Overall Effects of Risk Factors Associated with Dental Caries Indices Using the Marginalized Zero-Inflated Negative Binomial Model.

The purpose of this paper is to identify risk factors for decayed, missing, and filled permanent teeth (DMFT) in a population of 12-15-year-old schoolchildren and to apply the marginalized zero-inflated negative binomial (MZINB) model for determination and estimation of the overall effects of the risk factors. A cross-sectional survey comprising 764 students aged between 12 and 15 years was used to analyze the association between caries in children and some background characteristics in children and their parents. Information on the samples' social, behavioral, and demographic status was obtained through a series of closed questions. The incidence rate ratios (IRR) were used to associate some risk factors with caries. In the entire sample, the frequency of zero was 194 (25.4%). The result of the shared-parameter marginalized zero-inflated negative binomial (SP-MZINB) model showed that being a girl (IRR = 1.18; p value = 0.021), higher dental visits frequency (IRR = 1.20; p value <0.001), lower tooth brushing frequency (IRR = 0.91; p value = 0.019), higher flossing frequency (IRR = 1.11; p value = 0.001), and lower mothers' education (IRR = 0.89; p value = 0.042) are associated with DMFT. Our results may provide better insights of the factors associated with DMFT, and health programs should focus their efforts on healthcare services, for both preventive and curative purposes. This regression model provides an appropriate fit and meaningful interpretation to handling zero-inflated count outcomes. Also, it provides direct estimates of the effects of risk factors on the overall mean that does not require postmodeling computations.

Challenges impeding integration of oral health into primary health care.

The primary healthcare (PHC) services in the Islamic Republic of Iran have succeeded in addressing high levels of communicable diseases; however, they seem less able to deal with maternal and paediatric oral diseases. The aim of this study was to examine problems in integrating oral health services into PHC. This was a qualitative research study comprising focus group discussions and interviews. Five focus-group discussions were held with midwives, family healthcare practitioners, rural PHC workers, duty-service dentists, and public health dentists. Also, individual interviews were organized with experts of faculty members in related fields, informant managers and policy makers, and in-depth interviews were done with pregnant women in four PHC centres. Audiotapes were transcribed following each session, and then a qualitative thematic analysis was carried out on gathered data. Data analysis resulted in 4 main themes relating to the challenges: environmental, educational, organizational and school-based programme factors. This study provides a clearer understanding of the challenges of integrating oral health services into PHC.