The influence of hardness and chemical composition on enamel demineralization and subsequent remineralization

Rana Alkattan, Frank Lippert, Qing Tang, George J. Eckert, Masatoshi Ando

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Objectives: The objectives were to investigate the hardness and chemical composition of sound, demineralized and pH-cycled bovine enamel and determine their influence on demineralization and remineralization behavior. Methods: Ninety-four, 5 × 5 × 2-mm bovine enamel specimens were demineralized using three different times [(24 h (n = 33), 48 h (n = 30), 96 h (n = 31)]. The specimens were then pH-cycled using either 367 ppm F sodium fluoride or deionized water. Knoop hardness (HK) and energy-dispersive X-ray spectroscopy (measured elements: Ca, P, F, C, Mg, N) were performed at three stages (sound, after demineralization, after pH-cycling) and transverse microradiography was performed after demineralization and pH-cycling. Comparisons were determined by ANOVA. Results: Results showed that HK, integrated mineral loss and lesion depth were significantly different between stages, demineralization times and treatments. The weight% of F at the surface was significantly affected by treatment, irrespective of demineralization time, while the Ca:P ratio of the enamel remained stable even after de- and remineralization protocols. The F in fluoride groups and the artificial saliva in non-fluoride groups were both able to induce enamel remineralization, indicating the protective effect of salivary pellicle against demineralization even in the absence of fluoride. Conclusions: Harder specimens and those with greater surface F weight% were less susceptible to demineralization and were more likely to remineralize. However, the amount of surface Ca and P did not influence de- or remineralization behavior. Clinical Significance: This in vitro study can help clinicians better understand the caries process and the impact of the physical and chemical characteristics of enamel on its behavior during de- and remineralization. The over-the-counter fluoride toothpaste containing 1100 ppm-F was used, and was able to produce a mineralized enamel surface layer.

Original languageEnglish (US)
Pages (from-to)34-40
Number of pages7
JournalJournal of Dentistry
StatePublished - Aug 2018


  • Bovine
  • Chemical
  • Composition
  • Enamel
  • Hardness
  • Mineral

ASJC Scopus subject areas

  • Dentistry(all)

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