To compare the clinical effect over 3 months of two commercially available desensitizing agents on the level of discomfort of patients with complaints of dentin sensitivity.An oxalate-containing pre-polymerized resin suspension (Pain-Free), a 0.7% fluoride solution (DentinBloc), and a distilled water placebo were compared in a clinical setting. Ten volunteer patients exhibiting three or more teeth that were sensitive to touch and to a stream of forced air were enrolled in the study (52 teeth total). Each patient's level of sensitivity to tactile stimuli and to a forced air stream was recorded using a visual analog scale (VAS). The tactile stimulus was a metal probe rubbed across the exposed dentin with a constant pressure of 40 grams. A 1-second blast of air from a dental unit air syringe was used to generate the air stream. The desensitizing agents were applied according to manufacturers' guidelines. Sensitivity measurements were recorded at baseline, immediately after treatment, at 1 week, 1 month, and at 3 months. VAS pain scores were analyzed using a repeated measures ANOVA (alpha = 0.05).The pre-polymerized resin suspension (Pain-Free), the fluoride-containing solution (DentinBloc), and the placebo all decreased dentin sensitivity. No significant difference was found among the desensitizing agents at any time period (P > 0.05).