The effect of stannous fluoride desensitizing toothpaste on immediate dentin sealing ability of universal adhesive in vitro

Abstract

Background/purpose: The stannous fluoride pretreatment of dentin may compromise the bond formation of the dentinal adhesive system. This study aimed to determine the effect of stannous fluoride (SnF₂) desensitizing toothpaste on immediate dentin sealing ability (IDS) of universal adhesive in human intact dentin using dentin permeability test and scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS).

Materials and methods: Sixty sound dentin specimens were prepared from 60 extracted intact third molars, then treated with 17 % EDTA for 60 s to simulate hypersensitive dentin, and randomly divided into 2 series. Series 1 (dentin permeability test; n = 40) had 4 different treatment groups: (1) universal adhesive (self-etch mode), (2) universal adhesive (total-etch mode), (3) SnF₂ pretreatment + universal adhesive (self-etch), (4) SnF₂ pretreatment + universal adhesive (total-etch). The IDS of each group was the percentage decrease of hydraulic conductance of dentin after bonding. Series 2 (n = 20) was SEM-EDS analysis of different treated dentin before bonding. The data were analyzed using 2-way ANOVA and Tukey test.

Results: In groups of no SnF₂ pretreatment, the IDS of universal adhesive were 79.53 ± 20.71 and 77.34 ± 18.14 % for self-etch and total-etch mode, respectively. In groups of SnF₂ pretreatment, the corresponding values were 71.54 ± 15.56 and 69.56 ± 9.92 %, respectively. Although SnF₂ pretreated-dentin had the remarkable signals of silicon and tin, there were no significant reductions in the IDS of universal adhesive (P < 0.05).

Conclusion: SnF₂ desensitizing toothpaste has no adverse effect on the immediate dentin sealing ability of universal adhesive.

Keywords: Dentin hypersensitivity; Human dentin; Sealing ability; Stannous fluoride; Universal adhesive.

Figure 1

Flowchart of the experimental design.

Figure 2

Mean (±1 SD) percentage of immediate dentin sealing ability of bonded dentin using universal adhesive with self-etch or total-etch mode and without (black column) or with (gray column) stannous fluoride toothpaste pretreatment. NS represents no significant difference among the groups (P > 0.05).

Figure 3

(A–D) Scanning electron micrographs of human dentin (original magnification X3000). (A) EDTA treated dentin; (B) EDTA+35 % phosphoric acid treated dentin; (C) EDTA + SnF₂ toothpaste treated dentin, blue arrows showing occlusions of dentinal tubules; (D) EDTA + SnF₂ toothpaste+35 % phosphoric acid treated dentin, yellow arrows showing fine particles still remained on the dentin surface.

Figure 4

Energy-dispersive X-ray spectroscopy (EDS) spectra taken from the treated dentin surface of (A) 17 % EDTA treatment, (B) 17 % EDTA+35 % phosphoric acid treatment, (C) 17 % EDTA + SnF₂ toothpaste treatment, (D) 17 % EDTA + SnF₂ toothpaste+35 % phosphoric acid treatment with the right table for the weight and atomic percentage of the following elements: C–carbon, N–nitrogen, O–oxygen, F–fluoride, Si–silicon, Ca–calcium, P–phosphorous, Zn–zinc, Sn–Tin.