Two-point time-series of dental wear scores for baboon mandibular second molars

The pattern and rate of dental wear is often used in paleontology, paleoanthropology, and osteoarchaeology to infer age of the individual, abrasiveness of diet, masticatory function, etc. There are numerous hypotheses as to the relative impact of various parameters on the rate of dental wear in primates. However, these studies are complicated by the fact that most samples of dental wear are derived from wild populations. Here, we investigated the rate of molar wear in a captive colony of baboons (Papio hamadryas) from the Southwest National Primate Research Center (San Antonio, Texas). These animals lived in similar group cages and had access to the same uniform diet of monkey chow. Thereby, many of the potential contributing factors to tooth wear have been held constant. We investigated rate of wear with data from two time-points in the life of each animal. The first time-point was captured during life when the individual was anesthetized, a high-resolution dental mold was taken, and from which a high-resolution plaster cast was made. The second time-point was captured from the skeletonized skull of the individual after death. We made high-resolution oral scans of the plaster casts and the skulls. We characterized the occlusal wear using two different methods. First, we applied a modified wear scoring system that we developed for use on baboon molar morphology. We scored the wear for four quadrants of lower second molars for 202 individuals. The second method is the dentin exposure ratio (DER). With these data, we analyzed the rate of wear, sex, and age-by-sex effects. Our results indicate that males have higher wear scores on average than females, and that males have a higher rate of wear compared to females. We also found that the two buccal cusps had a higher correlation in wear score compared to the lingual cusps, and vice versa. When we consider the information that was gained from the the Krueger-Scott scores compared to DER, the DER measurements took much more time to collect and provided much less information about occlusal molar wear. 

Methods
We provide tab-delimited text files that contain the data analyzed for the published study.

For information on the scoring system, see Krueger et al. (2025).

The KruegerScottScore.txt file includes the sex, date-of-birth, date-of-death, date-of-dental-casting, and a qualitative score that reflects the degree of wear on each of the four quadrants of the mandibular second molar of 202 baboons from the captive colony at the Southwest National Primate Research Center (SNPRC). Individual baboons are refered to by W# (an identification number assigned to them when the skulls were incorporated into a collection then-curated at Washington University in St. Louis). The birth and death dates are from the SNPRC. The date of the dental-mold/dental-casting is from the records of Leslea Hlusko, as she took the molds in coordination with the SNPRC.

The scoring system was developed by Kristin Krueger, modifying the method of Scott (1979) to conform to the shape of baboons molars. The degree of wear was scored from 1 to 10, with 1 being the least worn, and 10 being the most worn. All scores were taken from high-resolution surface scans of the plaster casts (time-point-one) and the skulls (time-point-two). Details of the scoring method are reported in Krueger et al. (2025).

The dataset includes ages and the number of months between the two time-points. These values were calculated based on the dates also reported in the dataset. No other data processing has been done.

The DER.txt file includes the same W# for each individual, the anatomic side of the tooth measured, the dentine and occlusal areas at death (measurements from the skeletonized skulls), and the dentin and occlusal areas from the cast made during life ("cast"). 

Dentin and occlusal areas are reported in mm2. 

References:

Krueger, K.L., Towle, I., Matthews, G.J., Álvarez-Fernández, A., Hlusko, L.J. 2025. Tracking molar wear in captive baboons: sex and age effects using a modified Scott scoring system. American Journal of Biological Anthropology 188:e70126. DOI: 10.1002/ajpa.70126

Scott, E. C. 1979. “Dental Wear Scoring Technique.” American Journal of Physical Anthropology 51, no. 2: 213–218. DOI:10.1002/ajpa.1330510208