Effectiveness of a baking soda toothpaste delivering calcium and phosphate in reducing dentinal hypersensitivity.

OBJECTIVE: The purpose of this controlled clinical trial was to determine the effectiveness and safety of a single-phase dentifrice that delivers calcium, phosphate, and fluoride to the tooth surface (Arm & Hammer Enamel Care for Sensitive Teeth toothpaste, United Kingdom) in reducing dentinal hypersensitivity. METHODS: Two-hundred and eight qualifying subjects were randomly assigned to either the Enamel Care dentifrice group or a control dentifrice group, and brushed twice daily with their assigned dentifrice for eight weeks. Pain/discomfort in response to a thermal stimulus was assessed at baseline, week 4, and week 8 using a Visual Analogue Scale (VAS; primary outcome variable) and the Schiff Thermal Sensitivity Scale (STSS; secondary outcome variable). After eight weeks, volunteers from the Enamel Care group were switched to the control dentifrice and participated in a second eight-week study to determine the degree of persistence of pain reduction. RESULTS: Both groups had statistically significant VAS score reductions from baseline at weeks 4 and 8, with mean VAS scores in the Enamel Care group decreasing by 45.6% at week 4 and 61.1% at week 8 (p < 0.0001). Enamel Care was statistically significantly more effective than the control at weeks 4 and 8, with respective mean VAS reductions of 63% (p < 0.0001) and 33% (p = 0.0004) greater than the control. Consistent with the VAS score results, the Enamel Care group had respective statistically significant STSS score reductions of 77% and 58% greater than the control group (p < 0.0001). The reductions in dentinal hypersensitivity seen in the Enamel Care group at week 8 persisted for an additional eight weeks, during which the subjects discontinued use of Enamel Care and brushed with the control dentifrice. CONCLUSION: Enamel Care for Sensitive Teeth toothpaste (United Kingdom) is an effective dentifrice for the management of dentinal hypersensitivity, and its efficacy persists for a least eight weeks following discontinued product use.

Phospholipid hydrolysis and loss of membrane integrity following treatment of rat brain synaptosomes with beta-bungarotoxin, notexin, and Naja naja atra and Naja nigricollis phospholipase A2.

The effects of the phospholipase A2 (PLA2) toxins, beta-bungarotoxin and notexin, and the PLA2 enzymes from Naja naja atra and Naja nigricollis snake venoms on the plasma membrane integrity of synaptosomes were examined. Synaptosomes were isolated from rat brain cerebral cortex, corpus striatum and hippocampus. Osmotic activity, lactate dehydrogenase leakage, and leakage of 2-deoxy-D-(1-3H)-glucose-6-phosphate were monitored (37 degrees C, 10-120 min) following incubation with 0.5, 5 and 50 nM concentrations of toxins and enzymes. Damage to the synaptosomal plasma membrane was time and concentration but not tissue dependent. The potencies of the treatments were as follows: N. n. atra PLA2 greater than or equal to N. nigricollis PLA2 greater than notexin greater than beta-bungarotoxin. Chelation of Ca2+ with 5 mM EDTA completely inhibited plasma membrane disruption caused by beta-bungarotoxin and N. n. atra PLA2. One mg/ml of bovine serum albumin also blocked the disruptive action of N. n. atra PLA2, while 8 mg/ml was required to antagonize beta-bungarotoxin. A correlation between phospholipid hydrolysis and loss of membrane integrity was also observed. The generation of phospholipid hydrolytic products may be critical in the permeabilization of synaptic plasma membranes by these toxins and enzymes, however, they do not explain the presynaptic specificity and potency of beta-bungarotoxin and notexin.