Dentistry 101: Surfaces of teeth and directions in the mouth

This month's column is set up as a photo tutorial. The goal is to offer some basic instruction about veterinary dentistry and its terminology. Here are some common terms and images associated with these key concepts.

Rostral and caudal

Rostral refers to a structure closer to, or in a direction toward, the most forward structure of the head. Caudal refers to a structure closer to, or in a direction toward, the tail.

The retained deciduous canine in Photo 1 is caudal to the adult canine.

Photo 1

Mesial and distal

The mesial surface of the first incisor is next to the median plane; on other teeth it is the surface directed toward the first incisor (the surface adjacent to the tooth in front of it). The distal surface is opposite from the mesial surface.

Photo 2A

Mesial and distal are labeled in Photos 2A and 2B. The mesial root of the maxillary fourth premolar in Photo 2B is affected by stage 4 periodontal disease.

Photo 2B

Lingual, palatal, vestibular, buccal and labial

The surface of a mandibular or maxillary tooth facing the tongue is the lingual surface. Palatal can also be used when referring to the lingual surface of maxillary teeth.

Vestibular is the correct term referring to the surface of the tooth facing the vestibule or lips; buccal and labial are acceptable alternatives.

Photo 3A

Lingual, palatal, vestibular, buccal and labial are labeled in Photos 3A and 3B.

Photo 3B

Combination for triple-rooted teeth

The maxillary fourth premolar has three roots — the mesiobuccal, mesiopalatal and distal. In dogs, the maxillary first molar tooth has three roots — the mesiobuccal, distobuccal and palatal.

Photo 4A

The mesiobuccal root of the left maxillary fourth premolar in Photo 4A is fractured. The palatal root of the maxillary first molar in Photo 4B is discolored secondary to pulpitis.

Photo 4B

Dr. Bellows owns Hometown Animal Hospital and Dental Clinic in Weston, Fla. He is a diplomate of the American Veterinary Dental College and the American Board of Veterinary Practitioners. He can be reached at (954) 349-5800; e-mail: dentalvet@aol.com.