The effect of strontium and combinations of strontium and fluoride on the remineralization of artificial caries lesions in vitro.
OBJECTIVE
To determine the effect of relatively low strontium concentrations on enamel remineralization and investigate the dose-response effects of strontium and fluoride combinations on the remineralization of artificial caries lesions in vitro.


METHODS
Artificial caries lesions were created in 135 bovine enamel specimens. Lesion severity was analyzed using transverse microradiography (TMR) and quantitative light-induced fluorescence (QLF). The specimens were randomly assigned to nine treatment groups based on lesion volume after lesion creation, as measured by TMR. Treatment groups were based on a 3 x 3 factorial design (0/0.05/0.1 ppm fluoride and 0/10/15 ppm strontium). Lesions were remineralized at 37°C for 14 days in artificial saliva, which was supplemented or not with NaF and/or SrCl2 x 6H2O. Lesion remineralization was assessed using QLF and TMR. Data were analyzed using ANOVA.


RESULTS
For the TMR data, lesion remineralization in the 10 ppm strontium + 0.05 ppm fluoride group was significantly higher than in all other groups (P < .05) except the 0 ppm strontium + 0.05 ppm fluoride group (P = .06). The 10 ppm strontium + 0 ppm fluoride group exhibited significantly less remineralization than the 0 ppm strontium + 0 ppm fluoride group (P = .048). For the QLF data, intergroup differences were not the same as for the TMR analysis. The QLF measurement was only moderately correlated with TMR mineral loss (r = -0.37).


CONCLUSIONS
Strontium alone did not improve the remineralization of artificial caries lesions under the chosen in vitro conditions. However, a synergistic effect between the combination of fluoride and strontium was found at specific concentrations.
Department of Preventive and Community Dentistry, Indiana University School of Dentistry, Indianapolis, Indiana, USA.
Ghaeth H
GH
Yassen
Frank
F
Lippert
George
G
Eckert
Jennifer
J
Eder
Andrea Ferreira
AF
Zandoná
D000818:Animals; D002327:Cariostatic Agents / Q000627:therapeutic use*; D002417:Cattle; D003731:Dental Caries / Q000175:diagnosis / Q000188:drug therapy; D003732:Dental Caries Activity Tests; D003743:Dental Enamel / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005453:Fluorescence; D008027:Light; D008852:Microradiography; D011897:Random Allocation; D012969:Sodium Fluoride / Q000627:therapeutic use; D013324:Strontium / Q000627:therapeutic use*; D014089:Tooth Remineralization / Q000379:methods*
D002327:Cariostatic Agents; D012969:Sodium Fluoride; C025700:strontium chloride; D013324:Strontium