|Year : 2011 | Volume
| Issue : 3 | Page : 202-204
Fluoride rechargability of a non-resin auto-cured glass ionomer cement from a fluoridated dentifrice: An in vitro study
A Rao, A Rao, P Sudha
Department of Pedodontics, Manipal College of Dental Sciences, Mangalore, Manipal University, India
|Date of Web Publication||10-Oct-2011|
Department of Pedodontics, "Seetha", 1-34-3071/3, Ashoknagar, Mangalore - 575 006
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: In addition to their fluoride-releasing properties, glass ionomer cement (GICs) have the ability to reuptake and release fluorides from commonly used sources like fluoridated dentifrices. This property has the potential to provide a continuous low concentration of fluoride in the saliva aiding in caries prevention. The superior fluoride-recharging abilities of resin-modified GICs over conventional GICs have been documented. The manufacturer of a non-resin, auto-cured GIC (GC Fuji VII) claims fluoride release from the product to be about six times that of conventional GIC. It was hypothesized that perhaps this high fluoride release could translate into a high reuptake and release, when exposed to a 1 000 ppm fluoridated dentifrice every day, thus providing increased fluoride levels in saliva. Aims: This study therefore examined fluoride-recharging abilities of the non-resin, auto-cured glass ionomer cement from a 1 000 ppm fluoridated dentifrice and compared it with resin-modified glass ionomer cement. Materials and Methods: Twelve glass ionomer discs each of resin-modified glass ionomer cement (GC Fuji II L C, Group 1) and the non-resin, auto-cured glass ionomer cement (GC Fuji VII, Group 2) were prepared with precise dimensions of 9 x 2 mm. The 12 specimens in each group were further subdivided into two subgroups of six each. Subgroup A involved no fluoride treatment (Control). Subgroup B involved application of a 1 000 ppm dentifrice for 2 minutes twice daily with a soft toothbrush. The disc-specimens were then suspended in airtight plastic bottles containing exactly 20 ml double distilled water. The fluoride concentration of the water in which the specimen discs were immersed was measured by means of a fluoride ion selective electrode connected to an ion selective electrode meter/digital ion analyzer at 1, 2, 7, 15, and 30 days. Statistical Analysis: It was performed using the Kruskal-Wallis Test. Results and Conclusion: Fuji VII, despite a high fluoride release, did not significantly recharge when exposed to a 1 000 ppm fluoridated dentifrice.
Keywords: Fluoride rechargability, fluoridated dentifrice, glass ionomer cement
|How to cite this article:|
Rao A, Rao A, Sudha P. Fluoride rechargability of a non-resin auto-cured glass ionomer cement from a fluoridated dentifrice: An in vitro study. J Indian Soc Pedod Prev Dent 2011;29:202-4
|How to cite this URL:|
Rao A, Rao A, Sudha P. Fluoride rechargability of a non-resin auto-cured glass ionomer cement from a fluoridated dentifrice: An in vitro study. J Indian Soc Pedod Prev Dent [serial online] 2011 [cited 2015 Apr 25];29:202-4. Available from: http://www.jisppd.com/text.asp?2011/29/3/202/85812
| Introduction|| |
The fluoride-releasing ability of glass ionomer cements can result in an anticariogenic effect  and an increased resistance to secondary caries.  In addition, glass ionomer cement (GICs) have the ability to replenish fluoride from outside sources and release it back to the oral environment. , The resultant low concentration of fluoride can aid in the remineralizing actions of saliva. ,
Fluoridated dentifrices are the most common source of fluorides used on an everyday basis. GIC reuptake abilities from toothpastes have been established from previous studies.  The superior fluoride-recharging patterns of resin-modified GICs from fluoridated dentifrices have already been studied.  The manufacturer of a non-resin, auto-cured GIC (GC Fuji VII) claims fluoride release from the product to be about six times that of conventional GIC. , So, it was hypothesized that perhaps this high fluoride release could translate into a high reuptake and release when exposed to a 1 000 ppm fluoridated dentifrice every day, thus providing increased fluoride levels in saliva.
Therefore, the present study was conducted to evaluate fluoride rechargability of a non-resin, auto-cured GIC from a 1 000 ppm fluoridated dentifrice and compare it with a resin-modified glass ionomer cement.
| Materials and Methods|| |
Twenty-four glass ionomer discs (12 of each group), each with precise dimensions of 9 x 2 mm, were prepared using open-ended cylindrical copper mould [Figure 1]. A dental floss was incorporated into the discs during disc fabrication to allow for suspension into the test medium.
After fluoride treatment, each disc was wiped clean with a tissue, and then thoroughly rinsed by exposing each side to a stream of double distilled water for 20 seconds. Each disc was dried for two minutes on an absorbent paper.
The disc-specimens were then suspended in airtight plastic bottles containing exactly 20 ml double distilled water. The average fluoride concentration of the double distilled water was earlier found to be <0.01 ppm.
The fluoride concentration of the water in which the specimen discs were immersed was measured by means of a fluoride ion selective electrode (ORION model 940900) connected to an ion selective electrode meter/digital ion analyzer (ORION EA -940).
The fluoride electrode is sensitive to changes in pH and so a buffer called as TISAB II (Total Ionic Strength Adjustment Buffer) must be added to any water specimen before testing in order to hold the pH of water between 5.0 and 5.5. The use of TISAB II frees fluoride ions bound to hydrogen and eliminates hydroxyl ion interference, enabling an accurate measurement of the total fluoride content.
Before proceeding with the test, the fluoride electrode had to be calibrated. This was done by using a sodium fluoride stock solution with a concentration of 100 ppm fluoride. This solution was then diluted in stages with double distilled water to produce standard solutions of 20 ppm, 10 ppm, 5 ppm, and 2.5 ppm fluoride.
Fluoride measurements were made at intervals of 1, 2, 7, 15, and 30 days. The electrode was recalibrated at every interval.
Statistical analysis was performed using the Kruskal-Wallis Test. P<0.05 was considered significant. P<0.01 was highly significant and P<0.001 was considered very highly significant.
| Results|| |
Mean (± SD) fluoride release data for each material/fluoride treatment combination at each test interval are shown in [Table 1].
|Table 1: Mean (± SD) fluoride release data for each material/fluoride treatment combination at each test interval|
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Fluoride release from subgroup B (Fluoridated dentifrice) was statistically significant compared with subgroup A (Control) at each of the test intervals in Group 1 (resin-modified GIC).
There was no statistical significance observed in fluoride release between Subgroups A (Control) and B (Fluoridated dentifrice) at each of the test intervals in Group 2 (GC Fuji VII).
| Discussion|| |
"Recharging" is the measure of the difference in fluoride release between the control group and the fluoride treatment group. , The results of the present study suggest that a high fluoride release does not translate into high fluoride rechargability. GC Fuji VII released high amounts of fluoride in the control group. This confirmed manufacturers claim of very high fluoride release from the product. But, surprisingly, Fuji VIIdid not show any significant increase in the fluoride treatment group. Freedman and Diefinderfer  had observed that glass ionomer specimens which received one fluoride exposure released less fluoride compared with specimens which received two exposures. But, there was no significant difference in fluoride release between specimens which received two fluoride and three fluoride exposures. They hypothesized that this may be due to a "saturation effect" where in glass ionomer cement does not uptake more fluoride after one point. The lack of fluoride uptake by GC Fuji VII may also be explained by this hypothesis as they already contain a high inherent concentration of fluoride as demonstrated by their high fluoride release.
In this study, resin-modified glass ionomer cement showed a better ability to reuptake fluoride from a 1 000 ppm fluoridated dentifrice. This confirms previous observations by Freedman and Diefenderfer.  They found that resin-modified glass ionomer cement showed superior rechargability after exposure to a 1 000 ppm fluoridated dentifrice twice daily.
An important point is to be noted here. Despite the inadequate recharging abilities, GC Fuji VII showed a high fluoride release at every test interval compared with resin-modified GIC. Both these materials have different clinical indications. So, they could still play important roles in caries prevention, although with different fluoride releasing and recharging patterns.
| Conclusions|| |
Under the conditions of this study: The fluoride rechargability of GC Fuji VII from a 1 000 ppm fluoridated dentifrice was not significant compared with resin-modified glass ionomer cement.
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