Microcomputed Tomography Evaluation of Root Dentin Caries Prevention by Topical Fluorides and Potassium Iodide.

Vernon Zander,Daniel Chan,Alireza Sadr

doi:10.3390/s19040874

Abstract

The mineral content of dental hard tissues has traditionally been measured by destructive tests such as transverse microradiography. Microfocus X-ray computed tomography (micro CT) has enabled non-destructive 3D assessment of tooth demineralization. This study compared the preventive effects of silver diammine fluoride (SDF) and potassium iodide (KI) in comparison with fluoride varnish. SDF has been known to arrest caries but darkens the tooth. KI creates a precipitate with SDF that reduces the discoloration, but its effects on SDF efficacy in terms of preventing demineralization of at-risk root dentin surfaces is unknown. Bovine root dentin blocks were randomly distributed into four groups and subjected to a pretreatment in each group (n = 8); Control: deionized water (DIW); F-Varnish: 5% sodium fluoride varnish: 38% Saforide; SDF+KI: SDF followed by saturated solution of KI in DIW. The treated dentin was subjected to 8 cycles of demineralization (pH 5) for 14 h and remineralization in artificial saliva (pH 7) for 10 h. Specimens were then scanned for 12 min using micro CT at 73 KV and 1012 µA with 8.3 μm resolution. The 3D images were analyzed in Amira software to calculate lesion depth (LD), surface layer mineral density (SL) and mineral loss (ΔZ) for each specimen. One-way ANOVA with Bonferroni posthoc showed that there was a statistically significant difference between Control and all three other groups for all parameters (P < 0.001), however, there was no statistical difference among F-Varnish, SDF and SDF+KI (P > 0.05). Single application of F-Varnish, SDF and SDF+KI showed comparable preventive effects against root dentin demineralization. Application of KI did not affect anti-demineralization properties of SDF in this study. Micro CT is a quick and effective method for objective and high-resolution characterization of dentin caries lesions.

Highlights

With continuing population expansion, and the decreasing availability of dentists to provide emergency care and restorative treatment [1], there is a growing need to find a preventive and minimally invasive treatment for treating dental coronal and root caries
The surface layer mineral density was similar for all three groups, while the control showed the lowest, significantly different SL (P < 0.001)
This study showed that in terms of demineralization prevention, there was no significant effect regarding mineral density parameters when compared to silver diammine fluoride (SDF) by itself

Summary

Introduction

The decreasing availability of dentists to provide emergency care and restorative treatment [1], there is a growing need to find a preventive and minimally invasive treatment for treating dental coronal and root caries. The traditional restorative approach to treat caries can be both costly and invasive as the material and operating time increases. While several methods to treat caries exist, application of silver diammine fluoride (SDF) is one of the least invasive [2]. Other chemotherapeutic approaches have included the use of Chlorhexidine rinses, but the evidence is not conclusive as to how effective these rinses can be [3]. One application of SDF could arrest caries and is not limited by an Sensors 2019, 19, 874; doi:10.3390/s19040874 www.mdpi.com/journal/sensors

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