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Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Retzius, Magnus Gustav (1842–1919) Neuroanatomist at the Karolina Institute in Stockholm. He described the brown lines in the enamel of teeth, known as striae of Retzius, in 1890 and several structures of the brain which are named after him.
Paleopathology and paleomedicine
Published in Lois N. Magner, Oliver J. Kim, A History of Medicine, 2017
Bone fractures provide a record of trauma, which might be followed by infection or by healing. The developing bones of children are particularly vulnerable to trauma, infections, and growth disorders. Stresses severe enough to disrupt growth during childhood result in transverse lines, usually called Harris lines or growth arrest lines that are visible in radiographs of the long bones of the body. Because Harris lines suggest severe, but temporary disturbance of growth, a population suffering from chronic malnutrition has fewer transverse lines than one exposed to periodic or seasonal starvation. Starvation, severe malnutrition, and acute infections may also leave characteristic signs in the teeth. These microdefects of dental enamel are known as pathological striae of Retzius, enamel hypoplasias, or Wilson bands. Severe episodes of infantile diarrheas, for example, can disrupt the development of teeth and bones. Scanning electron microscopy makes it possible to observe disruptions in the pattern of these lines, but there is still considerable uncertainty about the meaning of these formations.
Dental Fluorosis
Published in Colin Robinson, Jennifer Kirkham, Roger Shore, Dental Enamel, 2017
Pamela K. DenBesten, Nina J. Giambro
The ultrastructure of fluorosed enamel shows organic matter between a mixture of large and small, sparsely arranged crystallites.18,25-27 Bands of relatively well- and poorly calcified enamel run parallel to the striae of Retzius. The outer region of fluorosed enamel contains highly uniform, flattened, hexagonal crystals, while the inner region of enamel contains irregular crystals more closely resembling those described in normal adult enamel.15,27 More recently, high resolution electron microscopy has been used to evaluate the surface layer of human fluorosed enamel and has identified the small crystals in the highly mineralized surface layer as fluorapatite.28 It should be noted that similar findings have been reported in carious enamel lesions where newly formed small crystals have been observed in the highly mineralized surface layer.29,30
Comparison of remineralization by fluoride varnishes with and without casein phosphopeptide amorphous calcium phosphate in primary teeth
Published in Acta Odontologica Scandinavica, 2019
Nehal Raid Salman, Magda ElTekeya, Niveen Bakry, Samia Soliman Omar, Maha El Tantawi
Using polarized light microscopy [24], longitudinal ground enamel sections of 15 µm thickness were examined to measure lesion depth. Polarized light microscope can show different birefringence. The minerals in enamel refract polarized light in rays with 2 different amplitudes and refractive indices related to two planes of transmission (birefringence). The positive birefringence refers to the ray with the smaller amplitude (the slower ray) and the negative birefringence refers to the ray with the bigger amplitude (the faster ray). Respectively, these can be seen as dark, brown color and bluish green color [24]. Normal enamel was identified through its prismless surface layer, a dark continuous ribbon over the surface with striae of Retzius and alternative Hunter-Shreger bands (Figure 1). Demineralized enamel showed different zones (deep to superficial); a translucent zone, a dark zone, body of lesion and surface zone with positive birefringence (dark color) and loss of striae of Retzius and Hunter-Shreger bands (Figure 2). Remineralized enamel showed negative birefringence (greenish blue color) in MI varnish group (Figure 3) and in Prevident varnish group (Figure 4). Photomicrographs were obtained using a digital camera to measure lesion depth through an eyepiece-graduated lens micrometer with magnification = ×40. The mean depth in micrometers (µm) was the average of three lines: one on each side of the lesion and a third one in the center [25]. Examiner consistency was checked by repeated measurement of 10 specimens and comparing the duplicates using paired t test where no significant difference was found between these values.
Enamel multidien biological timing and body size variability among individuals of Chinese Han and Tibetan origins
Published in Annals of Human Biology, 2021
Hakan Karaaslan, Jeffrey Seckinger, Amel Almabrok, Bin Hu, Hui Dong, Dengsheng Xia, Tsering Dekyi, Russell T. Hogg, Jian Zhou, Timothy G. Bromage
Beyond the daily formation rhythm in enamel is a longer period incremental line, the striae of Retzius (Boyde 1964; Bromage et al. 2012), whose so-called RP is represented by the number of cross striations between two consecutive striae (Figures 1–3). The RP in permanent tooth enamel is variable between species and individuals of species, yet it is consistent within an individual (FitzGerald 1998). Moreover, RP is shown to be positively correlated with body mass interspecifically among living and fossil primates and other species (Smith et al. 2003; Smith 2006; Bromage and Janal 2014; Smith 2016), yet suggested to be negatively correlated intraspecifically (Bromage, Juwayeyi, et al. 2016).