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Long-term release of fluoride from fissure sealants—In vitro study
Journal of Trace Elements in Medicine and Biology 41 (2017) 107–110
Contents lists available at ScienceDirect
Journal of Trace Elements in Medicine and Biology journal homepage: www.elsevier.com/locate/jtemb
Toxicology
Long-term release of fluoride from fissure sealants—In vitro study a,∗ b,c ´ ´ Piotr Kosior a , Maciej Dobrzynski , Mariusz Korczynski , Katarzyna Herman a , a ´ ˛ a, Agnieszka Czajczynska-Waszkiewicz , Małgorzata Kowalczyk-Zajac a a d ´ Dagmara Piesiak-Panczyszyn , Katarzyna Fita , Maciej Janeczek a
Department of Conservative Dentistry and Pedodontics, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland Department of Environment Hygiene and Animal Welfare, Wroclaw University of Environmental and Life Sciences, Chełmo´ nskiego 38c, 51-630 Wroclaw, Poland c Department of Experimental Surgery and Biomaterials Research, Wroclaw Medical University, Poniatowskiego 2, 50-326 Wroclaw, Poland d ˙ Department of Biostructure and Animal Physiology, Wroclaw University of Environmental and Life Sciences, Kozuchowska 1, 51-631 Wroclaw, Poland b
a r t i c l e
i n f o
Article history: Received 26 November 2016 Received in revised form 4 February 2017 Accepted 27 February 2017 Keywords: Fissure sealant Fluoride ions Release
a b s t r a c t The intensity of the cariostatic activity of fluoride ions can be attributed to their multidirectional influence on the caries process. They are an irreplaceable factor that helps sustain mineral balance of dental tissues, simultaneously demonstrating antibacterial properties. As a consequence, many manufacturers of fissure sealants include fluoride ions in their products. The aim of this in vitro study was to determine long-term fluoride release from four fissure sealants (Conseal F, Fissurit FX, Delton Fs+, Admira Seal). During a 14week-long observation, all the materials showed a relatively constant level of F- release; however, it is crucial to mention that within the first 48 h, the most significant increase in fluoride release was found for Fissurit and Delton sealants. Based on the overall assessment, the highest total amount of the released fluoride ions was observed for Delton, and the lowest level was reported for Admira Seal. © 2017 Elsevier GmbH. All rights reserved.
1. Introduction The intensity of the cariostatic action of fluoride ions can be attributed to their multidirectional influence on the caries process [1–5]. Starting from their endogenous activity impacting hard dental tissues in the mineralization period, to external protection in the oral cavity environment, they are an irreplaceable factor that helps sustain mineral balance of the teeth. As a result of concentrating in the dental plaque and constant dissociation from the saliva, they show considerable potential for inhibiting the demineralization processes by supporting the remineralization processes. They stimulate restoration of apatites, and they reduce loss of calcium ions from the enamel surface which is connected with the activity of acids present in oral cavity environment. The mechanisms of the preventive action of fluoride are various [1,4–6]. Fluorides react with hydroxyapatites of the enamel by replacing hydroxide ions. As a result of this reaction, some of the hydroxyapatites transform into fluorapatites which have better crystalline properties, and are more acid-resistant. In the apatite, strong ionic bonds between fluoride and the NH group
∗ Corresponding author. E-mail address: [email protected] (M. Janeczek). http://dx.doi.org/10.1016/j.jtemb.2017.02.014 0946-672X/© 2017 Elsevier GmbH. All rights reserved.
of the organic enamel matrix are formed, which contributes to greater stability of fluorapatite crystals. Fluoride may also react with apatite by stimulating the growth of fluorapatite crystals, as well as it may cause apatite dissolution and forming calcium fluoride. The formation and stimulation of fluorapatite growth may occur during frequent exposure to low fluoride concentration in the solutions (below 0.1%). Many researchers have confirmed the significant role of fissure sealants in the prevention of dental caries in molars and premolars [7–15]. Slow release of the fluoride that they contain has a considerable influence on the intensification of the cariostatic action. 2. Aim The aim of this in vitro study was to determine long-term fluoride release from selected fissure sealants. 3. Material and methods The study involved four fissure sealants (Conseal F, Fissurit FX, Delton Fs+, Admira Seal) which contained the following: • Conseal F (SDI, Australia) – by weight 93% acrylic monomer, 7.0% silica, 0.01% titanium dioxide and 0.01% NaF.
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P. Kosior et al. / Journal of Trace Elements in Medicine and Biology 41 (2017) 107–110
Table 1 Cumulated in vitro F− ion release from fissure sealants into a saline solution (g/mm2 ). Time (hours)
Conseal F (±SD) (g/mm2 )
Fissurit FX (±SD) (g/mm2 )
Delton FS+ (±SD) (g/mm2 )
Admira Seal (±SD) (g/mm2 )
1 3 24 48 72 168 336 504 672 840 1008 1176 1344 1512 1680 1848 2016 2184 2352 Correlation coefficient
1.25 (±0.04) 2.98 (±0.9) 5.31 (±1.46) 6.58 (±1.94) 7.74 (±2.14) 9.39 (±2.17) 11.13 (±2.2) 12.97 (±2.27) 14.97 (±2.62) 17 (±2.92) 17.48 (±2.97) 17.92 (±2.93) 18.22 (±2.92) 18.77 (±2.85) 19.01 (±2.73) 19.13 (±2.75) 19.15 (±2.75) 19.23 (±2.79) 19.83 (±2.8) 0.8925
4.04 (±0.21) 5.78 (±0.5) 8.08 (±1.28) 9.18 (±1.56) 9.75 (±1.7) 11.04 (±2.1) 12.19 (±2.35) 12.92 (±2.33) 14.42 (±2.07) 15.64 (±2.01) 16.84 (±2.47) 18 (±2.73) 19.17 (±2.98) 20.43 (±3.15) 21.59 (±3.14) 22.83 (±3.14) 24.13 (±3.15) 25.58 (±3.09) 28.08 (±3.1) 0.982
3.8 (±0.69) 5.21 (±0.96) 11.4 (±3.16) 14.93 (±3.96) 18.11 (±4.87) 23.93 (±4.84) 29.44 (±6.16) 31.55 (±6.83) 34.2 (±7.7) 36.16 (±7.96) 37.83 (±7.97) 39.62 (±7.98) 41.86 (±8.41) 44.78 (±7.96) 46.48 (±8.1) 48.33 (±8.51) 51.93 (±9.49) 55.81 (±10.67) 61.91 (±12.07) 0.9531
0.19 (±0.02) 0.52 (±0.32) 0.65 (±0.3) 0.76 (±0.31) 0.88 (±0.25) 0.99 (±0.23) 1.27 (±0.21) 1.36 (±0.21) 2.55 (±0.27) 2.92 (±0.25) 3.28 (±0.24) 3.74 (±0.23) 4.25 (±0.25) 4.66 (±0.25) 5.28 (±0.3) 5.87 (±0.34) 6.34 (±0.37) 6.83 (±0.42) 7.36 (±0.3) 0.9971
T-test for two variables Admira Seal Delton FS+ Fissurit FX Conseal
0.0000 0.0000 0.0009 xxx
0.0000 0.0000 xxx
0.0000 xxx
xxx
Friedman’s ANOVA and Kendall’s Coefficient of Concordance. Chi 2 ANOVA (N = 19, df 3) = 50.55789 p 0.00000. Coefficient of Concordance = 0.88698 r average range = 0.88070.
• Fissurit FX (Voco, Germany) – composed of a monomer matrix which consists of methacrylic acid ester (BIS-GMA) and urethane dimethacrylate (around 99%) and a filler – borosilicate glass with the particle size above 1 m (99%), and 3% NaF which corresponds to1.3% fluoride content. • Delton FS+ – it contains two sources of fluoride, by volume 55% of the filler. • Admira Seal – mainly composed of borosilicate glass (16%). The release of fluoride ions from the aforementioned materials to a saline solution was examined for 14 weeks (i.e. 98 days or 2352 h). Samples of the studied materials were formed as cylinders with the use of a polyethylene matrix. The polymerization of a material was conducted according to the recommendations of the manufacturer. After the samples have been hardened, they were polished and their contact surface was calculated in mm2 . Samples were then immersed in the examined solution and left undisturbed in closed containers at the temperature of 37 ◦ C (oral cavity conditions) for a period of time necessary for measurements of the level of fluoride release from the materials. Three samples were made for each material. The ion selective ORION electrode model 9609, and a microcomputer pH/ionometer CPI- 551 Elmetron were used for measurements. The system was calibrated before every examination. Each sample was examined three times, and an average value was calculated based on the three results. The results were collected after 1 and 3 h, next after 1, 2, and 3 days, and then at weekly intervals for 14 consecutive weeks. For individual measurements series, the average as well as the standard deviation of average were calculated. Obtained results of cumulated content of fluorine ions in saline solution were statistically analyzed using Friedman test for repeated data as well as T-student test for dependent data. Coefficient of Pearson’s line correlation between cumulated concentration of fluoride ions and exposure time of the material in saline solution were also calculated. Results of fluoride ions concentration at each time-point were analyzed statistically using of T-student test for dependent data.
All the calculations were performed for the level of significance p < 0,05.
4. Results The levels of fluoride release from the samples of fissure sealants into a saline solution are shown in Table 1 and on Fig. 1. The highest cumulated level of ion release was demonstrated by Delton FS+ (61.91 ± 12.07 g F/mm2 ), and a lower on by Fissurit FX (28.08 ± 3.10 g F/mm2 ), Conseal F (19.83 ± 2.80 g F/mm2 ) and Admira Seal (7.36 ± 0.30 g F/mm2 ) respectively. Extended time of the materials remaining in the saline solution equaled a higher level of released fluorides. All the examined materials showed the highest rate of emission after 1 h; the highest rate was demonstrated by Fissurit FX (4.0400 g F/mm2 /h.), lower by Delton FS+ (3.800 g F/mm2 /h.) and Admira Seal (0.1900 F/mm2 /h.), and the lowest by Conseal (1.2500 g F/mm2 /h.). The rate of fluoride release for all the materials within the following 2 h decreased; the smallest decrease was observed for Admira Seal (of 13%), and the largest for Delton FS+ (of 81%) (Table 2).
5. Discussion The antibacterial activity of fluoride is visible in local concentrations ranging from 0.16 to 0.31 mol/l. In normal conditions, lower amounts of fluoride are observed in the dental plaque [16]. However, it has been demonstrated that low concentrations (around 1 mmol/l) may effectively inhibit the production of bacterial acids, and at the same time, reduce the demineralization of the tooth surface [4,17]. Most of the research conducted so far on fluoride release from dental materials is inconclusive with regards to the solution the measurements should be taken in. The diversity of environments used for taking the measurements is to show their influence on the release level and the significance of the differences [1].
P. Kosior et al. / Journal of Trace Elements in Medicine and Biology 41 (2017) 107–110
109
Fig. 1. Cumulated in vitro F− ion release from fissure sealants into a saline solution (g/mm2 ).
Table 2 Hourly in vitro increments of F− ions release from fissure sealants into a saline solution (g/mm2 ). Increments/h Time (hour)
Conseal (g/mm2 )
Fissurit FX (g/mm2 )
Delton FS+ (g/mm2 )
Admira Seal (g/mm2 )
1 3 24 48 72 168 336 504 672 840 1008 1176 1344 1512 1680 1848 2016 2184 2352 Average Standard Deviation
1.2500 0.8650 0.1109 0.0529 0.0483 0.0171 0.0103 0.0109 0.0110 0.0120 0.0028 0.0026 0.0017 0.0032 0.0014 0.0007 0.0001 0.0008 0.0035 0.1266 0.3353
4.0400 0.8700 0.1095 0.0458 0.0237 0.0134 0.0068 0.0043 0.0089 0.0072 0.0071 0.0069 0.0069 0.0075 0.0069 0.0073 0.0077 0.0086 0.0148 0.2738 0.9330
3.8000 0.7050 0.2947 0.1470 0.1325 0.0606 0.0328 0.0125 0.0157 0.0116 0.0099 0.0106 0.0133 0.0173 0.0101 0.0110 0.0214 0.0231 0.0363 0.2824 0.8678
0.1900 0.1650 0.0061 0.0045 0.0050 0.0011 0.0016 0.0005 0.0070 0.0022 0.0024 0.0027 0.0030 0.0024 0.0036 0.0035 0.0028 0.0029 0.0031 0.0215 0.0551
T-test for two variables Admira Seal Delton FS+ Fissurit FX Conseal F
0.1202 0.2595 0.3292 xxx
0.2302 0.6824 xxx
0.1834 xxx
xxx
The manufacturers of electrodes (e.g. the Orion electrode) used for recording such measurements usually recommend the use of deionized water; however, it is the saline solution that seems to be the most neutral environment that reflects the isotonicity of our organism [1,2]. Deionized water does not always prove to be the best model solution. Thanks to the ionic strength, which is crucial in the process of fluoride ions release and their measurements, saline appears to be a more appropriate option [1–3]. The basic aim of applying fissure sealants is long-term protection of pits and fissures against the development of dental caries [1–6,12,18,19].
The fissure sealants include materials based on glass ionomer cement as well as materials based on Bis-GMA resin. Glass ionomer cement materials demonstrate low retention and low resistance to abrasion and wear, and their anti-cariogenic properties can be attributed to long-term release of fluoride [4,15,18–21]. Bis-GMA resin based materials release less fluoride, and they demonstrate much higher adhesion to the enamel, which guarantees their long clinical retention [4,7,19]. Currently, they are the most commonly used for caries prevention.
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On the market, there are many fissure sealant products available; practically every manufacturer offers such a material. Due to the frequency of clinical application, composite based materials were examined, including Conseal (SDI), Fissurit FX (Voco), Delton FS+ (Johnson&Johnson), and Admira Seal (Voco) based on the ormocer technology. Long-term observation of the fluoride release from the examined materials shows similar properties in this respect. Nevertheless, it is crucial to emphasize that there are differences in terms of the total amount of the released fluoride. 6. Conclusions According to modern guidelines of scientific societies on caries prevention, long release of fluoride in low concentrations is superior to high-dose released in a short time [22]. In our research during the 14-week-long observation, all the materials showed a relatively constant F− release level. It is important to point out that the highest release increase within the first 48 h was observed for the Fissurit FX and Delton FX+ sealants. Based on the overall assessment, the highest total amount of the released fluoride ions was observed for Delton FX+ which may reveal the highest cariostatic effectiveness comparing to other examined fissure sealants. Conflict of interests The authors declare that there is no conflict of interests regarding the publication of this paper. References [1] P. Kosior, Fluoride Release from Selected Dental Materials in Experimental and Clinical Conditions, Wroclaw Medical University, 2005 (Doctorial Thesis). [2] P. Kosior, U. Kaczmarek, Release of fluoride ions into saliva from some dental materials, Ann. Acad. Med. Stetin. 50 (2004) 62–64. [3] P. Kosior, U. Kaczmarek, Effect in vitro of environmental parameters on the release of fluoride ions from some materials used in dentistry, Ann. Acad. Med. Stetin. 50 (2004) 65–68. [4] N. Beiruti, M.A. Frencken, M.A. van’t Hof, W.H. van Palenstein Helderman, Caries preventive effect of resin-based and glass ionomer sealants over time: a systemic review, Community Dent. Oral Epidemiol. 34 (2006) 403–409. [5] A. Ahovou-Saloranta, H. Forss, T. Walsh, A. Hiiri, A. Nordblad, M. Makela, et al., Sealants for preventing dental decay in the permanent teeth, Cochrane Database Syst. Rev. 28 (2013) CD0018303.
[6] A. Aksoy, E. Ertas, D. Guveno, S. Ozer, Fluoride release and recharge from different materials used as a fissure sealants, Eur. J. Dent. 4 (2010) 245–250. ´ [7] J.M. Kobierska-Brzoza, M. Dobrzynski, K.A. Fita, D. Bader-Orłowska, M. Szymonowicz, Currently recommended restorative materials in modern conservative dentistry, Polim. Med. 45 (2015) 37–43. [8] E.N. Salmerón-Valdés, R.J. Scougall-Vilchis, J. Alanis-Tavira, R.A. Morales-Luckie, Comparative study of fluoride released and recharged from conventional pit and fissure sealants versus surface prereacted glass ionomer technology, J. Conserv. Dent. 19 (2016) 41–45. [9] M.G. Cagetti, G. Carta, F. Cocco, S. Sale, G. Congiu, A. Mura, L. Strohmenger, P. Lingström, G. Campus, Effect of fluoridated sealants on adjacent tooth surfaces: a 30-mo randomized clinical trial, J. Dent. Res. 93 (2014) 59S–65S. [10] M. Kaga, S. Kakuda, Y. Ida, H. Toshima, M. Hashimoto, K. Endo, H. Sano, Inhibition of enamel demineralization by buffering effect of S-PRG filler-containing dental sealant, Eur. J. Oral Sci. 122 (2014) 78–83. [11] Y. Fan, J. Townsend, Y. Wang, E.C. Lee, K. Evans, E. Hender, J.L. Hagan, X. Xu, Formulation and characterization of antibacterial fluoride-releasing sealants, Pediatr. Dent. 35 (2013) 13–18. [12] K. Shimazu, K. Ogata, H. Karibe, Evaluation of the ion-releasing and recharging abilities of a resin-based fissure sealant containing S-PRG filler, Dent. Mater. J. 30 (2011) 923–927. [13] S. Bayrak, E.S. Tunc, A. Aksoy, E. Ertas, D. Guvenc, S. Ozer, Fluoride release and recharge from different materials used as fissure sealants, Eur. J. Dent. 4 (2010) 245–250. [14] Cildir S. Kavaloglu, N. Sandalli, Compressive strength surface roughness, fluoride release and recharge of four new fluoride-releasing fissure sealants, Dent. Mater. J. 26 (2007) 335–341. [15] X. Chen, V. Cuijpers, M. Fan, J.E. Frencken, Marginal leakage of two newer glass-ionomer-based sealant materials assessed using micro-CT, J. Dent. 38 (2010) 731–735. [16] M. Maltz, C.G. Emilsson, Susceptibility of oral bacteria to various fluoride salts, J. Dent. Res. 61 (1982) 786–790. [17] J.P. Loyola-Rodriquez, F. Garcia-Godoy, R. Lindquist, Growth inhibition of glass ionomer cements on mutans streptococci, Pediatr. Dent. 16 (1994) 346–349. [18] N. Beiruti, J.E. Frencken, M.A. van’t Hof, D. Taifour, W.H. van Palenstein Helderman, Caries-preventive effect of a one-time application of composite resin and glass ionomer sealants after 5 years, Caries Res. 40 (2006) 52–59. [19] V. Yengopal, S. Mickenautsch, A.C. Bezerra, S.C. Leal, Caries preventive effect of glass ionomer and resin-based fissure sealants on permanent teeth: a meta-analysis, J. Oral Sci. 51 (2009) 373–382. [20] C.J. Kleverlaan, R.N. van Duinen, A.J. Feilzer, Mechanical properties of glass ionomer cements affected by curing methods, Dent. Mater. 20 (2004) 45–50. [21] W.W. Zhang, X. Chen, M.W.J. Fan. Mulder, M.Ch. Huysmans, J.E. Frencken, Do light cured ART conventional high-viscosity glass-ionomer sealants perform better than resin-composite sealants: a 4-year randomized clinical trial, Dent. Mater. 30 (2014) 487–492. [22] D. Olczak-Kowalczyk, M. Borysewicz-Lewicka, B. Adamowicz-Klepalska, T. Jackowska, U. Kaczmarek, Consensus statement of Polish experts on individual caries prevention with fluoride in children and adolescents, Nowa Stomatol. 21 (2016) 47–73.
Contents lists available at ScienceDirect
Journal of Trace Elements in Medicine and Biology journal homepage: www.elsevier.com/locate/jtemb
Toxicology
Long-term release of fluoride from fissure sealants—In vitro study a,∗ b,c ´ ´ Piotr Kosior a , Maciej Dobrzynski , Mariusz Korczynski , Katarzyna Herman a , a ´ ˛ a, Agnieszka Czajczynska-Waszkiewicz , Małgorzata Kowalczyk-Zajac a a d ´ Dagmara Piesiak-Panczyszyn , Katarzyna Fita , Maciej Janeczek a
Department of Conservative Dentistry and Pedodontics, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland Department of Environment Hygiene and Animal Welfare, Wroclaw University of Environmental and Life Sciences, Chełmo´ nskiego 38c, 51-630 Wroclaw, Poland c Department of Experimental Surgery and Biomaterials Research, Wroclaw Medical University, Poniatowskiego 2, 50-326 Wroclaw, Poland d ˙ Department of Biostructure and Animal Physiology, Wroclaw University of Environmental and Life Sciences, Kozuchowska 1, 51-631 Wroclaw, Poland b
a r t i c l e
i n f o
Article history: Received 26 November 2016 Received in revised form 4 February 2017 Accepted 27 February 2017 Keywords: Fissure sealant Fluoride ions Release
a b s t r a c t The intensity of the cariostatic activity of fluoride ions can be attributed to their multidirectional influence on the caries process. They are an irreplaceable factor that helps sustain mineral balance of dental tissues, simultaneously demonstrating antibacterial properties. As a consequence, many manufacturers of fissure sealants include fluoride ions in their products. The aim of this in vitro study was to determine long-term fluoride release from four fissure sealants (Conseal F, Fissurit FX, Delton Fs+, Admira Seal). During a 14week-long observation, all the materials showed a relatively constant level of F- release; however, it is crucial to mention that within the first 48 h, the most significant increase in fluoride release was found for Fissurit and Delton sealants. Based on the overall assessment, the highest total amount of the released fluoride ions was observed for Delton, and the lowest level was reported for Admira Seal. © 2017 Elsevier GmbH. All rights reserved.
1. Introduction The intensity of the cariostatic action of fluoride ions can be attributed to their multidirectional influence on the caries process [1–5]. Starting from their endogenous activity impacting hard dental tissues in the mineralization period, to external protection in the oral cavity environment, they are an irreplaceable factor that helps sustain mineral balance of the teeth. As a result of concentrating in the dental plaque and constant dissociation from the saliva, they show considerable potential for inhibiting the demineralization processes by supporting the remineralization processes. They stimulate restoration of apatites, and they reduce loss of calcium ions from the enamel surface which is connected with the activity of acids present in oral cavity environment. The mechanisms of the preventive action of fluoride are various [1,4–6]. Fluorides react with hydroxyapatites of the enamel by replacing hydroxide ions. As a result of this reaction, some of the hydroxyapatites transform into fluorapatites which have better crystalline properties, and are more acid-resistant. In the apatite, strong ionic bonds between fluoride and the NH group
∗ Corresponding author. E-mail address: [email protected] (M. Janeczek). http://dx.doi.org/10.1016/j.jtemb.2017.02.014 0946-672X/© 2017 Elsevier GmbH. All rights reserved.
of the organic enamel matrix are formed, which contributes to greater stability of fluorapatite crystals. Fluoride may also react with apatite by stimulating the growth of fluorapatite crystals, as well as it may cause apatite dissolution and forming calcium fluoride. The formation and stimulation of fluorapatite growth may occur during frequent exposure to low fluoride concentration in the solutions (below 0.1%). Many researchers have confirmed the significant role of fissure sealants in the prevention of dental caries in molars and premolars [7–15]. Slow release of the fluoride that they contain has a considerable influence on the intensification of the cariostatic action. 2. Aim The aim of this in vitro study was to determine long-term fluoride release from selected fissure sealants. 3. Material and methods The study involved four fissure sealants (Conseal F, Fissurit FX, Delton Fs+, Admira Seal) which contained the following: • Conseal F (SDI, Australia) – by weight 93% acrylic monomer, 7.0% silica, 0.01% titanium dioxide and 0.01% NaF.
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P. Kosior et al. / Journal of Trace Elements in Medicine and Biology 41 (2017) 107–110
Table 1 Cumulated in vitro F− ion release from fissure sealants into a saline solution (g/mm2 ). Time (hours)
Conseal F (±SD) (g/mm2 )
Fissurit FX (±SD) (g/mm2 )
Delton FS+ (±SD) (g/mm2 )
Admira Seal (±SD) (g/mm2 )
1 3 24 48 72 168 336 504 672 840 1008 1176 1344 1512 1680 1848 2016 2184 2352 Correlation coefficient
1.25 (±0.04) 2.98 (±0.9) 5.31 (±1.46) 6.58 (±1.94) 7.74 (±2.14) 9.39 (±2.17) 11.13 (±2.2) 12.97 (±2.27) 14.97 (±2.62) 17 (±2.92) 17.48 (±2.97) 17.92 (±2.93) 18.22 (±2.92) 18.77 (±2.85) 19.01 (±2.73) 19.13 (±2.75) 19.15 (±2.75) 19.23 (±2.79) 19.83 (±2.8) 0.8925
4.04 (±0.21) 5.78 (±0.5) 8.08 (±1.28) 9.18 (±1.56) 9.75 (±1.7) 11.04 (±2.1) 12.19 (±2.35) 12.92 (±2.33) 14.42 (±2.07) 15.64 (±2.01) 16.84 (±2.47) 18 (±2.73) 19.17 (±2.98) 20.43 (±3.15) 21.59 (±3.14) 22.83 (±3.14) 24.13 (±3.15) 25.58 (±3.09) 28.08 (±3.1) 0.982
3.8 (±0.69) 5.21 (±0.96) 11.4 (±3.16) 14.93 (±3.96) 18.11 (±4.87) 23.93 (±4.84) 29.44 (±6.16) 31.55 (±6.83) 34.2 (±7.7) 36.16 (±7.96) 37.83 (±7.97) 39.62 (±7.98) 41.86 (±8.41) 44.78 (±7.96) 46.48 (±8.1) 48.33 (±8.51) 51.93 (±9.49) 55.81 (±10.67) 61.91 (±12.07) 0.9531
0.19 (±0.02) 0.52 (±0.32) 0.65 (±0.3) 0.76 (±0.31) 0.88 (±0.25) 0.99 (±0.23) 1.27 (±0.21) 1.36 (±0.21) 2.55 (±0.27) 2.92 (±0.25) 3.28 (±0.24) 3.74 (±0.23) 4.25 (±0.25) 4.66 (±0.25) 5.28 (±0.3) 5.87 (±0.34) 6.34 (±0.37) 6.83 (±0.42) 7.36 (±0.3) 0.9971
T-test for two variables Admira Seal Delton FS+ Fissurit FX Conseal
0.0000 0.0000 0.0009 xxx
0.0000 0.0000 xxx
0.0000 xxx
xxx
Friedman’s ANOVA and Kendall’s Coefficient of Concordance. Chi 2 ANOVA (N = 19, df 3) = 50.55789 p 0.00000. Coefficient of Concordance = 0.88698 r average range = 0.88070.
• Fissurit FX (Voco, Germany) – composed of a monomer matrix which consists of methacrylic acid ester (BIS-GMA) and urethane dimethacrylate (around 99%) and a filler – borosilicate glass with the particle size above 1 m (99%), and 3% NaF which corresponds to1.3% fluoride content. • Delton FS+ – it contains two sources of fluoride, by volume 55% of the filler. • Admira Seal – mainly composed of borosilicate glass (16%). The release of fluoride ions from the aforementioned materials to a saline solution was examined for 14 weeks (i.e. 98 days or 2352 h). Samples of the studied materials were formed as cylinders with the use of a polyethylene matrix. The polymerization of a material was conducted according to the recommendations of the manufacturer. After the samples have been hardened, they were polished and their contact surface was calculated in mm2 . Samples were then immersed in the examined solution and left undisturbed in closed containers at the temperature of 37 ◦ C (oral cavity conditions) for a period of time necessary for measurements of the level of fluoride release from the materials. Three samples were made for each material. The ion selective ORION electrode model 9609, and a microcomputer pH/ionometer CPI- 551 Elmetron were used for measurements. The system was calibrated before every examination. Each sample was examined three times, and an average value was calculated based on the three results. The results were collected after 1 and 3 h, next after 1, 2, and 3 days, and then at weekly intervals for 14 consecutive weeks. For individual measurements series, the average as well as the standard deviation of average were calculated. Obtained results of cumulated content of fluorine ions in saline solution were statistically analyzed using Friedman test for repeated data as well as T-student test for dependent data. Coefficient of Pearson’s line correlation between cumulated concentration of fluoride ions and exposure time of the material in saline solution were also calculated. Results of fluoride ions concentration at each time-point were analyzed statistically using of T-student test for dependent data.
All the calculations were performed for the level of significance p < 0,05.
4. Results The levels of fluoride release from the samples of fissure sealants into a saline solution are shown in Table 1 and on Fig. 1. The highest cumulated level of ion release was demonstrated by Delton FS+ (61.91 ± 12.07 g F/mm2 ), and a lower on by Fissurit FX (28.08 ± 3.10 g F/mm2 ), Conseal F (19.83 ± 2.80 g F/mm2 ) and Admira Seal (7.36 ± 0.30 g F/mm2 ) respectively. Extended time of the materials remaining in the saline solution equaled a higher level of released fluorides. All the examined materials showed the highest rate of emission after 1 h; the highest rate was demonstrated by Fissurit FX (4.0400 g F/mm2 /h.), lower by Delton FS+ (3.800 g F/mm2 /h.) and Admira Seal (0.1900 F/mm2 /h.), and the lowest by Conseal (1.2500 g F/mm2 /h.). The rate of fluoride release for all the materials within the following 2 h decreased; the smallest decrease was observed for Admira Seal (of 13%), and the largest for Delton FS+ (of 81%) (Table 2).
5. Discussion The antibacterial activity of fluoride is visible in local concentrations ranging from 0.16 to 0.31 mol/l. In normal conditions, lower amounts of fluoride are observed in the dental plaque [16]. However, it has been demonstrated that low concentrations (around 1 mmol/l) may effectively inhibit the production of bacterial acids, and at the same time, reduce the demineralization of the tooth surface [4,17]. Most of the research conducted so far on fluoride release from dental materials is inconclusive with regards to the solution the measurements should be taken in. The diversity of environments used for taking the measurements is to show their influence on the release level and the significance of the differences [1].
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Fig. 1. Cumulated in vitro F− ion release from fissure sealants into a saline solution (g/mm2 ).
Table 2 Hourly in vitro increments of F− ions release from fissure sealants into a saline solution (g/mm2 ). Increments/h Time (hour)
Conseal (g/mm2 )
Fissurit FX (g/mm2 )
Delton FS+ (g/mm2 )
Admira Seal (g/mm2 )
1 3 24 48 72 168 336 504 672 840 1008 1176 1344 1512 1680 1848 2016 2184 2352 Average Standard Deviation
1.2500 0.8650 0.1109 0.0529 0.0483 0.0171 0.0103 0.0109 0.0110 0.0120 0.0028 0.0026 0.0017 0.0032 0.0014 0.0007 0.0001 0.0008 0.0035 0.1266 0.3353
4.0400 0.8700 0.1095 0.0458 0.0237 0.0134 0.0068 0.0043 0.0089 0.0072 0.0071 0.0069 0.0069 0.0075 0.0069 0.0073 0.0077 0.0086 0.0148 0.2738 0.9330
3.8000 0.7050 0.2947 0.1470 0.1325 0.0606 0.0328 0.0125 0.0157 0.0116 0.0099 0.0106 0.0133 0.0173 0.0101 0.0110 0.0214 0.0231 0.0363 0.2824 0.8678
0.1900 0.1650 0.0061 0.0045 0.0050 0.0011 0.0016 0.0005 0.0070 0.0022 0.0024 0.0027 0.0030 0.0024 0.0036 0.0035 0.0028 0.0029 0.0031 0.0215 0.0551
T-test for two variables Admira Seal Delton FS+ Fissurit FX Conseal F
0.1202 0.2595 0.3292 xxx
0.2302 0.6824 xxx
0.1834 xxx
xxx
The manufacturers of electrodes (e.g. the Orion electrode) used for recording such measurements usually recommend the use of deionized water; however, it is the saline solution that seems to be the most neutral environment that reflects the isotonicity of our organism [1,2]. Deionized water does not always prove to be the best model solution. Thanks to the ionic strength, which is crucial in the process of fluoride ions release and their measurements, saline appears to be a more appropriate option [1–3]. The basic aim of applying fissure sealants is long-term protection of pits and fissures against the development of dental caries [1–6,12,18,19].
The fissure sealants include materials based on glass ionomer cement as well as materials based on Bis-GMA resin. Glass ionomer cement materials demonstrate low retention and low resistance to abrasion and wear, and their anti-cariogenic properties can be attributed to long-term release of fluoride [4,15,18–21]. Bis-GMA resin based materials release less fluoride, and they demonstrate much higher adhesion to the enamel, which guarantees their long clinical retention [4,7,19]. Currently, they are the most commonly used for caries prevention.
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On the market, there are many fissure sealant products available; practically every manufacturer offers such a material. Due to the frequency of clinical application, composite based materials were examined, including Conseal (SDI), Fissurit FX (Voco), Delton FS+ (Johnson&Johnson), and Admira Seal (Voco) based on the ormocer technology. Long-term observation of the fluoride release from the examined materials shows similar properties in this respect. Nevertheless, it is crucial to emphasize that there are differences in terms of the total amount of the released fluoride. 6. Conclusions According to modern guidelines of scientific societies on caries prevention, long release of fluoride in low concentrations is superior to high-dose released in a short time [22]. In our research during the 14-week-long observation, all the materials showed a relatively constant F− release level. It is important to point out that the highest release increase within the first 48 h was observed for the Fissurit FX and Delton FX+ sealants. Based on the overall assessment, the highest total amount of the released fluoride ions was observed for Delton FX+ which may reveal the highest cariostatic effectiveness comparing to other examined fissure sealants. Conflict of interests The authors declare that there is no conflict of interests regarding the publication of this paper. References [1] P. Kosior, Fluoride Release from Selected Dental Materials in Experimental and Clinical Conditions, Wroclaw Medical University, 2005 (Doctorial Thesis). [2] P. Kosior, U. Kaczmarek, Release of fluoride ions into saliva from some dental materials, Ann. Acad. Med. Stetin. 50 (2004) 62–64. [3] P. Kosior, U. Kaczmarek, Effect in vitro of environmental parameters on the release of fluoride ions from some materials used in dentistry, Ann. Acad. Med. Stetin. 50 (2004) 65–68. [4] N. Beiruti, M.A. Frencken, M.A. van’t Hof, W.H. van Palenstein Helderman, Caries preventive effect of resin-based and glass ionomer sealants over time: a systemic review, Community Dent. Oral Epidemiol. 34 (2006) 403–409. [5] A. Ahovou-Saloranta, H. Forss, T. Walsh, A. Hiiri, A. Nordblad, M. Makela, et al., Sealants for preventing dental decay in the permanent teeth, Cochrane Database Syst. Rev. 28 (2013) CD0018303.
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