Occlusion of Dentinal Tubules by Nanohydroxyapatite and Zinc Carbonate Hydroxyapatite-Based Toothpastes as Desensitizing Agents: An in Vitro Study

Objectives: Dentin hypersensitivity (DH), characterized by a short, sharp, and intense pain response to a stimulus, is the most commonly encountered patient complaint. Various in-office and at-home methods including the recently introduced nano-hydroxyapatite (n-HA) and zinc carbonate-hydroxyapatite (Zn-CHA)-based products reduce the DH discomfort. This study compared the effectiveness of commercially available n-HA and Zn-CHA toothpastes for occlusion of dentinal tubules for management of DH. Materials and Methods: In this in vitro study, 40 tooth samples were randomly assigned to 4 groups (n=10): negative control): brushing without toothpaste,Aclaim n-HA toothpaste,Biorepair Zn-CHA toothpaste, andShyNM calcium sodium phosphosilicate (CSPS) toothpaste. After demineralization with 17% ethylenediaminetetraacetic acid, the mounted specimens were brushed with an electric pressure-sensitive toothbrush and the respective toothpaste. Occlusion of dentinal tubules was subsequently evaluated under a scanning electron microscope (SEM). Elemental composition of the occluding plug was analyzed by energy-dispersive X-ray spectroscopy (EDX). Results: The test n-HA and Zn-CHAand the positive control (CSPS) groups revealed significantly higher tubular occlusion compared to the negative control group (p= 0.001). The highest tubular occlusion was achieved in n-HA and Zn-CHA groups (80%); while negative control showed no occlusion (0%). Elemental analysis of dentinal plug showed significant differences in carbon, oxygen, calcium, and phosphorus levels among the groups (p