Pediatric dentistry is generally defined as the dental care of animals from birth to about 1 year of age. At 1 year of age, the permanent dentition has matured and adult dental issues begin. This article focuses on the more common oral and dental problems diagnosed during the pediatric dental period. Some of these problems are quite similar to problems seen in adult patients, while others are confined to younger patients.
PERSISTENT DECIDUOUS DENTITION
The most common pediatric dentistry problem is persistent deciduous teeth (previously known as retained deciduous teeth).1 A deciduous tooth is considered persistent as soon as the permanent tooth begins to erupt into the mouth.
Cause and predisposition
The most frequent cause of deciduous tooth persistence is an incorrect eruption path of the permanent tooth.2 When the permanent tooth erupts along its natural path, it places pressure on the apex of the deciduous tooth, resulting in deciduous root end resorption.3 This resorption progresses until the deciduous tooth exfoliates and the permanent tooth assumes its normal position in the mouth. When the permanent tooth follows an incorrect path, there will be no impetus for deciduous root resorption, resulting in the deciduous tooth's retention and the permanent tooth's eruption alongside.
Because of the pattern of occurrence, especially within certain breeds and head types, persistent deciduous teeth are generally viewed as a genetic problem.2 This view counters the mistaken belief that the persistent deciduous tooth caused the permanent tooth to erupt in an unnatural position.
Other causes of persistent deciduous dentition are rare but include primary impaction or ankylosis of the deciduous tooth. These conditions will not allow for normal exfoliation and result in either impaction or improper eruption of the permanent tooth.2
Persistent deciduous dentition occurs most often in toy- and small-breed dogs but can be seen in any breed as well as in cats. The most common deciduous teeth to become persistent are the cuspids (previously known as canines), followed by the incisors and then the premolars.2
An oral examination will reveal extra teeth in the arcades (Figure 1). This extra dentition is typically bilateral and results in crowding. In addition, the permanent dentition will be in an abnormal position, which may cause dental, gingival, or palatine trauma. Orthodontic changes can occur within two weeks of the first sign of eruption of the permanent dentition.2
Because the deciduous tooth and the permanent tooth share the same gingival attachment, the permanent tooth is not allowed to develop a normal gingival attachment, resulting in susceptibility to periodontal disease.2 Patients that tend to retain teeth (e.g. toy- and small-breed dogs) are also prone to developing periodontal disease in general.
In animals with persistent deciduous teeth, the permanent tooth does not need to be completely erupted for orthodontic and periodontal problems to occur. In fact, the problems start as soon as the permanent tooth begins to erupt.
All persistent deciduous teeth must be extracted as early as possible to lessen the untoward effects.2,4 The age at eruption of permanent incisors, cuspids, and premolars is between 3 and 6 months,4 which approximately parallels the timing of the last vaccination in most puppy or kitten immunization series. Therefore, it is strongly recommended that an oral evaluation accompany this visit. In addition, instruct owners to examine their pets' mouths on a regular basis to help ensure the prompt detection and removal of these teeth. Because damage begins shortly after eruption of the permanent tooth, it is not recommended to wait to perform deciduous tooth extraction along with an ovariohysterectomy or orchiectomy.
Obtain a diagnostic dental radiograph to help differentiate the deciduous teeth from permanent dentition in questionable cases. Radiographs will also confirm the integrity of the root structure of the deciduous teeth (Figure 2).