Preliminary Insights into Association of Growth Factors with Hypodontia: A Clinical Study

Hypodontia, defined as the congenital absence of teeth, may reflect underlying disturbances in molecular pathways regulating odontogenesis. This pilot cross-sectional study aimed to investigate whether systemic levels of insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), and human growth hormone (HGH) differ between individuals with congenital bilateral absence of mandibular second premolars and individuals with normal dentition.

Twenty-two participants aged 12-31 years were included and allocated into two groups: individuals with congenital bilateral absence of mandibular second premolars (n = 11) and age- and sex-matched controls (n = 11). Hypodontia was confirmed using panoramic radiographs. Plasma concentrations of IGF-I, IGF-II, IGFBP-2, IGFBP-3, IGFBP-4, IGFBP-6, and HGH were measured via multiplex magnetic bead assays. Between-group comparisons were performed using the Mann-Whitney U-test.

No statistically significant differences in the IGF-I (p = 0.897), IGF-II (p = 0.519), IGFBP-2 (p = 0.573), IGFBP-3 (p = 0.189), IGFBP-4 (p = 0.380), IGFBP-6 (p = 0.193), or HGH levels (p = 0.747) were observed between the hypodontia and control groups. Exploratory analyses suggested age- and body mass index-related variability in the IGF-I levels, indicating potential metabolic influences on circulating growth factor profiles.

In this small exploratory cohort, the systemic IGF, IGFBP, and HGH levels did not differ significantly between the individuals with and without hypodontia. These findings suggest that circulating growth factor alterations are unlikely to play a dominant role in nonsyndromic mandibular second premolar agenesis. Larger, well-controlled studies incorporating tissue-specific or genetic analyses are required to clarify the biological mechanisms underlying hypodontia.