Abstract
Objective: Fluoride varnishes are applied for preventing of caries. This study evaluated the effect of fluoride varnish after removing the materials on dentin demineralization in an automatic pH-cycling system.
Methods: Specimen preparation: Six extracted human teeth were prepared. Four 200µm thickness single-sections were obtained from each tooth. The polished surfaces, except the outer surface, were covered with a wax. Two different fluoride varnish (CTX2 Varnish, Oral Biotech (CTX), MI varnish, GC (MI)) and one glass-ionomer cement (Fuji III, GC (F3)) were applied on the root surface. No treated specimens were used as a control (Control). These materials are removed from surfaces after 24 hours. The pH-cycling system (pH6.8-4.5) was carried out for four weeks in four beakers, which have five specimens applied same material, Control, CTX, MI, and F3. After pH-cycling, all specimens were taken transverse microradiography (TMR) and integrated mineral loss (IML) were calculated from TMR images. Data were analyzed by One-way ANOVA and Tukey's Post-hoc test (p<0.05). Fluorine and calcium distributions of each specimen were evaluated using micro-PIGE/PIXE system at TIARA (Takasaki Ion Accelerators for Advanced Radiation Application, Takasaki JAPAN). The average fluorine concentration in each specimen was calculated at area of 70 µm from the defined surface. Data were analyzed by Games-Howell test (p<0.05).
Results:
| Control
| CTX
| F3
| MI
|
IML (Vol%* µm)
| 2520(755)A
| 1535(415)B
| 727(606)B,C
| 327(311)C
|
F uptake (ppm)
| 385 (150)A
| 1842(1766)A
| 1541(514)B
| 3760(3000)A
|
Mean(SD), Values indicating superscript are significantly different (p<0.05)
The IML of Control showed a significantly lower value than other three groups. For F uptake, F3 showed a significantly higher value than other three groups.
Conclusion:
After removing fluoride varnishes from the dentin surface, these surfaces still showed the demineralization preventing effect. Fluoride varnishes will work on the root carious preventing if it removed from the dentin surface.