Microhardness and microstructure of deciduous enamel with different types of amelogenesis imperfecta

Abstract

<jats:title>Abstract</jats:title><jats:p>Amelogenesis imperfecta (AI) is an inherited tooth disorder with widely varying phenotypes. The aim of this study was to determine the microhardness and microstructure characteristics of the enamel in AI teeth. The AI phenotypes examined were hypoplastic (pitted and smooth form), hypomaturated, and hypocalcified. Six AI patients were diagnosed according to clinical characteristics. The microhardness of the enamel was measured on axial cuts of AI teeth acquired from the patients. The measurements were done on several sites from the enamel surface towards the dentine-enamel junction using the Vickers scale. Values of microhardness were compared to corresponding control teeth. The microstructure of AI enamel types was evaluated using scanning electron microscopy. The values of microhardness in pitted hypoplastic AI samples were, on average, lower compared to the control enamel and dropped markedly towards the dentine-enamel junction. The smooth hypoplastic enamel was not only extremely thin but also much softer than control enamel. The values for hypomaturated AI fluctuated, but the palatal sites were markedly softer than in the control tooth. Hypocalcified enamel was the softest, with values resembling those of dentin. Microstructural changes varied from altered orientation of enamel prisms in pitted hypoplastic AI to lack of normal prismatic structure and severe porosity in hypocalcified AI. The present results suggest different microhardness profiles and microstructures in each phenotype. Variations among phenotypes are expected with larger case selection in this genetically heterogeneous disease.</jats:p>

Compositional, structural and mechanical comparisons of normal enamel and hypomaturation enamel

“…However, owing to the scarcity of available enamel samples and/or the lack of appropriate technologies, hypomaturation enamel is still poorly investigated. To the best of our knowledge, a limited number of studies have simply observed the structure of hypomaturation enamel and evaluated its elemental and protein content [22,23]. Detailed is still deficient and no previous study has systematically evaluated the structural organization of hypomaturation enamel at different hierarchical levels.…”

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

“…The mechanical properties (Vickers microhardness test) of deciduous hypoplastic enamel (pitted and smooth form) caused by AI (Amelogenesis Imperfecta) have been investigated by Pavlič et al [14]. They found that the values of microhardness in pitted hypoplastic AI samples were, on average, lower as compared to the control enamel and dropped markedly towards the dentine-enamel junction.…”

“…They found that the values of microhardness in pitted hypoplastic AI samples were, on average, lower as compared to the control enamel and dropped markedly towards the dentine-enamel junction. The smooth hypoplastic enamel was not only extremely thin but also much softer than control (intact) enamel [14]. The microstructure of AI enamel was evaluated using scanning electron microscopy (SEM).…”

Enamelin Directs Crystallite Organization at the Enamel-Dentine Junction

“…A major clinical concern is the underdiagnoses of ENAM-mutated hypoplastic enamel, as the surface can appear to be normal, yet severe microstructural defects appear beneath the subsurface layer, observed microscopically by the irregular arrangement of crystals within the prisms, undefined boundaries, and fusion of crystals, giving an amorphous-like appearance (Shore et al 2010). Hypoplastic enamel displays soft and thin enamel with an overall lower microhardness in comparison with healthy enamel (Pavlic et al 2007).…”