Calcified Deposits on Sheep Incisor Teeth

¹ Dental Research Unit, New Zealand Medical Research Council, Wellington, New Zealand, and Soil Bureau, Department of Scientific and Industrial Research, Lower Hutt, New Zealand

A hard deposit occurring on the labial surface of incisor teeth of sheep grazing on pasture in one area of New Zealand was studied.

Chemical and X-ray diffraction studies showed the deposit to be a well-calcified, noncrystalline or poorly crystalline material composed of 20.3 percent crude protein, 27.6 percent Ca, 10.2 percent P, 0.9 percent Mg, and trace amounts of Cu, Si, Al, Zn, Ba, Sr, Ti, Pb, Fe, and Mn.

Histologic study showed a concentric arrangement of the calcified material around macroscopic channels or cavities and a regular distribution of microscopic lacunas within the material.

It was concluded that the calcified deposit of unknown etiology had a mineral composition compatible with a calculus or cementum origin, but histologically was similar to bone.