Investigating the impact of oral health on pregnancy and offspring outcomes: protocol for the Lifetime Impact of ORal heAlth (LIORA) cohort study.

INTRODUCTION: Oral health is a fundamental component of well-being, and is closely associated with overall health and quality of life. Oral health may also affect the next generation. The children of mothers with poor oral health are likely to also have poor oral health as they go through life. We aim to investigate associations between maternal oral health and general health, pregnancy outcomes, offspring oral health and offspring general health. METHODS AND ANALYSIS: The Lifetime Impact of Oral Health study is a prospective, observational cohort study being done at a single centre in Chongqing, China. A total of 1000 pregnant women will be recruited in their first trimester (11-14 weeks gestation). After obtaining informed consent, general and oral health assessments will be undertaken. Maternal lifestyle, demographic data and biospecimens (blood, hair, urine, nail clippings, saliva, dental plaque, buccal, vaginal and anal swabs) will be collected. Pregnancy outcomes will be recorded at the time of delivery. Cord blood and placenta samples will be collected. The offspring will be followed up for general and oral health examinations, neurodevelopmental assessments and biospecimen (dental plaque, saliva, buccal swabs, exfoliated primary dentition, urine, hair, nail clippings) collection until they are 15 years old. Biological samples will undergo comprehensive metabolomic, microbiome and epigenome analyses. Associations between maternal oral health and general health, pregnancy outcomes, offspring oral health and offspring general health will be investigated and the underlying mechanisms explored. ETHICS AND DISSEMINATION: This project has been approved by the Research Ethics Committee of the Affiliated Hospital of Stomatology of Chongqing Medical University (CQHS-REC-2021 LSNo.23). Participants will be required to provide informed consent to participate in the study. Dissemination of findings will take the form of publications in peer-reviewed journals and presentations at national and international conferences. TRIAL REGISTRATION NUMBER: ChiCTR2100046898.

Differential network analysis of oral microbiome metatranscriptomes identifies community scale metabolic restructuring in dental caries.

Dental caries is a microbial disease and the most common chronic health condition, affecting nearly 3.5 billion people worldwide. In this study, we used a multiomics approach to characterize the supragingival plaque microbiome of 91 Australian children, generating 658 bacterial and 189 viral metagenome-assembled genomes with transcriptional profiling and gene-expression network analysis. We developed a reproducible pipeline for clustering sample-specific genomes to integrate metagenomics and metatranscriptomics analyses regardless of biosample overlap. We introduce novel feature engineering and compositionally-aware ensemble network frameworks while demonstrating their utility for investigating regime shifts associated with caries dysbiosis. These methods can be applied when differential abundance modeling does not capture statistical enrichments or the results from such analysis are not adequate for providing deeper insight into disease. We identified which organisms and metabolic pathways were central in a coexpression network as well as how these networks were rewired between caries and caries-free phenotypes. Our findings provide evidence of a core bacterial microbiome that was transcriptionally active in the supragingival plaque of all participants regardless of phenotype, but also show highly diagnostic changes in the ways that organisms interact. Specifically, many organisms exhibit high connectedness with central carbon metabolism to Cardiobacterium and this shift serves a bridge between phenotypes. Our evidence supports the hypothesis that caries is a multifactorial ecological disease.

Perinatal outcomes and offspring growth profiles in twin pregnancies complicated by gestational diabetes mellitus: A longitudinal cohort study.

AIMS: To evaluate the influence of gestational diabetes mellitus (GDM) on the perinatal outcomes of twin pregnancies and its impact on fetal growth profiles of twin offspring from 6 weeks to 12 months of corrected age. METHODS: A longitudinal cohort study was conducted among pregnant women with twins and their twin offspring. All information on perinatal outcomes and child growth trajectories from 6 weeks to 12 months of corrected age were obtained and analyzed using a general linear model and logistic regression models. RESULTS: GDM was not correlated with adverse perinatal outcomes of twin pregnancies; however, in monochorionic diamniotic (MCDA), but not dichorionic diamniotic (DCDA) twin pregnancies, GDM was correlated with gestational hypertension disorder and a fetus being small for gestational age (OR, 2.68; 95% CI 1.16-6.04 and OR, 0.35; 95% CI 0.16-0.76, respectively). In both MCDA and DCDA groups, GDM was positively associated with a higher risk of childhood overweight at 6 months of corrected age (2.32 [1.05, 5.09] and 2.00 [1.13, 3.53]). CONCLUSIONS: GDM had a greater impact on MCDA twin pregnancies in terms of maternal gestational hypertension disease and small for gestational age of newborns. Additionally, twin offspring exposed to GDM had a higher risk of being overweight at 6 months of corrected age irrespective of chorionicity. CLINICAL TRIAL REGISTRATION: ChiCTR-OOC-16008203.

Longitudinal Study of Oral Microbiome Variation in Twins.

Humans are host to a multitude of microorganisms that rapidly populate the body at birth, subject to a complex interplay that is dependent on host genetics, lifestyle, and environment. The host-associated microbiome, including the oral microbiome, presents itself in a complex ecosystem important to health and disease. As the most common chronic disease globally, dental caries is induced by host-microbial dysbiosis in children and adults. Multiple biological and environmental factors are likely to impact disease predisposition, onset, progression, and severity, yet longitudinal studies able to capture these influences are missing. To investigate how host genetics and environment influenced the oral microbial communities over time, we profiled supragingival plaque microbiomes of dizygotic and monozygotic twins during 3 visits over 12-months. Dental plaque DNA samples were amplified by targeting the 16S rRNA gene V4 region, and microbial findings were correlated with clinical, diet and genetic metadata. We observed that the oral microbiome variances were shaped primarily by the environment when compared to host genetics. Among the environmental factors shaping microbial changes of our subjects, significant metadata included age of the subject, and the age by which subjects initiated brushing habits, and the types of actions post-brushing. Relevant heritability of the microbiome included Actinomyces and Capnocytophaga in monozygotic twins and Kingella in dizygotic twins. Corynebacterium and Veillonella abundances were associated with age, whereas Aggregatibacter was associated with younger subjects. Streptococcus abundance showed an inverse association over time, and Selenomonas abundances increased with brushing frequency per day. Unraveling the exact biological mechanisms in caries has the potential to reveal novel host-microbial biomarkers, pathways, and targets important to effective preventive measures, and early disease control in children.

Genetic and Early-Life Environmental Influences on Dental Caries Risk: A Twin Study.

OBJECTIVES: To explore the relative contributions of genetic and environmental influences on dental caries risk and to investigate fetal and developmental risk factors for dental caries. METHODS: We recruited children from 250 twin pregnancies midgestation and collected demographic, health, and phenotypic data at recruitment, 24 and 36 weeks' gestational age, birth and 18 months, and 6 years of age. 25-hydroxyvitamin D was quantified in mothers at 28 weeks' gestation and in infants at birth. Dental caries and enamel defects were measured at six years of age. We compared concordance for the presence of any caries and advanced caries in monozygotic and dizygotic twin pairs. To investigate environmental risk factors for caries, we fitted multiple logistic regression models using generalized estimating equations to adjust for twin correlation. RESULTS: A total of 345 twins underwent dental assessment, with 111 (32.2%) showing signs of any caries and 83 (24.1%) having advanced caries. There was no evidence of higher concordance in monozygotic twins compared with dizygotic twins, with a difference of 0.05 (95% confidence interval -0.14 to 0.25; P = .30) and 0.00 (95% confidence interval -0.26 to 0.26; P = .50) for any caries and advanced caries, respectively, suggesting that environmental factors, rather than genetics, are the predominant determinant of caries risk. After adjusting for potential confounders, lack of community water fluoridation, hypomineralized second primary molars, dichorionic placenta, and maternal obesity were associated with caries. CONCLUSIONS: Environmental rather than genetic factors drive dental caries risk and arise as early as prenatal life.

Epigenetic Influences on Neurodevelopment at 11 Years of Age: Protocol for the Longitudinal Peri/Postnatal Epigenetic Twins Study at 11 Years of Age (PETS@11).

Neurodevelopment is sensitive to genetic and pre/postnatal environmental influences. These effects are likely mediated by epigenetic factors, yet current knowledge is limited. Longitudinal twin studies can delineate the link between genetic and environmental factors, epigenetic state at birth and neurodevelopment later in childhood. Building upon our study of the Peri/postnatal Epigenetic Twin Study (PETS) from gestation to 6 years of age, here we describe the PETS 11-year follow-up in which we will use neuroimaging and cognitive testing to examine the relationship between early-life environment, epigenetics and neurocognitive outcomes in mid-childhood. Using a within-pair twin model, the primary aims are to (1) identify early-life epigenetic correlates of neurocognitive outcomes; (2) determine the developmental stability of epigenetic effects and (3) identify modifiable environmental risk factors. Secondary aims are to identify factors influencing gut microbiota between 6 and 11 years of age to investigate links between gut microbiota and neurodevelopmental outcomes in mid-childhood. Approximately 210 twin pairs will undergo an assessment at 11 years of age. This includes a direct child cognitive assessment, multimodal magnetic resonance imaging, biological sampling, anthropometric measurements and a range of questionnaires on health and development, behavior, dietary habits and sleeping patterns. Data from complementary data sources, including the National Assessment Program - Literacy and Numeracy and the Australian Early Development Census, will also be sought. Following on from our previous focus on relationships between growth, cardiovascular health and oral health, this next phase of PETS will significantly advance our understanding of the environmental interactions that shape the developing brain.

Supragingival Plaque Microbiome Ecology and Functional Potential in the Context of Health and Disease.

To address the question of how microbial diversity and function in the oral cavities of children relates to caries diagnosis, we surveyed the supragingival plaque biofilm microbiome in 44 juvenile twin pairs. Using shotgun sequencing, we constructed a genome encyclopedia describing the core supragingival plaque microbiome. Caries phenotypes contained statistically significant enrichments in specific genome abundances and distinct community composition profiles, including strain-level changes. Metabolic pathways that are statistically associated with caries include several sugar-associated phosphotransferase systems, antimicrobial resistance, and metal transport. Numerous closely related previously uncharacterized microbes had substantial variation in central metabolism, including the loss of biosynthetic pathways resulting in auxotrophy, changing the ecological role. We also describe the first complete Gracilibacteria genomes from the human microbiome. Caries is a microbial community metabolic disorder that cannot be described by a single etiology, and our results provide the information needed for next-generation diagnostic tools and therapeutics for caries.IMPORTANCE Oral health has substantial economic importance, with over $100 billion spent on dental care in the United States annually. The microbiome plays a critical role in oral health, yet remains poorly classified. To address the question of how microbial diversity and function in the oral cavities of children relate to caries diagnosis, we surveyed the supragingival plaque biofilm microbiome in 44 juvenile twin pairs. Using shotgun sequencing, we constructed a genome encyclopedia describing the core supragingival plaque microbiome. This unveiled several new previously uncharacterized but ubiquitous microbial lineages in the oral microbiome. Caries is a microbial community metabolic disorder that cannot be described by a single etiology, and our results provide the information needed for next-generation diagnostic tools and therapeutics for caries.

Quantitation of the cellular content of saliva and buccal swab samples.

Buccal swabs and saliva are the two most common oral sampling methods used for medical research. Often, these samples are used interchangeably, despite previous evidence that both contain buccal cells and blood leukocytes in different proportions. For some research, such as epigenetic studies, the cell types contributing to the analysis are highly relevant. We collected such samples from twelve children and twenty adults and, using Papanicolaou staining, measured the proportions of epithelial cells and leukocytes through microscopy. To our knowledge, no studies have compared cellular heterogeneity in buccal swab and saliva samples from adults and children. We confirmed that buccal swabs contained a higher proportion of epithelial cells than saliva and that children have a greater proportion of such cells in saliva compared to adults. At this level of resolution, buccal swabs and saliva contained similar epithelial cell subtypes. Gingivitis in children was associated with a higher proportion of leukocytes in saliva samples but not in buccal swabs. Compared to more detailed and costly methods such as flow cytometry or deconvolution methods used in epigenomic analysis, the procedure described here can serve as a simple and low-cost method to characterize buccal and saliva samples. Microscopy provides a low-cost tool to alert researchers to the presence of oral inflammation which may affect a subset of their samples. This knowledge might be highly relevant to their specific research questions, may assist with sample selection and thus might be crucial information despite the ability of data deconvolution methods to correct for cellular heterogeneity.

Protocol for a longitudinal twin birth cohort study to unravel the complex interplay between early-life environmental and genetic risk factors in health and disease: the Chongqing Longitudinal Twin Study (LoTiS).

INTRODUCTION: Non-communicable diseases (NCD) now represent the major burden of adverse health in most countries. It is clear that much of the risk of such conditions begins very early in life, potentially in utero. Given their complex aetiology, an understanding of the origins of NCD requires an in-depth analysis of the interplay between genetic variation and environment, preferably over time. For decades, twin studies have played a key role in understanding such traits. Their strength lies in the ability to disentangle genetic and environmental factors that contribute to a phenotype. This is done by comparing genetically identical monozygotic (MZ) with dizygotic twins, who share on average 50% of genetic variation, or by comparing MZ twins within a pair. This study aims to determine the relative contributions of genes and environment to early-onset intermediate phenotypes related to later adult onset disease (such as growth and neurodevelopment) and to identify specific biomarkers and time points for emergence of phenotypes from infancy, largely independent of underlying genetic factors. METHODS/DESIGN: The Chongqing Longitudinal Twin Study (LoTiS) will recruit 300 women pregnant with twins, enriched for MZ pregnancies, with follow-up to 3 years of age. Data collection will be undertaken at key time points in gestation (×3), at delivery and postnatally (×9). Maternal and infant biospecimens including blood, urine, hair, nails and buccal swabs along with measures such as fetal scans and body measurements will be collected. Additional information from questionnaires and medical records includes pregnancy, diet, sociodemographics, maternal stress, and infant growth and neurodevelopment. ETHICS AND DISSEMINATION: This study has been approved by the Ethics Committee of Chongqing Medical University (record no: 201530) and has been registered with the Chinese Clinical Trial Registry (registry no: ChiCTR-OOC-16008203). Results of the recruitment and all subsequent analyses will be submitted for publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ChiCTR-OOC-16008203; Results.

Host Genetic Control of the Oral Microbiome in Health and Disease.

Host-associated microbial communities are influenced by both host genetics and environmental factors. However, factors controlling the human oral microbiome and their impact on disease remain to be investigated. To determine the combined and relative effects of host genotype and environment on oral microbiome composition and caries phenotypes, we profiled the supragingival plaque microbiome of 485 dizygotic and monozygotic twins aged 5-11. Oral microbiome similarity always increased with shared host genotype, regardless of caries state. Additionally, although most of the variation in the oral microbiome was determined by environmental factors, highly heritable oral taxa were identified. The most heritable oral bacteria were not associated with caries state, did not tend to co-occur with other taxa, and decreased in abundance with age and sugar consumption frequency. Thus, while the human oral microbiome composition is influenced by host genetic background, potentially cariogenic taxa are likely not controlled by genetic factors.

WITHDRAWN: Community-based population-level interventions for promoting child oral health.

BACKGROUND: Dental caries and gingival and periodontal disease are commonly occurring, preventable chronic conditions. Even though much is known about how to treat oral disease, currently we do not know which community-based population-level interventions are most effective and equitable in preventing poor oral health. OBJECTIVES: Primary • To determine the effectiveness of community-based population-level oral health promotion interventions in preventing dental caries and gingival and periodontal disease among children from birth to 18 years of age. Secondary • To determine the most effective types of interventions (environmental, social, community and multi-component) and guiding theoretical frameworks.• To identify interventions that reduce inequality in oral health outcomes.• To examine the influence of context in the design, delivery and outcomes of interventions. SEARCH METHODS: We searched the following databases from January 1996 to April 2014: MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Education Resource Information Center (ERIC), BIOSIS Previews, Web of Science, the Database of Abstracts of Reviews of Effects (DARE), ScienceDirect, Sociological Abstracts, Social Science Citation Index, PsycINFO, SCOPUS, ProQuest Dissertations & Theses and Conference Proceedings Citation Index - Science. SELECTION CRITERIA: Included studies were individual- and cluster-randomised controlled trials (RCTs), controlled before-and-after studies and quasi-experimental and interrupted time series. To be included, interventions had to target the primary outcomes: dental caries (measured as decayed, missing and filled deciduous teeth/surfaces, dmft/s; Decayed, Missing and Filled permanent teeth/surfaces, DMFT/S) and gingival or periodontal disease among children from birth to 18 years of age. Studies had to report on one or more of the primary outcomes at baseline and post intervention, or had to provide change scores for both intervention and control groups. Interventions were excluded if they were solely of a chemical nature (e.g. chlorhexidine, fluoride varnish), were delivered primarily in a dental clinical setting or comprised solely fluoridation. DATA COLLECTION AND ANALYSIS: Two review authors independently performed screening, data extraction and assessment of risk of bias of included studies (a team of six review authors - four review authors and two research assistants - assessed all studies). We calculated mean differences with 95% confidence intervals for continuous data. When data permitted, we undertook meta-analysis of primary outcome measures using a fixed-effect model to summarise results across studies. We used the I2 statistic as a measure of statistical heterogeneity. MAIN RESULTS: This review includes findings from 38 studies (total n = 119,789 children, including one national study of 99,071 children, which contributed 80% of total participants) on community-based oral health promotion interventions delivered in a variety of settings and incorporating a range of health promotion strategies (e.g. policy, educational activities, professional oral health care, supervised toothbrushing programmes, motivational interviewing). We categorised interventions as dietary interventions (n = 3), oral health education (OHE) alone (n = 17), OHE in combination with supervised toothbrushing with fluoridated toothpaste (n = 8) and OHE in combination with a variety of other interventions (including professional preventive oral health care, n = 10). Interventions generally were implemented for less than one year (n = 26), and only 11 studies were RCTs. We graded the evidence as having moderate to very low quality.We conducted meta-analyses examining impact on dental caries of each intervention type, although not all studies provided sufficient data to allow pooling of effects across similar interventions. Meta-analyses of the effects of OHE alone on caries may show little or no effect on DMFT (two studies, mean difference (MD) 0.12, 95% confidence interval (CI) -0.11 to 0.36, low-quality evidence), dmft (three studies, MD -0.3, 95% CI -1.11 to 0.52, low-quality evidence) and DMFS (one study, MD -0.01, 95% CI -0.24 to 0.22, very low-quality evidence). Analysis of studies testing OHE in combination with supervised toothbrushing with fluoridated toothpaste may show a beneficial effect on dmfs (three studies, MD -1.59, 95% CI -2.67 to -0.52, low-quality evidence) and dmft (two studies, MD -0.97, 95% CI -1.06 to -0.89, low-quality evidence) but may show little effect on DMFS (two studies, MD -0.02, 95% CI -0.13 to 0.10, low-quality evidence) and DMFT (three studies, MD -0.02, 95% CI -0.11 to 0.07, moderate-quality evidence). Meta-analyses of two studies of OHE in an educational setting combined with professional preventive oral care in a dental clinic setting probably show a very small effect on DMFT (-0.09 weighted mean difference (WMD), 95% CI -0.1 to -0.08, moderate-quality evidence). Data were inadequate for meta-analyses on gingival health, although positive impact was reported. AUTHORS' CONCLUSIONS: This review provides evidence of low certainty suggesting that community-based oral health promotion interventions that combine oral health education with supervised toothbrushing or professional preventive oral care can reduce dental caries in children. Other interventions, such as those that aim to promote access to fluoride, improve children's diets or provide oral health education alone, show only limited impact. We found no clear indication of when is the most effective time to intervene during childhood. Cost-effectiveness, long-term sustainability and equity of impacts and adverse outcomes were not widely reported by study authors, limiting our ability to make inferences on these aspects. More rigorous measurement and reporting of study results would improve the quality of the evidence.

Community-based population-level interventions for promoting child oral health.

BACKGROUND: Dental caries and gingival and periodontal disease are commonly occurring, preventable chronic conditions. Even though much is known about how to treat oral disease, currently we do not know which community-based population-level interventions are most effective and equitable in preventing poor oral health. OBJECTIVES: Primary • To determine the effectiveness of community-based population-level oral health promotion interventions in preventing dental caries and gingival and periodontal disease among children from birth to 18 years of age. Secondary • To determine the most effective types of interventions (environmental, social, community and multi-component) and guiding theoretical frameworks.• To identify interventions that reduce inequality in oral health outcomes.• To examine the influence of context in the design, delivery and outcomes of interventions. SEARCH METHODS: We searched the following databases from January 1996 to April 2014: MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Education Resource Information Center (ERIC), BIOSIS Previews, Web of Science, the Database of Abstracts of Reviews of Effects (DARE), ScienceDirect, Sociological Abstracts, Social Science Citation Index, PsycINFO, SCOPUS, ProQuest Dissertations & Theses and Conference Proceedings Citation Index - Science. SELECTION CRITERIA: Included studies were individual- and cluster-randomised controlled trials (RCTs), controlled before-and-after studies and quasi-experimental and interrupted time series. To be included, interventions had to target the primary outcomes: dental caries (measured as decayed, missing and filled deciduous teeth/surfaces, dmft/s; Decayed, Missing and Filled permanent teeth/surfaces, DMFT/S) and gingival or periodontal disease among children from birth to 18 years of age. Studies had to report on one or more of the primary outcomes at baseline and post intervention, or had to provide change scores for both intervention and control groups. Interventions were excluded if they were solely of a chemical nature (e.g. chlorhexidine, fluoride varnish), were delivered primarily in a dental clinical setting or comprised solely fluoridation. DATA COLLECTION AND ANALYSIS: Two review authors independently performed screening, data extraction and assessment of risk of bias of included studies (a team of six review authors - four review authors and two research assistants - assessed all studies). We calculated mean differences with 95% confidence intervals for continuous data. When data permitted, we undertook meta-analysis of primary outcome measures using a fixed-effect model to summarise results across studies. We used the I2 statistic as a measure of statistical heterogeneity. MAIN RESULTS: This review includes findings from 38 studies (total n = 119,789 children, including one national study of 99,071 children, which contributed 80% of total participants) on community-based oral health promotion interventions delivered in a variety of settings and incorporating a range of health promotion strategies (e.g. policy, educational activities, professional oral health care, supervised toothbrushing programmes, motivational interviewing). We categorised interventions as dietary interventions (n = 3), oral health education (OHE) alone (n = 17), OHE in combination with supervised toothbrushing with fluoridated toothpaste (n = 8) and OHE in combination with a variety of other interventions (including professional preventive oral health care, n = 10). Interventions generally were implemented for less than one year (n = 26), and only 11 studies were RCTs. We graded the evidence as having moderate to very low quality.We conducted meta-analyses examining impact on dental caries of each intervention type, although not all studies provided sufficient data to allow pooling of effects across similar interventions. Meta-analyses of the effects of OHE alone on caries may show little or no effect on DMFT (two studies, mean difference (MD) 0.12, 95% confidence interval (CI) -0.11 to 0.36, low-quality evidence), dmft (three studies, MD -0.3, 95% CI -1.11 to 0.52, low-quality evidence) and DMFS (one study, MD -0.01, 95% CI -0.24 to 0.22, very low-quality evidence). Analysis of studies testing OHE in combination with supervised toothbrushing with fluoridated toothpaste may show a beneficial effect on dmfs (three studies, MD -1.59, 95% CI -2.67 to -0.52, low-quality evidence) and dmft (two studies, MD -0.97, 95% CI -1.06 to -0.89, low-quality evidence) but may show little effect on DMFS (two studies, MD -0.02, 95% CI -0.13 to 0.10, low-quality evidence) and DMFT (three studies, MD -0.02, 95% CI -0.11 to 0.07, moderate-quality evidence). Meta-analyses of two studies of OHE in an educational setting combined with professional preventive oral care in a dental clinic setting probably show a very small effect on DMFT (-0.09 weighted mean difference (WMD), 95% CI -0.1 to -0.08, moderate-quality evidence). Data were inadequate for meta-analyses on gingival health, although positive impact was reported. AUTHORS' CONCLUSIONS: This review provides evidence of low certainty suggesting that community-based oral health promotion interventions that combine oral health education with supervised toothbrushing or professional preventive oral care can reduce dental caries in children. Other interventions, such as those that aim to promote access to fluoride, improve children's diets or provide oral health education alone, show only limited impact. We found no clear indication of when is the most effective time to intervene during childhood. Cost-effectiveness, long-term sustainability and equity of impacts and adverse outcomes were not widely reported by study authors, limiting our ability to make inferences on these aspects. More rigorous measurement and reporting of study results would improve the quality of the evidence.

Natural history of dental caries in very young Australian children.

BACKGROUND: Whilst the global burden of caries is increasing, the trajectory of decay in young children and the point at which prevention should occur has not been well established. AIM: To identify the 'natural history' of dental caries in early childhood. DESIGN: A birth cohort study was established with 467 mother/child dyads followed at 1, 6, 12, 18, and 36 months of age. Parent-completed surveys captured demographic, social, and behavioural data, and oral examinations provided clinical and data. RESULTS: Eight per cent of children (95% confidence interval (CI): 5-12%) at 18 months and 23% (95% CI: 18-28%) at 36 months experienced decay. Interesting lesion behaviour was found between 18 and 36 months, with rapid development of new lesions on sound teeth (70% of teeth, 95% CI: 63-76%) and regression of many lesions from non-cavitated lesions to sound (23% of teeth, 95% CI: 17-30%). Significant associations were found between soft drink consumption and lesion progression. CONCLUSIONS: Findings suggest optimal time periods for screening and prevention of a disease which significantly impacts multiple health and well-being outcomes across the life course.

A systematic review of risk factors during first year of life for early childhood caries.

BACKGROUND: Early childhood caries (ECC) describes dental caries affecting children aged 0-71 months. Current research suggests ECC has important aetiological bases during the first year of life. Gaps in knowledge about disease progression prevent the effective and early identification of 'at risk' children. AIM: To conduct a systematic review of research studies focusing on (a) acquisition and colonization of oral bacteria and ECC and (b) risk and/or protective factors in infants aged 0-12 months. DESIGN: Ovid Medline and Embase databases (1996-2011) were searched for RCT, longitudinal, cross-sectional and qualitative studies. Two investigators undertook a quality assessment for risk of bias. RESULTS: Inclusion criteria were met for (a) by four papers and for (b) by 13 papers; five papers were rated medium or high quality. Bacterial acquisition/colonization and modifying factor interrelationships were identified, but their role in the caries process was not clarified. Key risk indicators were infant feeding practices (nine papers), maternal circumstances and oral health (6) and infant-related oral health behaviours (4). CONCLUSION: This review confirmed that factors occurring during the first year of life affect ECC experience. Despite heterogeneity, findings indicated maternal factors influence bacterial acquisition, whereas colonization was mediated by oral health behaviours and practices and feeding habits.