Immediate Sensitivity Effects with 1.5% Oxalate Strips: Inclusive Clinical Meta-Analysis

Objectives: This research systematically evaluated immediate post-treatment response of oxalate gel strips on dentinal hypersensitivity.
Methods: An inclusive meta-analysis was conducted of clinical trials using oxalate gel strips with immediate post-treatment sensitivity measurements. The sample consisted of 7 clinical trials at 4 sites, each of which tested 1.5% oxalate gel strips (Crest® Sensi-Stop™Strips, The Procter & Gamble Co.) dispensed in blinded packaging for 10 minutes use. While the trials used various controls, methods and examiners, sensitivity was always measured after direct test site stimulation. Three stimuli were used: evaporative (1-sec cool air), thermal (2^oC water) and tactile (10-50 gm). Depending on design, stimulated sensitivity was graded before/after strip use by clinical examiners using a standard 4-point scale (Schiff), pressure tolerability was measured (Yeaple probe), and subjects reported pain using visual analog scales. Response was investigated using a general linear mixed model, with baseline sensitivity as a fixed covariate and study as a random effect, and adjusted means were calculated with 2-sided comparisons at 0.05 significance levels.
Results: The pooled sample included 222 subjects (18-71 years) who used 1.5% oxalate strips for 10 minutes, and had immediate post-treatment sensitivity assessed. By stimulus type, the pooled sample included 176 subjects measured using air, 68 with water, and 74 with tactile stimuli. There was considerable diversity in sensitivity at baseline. Treatment relief was evident for a majority of subjects, with mean improvements of 24-35% for air, 29-55% for water, and a near doubling of tactile tolerability. All stimulus/method combinations showed highly significant (p<0.005) improvements immediately after strip removal. Except for examiner-graded water response, study effects were very low, contributing <7% of between-study variations.
Conclusions: An inclusive meta-analysis (all studies and subjects) provides robust and consistent evidence of immediate sensitivity relief with the first use of 1.5% oxalate gel strips.