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Prevention of Enamel Decalcification Using Fluoride Varnish
Int J Clin Prev Dent 2024;20(4):151-155
Published online December 31, 2024;  https://doi.org/10.15236/ijcpd.2024.20.4.151
© 2024 International Journal of Clinical Preventive Dentistry.

Hee Ja Na1, Moon Sil Choi2

1Department of Dental Hygiene, Honam University, 2Department of Dental Hygiene, Songwon University, Gwangju, Korea
Correspondence to: Moon Sil Choi
E-mail: ms9106@hanmail.net
https://orcid.org/0000-0003-3256-2481
Received October 25, 2024; Accepted December 10, 2024.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Objective: Recent years have seen an increase in enamel decalcification among orthodontic patients andadolescents due to increased consumption of carbonated beverages and poor oral hygiene practices. If leftuntreated, this enamel decalcification can progress to dental caries, potentially causing serious oral healthproblems. This study aims to evaluate the effectiveness of a fluoride varnish containing milk components,developed in Japan, in preventing enamel decalcification.
Methods: Twenty specimens, each measuring -1×1cm- were prepared from bovine anterior teeth that werecaries-free and had sound enamel surfaces. These specimens were randomly assigned to either a controlgroup or an experimental group, with 10 specimens in each group. The control group received notreatment, while the experimental group was treated with a Japanese fluoride varnish containing 900 ppm fluoride and milk components, applied according to the manufacturerʼs instructions. All specimens werestored in artificial saliva and evaluated at intervals of one, two, and three weeks.
Results: The control group showed results of 24.3±1.4 (p<0.044) at week 1, 37.3±2.6 (p<0.001) at week 2,and 41.5±1.8 (p>0.009) at week 3. The experimental group demonstrated results of 25.6±2.5 (p<0.044) atweek 1, 39.4±1.2 (p<0.001) at week 2, and 44.6±2.6 (p<0.009) at week 3. Both groups showed statisticallysignificant differences at weeks 1 and 2, with the experimental group exhibiting higher values.
Conclusion: This study confirmed that the application of fluoride varnish can effectively prevent enameldecalcification. In particular, fluoride varnish containing milk components remains on the tooth surface foran extended period, providing a sustained fluoride release effect that aids in enamel protection. Due to itsease of use and safety, this method is considered to have significant potential in preventing dental cariesamong orthodontic patients and adolescents.
Keywords : dental caries, enamel decalcification, fluoride varnish, milk protein, preventive dentistry
Introduction

Orthodontic treatment typically requires long-term care, often spanning several years. One of the most critical issues for patients with fixed orthodontic appliances is maintaining oral hygiene around the appliances. As the treatment period extends, patients may become less diligent in their self-care, leading to an increased likelihood of plaque and calculus accumulation around the brackets. This, in turn, elevates the risk of enamel decalcification or cavity formation [1].

Enamel decalcification or white spot lesions (WSLs) are very common side effects during orthodontic treatment and can occur in a significant number of orthodontic patients. These lesions primarily appear on the labial surfaces of the maxillary anterior teeth and may have limited improvement even after the removal of orthodontic appliances, potentially affecting the aesthetic outcome of the treatment [1].

Fluoride has excellent anti-caries effects in inhibiting enamel decalcification [2]. Fluoride varnish, in particular, has several advantages over other forms of fluoride preparations. It is well-accepted by patients and is known to have minimal side effects due to toxicity. Furthermore, it remains on the tooth surface for an extended period, providing a sustained release effect of fluoride [3].

The sustained release effect of fluoride varnish refers to the gradual release of fluoride over time after it adheres to the tooth surface. The most significant fluoride release occurs during the first three weeks after application, followed by a gradual release of fluoride thereafter [4]. Due to this characteristic, fluoride varnish can provide continuous protective effects over an extended period.

Fluoride varnish is easily accepted by patients due to its simple and convenient application method. Compared to traditional fluoride gels or foams, it has the advantages of shorter application time and can be easily and quickly applied even to young children [3].

However, there have been reports suggesting that the bond strength of brackets may decrease after fluoride application [4]. This could potentially be a significant issue in the early stages of orthodontic treatment, thus necessitating caution regarding the timing and method of fluoride varnish application.

Particularly in children and adolescents, initial carious lesions tend to progress rapidly. This is because the oral environment during this period creates favorable conditions for caries progression [5]. Therefore, for orthodontic patients, fluoride application to increase the acid resistance of dental tissues is generally recommended along with proper dental plaque management [6].

This study aims to investigate the enamel decalcification prevention effect using a fluoride varnish (containing 900 ppm fluoride) that includes components extracted from milk. This product contains a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) complex, which can promote remineralization of tooth structure [2]. Due to these characteristics, it is expected to effectively inhibit enamel decalcification and make a significant contribution to the prevention of dental caries in the future.

For the research method, we selected caries-free bovine anterior teeth with sound enamel surfaces from extracted teeth. These were divided into control and experimental groups for a comparative experiment over a 3-week period. Through this, we aim to objectively evaluate the enamel decalcification prevention effect of fluoride varnish containing milk components.

Materials and Methods

1. Participants and the study design

For this experiment, we selected caries-free bovine anterior teeth with sound enamel surfaces. Specimens were prepared in 1×1cm sizes, with a total of 20 specimens prepared. The control group received no treatment, while the experimental group had fluoride varnish (900 ppm fluoride, containing milk components, Japanese product) applied with a brush.

2. Enamel demineralization

1)Store the specimens at 37°C with 94% humidity for 24 hours.

2)Subsequently, immerse the specimens in a demineralizing solution for 96 hours to induce artificial deminerali-zation.

3)The demineralizing solution contains 50% saturated HAP at pH 5.0, 0.1 M lactic acid, and 0.2% Carbopol C907.

Lesion depth measurement was performed after 72 hours of the demineralization process. All specimens were sectioned to create slide samples, and under microscopic examination, the average of the four deepest points within a 5mm lesion area was used for measurement.

3. Processing statistics

Statistical analysis was performed using SPSS 21.0 program, and differences between each experimental group were compared through mean analysis. Significance testing was conducted at the p<0.05 level.

4. Ethical Considerations

This study was approved by the Institutional Review Board (IRB) of HONAM University (IRB No: 1041223-202303- HR-01).

Results

In Table 1, the control groupʼs product is V v vanish (Vericom, KOREA), with main contents of 5% NaF, Xylitol, Rosin, and TCP, and a Sample No. of 10.

Table 1 . Sample distribution

GroupProductMaunfactureMain contens Sample No
Control groupV v varnishVericom, KOREA5% naf, XYlitol, Rosin, TCP10
Experimental groupF g varnishGC, JAPEN900 ppm Fluorine-containing, milk calcium-containing10

In Table 1 , the control groupʼs product is V v vanish (Vericom, KOREA), with main contents of 5% NaF, Xylitol, Rosin, and TCP, and a Sample No. of 10.

The experimental groupʼs product is F g varnish (GC, JAPAN), with main contents of 900 ppm Fluorine-containing and milk calcium-containing, and a Sample No. of 10.



The experimental group's product is Tooth mooth (GC, JAPAN), with main contents of 900 ppm Fluorine-containing and milk calcium-containing, and a Sample No. of 10.

In Table 2, the control group showed results of 24.3±1.4 (p<0.044) at 1 week, 37.3±2.6 (p<0.001) at 2 weeks, and 41.5±1.8 (p>0.009) at 3 weeks. The experimental group demonstrated results of 25.6±2.5 (p<0.044) at 1 week, 39.4±1.2 (p<0.001) at 2 weeks, and 44.6±2.6 (p<0.009) at 3 weeks. Both the control and experimental groups showed significant results in the first and second weeks, but no significant results were observed in the third week. This suggests that applying fluoride varnish for at least 2 weeks may be sufficient to prevent tooth decalcification.

Table 2 . Remineralization period and group fine hardness

Group1 weekp2 weeksp3 weeksp
Control group24.3±1.40.04437.3±2.60.00141.5±1.80.009
Experimental group25.6±2.539.4±1.244.6±2.6

In Table 2 , the control group showed results of 24.3±1.4 (p<0.044) at 1 week, 37.3±2.6 (p<0.001) at 2 weeks, and 41.5±1.8 (p>0.009) at 3 weeks. The experimental group demonstrated results of 25.6±2.5 (p<0.044) at 1 week, 39.4±1.2 (p<0.001) at 2 weeks, and 44.6±2.6 (p<0.009) at 3 weeks. Both the control and experimental groups showed significant results in the first and second weeks, but no significant results were observed in the third week. This suggests that applying fluoride varnish for at least 2 weeks may be sufficient to prevent tooth decalcification.


Discussion

Local fluoride application has been widely used for dental caries prevention since its introduction as NaF topical application by Knutson and Amstong in 1943 [7]. While the exact mechanism of fluoride's caries prevention is not fully understood, it is generally known to work through the following actions. First, fluoride deposited on the tooth surface reduces the solubility of the enamel surface. Second, it inhibits demineralization caused by acids formed in dental plaque. Third, it promotes remineralization of initial enamel caries lesions. Fourth, it inhibits the growth of microorganisms that cause dental caries [8,9].

Fluoride varnish is a preparation that has been in development since the 1970s and is currently widely used [10]. In this study, the fluoride content of a single application of fluoride varnish (0.4 ml) for mixed dentition was 9.04 mg, which was found to be relatively safe compared to fluoride gel. The main characteristics and advantages of fluoride varnish are as follows. First, it has a longer contact time with tooth structure, allowing for more fluoride deposition. Second, it has an antibacterial effect against bacteria that cause initial dental caries. Third, it promotes remineralization of demineralized enamel. Fourth, it is effective in preventing decalcification during orthodontic treatment [11,12].

Fluoride varnish achieves high caries prevention effectiveness by combining fluoride with natural resins that have excellent adhesion to teeth, allowing for long-term contact of high-concentration fluoride. It also has the following clinical advantages. First, the procedure is simple and convenient, resulting in high patient compliance. Second, there is a low risk of excessive fluoride ingestion. Third, the application time is reduced compared to traditional fluoride gels or foams [13,14].

The results of this experiment showed a significant enamel decalcification prevention effect in the experimental group where fluoride varnish was applied. Notably, when fluoride varnish was applied for two weeks or more, the tooth decalcification prevention effect was markedly evident. This can be interpreted as a result reflecting the effective action mechanism of fluoride varnish.

Fluoride forms fluorapatite on the enamel surface, increasing resistance to acids, inhibiting demineralization, and promoting remineralization [15]. Additionally, the antibacterial action of fluoride is effective in preventing early dental caries by inhibiting the growth of caries-causing bacteria [16].

Clinical studies have confirmed that fluoride varnish prevents decalcification, which is an early symptom of dental caries, and delays the progression of existing enamel lesions [17-19]. This is believed to be due to the prolonged retention of fluoride varnish on the tooth surface, providing a continuous effect.

Fluoride varnish has the following practical advantages that make it easy to apply in clinical settings:

1. After application, it does not immediately disappear but remains on the tooth structure for an extended period, slowly releasing fluoride.

2. It can be applied quickly and easily, and it hardens rapidly, reducing chair time.

3. There is a low possibility of swallowing, making it highly safe.

4. It has almost no side effects compared to other forms of fluoride preparations [20,21].

Due to these characteristics, fluoride varnish is considered particularly suitable for application to pediatric and adolescent patients.

The results of this study confirm that fluoride varnish is an effective method for preventing enamel decalcification, and it has been shown to possess high safety and practicality. Particularly, when applied for more than two weeks, it shows a clear preventive effect and has the advantage of being easily used in clinical settings.

However, this study has several limitations. First, long-term effects were not evaluated. Second, further investigation is needed on the applicability in various clinical situations. In future research, it is considered necessary to address these limitations and conduct additional investigations on the long-term effects of fluoride varnish and its applicability in various clinical situations.

Conclusion

This study confirmed that fluoride varnish is an effective method for preventing enamel decalcification. Based on the research results, the following conclusions can be drawn:

Effectiveness of fluoride varnish: in this study, the experimental group treated with fluoride varnish showed a significant preventive effect on enamel decalcification compared to the control group. Notably, the effect became more pronounced when applied for two weeks or more.

Target population: fluoride varnish can be a particularly useful preventive method for high-risk groups such as patients undergoing orthodontic treatment or adolescents who frequently consume soft drinks. This is due to the higher risk of tooth decalcification and caries in these populations.

Safety and convenience: the application of fluoride varnish was found to be simple, safe, and highly acceptable to patients. This enhances its practicality in clinical settings.

Long-term effects: the application of fluoride varnish is expected to contribute to long-term oral health improvement. However, additional long-term studies are needed to confirm this.

Cost-effectiveness: fluoride varnish is considered a cost-effective preventive method due to its easy application and excellent efficacy. This suggests its potential for use in public oral health programs.

The limitations of this study include the short observation period and limited sample size. Therefore, the following directions are suggested for future research:

Studies are needed to develop optimal prevention protocols by comparing various concentrations of fluoride varnish with other preventive methods (e.g., fluoride gel, fluoride toothpaste).

Large-scale longitudinal studies should be conducted to evaluate long-term effects in real clinical settings. This will help to clarify the long-term efficacy and safety of fluoride varnish.

Economic analysis studies on the cost-effectiveness of fluoride varnish are necessary. This can provide important evidence for public health policy development.

Research targeting various age groups and risk populations should explore the possibility of expanding the application range of fluoride varnish.

In conclusion, this study demonstrates that fluoride varnish is an effective and safe method for preventing enamel decalcification. These findings can serve as supporting evidence for the use of fluoride varnish in clinical dental practice and public oral health programs. It is anticipated that future additional research will provide clearer guidelines on the long-term effects of fluoride varnish and its optimal application methods.

Conflict of Interest

No potential conflict of interest relevant to this article was reported.

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