139 Fluoride Response of Human and Bovine Enamel under pH-Cycling Conditions

Thursday, March 22, 2012: 10:45 a.m. - 12:15 p.m.
Presentation Type: Oral Session
F. LIPPERT, A. HARA, and D. ZERO, Preventive and Community Dentistry, Indiana University School of Dentistry, Indianapolis, IN

Objective: To compare the fluoride response of HE and BE caries lesions in an established pH-cycling caries model.

Methods: Caries-like lesions were formed in HE and BE (lactic acid solution-LA). Test products were: 0/250/1100ppm F NaF/silica formulation 1, 1100ppm F NaF/silica formulation 2, 1100ppm F MFP/calcium carbonate. The daily cycling regimen comprised: 4x1min dentifrice slurry treatments; 1x4h LA challenge and remineralization in a 50:50-mixture of pooled human/artificial saliva. After 20days, Vickers surface microhardness (VHN) was measured (REM=change from baseline), EFU determined (microdrill), specimens were challenged with LA and VHN measured again (DEM). Data were analyzed using two-way ANOVA (alpha=0.05; factors: enamel, treatment).

Results: Both enamel type and treatment as well as their interaction affected REM and DEM. EFU was only affected by treatment. Table shows means (SEM).

enamel

Treatment

REM

DEM

EFU

human

0F-NaF1

0(2)

C

-8(2)

D

124(191)

D

250F-NaF1

11(2)

B

7(2)

C

1415(191)

C

1100F-NaF1

45(2)

A

35(2)

B

4078(191)

B

1100F-NaF2

50(3)

A

44(2)

A

4776(196)

A

1100F-MFP

7(2)

BC

4(2)

C

1344(196)

C

bovine

0F-NaF1

-2(2)

d

-6(2)

c

122(196)

c

250F-NaF1

13(3)

c

9(2)

b

1314(191)

b

1100F-NaF1

74(2)

b

58(2)

a

3826(196)

a

1100F-NaF2

81(2)

a

64(2)

a

4267(191)

a

1100F-MFP

10(2)

c

7(2)

b

1143(196)

b

Significant differences between treatments within enamel types are highlighted by letters, differences between enamel types within treatments in bold.

HE and BE showed a good F dose-response and correlated well. BE showed more remineralization than HE, but only at elevated [F]. There were good correlations between fluoride concentration (0/250/1100ppm F-NaF1;[F]) vs. REM, [F] vs. EFU and REM vs. EFU, regardless of enamel type.

Conclusions: Human and bovine enamel showed a similar fluoride response, but of different magnitudes with bovine enamel being more reactive to fluoride.

This study was in part supported by GlaxoSmithKline.

This abstract is based on research that was funded entirely or partially by an outside source: This study was in part supported by GlaxoSmithKline

Keywords: Caries, Demineralization, Enamel, Fluoride and Remineralization