HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J Am Dent Assoc, Vol 132, No 10, 1389-1392. © 2001 American Dental Association

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by CASTILLO, J. L. Articles by FEY, M. Search for Related Content PubMed PubMed Citation Articles by CASTILLO, J. L. Articles by FEY, M. Related Collections Pharmacology

COVER STORY
JADA Continuing Education

	ABSTRACT

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Background. The authors conducted a study to evaluate the fluoride released from two fluoride varnishes: Duraphat (Colgate-Palmolive Co., New York) and Duraflor (Pharmascience Inc., Montreal). Fluoride-release information for these commercially available dental products has not been available to clinicians treating children at risk of developing dental caries.

Methods. The authors painted enamel slabs from primary molar teeth with 30 milligrams of two varnishes: nine samples received Duraphat, nine received Duraflor and five samples served as controls. The samples were immersed in buffered calcium phosphate solution (pH, 6.0) to simulate the oral environment, and the amount of fluoride released was measured weekly for six months.

Results. From week 4 to the end of the study, Duraphat released significantly more fluoride than Duraflor. Duraflor continued releasing fluoride until week 19, while Duraphat released fluoride until week 28. The authors found greater variability in the release of fluoride from the Duraflor samples than from the Duraphat samples. Two-thirds of the fluoride was released from both products by the end of the study.

Conclusions. Both varnishes released fluoride for five to six months. However, the two products exhibited differences in their release kinetics.

Clinical Implications. These findings show that either of the fluoride varnishes may maintain a high level of fluoride in plaque fluid around primary teeth over a long period, but that the availability of fluoride may vary among tubes of the same product and between the two products themselves.

There is ample clinical evidence that biannual applications of fluoride varnish decrease dental caries in primary teeth.^1,2 Repeated applications within a shorter period have been shown to result in greater caries reduction.³ However, none of these studies was conducted in the United States, and the products available here have not been fully evaluated. Fluoride varnish use in the United States is slowly increasing, but the U.S. Food and Drug Administration has approved its use only for sensitive teeth and as a cavity varnish, although its use for caries control has not been contraindicated.⁴ Fluoride varnishes have been shown to inhibit demineralization^5–7 and to promote remineralization of enamel.⁸ The preventive effect of topical fluorides resides in the fluid layer of the plaque.⁹ The efficacy of fluoride varnishes in reducing caries levels also has been attributed to their antibacterial properties.^10,11

Both varnishes released fluoride for five to six months, but the products exhibited differences in release kinetics.

We conducted this study to find out if two fluoride varnishes released fluoride for at least six months and if the products differed in any way.

	MATERIALS AND METHODS

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Test system. We obtained 5- x 5-millimeter primary molar tooth slabs from exfoliated teeth collected in non-fluoridated communities in Lima, Peru. One of us (J.C.) painted them with 30 milligrams of fluoride varnish (35.7 micromole of fluoride). Nine samples were painted with one fluoride varnish (Duraphat, Colgate-Palmolive Co., New York) and nine with a second varnish (Duraflor, Pharmascience Inc., Montreal), and five samples remained as untreated controls. Dr. Castillo painted the samples with varnish obtained from different tubes (that is, nine tubes of Duraphat and nine tubes of Duraflor). Both varnishes contain 5 percent weight sodium fluoride or 2.26 percent fluoride in a neutral colophonium base; they also contain alcohol, shellac, rosin, copal and flavoring.

The samples then were immersed in a buffered calcium phosphate solution (pH, 6.0) at room temperature. Each week, a new test tube was prepared with 20 milliliters of the calcium phosphate solution. We transferred the samples to the new tubes. Daily during the first week and then once weekly thereafter, we measured the concentration of fluoride in the solution to determine the amount of fluoride released by the sample.¹²

Both varnishes maintained low levels of fluoride release over long periods.

Fluoride analysis. One of us (J.C.) calibrated the fluoride electrode (Thermo Orion, Beverly, Mass.)—a device that measures the concentration of fluoride ion in a solution—with total ionic strength adjusting buffer, or TISAB, solution and fluoride standards (that is, a known amount of fluoride solution used in calibrating the electrode). Two fluoride calibration curves were made: one for low levels of fluoride using low-level TISAB and one for high levels of fluoride using TISAB III. On semilogarithmic paper, we plotted the concentration (log axis) of the standards against the millivoltage (linear axis). On each day that measurements were made, a new calibration curve was prepared with fresh standards.

A fluoride analysis was performed to determine the concentration of fluoride in the solution, which is the amount of fluoride released by the tooth sample. Millivoltage was read and converted into micromolar, using the calibration curves described above. An investigator (J.C.) who did not know the product being studied made all of the measurements.

We used quality control samples (25 µmol/L solutions of fluoride) to determine the degree of variability of the electrode. At the end of the study, the quality control samples were compared. The mean (± standard deviation) fluoride concentration in these samples was 23.8 ± 2.0 µmol/L, with a coefficient of variation of 8.15 percent for all measurements, indicating that the results of the study were not influenced by malfunctioning of the electrode.

	RESULTS

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Release of fluoride. Figure 1 illustrates the release of fluoride from both varnish products over six months. The data have been converted into logarithms. Student t-tests for samples with unequal variances were used to examine differences in fluoride release. We found no difference in the mean total amount of fluoride released by the two products at the end of the study (25.1 ± 4.9 µmol for Duraphat and 20.2 ± 14.7 µmol for Duraflor; P = .41). Duraphat released 67 percent of the total fluoride applied and Duraflor released 56 percent of the total fluoride applied.

View larger version (36K): [in this window] [in a new window]   Figure 1. The in vitro release of fluoride from two fluoride varnishes (Duraphat, Colgate-Palmolive Co., New York, and Duraflor, Pharmascience Inc., Montreal) over time after a single application to primary molar teeth.

 
Rate of release. We calculated the mean slope for each of the products from week 1 to week 24. A t-test was used to evaluate significant differences between the slopes. Duraphat had a slope of –0.06 ± 0.01 and Duraflor had a slope of –0.09 ± 0.02 (P < .005) (that is, the rate of decay of fluoride was faster with Duraflor). When the results were separated into two periods, this difference was noted from week 1 to week 3, but the rate of release of fluoride from week 4 to the end of the study was not different for the two varnishes (P < .18).

Variability of the products. We measured the mean total amount of fluoride released by each of the nine samples for both fluoride varnishes (Figure 2). We used the F test for the equality of two variances to compare the variability between both products. The results showed that Duraflor exhibited more variability than did Duraphat (F test for unequal variances, P < .005). The mean amount of fluoride released was 25.1 ± 4.9 µmol for Duraphat and 20.2 ± 14.7 µmol for Duraflor. The range was 18.6 to 33.9 µmol for Duraphat and 3.1 to 46.8 µmol for Duraflor.

View larger version (29K): [in this window] [in a new window]   Figure 2. The variability of total fluoride released in vitro between nine samples that received one fluoride varnish (Duraphat, Colgate-Palmolive Co., New York) and nine samples that received a second fluoride varnish (Duraflor, Pharmascience Inc., Montreal).

 

	DISCUSSION

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Both varnishes maintained low levels of fluoride release over long periods, which is important to clinicians who use the products biannually. The mean absolute level of fluoride released was consistently higher for Duraphat than it was for Duraflor during the six-month evaluation. In the initial three-week period, the rate of release of Duraflor was much greater than that of Duraphat. From then on, the rate of release was similar for both products. We found that the variability of fluoride release of Duraflor was significantly greater than that of Duraphat.

The clinical significance of the absolute levels of fluoride released in this test system remains to be determined. Nevertheless, the amount of fluoride varnish placed clinically is about 595 µmol. We placed 35.7 µmol on a small surface (5 x 5 mm) of primary enamel, which is close to the amount that each tooth would receive clinically.

There are, of course, differences between the experimental model and clinical practice. The amount of fluoride varnish placed clinically is difficult to control. Depending on the mode of application, some varnish may stay on the application brush. In working with young children, dentists may find that moisture control is difficult and the amount adhering to the teeth may vary. In addition, oral functions such as swallowing, chewing and salivation, and mechanical functions such as brushing and flossing are not present on an in vitro model. Thus, clinically, there may be greater variation between patients, and the release of fluoride may be more rapid in a clinical setting.

The amount of fluoride released by Duraflor was greater than the amount released by Duraphat during the first three weeks, but the release level dropped rapidly after that. Duraphat maintained a steady decrease throughout the experimental period. Duraphat seems to be more viscous than Duraflor and tends to dry faster on the tooth, which might explain some of the differences we found. The variation in fluoride release seen within Duraflor samples also may reflect poor quality control.

	CONCLUSION

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Both fluoride varnishes released fluoride in vitro for an extended period, but we found that the mode of release was different for the two products evaluated.

View larger version (127K): [in this window] [in a new window]   At the time this study was conducted, Dr. Castillo was a graduate student, Department of Orthodontics, University of Washington, Seattle. He now is in private orthodontic practice in Lima, Peru.

 

View larger version (135K): [in this window] [in a new window]   Dr. Milgrom is a professor, Department of Dental Public Health Sciences, University of Washington, Suite B509, Box 357475, Seattle, Wash. 98195-7475, e-mail "dfrc{at}u.washington.edu". Address reprint requests to Dr. Milgrom.

 

View larger version (119K): [in this window] [in a new window]   Dr. Kharasch is a professor, Department of Anesthesiology, School of Medicine, University of Washington, Seattle.

 

	FOOTNOTES

Dr. Fey is an affiliate associate professor, Department of Orthodontics, University of Washington, Seattle.

Drs. Milgrom and Kharasch have served as paid consultants to Pharmascience Inc., Montreal, Quebec, Canada.

This article is based on a thesis submitted by Dr. Castillo to the Graduate Faculty, University of Washington, Seattle, in partial fulfillment of the requirements for the Master of Science in Dentistry degree.

The study was supported by the Orthodontic Memorial Fund and grant DE09743 to the Regional Clinical Dental Research Center at the University of Washington, Seattle, from the National Institute of Dental and Craniofacial Research, National Institutes of Health.

The authors acknowledge the assistance of Prof. John D. Featherstone, University of California, San Francisco.

	REFERENCES

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 

1. Murray JJ, Winter GB, Hurst CP. Duraphat fluoride varnish: a 2-year clinical trial in 5-year-old children. Br Dent J 1977;143:11–7.[Medline]
   
   
2. Holm AK. Effect of fluoride varnish (Duraphat) in preschool children. Community Dent Oral Epidemiol 1979;7:241–5.[Medline]
   
   
3. Petersson LG, Arthursson L, Ostberg C, Jonsson G, Gleerup A. Caries-inhibiting effects of different modes of Duraphat varnish reapplication: a 3-year radiographic study. Caries Res 1991;25:70–3.[Medline]
   
   
4. Fiset L, Grembowski D, Del Aguila M. Third-party reimbursement and use of fluoride varnish in adults among general dentists in Washington State. JADA 2000;131:961–8.[Abstract/Free Full Text]
   
   
5. Derand T, Petersson LG. Effect of fluoride varnishes and Nuva-Seal resin treatment on the formation of artificial carious lesions. Caries Res 1981;15:250–5.[Medline]
   
   
6. De Bruyn H, Buskes JA, Arends J. The inhibition of demineralization of human enamel after fluoride varnish application as a function of the fluoride content: an in vitro study under constant composition demineralizing conditions. J Biol Buccale 1986;14:133–8.[Medline]
   
   
7. Sorvari R, Meurman JH, Alakuijala P, Frank RM. Effect of fluoride varnish and solution on enamel erosion in vitro. Caries Res 1994;28:227–32.[Medline]
   
   
8. Sëppa L. Effects of a sodium fluoride solution and a varnish with different fluoride concentrations on enamel remineralization in vitro. Scand J Dent Res 1988;96:304–9.[Medline]
   
   
9. Featherstone JD. The science and practice of caries prevention. JADA 2000;131:887–99.[Abstract/Free Full Text]
   
   
10. Luoma H, Luoma AR. Differences in pH fall, phosphorous content and dissolution of enamel in layers of the oral bacterium Streptococcus mutans deposited in vitro on bovine enamel granules with and without fluoride varnish. Arch Oral Biol 1982;27:1003–6.[Medline]
    
    
11. Zickert I, Emilson CG. Effect of a fluoride-containing varnish on Streptococcus mutans in plaque and saliva. Scand J Dent Res 1982;90:423–8.[Medline]
    
    
12. Featherstone JD, Behrman JM, Bell JE. Effect of whole saliva components on enamel demineralization in vitro. Crit Rev Oral Biol Med 1993;4(3–4):357–62.[Abstract/Free Full Text]
    
    

This article has been cited by other articles:

				C. Trairatvorakul, S. Kladkaew, and S. Songsiripradabboon Active Management of Incipient Caries and Choice of Materials Journal of Dental Research, March 1, 2008; 87(3): 228 - 232. [Abstract] [Full Text] [PDF]

				B. D. HODGSON An alternative technique for applying fluoride varnish J Am Dent Assoc, September 1, 2005; 136(9): 1295 - 1297. [Full Text] [PDF]

				D. M. Smith FLUORIDE VARNISH APPLICATION J Am Dent Assoc, March 1, 2005; 136(3): 278 - 278. [Full Text] [PDF]

				J. L. CASTILLO and P. MILGROM Fluoride release from varnishes in two in vitro protocols J Am Dent Assoc, December 1, 2004; 135(12): 1696 - 1699. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by CASTILLO, J. L. Articles by FEY, M. Search for Related Content PubMed PubMed Citation Articles by CASTILLO, J. L. Articles by FEY, M. Related Collections Pharmacology