A light microscopic and ultrastructural examination of calcified dental tissues of horses: 1. The occlusal surface and enamel thickness.

The research examines the structure and characteristics of horse teeth at macroscopic and microscopic levels, revealing various patterns, variations, and descriptions pertaining to their anatomy and potential wear.

Methodology

• The researchers conducted gross and microscopic examinations on a total of 50 horse teeth – 46 cheek (molar and premolar) and 4 incisor teeth. These teeth were either naturally fractured or systematically sectioned.
• The chosen horse teeth were examined in three different states: untreated, after acid etching, and after decalcification.
• The examination used a combination of light, scanning, and transmission electron microscopy. These techniques allowed the researchers to gain a clear, detailed image of the various component parts of the teeth, including the occlusal surfaces and enamel thickness.

Findings

• The study found that an organic pellicle, a coating of salivary proteins, often covers the occlusal surface of horse teeth, the part of the tooth that comes into contact with other teeth when the mouth is closed.
• The occlusal surface displayed varying wear patterns, including polished areas, local fractures, wedge-shaped pits, striations, and depressions.
• The occlusal dentine, the underlying layers of the teeth, exhibited depressions that correlated with its occlusal surface area – larger surface areas had deeper depressions.
• The study also found variability in the thickness of equine enamel along the folds of the transverse plane. It was noted that the enamel was thickest in those areas where the folds were parallel to the tooth’s long axis.
• Enamel thickness was constant in the longitudinal plane—that is, the aligning length of the tooth.
• The study also observed that the peripheral enamel in lower teeth was more deeply infolded compared to upper teeth, which was hypothesized to compensate for the absence of infundibula—deep enamel indentations.