Occlusal fissures in equine cheek teeth: μCT and histological findings.

This research looked at fissures, or cracks, on the surface of horse cheek teeth. Techniques used included high-resolution X-ray imaging and a careful examination of the structure and makeup of the teeth. The researchers found the fissures can provide a route for microorganisms to cause inflammation in the dental pulp, but in healthy teeth, increased production of a type of dentin can create a defensive seal.

Research Study and Methodology

• The study investigated fissures on the occlusal (chewing) surface of equine cheek teeth. These fissures are usually considered abnormal, but their exact cause, development, and impact on pulp diseases remain uncertain.
• Twenty-seven teeth from fifteen horses were scanned using high-resolution X-ray computed tomography imaging (µCT), a non-destructive method for obtaining high-resolution, three-dimensional images that allows researchers to analyze the full extent of the fissures inside the teeth.
• The study also utilized histology (the study of the microscopic anatomy of cells and tissues) to investigate the physical characteristics and materials inside the fissures.

Findings and Observations

• Forty-three type 1 fissures were identified in the teeth scanned. They were further subdivided into type 1a (35 instances) and type 1b (eight instances), with varying mean lengths and depths.
• The histological examination revealed the presence of organic material inside the fissures, with microorganisms extending into the dentinal tubules (small, tube-like structures in the dentin), suggesting that these fissures may provide a pathway for microorganisms to infiltrate the teeth.
• The presence of reactionary dentin (also known as tertiary dentin), a special type of dentin produced in response to stimuli or damage, was also observed. This could suggest a natural defensive reaction in healthy teeth to seal off potential infection routes.

Conclusions and Implications

• Multiple factors, including the fissure’s location and the Triadan number (a widely used dental numbering system), were found to be significantly associated with fissure depth.
• The study suggests that fissures could potentially lead to pulpal inflammation by allowing microorganisms to infiltrate the dental tubules.
• In healthy teeth, the odontoblasts (cells that produce dentin) seem to respond by producing reactionary dentin, which lacks open tubules and could therefore provide a proper seal against microorganisms.