Stunting Is Associated with Altered Periodontal Host–Microbe Interactions and Responses to Oral Probiotic and Antiseptic Interventions in Children

Objectives: To determine whether stunting modifies periodontal microbial dynamics, inflammatory responses, and short-term responses to oral interventions in children. Materials and Methods: This open-label, non-randomized study included 36 children aged 8–12 years, comprising 18 children with stunting and 18 without stunting. Stunting was defined as a Height-for-Age Z-score below 2 standard deviations according to World Health Organization criteria. Participants received a probiotic, an essential-oil intervention, or no active intervention for 14 days. Gingival swab and dental plaque samples were collected at baseline and Day 14. Porphyromonas gingivalis and Treponema denticola abundance and IL-1β and IL-6 mRNA expression were quantified using species or target-specific quantitative PCR. Each outcome was analyzed using a linear mixed effects model incorporating stunting status, treatment, time, and their interactions as fixed effects and participant as a random intercept. Exploratory Spearman correlations were used to evaluate microbial inflammatory relationships. Results: Stunting status was significantly associated with the abundance of both P. gingivalis (p = 0.036) and T. denticola (p = 0.043). For P. gingivalis, a significant stunting status by time interaction was observed (p = 0.008), indicating that its temporal trajectory differed between children with and without stunting. No significant treatment effect or treatment related interaction was detected for either bacterial species. IL-1β expression changed significantly over time (p = 0.027) and displayed substantial interindividual variability, particularly among children with stunting receiving the essential oil intervention; however, its group and treatment related effects were not significant. IL-6 expression remained comparatively stable, with no significant main or interaction effects. Exploratory correlations suggested contrasting cytokine coordination at baseline: IL-1β and IL-6 were positively correlated in children without stunting (r = 0.75) but negatively correlated in children with stunting (r = −0.58). Conclusions: Stunting was associated with differences in periodontal pathogen abundance, a distinct temporal response of P. gingivalis, and altered coordination of inflammatory markers. These findings suggest that nutritional status may modify periodontal microbial–immune relationships and highlight the need for larger randomized studies to determine whether stunting influences responses to oral health interventions.