Smooth operator: The effects of different 3D mesh retriangulation protocols on the computation of Dirichlet normal energy

Abstract

Different retriangulation protocols yield different DNE values for the same surfaces, and should not be combined in meta-analyses. Increasing face count will capture surface microfeatures, but at the expense of computational speed. More aggressive smoothing is more likely to alter the essential geometry of the surface. A protocol is proposed that limits potential artifacts created during surface production while preserving pertinent features on the occlusal surface.

The case of the grass‐eating suids in the Plio‐Pleistocene Turkana Basin: 3D dental topography in relation to diet in extant and fossil pigs

“…Other studies have used 50 data rows for one tooth (Smits & Evans, ; Winchester et al, ). For “molaR,” which uses the 3D‐meshes instead of raster files, the face count of the mesh was reduced to 10,000 and Laplacian smoothing (three steps) was done in MeshLab (Boyer, ; Bunn et al, ; Pampush et al, ; Spradley, Pampush, Morse, & Kay, ). JMP Pro 13 (SAS Institute Inc., Cary, NC) was used to perform the statistical analyses.…”

Technical note: Comparing dental topography software using platyrrhine molars

“…A subset of platyrrhine upper second molar (M 2 ) scans produced by Ungar et al () were reused in this study (see Table for inventory). PLY files generally conforming to the established standards for DNE mesh analyses were produced (see Bunn et al, ; Pampush et al, , , ; Spradley et al, ; Winchester et al, ) following a multistep conversion process detailed in the supplemental materials. One frequently used metric, Relief Index (RFI see: Boyer, ) was not included in the analyses because the scans used here did not include the entire sidewalls of the teeth, as is required for the RFI calculation.…”

“…To derive these topography measures from dental crowns, the crown or casts of the crown are scanned, processed into digital models, and then analyzed by one of several software packages (for overview see Spradley, Pampush, Morse, & Kay, ). Despite attempts to standardize these measurements (Pampush et al, ; Spradley et al, ), there remain idiosyncrasies associated with different research groups, partly arising out of their chosen analytical software. Four software packages are used to calculate one or several of the five noted metrics.…”

Functional morphology in the pages of the AJPA

“…Another method first described in the AJPA is the Dirichlet normal energy technique (Bunn et al, ), one of a number of new “dental topographic” methods (orientation patch count, relief index) (Evans, Wilson, Fortelius, & Jernvall, ; Ungar & M'Kirera, ) that have become widely used. Such approaches offer great promise in refining our understanding of relationships between dental morphology, diet, and ecology (Godfrey, Winchester, King, Boyer, & Jernvall, ; Spradley, Pampush, Morse, & Kay, ; Winchester et al, ). It is noteworthy that, as with recent advances in skeletal modeling, these new approaches have largely been made feasible by technological improvements, in particular the more widespread availability of micro‐CT and surface scanners.…”