Human permanent tooth sizes are associated with genes encoding oestrogen receptors

Abstract

Objective: To evaluate if genetic polymorphisms in the oestrogen receptor 1 ( ESR1) and oestrogen receptor 2 ( ESR2) genes encoded for oestrogen receptors alpha (ERα) and beta (ERβ) are involved in permanent tooth size. Design: Cross-sectional study. Setting: Orthodontic Clinic at School of Dentistry of Ribeirão Preto, University of São Paulo. Participants: A total of 108 orthodontic patients. Materials and Methods: Pre-treatment orthodontic records were evaluated. Dental casts were used to determine the maximum crown measurements of fully erupted permanent teeth in the mesiodistal dimensions. Second and third molars were not included in the analysis. Genomic DNA samples were used for the genotyping of four genetic polymorphisms: ESR1 (rs9340799 and rs2234693) and ESR2 (rs1256049 and rs4986938). The associations between tooth size and sex were evaluated using t test. The associations between tooth size and genotype were analysed with linear regression and adjusted by sex at an alpha of P⩽0.05. Results: Female patients presented smaller tooth size than male patients. A statistically significant difference was observed in almost all teeth ( P<0.05). The genetic polymorphisms in rs9340799, rs2234693, rs1256049 and rs4986938 were associated with some tooth sizes in both the maxilla and mandible ( P<0.05). Conclusion: This study provides evidence that genetic polymorphisms in ESR1 and ESR2 could be associated with tooth size in permanent teeth.

Polymorphisms in hormonal‐related genes might be associated with variations in permanent tooth crown size

“…5 The evidence of a sexual dimorphism present in human teeth has led many studies to suggest a hormonal influence throughout odontogenesis where the hormones may be differentially expressed depending on the sex. [4][5][6] Many studies also suggest that variations in TCS may be influenced by different ethnic groups. 27,28 However, in our results the ethnic group was not associated with TCS variation.…”

“…39 Moreover, rats with low levels of estrogens presented a reduction of microhardness of incisor enamel, indicating a possible role in amelogenesis as well. 40 Even though other studies have associated polymorphism in ESR1 with variations in TCS, 6 and developmental defects of enamel in humans, 41 would be required with a greater sample size and evaluate the whole extension of ESR1, ESR2 and PTH genes, to validate the results.…”

“…3 One factor that could account for the variability in tooth crown size (TCS) is hormonal activity since it has been reported that the variability in TCS can be observed between sex and it may be explained by the differences in hormonal balance. [4][5][6] Oestrogen is a sex hormone that regulates several physiological processes, including normal proliferation, development and…”

“…Additionally, our previous study suggested that ESR1 and ESR2 polymorphisms are involved with the size of some permanent teeth. 6 The parathyroid hormone (PTH) is secreted by the parathyroid gland, with a key role in the metabolism of calcium and phosphorus, influencing the mineralization of bone and teeth. 12 To date, no evidence in the literature confirms the influence of genetic polymorphisms in PTH with TCS variability.…”

“…20 Thus, it is of great interest to investigate associated factors that could be involved in the variability of TCS, including the set of molecules underlying the determination of tooth development. Some studies have been performed to evaluate genes involved in this variability, 6,16,19,21 however, there is still limited evidence on the hormonal-related genes' contributions to TCS. Therefore, this study aimed to evaluate whether patientassociated factors and genetic polymorphisms in ESR1, ESR2 and PTH genes are associated with the mesiodistal (MD) and buccolingual (BL) TCS of permanent teeth.…”