Prevalence and Patterns of Tooth Wear in Pre-contemporary Australians

Objectives: Tooth wear is a multifactorial process that has affected human dentitions throughout history. Our aim was to determine the prevalence and pattern of tooth wear, and to conduct microwear texture analysis, in a pre-contemporary Australian Aboriginal Narungga tribe from the Yorke Penninsula, South Australia. We hypothesized that microwear texture parameters, including complexity (surface roughness) and anisotropy (scratch directionality), would vary between different wear types.
Methods: Forty-seven pre-contemporary skulls dated to pre-European settlement were examined, including 28 males, 14 females and 5 of unknown sex. The skulls were divided into four age groups (<20, 20-35, 35-50 and 50+ years) and tooth wear was assessed using an ordinal scale described by Scott (Am J Phys Anthropol 1979; 51: 213-217). Wear types were categorized into three groups according to the predominant wear processes including ‘mainly abrasion’ (from foreign bodies), ‘mainly attrition’ (from tooth grinding) and combined ‘abrasion-attrition’. Microwear texture analysis was conducted on 20 teeth from each wear group.
Results: Non-carious cervical lesions were not observed in any skull. The median wear scores (interquartile range) on incisal and occlusal surfaces were 1.78 (1.71-1.85), 3.93 (3.26-5.24), 6.20 (4.59-7.36) and 7.86 (7.09-8.64) for the four age-groups, respectively. There was a significant effect of age on wear scores (p<0.001), but not of sex (p>0.05). Of 18 subjects in whom wear pattern could be assessed, 4 (22.2%) displayed abrasion, 2 (11.1%) displayed attrition and 12 (66.7%) displayed abrasion-attrition. Overall, attrition showed significantly higher values for anisotropy (median, interquartile range; 0.0025, 0.0021 – 0.0030) compared to abrasion (0.0018, 0.0015 – 0.0020) (p<0.001), but there were no significant differences in complexity (p>0.05).
Conclusions: Our findings show a strong indication that tooth grinding occurred in this pre-contemporary Australian population. More detailed microwear texture analysis could be useful in providing insights into the culture and lifestyle of pre-contemporary populations.