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PRACTICAL DENTISTRY | A B C Figure 1. (A) Peripheral odontogenic fibroma on the maxilla of a dog; (B) ossifying peripheral odontogenic fibroma on the maxilla of a dog; (C) intraoral radiograph of the patient in A. Note the lack of bony reaction; however, a crown fracture is present (arrow). A B Figure 2. (A) Clas- sic "fleshy" appearance of an acan- thomatous ameloblas- toma on the mandibular incisor region of a dog; (B) intraoral radio- graph of the patient in A; note the sig- nificant bony destruction. and squamous cell carcinomas (Figure 7, page 54) are also seen in dogs. Cysts Cysts are a subset of oral masses: UÊDentigerous cysts (Figure 8, page 54) are the most common cysts, which arise from the enamel-forming organ of an impacted tooth.1 They are most commonly found in mandibular first premolars of brachycephalic breeds. Their incidence in veterinary medicine has not been documented, but anecdotally they are found in approximately 50% of embedded teeth. UÊRadicular cysts (Figure 9, page 54) are another type of cyst that develops from embryonic tissue remains, usu- ally due to an inflammatory stimulus from the tooth. As cysts grow, they cause bone loss by pressure.8 They can grow quite large in a short period of time, quickly resulting in weakened bone. A B Figure 3. (A) Proliferative squamous cell carci- noma on the buccal mucosa of a cat; (B) destructive squamous cell carci- noma on the palate of a cat. DIAGNOSIS During routine physical examinations, an oral examination should be performed. Any oral masses are cause for concern (especially in felines) and should prompt a dental procedure and biopsy or, at minimum, very careful monitoring. Clinical cues help determine the type of oral growth: In my experience, malignant growths tend to invade the tissues; benign growths tend to be more proliferative. However, because clinical examination of masses is unreliable, dental radiographs and biopsies should be performed for all oral masses. Imaging Most benign neoplastic growths (Figure 10, page 54) have no boney involvement on dental radiographs.6,8 UÊ vÊ LoniÊ inÛolÛiminÌÊ `oiÃÊ oVVÕÀ]Ê iÌÊ iÃÊ iÝ«>nÃiÛipÌhiÊ bone "pulls away" from the advancing tumor, leaving a `iV>lVivii`]Ê ÃovÌpÌiÃÃÕi-villi`Ê Ã«>ViÊ Figures 11A and 11B, page 54).6,8 UÊ onÞÊm>À}inÃÊ>ÀiÊÕÃÕ>llÞÊ`iÃÌinVÌ°ÊÊÊÊ UÊ/hiÃiÊÌÞ«iÃÊovÊiÝ«>nÃiÛiÊ}ÀoÜÌhÃÊÌÞ«iV>llÞÊV>ÕÃiÊÌooÌhÊ movement (Figures 11B and 11C, page 54).8 Malignant oral neoplasms typically invade bone early in the course of disease, resulting in irregular, ragged bone July/August 2012 Today's Veterinary Practice 53 Introduction to Oral Neoplasia in the Dog & Cat