IADR Abstract Archives
Structural and Mechanical Characterization of Enamel Remineralized With Peptide shADP5
Objectives: Structural and mechanical characterization of a newly formed mineral layer on artificially demineralized human enamel using amelogenin-derived biomineralizing 18-AA long peptide shADP5 were carried out towards developing viable protocols for dental treatment.
Methods: Six groups were prepared to carry out remineralization on human enamel lesions with 50mM acetic acid up to 200µm deep: No treatment (control, Group 1), Ca2+ and PO43- only (Group 2), 1100ppm fluoride (Group 3), 20,000ppm fluoride (Group 4), 1100ppm fluoride and shADP5-peptide (Group 5), and shADP5-peptide alone (Group 6). Upon remineralization tests , structural and mineral phase characterization were undertaken by SEM and TEM imaging and diffraction analyses. The hardness and elastic moduli were determined by nanoindentation testing using Berkovich indenter. 20 measurements per group were recorded. Measurements were pooled from 5 specimens per group. The average values and standard deviations were calculated as mean ± standard error.
Results: While no treatment samples (Group1) showed plate-like crystals of hydroxyapatite (HAp), the sample prepared with Ca2+ and PO43- ions (Group2) displayed either small particles or structures that possibly correspond to the underlying enamel. 1100ppm (Group3) and 20,000ppm fluoride (Group4) samples displayed clusters of nanoscale and larger particles, respectively. 1100ppm fluoride and peptide containing samples (Group5) exhibited elongated particles of HAp with random crystallographic organization. shADP5-peptide alone samples (Group6) displayed HAp crystallites with aligned organization, reminiscent of the HAp plate-like particles. Indentation characterization of the mineral layer was possible in cross-section only for the shADP5-peptide alone samples where mineral layers thick enough. For all other treatment groups, nanoindentation characterization of the layers were partially accomplished because of the thin or discontinuous nature of the layers.
Conclusions: Among the test groups, only the shADP5-peptide alone samples resulted in remineralization of fairly thick (10 µm) dense mineralized layer which was structurally integrated with the underlying enamel.
Methods: Six groups were prepared to carry out remineralization on human enamel lesions with 50mM acetic acid up to 200µm deep: No treatment (control, Group 1), Ca2+ and PO43- only (Group 2), 1100ppm fluoride (Group 3), 20,000ppm fluoride (Group 4), 1100ppm fluoride and shADP5-peptide (Group 5), and shADP5-peptide alone (Group 6). Upon remineralization tests , structural and mineral phase characterization were undertaken by SEM and TEM imaging and diffraction analyses. The hardness and elastic moduli were determined by nanoindentation testing using Berkovich indenter. 20 measurements per group were recorded. Measurements were pooled from 5 specimens per group. The average values and standard deviations were calculated as mean ± standard error.
Results: While no treatment samples (Group1) showed plate-like crystals of hydroxyapatite (HAp), the sample prepared with Ca2+ and PO43- ions (Group2) displayed either small particles or structures that possibly correspond to the underlying enamel. 1100ppm (Group3) and 20,000ppm fluoride (Group4) samples displayed clusters of nanoscale and larger particles, respectively. 1100ppm fluoride and peptide containing samples (Group5) exhibited elongated particles of HAp with random crystallographic organization. shADP5-peptide alone samples (Group6) displayed HAp crystallites with aligned organization, reminiscent of the HAp plate-like particles. Indentation characterization of the mineral layer was possible in cross-section only for the shADP5-peptide alone samples where mineral layers thick enough. For all other treatment groups, nanoindentation characterization of the layers were partially accomplished because of the thin or discontinuous nature of the layers.
Conclusions: Among the test groups, only the shADP5-peptide alone samples resulted in remineralization of fairly thick (10 µm) dense mineralized layer which was structurally integrated with the underlying enamel.