Oral pathology-part 2 (Proceedings)

In the previous lecture, the importance of being able to identify periodontal indices was discussed as well as the importance of correctly recording that pathology on dental charts. The indices most commonly evaluated are gingivitis, probe depth, gingival recession, furcation involvement, mobility and periodontal attachment. These indices are the factors along with radiographs that are involved in grading periodontal disease.

As important as the periodontal indices are in the diagnosis and grading of periodontal disease, there are many other pathologies that may be encountered during a thorough oral examination. It is important to be able to recognize these anomalies and bring them to the attention of the veterinarian.

Stomatitis:

Lymphoplasmacytic Stomatitis (LPS) is a chronic, painful condition that can be very difficult to diagnose and treat. Multiple tests are needed to rule out other problems. Make sure the animal is FeLV/FIV negative, you may want to consider Bartonella testing. Most treatments are ineffective; to date the best treatment is a complete dental extraction including the removal of all dentin. This treatment is usually effective in about 80% of the cases.

Feline odontoclastic resorptive lesions (forl):

FORL's can be difficult to classify. There are five stages of FORL's that are determined by the amount of crown involved n the lesion.

     • Stage 1

           Lesions extend only into the cementum. This stage occurs only subgingivally. – Very difficult to detect

     • Stage 2

           Lesions progress through the cementum into the dentin of the root or crown but the pulp is not exposed. Hyperplastic gingiva may cover these defects.

     • Stage 3

           Lesions progress into the pulp chamber. Bleeding on probing and spontaneous fractures of the crown may occur.

     • Stage 4

           Lesions destroy a significant amount of the crown.

     • Stage 5

           Lesions have significant root replacement resorption with healing of the gingiva. There will not be any clinically apparent tooth tissue.

In addition to the stages of FORL's, they can be classified based on radiographic appearance of the periodontal ligament space:

     • Type 1 – Lesions are caused by inflammation. The root appears normal, and the periodontal ligament space is still observable.

     • Type 2 – The affected tooth is ankylosed to the alveolus. This type of lesion is not associated with periodontal disease

Chronic alveolar osteitis:

This condition commonly is associated the maxillary canines of cats. It produces a pronounced bulging appearance of the osseous tissue at the upper canines. Suspicious tissue should be biopsied, but in most cases this condition is the result of chronic inflammation. Periodontal pockets may be present and the teeth should be treated appropriately. There may be sufficient inflammation and loss of attachment to warrant extraction.

Maxillary canine extrusion:

In conjunction with chronic alveolar osteitis or alone, cats can have a unique response where the maxillary canine teeth appear to extrude. The teeth appear longer than normal and have an increased amount of gingival extrusion. The extruded teeth may also cause trauma to the lower lip. If the tooth is not mobile, does not have periodontal pockets or radiographic signs of excessive bone loss they can be saved. It may be necessary to blunt the tips of these canines to minimize lip trauma.

Discolored teeth:

Discolored teeth should be thoroughly evaluated to determine if the discoloration is due to extrinsic or intrinsic staining. Extrinsic staining comes from accumulations on the surface. Intrinsic stains are secondary to endogenous factors that discolor the underlying dentin. Transillumination with a fiberoptic light can assist in distinguishing between vital and necrotic pulp. Radiographs of affected teeth can be very useful in identifying pathology associated with discolored teeth.

Malocclusions:

As stated earlier, malocclusions need to be charted. Any variation from the standard occlusion is considered a malocclusion. A normal occlusion is called a scissor-incisor bite. The lower canine teeth fit evenly between the upper canine and the third incisor. Premolars are in a pinking-shears configuration where the cusps of the mandibular premolars point direction the interdigital spaces of the maxillary premolars with the cusps overlapping in a horizontal plane. There are four classifications of malocclusions:

     • Class 1

           The jaws are in perfect proportion with each other however the cause of these abnormalities can be retained deciduous teeth, anterior crossbites, narrow base canines, lance canines, posterior crossbites.

     • Class 2

           Overbite, either the mandible is short in relationship to the maxilla (mandibular brachygnathism) or the maxilla is too long (maxillary prognathism).

     • Class 3

           Underbite, the mandible is too long (mandibular prognathism) but more often the maxilla is too short (maxillary brachygnathism or brachycephalic)

     • Class 4

           Wrybite – one quadrant experiences abnormal growth either too long or too short. The midline is altered

Along with malocclusion, tooth crowding, rotated, supernumary or missing teeth and attrition or the wear of teeth due to an improper bite is important to record. Retained deciduous teeth also need to be noted.

Fractured, missing & extracted teeth:

Fractured, missing, extracted teeth should also be recorded on the chart. There are many other abnormalities that should be recorded on the chart. Fractured teeth and the type of fracture are critical to record.

Oral and gingival masses:

Oral masses need to drawn onto the chart and noted. This includes epuli and gingival hyperplasia. Epulides arise from the periodontal ligament. This is important to note these in order to have a record of the mass and be able to note changes in future examinations as well as gingivectomies or the removal of excess gingival tissues.

Gum-Chewers lesions are caused by self-inflicted trauma as a result of the animal chewing on the inside of the cheek to the tongue. These lesions cause the proliferative, granulomatous hyperplasia to occur. The lesions can be mild to serious that involve large amounts of tissue than can cause regular hemorrhages and be painful.

All surfaces of the tongue should be observed and even palpated. Sublingual tissues should be examined or abnormalities or foreign bodies. Inflammation of the tongue or glossitis can be present due to viral infections, immune-mediated problems such as LPS or auto-immune, and toxicity from irritative substances or objects. Lesions of unknown origin should be biopsied for further diagnostic workup.

Squamous Cell Carcinoma is the most common malignancy in the oral cavity of cats followed by fibrosarcoma and melanosarcoma. In dogs, the three most common tumors are melonomas, fibrosarcomas and squamous cell carcinomas. The only way to confirm diagnosis is by biopsy.

0ronasal fistulas (ONF):

In maxillary teeth, the width of the alveolar bone between the teeth and nasal cavity or sinus can often be very thin, especially in long, narrow-nosed dogs such as dachshunds. These fistulas can go undetected because they are most commonly located on the palatal surface of the canines. Oronasal fistulas require surgical repair.

Previous dental treatments such as; restorative, pulp capping, root canals and orthodontic appliances should documented as well as procedures performed the day of the charting such as open or closed root planing.

The importance of radiographs is another lecture, however is it necessary to document problems found on these x-rays. Bone loss, retained root tips and periapical lesions are just a few. These lesions can lead to draining tracts and oronasal fistulas. These fistulas are tracts that are formed by the infection and usually are visual externally by a wound on the muzzle below the eye.

The pathology listed in this text is some of the most common oral pathology you will encounter.

References

Logan, EI, Boyce EN: Oral Health Assessment in Dogs: Parameters and Methods. J. Vet Dent 11(2): 58-63.

Harvey, CE, Emily, PP: Periodontal Disease. In Harvey, CE, Emily, PP: Small Animal Dentistry. St. Louis:Mosby, 1993

Logan, EI, Finney, O, Hefferren, JJ: Effects of a Dental Food on Plaque Accumulations and Gingival Health in Dogs. J Vet Dent 19(1), 15-18.

Holmstrom, SE: Veterinary Dentistry for the Technician and Office Staff. W.B. Saunders Company, 2000

Gorrel, C: Veterinary Dentistry for the General Practitioner. Saunders, 2004

Lobprise, H: Clinical Companion, Five Minute Consult - Small Animal Dentistry, Blackwell, 2007.