The ultrastructure of human tooth enamel from a patient diagnosed to have amelogenesis imperfecta (AI) was investigated using atomic force microscopy (AFM) and compared with normal human tooth enamel. AI is a hereditary defect of dental enamel in which the enamel is deficient in either quality or quantity. Tissue-specific proteins, especially amelogenins, have been postulated to play a central role in amelogenesis. The secondary structure of amelogenin has been assigned an important role in directing the architecture of hydroxyapatite (HA) enamel crystallites and an alteration of the secondary structure of amelogenin is expected to result in an altered architecture of the mineral phase in human enamel. Previous studies have shown that the human amelogenin gene encodes for a mutant protein in which a conserved Pro is mutated to a Thr residue (Pro-->Thr); such a mutation should be expected to cause a disoriented pattern of the mineral phase in enamel. AFM results presented for the AI tooth enamel clearly demonstrate that the apatite crystal morphology in AI tooth enamel is perturbed in the diseased state; this might result from a defective synthesis of the extracellular matrix proteins, e.g. amelogenin, by the ameloblasts.
The ultrastructure of the human tooth enamel from a patient diagnosed with hypoplasia (HYP) was investigated using atomic force microscopy (AFM) and compared with the surface of normal human tooth enamel. Hypoplasia is a hereditary defect of dental enamel in which the enamel is deficient in either quality or quantity. AFM results presented for the HYP tooth enamel clearly demonstrate that the apatite crystal morphology in hypoplasia tooth enamel is perturbed in the diseased state which could result from a defective synthesis of the extracellular matrix proteins, e.g., amelogenin, by the ameloblasts. HYP enamel consisting of loosely packed, very small grains does not present a tendency for association, as in the case of the normal healthy tooth. Indeed, the enamel surface affected by HYP is porous and is made of much smaller grains. In some samples, the HYP part of enamel surface appeared in the form of a point-defect, which we believe may be associated with the early stages of the HYP deformation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.