Surface Replication, Fidelity and Data Loss in Traditional Dental Microwear and Dental Microwear Texture Analysis

Matthew C Mihlbachler,Melissa Foy,Brian L Beatty

doi:10.1038/s41598-018-37682-5

Abstract

Dental microwear studies often analyze casts rather than original surfaces, although the information loss associated with reproduction is rarely considered. To investigate the sensitivity of high magnification (150x) microwear analysis to common surface replication materials and methods, we compared areal surface texture parameters (ISO 25178-2) and traditional microwear variables (pits and scratches) generated from teeth and casts of rat molars exposed to experimental diets involving hard and soft foods in which abrasive materials had been added. Although the data from the original and replicated surfaces were correlated, many significant differences were found between the resulting data of the casts and original teeth. Both areal surface texture parameters and traditional microwear variables showed diminished ability to discriminate between the eight diet treatments when casts were analyzed. When areal surface texture parameters and traditional microwear variables were combined into a single discriminant function analysis, the cast data and original data produced the most similar results. Microwear researchers tend to favor either texture analysis or traditional microwear methods, better results may be generated by combining them. Although surface textures were not accurately reproduced by the casts, they retained sufficient information to discriminate between microwear of the experimental diets to a degree similar to the original teeth.

Highlights

In this paper, we compare the dental microwear of original tooth surfaces and clear epoxy casts made from polyvinlysiloxane impression material (Fig. 1)
Dental casts were compared to the original tooth surfaces using both a traditional dental microwear method (TM) and dental microwear texture analysis (DMTA) using international standards relating to the analysis of 3D areal surface texture (ISO 25178-2)
The most strongly effected parameter, had a relative mean shift of 0.99, indicating the mean of the cast data was shifted from the original data to a degree that is nearly equal in magnitude to the standard deviation of the original data

Summary

Introduction

We compare the dental microwear of original tooth surfaces and clear epoxy casts made from polyvinlysiloxane impression material (Fig. 1). Prior studies attempted to compare epoxy casts generated from multiple impression materials including the Colténe Whaledent President Jet Product line, a product commonly used to generate molds for dental microwear research. We attempt to provide additional analysis of tooth replications made from Colténe Whaledent President Jet Regular Body impression material (for molds) and Epokwick Epoxy Resin (20-8136-128) and hardener (2020-8138-032) (for casts) using upper first molars (M1) of Rattus norvegicus that were divided into eight treatments based on different experimental diets (Mihlbachler et al in review). Microwear features on surface replications will have softened edges and rounder peaks and valleys due to the viscosity of the molding and casting compounds The effects that these changes have on resulting microwear data may depend on the method of microwear analysis. We hypothesize that ISO texture parameters most strongly associated with relief and angularity will be most strongly affected while parameters more closely related to orientation, size, overall shapes of indentation scars, and distances between them will be less affected (Fig. 2)

Methods

Results

Conclusion