Mechanisms Underlying Burning Mouth Syndrome and Occlusal Dysesthesia: Shared and Distinct Pathways of Oral Sensory Dysregulation.

backgroundBurning mouth syndrome (BMS) and occlusal dysesthesia (OD) are chronic oral sensory disorders that present without evident local pathology yet frequently cause substantial diagnostic and therapeutic challenges in oral medicine practice. Although both conditions may clinically overlap, their mechanistic relationship remains poorly understood.

objectiveTo compare the pathophysiological mechanisms of BMS and OD, examine their potential overlap, and propose a hypothesis-generating conceptual framework of oral sensory dysregulation.

methodsRelevant literature was identified through searches of PubMed, Scopus, and Google Scholar using combinations of the terms "burning mouth syndrome," "occlusal dysesthesia," "phantom bite syndrome," "central sensitization," and "small fibre neuropathy." Additional studies were identified through manual review of reference lists. Priority was given to clinically and mechanistically relevant neuroimaging, psychophysical, and pharmacological studies. This review was conducted as a narrative synthesis rather than a systematic review.

resultsCurrent evidence suggests that BMS involves trigeminal small-fibre dysfunction with subsequent central nociceptive amplification, whereas OD predominantly reflects maladaptive central processing of otherwise intact periodontal mechanoreceptive input. Despite these mechanistic differences, both conditions demonstrate overlapping features including affective comorbidity, sensory hypervigilance, altered prefrontal and frontostriatal involvement, and responsiveness to centrally acting pharmacological agents. Clinical overlap between BMS and OD has also been reported, particularly in treatment-refractory presentations.

conclusionBMS and OD may represent distinct but partially overlapping phenotypes within a broader framework of oral sensory dysregulation. Recognition of shared and divergent mechanisms may improve differential diagnosis, support mechanism-informed pharmacological management, and guide future hypothesis-driven research in oral medicine.