Journal of Pharmacy And Bioallied Sciences

ORIGINAL ARTICLE
Year
: 2017  |  Volume : 9  |  Issue : 5  |  Page : 112--116

Effect of fluoride varnish and dentifrices and its combination on deciduous enamel demineralization: An In vitro study


Allama Prabhu1, BG Prasanna2, B Sakeenabhi1, GM Prashanth1, R Subramaniam3, Mallikarjuna Ragher4,  
1 Department of Public Health Dentistry, College of Dental Sciences, Davanagere, Karnataka, India
2 Department of Prosthodontics, College of Dental Sciences, Davanagere, Karnataka, India
3 Department of Public Health Dentistry, Indira Gandhi Institute of Dental Sciences, Kothamangalam, Kerala, India
4 Department of Prosthodontics, Yenepoya Dental College, Yenepoya University, Mangalore, Karnataka, India

Correspondence Address:
Allama Prabhu
Department of Public Health Dentistry, College of Dental Sciences, Davanagere - 577 002, Karnataka
India

Abstract

Introduction: Dental caries remains the most important dental health problem in developing countries. Application of varnish on tooth surfaces is shown to promote the uptake of firmly bound fluoride by enamel, which is considered important. Along with the incorporation of fluoride into the crystalline lattice, there is formation of calcium fluoride compounds on enamel. Methodology: Seventy deciduous canines were covered with nail polish. A window measuring 4 mm × 4 mm was left on their buccal surface, These were randomly assigned to seven groups (n = 6): S: sound enamel not subjected to any regimen or treatment; N: negative control, subjected to the pH-cycling regimen without any treatment; D1 and D2: subjected to the pH-cycling regimen and treated two times daily with 1100 and 500 ppm F dentifrice, respectively; VF: fluoride varnish (subjected to F-varnish before and in the middle of the pH-cycling regimen); and VF + D1 and VF + D2. After a period of 10 days, sectioning of teeth was done, and enamel demineralization was measured. Results: The combination of dentifrice and varnish (groups VF + D1 and VF + D2) significantly reduced demineralization compared with the N group at all distances evaluated (P < 0.05), but the combination did not differ from the dentifrice groups at most distances from the surface (P > 0.05). Conclusion: The results of this study suggest that the combination of F-varnish with dentifrices containing 500 or 1100 ppm F is not more effective in reducing demineralization in primary teeth than the isolated effect of dentifrice containing 1100 ppm.



How to cite this article:
Prabhu A, Prasanna B G, Sakeenabhi B, Prashanth G M, Subramaniam R, Ragher M. Effect of fluoride varnish and dentifrices and its combination on deciduous enamel demineralization: An In vitro study.J Pharm Bioall Sci 2017;9:112-116


How to cite this URL:
Prabhu A, Prasanna B G, Sakeenabhi B, Prashanth G M, Subramaniam R, Ragher M. Effect of fluoride varnish and dentifrices and its combination on deciduous enamel demineralization: An In vitro study. J Pharm Bioall Sci [serial online] 2017 [cited 2022 Aug 16 ];9:112-116
Available from: https://www.jpbsonline.org/text.asp?2017/9/5/112/219263


Full Text



 Introduction



Dental caries remains the most important dental health problem in developing countries. However, fluoride has been shown to improve remineralization of human enamel after acid attack and application of fluoride dentifrices have been effective in numerous clinical studies.[1] Common consensus from many reports worldwide, during the past decades, reveals that dental caries had declined significantly and was continuing to decline in populations. However, recent studies report alarming increases in caries, with increases mainly in children and adults, primary and permanent teeth, and include coronal and root surfaces. The emerging public health issues are related to disparities in the prevalence and treatment of dental caries.[2]

Methods used for prevention of dental caries vary widely among countries where caries reduction was observed. Studies conducted worldwide have shown several factors to explain this reduction. The factors include changes in diet, hygiene procedures, clinical management of caries, and the widespread use of fluoride. In addition, changes in the diagnostic criteria for a carious lesion also is an important factor. Caries also declined in communities in which no other important preventive method was available, except for fluoride dentifrices, whereas countries where fluoride toothpastes are not widely used the decrease in dental caries observed was less.[3]

Application of varnish on tooth surfaces promotes the uptake of firmly bound fluoride by enamel. Along with its incorporation into the crystalline lattice, fluoride varnishes and other concentrated topical fluorides interact with saliva and form calcium fluoride (CaF2) compounds on enamel. The formation of CaF2 has been considered to be an unwanted side reaction as it dissolves easily from the enamel soon after application. Studies from the 1980s reveal that CaF2 is stabilized by pellicle proteins and secondary phosphate at neutral pH. When the pH of plaque drops, CaF2 begins to dissolve and release fluoride ions, thus acting as a prolonged source of fluoride after application. Today, this is considered the most important factor in caries prevention for concentrated topical fluorides, including fluoride varnishes.[4]

The regular use of fluoridated dentifrice may be a beneficial preventive measure, independent of the occurrence of caries. However, Ögaard et al. suggested that, when the caries risk is high, this measure should be conducted with high concentration methods. The advantage of combining fluoridated dentifrice with professional applications has not been clearly understood, and further studies are necessary.[5]

The present study aimed to assess the preventive effect of 500 ppm F and 1100 ppm F fluoridated children's dentifrices and fluoride varnish in vitro, either applied in combination or alone, on primary teeth enamel after a caries challenge.

 Methodology



This in vitro study was done on seventy human extracted sound primary canine teeth. The samples were assessed visually and were free of caries or enamel defects.

Preparation of teeth specimens

All teeth were cleaned with a detergent solution and pumice powder using a low-speed motor. The teeth were then washed under running tap water for 1 min to eliminate debris. The root portion of all teeth was sealed with epoxy resin and then covered with red nail polish. A 4 mm × 4 mm window area on the buccal surface was left free of nail polish.

pH cycling

Teeth were subjected to the formation of artificial caries by pH cycling. The teeth were kept in demineralizing solution for 3 h and in remineralizing solution for 21 h. The demineralizing solution CaCl2 (2.2 mM), NaH2 PO4(2.2 mM), and acetic acid (0.05 M); pH of 4.5, adjusted with KOH (1M); 15 ml/tooth and remineralizing solution is CaCl2 (1.5 mM), NaHPO4 (0.9 mM), and KCl (0.15 mM); pH of 7.0; 15 mL/tooth. A total of 10 cycles were conducted. The teeth were briefly washed in deionized water during changing of solutions and placed in artificial saliva for 30 min (CaCl2 [15 mg], MgCl2 [5 mg], KCl [0.1 g], KSCN [10 mg], Na2 HPO4 [40 mg], sodium carboxymethyl cellulose [1.0 g], methyl paraben [0.1 g], and water [1 L]; pH of 7.0) [Figure 1].{Figure 1}

The de-remineralizing solutions were changed daily, and the artificial saliva was changed at every treatment.

Test groups

The teeth were divided into seven groups comprising ten teeth in each group. The groups were as follows:

Sound enamel group (S)Negative control group (N)Fluoride varnish group (VF)Fluoride varnish + 1100 ppm sodium fluoride dentifrice group (VF + D1)Fluoride varnish + 500 ppm sodium fluoride dentifrice group (VF + D2)1100 ppm sodium fluoride dentifrice group (D1)500 ppm sodium fluoride dentifrice group (D2).

Procedure

One of the groups comprising sound enamel (S) was not subjected to pH cycling and had no treatment. Group S was kept in deionized water and hardness assessment was done. The negative control (N) group had no treatment but was submitted to pH cycling. The remaining five groups (VF, VF + D1, VF + D2, D1, and D2) received topical fluoride treatment. Groups VF, VF + D1, and VF + D2 were treated with the fluoridated varnish Duraphat® (22,600 ppm F NaF and pH of 7.0) on the 5th and 10th days of the pH cycling. Duraphat® was applied to the delimited area (4 mm × 4 mm). The teeth were then stored in the remineralizing solution for 5 h. The varnish was removed with acetone, and the teeth were washed with deionized water for 1 minute and again immersed in the remineralizing solution. The varnish application was conducted within the 21 h that the teeth were kept in the remineralizing solution. During the pH cycling, the VF + D1 and VF + D2 groups were treated with the varnish as well as fluoridated dentifrice, while the D1 and D2 groups were only treated with fluoridated dentifrice. The VF + D1 and D1 groups were treated with the dentifrice (1100 ppm F in NaF, pH of 7.0) and the VF + D2 and D2 groups were treated with Colgate (500 ppm Fin NaF, pH of 6.9). The dentifrices were applied twice daily on the enamel at 10 a.m. and 4 p.m., bimanually brushing the surface for 1 min before changing the solutions. After every brushing period, the teeth were briefly washed in deionized water. To standardize the minimum amount of dentifrice used in the experiment, the lids of the Colgate and Colgate Baby were used. These lids close under pressure, and both have similar compartments for dentifrice dosage. According to Chedid and Cury, the dentifrice quantity accumulating in the lids is 0.16 g on an average. The standardized technique is to press the brush on the top of the lid once. The penetration of the brush into the lid is limited by the depth of the lid.

The teeth were then immersed in resin and cut along the crown's longitudinal axis through the middle of the window area to assess the hardness [Figure 2]. The cut surface was polished in a rotating machine using sand paper with grits of 320, 600, and 1200. The 320 grit papers were used for 30 s and the remaining two grit papers were used for 60 s each under running water. The polished surface was verified by visual inspection before using the next grit paper. For this procedure, the samples were held on top of the sand paper by hand, with minimum pressure. The final polish was conducted by felt discs and diamond paste at low speed. To remove debris, the samples were later washed and placed in a ultrasound bath for 12 min. The cross-sectional hardness measurements were made using a hardness tester with a Knoop indentor, static load of 25 g, and with 5 s of dwell time [Figure 3]. Three rows of five indentations each, separated by 100 μm, were made at 20, 40, 60, 80, and 100 μm from the outer dental surface of the exposed area. The mean hardness values (kg/mm²) of the three rows at each distance from the surface were then averaged and statistically analyzed within and between treatments.{Figure 2}{Figure 3}

Statistical analysis

Kolmogorov–Smirnov test was used for sample distribution, and a two-way ANOVA with repeated measures for distance and a post hoc Tukey test were used to verify differences in hardness between distances and treatments of the surface. The statistical analyses were conducted with the statistical software SPSS (IBM Corp, New York, USA) version 13.0, with a 5% significance level [Table 1].{Table 1}

 Results



Results showed statistical significance for the distance and group factors and the interaction between group and distance, which indicates that the effect of the treatments was different, depending on the depth of the enamel surface. The negative control (N) group showed that the produced lesion was narrow because the statistical difference was only observed at a distance of 20 μm from the enamel surface.

When the effect of the treatments was compared with the negative control group at each distance from the surface, the treatments with F-varnish (V) and 500 ppm F dentifrice (D2) were not effective (P > 0.05) in reducing enamel demineralization in all depths analyzed [Table 1]. At 20 μm of depth, the dentifrice with 1100 ppm F (group D1) significantly reduced demineralization compared with group N (P > 0.05), but did not differ in the other distances (P > 0.05). The groups VF + D1 and VF + D2 did not significantly differ at any distance from the surface (P > 0.05). The combination of dentifrice and varnish (groups VF + D1 and VF + D2) significantly reduced demineralization compared with the N group at all distances evaluated (P < 0.05), but the combination did not differ from the dentifrice groups at most distances from the surface (P > 0.05).

 Discussion



The pH cycling used in this study was as suggested by Chedid and Cury, which is specifically used for primary teeth. The daily 3-h demineralization cycle is related to effects that result when the patient ingests cariogenic products without removal of biofilm. It was observed in this study that there was a general enhanced preventative effect from combining fluoridated varnish with dentifrices (VF + D1 and VF + D2) compared with other groups.

The present study shows that remineralization of enamel using 1100 ppm fluoride is more effective than using 500 ppm fluoride. However, the study conducted by Rirattanapong et al.[6] showed that significant difference existed in the depth of enamel lesions among fluoridated dentifrice groups. This observation is in agreement with a study by Winter et al.[7] which concluded that experimental toothpaste with fluoride at 550 ppm had a similar anticaries effect as toothpaste containing fluoride at 1055 ppm. However, Damato et al.[8] concluded that there was a linear fluoride dose effect when individuals used dentifrices containing fluoride at 0, 250, and 1000 ppm. The differences in results may be due to the use of a different abrasive system and the type of fluoride used by Mellberg.[9]

Our results show that fluoridated varnish alone was not effective in reducing mineral loss. The results are same with the in vitro study conducted by Grodzka et al.[10] who found that the best preventative effect may be obtained when fluoridated varnish is used with other forms of fluoride supplements. Similarly, the present study demonstrated that lower mineral loss values were obtained in the VF + D2 and VF + D1 groups. However, other studies[11] have suggested that the combination of low fluoridated dentifrice and high fluoride concentration methods (fluoridated varnish) does not have additional benefits in remineralization and fluoride incorporation.

Fluoride incorporated into the enamel mineral during tooth development has little effect on the caries process. It is the fluoride that is incorporated posteruptive during the caries challenge that plays an important role in caries prevention.[12] The most effective caries-preventive fluoride regimen is provided by the daily application of topical fluoride in the form of dentifrices and mouth rinses.[13]

The critical pH range for demineralization and remineralization is between 4.3 and 5.0. Hypersaturation of calcium and phosphate ions causes re-precipitation of hydroxyapatite, forming an intact superficial layer on the enamel surface. Remineralization of enamel is enhanced by the presence of fluoride ions which leads to the formation of fluroapatite.[12]

Thus, fluoride plays an important role in the remineralization process. It acts as a catalyst and influences reaction rates with dissolution and transformation of various calcium phosphate minerals. The released mineral ions are re-precipitated as fluoroapatite which is less soluble and provides additional protection onto the apatite crystals.[12]

Independent of the distance from the surface, the VF group always showed the lowest values for hardness.[14] For the most superficial layers of the enamel, such as within 20 μm, where the teeth initially suffer cariogenic action, a decrease in hardness was observed for all treatments compared with the control group, similar to results found in study conducted by Gatti.[5]

At this distance, the effect of the 500 ppm F dentifrice (D2) was significantly different from the 1100 ppm F (D1) dentifrice, which showed greater hardness. The combination of fluoride varnish with dentifrices of different ppm (500 and 1100 ppm) also did not show an advantage compared with the 1100 ppm F dentifrice (D1) used alone.[5]

 Conclusion



The results of this study suggest that the combination of F-varnish with dentifrices containing 500 or 1100 ppm F is not more effective in reducing demineralization in primary teeth than the isolated effect of dentifrice containing 1100 ppm.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Shabanian M, Jabarifar SE, Salavati S, Khosravi K, Tavakoli N, Akhavan A, et al. Effect of fluoride dentifrices on the microhardness of deciduous enamel surfaces. Oral Health Prev Dent 2012;10:59-64.
2Bagramian RA, Garcia-Godoy F, Volpe AR. The global increase in dental caries. A pending public health crisis. Am J Dent 2009;22:3-8.
3Cury JA, Tenuta LM, Ribeiro CC, Paes Leme AF. The importance of fluoride dentifrices to the current dental caries prevalence in Brazil. Braz Dent J 2004;15:167-74.
4Seppä L. Fluoride varnishes in caries prevention. Med Princ Pract 2004;13:307-11.
5Gatti A, Camargo LB, Imparato JC, Mendes FM, Raggio DP. Combination effect of fluoride dentifrices and varnish on deciduous enamel demineralization. Braz Oral Res 2011;25:433-8.
6Rirattanapong P, Smutkeeree A, Surarit R, Saendsirinavin C, Kunanantsak V. Effects of fluoride dentifrice on remineralization of demineralized primary enamel. Southeast Asian J Trop Med Public Health 2010;41:243-9.
7Winter GB, Holt RD, Williams BF. Clinical trial of a low-fluoride toothpaste for young children. Int Dent J 1989;39:227-35.
8Damato FA, Strang R, Stephen KW. Effect of fluoride concentration on remineralization of carious enamel: An in vitro pH-cycling study. Caries Res 1990;24:174-80.
9Mellberg JR. Fluoride dentifrices: Current status and prospects. Int Dent J 1991;41:9-16.
10Grodzka K, Augustyniak L, Budny J, Czarnocka K, Janicha J, Mlosek K, et al. Caries increment in primary teeth after application of Duraphat fluoride varnish. Community Dent Oral Epidemiol 1982;10:55-9.
11Marinho VC, Higgins JP, Logan S, Sheiham A. Fluoride varnishes for preventing dental caries in children and adolescents (Review). Cochrane Libr 2002; 1:1-37.
12Sh P, Raghu R, Shetty A, Gautham P, Reddy S, Srinivasan R. Effect of organic versus inorganic fluoride on enamel microhardness: An in vitro study. J Conserv Dent 2013;16:203-7.
13White DJ, Nelson DG, Faller RV. Mode of action of fluoride: Application of new techniques and test methods to the examination of the mechanism of action of topical fluoride. Adv Dent Res 1994;8:166-74.
14Chedid S J, Cury J A. Effect of 0.02% NaF solution on enamel demineralization and fluoride uptake by deciduous teeth in vitro. Braz Oral Res2004;18:18-22.