Link Between Idiopathic Pain and Poor Oral Health Found

Because the oral cavity is the gateway to the rest of the body, it is also a primary avenue for pathogenic entry. In fact, research is continually linking oral pathogens to numerous chronic conditions. But what has not been established is the relationship between pain in sensitization disorders and oral microbiota.¹

Sensitization disorders, also known as central sensitization syndromes (CSS), are clinical conditions, in which pain of unknown etiology — nociplastic pain — figures prominently. Unlike nociceptive pain, which stems from an injury, and neuropathic pain, which is linked to damaged neural tissue, nociplastic pain occurs in the absence of tissue injury. Nonetheless, it’s thought to be associated with nervous system dysregulation — and is implicated in CSS. ^1,2

Common conditions of this nature include migraine headaches, fibromyalgia, chronic regional pain syndrome (CRPS), irritable bowel syndrome (IBS), and temporomandibular joint disorder (TMJD).^1,2

EXPLORING THE ORAL HEALTH LINK

Researchers from the University of Sydney in Australia teamed up with Viome Life Sciences in Bothell, Washington, to better understand the relationship between CSS pain and oral health. They gathered information from 156 women participants from Auckland, New Zealand.¹

The women self-reported their oral health via a World Health Organization oral health questionnaire. In addition, the researchers utilized validated measures of body pain, migraine, and abdominal pain. Salivary microbiota of the study participants was assessed via metatranscriptomic analysis.

Overall, lower oral health scores translated to higher pain scores. For instance, the study showed that women with migraines had significantly lower oral health scores than those without migraines.

PATHOGENIC ASSOCIATIONS

The researchers were able to discern the types of pathogens most associated with particular types of pain. Of the species most associated with chronic migraines, Veillonella atypica showed the strongest relationship. In addition, Mycoplasma and the relative abundance of Mycoplasma salivarium (which may be linked to TMJD pain) was markedly higher in migraine sufferers than in those without migraines.

Four species that were significantly linked to body pain as well as poor oral health include Solobacterium moorei, which is strongly associated with halitosis and promotes the coexistence of Porphyromonas and Prevotella in biofilm; Dialister pneumonsintes, a Gram-negative anaerobic periodontal pathogen linked to infections such as cerebral and neck/mediastinal abscesses; Fusobacterium nucleatum, a known Gram-negative oral pathogen; and Parvimonas micra, a Gram-positive opportunistic pathogen, recently identified as a biomarker for colorectal cancer.

Functional bowel disorder severity scores were weakly correlated with a relative abundance of 10 species. These were Fusobacterium hwasookii, F. nucleatum, Leptotrichia sp. oral taxon 212, Solobacterium moorei, Streptococcus equi, S. gallolyticus,

Streptococcus sp. LPB0220, Veillonella atypica, and V. dispar.

PATHWAYS TO PAIN

The researchers speculated that poor oral health throws the doors open to systemic circulation. They believe that this may trigger heightened pain signaling, leading to the nociplastic pain associated with CSS. The study results suggest that further research is warranted to determine whether improving oral health reduces the pain of such disorders.¹

REFERENCES

1. Erdrich S, Gelissen IC, Vuyisich M, Toma R, Harnett JE. An association between poor oral health, oral microbiota, and pain identified in New Zealand women with central sensitization disorders: a prospective clinical study. Front Pain Res (Lausanne). 2025;6:1577193.
2. Wang XJ, Ebbert JO, Gilman EA, Rosedahl JK, Ramar P, Philpot LM. Central sensitization symptom severity and patient-provider relationships in a community setting. J Prim Community Health. 2021;12:21501327211031767.