Enamel, the outermost layer of teeth, is an acellular mineralized tissue that cannot regenerate; the mature tissue is composed of high aspect ratio apatite nanocrystals organized into rods and inter-rod regions. Amelogenin constitutes 90% of the protein matrix in developing enamel and plays a central role in guiding the hierarchical organization of apatite crystals observed in mature enamel. To...

Most of what we know about the timing of human enamel formation comes from radiographic studies on children of known age. Here, we present new longitudinal data derived from a histological analysis of tooth enamel. Two samples, one from southern Africa and one from northern Europe, contained all anterior and molar tooth types. Two further samples contained only one tooth type: canines from a me...

Serological differentiation indices (SDIs) based on serum titrations in agar-gel double diffusion tests were determined for all ten definitive tombusviruses known at presen t, namely artichoke mottled crinkle, carnation Italian ringspot, cymbidium ringspot, eggplant mottled crinkle, Moroccan pepper, pelargonium leaf curl, petunia asteroid mosaic, the BS3 and type strains of tomato bushy stunt, ...

A genetic abnormality in collagen and elastin cross-linking resembling experimental lathyrism has been identified in mice. The defect is an X-linked trait, attributed to the mottled locus which also influences coat color. The affected mice have aneurysms of the aorta and its branches, weak skin, and bone deformities in a spectrum of severity varying with the alleles at the mottled locus. A defe...

Enamel formation requires consecutive stages of development to achieve its characteristic extreme mineral hardness. Mineralization depends on the initial presence then removal of degraded enamel proteins from the matrix via endocytosis. The ameloblast membrane resides at the interface between matrix and cell. Enamel formation is controlled by ameloblasts that produce enamel in stages to build t...

OBJECTIVE Ethanol wet-bonding (EWB) technique has been stated to decrease degradation of resin-dentin bond. This study evaluated the effect of two EWB techniques on composite resin-to-enamel bond strength. MATERIALS AND METHODS Silicon carbide papers were used to produce flat enamel surfaces on the buccal faces of forty-five molars. OptiBond FL (OFL) adhesive was applied on enamel surfaces in...

OBJECTIVE Interproximal enamel reduction is a part of orthodontic treatment for gaining a modest amount of space in the treatment of crowding. Today interproximal enamel reduction has become a viable alternative to the extraction of permanent teeth, and helps to adjust the Bolton Index discrepancy. The aim of the study is to evaluate various interproximal enamel reduction techniques, its indica...

OBJECTIVES To determine if Sa roughness data from measuring one central location of unpolished and polished enamel were representative of the overall surfaces before and after erosion. METHODS Twenty human enamel sections (4x4 mm) were embedded in bis-acryl composite and randomised to either a native or polishing enamel preparation protocol. Enamel samples were subjected to an acid challenge ...