A novel potassium oxalate-containing tooth-desensitising mouthrinse: a comparative in vitro study.

OBJECTIVE: To compare the efficacy of a new potassium oxalate (KO)-containing mouthrinse [Listerine® Advanced Defence Sensitive (LADS)] in reducing dentine permeability and occluding open dentinal tubules versus other desensitising products.

METHODS: The permeability of acid-etched dentine disks was measured by hydraulic conductance; dentine surfaces were examined by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The KO concentration was optimised for tubule occlusion by screening formulations containing 0.0-2.0% KO (n=5 disks per concentration). The optimal formulation was compared with five commercial products with non-oxalate occlusion technologies. After establishing the baseline permeability of acid-etched dentine disks, disks (n=6 per product) were randomly treated with the desensitising products (12 treatments, each 60 s, alternated with distilled-water rinses) and permeability was measured at intervals. Occluded disks were acid challenged. All experiments were conducted at room temperature. An unpooled, two-tailed t test was performed to assess between-treatment differences in relative residual permeability.

RESULTS: The optimal concentration of KO in LADS was 1.4%, which provided ≈ 100% reduction in dentine permeability after nine treatments. Only LADS reduced permeability to zero and was significantly more effective in reducing dentine permeability than the other products (p ≤ 0.033 vs all other test products). All products partially occluded dentine. The occlusion associated with LADS was substantially more stable in resisting acid challenge versus Colgate® Sensitive Pro-Relief mouthrinse (p=0.054) and significantly more stable versus all other test products (p ≤ 0.045), as determined by dentine permeability.

CONCLUSION: LADS was significantly more effective in occluding open dentinal tubules versus other desensitising products.

CLINICAL SIGNIFICANCE: LADS provides fast, complete and stable intratubular occlusion of patent dentinal tubules.