Clinical Evaluation of A 5% Potassium Nitrate Containing Mouthrinse in Relieving Dentine Hypersensitivity (DH)

Potassium nitrate dentifrices (KNO3) have been used to treat the symptoms of dentine hypersensitivity (DH), however relatively few mouthrinse studies have been published. Aim The aim of this study was to compare a 5% KNO3 mouthrinse to a placebo control in an 8-week double-blind placebo-controlled study. Materials and Methods Male and female subjects aged 18 to 65 years in good health and a history of Dentine Hypersensitivity were recruited for the study. Subjects were randomised and allocated into the test and control groups and instructed to use the mouthrinse twice a day after brushing with a regular family toothpaste using a small head soft toothbrush. The clinical evaluation of Dentine Hypersensitivity included 1) Subjective Sensitivity (Perception of overal sensitivity) using aVAS score, 2) Thermal Sensitivity response from a one second air blast from a dental air syringe using VAS Scores, 3) Tactile Sensitivity Threshold Scores on the selected test teeth using a controlled force probe (gm. weight) and 4) Tactile Sensitivity at a Fixed Force of 40 gm. weight evaluating the remaining teeth to determine the existence of dentine sensitivity based on a simple yes/no response. Subjects were evaluated at baseline, four and eight weeks. Results The 104 subjects recruited for the study, 103 subjects (35M; 68F mean age 34.6 years) completed the study. The results indicated that the tactile response demonstrated the clearest difference between the KNO3 mouth rinse and placebo. Both the KNO3 and placebo mouth rinse showed an increase in the tactile sensitivity threshold (i.e. less sensitivity) at both evaluation time points with the increase in the tactile sensitivity threshold twice as high at Week 8 than at Week 4. The increase in sensitivity threshold using KNO3 was twice as large as the increase with Placebo at both time points (6.79 g for KNO3 compared to 3.60g for Placebo at Week 4 and 11.80 g for KNO3 compared to 6.58 g for Placebo at Week 8) with a statistically significant difference (p = 0.031) at Week 8. Moreover, the efficacy of the KNO3 treatment was more apparent in subjects with a more severe condition of dentine hypersensitivity, as measured by the number of threshold sensitive teeth at baseline. Among the 75 subjects with ≥ three tactile sensitive teeth, the active treatment was statistically significantly superior to placebo (p < 0.01) at both the Week 4 and Week 8 evaluation points. Conclusion These results therefore confirm the results of Gillam et al. (1996) by demonstrating that a 5% KNO3 mouthwash significantly reduced dentine hypersensitivity as measured by tactile stimulation.This study was originally supported by Block Drug Company Inc., Jersey City, NJ. USA now GlaxoSmithKline. Drs. F. Ley, A. Swern, M. Friedman and FA Curro were employees of Block Drug Co, Inc, NJ, USA

Interaction between alpha adrenergic and serotonergic activation of canine saphenous veins

Serotonin and norepinephrine produced concentration-dependent contractions of helical strips of canine saphenous veins. The contractile responses to both agonists were inhibited by the alpha adrenergic receptor blocking agent phentolamine. Tolazoline inhibited the contractile responses of canine saphenous veins to norepinephrine but augmented those to serotonin. Blockade of adrenergic neuronal reuptake with cocaine enhanced the sensitivity of the canine saphenous vein to serotonin, but did not suppress the inhibition by phentolamine of the contractile responses to this indolealkylamine. Serotonin-mediated venoconstriction was not secondary to release of norepinephrine since it was not accompanied by an increased release of [7-3H]-norepinephrine. These findings suggest that serotonin does not contract canine saphenous veins by stimulation of typical serotonergic receptors. The binding sites for serotonin and norepinephrine in cutaneous venous smooth muscle may share part of a common receptor complex, which triggers the contractile process. Alternatively, serotonin and norepinephrine may act at two different receptors to elicit contraction of canine saphenous veins.link_to_subscribed_fulltex