Neonatal lines in the enamel of primary teeth—A morphological and scanning electron microscopic investigation

Sabel, Nina; Johansson, Carina B.; Kühnisch, Jan; Robertson, Agneta; Steiniger, Frank; Norén, Jörgen G.; Klingberg, Gunilla; Nietzsche, Sándor

doi:10.1016/j.archoralbio.2008.05.003

Cited by 94 publications

(72 citation statements)

References 18 publications

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“…Birth is thought to produce an accentuated marking, which has been named the neonatal line (Rushton, 1933;Schour, 1936;Weber and Eisenmann, 1971;Sabel et al, 2008). This line, and subsequent accentuated markings (e.g., Beynon et al, 1991b), can be used with cross-striations and Retzius lines to calculate pre-, and postnatal enamel formation time, and also to determine the growth sequence between teeth (e.g., Beynon et al, 1991a;Macho et al, 1996;Reid, 1998a,b;Schwartz et al, 2005Schwartz et al, , 2007.…”

Section: Background Incremental Enamel Markingsmentioning

confidence: 97%

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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Section: Background Incremental Enamel Markingsmentioning

confidence: 97%

Incremental enamel development in modern human deciduous anterior teeth

Mahoney

2012

American J Phys Anthropol

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“…In all cases used in present work, its identification and outline assessment at 100x was unambiguous, as this scar clearly divides the smooth course of prenatal enamel matrix formation from the "normal" structure of postnatal enamel matrix (Antoine et al 2009;FitzGerald et al 2006;Kodaka et al 1996;Mishra et al 2009;Risnes 2001;Rossi et al 1999;Rushton 1939;Sabel et al 2008;Schour 1936;Schour and Massler 1937;Skinner 1992;Skinner and Dupras 1993; SzpringerNodzak 1984; Weber and Einsenmann 1971;Whittaker and Richards 1978). To measure the NL width, three images were originally taken at 400x in three different positions, preferably along the buccal (labial) aspect: 1) close to the EDJ; 2) in the middle of the dental crown; and 3) close to the apex.…”

Section: Neonatal Line Thicknessmentioning

confidence: 99%

Gestation Length, Mode of Delivery, and Neonatal Line-Thickness Variation

Zanolli

Bondioli

Manni³

et al. 2011

Human Biology

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ABTRACTThe transition from an intra-to extra-uterine environment leaves its mark in deciduous teeth (and first permanent molars) as an accentuated enamel incremental ring called the neonatal line (NL). This prominent microfeature separates the enamel formed during intrauterine life from that formed after leaving the womb. However, while the physical structure of this scar is well known, the bases of its formation are still a matter of investigation. In particular, besides the influence of the birth-related abrupt environmental and dietary changes and the role played by physiological factors such as hypocalcaemia, it has been suggested a direct relationship between NL thickness variation and the physical trauma implied by the birth dynamics, the Caesarean and the operative modes being apparently associated to the thinnest and the thickest lines, respectively. By using the histological record from a deciduous dental sample (exfoliated crowns) of 100 modern healthy school-aged children (47 males and 53 females) of reported birth histories (normal delivery mode: 55 cases; Caesarean: 40; operative: 5), we investigated the relationships between birth dynamics and NL thickness variation. The Tukey Honest Significant Difference method has been used to test the differences between the means of the grouping levels. The results of our histo-morphological investigation do not support the suggestion that Caesarean-born children display, on average, a thinner enamel scar compared to children associated to a normal delivery mode. Rather, our study points to the influence exerted by factors intimately related to gestational length variation on the degree of expression of the line. KEY WORDS: HUMAN BIRTH, DELIVERY MODE, GESTATION LENGTH, DECIDUOUS TEETH, DENTAL ENAMEL STRUCTURE, INCREMENTAL MARKERS, NEONATAL LINE.Pre-print version. Visit http://digitalcommons.wayne.edu/humbiol/ after 1 December 2011 to acquire final version. 2The birth process leaves its mark on dental enamel in the form of a ring, an accentuated incremental line called the "Neonatal Line" (NL) (Rushton 1933;Schour 1936). This prominent microfeature, occasionally visible also in the dentine (Schour 1936;Skinner 1992), separates the enamel formed during intrauterine life from that formed after leaving the womb.In modern humans, the NL is usually present in all crowns forming at birth, that is, all the elements of the primary dentition and the first permanent molars (mesiobuccal cusp) (Christensen and Kraus 1965, Deutsch andPe'er 1982;Deutsch et al. 1985;Kraus 1959;Levine et al. 1979). Occasionally, a macroscopic hypoplasia can be detected in correspondence with the NL, but it is usually worn away (Massler et al. 1941;Moss-Salentijn and Hendricks-Klyvert 1985;Schroeder 1991;Skinner 1992).At birth, the enamel is only partially mineralized and continues to increase in thickness by apposition of additional centripetal layers secreted by the ameloblasts at the level of the enamel-dentine junction (EDJ) to a circadian rhythm of 4-5 µm in extant humans (Antoine et al. 2...

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“…These defects generally correspond to the developmental stage and degree of insult as the primary teeth form and are most commonly present in the readily visible primary incisors, canines, and first molars. Both pre-and post-natal stresses adversely affect ameloblasts and odontoblasts during tooth formation and can result in both hypoplastic and hypomineralized enamel (Suckling, 1989;Sabel et al, 2008). The most common evidence of perinatal stress affecting tooth formation is found in virtually every child and presents subclinically as the neonatal line (NNL) .…”

Section: Enamel Hypoplasia (Ehp)mentioning

confidence: 99%

“…Histological findings reveal irregular crystalline formation along the lines of Retzius, sometimes accumulating on the surface perikymata as pits or lines (Seow et al, 2005;Sabel et al, 2008) (Fig. 2).…”

Section: Enamel Hypoplasia (Ehp)mentioning

confidence: 99%

Hypoplasia-associated Severe Early Childhood Caries – A Proposed Definition

2012

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A supplemental appendix to this article is published electronically only at http://jdr.sagepub.com/supplemental. AbstrActWe propose a new classification of severe early childhood caries (S-ECC): hypoplasia-associated severe early childhood caries (HAS-ECC). This form of caries affects mostly young children living at or below poverty, characterized by structurally damaged primary teeth that are particularly vulnerable to dental caries. These predisposing developmental dental defects are mainly permutations of enamel hypoplasia (EHP). Anthropologists and dental researchers consider EHP an indicator for infant and maternal stresses including malnutrition, a variety of illnesses, and adverse birthing conditions. Differentiation of HAS-ECC from other forms of early childhood caries is warranted because of its distinct etiology, clinical presentation, and eventual management. Defining HAS-ECC has important clinical implications: Therapies that control or prevent other types of caries are likely to be less effective with HAS-ECC because the structural integrity of the teeth is compromised prior to their emergence into the oral cavity. By the time these children present to the dentist, the treatment options often become limited to surgical management under general anesthesia. To prevent HAS-ECC, dentists must partner with other health providers to develop interventions that begin with pregnant mothers, with the aim of eliminating or ameliorating the covariates accompanying poverty, including better pre-and post-natal care and nutrition.

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Neonatal lines in the enamel of primary teeth—A morphological and scanning electron microscopic investigation

Cited by 94 publications

References 18 publications

Incremental enamel development in modern human deciduous anterior teeth

Incremental enamel development in modern human deciduous anterior teeth

Gestation Length, Mode of Delivery, and Neonatal Line-Thickness Variation

Hypoplasia-associated Severe Early Childhood Caries – A Proposed Definition

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