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Real-Time Assessment of Dentinal Fluid Flow Reduction by Desensitising Agents Using Subnanolitre Flow Measuring
Soyeon Kim1, Satoshi Yamaguchi2, In-Bog Lee3
1Department of Oral Anatomy and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
Objective:
This study aimed to evaluate and compare the dentinal tubule-occluding efficacy of various desensitising toothpastes and a sodium fluoride varnish using a subnanolitre scaled fluid flow measuring device (NFMD).
Methods:
Bovine dentin specimens were treated with four desensitising toothpastes (Colgate, Median, Bamboo Salt, and Sensodyne), a 2.1% sodium fluoride professionally-deliverable varnish (Clinpro), and distilled water (DW). Real-time dentinal fluid flow (DFF) was measured under simulated pulpal pressure (32 cm H₂O) for 1000 seconds using the NFMD system. Each toothpaste was applied directly to assess its chemical occlusion capability, with measurements recorded before, during, and after material removal. Surface morphology and the extent of tubule occlusion were examined using field-emission scanning electron microscopy (FE-SEM) in both cross-sectional and surface views. Data were analysed by one-way analysis of variance.
Results:
A significant overall treatment effect was observed (P < .001). Bamboo Salt, Sensodyne, and Colgate showed greater mean reductions than Clinpro, whereas Median did not outperform the DW group. SEM findings supported these trends, revealing substantial tubule occlusion for Bamboo Salt and Sensodyne and minimal occlusion for Median and DW.
Conclusion:
Desensitising toothpastes reduced dentinal permeability to levels comparable to a sodium fluoride varnish. Real-time fluid flow measurement using NFMD enabled functional validation of dentinal tubule occlusion beyond surface morphology.
Clinical Relevance:
Commonly available desensitising toothpastes can provide meaningful reductions in dentinal permeability. Understanding how different formulations interact with exposed dentin may help guide product selection based on a patient's specific needs. Real-time assessments of dentinal fluid movement may also assist in evaluating emerging desensitising technologies.
