title: The effect of the season of birth and of selected maternal factors on linear enamel thickness in modern human deciduous incisors.
abstract: OBJECTIVE
  Development of human tooth enamel is a part of a foetus's development; its correctness is the outcome of genetic and maternal factors shaping its prenatal environment. Many authors reported that individuals born in different seasons experience different early developmental conditions during pregnancy. In this study, we investigated the effects of season of birth and selected maternal factors on enamel thickness of deciduous incisors.
  
  
  METHODS
  Dental sample comprises 60 deciduous incisors. The parents who handed over their children's teeth for research fill in questionnaires containing questions about the course of pregnancy. All teeth were sectioned in the labio-linqual plane using diamond blade (Buechler IsoMet 1000). The final specimens were observed by way of scanning electron microscopy at magnifications 80× and 320×. The thickness of total enamel (TE), prenatally (PE) and postnatally (PSE) formed enamel was measured.
  
  
  RESULTS
  Children born in summer and in spring (whose first and second foetal life fall on autumn and winter) have the thinnest enamel. Season of birth, number of children in family, diseases and spasmolytic medicines using by mother during pregnancy explained almost 13% of the variability of TE. Regression analysis proved a significant influence of the season of birth and selected maternal factors on the PE thickness - these factors explained over 17% of its variability. Neither of analysed variables had influenced PSE.
  
  
  CONCLUSIONS
  Our findings suggests that the thickness of enamel of deciduous incisors depends on the season of birth and some maternal factors. The differences were observed only in the prenatally formed enamel.
authors.affiliation: Department of Anthropology, Faculty of Biology and Environmental Protection, University of Łódź, Banacha-Str. 12/16, 90-237 Łódź, Poland. e.zadzinska@biol.uni.lodz.pl
authors.forename: E
authors.initials: E
authors.lastname: Żądzińska
authors.forename: M
authors.initials: M
authors.lastname: Kurek
authors.forename: B
authors.initials: B
authors.lastname: Borowska-Strugińska
authors.forename: W
authors.initials: W
authors.lastname: Lorkiewicz
authors.forename: I
authors.initials: I
authors.lastname: Rosset
authors.forename: A
authors.initials: A
authors.lastname: Sitek
mesh_terms: D000566:Amelogenesis / Q000502:physiology; D001722:Birth Order; D002648:Child; D002675:Child, Preschool; D036861:Delivery, Obstetric; D003743:Dental Enamel / Q000033:anatomy & histology* / Q000648:ultrastructure; D019587:Dietary Supplements / Q000145:classification; D005260:Female; D005865:Gestational Age; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology* / Q000648:ultrastructure; D058085:Iron Compounds / Q000627:therapeutic use; D008297:Male; D008423:Maternal Age; D008855:Microscopy, Electron, Scanning; D010276:Parasympatholytics / Q000627:therapeutic use; D010298:Parity; D036801:Parturition / Q000502:physiology*; D011247:Pregnancy; D011248:Pregnancy Complications; D012621:Seasons; D057566:Self Report; D014094:Tooth, Deciduous / Q000033:anatomy & histology* / Q000648:ultrastructure; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D058085:Iron Compounds; D010276:Parasympatholytics; D014815:Vitamins