The effect of nonfunctional tooth contact on sensory and pain perception in patients with myofascial pain of the jaw muscles

Abstract

PurposeThe aim of this study was to examine the effect of nonfunctional tooth contact on sensory threshold (tactile detection threshold: TDT) and pain thresholds (filament-prick pain detection threshold: FPT; pressure pain threshold: PPT) in the orofacial region of patients with myofascial pain of the jaw muscles. MethodsThe study was performed on 36 subjects: 20 normal subjects and 16 patients. Using a stair-case method, TDT and FPT were measured by Semmes–Weinstein monofilaments, on the cheek skin (CS) overlying the masseter muscles (MM) and on the skin overlying the palm side of the thenar skin (TS). PPT was measured at the central part of the MM using a pressure algometer. Each parameter was measured before and after keeping light tooth contact for 5min (session 1) and keeping the jaw relaxed for 5min (session 2) as a control. ResultsThere were significant effects of experimental condition (before–after 5min) on the TDT and FPT at several sites: after 5min, TDT was higher in all measurement sites except the left CS of the patients in session 2. As for the FPT, the reactions between CS and TS were quite opposite in both sessions: after 5min, the FPT at the CS decreased and/or remained, but the FPT at the TS increased and/or remained. Significant session effects (session 1–session 2) were only found on the FPT at the CS in patients. ConclusionSensitivity to FPT was more susceptible to tooth contact condition, especially in the patients.