The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)

The Application of 3D Geometric Morphometrics to Subadult Dentition: Exploring Tooth Development and Eruption Through Alternative Methods


Anthropology, University of Nevada, Reno

April 18, 2020 3:00PM, Diamond 8-9 Add to calendar

Dental age estimation is considered the most accurate method for subadults, but some imprecision in the age estimates may be due to the level of measurement. Documenting biological processes through continuous, interconnected data, rather than ordinal (development) or dichotomous data (eruption) may increase precision. The goal of this research is to compare the performance of variables evaluated with alternate levels of measurements.

A sample of 110 computed tomography scans from individuals between 3.0 and 8.0 years was used to collect 66 3D landmarks on the mandibular dentition. Landmarks were placed on the midline of each tooth at either two or three points: 1) crown apex, 2) maximum crown development up to crown complete, 3) maximum root length up to complete root. Interlandmark distances provided tooth length and relative position to alveolar bone.

The deciduous incisors had the lowest coefficients of variation (CV) (11.4%) and the second molar and fourth premolar had the highest CV (34.7% and 48.2%, respectively), which is likely linked to inconsistent crown initiation for M2 and P4 (~50% were absent in 3 year olds). Significant (p<0.05) right-left asymmetry was found in the deciduous canine and central incisor. Visual analysis in 3D space and principal component analysis demonstrated that delayed development and the direction of growth accounted for 37% of variance after Procrustes alignment. Continuous data yielded more precise estimates than ordinal data using a mixed cumulative probit. Results indicate that alternative methods for development and eruption can improve the precision of dental age estimations.