Predicting Mandibular Canal Height

Oral diseases are common in cats, and tooth extraction is the most common procedure performed in feline dentistry. This study sought: 

• To characterize the mandible height, mandibular canal height, and distance between the interdental alveolar margin and the mandibular canal.
• To use a patient’s age, weight, and canine tooth width at the free gingival margin level (wCGM), which was easily available during oral examination, to develop a mathematical model to predict the patient’s mandibular canal height.

Client-owned cats (n = 33) were enrolled. Right and left lateral digital skull radiographs were taken, and anatomic measurements of mandibular structures between the third molar distal root and the fourth premolar proximal root were obtained. The authors found a strong correlation between the wCGM obtained during physical examination and the radiographic measurements of the mandible height. This allowed for development of a mathematical model with a high predictive capability and low standard of error for mandibular canal height in cats. 

The authors indicated that this mathematical model provides clinicians with additional information about the relationships between different mandibular structures, thus potentially reducing the risk for iatrogenic lesions during oral surgery. 

Cephalometric analysis involves clinically applying the relationship from measurements between various dental and anatomic structures in the head. Whereas cephalometry has many applications in orthodontics and oral surgery in humans, limited information exists in veterinary medicine. These limitations likely exist because of the wide variation in skull shapes among breeds. The conclusions from this study suggested that cephalometric analysis is accurate to determine mandibular canal height in cats. The ability to calculate this dimension may be most clinically useful when assessing the feasibility for placement of fracture fixation devices using screws, pins, or wires while trying to avoid the mandibular canal. Avoiding the mandibular canal is important because iatrogenic damage to the canal contents risks profuse hemorrhage or irreversible damage to the blood supply of vital teeth. On a broader level, the results validated that reliable methods can be discerned to establish, calculate, and predict the location or relationship of important anatomic structures.—Christopher Snyder, DVM, DAVDC