Structural characteristics of staircase‐type retzius lines in human dental enamel analyzed by scanning electron microscopy

Risnes, Steinar

doi:10.1002/ar.1092260203

Cited by 41 publications

(29 citation statements)

References 35 publications

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“…In acid-etched sound human enamel, Risnes (1990Risnes ( , 1998 observed discontinuities in enamel prisms and interprismatic enamel as well as periodic prism constrictions along staircase-type lines of Retzius. The prism constrictions were regarded as indicative of a physiologic periodic reduction in diameter of the prism growth region of the Tomes' process, caused by a diminished rate of matrix secretion.…”

Section: Discussionmentioning

confidence: 97%

Fluoride-induced alterations of enamel structure: an experimental study in the miniature pig

Kierdorf

Richards

et al. 2004

Anatomy and Embryology

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We studied the structural changes in the enamel of mandibular third molars of miniature pigs administered a daily oral dose of 2 mg NaF (approximately 0.9 mg of fluoride) per kg body weight (added to the feed) for 1 year. The treatment period covered most of the secretory stage and the entire post-secretory stage of amelogenesis of the M(3). The enamel of the molars from the fluoride-fed pigs appeared opaque and chalky, and the erupted portions were stained brown. The underlying histopathological change was a pronounced subsurface hypomineralization of the enamel beneath a thin surface rim of higher mineral content. This enamel hypomineralization was attributed to a fluoride-induced impairment of the process of enamel maturation. The most conspicuous finding in the fluorotic enamel was the presence of numerous pit-type hypoplastic defects, denoting a marked fluoride-induced disturbance also of the secretory stage of amelogenesis. Microradiography and scanning electron microscopy revealed an enhanced incremental pattern in the outer enamel of the fluorotic molars. Typically, the bottom of larger hypoplastic defects was underlain by a broad, grossly accentuated incremental line. Occurrence of larger hypoplasias was further associated with the presence of aprismatic enamel, the formation of which was attributed to a loss of the prism-forming (distal) portion of the Tomes' processes of secretory ameloblasts. The findings in the miniature pigs closely parallel earlier observations on fluorotic enamel of free-ranging deer and wild boar from fluoride-polluted areas.

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Section: Discussionmentioning

confidence: 97%

Fluoride-induced alterations of enamel structure: an experimental study in the miniature pig

Kierdorf

Richards

et al. 2004

Anatomy and Embryology

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“…Retzius lines (Retzius, 1837), or long period markings, represent the successive location of the forming enamel front (Dean, 1987b;Risnes, 1990). Retzius line periodicity in permanent teeth is positively correlated with body mass in several extant and fossil primate taxa, as well as a sample of Proboscidea (Smith, 2008;Bromage et al, 2009), though some recently extinct lemurs are an exception (Schwartz et al, 2002).…”

Section: Background Incremental Enamel Markingsmentioning

confidence: 99%

Incremental enamel development in modern human deciduous anterior teeth

Mahoney

2012

American J Phys Anthropol

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This study reconstructs incremental enamel development for a sample of modern human deciduous mandibular (n = 42) and maxillary (n = 42) anterior (incisors and canines) teeth. Results are compared between anterior teeth, and with previous research for deciduous molars (Mahoney: Am J Phys Anthropol 144 (2011) 204-214) to identify developmental differences along the tooth row. Two hypotheses are tested: Retzius line periodicity will remain constant in teeth from the same jaw and range from 6 to 12 days among individuals, as in human permanent teeth; daily enamel secretion rates (DSRs) will not vary between deciduous teeth, as in some human permanent tooth types. A further aim is to search for links between deciduous incremental enamel development and the previously reported eruptionsequence. Retzius line periodicity in anterior teeth ranged between 5 and 6 days, but did not differ between an incisor and molar of one individual. Intradian line periodicity was 12 h. Mean cuspal DSRs varied slightly between equivalent regions along the tooth row. Mandibular incisors initiated enamel formation first, had the fastest mean DSRs, the greatest prenatal formation time, and based upon prior studies are the first deciduous tooth to erupt. Relatively rapid development in mandibular incisors in advance of early eruption may explain some of the variation in DSRs along the tooth row that cannot be explained by birth. Links between DSRs, enamel initiation times, and the deciduous eruption sequence are proposed. Anterior crown formation times presented here can contribute toward human infant age-at-death estimates. Regression equations for reconstructing formation time in worn incisors are given.

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“…Bundles of crystallites are packed in rods or interrod enamel. Rods contribute to the three-dimensional organization of enamel, either as linear structures, or forming sophisticated spatial constructions characterized as Hunter-Schreger (HS) bands (Osborn, 1990; Risnes, 1990). …”

Section: Introductionmentioning

confidence: 99%

Comparative studies between mice molars and incisors are required to draw an overview of enamel structural complexity

et al. 2014

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In the field of dentistry, the murine incisor has long been considered as an outstanding model to study amelogenesis. However, it clearly appears that enamel from wild type mouse incisors and molars presents several structural differences. In incisor, exclusively radial enamel is observed. In molars, enamel displays a high level of complexity since the inner part is lamellar whereas the outer enamel shows radial and tangential structures. Recently, the serotonin 2B receptor (5-HT2BR) was shown to be involved in ameloblast function and enamel mineralization. The incisors from 5HT2BR knockout (KO) mice exhibit mineralization defects mostly in the outer maturation zone and porous matrix network in the inner zone. In the molars, the mutation affects both secretory and maturation stages of amelogenesis since pronounced alterations concern overall enamel structures. Molars from 5HT2BR KO mice display reduction in enamel thickness, alterations of inner enamel architecture including defects in Hunter-Schreger Bands arrangements, and altered maturation of the outer radial enamel. Differences of enamel structure were also observed between incisor and molar from other KO mice depleted for genes encoding enamel extracellular matrix proteins. Thus, upon mutation, enamel analysis based exclusively on incisor defects would be biased. In view of the functional relationship between enamel structure and tooth morphogenesis, identification of molecular actors involved in amelogenesis requires comparative studies between mice molars and incisors.

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Structural characteristics of staircase‐type retzius lines in human dental enamel analyzed by scanning electron microscopy

Cited by 41 publications

References 35 publications

Fluoride-induced alterations of enamel structure: an experimental study in the miniature pig

Fluoride-induced alterations of enamel structure: an experimental study in the miniature pig

Incremental enamel development in modern human deciduous anterior teeth

Comparative studies between mice molars and incisors are required to draw an overview of enamel structural complexity

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