Characterization of the nanoscratch, microstructure, and composition in hypoplastic amelogenesis imperfecta

Abstract

Hypoplastic amelogenesis imperfecta is a widespread hereditary disease that causes the loss of enamel. The purpose of this study was to investigate the nanoscratch resistance of hypoplastic amelogenesis imperfecta for providing a reference for restorative treatment. Four unerupted third molars from a patient diagnosed with hypoplastic amelogenesis imperfecta and seven unerupted third molars from normal individuals were compared. Atomic force microscopy and energydispersive X-ray spectroscopy were used to observe the microstructure and composition of the teeth (enamel and dentin). The nanoscratch tests of teeth (enamel and dentin) were investigated using a nanoscratch tester, scanning electron microscopy, and a stylus profilometer. The results indicated that hypoplastic amelogenesis imperfecta teeth had different microstructures compared to normal teeth. Hypoplastic amelogenesis imperfecta demonstrated a higher composition of organic substance. Meanwhile, the friction coefficient of hypoplastic amelogenesis imperfecta was higher than that of normal teeth, and inferior frictional resistance of hypoplastic amelogenesis imperfecta teeth was observed. The main damaging mechanisms observed in hypoplastic amelogenesis imperfecta under nanoscratch were the combination of delamination, debris, and cracks in enamel with delamination, debris, and plastic deformation in dentin. Our findings suggested that new dental restorative materials should be selected to match the mechanical properties of hypoplastic amelogenesis imperfecta.

Hyper‐spectral Raman imaging correlating chemical substitution and crystallinity in biogenic hydroxyapatite: Dentin and enamel in normal and hypoplastic human teeth

“…A largely constant FWHM in dentin and enamel of the hypoplastic tooth contrasts a divergence in the FWHM between the enamel versus dentin in normal teeth. Recent studies of amelogenesis imperfecta teeth [7,8,[25][26][27]30] identified low degree of crystallinity at selected locations and linked to higher carbonate content in the hypomineralized/hypoplastic enamel. However, in our hypoplastic case, the signature of an elevated protein content in hypoplastic enamel (see Figure S6) with only a minor difference in Ca/P, too small to account for the Raman spectral differences, would rather suggest the protein content as the origin of the reduced degree of mineralization and crystallinity.…”

“…However, in our hypoplastic case, the signature of an elevated protein content in hypoplastic enamel (see Figure S6) with only a minor difference in Ca/P, too small to account for the Raman spectral differences, would rather suggest the protein content as the origin of the reduced degree of mineralization and crystallinity. [7,25,27] It is worth noting that not all tooth disorders lead to a decreased linewidth. Low values of FWHM in a study of sclerotic dentin in noncarious cervical lesions [12,13] suggested a hyperminearlized dentin in that case.…”

“…Recent studies of amelogenesis imperfecta teeth identified low degree of crystallinity at selected locations and linked to higher carbonate content in the hypomineralized/hypoplastic enamel. However, in our hypoplastic case, the signature of an elevated protein content in hypoplastic enamel (see Figure S6) with only a minor difference in Ca/P, too small to account for the Raman spectral differences, would rather suggest the protein content as the origin of the reduced degree of mineralization and crystallinity . It is worth noting that not all tooth disorders lead to a decreased linewidth.…”

“…Hypoplastic type enamel is a form of amelogenesis imperfecta, which belongs to a surface defect of the tooth crown [24] and has become the focus of recent studies. [7,8,[25][26][27] The main feature of the hypoplastic teeth is a much thinner enamel than in normal tooth, with lower degree of mineralization with higher organic content, lower degree of crystallinity with more carbonate/Mg content and smaller crystal size, and lower microhardness.…”

Compositional and micromorphological features of hypoplastic enamel in children’s permanent teeth

“…The investigation of the nanoscratch resistance of hypoplastic amelogenesis imperfecta enamel and dentine [15] using atomic force microscopy (AFM), energy-dispersive X-ray (EDS) spectroscopy and a nanoscratch tester has indicated that hypoplastic teeth have different microstructures as compared to normal teeth; hypoplastic amelogenesis imperfecta demonstrated a higher amount of organic substance.…”