|Year : 2020 | Volume
| Issue : 3 | Page : 247-252
Fluoride release and fluoride-recharging ability of three different sealants
Sneha S Patil1, Ujwal R Kontham2, Rakesh K Kontham3, Smita S Patil4, Sanjay P Kamble5
1 Department of Pediatric and Preventive Dentistry, Dr. D.Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, India
2 Pediatric Dentist - Private Practitioner, Mumbai, India
3 Department of Orthodontics, Nair Hospital Dental College, Mumbai, India
4 General Physician (MBBS), Pune, India
5 Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Pune, India
|Date of Submission||27-Nov-2019|
|Date of Decision||19-Jul-2020|
|Date of Acceptance||02-Sep-2020|
|Date of Web Publication||29-Sep-2020|
Dr. Sneha S Patil
Department of Pediatric and Preventive Dentistry, Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: We aimed to determine the fluoride release and fluoride-recharging ability of a sealant containing surface pre-reacted glass (S-PRG) ionomer filler particles (BeautiSealant) with a fluoride-releasing resin sealant (Helioseal F), and a glass-ionomer sealant (Fuji VII). Materials and Methodology: Forty-eight disc-shaped specimens of each material were immersed in deionized water to determine the fluoride release utilizing a fluoride ion-selective electrode. After 21 days, 8 specimens were soaked in 0.22% Sodium Fluoride solution for 2 min; 8 specimens were coated with 1.23% Acidulated Phosphate Fluoride (APF) gel for 4 min, and the fluoride-recharging ability was evaluated for 40 days. Data were analyzed using one way-ANOVA and Bonferroni post hoc tests. Results: Total fluoride release over the 21-day period was: Fuji VII > BeautiSealant > Helioseal F, (P = 0.000). After refluoridation of the specimens with 0.22% Sodium Fluoride solution, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal (P = 0.000). After exposure to 1.23% APF gel, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal F (P = 0.000). Conclusion: Glass ionomer-based sealants (Fuji VII) exhibited higher initial fluoride release whilst the surface pre-reacted glass-ionomer filler containing sealant (BeautiSealant) demonstrated superior fluoride recharging properties.
Keywords: Dental sealants, fluoride recharge, fluoride release, giomer, glass ionomer, resin-based material
|How to cite this article:|
Patil SS, Kontham UR, Kontham RK, Patil SS, Kamble SP. Fluoride release and fluoride-recharging ability of three different sealants. J Indian Soc Pedod Prev Dent 2020;38:247-52
|How to cite this URL:|
Patil SS, Kontham UR, Kontham RK, Patil SS, Kamble SP. Fluoride release and fluoride-recharging ability of three different sealants. J Indian Soc Pedod Prev Dent [serial online] 2020 [cited 2020 Oct 24];38:247-52. Available from: https://www.jisppd.com/text.asp?2020/38/3/247/296638
| Introduction|| |
The susceptibility of occlusal surfaces to caries has often been related to the varied morphology of pits and fissures on these surfaces. Since the introduction of pit and fissure sealants, their efficacy in caries prevention has been documented over the years. Resin-based fissure sealants are mainly used for sealing as they offer superior mechanical properties, wear resistance, and retention rates in comparison with glass-ionomer sealants., On the other hand, glass-ionomer sealants provide higher fluoride release and recharging abilities when compared to conventional resin-based sealants, but sealant loss is high due to inferior mechanical properties. To overcome these limitations, a resin-based fissure sealant containing surface pre-reacted glass (S-PRG) ionomer filler was introduced, the “giomers.” BeautiSealant contains a self-etching primer that eliminates the need for separate phosphoric acid etch and rinse steps. This reduces the working time and simplifies procedures, thereby lowering the chances for moisture/saliva contamination. Furthermore, it releases six ions – fluoride, sodium, strontium, aluminum, silicate, and borate which have shown to play a significant role in remineralization of the enamel surface.
It is well documented that the presence of fluoride ions in low, sustained concentrations for a sufficient period of time decreases the enamel demineralization and accelerates the remineralization process. However, the fluoride ions leached out from the fluoride-containing materials diminish over time; hence, the “recharging” of these materials with fluoride has been advocated to maintain a continuously increased level of fluoride release. In a clinical situation, both low and high fluoride concentrations play a significant role in caries prevention. No studies have been done in the past to compare the rechargeability and release of fluoride among different sealants that are profoundly used in clinical practice. The aim of this study, therefore, was to determine the fluoride release and recharging capabilities of BeautiSealant, Fuji VII, and Helioseal F with 0.22% Sodium Fluoride (NaF) solution (1000 ppm F-) and 1.23% Acidulated Phosphate Fluoride (APF) gel (12,300 ppm F-).
| Materials and Methodology|| |
The fissure sealants tested in this study are enlisted in [Table 1].
A metal ring mold (15 mm internal diameter, 1 mm height; ISO 6874:2015) was used to prepare 16 specimens of each material. Micro cover glasses (thickness 0.12–0.17 mm) were placed over the dispensed material. The specimens were cured on both the sides (for 20 s at one side) using LED (Elipar, 3M ESPE, 3M ESPE, St. Paul, USA) at 1200 mW/cm2, thereafter they were gently polished with Sof-Lex™ finishing and polishing discs.
Each prepared specimen was placed in 5 ml of deionized water in a plastic beaker and stored at 37°C ± 0.5°C during the experimental period. The first measurement of fluoride ion release was carried out 24 h after preparation of the specimens. 0.5 ml of total ionic strength adjustment buffer III was added to the storage media. The fluoride concentration was then measured using a fluoride ion-selective electrode (Orion 9609BNWP, Thermo Scientific Inc., USA) coupled to a benchtop analyzer (Orion Dual Star™ Series ISE Meter, Thermo Scientific Inc., USA); all data were recorded in ppm. The electrode was calibrated using four standard fluoride solutions of 1 ppm, 10 ppm, 50 ppm, and 100 ppm, before each measurement. Recalibrations were performed after every 10 measurements with the standard solutions of 1 and 10 ppm. After each measurement, the specimen was sufficiently rinsed with deionized water. All measurements were performed at a constant room temperature of 25°C ± 1°C for 21 days.
Re-fluoridation of the specimens was performed as follows. On day 21, after measurement of fluoride release, the specimens were cleansed by rinsing with deionized water for 5 min and dried on absorbent paper for 2 min. Out of the total, 8 specimens were then soaked in 0.22% NaF solution (1000 ppm F-) for 2 min, whereas the other 8 specimens were coated with 1.23% APF gel (12300 ppm F-, pH 3.2) for 4 min. The specimens were then rinsed with deionized water for 5 min, dried with absorbent paper on each side for 1 min, and placed in 5 ml of fresh deionized water at 37 °C. The measurements of the fluoride release were carried out daily for 40 days. This method of evaluation of fluoride release has been used in most previous studies.,,,,,,,,,
| Results|| |
Data were recorded and analyzed with SPSS ver. 16.0 (SPSS Inc., Chicago, IL, USA). A one-way ANOVA test was used to compare the significance of difference in fluoride release and fluoride recharging between the three groups at a level of significance of P ≤ 0.05. The differences in fluoride concentrations among the experimental groups were detected using a Bonferroni post hoc test, with P ≤ 0.05 considered statistically significant.
Fluoride release ability
On Day 1, BeautiSealant exhibited higher fluoride release ability (16.11 ppm) compared to Fuji VII (11.6 ppm) and Helioseal F (4.81 ppm), which was statistically significant (P = 0.000). The fluoride release from the sealants reduced over time. The total fluoride release over the 21-day experimental period for Fuji VII (9.39 ± 4.75 ppm) was higher when compared to the giomer, BeautiSealant (4.63 ± 3.41 ppm), and the resin-based fluoride-containing sealant, Helioseal F (1.21 ± 1.50 ppm). Statistical analysis revealed significant differences in fluoride release among the tested materials (P = 0.000) [Table 2] and [Figure 1]a.
|Table 2: Comparison of fluoride release during the 21-day experimental period|
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|Figure 1: (a) Fluoride release from the tested materials during the 21-day experimental period. (b) Fluoride release from the tested materials after refluoridation with 0.22% Sodium Fluoride solution. (c) Fluoride release from the tested materials after refluoridation with 1.23% Acidulated Phosphate Fluoride|
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Fluoride recharge ability
After refluoridation with 0.22% NaF solution and 1.23% APF gel, all the three materials demonstrated different fluoride release. BeautiSealant presented higher fluoride recharge property over Fuji VII and Helioseal F, after treating the specimens with 0.22% NaF solution. The cumulative fluoride release over the 40-day period was calculated as: BeautiSealant (0.58 ± 1.89 ppm) > Fuji VII (0.51 ± 2.27 ppm) > Helioseal F (0.05 ± 0.44 ppm). This difference was statistically significant (P = 0.000) [Table 3] and [Figure 1]b.
|Table 3: Comparison of fluoride during the 40-day period after refluoridation with 0.22% sodium fluoride solution|
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After exposure to 1.23% APF gel, BeautiSealant exhibited greater fluoride release as compared to Fuji VII and Helioseal F; the cumulative fluoride release seen was: BeautiSealant (5.69 ± 16.13 ppm) > Fuji VII (3.35 ± 2.54 ppm) > Helioseal F (0.50 ± 3.0 ppm). This difference was statistically significant (P = 0.000) [Table 4] and [Figure 1]c.
|Table 4: Comparison of fluoride release during the 40-day period after refluoridation with 1.23% acidulated phosphate fluoride gel|
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| Discussion|| |
The combination of sealant and fluoride application – both home regimen and topical, has shown synergistic anticariogenic properties which could partially stem from the release and rechargeability of fluoride-releasing fissure sealants. This study investigated the fluoride release over a period of 21 days and fluoride release after recharging with both low and high fluoride concentrations over a period of the next 40 days. The results obtained are in concordance with the literature.,,,,, Glass-ionomer-based materials generally release higher fluoride. In the present study, Fuji VII exhibited a significantly higher cumulative fluoride-releasing pattern compared to the resin-based sealants, similar to that of Kusşgöz et al. and Bayrak et al. Various factors ensue the release of fluoride ions from sealants including their composition, solubility and porosity, pH,,, type of storage media used,,, the degree of polymerization, and the exposed surface area for application.
The greatest fluoride release was detected during the first few days, after which the release rate dropped, but remained relatively constant until the end of 21 days. This pattern of fluoride release has been described in various previous studies.[5-8,13] The fluoride release on Day 1 is thought to be induced by superficial rinsing effect, and later, the same is attributed to its ability to diffuse through cement pores and fractures.
Interestingly, BeautiSealant showed a constant release of fluoride till Day 17, whence a plateau-like effect was observed which did not attain zero level exhibiting some amount of fluoride release, a trait that could be attributed to its composition.
Professional topical fluoride applications usually contain 1.23% APF gel (12,300 ppm F-), whereas dentifrices used routinely at home contain 1000 ppm F- (0.22% NaF) for 2 min, a regimen feasibly employed in child patients; the same was employed in the study.
Statistical analysis revealed the existence of significant differences among the tested materials with regard to release of fluoride ions after treatment with 0.22% NaF solution and 1.23% APF gel. This is in accordance with previous investigations.,,, In both fluoride regimens, after fluoride recharge, on Day 1, the giomer, BeautiSealant, presented higher fluoride release when compared to Helioseal F and Fuji VII.
The results of the current research are in agreement with the findings of otherin vitro studies which have suggested that after recharging of fluoride-containing restorative materials, the amount of fluoride ions increased in the first 24 h, followed by a rapid return to near pre-exposure levels within a few days., After exposure to 1.23% APF gel, BeautiSealant showed a dramatic increase in fluoride release (24.10 ppm) on Day 22 (i.e., Day 1 after fluoridation), even exceeding the levels of fluoride release on Day 1 (16.11 ppm), testifying to the fact that restorative materials can function as a fluoride reservoir [Table 4]. This was contrary to the findings of Dionysopoulos et al. and Alvarez et al. who have stated that this fluoride release is lower than the initial fluoride release of the materials but is still significant.
The results about BeautiSealant's recharging capability with low concentration of fluoride are corroborated by the results of other studies. Shimazu et al., who evaluated the fluoride recharge ability of three resin-based fissure sealants, reported increased fluoride release after treatment with NaF solution from BeautiSealant, followed by Teethmate F-1 and Delton FS.
A significant fact noted in this study was that for the resin-based fluoride-containing sealant after Day 6-after refluoridation, the fluoride release was at the same level (i.e., zero) as before the refluoridation procedure (Day 21). This demonstrated that Helioseal F did not release significant amounts of fluoride despite daily fluoridation with low concentration of fluoride agent. This may be accredited to its composition.
For all the three groups, the total amount of fluoride released was significantly higher for 1.23% APF gel than exposure to 0.22% NaF solution. The difference in the behavior of these sealants could prove to be of significance after recharging with 1.23% APF gel – though BeautiSealant exhibited a steep decline by Day 5 when compared to a gradual decrease shown by Helioseal F and Fuji VII on the same day, the amount of fluoride released by BeautiSealant was fourfold.
The results of the present study are in agreement with Xu and Burgess that materials with higher initial fluoride release have higher recharge capacity.
The amount of fluoride released after exposure to fluoride gel is dependent on the soluble fluoride concentration., The use of dental materials with the highest and prolonged fluoride release is advantageous because when the fluoride ion is present in the saliva and biofilm, the enamel solubility is low., The minimum amount of fluoride that must be released to initiate remineralization in enamel and inhibit demineralization has not been precisely known.,, Eichmiller and Marjenhoff reported that this value is between 0.02 and 0.06 ppm, whereas Jacobson et al. showed that a concentration of 3 ppm has a significant effect in preventing caries. Due to the fact that fluoride release decreases over time, the recharging of fluoride-releasing materials may maintain a continuously increased level of fluoride ions around the teeth, especially significant in children who are considered to be at high risk for dental caries.
As with anyin vitro investigation, the present study too is not without drawbacks. A limitation of this study is the lack of anin vivo environment – the oral cavity with temperature changes, masticatory forces, and chemical attacks by acids and enzymes provide a challenge to survival of restorations. Moreover, in the mouth, it is probable that some of the fluoride release is available for ionic substitution of the mineral phase of the enamel. Further studies are needed to confirm the fluoride-recharging mechanism as it is not certain if it plays an important role in caries inhibition in vivo.
| Conclusion|| |
To optimize the possibility of recurrent caries inhibition, especially in high-caries-risk patients, a sustained release of fluoride levels over time from a sealant is necessary. Recharging of sealants with high concentration of fluoride such as 1.23% APF gel will enhance the fluoride release and prove critical in maintaining the balance between remineralization and demineralization. S-PRG ionomer filler-containing sealant, BeautiSealant, demonstrated higher fluoride release after recharging with both low (1000 ppm F-) and high (12,300 ppm F-) concentrations over conventional resin-based fluoride-releasing sealant and a glass-ionomer sealant. Furthermore, as this product does not require etching, it reduces the chairside time proving beneficial, especially in pediatric dentistry. Well-planned long-term clinical studies are imperative to arrive at further concrete conclusions.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]