Correlation between unstimulated salivary flow, pH and streptococcus mutans, analysed with real time PCR, in caries-free and caries-active children.

Aim Evaluate the correlations between un-stimulated salivary flow, pH and level of S. mutans, analysed through real time PCR, in caries-free and caries-active children. Materials and methods Thirty healthy children were divided into 2 groups: test group (DMFT/dmft ≥3 and at least 1 active caries lesion) and control group (DMFT/ dmft=0). Un-stimulated saliva was collected, pH was measured and S. mutans and total bacterial amount were evaluated with real-time PCR analysis. Results Un-stimulated salivary flow in the test group was significantly lower (p = 0.0269) compared to group control. The level of S. mutans was higher in the test group (p = 0.176), and an inverse correlation was recorded between total bacterial amount and un-stimulated salivary flow (p = 0.063). In the control group a positive relationship was found between total bacterial amount and S. mutans (p = 0.045) and an inverse correlation between pH and S. mutans (p = 0.088). A t-test and a linear regression analysis were performed. Conclusion A higher salivary flow and an increased salivary pH seem to represent protective factors against caries in children, while high levels of S. mutans are correlated with caries active lesions. Caries risk assessment Correlation between un-stimulated salivary flow, pH and streptococcus mutans, analysed with real time PCR, in caries-free and caries-active children Introduction Dental caries is an infectious, chronic, degenerative and transmissible disease with a multifactorial aetiology. It is caused by demineralisation of the outermost layer of the teeth caused by the acidity of the bacterial plaque present on the enamel and it may lead to destruction of the tooth [Featherstone, 2003]. Three main risk factors for caries have been widely studied: the cariogenic bacterial flora, type of diet (frequency and presence of fermentable carbohydrates) and the host defense mechanisms [Loesche, 1986; Zhao et al., 2010; Thenisch et al., 2006; Keyes and Fitzgerald, 1963]. Recently a reduction in the prevalence of caries has been recorded in many industrialised countries, even if it still represents one of the most common diseases in the general population [Whelton, 2004; Hugoson, 2005; Selwitz et al., 2007]. Recent aepidemiological investigations done in Italy found that caries is still a pressing problem in children, showing a prevalence of respectively 22% and 44% in children aged 4 to 12 years [Campus et al., 2008; Campus et al., 2009]. To reach the goal of the World Health Organization (WHO) of "no caries" for 90% of children aged 5-6 years by 2020, more synergy between prevention programmes and a deeper knowledge of caries risk assessment are required. The aim of this study was to evaluate the interactions between salivary flow, pH and presence of S. mutans measured with a molecular protein chain reaction approach in caries-active and caries-free children, in order to obtain more data for the caries risk assessment of these patients. Material and methods Among the children referred to the Department of Dentistry of the University of Insubria, Varese (Italy), 30 healthy subjects were selected and divided into two groups as follows. • Test group: 19 patients (9 males and 10 females, average 8.8 years) with a DMFT/dmft≥3, with at least one caries lesion. • Control group: 11 patients (5 male and 6 female, average 8.1 years) with a DMFT/dmft=0. should be performed considering all parameters involved in the development of the disease.