Root number determination in maxillary first premolars for modern human populations.

It is suggested that multiple root number of the maxillary first premolar be defined on the basis of lingual and buccal-root bifurcation greater than one-fourth to one-third (25%--33%) the buccal-root length. This meets pragmatic considerations and would enhance comparability of between-observer findings for an apparently independent trait of potential importance for population characterization, forensic identification, and microevolutionary analysis.