A Study of Cusp Base Areas in the Maxillary Permanent Molars of American Whites

Dustin P Dinh,Edward F Harris

doi:10.26575/daj.v18i1.130

Abstract

The focus of this descriptive study was toexplore the patterns of variation of base crown areas forthe four major cusps on the maxillary first and secondpermanent molars in a cohort of contemporary NorthAmerican whites of western European descent. Acomputer-assisted photogrammetric method was usedto measure two-dimensional areas of the cusps. Rankingof mean cusp size was the same for M1 and M2, namelyprotocone > paracone > metacone > hypocone. In concertwith field theory, size decreased while variability (CV)increased across this same sequence. Overall area of M1(97 mm2) is 13% larger than M2 (86 mm2) in this sample.Most cusps exhibited significant sexual dimorphism,with greater differences for the distal cusps within atooth and from M1 to M2. Intercorrelations of cusp areaswere notably low (r2 < 15%) both within and betweenM1 and M2, suggesting considerable independence informative rates of each cusp and low morphologicalintegration of these constituents of the occlusal table.Limited comparative material in the literature suggeststhat cusp areas may valuably extend the quantitativecomparisons for genetic and biological studies beyondconventional tooth crown width and length.

Highlights

The focus of this descriptive study was to explore the patterns of variation of base crown areas for the four major cusps on the maxillary first and second permanent molars in a cohort of contemporary North American whites of western European descent
Researchers have investigated other sorts of tooth crown variables, notably Biggerstaff (1969a,b) who devised an array of distances, angles, and areas that can be measured on the occlusal table of teeth in the buccal segments
Considerable importance now is attributed to primary and secondary enamel knots that direct the folding of the inner enamel epithelium (IEE) that determines a tooth’s crown morphology (Jernvall et al, 1994; Thesleff et al, 2001)

Summary

Introduction

The focus of this descriptive study was to explore the patterns of variation of base crown areas for the four major cusps on the maxillary first and second permanent molars in a cohort of contemporary North American whites of western European descent. Researchers have investigated other sorts of tooth crown variables, notably Biggerstaff (1969a,b) who devised an array of distances, angles, and areas that can be measured on the occlusal table of teeth in the buccal segments. As with some previous researchers (e.g., Biggerstaff, 1975; Corruccini, 1979; Townsend, 1985; Townsend et al, 2003; Bailey, 2004), we were motivated to explore the patterns of variation of the occlusal tables of maxillary molars, largely to investigate whether additional information can be gained compared to the conventional lengths and widths of crowns. Macho and Moggi-Cecchi (1992), Bailey (2004) and others used computer systems that obviate the tedium of semi-mechanical approaches

Methods

Results

Conclusion