Purpose To investigate for the first time in Egypt and the Middle East the relationship between a specific gene and the presence of severely resorbed edentulous mandibular ridges in a sample of the Egyptian population. Materials and Methods The study was conducted on 50 subjects divided into case and control groups according to the residual ridge height. Saliva was used as a convenient source of DNA in the dental clinic. A certain genetic variation (1772C>T) in an important gene related to bone healing (hypoxia‐inducible factor‐1 alpha [HIF1‐α] gene) was selected. The genetic variation 1772C>T is a single nucleotide polymorphism (SNP) that occurs when corresponding sequences of DNA from different individuals differ at one base. Then, we have 2 forms of the gene (2 alleles): C and T. SNPs typically have 3 genotypes; in this study, they are the CC, CT, and TT genotypes. Polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) was the method performed for genotyping. The statistical significance of the results was evaluated by the Chi‐square test and Fisher Exact test. Results A statistically significant difference in the distribution of the TT genotype between both groups was detected with p‐value = 0.049. There was also a difference in the distribution of the CC and CT genotypes, but it was not statistically significant, since the p‐values were 0.733 and 0.145, respectively. The T alleles were more abundant in the case group, while the control group showed more frequency of the C allele with no statistical significance. Conclusion The TT genotype of the 1772C>T polymorphism of HIF1‐α gene is related to the presence of severely atrophied residual ridges in completely edentulous Egyptians. This can be used as a marker to predict the future condition of the ridge using saliva samples. Further studies on larger scale are recommended.

INTRODUCTION:Atrophic residual ridges have always been an obstacle for a successful prosthodontics treatment. Residual ridge resorption (RRR) was attributed to a combination of anatomical, metabolic and mechanical determinants. Lately, the genetic factor was considered since single nucleotide polymorphisms (SNPs) in relevant genes have been present in patients having severe RRR. OBJECTIVES:The aim of the current study was to investigate for the first time the relation between SNP 1772C>T in Hypoxia Inducible Factor-1 alpha (HIF-1α) gene and the presence of severely resorbed edentulous mandibular ridges in a sample of the Egyptian population. MATERIALS AND METHODS:The study was conducted on 50 subjects divided into case and control groups according to the residual ridge height. Saliva was used as a convenient source of DNA in the dental clinic. PCR-Restriction Fragment Length Polymorphism was performed for genotyping. RESULTS: A statistically significant difference in the distribution of the TT genotype between both groups was present. There was also a difference in the distribution of the CC and CT genotypes but it wasn't statistically significant. The T alleles were more abundant in the case group while the control group showed more frequency of the C allele with no statistical significance. CONCLUSIONS: This study concluded that the TT genotype of the 1772C>T polymorphism of HIF-1α gene is related to the presence of severely atrophied residual ridges. This SNP can be used as a marker to predict the future condition of the ridge using saliva samples. Further studies on larger scale are recommended.