Effectiveness of Thymoquinone and Fluoridated Bioactive Glass/Nano-Oxide Contained Dentifrices on Abrasion and Dentine Tubules Occlusion: An Ex Vivo Study

Abstract

Objectives: Dentin hypersensitivity (DH) is mainly due to the loss and replenishment of minerals from tooth structure, where the lost minerals can be rehabilitated with a biomimetic approach. The objectives were to determine the relative dentin abrasivity (RDA) of experimental (EXT) dentifrices and to determine the efficacy to occlude dentinal tubules.

Materials and methods: Experimental dentifrices contained nano-fluoridated bioactive glass (n-FBG: 1.5 wt.% [EXT-A], 2.5 wt.% [EXT-B], and 3.5 wt.% [EXT-C]), nano-zinc oxide (n-ZnO), and thymoquinone as active agents. Bovine dentin blocks were subjected to brushing treatments as per groups, that is, distilled water; commercial dentifrice (control, CT); EXT toothpastes; and EXT-D without active agents. Samples were tested for three-dimensional (3D) abrasion analysis according to ISO-11609:2010 (International Organization for Standardization [ISO]). The roughness average (Ra), RDA, surface topography, and elemental compositions were investigated.

Statistical analysis: One-way analysis of variance (ANOVA) with post-hoc Tukey's and Tamhane's test was performed for characterizations using Statistical Package for the Social Sciences (SPSS) version 21. The result was considered significant with p-value ≤ 0.05.

Results: Comparisons of Ra differed significantly between all groups with p < 0.05 except CT and EXT-A. The RDA values of EXT-A, EXT-B, and EXT-C were calculated as 74.04, 84.26, and 116.24, respectively, which were well within the acceptable limit set by international standards. All n-FBG containing dentifrices demonstrated uniform occlusion of dentinal tubules; however, highly concentrated EXT dentifrices showed more occlusion.

Conclusions: Acceptable range of RDA and superior occlusion of tubules by novel dentifrices suggest that it may be recommended for treating DH.

Conflict of interest statement

None declared.

Figures

Fig. 1

(A) Mean plot of difference—roughness average (Ra) with 95% confidence interval, and (B) relative dentin abrasivity (RDA) of experimental and control dentifrices (CT).

Fig. 2

Comparison of three-dimensional (3D) images of surface topography of different groups by atomic force microscopy (AFM): (A) distilled water, (B) control dentifrice (CT), (C) EXT-A, (D) EXT-B, (E) EXT-C, (F) EXT-D, and (G) untreated portion.

Fig. 3

(A) Scanning electron microscopy (SEM) micrograph of dentin surface morphology etched with 37% phosphoric acid showing open or patent dentinal tubules, (B–G) SEM micrographs of all six groups at magnifications ×10,000 after rinsing and sonication, (B) distilled water, (C) control dentifrice (CT), (D) EXT-A, (E) EXT-B, (F) EXT-C, and (G) EXT-D.

Fig. 4

Scanning electron microscopy (SEM) micrographs of all six groups at magnifications ×10,000 after rinsing with distilled water only. (A) Distilled water, (B) control dentifrice (CT), (C) EXT-A, (D) EXT-B, (E) EXT-C, and (F) EXT-D.

Fig. 5

Energy dispersive X-ray (EDX) of samples treated with nano-sized fluoride-containing bioactive particles (n-FBG) and nano-oxides (n-ZnO) showing point scan elemental analysis and attachment selection of particles attached to the samples in groups with experimental toothpaste slurries: (A) EXT-A, (B) EXT-B, and (C) EXT-C.