A possible mechanism of acquired acid resistance of human dental enamel by laser irradiation

Caries Res. 1990;24(2):86-92. doi: 10.1159/000261245.


A possible mechanism of acquired acid resistance of lased enamel was proposed on the basis of the investigations of optical properties, compositional and structural changes and permeability of lased and unlased human dental enamel. Lased enamel showed a high positive birefringence, suggesting the formation of 'microspaces' in enamel. No new products were found, though a decrease of lattice strain and a slight a-axis contraction were recognized in lased enamel compared with unlased enamel. The contents of water, carbonate and organic substances were reduced in lased enamel. Gradual changes of birefringence were observed in lased enamel during treatment with acid solutions, and this change was attributed to mineralization of the microspaces. The ions released by an acid decalcification would be trapped in the microspaces in lased enamel, whereas such ions diffuse to the surrounding solution in unlased enamel.

MeSH terms

  • Acids / pharmacology
  • Acidulated Phosphate Fluoride / pharmacology
  • Calcium / pharmacology
  • Citrates / pharmacology
  • Dental Enamel / drug effects
  • Dental Enamel / radiation effects*
  • Dental Enamel Permeability / drug effects
  • Dental Enamel Permeability / radiation effects*
  • Dental Enamel Solubility / drug effects
  • Dental Enamel Solubility / radiation effects*
  • Durapatite
  • Hot Temperature
  • Humans
  • Hydroxyapatites / radiation effects
  • Lactates / pharmacology
  • Lasers*
  • Microscopy, Polarization
  • Perchlorates / pharmacology
  • Rosaniline Dyes / pharmacology
  • Sodium Hydroxide / pharmacology
  • Spectrophotometry, Infrared
  • Thermogravimetry
  • Tooth Permeability / radiation effects*
  • X-Ray Diffraction


  • Acids
  • Citrates
  • Hydroxyapatites
  • Lactates
  • Perchlorates
  • Rosaniline Dyes
  • Acidulated Phosphate Fluoride
  • carbol-fuchsin solution
  • Sodium Hydroxide
  • Durapatite
  • Calcium