Clinical efficacy of nanohydroxyapatite-containing toothpaste at relieving dentin hypersensitivity: an 8 weeks randomized control trial

Abstract

Objective: The objective of this study was to investigate and compare the effectiveness of several toothpastes containing nanohydroxyapatite (nano-HAP) to relieve dentin hypersensitivity (DHS) with that of a commercial desensitizing dentifrice containing calcium sodium phosphosilicate (CSPS).

Materials and methods: In this double-blind, randomized, parallel-group clinical trial, patients diagnosed with DHS and qualified to participate were randomized into four groups: toothpaste containing 10% nano-HAP (10%nano-HAP), 15% nano-HAP (15%nano-HAP), 10% nano-HAP supplemented with potassium nitrate (KNO₃) (10%nano-HAPKN), or CSPS. Subjects' baseline and post-treatment sensitivities were assessed using visual analog scale (VAS) after the application of ice-cold and air stimuli. Subjects used their assigned toothpaste for routine toothbrushing twice daily. Post-treatment sensitivity was assessed every 2 or 8 weeks. Mean change in VAS (mm) from baseline at each time point were compared using random-intercept, mixed-model analysis and Duncan test (P < 0.05).

Results: With either air or cold stimulus, VAS indicated a significant (P < 0.001) reduction from baseline DHS at each time point with all test toothpastes. Among the nano-HAP toothpastes, 15%nano-HAP and 10%nano-HAPKN were consistent in DHS reduction with both stimuli. With either stimuli, the CSPS did not significantly differ from 15%nano-HAP and 10%nano-HAPKN at any time point.

Conclusions: Toothpaste containing nano-HAP (10 or 15%) alone or supplemented with KNO₃ was as effective as CSPS for relief of DHS symptoms when used at least twice daily.

Fig. 1. Patient flow diagram.

CSPS calcium sodium phosphosilicate.

Fig. 2. Reduction in DHS over time measured with VAS after a cold stimulus.

For each product, there was a significant (P < 0.001) reduction in DHS at each time point. Comparing the reduction of DHS among the products, the following product pairs differed significantly (P < 0.001) from each other at the indicated measurement time period. Week 2: 10%nano-HAPKN and 10%nano-HAP; week 4: 10%nano-HAPKN and 10%nano-HAP; week 6: 10%nano-HAPKN and 10%nano-HAP, 15%nano-HAP and 10%nano-HAP, CSPS and 10%nano-HAP; and week 8: CSPS and 10%nano-HAP. CSPS calcium sodium phosphosilicate.

Fig. 3. Reduction in DHS over time measured with VAS after evaporative air stimulus.

For each product, there was a significant (P < 0.001) reduction in DHS at each time point. Comparing the reduction of DHS among the products, the following product pairs differed significantly (P < 0.001) from each other at the indicated measurement time period. Week 2: no significant difference among the products. Week 4: 10%nano-HAPKN and 10%nano-HAP; week 6: 10%nano-HAPKN and 10%nano-HAP, 10%nano-HAPKN and 15%nano-HAP; week 8: 10%nano-HAPKN and 10%nano-HAP, CSPS and 10%nano-HAP. CSPS calcium sodium phosphosilicate.