Chemical and structural composition of Atlantic Canadian moose (Alces alces) incisors with patterns of high breakage

Analysis of mammalian teeth can provide information regarding local environmental conditions. For example, a high incidence of breakage and wear within a population may indicate poor food quality. Individuals consuming a diet causing high mechanical stress on their teeth, and/or lacking the appropriate minerals for proper development, could experience degradation of tooth condition. Previously, we documented a high rate of incisor tooth breakage, with age, in two genetically distinct moose populations in Atlantic Canada. In this study, multi-element (¹¹B, ⁶³Cu, ⁶⁴Zn, ⁷⁵As, ⁸⁵Rb, ⁸⁸Sr, ¹¹¹Cd, ¹¹⁸Sn, ¹³⁷Ba, ²⁰⁸Pb, ²³²Th, and ²³⁸U) analyses using laser ablation ICP-MS were performed on moose incisors from multiple North American regions. The purpose was to determine whether the elemental composition of moose incisors varies among regions, and whether that variation is related to tooth degradation among Atlantic Canadian populations. A principal components analysis revealed that nearly 50% of the elemental variation in the inner enamel matrix of moose teeth was explained by three groupings of elements. The element groupings revealed differences among geographic regions, but did not explain the variation between incisors that were broken and those that were not. Regression models indicate that the elemental group which includes Cu, Pb, and Zn is related to decreases in incisal integrity. It is likely that other environmental factors contribute to the occurrence of increased incisor breakage in affected populations. The relationship between food resource quantity and quality, as a function of moose density, is hypothesized to explain loss of tooth integrity.