Tooth wear and dental calculus in a group of orca (Orcinus orca) stranded on the New Zealand southern coast.

In 2014, a group of nine orca stranded in Te Waewae Bay, Western Southland, and their remains were collected, processed and studied in partnership with Ōraka Aparima Rūnaka. A total of 436 teeth were analysed to determine the location, type and intensity scores of tooth wear. The presence of dental calculus and percentage surface coverage was assessed on 1744 surfaces. Tooth wear and calculus were investigated in relation to sex and total body length (as a proxy for age). All orca had some degree of tooth wear; however, most teeth were worn superficially. Only two individuals had severe wear as the most common wear type; nonetheless, no exposure of the pulp cavity was observed. There were slightly lower wear scores in the upper dentition and wear scores were associated with body length. Calculus varied within and between orca, with eight of the nine having calculus deposits present. More calculus was found on the upper dentition on mesial and buccal aspects. Despite the limited number of individuals analysed here, the opportunity to investigate patterns of tooth wear and calculus in a group of nine wild orca was enabled by the research partnership with significant support of the local community.