Study Population Principal inclusion criteria will be age range (30-55 years) and the presence of at least one cavitated caries lesion, but no more than three. Subjects with systemic disease that interfered with the oral ecosystem will be excluded. The caries criterion will be designed to include participants who are at risk of forming new lesions. Sample size for preliminary screening will be calculated on the basis of previous studies regarding caries prevalence (about 26%) in adults [Campus et al, 2011] and relative odds ratio 2.88 of incidence, as reported in literature [Ito et al, 2011]. Thus, the theoretical sample size for preliminary screening will be set to 1200 subjects.