|Year : 2018 | Volume
| Issue : 3 | Page : 257-261
Effect of fluoridated varnish and silver diamine fluoride on enamel demineralization resistance in primary dentition
Najmeh Mohammadi1, Mohammad Hossein Farahmand Far2
1 Department of Pediatric Dentistry, Oral and Dental Disease Research Center, School of Dentistry, Shiraz University of Medical Science, Shiraz, Iran
2 Oral and Dental Disease Research Center, School of Dentistry, Shiraz University of Medical Science, Shiraz, Iran
|Date of Web Publication||24-Sep-2018|
Dr. Najmeh Mohammadi
Ghasrodasht Street, Ghom Abad Avenue, Shiraz Dental School, Shiraz
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: International data on caries epidemiology confirm that dental caries remains a significant disease of childhood in both developing and developed countries. Based on preventive dentistry, topical fluoride may be a useful measure to arrest caries lesions. Fluoride used in various forms have been proven to be effective in dental caries prevention. Aim: This study aims to compare the effect of fluoridated varnish and silver diamine fluoride (SDF) solution on primary teeth enamel resistance to demineralization. Methods: Forty-five caries-free deciduous canine teeth extracted due to orthodontic reasons, devoid of any defects were selected. Teeth were mounted on acrylic blocks as their buccal surface was exposed and baseline surface microhardness (SMH) determination was accomplished. Enamel samples were randomly distributed into three groups with 15 specimens each. One group was used as control (distilled and deionized water) (C); in the other groups, either a fluoridated varnish (V) or an SDF solution was applied to the enamel blocks. The blocks of each group were submitted to pH-cycling solutions and treatment regimen. After pH-cycling process, SMH determination was done again for all samples. Results: According to the present findings, the percentage of decrease in SMH of control group is numerically greater than other groups and also SDF group shows the most resistance against mineral loss. However, based on one-way ANOVA test, this difference is not statistically significant (P = 0.217). Conclusion: SDF solution and fluoride varnish display similar effectiveness in preventing the demineralization of deciduous anterior teeth, and no significant difference was observed.
Keywords: Enamel demineralization, fluoride varnish, primary teeth, silver diamine fluoride
|How to cite this article:|
Mohammadi N, Farahmand Far MH. Effect of fluoridated varnish and silver diamine fluoride on enamel demineralization resistance in primary dentition. J Indian Soc Pedod Prev Dent 2018;36:257-61
|How to cite this URL:|
Mohammadi N, Farahmand Far MH. Effect of fluoridated varnish and silver diamine fluoride on enamel demineralization resistance in primary dentition. J Indian Soc Pedod Prev Dent [serial online] 2018 [cited 2021 May 8];36:257-61. Available from: https://www.jisppd.com/text.asp?2018/36/3/257/241971
| Introduction|| |
Dental caries is one of the most common chronic dental diseases in all countries and all populations with varying degree of severity. International data on caries epidemiology confirm that dental caries remains a significant disease of childhood in both developing and developed countries. Treatment of dental caries, especially in children may require advanced skills of clinicians and sometimes high cost of general anesthesia for patient management.
Based on preventive dentistry, use of topical fluoride may be a useful measure to arrest caries lesions because fluoride used in various forms have been proven to be effective in dental caries prevention.
Due to the characteristics of deciduous teeth enamel (half as thick as that of permanent teeth, lower mineral content and higher organic content, and more susceptibility to caries), use of fluoride to control the development and progression of carious lesions is so important in primary dentition. Topical application of fluoride has been proven to be the most important method in combating carious lesions.,,,
High-concentration topical fluoride agents, such as 5% sodium fluoride (NaF) varnish containing 22,600 ppm fluoride have been used to arrest caries. Although encouraging results have reported in clinical trials using topical NaF solution or NaF varnish,,,, other newer products also have been introduced.
One of the newest fluoride products is silver diamine fluoride (SDF). SDF 38% solution containing 44,800 ppm fluoride have been used to arrest caries. Chu et al. in a clinical trials showed that SDF prevented and arrested coronal caries in primary teeth in preschool children and in root surface of permanent teeth in adult. The mechanism of action of SDF is hypothesized to be its anticariogenic properties,, ability to increase enamel surface microhardness (SMH), and reduce enamel surface mineral loss., Laboratory studies have also found that SDF has an intense antibacterial effect on cariogenic biofilm and hinders caries progression.,,
In dentistry, different pH-cycling models have been developed to evaluate the fluoride effect in either reducing enamel demineralization or enhancing remineralization. These approaches have been used with tremendous success in cariology.
In infants, both fluoridated varnish and SDF have been indicated and used due to their easy application and safety. However, comparison between these two fluoride agents on enamel resistance to demineralization process has not been clearly established. Thus, the aim of this investigation is to study the effect of the application of a fluoridated varnish or SDF solution on enamel microhardness and resistance to demineralization in an in vitro cariogenic challenge by pH-cycling method.
| Methods|| |
The caries-free anterior deciduous teeth, devoid of stains or any other defects visible under a stereoscopic magnifying glass were selected. The teeth were collected from patients who needed primary teeth extraction due to orthodontic reasons after informed consent. Teeth were immersed in 1% thymol and stored in a refrigerator until their use. After cutting the roots with diamond disks, teeth were mounted on acrylic blocks as their buccal surface was exposed and enamel blocks (4 mm × 4 mm) were obtained. The enamel surface was polished and then baseline SMH determination was accomplished using a Future-Tech FM-ARS microhardness tester (Future-Tech Corp., Tokyo, Japan) with a Knoop diamond under 25-g load for 5 s. Five indentations were made at the center of the enamel surface. The objectives of baseline SMH determination was to select the blocks with the same SMH range and calculate the SMH change that occurs after pH-cycling. Enamel samples were randomly distributed into three groups with 15 specimens each. One group was used as control (distilled and deionized water) (C); in the other groups, either a fluoridated varnish (V) or a SDF solution (SDF) was applied to the enamel blocks. The blocks of each group were submitted to pH-cycling solutions. After pH-cycling process, SMH determination was done again for all samples.
Treatments and pH-cycling
A thin layer of fluoridated varnish (Duraphat 2.26% F-pH 7.0, Woelm and Pharma Co., Eschwege, Germany) was applied with a brush to the enamel blocks of the “V” group. After 24 h, the varnish was removed carefully with a surgical blade. Removal was completed with cotton swabs soaked in acetone. Then, the blocks were washed with deionized water for 1 min. SDF ((38% w/v) (Saforide solution [J Morita Company, JAPAN]) was applied with a cotton swab to the enamel blocks of the SDF group for 2 min. After application, the blocks were washed with a flow of deionized water for approximately 30 s and lightly dried with absorbent paper.
The blocks from each group were submitted to a pH-cycling model simulating a high caries challenge for 7 days, basically according to Vieira et al. The blocks were kept in demineralizing solution (2.0 mmol/L calcium, 2.0 mmol/L phosphate in 0.075 mol/L acetate buffer, and 0.02 μm F/mL, pH 4.7) for 3 h (35.5 mL per block), and in a remineralizing solution (1.5 mmol/L calcium, 0.9 mmol/L phosphate, 150 mmol/L KCl in 0.1 mol/L Tris buffer, and 0.03 mm F/mL, pH 7.0) for 21 h (17.75 mL per block). The de- and remineralizing solutions were changed daily to prevent depletion or saturation of the solution and accumulation of enamel dissolution products. The cycle was repeated daily for 5 days and the enamel blocks remained in the remineralizing solution for 2 days until the analysis.
After pH-cycling, SMH of the blocks from the C, V, and SDF groups measured again (SMH1). Five indentations spaced 100 μm from each other in relation to the baseline were made using the microhardness tester Shimadzu HMV-2000 (Shimadzu Corporation, Kyoto, Japan). The percentage loss of SMH (%SML) calculated (%SML = [(SMH1 – SMH)/SMH] × 100). The results were analyzed with SPSS package, version 20 (SPSS Inc., Chicago, IL, USA).
| Results|| |
Mean values of enamel SMH for all three groups: control (C), sodium fluoride varnish (V), and SDF before and after the pH-cycling process have been presented in [Table 1].
|Table 1: Mean values of enamel surface microhardness before and after pH-cycling process|
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In this study, no statistically significant difference was observed between the control, sodium fluoride varnish, and SDF groups before the pH recycling process (P = 0.217). Hence, the data were confirmed to be homogenous.
After pH-cycling process, analysis of data by Paired t-test showed that the decrease of microhardness was statistically significant in all three groups of the study (P = 0.00).
The percentage loss of SMH (%SML) calculated for all groups (%SML = [(SMH1 – SMH)/SMH] x 100) and is shown in [Table 2] and [Figure 1]. [Figure 2] shows the mean values of enamel surface microhardness before and after pH-cycling process and percentage of microhardness loss for all groups of the study.
|Figure 2: Mean values of enamel surface microhardness before and after pH-cycling process and percentage of microhardness loss for all groups|
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According to the present findings, the percentage of decrease in SMH of control group is numerically greater than other groups and SDF group shows the most resistance against mineral loss. However, based on one-way ANOVA analysis, this difference is not statistically significant (P = 0.219).
| Discussion|| |
The aim of the present study was to compare the effect of two fluoride therapy products on primary teeth enamel resistance to demineralization using pH-cycling method.
Measuring the surface characteristics of teeth by means of microhardness test is a common method for studying enamel surface changes after remineralization and demineralization cycles.
In order to rule out the initial SMH variations of enamel samples, SMH in all three groups was measured and found to have no statistically significant difference (P = 0.217). Hence, changes in microhardness values after intervention would be attributed to the fluoride therapy procedure.
The effect of fluoride ion on surface hardness of dental enamel has been investigated in numerous studies. Argenta et al. studied the effect of fluoride on the surface hardness of teeth and found that higher concentrations of fluoride ion were correlated with decrease in loss of inorganic content.
Wiegand also showed that increasing fluoride concentration results in higher microhardness of enamel samples.
Various forms of fluoridated products have been compared in former studies. Lee et al. in 2009 investigated the effectiveness of three local fluoride therapy agents (NaF 2% solution, APF foam, and fluoride varnish) and observed that changes in microhardness as a result of the application of these agents were not significantly different.
SDF is one of the latest fluoride-containing products that its influence on arresting caries has been evaluated formerly in several clinical studies. Chu et al. examined the effect of SDF and sodium fluoride varnish on arresting carious lesions in the dentin in Chinese children. After 30 months, they found SDF to be effective in arresting caries in deciduous anterior maxillary teeth. Yee et al. also found 38% silver fluoride to be effective in arresting dental caries.
There are controversial results comparing SDF and fluoride varnish efficacy. In a review of the article, it was reported that SDF is more effective than sodium fluoride in preventing caries. However, in contrary to these results, in a study on bovine incisors, Delbem et al. found that fluoride varnish displays a stronger effect on caries prevention.
Based on the results of our study, the difference of the effect of SDF and fluoride varnish on enamel resistance to demineralization was not statistically significant. This would be because the effect of SDF is more prominent on dentinal caries. In a study by Chu et al., it was shown that SDF is more effective on dentinal carious lesions. The reason is that dentinal tissue has a higher content of protein, carbonate, and phosphate available to react with silver. In contrast, these compounds are scarce in enamel tissue.
In the present study, samples treated with SDF and fluoride varnish showed higher quantitative resistance to demineralization compared to the control group. Even though this difference was not statistically significant, it can be substantial in clinical use. As we know, fluoride therapy is more effective in clinical practice if it is done repeatedly and regularly. By repeating fluoride therapy at least two times per year, the difference would be more significant clinically.
However, other researches also in former studies reported the same results. In 2009 Lee et al. examined the effect of three fluoride containing local agents on remineralizing incipient carious lesions. They found that fluoride did not have an increasing effect on SMH compared to the control group.
In dental practice, the most prominent disadvantage of silver compounds is the black discoloration, particularly on carious tissue and on occasion causes esthetic problems. Potassium iodide can be used to reduce this effect since silver iodide is white. Other studies have used other reducing agents to lower the amount of silver ions. Tannic acid has been used to facilitate the sedimentation of silver ions without interfering with anticaries effect of SDF.
In overall, discoloration in deciduous teeth or teeth that can be restored in future is not a prominent concern.
| Conclusion|| |
According to the present findings, SDF and fluoride varnish act similarly in preventing the demineralization of deciduous anterior teeth.
The authors would like to thank the Vice-Chancellory of Shiraz University of Medical Science for supporting this research. This manuscript is based on the thesis number: 1922 by Dr. Mohammad Hossein Farahmand Far with the advisory of Najmeh Mohammadi. The authors also thank Dr. Mehrdad Vosughi of the Center for Research Improvement of the School of Dentistry for the statistical analysis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]