Breaking the Cycle: Real-Time Family Oral Microbial Transmission Patterns as Intervention Targets

Overview

This study aims to understand how oral bacteria that cause tooth decay and gum disease spread among family members and whether treating multiple family members can reduce the return of these bacteria after dental treatment. Families with children aged 5-12 years will be recruited from university dental clinics. Participants will be assigned to one of three treatment groups: treatment for the child only, treatment for the child and parents, or treatment for all family members. Researchers will collect oral bacterial samples from family members before and after treatment and will monitor close-contact interactions within the household using wearable proximity-tracking devices. The study will also collect information about oral health habits, family interactions, and environmental factors that may influence bacterial transmission. By combining bacterial DNA analysis with information about family contact patterns, researchers hope to better understand how oral bacteria are shared within households and whether family-based treatment approaches can reduce bacterial recolonization after dental therapy. The results of this study may help improve strategies for preventing childhood tooth decay and gum disease by addressing family-level sources of bacterial transmission.

Oral diseases, including dental caries and periodontal diseases, are among the most prevalent chronic diseases worldwide. Although oral pathogens are known to be transmissible, the mechanisms by which disease-associated bacteria spread within families and contribute to recolonization after treatment remain poorly understood. This randomized clinical trial will investigate familial oral microbial transmission and the role of household-level interventions in modifying microbial recolonization following professional dental therapy. Forty-five families will be recruited from university dental clinics and randomized into one of three intervention groups: (A) child-only plaque disruption, (B) child plus parent plaque disruption, or (C) plaque disruption for all family members. Eligible households must include at least two children aged 5-12 years and at least one adult requiring periodontal therapy or a child at high risk of disease recurrence. Oral microbial samples will be collected from all participating family members at multiple oral sites, including saliva, buccal mucosa, tongue, supragingival plaque, and subgingival plaque. Follow-up sampling will occur at 1 week, 4-6 weeks, and 3 months after treatment. Participants will complete oral health and demographic questionnaires, and all family members will wear Ultrawide Band (UWB) proximity-tracking devices to quantify real-time interpersonal contact patterns within the household. Airborne microbial sampling will also be performed to investigate potential aerosol-mediated transmission pathways. Bacterial DNA sequencing, source-tracking algorithms, and quantitative PCR analyses will be used to identify sources of microbial recolonization and quantify transmission among family members. Generalized Linear Mixed Models will be used to examine associations between microbial transmission, proximity measures, demographic variables, and household characteristics. The primary objective is to determine whether reducing familial pathogen burden through household-level treatment decreases recolonization of oral pathogens following dental therapy. Secondary objectives include characterizing contact-dependent and airborne transmission pathways and identifying factors associated with oral microbial transmission within families.