Effects of Four Different Desensitizing Agents on the Dentin Permeability of Teeth: An In Vitro Study

Objectives: Dentin hypersensitivity results from external stimuli altering dentinal fluid dynamics and activating nociceptors. Although multiple desensitizing agents are available, their comparative efficacy remains debated. This study aimed to evaluate four molecules—arginine-phosphate-zinc, calcium sodium phosphosilicate, nano-hydroxyapatite, and hydroxyapatite crystals—in reducing dentin permeability after 30 days in vitro. Materials and Methods: Fifty dentin sections from intact third molars were randomly assigned to experimental or control groups. Samples were brushed twice daily with toothpaste containing one of the test agents or fluoride alone (control). Dentin permeability was measured at baseline, 7, 15, and 30 days using a liquid mass flow meter. Remineralization was assessed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Surface changes and elemental composition were analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Results: All desensitizing agents induced progressive reductions in dentin permeability. By day 15, permeability decreased by approximately 50% in all treated groups, with stabilization by day 30, except for a transient increase in one group. ATR-FTIR spectra revealed no significant changes in hydroxyapatite or organic peaks. SEM showed gradual dentinal tubule occlusion, while EDX confirmed the presence of calcium, phosphorus, oxygen, and carbon in treated samples. Conclusion: All tested agents effectively reduced dentin permeability after 30 days. These results support their clinical use and provide a basis for future randomized clinical trials to validate in vivo outcomes. Clinical Relevance: Use of toothpastes containing the tested desensitizing agents significantly reduced dentinal permeability and achieved occlusion of dentinal tubules as early as 14 days.