Developmental enamel defects represent not only a cosmetic alteration of the crown of teeth in dogs, but, more important,
the brown-to-tan discoloration indicates that the underlying dentin may be exposed to the oral environment (Photo 1). This
exposure can lead to pulpitits and death of the affected tooth or teeth. Dentin sensitivity is a concern, especially if multiple
teeth are affected.
Photo 1: A developmental enamel defect in the right mandibular first molar in a dog. Note the tan-to-brown discoloration.
(Photos courtesy of Dr. Brett Beckman)
Root aberrations may also occur that may require treatment (Photo 2). Dental radiography, therefore, is paramount in assessing
all teeth with enamel defects, regardless of cause.
Photo 2: Concurrent alterations in the dentin formation in teeth with enamel defects may result in root abnormalities. Note
the shortened and apically thin mesial root of the right mandibular first molar in this dog.
Developmental enamel defects can be categorized based on compromise of quality or quantity. Defects in quality (hypocalcification)
cause a less inorganic matrix, and the resulting enamel is softer than normal enamel. It's often possible to remove hypocalcified
enamel with ultrasonic scaling.1 Defects in quantity (hypoplasia) result in a much thinner than normal enamel.1 Pitting may be present in the surface. Both types of defects can be found concurrently, and differentiation is not necessary
because, therapeutically, the approach is the same.
Many teeth with developmental enamel defects also will have variations in developmental root abnormalities. Roots may appear
long and thin toward the apex (Photo 3,) or have blunt attenuated roots (Photo 4).
Photo 3: Thinning at the apex is present in this dog’s left mandibular canine tooth.
In addition, amelogenesis imperfecta is an inherited maturation disorder of the enamel. This condition appears to be uncommon
in dogs, although standard poodles may have a genetic predisposition.2
Photo 4: Attenuation and blunting are present in this dog’s left first and second molar teeth.
Enamel formation occurs in dogs between 2 weeks and 3 months of age.3 Trauma during enamel development is a common cause of enamel defects in dogs. However, in general, a history of oral trauma
is nonexistent but, occasionally, can be traced to altercations with other pets or accidental drops, falls, etc. The result
is generally seen in one or several teeth in a regional distribution. A febrile event that occurred during enamel development
may be responsible for cases in which most or all of the dentition is affected.
Systemic insults that may result in enamel defects include nutritional deficiencies, infection, fever, metabolic abnormalities,
toxins and parasites. Distemper viral infections and other Morbillivirus species infections are classically recognized as causes of enamel hypoplasia or hypocalcification.4