Pathological studies of cheek teeth apical infections in the horse: 2. Quantitative measurements in normal equine dentine.

The research investigates the measurements of various types of dentine and pulp dimensions in horse’s cheek teeth (CT) across different ages. The study noted an age-related increase in dentine thickness in both maxillary and mandibular CT, with variations found depending on tooth location and individual pulp horns.

Methodology and Measurements

• The researchers took measurements from transverse, sub-occlusal, and mid-tooth sections of both maxillary and mandibular control CT in horses of different ages.
• The dimensions they measured included primary, regular and irregular secondary dentine, and pulp dimensions.
• In total, 40 maxillary and 42 mandibular CT were examined.

Findings: Primary Dentine

• Maxillary and mandibular CT primary dentine had a mean thickness range of 922-1,065 microm and 1099-1,179 microm on the lateral aspects, and 1,574-2,035 microm and 1155-1,330 microm on the medial aspects of pulp horns.
• Interestingly, the researchers found a minor increase in thickness in mandibular CT primary enamel in the first few years following tooth eruption.

Findings: Secondary Dentine

• Regular secondary dentine thickness increased with dental age, being thicker in the sub-occlusal region compared to the mid-tooth region.
• At the middle tooth level in mandibular CT, thickness ranged from 124 microm at 3 years dental age to 290 microm at more than 7 years dental age on the lateral aspects of pulp horns, and from 166 microm to 509 microm on the medial aspects of pulp horns.
• The researchers concluded that this indicates a deposition rate of 0.5-10 microm/day.

Other Observations

• Maxillary CT dentine was significantly thicker (72% in primary, 43% in regular secondary dentine) on the medial compared to the lateral aspects of pulp horns.
• Conversely, mandibular CT dentine was just 15% and 14% thicker in primary and regular secondary dentine thickness, respectively, on their medial in comparison to their lateral aspects.
• Dentinal and pulp dimensions varied among individual pulp horns, tooth position according to the Triadan system, and with dental age.
• There were complex interactions between these variables for some parameters, indicating that factors such as tooth position and the individual horse’s dental age factor into the final dimensions.