Does potassium iodide after SDF reduce staining without reducing caries arrest?

1. Introduction

A concern to consider regarding SDF is the black staining of the arrested carious lesions, which may result in undesirable aesthetics [14]. Despite this concern, most parents preferred this option to advanced treatment methods such as general anesthesia [15]. Applying a saturated solution of potassium iodide (KI) immediately after silver diamine fluoride application has been claimed to minimize the staining of dentin caries [16]. This is probably due to the reaction of iodide ions from the KI solution with the excess silver ions from the silver diamine fluoride solution, which forms a precipitate of silver iodide. Moreover, it was shown that dentine permeability could be reduced if potassium iodide was applied after a fluoride-containing silver diamine solution, consequently reducing dentin hypersensitivity [17]. Hamama [18] and Koizumi [19] showed positive results regarding the desensitizing and caries-arresting effect using a combined silver diamine fluoride and potassium iodide agent (38% SDF+KI; Riva Star®). However, caries arrest was reported to be poorer when potassium iodide was combined with silver diamine fluoride solution in children with caries lesions with an ICDAS score of 3 or above. On the other hand, the combination had better odds of minimizing the staining effect than solely applying silver diamine fluoride [20].

Efficacy of Different Fluoride Therapies on Hypersensitive Carious Lesions in Primary Teeth. © 2023 by the authors. Creative Commons Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/).

DISCUSSIONS

Lastly, SDF causes carious lesions to turn black, due to the formation of silver oxide. If these lesions are left untreated, the staining has been shown to be irreversible. SDF provides a treatment option for carious lesions through biological and chemical means, unlike a number of other minimally invasive treatment strategies which solely rely on a chemical mode of action. In this respect, Crystal et al. (2017) assessed the parental perceptions of staining caused by the SDF. The results showed staining was deemed to be acceptable on the posterior teeth in comparison to the anterior region. The use of potassium iodide (KI) immediately after the application of silver diamine fluoride has been shown to potentially improve the staining of carious lesions in dentine or the surrounding enamel (Patel et al., 2018). Vinh et al. (2017) also reported the use of KI immediately after applying SDF showed minimal or no staining after a period of 4 weeks in comparison to the SDF application alone.

A systematic review on the effect of silver diamine fluoride for management of dental caries in permanent teeth. © 2023 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd. Creative Commons Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/).

Abstract

OBJECTIVES: To investigate the effectiveness of silver diammine fluoride (SDF) solution application in arresting dental root caries and to assess the color of arrested caries lesions. METHODS: This study was conducted in elderly centers in Hong Kong. A total of 83 elders with 157 root surfaces with active caries lesion were randomly allocated into 3 groups: Gp1 (placebo control)-annual application of soda water; Gp2-annual application of SDF solution; Gp3-annual application of SDF solution immediately followed by potassium iodide (KI) solution. Color of the arrested root caries lesion was assessed with reference to PANTONE color plates and classified into one of the followings: yellow (7401U); light brown (1245U); dark brown (4635U); and black (Black U). Status of root surfaces was assessed every 6 months by the same independent examiner. RESULTS: After 30 months, 100 (64%) of the included root caries lesions were reviewed. The arrest rates of root caries were 45%, 90%, and 93% in Gp1 (control), Gp2 (SDF) and Gp3 (SDF/KI), respectively (&#x3c7;(2) test, p<0.001). Pairwise comparisons showed elders in the control group had a lower proportion of the active root caries changed to arrested (p<0.001) and the proportions of root caries being arrested in the SDF and SDF/KI groups were not significantly different (p>0.05). The distributions of arrested caries lesions by color were not significantly different between the SDF and SDF/KI groups (&#x3c7;(2) test, p>0.05). CONCLUSIONS: Application of SDF solution, with or without application of KI afterwards, is effective in arresting root caries among elders in a water fluoridated area. In the long term, blackening of arrested root caries is not reduced by immediate application of KI after the application of SDF. CLINICAL SIGNIFICANCE: In a water fluoridated area, annual application of SDF solution or SDF/KI solution can arrest dental root caries in elders. In the long term, application of KI does not reduce the blackening of arrested caries lesions caused by SDF.