Utilising surface-level data to explore surface, tooth, individual and family influence on the aetiology of hypomineralised second primary molars

OBJECTIVES: Hypomineralised second primary molars (HSPM) are common developmental enamel defects. The aims of this study were to use surface-level data to explore the clustering of HSPM at four levels (family, child, tooth, surface). METHODS: This study of 172 twin pairs was nested within the Peri/postnatal Epigenetic Twin Study. HSPM was measured by standardised oral examinations at age 6 years. Multilevel logistic regression models were fitted to assess the correlation structure of surface level data and variation in HSPM. The associations between surface level risk factors and HSPM were then explored using the multilevel logistic regression model using the best fitting correlation structure. RESULTS: The prevalence of HSPM was 68 (19.8%) children, with a total of 141 (10.3%) teeth and 264 tooth surfaces (6.3%) affected. Multilevel models revealed that a hierarchical structure accounting for correlation at the family, child and tooth level best accounted for the variation in HSPM. The estimated variances from the best fitting model (Model 3) were largest at the family level (12.27, 95% CI 6.68, 22.51) compared with 5.23 at the child level and 1.93 at the tooth level. Application of regression analysis utilising this three-level correlation structure identified tooth/surface level factors in addition to the previously identified familial and individual risk factors for HSPM. CONCLUSION: In addition to familial (environmental and genetic) and unique child-level factors, the aetiology of HSPM is likely to be influenced by local tooth-level factors

Glass ionomer cements Factors influencing their durability

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A qualitative study exploring barriers to a model of shared care for pre-school children's oral health

Objective To explore the oral health beliefs and practices of primary health care professionals which may act as barriers to the development of a model of shared care for the oral health of pre-school children. Design Qualitative focus group discussions and semi-structured interviews. Setting Four rural local government areas in Victoria, Australia, 2003. Subjects and methods Subjects: maternal and child health nurses, general medical practitioners, dental professionals and paediatricians working in the four local government areas. Data collection: discipline specific focus groups and semi-structured interviews. Data analysis: transcription, coding, clustering and thematic analysis. Results Several strong themes emerged from the data. All participants agreed that dental caries is a significant health issue for young children and their families. Beliefs about the aetiology of dental caries and its prevention were variable and often simplistic, focusing predominantly on diet. Dental professionals did not believe that they had a primary role in the oral health of pre-school aged children but that others particularly maternal and child health nurses did. However other health care professionals were not confident in assuming this role. Conclusions This study has identified important barriers and possible strategies for the development of an integrated and shared approach to preventing dental caries in pre-school aged children. Clear and consistent oral health information and agreed roles and responsibilities need to be developed

Parental knowledge, beliefs and behaviours for oral health of toddlers residing in rural Victoria

Background: Little is known about the oral health of children under the age of four years. The determinants of early childhood caries (ECC) in this young age group are also not well understood despite a growing recognition that early interventions may deliver the greatest benefits. The aim of this study was to examine the oral health‐related knowledge, attitudes and reported behaviours of parents of children aged 12–24 months living in rural areas of Victoria, Australia. Methods: A robust theoretical model was utilized to identify oral health‐related behaviours and their antecedent and reinforcing conditions within the context of this specific population group. Two hundred and ninety‐four parent/child dyads were recruited through their maternal and child health nurses as part of a larger intervention trial. Parents completed a self‐report questionnaire. Results: Knowledge regarding risk and protective factors amongst parents was variable and sometimes at odds with contemporary evidence. Knowledge of the role of early infection with S. mutans was very low, with high levels of behaviours that may promote early transmission reported. Tooth cleaning was reported by most parents at least sometimes, however a large proportion lacked confidence and this was significantly related to the frequency of the cleaning. Parents were confused about the fluoride status of their water supplies. Most parents believed fluoride toothpaste reduced the risk of ECC but did not know whether it should be used with toddlers. Conclusions: The results of this study have implications for efforts to prevent dental decay in this very young age group. Health care professionals other than dentists need support to provide information and promote confidence with regard to optimal fluoride exposure. Attention should also be given to the contribution of early contact with particular bacteria in oral health education and promotion programmes

A twin study of body mass index and dental caries in childhood

Sub-optimal nutrition and dental caries are both common with significant short and long-term implications for child health and development. We applied twin statistical methods to explore the relationship between body mass index (BMI) and dental caries. We measured BMI at 18 months and six years of age and cumulative dental caries experience at six years in 344 twin children. Dental caries in primary teeth was categorised into 'any' or 'advanced' and BMI was analysed as both a continuous and categorical variable. Statistical analyses included multiple logistic regression using generalized estimating equations and within/between-pair analyses. There was no association between BMI and 'any' dental caries experience at either time-point, neither overall nor in within/between pair analyses. However, 'advanced' dental caries at six years was associated with a within-pair difference in BMI of -0.55 kg/m2 (95% CI -1.00, -0.11, p = 0.015). A within-pair increase of 1 kg/m2 in BMI was associated with a lower within-pair risk of advanced dental caries (OR 0.68, 95% CI 0.52, 0.90, p = 0.007). These findings reveal a possible causal relationship between lower BMI and dental caries. As dental outcomes were only measured at one time point, the direction of this potentially causal relationship is unclear

On the structure-property relationship of sound and hypomineralized enamel

Developmental defects in dental enamel pose significant clinical challenges which have highlighted our limited understanding of the structure and properties of this tissue. In this study, we first investigated the contact-size dependence of the physical properties of sound and hypomineralized enamel, and then examined the microstructure to establish a structural basis for their differing properties. Depth-sensing indentation tests were carried out over a wide range of peak loads in a direction perpendicular to the enamel prisms. Hypomineralized enamel demonstrated stronger penetration dependence for measured hardness and elastic modulus than sound enamel. The microstructure of sound and hypomineralized enamel was observed using field emission scanning electron microscopy and transmission electron microscopy with support of a focused ion beam milling system. Images of sound enamel showed barely distinguishable sheath regions with minimal organic presence. In contrast, hypomineralized enamel showed thicker sheath structures surrounding the prisms and higher levels of organic content within both the prisms and the sheath regions. It is argued that the higher organic content within prism structure was responsible for an initial lower hardness and elastic modulus of hypomineralized enamel under low-load indentation. As the indentation depth increased, the thicker organic-rich sheath regions played a more important role in reducing the mechanical properties of the hypomineralized enamel. On the basis of Spears finite element model [Spears IR. A three-dimensional finite element model of prismatic enamel: a re-appraisal of the data on the Young's modulus of enamel. J Dental Res 1997; 76(10):1690-97], elastic moduli of sound and hypomineralized enamel were predicted, which matched experimental results.Z.-H. Xie, E.K. Mahoney, N.M. Kilpatrick, M.V. Swain and M. Hoffma