Title of article :
Variability in cusp size of human maxillary molars, with particular reference to the hypocone
Author/Authors :
Takahashi، نويسنده , , Masami and Kondo، نويسنده , , Shintaro and Townsend، نويسنده , , Grant C. and Kanazawa، نويسنده , , Eisaku، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Abstract :
Objective
rpose of this study was to investigate cusp size variability in the human permanent maxillary first and second molars, with particular reference to the hypocone.
ere obtained from dental casts collected during a longitudinal growth study of Australian Aboriginals (148 males and 119 females), living at Yuendumu in Australia. Categorical data described the expression of the hypocone and quantitative data described the areas of the molar cusps, mesiodistal and buccolingual crown diameters, and overall crown areas. Several hypotheses relating to cuspal variation within and between M1 and M2 were tested using Chi-square tests, t-tests and ANOVA.
s
ttern of relative variation in maxillary molar cusp areas reflected the ontogeny of crown development, with earlier-forming cusps showing less variation than later-forming cusps. Sex differences in hypocone area were larger in M2s than in M1s and there was evidence of an interaction during development between the protocone and the hypocone in M2s. Those M2s with larger hypocones displayed larger crown areas and the hypocone of M1s tended to be smaller in individuals who displayed hypocone reduction in their M2s.
sions
ndings are consistent with the view that phenotypic variability within maxillary molar crowns is generated by dynamic interactions between developing cusps that form at different times and grow at different rates for different durations. Observed variation in cusp areas and hypocone expression between the maxillary M1 and M2 can also be explained in terms of differences in timing and duration of development of these teeth.
Keywords :
Cusp formation , Crown morphology , Dental reduction
Journal title :
Archives of Oral Biology
Journal title :
Archives of Oral Biology