J Korean Acad Conserv Dent.  2008 Nov;33(6):507-517. 10.5395/JKACD.2008.33.6.507.

The effect of lactic acid concentration and ph of lactic acid buffer solutions on enamel remineralization

• Kwon JW
• Suh DG
• Song YJ
• Lee Y
• Lee CY

• KMID: 1428461
• DOI: http://doi.org/10.5395/JKACD.2008.33.6.507

Abstract

There are considerable in vitro and in vivo evidences for remineralization and demineralization occurring simultaneously in incipient enamel caries. In order to "heal"the incipient dental caries, many experiments have been carried out to determine the optimal conditions for remineralization. It was shown that remineralization is affected by different pH, lactic acid concentrations, chemical composition of the enamel, fluoride concentrations, etc. Eighty specimens from sound permanent teeth without demineralization or cracks, 0.15 mm in thickness, were immersed in lactic acid buffered demineralization solutions for 3 days. Dental caries with a surface zone and subsurface lesion were artificially produced. Groups of 10 specimens were immersed for 10 or 12 days in lactic acid buffered remineralization solutions consisting of pH 4.3 or pH 6.0, and 100, 50, 25, or 10 mM lactic acid. After demineralization and remineralization, images were taken by polarizing microscopy (x100) and micro-computed tomography. The results were obtained by observing images of the specimens and the density of the caries lesions was determined. 1. As the lactic acid concentration of the remineralization solutions with pH 4.3 was higher, the surface zone of the carious enamel increased and an isotropic zone of the subsurface lesion was found. However, the total decalcification depth increased at the same time. 2. In the remineralization solutions with pH 6.0, only the surface zone increased slightly but there was no significant change in the total decalcification depth and subsurface zone. In the lactic acid buffer solutions with the lower pH and higher lactic acid concentration, there were dynamic changes at the deep area of the dental carious lesion.

Keyword

Dental caries; Demineralization; Remineralization; Lactic acid; pH; Polarizing microscopy; Micro-computed tomography

MeSH Terms

Dental Caries
Dental Enamel
Fluorides
Hydrogen-Ion Concentration
Lactic Acid
Microscopy
Tooth
Fluorides
Lactic Acid

Figure

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  Figure 1 Polarizing microscopic observation of demineralized enamel. (Group 1, ×100) The white circle indicates surface zone.

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  Figure 2 Polarizing microscopic observation of remineralized enamel with 100 mM lactic acid buffer. (pH 4.3 :Group 1)The white arrow indicates isotropic zone.

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  Figure 3 Polarizing microscopic observation of demineralized enamel. (Group 2, ×100)

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  Figure 4 Polarizing microscopic observation of remineralized enamel with 50 mM lactic acid buffer. (pH 4.3 : Group 2)

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  Figure 5 Polarizing microscopic observation of demineralized enamel. (Group 3, ×100)

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  Figure 6 Polarizing microscopic observation of remineralized enamel with 25 mM lactic acid buffer. (pH 4.3 : Group 3)

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  Figure 7 Polarizing microscopic observation of demineralized enamel. (Group 4, ×100)

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  Figure 8 Polarizing microscopic observation of remineralized enamel with 10 mM lactic acid buffer. (pH 4.3 : Group 4)

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  Figure 9 Polarizing microscopic observation of demineralized enamel. (Group 5, ×100)

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  Figure 10 Polarizing microscopic observation of remineralized enamel with 100 mM lactic acid butter. (pH 6.0:Group 5)

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  Figure 11 Polarizing microscopic observation of demineralized enamel. (Group 6, ×100)

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  Figure 12 Polarizing microscopic observation of remineralized enamel with 50 mM lactic acid buffer. (pH 6.0 : Group 6)

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  Figure 13 Polarizing microscopic observation of demineralized enamel. (Group 7, ×100)

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  Figure 14 Polarizing microscopic observation of remineralized enamel with 25 mM lactic acid buffer. (pH 6.0 : Group 7)

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  Figure 15 Polarizing microscopic observation of demineralized enamel. (Group 8, ×100)

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  Figure 16 Polarizing microscopic observation of remineralized enamel with 10 mM lactic acid buffer. (pH 6.0 : Group 8)

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  Figure 17 Demineralized depth at pH 4.3 solutions. (demineralized depth after remineralization/demineralized depth after demineralization) × 100 (%)

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  Figure 18 Demineralized depth at pH 6.0 solutions. (demineralized depth after remineralization/demineralized depth after demineralization) × 100 (%)

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  Figure 19 Surface lesion depth of dental carious in enamel at pH 4.3 solutions.(depth of surface lesion after remineralization/depth of surface lesion after demineralization) × 100 (%)

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  Figure 20 Surface lesion depth of dental carious in enamel at pH 6.0 solutions.-(depth of surface lesion after remineralization/depth of surface lesion after demineralization) × 100 (%)

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  Figure 21 Comparison of density in enamel before and after remineralization with 100 mM lactic acid buffer by micro-CT. (pH 4.3 : Group 1)

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  Figure 22 Comparison of density in enamel before and after remineralization with 50 mM lactic acid buffer by micro-CT. (pH 4.3 : Group 2)

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  Figure 23 Comparison of density in enamel before and after remineralization with 25 mM lactic acid buffer by micro-CT. (pH 4.3 : Group 3)

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  Figure 24 Comparison of density in enamel before and after remineralization with 10 mM lactic acid buffer by micro-CT. (pH 4.3 : Group 4)

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  Figure 25 Comparison of density in enamel before and after remineralization with 100 mM lactic acid buffer by micro-CT. (pH 6.0 : Group 5)

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  Figure 26 Comparison of density in enamel before and after remineralization with 50 mM lactic acid buffer by micro-CT. (pH 6.0 : Group 6)

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  Figure 27 Comparison of density in enamel before and after remineralization with 25 mM lactic acid buffer by micro-CT. (pH 6.0 : Group 7)

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  Figure 28 Comparison of density in enamel before and after remineralization with 10 mM lactic acid buffer by micro-CT. (pH 6.0 : Group 8)

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