Method: A total of 677 12-yr-old students were selected from Curitiba (PR), Brazil, 6 public and 6 private schools: 346 with (DMFT≥1) and 331 without caries experience (DMFT=0). Also, individuals concentrating higher levels of disease (polarization group, DMFT≥2, n=253) were tested against those with DMFT≤1 (n=424), (mean DMFT=1,23 in Curitiba). Along with clinical parameters (fluorosis, salivary flow, buffer capacity, gingivitis, and presence of plaque), LTF tag SNPs (rs11716497, rs2073495, and rs6441989) were analyzed using univariate analysis and multivariate logistic regression model (p<0.05).
Result: Allele A for tag SNP rs6441989 was found to be significantly less frequent in the polarization group, conferring a protective effect against caries experience [AA+AG x GG (OR: 0.710, CI: 0.514-0.980, p=0.045)], which remained significantly associated with caries protection in the presence of gingivitis (p=0.020) and plaque (p=0.035).
Conclusion: Allele A for polymorphism rs6441989 of LTF gene was associated with protection against dental caries in the presence of clinical variables such as gingivitis and plaque. Saliva is one of the host factors that interact with the biofilm, avoiding enamel demineralization caused by acids resulting from cariogenic bacteria metabolism. Therefore, the identification of salivary factors polymorphisms involved with caries development might contribute for the unveiling towards caries genetic background.