Self-applied VS professional-applied fluoride: their effects on remineralization of artificial incipient proximal caries in situ Chutima Trairatvorakul, Suthida Vanitchanon, O raphan R ungrojwittayakul, Sunsiree Intaraphueak Department of Pediatric Dentistry, Faculty of Dentistry, Chulalongkorn University, Thailand ABSTRACT Objectives: To compare the effectiveness of self-applied fluoride (5000 ppm NaF gel, 1000 ppm SnF 2 gel, 226 ppm NaF rinse) and professional-applied fluoride(resin-modified glass ionomer cement; ProSeal) on remineralization of artificial incipient carious lesion on proximal surfaces. Methods: Two volunteers wore palatal appliances attached with six slabs of artificial proximal lesion, applied with one of the 4 materials on one side of the appliance comparing to intraoral control on the contralateral side. Every volunteer was randomly assigned to each of the 4 materials. All self-applied fluoride products were applied by the volunteers, while ProSeal was applied by a dentist before their attachment. The fluoride dentifrice was used for 3 minutes twice a day. The palatal appliance was dipped in 20% w/w sucrose solution for 5 minutes, 8 times a day, for 2 weeks of the experimental period. The retrieved slabs were sectioned and lesion areas were examined under polarized light microscope and calculated with Image-Pro plus program. Results: The fluoride products yielded less lesion area compared to control (p<0.05, paired t-test), in descending order: NaF rinse, ProSeal, SnF 2 gel, and NaF gel; however, there were no statistically significant differences among the first 3 products. Conclusion: Both self-applied and professional-applied fluoride were effective in reduction of the proximal carious lesion area, as follows: NaF gel-7.19%, SnF 2 gel-21.52%, NaF rinse-23.52%, and ProSeal-21.89%, in addition to 27.85% reduction from the use of fluoride dentifrice alone. Keywords: professional-applied fluoride; proximal caries; remineralization; self-applied fluoride Received June 2, 2009, Accepted August 26, 2009 Corresponding author's e-mail: ctrairat@gmail.com (Chutima Trairatvorakul) This study was supported by Dental Research Fund, Dental Research Project 3205-312, Faculty of Dentistry, Chulalongkorn University. The authors gratefully acknowledge Ms. Paipun Phitayanon for statistical analysis advices. - 197 -
International Journal of Clinical Preventive Dentistry. 2009, Volume 5, Number 3 1. Introduction Proximal caries is still a major dental health problem(1). Although the decline in dental caries prevalence has been explained by the widespread use of fluoride(2). proximal caries is still prevalent in high risk patients. Besides oral hygiene control, topical fluoride is being used to reverse the progression of caries which may be applied by dentist such as fluoride varnish, fluoride releasing material; glass ionomer cement and resin-modified glass ionomer, while another alternative is self-applied fluoride which is easy to use, and relatively inexpensive such as fluoride mouthrinse, fluoride gel and fluoride dentifrice. Topical fluoride works mainly through three mechanisms; inhibition of demineralization, enhancement of remineralization and inhibition of bacterial enzymes(3). Simple and effective self-applied fluoride agent would be daily rinsing, and it has been found that fluoride applied as a mouthrinse has a marked cariostatic effect, even at poorly accessible locations(4). NaF rinse was reported to yield significantly greater remineralization effects on proximal caries than fluoridated dentifrice and GICs(5). Stannous fluoride gel has been shown to be effective antimicrobial agents, especially against Streptococcus mutans(6). In addition, effectiveness in reducing gingivitis of SnF 2 gel has been reported(7). NaF rinse or SnF 2 gel provided additional protection against decalcification beyond that achieved with fluoride toothpaste alone, but there was no significant difference between them(8). Clinical study found reversal of primary root caries was significantly improved using dentifrices containing 5000 ppm fluoride. Furthermore, a reduced plaque index was observed in the 5000 ppm fluoride group when compared with the 1100 ppm fluoride group(9). The restorative materials containing fluoride used at present is glass ionomer cement(gic) and resin-modified glass ionomer cement(rmgi). Glass ionomer cement appeared to promote a remineralization effect, not only around the restoration margins, but also to the adjacent tooth(10). RMGIC is being used widely because its ability of recharging fluoride and then releasing it, acting as a fluoride pump. A RMGIC, ProSeal(Reliance Orthodontic products, Itasca, Ill), has been developed to improve mechanical properties by adding highly filled light-cured resin. Reduction of the prevalence of decalcification and white-spot lesion have been shown in vitro study(11). Even with a severe acid challenge, ProSeal results in a significant reduction of enamel demineralization in vitro(12). Many in vitro and in vivo studies have been carried out to define the optimal fluoride therapy for the prevention of caries. However, among NaF rinse, NaF gel, SnF 2 gel and resin-modified glass ionomer cement(rmgic), no literature has indicated which preparation is more effective in enhancing remineralization. The purpose of this study was to compare the effectiveness of self-applied NaF rinse, NaF gel, SnF 2 gel and professional-applied resin-modified glass ionomer cement on remineralization of artificial incipient proximal caries in situ. 2.1. Subject 2. Materials and methods Two volunteers, ranging in age from 20 to 21 years old, participated in this study. Each volunteer has normal salivary flow rate(more than 0.1 ml/min) and did not have any systemic, periodontal disease, use any antibiotics, or erosive drugs within the past 30 days, except the fluoride dentifrice used before the study. The procedures of preparation and data collection were carried out at Chulalongkorn University. 2.2. Methods 2.2.1. Tooth Selection and Preparation Twelve molars, free from macroscopic defect, white spot or staining on the proximal surface, were used, which satisfied the requirements of the Chulalongkorn University IRB, and informed patient consent was obtained. The teeth were cleaned with distilled water to remove debris, stored in saline solution to prevent dehydration, and subsequently coated with an acid-resistant nail varnish on all enamel surfaces, except for 5-mm height window across the same level of mesial and distal surfaces that were the targeted areas of the study. Each tooth was sectioned 7 times mesiodistally by a hard-tissue disc(low speed cutting machine, ISOMET 1000, BUEHLER, USA) and then were sectioned buccolingually to divide each tooth into 12 slabs. - 198 -
Self-applied VS professional-applied fluoride: their effects on remineralization of artificial incipient proximal caries in situ Each tooth was divided into 4 quarters of 3 slabs each(figure 1). Each quarter was randomly allocated to an extraoral control, intraoral control and a material-applied slab. Each the four materials were randomly assigned to each of the material-applied slab as follow: Group 1: 0.05%(226 ppm F) NaF mouthrinse(oral-b Tooth and Gum Care Mouth Rinse, Laboratorios Rety De Colombia Retycol S.A., Columbia), Group 2: 0.4%(1000 ppm F) SnF 2 gel(gel-kam, Colgate Oral Pharmaceuticals Inc., Dallas, USA), Group 3: 1.1%(5000 ppm F) NaF gel(prevident GEL, Colgate Oral Pharmaceuticals, Inc., NY, USA) Group 4: RMGI; ProSeal(Reliance Orthodontic products, Itasca, Ill, USA) Removable maxillary acrylic palatal appliances were fabricated for 2 volunteers. Recesses large enough to accommodate up to 6 slabs each were cut into the right and left side of each appliance. Six slabs were mounted laterally to mimic proximal caries on the left or right recess of the appliance. Each slab consisted of 5, one-millimeter windows, the top and bottom windows along with lateral borders of the slabs were applied with flowable composite resin(filtek, 3M, St. Paul, MN) to attach the slabs to the appliance. At the end of the study, there were 36 windows in each of the material group, extraoral control and intraoral control group. The appliances were worn for 14 days in each session with a one-week wash-out period of fluoride dentifrice brushing in between the four sessions. The extraoral control group was stored in deionized water(figure 2) Figure 2. Artificial caries slabs allocated as extraoral control group were kept in deionized water. Intraoral control and material-applied groups were attached to the contra-lateral sides of the palatal appliance Figure 1. Three slabs from each distal or mesial quarter were allocated as extraoral control, intraoral control, and material-applied groups 2.2.2. Formation of Artificial Caries-like Lesion Additional acid-resistant nail varnish was applied to all the exposed surfaces of slabs except the enamel targeted area. To create carious lesion, we immersed the slabs in an artificial caries system for 14 days at 37?C. Each slab was exposed to 5 ml of demineralization solution containing 1% carbopol and 1.0 mol/l lactic acid, to create white-spot lesions approximately 100-150 μm in depth. 2.2.3. Construction of Removable Intraoral Appliance 2.2.4. Intraoral Procedure The volunteers first brushed their teeth with fluoride-containing dentifrice(1100 ppm fluoride, Colgate Total Mint Stripe Gel, Colgate-Palmolive(Thailand) Company) for 7 days before each experimental session. Then, they wore removable palatal appliances for 14 days, except during eating, drinking, carrying out oral hygiene procedures, and bedtime. To provide similar intraoral condition of each session, the palatal appliance was removed and immersed in 20% w/w sucrose solution for 5 minutes, 8x/day(7.30am, 12.00pm, 4.00pm, 6.30pm, 7.00pm, 8.00pm, 9.00pm, and 10.00 pm). During the volunteers' habitual oral hygiene routine, 2x/day(6.00am and 10.30pm), the appliance was removed then the volunteers brushed their natural teeth for 1 minute - 199 -
International Journal of Clinical Preventive Dentistry. 2009, Volume 5, Number 3 30 seconds and tissue surface area of the appliances for 30 seconds and re-inserted the appliance into the mouth to let the slabs immerse in fluoride foam from dentifrice for 1 minute. Then, the palatal appliance was removed and rinsed with 15 ml of water. The volunteer spit the fluoride foam and rinsed his/her mouth with 15 ml of water. Every volunteer was randomly assigned to each of the treatments. Each time after their oral hygiene routine, the volunteer, who was randomly assigned to NaF mouthrinse group, removed the appliance and immersed only the experimental-side slabs for 1 minute, 2x/day. For the SnF 2 gel and NaF gel groups, both gels were applied to experimental-side of slabs for 1 minute, 1x/day, and for ProSeal group, ProSeal was applied on the tested surfaces of the slabs on the first day of the experimental period prior to being attached to the palatal appliance. Before bedtime, the appliance was removed and covered by cotton soaked with 10-mL artificial saliva in a plastic box. 2.2.5. Embedding of Slabs After 14-day experimental period, the appliance was removed and the slabs were retrieved out of the appliance. All remaining acid-resistant nail varnish was removed with acetone solvent for better retention between acrylic resin and the enamel surface. To prepare sample slabs for viewing under the microscope. Each slab was fixed with wax to the base of a cylindrical mould(2 cm. diameter and 3 cm. height) in the upright manner such that its long axis was perpendicular to the base of the mould. Then, clear epoxy resin was poured into the mould and allowed to set at room temperature(25 C) for 24 hours, after which the blocks were cross-sectioned mesiodistally with a Saw Microtome(LEICA SP 1600, Nussloch, Germany) to obtain thin sections approximately 100 microns thick. 2.2.6. Assessment of Lesion Area The sections were imbibed with deionized water and examined under polarized light microscopy(9300 MEIJI, Saitama, Japan) at 40x magnification. The images were captured with digital camera(axio Camera MRc5, ZEISS, Germany) and then transferred to be adjusted with 100% contrast by Adobe Photoshop CS version 8.0. The lesion area was measured using Image Pro-plus program version 4.05(Media Cybernetics Inc., Silver Spring, MD, USA)(figure 3). Figure 3. The carious lesions were examined under polarized light microscope at 40x magnification. 2.2.7. Statistical Analysis Statistical analysis was performed with two programs; SPSS version 16.0 and SigmaStat version 2.03. Mean values of the lesion area were checked for a normal distribution by Kolmogorov-Smirnov test. To prove whether there were no statistically significant difference within extraoral control groups, intraoral control groups, one way repeated analysis of variance was used. The differences between intraoral control groups and material applied groups were calculated using paired t-test. A post-hoc Duncan multiple comparison test was used to determine the statistically significant differences between the treatments. A 95% significant level was used in this study. 3. Results No statistically significant differences in lesion area were found within extraoral control groups and among the intraoral control groups of each experimental session, thus the assumption can be made that the initial lesion area of all the experiments were similar and each lesion was exposed to similar oral condition equally. Therefore, all results could be compared. However, the intraoral control groups showed significant reduction of lesion area comparing to extraoral control group(p<0.05) as shown in table 1. This implied that the use of fluoride dentifrice could reduce the carious lesion area to approximately 27.85%. This study showed statistically significant differences in remineralization effects in all four materials(p<0.05) comparing to intraoral control, indicating a percentage of - 200 -
Self-applied VS professional-applied fluoride: their effects on remineralization of artificial incipient proximal caries in situ Table 1. Mean of lesion area+sd(mm 2 ) of extra and intra-oral control groups Mean of lesion area ± SD(mm 2 ) Extraoral control Intraoral control Percentage of reduction NaF gel 0.091 ± 0.035 * 0.070 ± 0.024 27.85% SnF 2 gel 0.092 ± 0.033 * 0.064 ± 0.013 NaF rinse 0.093 ± 0.033 * 0.060 ± 0.015 ProSeal 0.077 ± 0.024 * 0.060 ± 0.023 * : statistically significant reduction compared with the extraoral control group(p<0.05; paired t-test) Table 2. Mean of lesion area+sd(mm 2 ) and percentage of reduction between intraoral control group and material applied group Mean of lesion area ± SD(mm 2 ) Percentage of reduction Intraoral control Material applied NaF gel 0.070 ± 0.024 * 0.059 ± 0.022 a 7.19 SnF 2 gel 0.064 ± 0.013 NaF rinse 0.060 ± 0.015 * 0.050 ± 0.014 b 21.52 * 0.049 ± 0.016 b 23.52 ProSeal 0.060 ± 0.023 * 0.050 ± 0.011 b 21.89 * : statistically significantly reduction compared with the intraoral control group(p<0.05; paired t-test) a,b : Different letters in each column indicate statistically significant among groups(p<0.05, Duncan s test) reduction in lesion area of 7.19%, 21.52%, 23.52%, and 21.89% for the NaF gel, SnF 2 gel, NaF rinse, and ProSeal groups, respectively, in addition to the 27.85% reduction from the use of fluoride dentifrice alone. Duncan's analysis indicated NaF rinse to have the greatest evidence of reduction followed by ProSeal, SnF 2 gel, and NaF gel. However, there was no statistically significant difference among NaF rinse, ProSeal, and SnF 2 gel, as shown in table 2. 4. Discussion The purpose of this study was to compare the effectiveness of self-applied fluoride(5000 ppm NaF gel, 1000 ppm SnF 2 gel, and 226 ppm NaF rinse) and professional-applied fluoride(resin-modified glass ionomer cement; ProSeal) on the remineralization of artificial incipient carious lesion on proximal surfaces. From the data obtained, it was found that NaF rinse yielded the highest percentage of reduction, comparing to ProSeal, SnF 2 gel, and NaF gel, respectively, as shown in table 2. This may be because NaF mouthrinse has much more penetrating ability into the interproximal area than other materials(5, 13) due to liquid property, which carried fluoride ion(f-) to the enamel surface efficiently. Moreover, the NaF rinse used in our study contained 0.05% cetylpyridinium chloride with additional plaque controlling ability commonly found in the mouthrinse commercial products. This is consistent with a previous study that mouthrinse containing 0.05% cetylpyridinium chloride had the efficacy of controlling supragingival plaque and gingivitis(14). In addition, low concentration and high frequency is the major concept for mouthrinse in remineralization of the white spot lesion and considered to protect enamel from demineralization even in a low ph environment(15). Our results agreed with Boyd's study on which SnF 2 gel used 2x/day and NaF rinse 1x/day yielded similar result between the two products despite the fact that the frequency is different from our in situ study. They measured decalcification on the facial surfaces of orthodontic patients with various classifications of score. Their study took approximately two years 8. ProSeal and fluoride gel are considered to be an effective approach for incipient caries lesion. In this study, ProSeal yielded greater reduction than fluoride gel. The reason may be that ProSeal constantly released fluoride in amount of 0.074±0.04 ppm/week/mm 2 and 0.067±0.075 ppm/week/mm 2 in the first and second week, respectively, as reported in the in vitro study(16). This low-dose fluoride is effective in enamel remineralization capabilities. Owing to the induced high-caries risk condition in our in situ study, plaque-associated organic acids may increase initial fluoride release(17). ProSeal is recommended rather than both - 201 -
International Journal of Clinical Preventive Dentistry. 2009, Volume 5, Number 3 mouthrinse and gel when there are problems associated with patient compliance. Comparing SnF 2 gel to NaF gel, SnF 2 gel is more efficient, because of its antimicrobial activity which considered to be an important factor in our study due to high caries challenge condition, even though SnF 2 contained lower fluoride concentration than NaF gel. The mechanism of antimicrobial activity was explained by a tin-fluoride-phosphate reaction complex which was derived from SnF 2 gel. This complex made SnF 2 -treated enamel more difficult to be colonized than NaF-treated enamel 6. The antibacterial property from both the NaF rinse used in this study and the SnF 2 gel may contribute to their higher efficacy in decreasing the lesion depths, comparing to the NaF gel. As previous study, fluoride dentifrice is one of the most effective cariostatic products when used as a daily fluoride application(18). Therefore, it is not surprising that the intraoral control had less lesion area than extraoral control since volunteers used fluoride dentifrice during the study. Our study also indicated that using fluoride dentifrice together with either self-applied fluoride(naf gel, SnF 2 gel, and NaF rinse) or professional-applied fluoride(proseal) provides additional enhancing remineralization beyond that achieved with fluoride dentifrice alone. Even though, nowadays there are many effective topical-fluoride products, the choice of either professional or self used fluoride for each patient depends on many factors such as, age, education, oral health habit, physical dexterity, compliance and cost/benefit ratio of the whole approach. It should be noted that our study only showed 2-week effect of fluoride-containing material. Future long-term effects should be investigated to find the most effective products. 5. Conclusion Both self-applied fluoride(5000 ppm NaF gel, 1000 ppm SnF 2 gel, and 226 ppm NaF rinse) and professional-applied fluoride(proseal) were effective in remineralization of incipient carious lesion. NaF rinse yielded the greatest percent reduction of lesion area followed by ProSeal, SnF 2 gel, and NaF gel; however, there was no statistically significant difference among NaF rinse, ProSeal, and SnF 2 gel. References 1. Mejare I, Kallestal C, Stenlund H, Johansson H. Caries development from 11 to 22 years of age: a prospective radiographic study. Prevalence and distribution. Caries Res. 1998;32(1):10-6. 2. Paes Leme AF, Dalcico R, Tabchoury CP, Del Bel Cury AA, Rosalen PL, Cury IA. In situ effect of frequent sucrose exposure on enamel demineralization and on plaque composition after APF application and F dentifrice use. J Dent Res. 2004 Jan; 83(1):71-5. 3. Featherstone JD. The science and practice of caries prevention. J Am Dent Assoc. 2000 Jul;131(7):887-99. 4. Ogaard B, Arends J, Schuthof J, Rolla G, Ekstrand J, Oliveby A. Action of fluoride on initiation of early enamel caries in vivo. A microradiographical investigation. Caries Res. 1986;20(3):270-7. 5. Marinelli CB, Donly KJ, Wefel JS, Jakobsen JR, Denehy GE. An in vitro comparison of three fluoride regimens on enamel remineralization. Caries Res. 1997;31(6):418-22. 6. Tinanoff N, Brady JM, Gross A. The effect of NaF and SnF 2 mouthrinses on bacterial colonization of tooth enamel: TEM and SEM studies. Caries Res. 1976;10(6):415-26. 7. Boyd RL, Leggott PJ, Robertson PB. Effects on gingivitis of two different 0.4% SnF 2 gels. J Dent Res. 1988 Feb;67(2):503-7. 8. Boyd RL. Comparison of three self-applied topical fluoride preparations for control of decalcification. Angle Orthod. 1993 Spring;63(1):25-30. 9. Baysan A, Lynch E, Ellwood R, Davies R, Petersson L, Borsboom P. Reversal of primary root caries using dentifrices containing 5,000 and 1,100 ppm fluoride. Caries Res. 2001 Jan-Feb;35(1):41-6. 10. Jang KT, Garcia-Godoy F, Donly KJ, Segura A. Remineralizing effects of glass ionomer restorations on adjacent interproximal caries. ASDC J Dent Child. 2001 Mar-Apr;68(2):125-8, 42. 11. Salar DV, Garcia-Godoy F, Flaitz CM, Hicks MJ. Potential inhibition of demineralization in vitro by fluoride-releasing sealants. J Am Dent Assoc. 2007 Apr;138(4):502-6. 12. Hu W, Featherstone JD. Prevention of enamel demineralization: an in-vitro study using light-cured filled - 202 -
Self-applied VS professional-applied fluoride: their effects on remineralization of artificial incipient proximal caries in situ sealant. Am J Orthod Dentofacial Orthop. 2005 Nov;128(5):592-600; quiz 70. 13. Altenburger MJ, Schirrmeister JF, Wrbas KT, Hellwig E. Remineralization of artificial interproximal carious lesions using a fluoride mouthrinse. Am J Dent. 2007 Dec;20(6):385-9. 14. Allen DR, Davies R, Bradshaw B, Ellwood R, Simone AJ, Robinson R, et al. Efficacy of a mouthrinse containing 0.05% cetylpyridinium chloride for the control of plaque and gingivitis: a 6-month clinical study in adults. Compend Contin Educ Dent. 1998;19(2 Suppl):20-6. 15. Inaba D, Kawasaki K, Iijima Y, Taguchi N, Hayashida H, Yoshikawa T, et al. Enamel fluoride uptake from mouthrinse solutions with different NaF concentrations. Community Dent Oral Epidemiol. 2002 Aug;30(4):248-53. 16. Soliman MM, Bishara SE, Wefel J, Heilman J, Warren JJ. Fluoride release rate from an orthodontic sealant and its clinical implications. Angle Orthod. 2006 Mar;76(2):282-8. 17. Behrend B, Geurtsen W. Long-term effects of four extraction media on the fluoride release from four polyacid-modified composite resins(compomers) and one resin-modified glass-ionomer cement. J Biomed Mater Res. 2001;58(6):631-7. 18. Twetman S, Axelsson S, Dahlgren H, Holm AK, Kallestal C, Lagerlof F, et al. Caries-preventive effect of fluoride toothpaste: a systematic review. Acta Odontol Scand. 2003 Dec;61(6):347-55. - 203 -