Abstract One hundred thirty-one patients with primary trigeminal neuralgia and 77 patients with atypical facial neuralgia or pain were treated by oral surgical procedures, with complete or almost complete pain remission in 88% of the cases and without persistent residual anesthesias, dysesthesias, or dysalgesias. The following conditions were related to patients' pain perceptions: cavities in alveolar bone at tooth extraction sites, bone fistulas, periodontal infections, and maxillary sinus infections draining into alveolar bone. The bone cavities and fistulas mentioned above were usually not visualized by standard x-ray diagnostic procedures, and their detection required a new diagnostic approach which is described. Microbiologic findings indicated involvement of a mixed, variable flora in the above conditions. Histopathologic observations of scrapings from involved bone showed a variable incidence of bone necrosis, predominantly chronic inflammatory cell populations and fibrous tissue.