Oral microbiota dysbiosis; mechanisms driving systemic bone loss and osteoporosis risk

Oral microbiota dysbiosis, particularly in periodontitis, represents a significant yet under-recognized contributor to systemic bone loss and heightened osteoporosis risk. Disruption of the symbiotic oral microbial community permits pathobiont expansion, notably Porphyromonas gingivalis triggering chronic gingival inflammation. This local inflammatory milieu drives alveolar bone resorption through receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated osteoclastogenesis and matrix metalloproteinase activation. Notably, these pathological processes extend beyond the oral cavity by three interconnected mechanisms of hematogenous dissemination of periodontal pathogens and their virulence factors, which directly stimulate osteoclast differentiation in distant skeletal sites and by systemic spillover of pro-inflammatory cytokines, amplifying bone-resorptive signaling throughout the skeleton, across with dysregulation of the gut-bone axis, as oral pathobionts translocate to the gastrointestinal tract, altering gut permeability and microbiome composition to further exacerbate inflammatory bone loss. Epidemiological studies consistently associate periodontitis with reduced bone mineral density and increased fracture incidence, independent of traditional osteoporosis risk factors. Animal models confirm that oral pathogen challenge accelerates trabecular bone loss in long bones and vertebrae. These findings position oral dysbiosis as a modifiable risk factor for osteoporosis, suggesting that periodontal therapy and microbiome-targeted interventions may offer adjunctive strategies for skeletal health preservation. Future research should prioritize longitudinal human studies to establish causality and evaluate whether periodontal treatment attenuates systemic bone loss trajectories in at-risk populations.