OHRQoL (RR: 0.74; [95% CI: 0.57-0.97]).

CONCLUSION

Preventive dental service use is associated with a better OHRQoL in older Brazilians. Policies to improve access to preventive dental services may result in improved OHRQoL in this age group.

The association between trypsin-like protease activity in the oral cavity and kidney function in Japanese workers

AIM

To evaluate the association between trypsin-like protease (TLP) activity in the oral cavity as an indicator of periodontal health status and kidney function in Japanese workers.

MATERIALS AND METHODS

This cross-sectional study included 1117 Japanese workers (mean age = 43.8 years). Tongue-swab TLP activity was quantified as a* value (the redness intensity of the matrix disc of the TLP activity assessment kit; a larger value indicates more intense enzymatic activity in the samples and poorer periodontal health status). Kidney function was assessed using the estimated glomerular filtration rate (eGFR; a lower value indicates poorer kidney function). We performed ordinal logistic regression analyses to assess the association of the a* value with three eGFR categories: ≥90, 60-89 and <60 mL/min/1.73 m2 .

RESULTS

The prevalence for each eGFR category was as follows: ≥90 (31.6%), 60-89 (63.8%) and <60 mL/min/1.73 m2 (4.6%). After adjusting for potential confounders, the a* value was found to be significantly associated with reduced kidney function. The multivariable-adjusted odds ratio (95% confidence interval) for reduced kidney function was 1.12 (1.02-1.22) per unit increase in the a* value.

CONCLUSIONS

Higher TLP activity was associated with reduced kidney function in Japanese workers.

Periodontitis and systemic inflammation as independent and interacting risk factors for mortality: evidence from a prospective cohort study

BACKGROUND

Recent studies have highlighted the role of low-grade systemic inflammation in linking periodontitis to cardiovascular disease (CVD) outcomes, but many aspects remain unclear. This study examines the independent and reciprocal associations of periodontitis and low-grade systemic inflammation with all-cause and CVD mortality in a large-scale cohort.

METHODS

A total of 3047 participants from the prospective, population-based Study of Health in Pomerania (SHIP-START) were followed for a period of 13.0 ± 2.4 years. For the association between various inflammation/periodontitis measures and mortality, hazard ratios (HRs) were obtained from covariate-adjusted Cox proportional hazards models. Interactions were analysed in joint models: on the multiplicative scale, HRs were reported and on the additive scale, relative excess risks due to interaction (RERI) were calculated. Subject and variable-specific interval records were used to account for time-varying exposures and covariates.

RESULTS

During the observation period, 380 (12.5%) individuals died from CVD (n = 125) or other causes (n = 255). All markers of periodontitis and inflammation showed apparent associations with all-cause mortality (HRs per SD-increase: mean PPD: 1.068 (95% confidence interval (CI): 0.988-1.155), mean CAL: 1.205 (95% CI: 1.097-1.323), missing teeth: 1.180 (95% CI: 1.065-1.307), periodontitis score: 1.394 (95% CI: 1.202-1.616), leukocytes: 1.264 (95% CI: 1.163-1.374), fibrinogen: 1.120 (95% CI: 1.030-1.218), CRP: 1.231 (95% CI: 1.109-1.366), inflammation score: 1.358 (95% CI: 1.210-1.523)). For CVD mortality, all PPD related variables showed significant associations. Interaction modelling revealed some variation with respect to mortality type and exposure combinations. On the additive scale, RERIs for periodontitis score and inflammation score implied 18.9% and 27.8% excess mortality risk for all-cause and CVD mortality, respectively. On the multiplicative scale, the HRs for interaction were marginal.

CONCLUSIONS

Both periodontitis and inflammation were significantly associated with all-cause mortality and CVD mortality. On the additive scale, a substantial excess risk was observed due to the interaction of periodontitis and inflammation, suggesting that the greatest treatment benefit may be achieved in patients with both periodontitis and high systemic inflammation. As periodontal therapy has been reported to also reduce systemic inflammation, the possibility of a reduction in CVD mortality risk by anti-inflammatory treatments, including periodontal interventions, seems worthy of further investigation.

Association between the second- and fourth-digit ratio and oral squamous cell carcinoma

OBJECTIVES

Using an established proxy measure of intra-utero testosterone and estrogen levels-the ratio of second- and fourth-digit lengths-we estimated its association with the oral cancer risk among a population from Southern India.

MATERIAL AND METHODS

In a hospital-based case-control study, incident oral cancer cases (N = 350) and non-cancer controls (N = 371), frequency-matched by age and sex, were recruited from two major referral hospitals in Kerala, India. Structured interviews collected information on several domains of exposure via detailed life course questionnaires. Digit lengths were measured using a ruler in a standardized manner. Unconditional logistic regression was performed to estimate the odds ratios and 95% confidence intervals.

RESULTS

Second- and fourth-digit ratio lower than 1, which indicates relatively higher intra-utero level of testosterone and lower intra-utero level of estrogen, was associated with higher oral cancer risk (OR = 1.60, 95% CI: 1.02-2.52), after accounting for several confounders.

CONCLUSION

Our findings suggest that intra-utero hormonal levels measured by second- and fourth-digit ratio are associated with oral cancer risk. Further studies in different population should confirm these results.

Quantitative Assessment of Systematic Bias: A Guide for Researchers

Observational research provides valuable opportunities to advance oral health science but is limited by vulnerabilities to systematic bias, including unmeasured confounding, errors in variable measurement, or bias in the creation of study populations and/or analytic samples. The potential influence of systematic biases on observed results is often only briefly mentioned among the discussion of limitations of a given study, despite existing methods that support detailed assessments of their potential effects. Quantitative bias analysis is a set of methodological techniques that, when applied to observational data, can provide important context to aid in the interpretation and integration of observational research findings into the broader body of oral health research. Specifically, these methods were developed to provide quantitative estimates of the potential magnitude and direction of the influence of systematic biases on observed results. We aim to encourage and facilitate the broad adoption of quantitative bias analyses into observational oral health research. To this end, we provide an overview of quantitative bias analysis techniques, including a step-by-step implementation guide. We also provide a detailed appendix that guides readers through an applied example using real data obtained from a prospective observational cohort study of preconception periodontitis in relation to time to pregnancy. Quantitative bias analysis methods are available to all investigators. When appropriately applied to observational studies, findings from such studies can have a greater impact in the broader research context.

Oral health-related quality of life of older Australian men

OBJECTIVES

The aims of this study were to assess oral health-related quality of life (OHRQoL) in a cohort of older Australian men and explore the association between their general health conditions, socio-demographic factors and OHRQoL.

METHODS

The Concord Health and Ageing in Men Project (CHAMP) is a cohort study of the health of a representative sample of Australian men, initiated in 2005-2006 with an initial sample of 1705 men 70 years or over. Participants completed a self-administered health and socio-demographic questionnaire and attended an interview and clinical assessment at baseline and each of three follow-up assessments. Information on oral health and responses to the Oral Health Impact Profile (OHIP-14) were collected in the 4th follow-up in which 778 men completed the OHIP-14 questionnaire and 614 men had a dental assessment. The prevalence of oral health impact was defined as a response of fairly often or very often to one or more of the OHIP-14 questions. Mean OHIP-14 scores were calculated for the 14 questions and used as the dependent variable in the regression analyses. Zero-inflated Poisson regression was used to estimate prevalence rate ratios (PRR).

RESULTS

Only 10% of men presented oral health impacts. In multivariate regression modelling, being born in Italy/Greece (PRR: 2.16, 95% CI: 1.93-2.42) or in other countries (PRR: 2.12, 95% CI: 1.89-2.38), having poor self-rated general health (PRR: 1.38, 95% CI: 1.24-1.53), having poor mental wellbeing (PRR: 1.14, 95% CI: 1.04-1.24), having ≥6 depressive symptoms (PRR: 1.18, 95% CI: 1.05-1.32), being a current smoker (PRR: 1.34, 95% CI: 1.06-1.70) and having more decayed tooth surfaces (PRR:1.01, 95% CI: 1.00-1.02) were associated with higher impact scores.

CONCLUSIONS

Overall, older Australian men exhibit good oral health-related quality of life. The inter-relationship between perceptions of general health and well-being, health and oral health variables and social background supports policy objectives of closer integration of general health and oral health services for older Australian men.

Implications of sleep disorders for periodontitis

PURPOSE

Periodontitis is a chronic inflammatory disease caused by multi-factors. Sleep is a natural physiologic process, and the sleep duration, quality, and patterns might be associated with periodontitis. Meanwhile, periodontitis might in turn induce systemic inflammation and thus impact sleep in different ways as well.

METHODS

To investigate the bidirectional relationship between sleep disorder and periodontitis, a literature search was conducted to reveal the interaction and possible mechanism between these two diseases.

RESULTS

The results show that sleep disorders can affect the progression of periodontitis via some pathomechanisms, and periodontitis also has a reverse impact on sleep.

CONCLUSION

Although the epidemiologic and clinical trials found the possible associations between sleep disorder and periodontitis, their relationship is still not that explicit. Further studies are warranted to shed light on them, to improve preventive health care.

Sex hormones associated with temporomandibular pain on palpation in male adolescents-Results of the epidemiologic LIFE child study

OBJECTIVE

This study aimed to investigate whether the sex steroid precursor hormone dehydroepiandrosterone sulphate (DHEA-S), sex hormone-binding globulin (SHBG) and testosterone (TT) are associated with temporomandibular (TM) pain on palpation in male adolescents.

METHODS

Out of the LIFE Child study dataset containing 1022 children and adolescents aged 10-18 years (496 males, 48.5%), we used a subsample of 273 male adolescents (mean age: 13.8 ± 2.3 years) in advanced pubertal development (PD) to analyse the association between hormones and TM pain. The Tanner scale was applied to describe the stage of PD. Pain on palpation of the temporalis and masseter muscles and the TM joints (palpation pain) was assessed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Serum levels of sex hormones (DHEA-S, SHBG and TT) were determined using standardised laboratory analyses. Free TT was estimated from the ratio between TT and SHBG (free androgen index[FAI]). We calculated the risk of perceived positive palpation pain for male participants as a function of hormone levels (DHEA-S, FAI) taking into account age and body mass index (BMI).

RESULTS

Among more developed (Tanner stage 4-5) male adolescents, 22.7% (n = 62) reported palpation pain in the TM region. In these participants, FAI levels were approximately half that of individuals without such pain (p < .01). DHEA-S levels were about 30% lower in the pain group (p < .01). In multivariable regression analyses, the odds ratio (OR) for pain on palpation decreased to 0.75 (95% confidence interval [CI]: 0.57-0.98) per 10 units of FAI level compared to those without pain, after controlling for the effects of age and adjusted BMI. We observed the same effect for this subgroup per unit of DHEA-S serum level (OR = 0.71; 95% CI: 0.53-0.94).

CONCLUSION

At subclinical lower levels of serum free TT and DHEA-S, male adolescents are more likely to report pain on standardised palpation of the masticatory muscles and/or TM joints. This finding supports the hypothesis that sex hormones may influence pain reporting.

Evolution and development of methodologies in social and behavioural science research in relation to oral health

The aim of this introductory paper is to provide an overview of key methodological developments in social and behavioural research in oral health. In the first section, we provide a brief historical perspective on research in the field. In the second section, we outline key methodological issues and introduce the seven papers in the theme. Conceptual models can contextualize research findings and address the 'why' and 'how' instead of 'what' and 'how many'. Many models exist, albeit they need to be evaluated (and adapted) for use in oral health research and in specific settings. The increasing availability of big data can facilitate this with data linkage. Through data linkage, it is possible to explore and understand in a broader capacity the array of factors that influence oral health outcomes and how oral health can influences other factors. With advances in statistical approaches, it is feasible to consider casual inferences and to quantify these effects. There is a need for not only individual efforts to embrace causal inference research but also systematic and structural changes in the field to yield substantial results. The value of qualitative research in co-producing knowledge with and from human participants in addressing 'the how' and 'the why' factors is also key. There have been calls to employ more sophisticated qualitative methods together with mixed methods approaches as ways of helping to address the complex or Wicked Problems in population oral health. In the final section, we outline possible future methodological directions in social and behavioural oral health research including participatory approaches and the development of core outcome sets. Our overriding goal in the paper is to facilitate a critical debate in relation to methodological issues which can be used to improve understanding and generate knowledge in population oral health and that this, in turn, will help inform oral health policy and practices.

Behavioural and cognitive-behavioural theories in oral health research: Current state and future directions

OBJECTIVES

Behavioural and cognitive-behavioural theories, models and frameworks have been incorporated for decades in behavioural and social oral health sciences, oral health care, and education of dentists, hygienists, and other oral healthcare professionals.

METHODS

While a myriad of these conceptualizations have been incorporated in this work, there are six of them that have had the greatest impact in the oral health arena: (a) Health Belief Model; (b) Theory of Reasoned Action, Theory of Planned Behavior and Integrated Behavioral Model, which are considered in unison; (c) Social Learning Theory and Social Cognitive Theory which are considered together; (d) Transtheoretical Model/Stages of Change Model; (e) Salutogenesis Model/Theory and Sense of Coherence Framework; and the (f) Behavior Change Wheel, Capability-Opportunity-Motivation-Behavior Model and Theoretical Domains Framework, which are categorized together.

RESULTS

An analysis of nomenclature (i.e. theories, models, frameworks and conceptualizations) is provided in the context of a description of each of these theories and models, with discussion about their aspects that particularly relate to oral health. Additionally, a quantitative, longitudinal view is provided of the frequency of use of these theories and models in the oral health arena. Given the benefits of theory-based intervention development, dissemination and implementation, it is important to consider these theories and models in a collective context.

CONCLUSIONS

At a basic level, these theories and models help in identifying and acting on mechanisms, both of behaviour itself and behaviour change. Future directions are discussed in terms of need for theory evolution and development.

Do cutaneous human papillomavirus genotypes affect head and neck cancer? Evidence and bias-correction from a case-control study

BACKGROUND

Three genera of human papillomavirus (HPV) infect the oral cavity and oropharynx- alpha (α), beta (β) and gamma (γ). While α-HPV infection is an established risk factor for head and neck cancers (HNC), the role of other genera remains unclear. We aimed to estimate the effect of α-, β-, γ-HPV on HNC using a hospital-based case-control study.

METHODS

We recruited incident HNC cases (396) and controls (439), frequency-matched by age and sex from four main referral hospitals in Montreal, Canada. We collected information on sociodemographic and behavior characteristics using in-person interviews, and tested rinse, brush and tumor specimens for HPV genotypes. We estimated adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the effect of HPV on HNC using logistic regression, adjusting for confounding. We conducted probabilistic bias analysis to account for potential exposure misclassification, selection bias, and residual confounding.

RESULTS

α-HPV genus had a strong effect on HNC, particularly HPV16 (aOR=22.6; 95% CI: 10.8, 47.2). β-HPV was more common among controls (aOR=0.80; 95% 0.57, 1.11). After adjustment for HPV16, we found weaker evidence for γ-HPV (aOR= 1.29; 95% CI: 0.80, 2.08). Combined bias analyses for HPV16 increased the strength of the point estimate, but added imprecision (aOR=54.2, 95% CI: 10.7, 385.9).

CONCLUSIONS

α-HPV, especially HPV16, appears to increase the risk for HNC, while there is little evidence for an effect of β- or γ-HPV. β-HPV may have a preventive effect, while γ-HPV may increase the risk of HNC, although to a lesser extent than that of α-HPV. Results for cutaneous HPV were imprecise and less conclusive. Due to possible epidemiologic biases, the true relation between HPV and HNC could be underestimated in the literature. Further improvement in current methods and more studies of the biologic mechanisms of the three genera in HNC development are warranted.

Causal Inference: Onward and Upward!

When announcing the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2021, the Royal Swedish Academy emphasized how conclusions about cause and effect can be drawn from natural experiments. But what can dental research learn from this? The economist’s toolbox provides a number of methods for causal inference from observational data such as instrumental variables, regression discontinuity designs, or difference-in-differences analyses. Although the relevance of improving causal inference in dental research has repeatedly been highlighted in recent years, dental research still seems to reveal major room for improvement in the application of such methods. First, there seems to be an absence of causal literature on key essential research questions for oral health. Second, the diversity and diffusion of causal inferential methods in the dental literature seem very limited so far. Third, while dental research has widely been promoting the use of directed acyclic graphs (DAGs) to help conceptualize causal thinking, comparably little attention seems to have been paid to choosing and applying appropriate data-analytic approaches for causal inference. Fourth, similar to other fields of medicine, confusion seems to persist within the dental research community as to the use of causal language. If dental research is to secure a robust evidence base for promoting effective oral health interventions, we argue that dental research needs to move beyond its current methodological echo chamber and embrace a radically different approach to causal inference. We call for editors, reviewers, and authors to embrace a much more critically reflective approach to causal inference.

Edentulism is associated with increased risk of all-cause mortality in adult men

BACKGROUND

Prior reports of positive associations between edentulism and all-cause mortality have been limited by onetime assessments of edentulism and inadequate control of known confounding variables. The authors aimed to assess the association between edentulism and mortality using a longitudinal clinical oral health cohort.

METHODS

The authors used data from the Department of Veterans Affairs Dental Longitudinal Study, an ongoing, closed-panel cohort study from 1968 through 2019 (N = 1,229). Dentition status was evaluated through triennial clinical examinations. Mortality was assessed via the National Death Registry. The authors used Cox regression models to estimate the association between edentulism and all-cause mortality after covariate adjustment. Furthermore, the authors calculated propensity scores and assessed hazard ratios (HRs) in a trimmed, matched, and inverse probability weighted sample.

RESULTS

Participants who were edentulous (N = 112) had 1.24 (95% CI, 1.00 to 1.55) times the hazard of all-cause mortality compared with those who were nonedentulous, after adjustment with time-varying covariates. Use of propensity scores in the model resulted in slightly elevated HRs compared with the standard Cox model, regardless of propensity score method; adjusted HRs were 1.35 (95% CI, 1.01 to 1.80) after matching, 1.26 (95% CI, 1.00 to 1.59) after trimming, and 1.29 (95% CI, 1.18 to 1.42) after inverse probability weighting.

CONCLUSIONS

Edentulism was associated with an increased risk of all-cause mortality in a cohort that captured incident edentulism. This association was consistent after multiple methods to account for confounding.

PRACTICAL IMPLICATIONS

The findings of this study suggest that edentulism is associated with an increase in risk of mortality, after accounting for salient confounding variables using multiple approaches. Efforts to improve equitable access to tooth-preserving treatments are critical.

Using dagR to identify minimal sufficient adjustment sets and to simulate data based on directed acyclic graphs

Motivation

Directed acyclic graphs (DAGs) are causal diagrams that can be used to identify confounding or selection bias in observational studies, and are increasingly used in many areas of medical research. In the add-on package dagR for the statistical software R, a set of simple graphical rules was implemented to identify minimal sufficient adjustment sets or harmful adjustment.

General features

The dagR package allows an automated approach for realistic causal structures featuring numerous variables and dependencies, where a manual approach may be too tedious and error-prone. The algorithmic adherence to the graphical step-by-step approach often used in DAG theory introductory courses, together with functionalities for plotting and simulating data conforming to the causal structure of an arbitrary DAG, renders the dagR package particularly useful for both teaching purposes and methodological research.

Availability

dagR is available under the GNU general public licence (GPL-2) from within R or by download at [https://CRAN-R-project.org/package=dagR].

Association between dry mouth and physical frailty among community-dwelling older adults in Japan: The Otassha Study

OBJECTIVE

To elucidate the relationship between physical frailty and dry mouth among community-dwelling older adults in Japan.

BACKGROUND

Oral hypofunction is associated with physical frailty in older adults. Dry mouth, subjectively evaluated as xerostomia and objectively measured as hyposalivation, is highly prevalent in older adults. However, few reports have used both measures of dry mouth and investigated their association with physical frailty.

MATERIALS AND METHODS

This cross-sectional study included 643 individuals (mean age, 73.9 years) from the Otassha Study in 2019. Xerostomia was assessed using the 5-item Summated Xerostomia Inventory (SXI). Hyposalivation was assessed by measuring the amount of resting saliva using the modified cotton roll method. Frailty phenotypes were defined by weakness, slowness, weight loss, low physical activity level and exhaustion components, and served as the outcome variable. Participants with three or more components were considered physically frail, and those with one or two components were considered pre-frail. Ordinal logistic regression analyses were performed to evaluate the associations between physical frailty and xerostomia and hyposalivation.

RESULTS

Among the participants, 4.5% and 49.8% had physical frailty and pre-frailty, respectively. In ordinal logistic regression analysis adjusted for demographic and health characteristics, the SXI score was associated with physical frailty status (adjusted odds ratio for a one-point increase in SXI, 1.12; 95% confidence interval, 1.06-1.19). However, no difference was observed between the amount of resting saliva and severity of physical frailty.

CONCLUSION

Xerostomia is associated with physical frailty among community-dwelling older adults in Japan.

CLINICAL TRIAL REGISTRATION

Not applicable.

Hydrogeogenic fluoride in groundwater and dental fluorosis in Thai agrarian communities: a prevalence survey and case-control study

Background

Dental fluorosis can be a disease of social inequity in access to safe drinking water. This dental public health issue becomes prominent in socially disadvantaged agrarian communities in fluoride endemic areas where the standard irrigation system is unavailable and groundwater containing natural fluoride is the major drinking water source. This study aimed to determine the prevalence and severity of dental fluorosis in children and to evaluate its association with fluoride in groundwater in the aforementioned setting in Thailand.

Methods

A cross-sectional survey of 289 children in Nakhon Pathom Province was conducted in 2015. Children with very mild to severe fluorosis were regarded as ‘cases’ while their counterparts were ‘controls’ for a subsequent case–control study. Records of fluoride concentrations in groundwater used for household supply corresponding to resident and number of years by age of each child during 2008–2015 were retrieved. Other exposure variables were measured using a questionnaire. Prevalence ratio (PR), a measure indicating the relative effect of different levels of fluoride on dental fluorosis, was obtained from Poisson regression with robust standard error.

Result

There were 157 children with very mild to moderate dental fluorosis (54.3% prevalence). The univariable analysis revealed that the prevalence of dental fluorosis among children with fluoride concentrations in water sources of 0.7–1.49 (index category 1) and ≥ 1.5 ppm (index category 2) was 1.62 (95% CI; 0.78, 3.34) and 2.75 (95% CI; 1.42, 5.31) times the prevalence among those with fluoride < 0.7 ppm (referent category). After adjusting for all covariates, the adjusted prevalence ratios in both index categories were 1.64 (95% CI; 0.24, 11.24) and 2.85 (95% CI; 0.44, 18.52) which were close to their corresponding crude estimates. Since the magnitude of confounding, measured by (PR_crude–PR_adjusted)/PR_adjusted, were less than 10% for both index categories; this indicated the limited confounding effect of all covariates.

Conclusions

In fluoride endemic areas, groundwater containing natural fluoride utilized for household consumption resulted in high dental fluorosis prevalence, particularly in the groundwater with fluoride concentrations of ≥ 1.5 ppm.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01902-8.

Sleep duration and severe periodontitis in middle-aged Japanese workers

AIM

To evaluate the association between sleep duration and severe periodontitis in Japanese workers.

MATERIALS AND METHODS

This cross-sectional study included 1130 workers (mean age 43.0 years) who underwent full-mouth periodontal examinations and health check-ups and completed a self-administered questionnaire that included questions on sleep duration. Logistic regression and a restricted cubic spline model were used to analyse the data.

RESULTS

Severe periodontitis was identified in 6.3% of the study population. Those with <5, 5-5.9, 6-6.9, 7-7.9, and ≥8 hr of sleep were 6.7%, 17.4%, 40.3%, 26.3%, and 8.9%, respectively. After adjusting for potential confounders, study participants who slept <5 hr were more likely to have severe periodontitis (adjusted odds ratio = 2.64; 95% confidence interval = 1.06-6.60) than those who slept 7-7.9 hr. The spline model, with a reference value of 399 min (the median sleep duration), showed a non-linear association between sleep duration and severe periodontitis, where an increased prevalence of severe periodontitis was observed only among those with a shorter sleep duration. The prevalence of severe periodontitis did not increase with longer sleep duration.

CONCLUSIONS

Short sleep duration was associated with severe periodontitis in this cohort of Japanese adults.

Access to oral health care services for individuals with rare genetic diseases affecting skeletal development

OBJECTIVE

To identify factors associated with oral health care services for individuals with and without rare genetic diseases.

MATERIALS AND METHOD

A cross-sectional study was undertaken, with 140 individuals paired by sex and age (70 with rare genetic diseases and 70 without), aged between 3 and 27 years, and their parents. The sample was selected from two reference hospitals for patients with rare genetic diseases in southeastern Brazil. The parents completed a questionnaire on individual aspects and their child's medical/dental history. Participants who did and did not suffer from rare genetic diseases were examined for dental caries, malocclusion, dental anomalies, and oral hygiene. The theoretical model Directed Acyclic Graphs (DAG) was used to identify possible confounding variables in the association between rare diseases and access to dental care. Descriptive analyses and non-matched and matched logistic regression models (p < 0.05) were carried out.

RESULTS

The chance of individuals without rare genetic disease having access to oral health care service was 5.32 times higher (95% CI 2.35-12.01) than those with such conditions. Individuals who had not suffered upper respiratory tract infections had a 3.16 times greater chance of being in the group with access to oral health care service (95% CI 1.45-6.90).

CONCLUSION

Individuals with no rare genetic diseases and no history of upper respiratory tract infections had a greater chance of belonging to the group of individuals with access to a dental service. Individuals with rare genetic diseases have less access to oral health care.

Investigation of direct and indirect association of ultra-processed food intake and periodontitis

BACKGROUND

Ultra-processed foods are associated with both sugar intake and non-communicable diseases. We aimed to assess whether the intake of ultra-processed food is associated with periodontal disease and whether this association, if present, is dependent on non-communicable diseases.

METHODS

This analysis used data from cycles 2009 to 2010, 2011 to 2012, and 2013 to 2014 of the National Health and Nutrition Examination Survey (NHANES), including participants aged 30 years or older. Dietary recalls were categorized according to the NOVA classification, and total contribution of ultra-processed foods to daily energy intake (%E) was calculated. Cases of periodontitis were defined as moderate or severe according to the CDC working group criteria for use in population surveillance of periodontitis. Adjustment variables to estimate total and direct associations were defined with directed acyclic graphs. Odds ratios were estimated with logistic regression for moderate/severe periodontitis and severe periodontitis, and ordinal logistic regression for the trichotomized outcome. Analyses were performed using NHANES fasting subsample weights.

RESULTS

Sample participants numbered 4809 (52.2% female), with a mean age of 52.1 years (SE, 0.3). The prevalence of periodontal disease was 27.8% for moderate and 6.5% for severe cases. Mean %E from ultra-processed foods was 54.4 (SE, 0.5). No significant crude, direct, or total association between ultra-processed %E and periodontal disease was found.

CONCLUSION

Intake of ultra-processed foods is not associated with periodontal disease in US non-institutionalized adults over 30 years old, whether directly or by mediation.

Oral hypofunction and malnutrition among community-dwelling older adults: Evidence from the Otassha study

OBJECTIVE

This study investigated the association between oral hypofunction and malnutrition among community-dwelling older adults.

BACKGROUND

Oral hypofunction, a 7-component phenotype of the clinical features of oral health, has been described in Japan. Data about its association with nutritional status are limited.

MATERIALS AND METHODS

This cross-sectional study enrolled 715 adults (mean age, 73.5 years; range, 65-91 years) from the Otassha Study. Oral hypofunction was defined as the presence of ≥3 of the following 7 components: poor oral hygiene; oral dryness; low occlusal force; low articulatory oral motor skill; low tongue pressure; low masticatory performance; and compromised swallowing function. The Mini Nutritional Assessment^® -Short Form (MNA^® -SF) was used to assess the nutritional status. Malnutrition was defined as having an MNA^® -SF score of seven or less. The association between oral hypofunction and nutritional status was evaluated using ordinal logistic regression analyses.

RESULTS

The prevalence rates of oral hypofunction and malnutrition were 42.7% and 4.1%, respectively. Multivariable Poisson regression analyses revealed that oral hypofunction was associated with malnutrition. The adjusted relative risk of malnutrition in the study participants with oral hypofunction was 3.00 with a 95% confidence interval of 1.29-6.98.

CONCLUSION

Community-dwelling older adults whose oral functions were compromised in multiple aspects had poor nutritional status.

Is dietary pattern a mediator of the relationship between socioeconomic status and dental caries?

OBJECTIVE

To investigate whether a healthy diet and added sugar mediate the relationship between socioeconomic status and oral health status in adults.

METHODS

This is a secondary cross-sectional analysis of adult participants from the 2015-2016 National Health and Nutrition Examination Survey from the United States (n=3367). Structural equation modeling tested direct and indirect pathways from a latent variable for socioeconomic status to oral health via healthy eating (Health Eating Index) and added sugar in a multiple-mediator multiple-outcome model.

RESULTS

Added sugar was directly associated with untreated dental caries [Standardized coefficient (SC)=0.10], and healthy eating was directly associated with both untreated dental caries (SC=-0.11) and tooth loss (SC=-0.05). Higher socioeconomic status was associated with lower untreated dental caries through direct (SC =-0.246) and small indirect paths via healthy diet (SC= -0.026), lower consumption of added sugar (SC=-0.007), and dental visits (SC=-0.162). Higher socioeconomic status was associated with fewer teeth lost through direct (SC =-0.306) and very small indirect paths via healthy diet (SC=-0.016), added sugar consumption (SC=-0.001), and untreated dental caries (SC=-0.094).

CONCLUSIONS

Both socioeconomic status and dietary pattern independently contributed to tooth loss and dental caries. The contribution of dietary factors as a mediator to socioeconomic inequities in oral health was small, and statistically significant.

CLINICAL RELEVANCE

A systems approach to socioeconomic inequities in oral health takes into account the complex relationships between socioeconomics, dietary patterns, oral health and health. Socioeconomic conditions and nutrition, as common risk factors to noncommunicable disorders, should be tackled in programs to improve oral health.

Is Continuous Eruption Related to Periodontal Changes? A 16-Year Follow-up

The aims of this study were to 1) determine if continuous eruption occurs in the maxillary teeth, 2) assess the magnitude of the continuous eruption, and 3) evaluate the effects of continuous eruption on the different periodontal parameters by using data from the population-based cohort of the Study of Health in Pomerania (SHIP). The jaw casts of 140 participants from the baseline (SHIP-0) and 16-y follow-up (SHIP-3) were digitized as 3-dimensional models. Robust reference points were set to match the tooth eruption stage at SHIP-0 and SHIP-3. Reference points were set on the occlusal surface of the contralateral premolar and molar teeth, the palatal fossa of an incisor, and the rugae of the hard palate. Reference points were combined to represent 3 virtual occlusal planes. Continuous eruption was measured as the mean height difference between the 3 planes and rugae fix points at SHIP-0 and SHIP-3. Probing depth, clinical attachment levels, gingiva above the cementoenamel junction (gingival height), and number of missing teeth were clinically assessed in the maxilla. Changes in periodontal variables were regressed onto changes in continuous eruption after adjustment for age, sex, number of filled teeth, and education or tooth wear. Continuous tooth eruption >1 mm over the 16 y was found in 4 of 140 adults and averaged to 0.33 mm, equaling 0.021 mm/y. In the total sample, an increase in continuous eruption was significantly associated with decreases in mean gingival height (B = -0.34; 95% CI, -0.65 to -0.03). In a subsample of participants without tooth loss, continuous eruption was negatively associated with PD. This study confirmed that continuous eruption is clearly detectable and may contribute to lower gingival heights in the maxilla.

Does the Trimester of Smoking Matter in the Association between Prenatal Smoking and the Risk of Early Childhood Caries?

INTRODUCTION

Development of the primary tooth bud commences at the end of the 5th week of gestation, with mineralization starting at about the 13th week and continuing throughout pregnancy to the end of the first year of life. During this critical period, exposure to maternal lifestyle factors, specifically, prenatal smoking can negatively affect the quality (i.e., tooth calcification and mineralization) and timing of tooth eruption.

METHODS

This study evaluated the association between the trimester of smoking and offspring caries experience at 3 time points (31, 43, and 61 months) by analyzing data from 1,429 mother-offspring participants in the 1991/92 Avon Longitudinal Study of Parents and Children, conducted in Bristol, England. Prenatal smoking in the first, second, and third trimesters were self-reported during pregnancy while offspring caries experience was determined by clinical oral examinations. Adjusted for confounders, log-binomial regression estimated the risk ratio (RR) and 95% confidence interval (CI) of the association between trimester of smoking and the risk of offspring caries.

RESULTS

Twenty percent smoked in the first trimester of their pregnancy, 15% in the second, and 17% in the third. Forty-six percent of children whose mothers smoked during pregnancy had caries experience (i.e., dmft ≥1) with a mean dmft count of 1.58, versus children whose mothers did not smoke during pregnancy (33% of whom had dmft ≥1 with a mean dmft count of 0.33). Smoking in the first, second, and third trimesters were independently associated with a higher adjusted RR (95% CI) of caries experience at 61 months, i.e., 1.16 (0.93-1.43), 1.11 (0.75-1.65), and 1.60 (1.09-2.32), respectively.

CONCLUSIONS

Within the limitations of covariates adjusted for, with the caveat that residual confounding and bias from unmeasured covariates are likely present, our findings suggest that smoking during pregnancy may be harmful to the oral health of the offspring irrespective of the trimester during which the smoking occurred. Nevertheless, these results should be interpreted cautiously because the findings might not generalize broadly.

A population-based cross-sectional study of the association between periodontitis and arterial stiffness among the older Japanese population

OBJECTIVE

To investigate the potential association between periodontitis and arterial stiffness among the older Japanese population.

BACKGROUND

The prevalence of periodontitis is increasing in Japanese older adults. Arterial stiffness increases the risks of cardiovascular events and death, morbidity, and dementia.

METHODS

This secondary analysis of data from a cross-sectional study evaluated the periodontal inflamed surface area (PISA), reflecting the amount of inflamed periodontal tissue that was estimated by a full-mouth periodontal examination. Severe periodontitis was defined per the parameters provided by the Centers for Disease Control/American Academy of Periodontology. The Cardio-Ankle Vascular Index (CAVI) was used for measuring the overall stiffness of the artery, and higher CAVI indicated increased arterial stiffness. An ordinal logistic regression model was used to evaluate the association between periodontitis and arterial stiffness.

RESULTS

The analysis included 185 Japanese adults [35% men; age, mean (standard deviation) 80.2 (4.4) years]. The average PISA and the prevalence of severe periodontitis were 64.4 mm² and 27.6%, respectively; 54 (29.2%), 56 (30.3%), and 75 (40.5%) participants were stratified to the CAVI < 9, 9 ≤ CAVI <10, and CAVI ≥ 10 groups, respectively. After adjusting for potential confounders, the odds ratio of the prevalence and severity of arterial stiffness evaluated using CAVI was 1.06 [95% confidence interval (CI) 1.01 to 1.10] for PISA per 10 mm² and 2.12 (95% CI 1.09 to 4.11) for severe periodontitis.

CONCLUSION

Periodontitis was associated with arterial stiffness among Japanese older adults. Further studies are needed to investigate whether arterial stiffness is an intermediate factor in the pathway between periodontitis and systemic diseases, including cardiovascular disease and dementia.

A scoping review of Table 2 fallacy in the oral health literature

BACKGROUND

Coined by Westreich and Greenland in 2013, Table 2 fallacy refers to the practice of reporting estimates of the primary exposure and adjustment covariates derived from a single model on the same table. This study seeks to describe the extent to which Table 2 fallacy is present in the oral health literature and provide recommendations on presenting findings from multivariable-adjusted models and/or interpretation of adjustment covariate estimates that are not the primary exposure.

METHODS

We conducted a scoping review in PubMed and Scopus of human observational studies published in 4 oral health journals (JDR-CTR, CDOE, JPHD, BMC Oral Health) starting in 2013 until the end of 2018. The resulting articles were exported into Excel and were either included or excluded for full-text review based on six criteria. After categorizing the articles, we exported and summarized the results in SAS.

RESULTS

A total of 1358 articles were initially screened of which 937 articles were excluded based on title or abstract for being animal studies, systematic reviews or meta-analysis, prediction models or descriptive studies. The remaining 421 articles were eligible for full text reviewed of which, 189 (45%) committed Table 2 fallacy. The prevalence of table 2 fallacy appears high in the oral health literature.

CONCLUSIONS

The problem of presenting multiple effect estimates derived from a single model in the same table is that it inadvertently encourages the reader to interpret all estimates the same way, often as total effects. Implications and recommendations are discussed.

A quantitative bias analysis to assess the impact of unmeasured confounding on associations between diabetes and periodontitis

AIM

To investigate unmeasured confounding in bidirectional associations between periodontitis and diabetes using quantitative bias analysis.

METHODS

Subsamples from the Veterans Affairs Dental Longitudinal Study were selected. Adjusted for known confounders, we used Cox proportional hazards models to estimate associations between pre-existing clinical periodontitis and incident Type II Diabetes (n = 672), and between pre-existing diabetes and incident severe periodontitis (n = 521), respectively. Hypothetical confounders were simulated into the dataset using Bernoulli trials based on pre-specified distributions of confounders within categories of each exposure and outcome. We calculated corrected hazard ratios (HR) over 10,000 bootstrapped samples.

RESULTS

In models using periodontitis as the exposure and incident diabetes as the outcome, adjusted HR = 1.21 (95% CI: 0.64-2.30). Further adjustment for simulated confounders positively associated with periodontitis and diabetes greatly attenuated the association or explained it away entirely (HR = 1). In models using diabetes as the exposure and incident periodontitis as the outcome, adjusted HR = 1.35 (95% CI: 0.79-2.32). After further adjustment for simulated confounders, the lower bound of the simulation interval never reached the null value (HR ≥ 1.03).

CONCLUSIONS

Presence of unmeasured confounding does not explain observed associations between pre-existing diabetes and incident periodontitis. However, presence of weak unmeasured confounding eliminated observed associations between pre-existing periodontitis and incident diabetes. These results clarify the bidirectional periodontitis-diabetes association.

Respiratory symptoms of exposure to substances in the workplace among Bulgarian dentists

OBJECTIVES

Dentists are exposed to a variety of airborne chemicals that can act as irritants and sensitizers and may give rise to work-related respiratory symptoms. The aim of this study was to estimate the prevalence of respiratory symptoms of exposure to substances in the workplace and associated risk factors in Bulgarian dentists.

METHODS

A cross-sectional study was performed among Bulgarian dentists by using a self-report questionnaire. A direct acyclic graph (DAG) was elaborated to illustrate the direct and indirect causal pathways between exposure to irritants and/or allergens from dental environment and work-related respiratory symptoms among dentists. Multiple logistic regression analysis was conducted in order to investigate the relationship between sex, work experience, daily exposure to chemicals from dental environment, history of atopic disorder and work-related respiratory symptoms.

RESULTS

A total of 4675 dentists completed the questionnaire (response rate 48.1%). The prevalence of self-reported work-related respiratory symptoms was 20.7%. The most common repeated causes of respiratory reactions were disinfectants (65.7%) and materials based on acrylic resins (29.7%). Factors associated with work-related respiratory symptoms are personal history of asthma (odds ratio (OR) 2.50, 95% confidence interval [CI]: 1.71-3.64), work experience >20 years (OR 2.17, 95% CI: 1.74-2.70) and female gender (OR 2.14, 95% CI: 1.81-2.56).

CONCLUSION

Work-related respiratory symptoms are frequent among dentists and indicate a need for efforts to establish effective programmes and techniques of reducing or eliminating direct exposure to airborne chemicals in the dental environment.

Prenatal smoking and the risk of early childhood caries: A prospective cohort study

Introduction

Dental caries is a chronic complex disease of multifactorial etiology that affects a quarter of U.S. children. This study evaluated the association between prenatal smoking and offspring caries experience and used a negative control exposure analysis to assess if the association is causal.

Methods

Data from 1429 mother-offspring participants of the 1991/92 Avon Longitudinal Study of Parents and Children conducted in Bristol, England were analyzed. Prenatal smoking (yes v. no) and quantity smoked (none, <half pack, ≥half pack) were self-reported while offspring caries experience was determined by clinical oral examinations at 3 time points. Discrete time hazards regression estimated hazard odds of first occurrence of offspring caries, and substituted partner smoking for prenatal smoking in a negative control exposure analysis.

Results

Overall, 22% smoked during pregnancy while 36% of partners smoked. The adjusted hazard odds of first occurrence of caries experience in the offsprings of prenatal smokers compared to the offsprings of non-smokers was 1.42 (95% CI: 1.08, 1.86). Relative to non-smoking, smoking <half pack/day and ≥half pack/day during pregnancy were associated with higher adjusted hazard odds of offspring caries experience: 1.10 (95% CI: 0.79, 1.54) and 1.38 (0.98, 1.95) respectively. Partner smoking was associated with 33% (95% CI: 1.07, 1.65) higher adjusted hazard odds of first offspring caries experience occurrence.

Conclusions

Prenatal and partner smoking appear associated with greater offspring caries experience. The positive association with partner smoking suggests either a shared genetic predisposition or unmeasured common environmental factors with the mother as opposed to a direct biological effect of the intrauterine environment.

Causal inference and directed acyclic graph: An epidemiological concept much needed for oral submucous fibrosis

Oral submucous fibrosis (OSMF), although already established as an oral potentially malignant disorder (OPMD), still stands over a weak bridge because of its controversial pathogenesis. There has been tremendous work on this disease since 1962, surprisingly, we are unsuccessful in finding the exact causation of OSMF. The potential cause for this is either a lack of systematically performed clinical observational studies or over-interpreted inferences of the presented results. Accordingly, the literature is piled with complex data that is being followed by emerging researchers. Hence, this conceptual paper is presented to focus and explain only the epidemiological concepts of causal inference and the construction of DAGs. These concepts will help to encode our subject matter knowledge and assumptions regarding the causal structure problem, classify the source of systematic bias, identify the potential confounders, potential issues in the study design, and guide the data analysis.

Interdental Cleaning and Oral Health Status in an Adult Cohort, 2015 to 2018

Interdental cleaning is routinely recommended, despite limited evidence supporting efficacy to prevent advanced oral disease endpoints, such as caries and periodontal disease. We aimed to examine associations between interdental cleaning and oral health in a large, generalizable prospective cohort of adults in the United States. Data were drawn from wave 3 (2015 to 2016, n = 26,086 included in analysis) and wave 4 (2016 to 2018, n = 22,585) of the adult component (age ≥18 y) of the nationally representative Population Assessment of Tobacco and Health Study. Survey-weighted multivariable regression models estimated the associations between wave 3 weekly interdental cleaning frequency and 6 measures of self-reported oral health-overall rating, tooth extractions, gum bleeding, loose teeth, bone loss around teeth, and gum disease-cross-sectionally and prospectively, with adjustment for established periodontal disease risk factors. As compared with no interdental cleaning, interdental cleaning ≥7 times/wk was prospectively associated with greater odds of excellent self-rated oral health (adjusted odds ratio, 1.37; 95% CI, 1.17 to 1.62), lower odds of bleeding gums (adjusted odds ratio, 0.62; 95% CI, 0.54 to 0.70), but not statistically significantly lower odds of other oral health conditions in the following 12 mo. Older age, lower socioeconomic status, diabetes, and cigarette smoking were consistently associated with worse oral health across all outcome measures. Findings were largely robust to alternative model and variable specifications. Interdental cleaning is associated with better perceived oral health and less self-reported gingivitis. Prevention of more advanced disease states was not demonstrated. These findings should be interpreted cautiously given the self-reported nature of the measures and relatively short follow-up period.

A Causative Approach to Demographic and Socioeconomic Factors Affecting Parental Ratings of Child Oral Health

INTRODUCTION

Many studies have investigated associations between demographic, socioeconomic status (SES), behavioral, and clinical factors and parental ratings of child oral health. Caries experience, pain, missing teeth, malocclusions, and conditions and treatments likely to negatively affect the child or family in the future have been consistently associated with poorer parental ratings. In contrast, effect sizes for associations between demographic and SES indicators (race/ethnicity, country of birth, family structure, household income, employment status, and parental education levels) and parental ratings vary greatly.

OBJECTIVES

The primary objectives of this study were to estimate effect sizes for associations between demographic and SES variables and parental ratings of child oral health and then to consider possible causal implications.

METHODS

This article uses a nationally representative data set from 24,664 Australian children aged 5 to 14 y, regression analyses guided by a directed acyclic graph causal model, and sensitivity analyses to investigate effects of demographic and SES factors on parental ratings of oral health.

RESULTS

One in 8 children had oral health rated as fair or poor by a parent. Indigenous children, older boys, young children with a migrant parent, children from single-parent families, low-income households and families where no parent worked full-time, and children whose parents had lower education levels were much more likely to receive a fair or poor parental oral health rating in crude and adjusted models.

CONCLUSION

This cross-sectional study helps to clarify inconsistent findings from previous research and shows many demographic and SES variables to be strong determinants of parental ratings of child oral health, consistent with the effects of these variables on other health outcomes. Sensitivity analyses and consideration of the potential for chance and bias to have affected these findings suggest that many of these associations may be causal.

KNOWLEDGE TRANSFER STATEMENT

Based on regression analyses driven by a directed acyclic graph causal model, this research shows a strong impact of demographic and socioeconomic determinants on parental ratings of child oral health, consistent with associations between these variables and other oral and general health outcomes. Many of these associations may be causal. We demonstrate the value of causal models and causal thinking when analyzing complex multilevel observational data.

Association of maternal HIV-1 severity with dental caries: an observational study of uninfected 5- to 7-yr-old children of HIV-1-infected mothers without severe immune suppression

Treatment programs to prevent perinatal and postnatal HIV-1 transmission have become available in sub-Saharan Africa, leading to an emerging population of HIV-1 exposed uninfected (HEU) children. Exposure to HIV-1 in utero and during breastfeeding may increase the risk of morbidity and mortality in HEU children. This study estimated the association of the severity of maternal HIV-1 infection as assessed by CD4 count and viral load at baseline (7 d postpartum), with  dmft count of their 5- to 7-yr-old HEU offspring. A follow-up study was conducted of HIV-1-infected mother-HEU children pairs (n = 164) from the Ugandan site of the ANRS 12341-PROMISE- PEP trial (ClinicalTrials.gov, number NCT00640263). HIV-1-infected mothers were interviewed and the HEU children were examined for caries using the World Health Organization's survey methods for field conditions and the dmft index. Directed acyclic graphs and negative binomial regression were used for analyses. The prevalence of 1 or more dmft was 48%. Negative binomial regression showed no association between the dmft count and maternal CD4 counts 7 d postpartum but a 10% lower dmft count with longer breastfeeding duration was found. Maternal CD4 count at birth was not associated with the dental caries experience in uninfected children born to women without severe immune suppression, while there appeared to be a protective effect of high viral load and breastfeeding duration.

Self-Weighted Multi-Kernel Multi-Label Learning for Potential miRNA-Disease Association Prediction

Researchers have realized that microRNAs (miRNAs) play significant roles in the pathogenesis of various diseases. Although many computational models have been proposed to predict the associations between miRNAs and diseases, prediction performance could still be improved. In this paper, we propose a novel self-weighted, multi-kernel, multi-label learning (SwMKML) method to predict disease-related miRNAs. SwMKML adaptively learns two optimal kernel matrices for both miRNAs and diseases from multiple kernels constructed from known miRNA-disease associations. Moreover, the miRNA-disease associations predicted from both spaces are updated simultaneously based on a multi-label framework. Compared with four state-of-the-art computational models, SwMKML achieved best results of 95.5%, 93.1%, and 84.1% in global leave-one-out cross-validation, 5-fold cross-validation, and overall prediction accuracy, respectively. A case study conducted on head and neck neoplasms further identified two potential prognostic biomarkers, hsa-mir-125b-1 and hsa-mir-125b-2, for the disease. SwMKML is freely available at Github, and we anticipate that it may become an effective tool for potential miRNA-disease association prediction.

Assessing a possible vulnerability to dental caries in individuals with rare genetic diseases that affect the skeletal development

Background

Individuals diagnosed with a rare genetic disease that affects skeletal development often have physical limitations and orofacial problems that exert an impact on oral health. The aim of the present study was to analyze the possible vulnerability to dental caries in individuals with rare genetic diseases that affect skeletal development.

Methods

A paired cross-sectional study was carried out with a sample of 140 individuals [70 with rare genetic diseases affecting skeletal development: mucopolysaccharidosis (MPS) (n = 29) and osteogenesis imperfecta (OI) (n = 41) and 70 without rare diseases] and their parents/caregivers. The participants in the first group were recruited from two reference hospitals specialized in rare genetic diseases in the city of Belo Horizonte, Brazil. All participants were examined for the evaluation of breathing type, malocclusion, dental anomalies, oral hygiene and dental caries. The parents/caregivers answered a structured questionnaire addressing the individual/behavioral characteristics and medical/dental history of the participants. Statistical analysis involved the chi-square test and multiple logistic regression analysis for the dependent variable (dental caries) (α = 5%). This study received approval from the Human Research Ethics Committee of the Universidade Federal de Minas Gerais.

Results

The mean age of the individuals was 10.34 ± 6.55 years (median: 9.50 years). Individuals with inadequate oral hygiene were 4.70–fold more likely to have dental caries (95% CI: 2.13–10.40) and those with the rare genetic diseases (MPS/OI) were 2.92-fold more likely to have dental caries (95% CI: 1.38–6.17).

Conclusion

Individuals with inadequate oral hygiene and those with MPS and OI had a greater chance of belonging to the group with dental caries. Based on the present findings, individuals with the rare genetic diseases may be considered vulnerable to caries.

Structure and Control of Healthy Worker Effects in Studies of Pregnancy Outcomes

Much of the literature on the healthy worker effect focuses on studies of chronic disease and mortality; however, when studying pregnancy outcomes, these effects might differ because of the short, defined risk periods of most pregnancy outcomes. Three pregnancy-specific healthy worker effects have also been described, but the structure of these effects has not yet been investigated when occupational exposure, and not employment status, is the exposure of interest. We used directed acyclic graphs to examine healthy worker effects in studies of occupational exposures and pregnancy outcomes: the healthy hire effect, the healthy worker survivor effect, the desperation/privilege effect (differential workforce reentry after pregnancy), the reproductively unhealthy worker effect (women with live births leave the workforce, while women with nonlive births do not), and the insecure pregnancy effect (women with adverse pregnancy outcomes reduce their exposures in subsequent pregnancies). Given our assumptions, we conclude that the healthy hire effect, the desperation/privilege effect, the reproductively unhealthy worker effect, and the insecure pregnancy effect result from confounding that can be addressed if data on measured confounders, such as employment status, are available. The presence of the healthy worker survivor effect, however, varies by study design. Different types of healthy worker effects can be present in studies of occupational exposure and pregnancy outcomes, and many of them are easily addressed analytically.

Does periodontitis affect diabetes incidence and haemoglobin A1c change? An 11-year follow-up study

AIM

As periodontitis may contribute to the pathogenesis of diabetes, the effects of periodontitis on diabetes incidence and HbA1c change was quantified in a prospective cohort.

METHODS

Data from an 11-year follow-up of the Study of Health in Pomerania were analyzed to evaluate the effects of periodontitis on incident diabetes and long-term HbA1c changes in 2047 subjects aged 20-81years. Diabetes was based on self-reported physician diagnoses, antidiabetic medication use, or HbA1c≥6.5% or non-fasting blood glucose levels ≥11.1mmol/L. To assess periodontal status, periodontal pockets were probed, and their depth and clinical attachment levels measured. For both measures, means and percentages of sites≥3mm were calculated. In addition, all probing depths≥4mm were summed (cumulative probing depth). Modified Poisson and multivariable linear models were applied, adjusted for age, gender, highest level of general education, marital status, waist circumference, physical activity, smoking status and follow-up time.

RESULTS

Over a mean follow-up period of 11.1years, 207 subjects developed diabetes. Baseline mean clinical attachment levels (CAL) and probing depths (PPD) were not significantly associated with either diabetes incidence [mean CALs, fourth quartile, incidence rate ratio=0.819, 95% confidence interval (CI): 0.489-1.370; P=0.446] or long-term changes in HbA1c (mean CAL, fourth quartile, β=-0.086, 95% CI: -0.187, -0.016; P=0.098). Sensitivity analyses using alternative exposure definitions confirmed these results.

CONCLUSION

Contrary to the currently available literature, no convincing evidence was found of any potential association between periodontitis and diabetes incidence or HbA1c change.

Breastfeeding and Oral Health: Evidence and Methodological Challenges

Breastfeeding is a powerful health-promoting behavior. A 2016 Lancet global collaboration to review the health implications of breastfeeding was among the first to consider oral health outcomes. While a role was suggested for breastfeeding in preventing malocclusion, caries was the only included disease condition unfavorably associated with breastfeeding. The present critical review examines the evidence connecting breastfeeding practices to these outcomes and discusses the methodological challenges inherent in reaching causal conclusions. Published systematic reviews show some evidence of a protective effect of breastfeeding against primary dentition malocclusion but no supportive evidence for mixed dentition and permanent dentition malocclusions. Regarding caries, well-conducted studies report a benefit with breastfeeding up to 12 mo but a positive association between caries and breastfeeding of longer duration, at times that vary between 12 and 24 mo, as well as nocturnal feeding. Future studies would be methodologically stronger if focused on specific malocclusion traits that are plausibly associated with sucking movements rather than using general malocclusion indices. Studies should use detailed and consistent terminology for breastfeeding definition, including frequency, intensity, and timing. Analytical studies should be carried out to distinguish between confounders (e.g., prematurity) and mediators (e.g., use of pacifier). Regarding a link to caries, standard terminology for exposures (e.g., nocturnal feeding) is recommended. Statistical analyses must account for known confounding factors (e.g., socioeconomic conditions) but avoid inappropriate adjustment for variables on a causal path between exposure and outcome or for variables not associated with breastfeeding (e.g., tooth brushing), as can be guided using tools such as direct acyclic graphs. For dental practice, the potential caries risk of long-duration breastfeeding should be part of individual patient counseling that incorporates patient values and circumstances. Given the unquestioned overall health benefits of breastfeeding, the dental community should support World Health Organization guidelines that encourage and promote breastfeeding.

Normative prosthodontic care need: does it impact the daily life of young Saudis with high level of oral diseases? A cross sectional study

BACKGROUND

Assessing the need for prosthodontic care previously included older age groups. There is less information about younger populations who may need this care because of high disease levels. The aim of this study was to assess the normative need for prosthodontic care in a young Saudi population with high oral disease levels, the associated factors and its impact on daily life.

METHODS

A cross sectional study included Saudi adults in the Eastern Province in 2016. A questionnaire was used to assess personal background (confounders), risk factors affecting oral diseases (exposures) and the impact of oral problems on daily life. A clinical examination assessed tooth loss, the presence of prosthodontic appliances, the presence of untreated decay and need for periodontal care. Directed acyclic graphs identified the confounders to be included in regression models with separate outcomes: normative need for prosthodontic care (binary logistic model) and impact on 6 daily life aspects (ordinal regression models).

RESULTS

Complete data were available for 574/ 700 = 82% and 46.7% needed prosthodontic care with 2 lost teeth on average among adults of mean age = 33.2 years. The confounders controlled for the need for prosthodontic care included socioeconomic status (SES), dental visits last year and health insurance. The confounders for the impact on daily life included age and SES. In adjusted models, normative need for prosthodontic care was significantly associated with untreated decay (OR = 2.09, 95% C.I. = 1.37, 3.19). The impact on daily life was not significantly associated with prosthodontic care need but with untreated decay, especially sleeplessness (regression coefficient = 0.53, 95% C.I. = 0.02, 1.04) and dropping daily activities (regression coefficient = 0.79, 95% C.I. = 0.13, 1.46). In addition, the need for periodontal care was associated with food avoidance (regression coefficient = 0.73, 95% C.I. = 0.28, 1.18).

CONCLUSIONS

In Saudi adults in the Eastern Province, there was a considerable normative need for prosthodontic care due to untreated decay. The impact on daily life was related to the underlying oral diseases rather than the need for prosthodontic care itself.

Estimating effects of craniofacial morphology on gingival recession and clinical attachment loss

OBJECTIVES

Evidence on possible associations between facial morphology, attachment loss and gingival recession is lacking. We analysed whether the facial type, which can be described by the ratio of facial width and length (facial index), is related to periodontal loss of attachment, hypothesizing that a broad face might be associated with less gingival recession (GR) and less clinical attachment loss (CAL) than a long face.

MATERIALS AND METHODS

Data from the 11-year follow-up of the population-based Study of Health in Pomerania were used. Periodontal loss of attachment was assessed by GR and CAL. Linear regression models, adjusted for age and gender, were used to assess associations between specific landmark based distances extracted from magnetic resonance imaging head scans and clinically assessed GR or CAL (N = 556).

RESULTS

Analysing all teeth, a higher maximum cranial width was associated with a lower mean GR (B = -0.016, 95% CI: -0.030; -0.003, p = 0.02) and a lower mean CAL (B = -0.023, 95% CI: -0.040; -0.005, p = 0.01). Moreover, a long narrow face was significantly associated with increased mean GR and CAL (facial index, P for trend = 0.02 and p = 0.01, respectively). Observed associations were more pronounced for incisors and canines than for premolars and molars.

CONCLUSION

This study revealed craniofacial morphology, specifically the cranial width and the facial index, as a putative risk factor for periodontal loss of attachment.