Effect of topical lidocaine in the oral and facial regions on tactile sensory and pain thresholds.

OBJECTIVE: The aim of the present study was to examine the effect of lidocaine application to the face, tongue and hand on sensory and pain thresholds of symptom-free subjects.

DESIGN: Eighteen females (mean age 25.7 years, range 22-38) participated. Using Semmes-Weinstein monofilaments, the tactile detection threshold (TDT) and the filament-prick pain detection threshold (FPT) were measured on the cheek skin (CS), tongue tip (TT) and palm side of the thenar skin (TS). Subjects were tested in 2 sessions at a 1week interval in randomised order. Lidocaine (session A) or placebo gel (session B) was applied for 5min. The TDT and FPT were measured before and after application.

RESULTS: The TDT at all sites in session A significantly increased after 5min, but a significant session effect on the TDT was only found at the TT (P<0.01). On the other hand, there were significant session effects on the FPT at all sites (P<0.01).

CONCLUSION: These results indicate that the pain threshold (FPT) is more susceptible to local anesthetics than the sensory threshold (TDT), but further study is needed to use topical lidocaine for the control of oral and facial pain in the clinic.