Prenatal maternal salivary hormones and timing of tooth eruption in early childhood: a prospective birth cohort study

Ying Meng^1*Ruqian Yang²Nora Alomeir²Tom O'Connor³Jerod M Rasmussen⁴Felicitas B Bidlack⁵Jin Xiao²

• ¹University of Rochester School of Nursing, Rochester, United States
• ²Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, United States
• ³Departments of Psychiatry, Neuroscience, Obstetrics and Gynecology, University of Rochester Medical Center, Rochester, United States
• ⁴Department of Pediatrics, University of California Irvine, Irvine, United States
• ⁵Craniofacial Biology and Bioengineering, ADA Forsyth Institute, Somerville, United States

Background: Although the mechanisms underlying tooth eruption are not fully understood, the prenatal maternal milieu, particularly stress exposures, appears to play an important role in dental development. Yet, limited research has investigated the influence of prenatal stress and stress-related hormones on tooth eruption. Methods: This study included 142 mother-child dyads from a birth cohort to examine associations between prenatal stress, stress-related hormones, and primary tooth eruption. The number of erupted teeth was assessed by dentists at child visits through 24 months of age. Maternal prenatal depression and anxiety diagnoses were extracted from medical records as a proxy for stress. Stress-related hormone concentrations, including cortisol, estradiol, progesterone, testosterone, triiodothyronine (T3), and thyroxine (T4), were measured from salivary samples collected in late pregnancy. Generalized linear models were used to assess associations between prenatal stress, stress-related hormones, and tooth eruption, adjusting for relevant covariates. Results: Eruption timing varied within our cohort: 15.2% of children had at least one erupted tooth by 6 months, and 25% had all 20 primary teeth by 24 months. Correlations in tooth counts across visits ranged from 0.15 to 0.57. Several prenatal maternal hormones, including cortisol, estradiol, progesterone, testosterone, and T3, were significantly and positively associated with the number of erupted teeth at individual visits (p<0.05). Particularly, higher prenatal cortisol levels were associated with more erupted teeth at 6 months, corresponding to an average difference of ~4 teeth between the lowest and highest cortisol levels. Conclusion: Maternal salivary hormone levels in late pregnancy may contribute to variations in primary tooth eruption during the first two years of life.