A Quantitative Microradiographic Study of Incipient Enamel Caries

Abstract

SYNOPSIS IN INTERLINGUAUN QUANTITATIVE STUDIO MICRORADIOGRAPHIC DE INCIPIENTE CARIE ADAMANTIN.-Le strato superficial del cariose adamante studiate habeva perdite approximativemente 8 pro cento de su sales mineral. Le valor medie del spissitate del strato superficial esseva 40 gA, e le valor medie de su contento mineral esseva 82,7 pro cento a base del volumine. Le dismineralisation subsuperficial monstrava marcate variationes. Le contento mineral le plus basse esseva 28,9 pro cento a base del volumine, e iste alte grado de dismineralisation esseva trovate in un lesion de un profundor de 300 A sin ruptura del superficie.Quantitative microradiography has been used only to a limited extent for studying dental hard tissues. Thewlis' and Angmar, Carlstrdm, and Glas' have used the technique for studying normal human enamel, but to our knowledge no quantitative microradiographic investigation of carious enamel has been published. Semiquantitative data have been published, and the results have then usually been presented graphically with densitometric tracings, giving a view of the degree of decalcification.3"6 The semiquantitative technique is a valuable tool for detecting variations in the degree of mineralization in a hard tissue, but it can only give relative data. Insufficient literature and the need for more detailed information about the degree of decalcification in dental caries can be regarded as the background of the present investigation. It is believed that the quantitative microradiographic technique can be of value for throwing light on the pathogenesis of dental caries. Materials and MethodsThe material consisted of eleven premolars from individuals 10-15 years of age. The teeth, which were extracted on orthodontic indications, exhibited early approximal enamel caries and were otherwise intact, without signs of developmental disturbances. In nine cases the lesion consisted only of a white, opaque spot without cavitation; in the remaining two cases there existed a shallow cavitv in the center of the white spot. After fixation in absolute alcohol the teeth were serially sectioned longitudinally with a diamond wheel without prior embedding. The cutting direction was perpendicular to the carious surface, and the interval between two adjoining sections in each series was 300 ,. The number of sections of each lesion depended on its width and varied between five and fourteen. The sections were ground planoparallel and polished, the final thickness being 70-80 y. From each serialsectioned tooth the section with the deepest part of the lesion was chosen for microradiographic examination.The thickness of the ground sections was measured in the following way. Each section was divided with a diamond wheel parallel to the direction of the enamel prisms through the deepest part of the carious lesion and perpendicular to the ground surfaces of the section. The section was then viewed in a microscope with a X50 lens and with the cut surface of the section at right angles to the optical axis. The thickness measurement was ...

Synchrotron X-Ray Microtomographic Investigation of Mineral Concentrations at Micrometre Scale in Sound and Carious Enamel

“…10-30 Ìm from SEM measurement [Haikel et al, 1983] and 40 Ìm from microradiography [Bergman and Lind, 1966]. The slightly greater thickness observed in our study of lesions in older teeth might reflect a longer history of demineralization.…”

Protection of sound enamel and artificial enamel lesions against demineralisation: Caries infiltrant versus adhesive

“…2 However, although these lesions were shown to exhibit some of the typical histological structure of intact enamel caries including the intact surface layer, 8 the histological condition of the surface und subsurface layers is unpredictable in the clinical situation. The surface layer is thicker in natural (~ 40 to 50 µm and) compared to artificial (~ 20 µm) lesions, 3 but it was shown that hydrochloric acid etching is required not only for natural 23 but also for artificial caries lesions 2 to remove the surface layer completely and allow for successful penetration of the infiltrant. It was therefore decided to use the infiltration material as provided in the commercially available kit, i.e.…”

High-resolution X-ray microdiffraction analysis of natural teeth

“…The texture effect of the natural tooth was discovered many years ago; it was also called 'two fiber axes', and was thought to exist in the Hunter-Scherger bands in the enamel (Bergman & Lind, 1966;Hirota, 1982Hirota, , 1986. In our experiment we observed an obvious texture effect in the enamel with the Debye ring patterns; further calculation of the texture index revealed that the crystal preferred orientation was mainly evident in the reflection (002), which is similar to the findings of Hirota (1986) who considered that the phenomenon was caused by the reflections of two zones of the Hunter-Schreger bands being recorded simultaneously on X-ray film.…”

“…It is also very difficult to analyse a small zone affected by caries because the amount of powder obtained from the small zone will be insufficient for the diffraction method; also, the in situ crystal orientation is demolished after grinding. During the last century, microzone X-ray diffraction was carried out by some researchers, but, as the equipment was less sophisticated at that time, it was difficult to focus the X-ray beam on a small target area in a natural tooth with initial caries, the signal detected was very weak, and, as a result, the data obtained were not good enough for thorough analysis (Bergman & Lind, 1966). The recent developments of a new kind of high-resolution detector and the monocapillary confocal lens have greatly improved the sensitivity of X-ray diffraction, and made it possible to analyse in situ the microzone of tooth mineral crystallite (Busson et al, 1999;Friedel et al, 2005;Nakano et al, 2002).…”