A Pilot Study of the Incidence and Time Course of Dentin Sensitivity Following Periodontal Surgery. L. Wolff*, L. Durkot and L. Gendreau (University of Minnesota, School of Dentistry, Minneapolis, MN 55455, USA and GlaxoSmithKline, Jersey City, NJ 07302 USA) Objective: The objective of this study was to characterize the incidence of dentinal sensitivity following periodontal surgery. Methods: A screening assessment of dentinal sensitivity was made on subjects requiring periodontal surgery. The parameters used to assess dentinal sensitivity at screening (pre-surgery), baseline (post-surgery) and over six weeks post-surgery were thermal, tactile and subjective sensitivity. A one second air blast (40-60 psi at 70 + 5° F) was used to determine thermal sensitivity, the Yeaple Probe measured tactile sensitivity and each subject rated their subjective sensitivity during daily activities. A 100 mm Visual Analog Scale (VAS) was used to obtain thermal and subjective sensitivity measurements. Tactile sensitivity scores were based on pain thresholds obtained with a Yeaple Probe. Results are based on analysis of data from 24 teeth of nine subjects. Results: The VAS score for thermal sensitivity decreased (less sensitivity) from 70.4 mm at baseline to 19.7 mm at week 6. There was a mean increase in tactile threshold scores (less sensitivity) from baseline (15.2 + 7.1 grams) to six weeks (36.1 + 18.0 grams). Mean subjective sensitivity levels based on VAS scores decreased from 77.0 (+17.9) at baseline to 15.8 (+12.9) at 6 weeks. Sensitivity levels for all three parameters returned to pre-surgery levels between weeks 4 and 6. There was a large subject variation for both tactile and subjective sensitivity score measurements. Conclusion: Thermal, tactile and subjective parameters to measure dentinal sensitivity demonstrated a mean reduction in post-surgical sensitivity over six weeks. However, thermal sensitivity measurements had less between subject variation. This study was supported by GlaxoSmithKline.