en Genetics & Disease Genetics & Disease Original Article Original Article <div style="text-align: justify;">Dental decay is a disease that is greatly affected by environmental components, but recently there have been an increasing number of documents supporting a genetic factor in the development of caries. The purpose of this study was to examine the association between dental caries and single-nucleotide polymorphisms in the <em>AMELX</em> gene. This research was carried out on 360 individuals of both sexes, who were referred to the dental school at the Shiraz University of Medical Sciences. In this research, individuals aged from 20&ndash;65 years were divided into two groups: controls (decayed, missed, or filled teeth (DMFT) &le; 5; n = 180) and cases (DMFT &ge; 14; n = 180). The tetra-primer ARMS-PCR technique was performed for genotyping the DNA extracted from blood cells. Analysis of the <em>AMELX</em> rs946252 polymorphism showed that the T allele of rs946252 was a significant protective factor against dental caries in Iranian adults (T vs. C: OR = 0.70, 95% CI: 0.49&ndash;0.98, P = 0.04). We demonstrated the significant differences in the genotype frequencies under two genetic models: overdominant (TC vs. TT + CC: OR 0.35, 95% CI 0.19&ndash;0.64, P = 0.0006) and recessive (CC vs. TC + TT: OR 2.57, 95% CI 1.39&ndash;4.76, P = 0.002). Our results show that the SNPs of the <em>AMELX </em>gene may be related with susceptibility to dental caries in Iranian adults.</div> Dental caries, DMFT, AMELX, rs946252, Tetra-primer ARMS-PCR 294 299 http://ijmcmed.org/browse.php?a_code=A-10-1900-1&slc_lang=en&sid=1 Fatemeh Koohpeima koohpeima.f@gmail.com 100319475328460016664 100319475328460016664 No Department of Operative Dentistry, Biomaterial Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. Maryam Derakhshan allahyari.mahmood@yahoo.com 100319475328460016665 100319475328460016665 No Department of Operative Dentistry, Biomaterial Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. Mohammad Javad Mokhtari mj.mokhtari@gmail.com 100319475328460016666 100319475328460016666 Yes Young Researchers and Elite Club, Department of Biology, Zarghan Branch, Islamic Azad University, Zarghan, Iran.