Morphological study of hard dental tissue condition with various types of dental deposits

Today, it has been established that the primary factor in preventing dental caries is controlling the level and type of dental deposits. However, the literature has not yet addressed the specific morphological changes in the hard dental tissues when non-mineralized and mineralized dental plaque is present on the tooth surface. The aim of this study was to examine the microscopic structure of the cuticle and hard dental tissues and to assess the X-ray spectral changes associated with different types of dental deposits. Epimicroscopic and X-ray spectral examinations were performed on 32 teeth with various types of supragingival deposits, extracted for orthodontic and surgical indications. Each tooth was cut in the vestibulo-oral direction using a diamond bur at low speed, then one half was polished, stained with PAS-Alcian blue, and photographed at different magnifications in epiprojection. Samples were carbon-coated in a vacuum chamber, and the inorganic components in the cuticle and mineralized deposits were assessed using the Link AN 10.85s micro X-ray analyzer. Thin sections of the other tooth halves were prepared, stained with PAS-Alcian blue, and examined under the “Olympus” microscope at various magnifications. Statistical analysis was performed using standard parametric methods with “Statistica 6.0” and “Microsoft Excel 2002” software. Significant findings in the hard dental tissues included the presence of non-mineralized (soft plaque, dental biofilm), mineralized (dental calculus), and smoker's plaque. In areas with soft plaque, enamel prisms remained intact, with no changes in the enamel-dentin junction or dentin, though the cuticle was nearly absent. In areas with dental biofilm, enamel thickening, the absence of characteristic enamel prism patterns, fragmentation of the reticular layer, and formation of interglobular dentin were observed. Morphological changes in mineralized deposits included enamel thinning, prism disorganization, localized hypermineralization, destroyed enamel-dentin junctions, and “dead tracts” in the dentin. In cases with smoker's plaque, nicotine pigment accumulated in Retzius line biomineralization zones, along with thickening of the reticular layer and “dead tracts” in the deeper dentin layers. A comparison of the main inorganic components (Ca, P, Mg, Ca/P) in the cuticle and mineralized deposits showed significant differences in phosphate, magnesium, and Ca/P ratios, indicating disrupted metabolic processes at the “enamel-oral fluid” interface, promoting calculus formation. Thus, the morphological and X-ray spectral changes observed in the enamel and surrounding tissues provide an objective assessment of tissue condition with various types of deposits. These findings should be considered in selecting a scaling method.