Selected Dental Anomalies and Procedures

Occlusal Defects..
Other Congenital Anomalies.
Acquired Problems
Oral Masses
Procedures

.

.

.

.

.

Occlusal Defects:

Brachygnathism (Overbite): the upper jaw is longer than the lower jaw. This is a genetic-base "defect", and can affect any breed

Prognathism (Underbite): the lower jaw is longer than the upper jaw due to a genetic determinant. This is the "desired" arrangements in certain breeds, e.g Boxer, Pekinese, Bulldog, Llaso Apso

Wry Mouth: describes a situation in which one half (left or right) of the mouth/bite is brachygnathic or prognathic.







Supernumerary Teeth: this is a problem in which extra permanent teeth appear in young dogs. Usually, a problem in the upper jaw...but not always. The extra teeth are seen either behind the normal position...or in the normal arcade, causing crowding and often resulting in malocclusion





Other Anomalies:

Split Tooth and Twin Crowns:
During the development of the tooth, the tooth bud (the origin of a tooth) either splits OR two tooth buds fuse. This is eventualy manifest as either two separate crowns (on one large tooth) sharing a common root system OR...if a split tooth occurs, two separate root systems sharing a common crown. It can be seen in deciduous ("baby") teeth and permanent teeth...mostly occuring in incisors. It can cause crowding and malocclusion.










Retained Deciduous Teeth:
Occurs when deciduous ("baby") teeth are not resorbed with eruption of permanent teeth. Because retension of these teeth causes crowding, these can interfere with normal development and positioning of permanent teeth.












Enamel Hypoplasia/Defect:
Viral, chemical or other causes of defective tooth development or trauma may result in the absence of adequate enamel over the crown. The underlying dentin is easily stained and and affected teeth are easily broken or worn. The problem may be focal ("Enamel Defect"...one area) or generalized (more or less everywhere). Focal lesions/defects (as apposed to generalized ) can often be repaired. More information about restoration is shown below, in Selected Dental Procedures









Acquired Problems
























Calculus-Plaque
Plaque is the result of food debris, bacterial action on this material in the presence of saliva...with the product being deposited on irregular surfaces of teeth. When plaque is not removed on a regular basis, it becomes mineralized....forming calculus.









Gingival Hyperplasia:
This problem is believed to be genetic in origin, though it is plausible that chronic gingivitis may give rise to it.It is described as exhuberant accumulation of gingival tissue, sometimes covering the crowns of adjacent teeth. In the presence of gingival hyperplasia, periodonal disease may ensue, due to the presence of "pseudopockets" formed by gingiva surrounding teeth. Breeds most commonly affected are Collies and Boxers. Treatment is repeated surgical reduction.















Periodontal Disease:

Often periodontal disease evolves as a sequelae to plaque, tartar and calculus buildup. When saliva contacts a tooth, a glycoprotein layer is laid down permitting certain oral bacteria to adhere to the surface of the tooth. These bacteria synthesize other polysaccharides that permit other bacterial species to also adhere to the surface of the tooth, forming "plaque. The entrapment of bacteria and bacterial toxins in plaque, facilitated by the presence of food, as well as the physical interaction of developing calculus (hard/irritating) stimulates an inflammatory response by the juxtapositioned gums (gingiva) including the tooth's surrounding gingival "pocket". Plaque extends under gums causing inflammation there, and this, in turn loosens the periodontal ligaments' attachment to alveolar bone, resulting in deeping of the pocket and recession of gingival tissue, which results in partial root exposure, and invites furthur advancement of tartar and calculus to these areas. As periodontal ligaments are damaged, and gingiva recede, affected teeth loosen and are painful. The animal may drool, gag, wretch and cough. Halitosis is common. Abscessation of surrounding pocket or root apices involving adjacent bone can lead to bone infection (osteomyelitis),oronasal fistula and systemic infection
Periodontal disease may arise from primary metabolic, neoplastic and infectious diseases and gingival hyperplasia, as well. Examples of metabolic diseases causing periodontal disease are Hypothyroidism and Cushings Disease, Diabetes .There may be others.













Oronasal Fistula:
This is a hole allowing direct communication of the oral and nasal cavities. Foodstuff may pass directly into the fistulous orifice, dwelling in the nasal cavity, causing sneezing and representing a basis for an additional infection nidus. Often the cause is a tooth abscess with secondary drainage of prurulent material into the nasal cavity.













Tooth Abscess:

An abscess is a focal accumulation of prurulent material (aka "pus"). The most common cause is advances periodontal disease. The large periodontal pocket permits accumulation of bacteria and food to collect. Growth of bacteria and inflammation from calculus and tartar forces the accumulation of purulent material. The resulting loosening of periodonal ligament leads to advancing inflammation and movement of teeth which are no longer firmly anchored in place. Affected animals are painful, reluctant to eat, may rub the face with paws and may drool with blood tinged material visible. Sneezing may occur if there is sufficient drainage into the nasal cavity. Diagnosis is made via presence of advanced periodontal disease, loose teeth and radiographic confirmation (increased lucency around root, and recession/loss of alveolar bone from the neck of the tooth).

Trauma is another potential cause of tooth abscess via infection of and extension from exposed pulp. A tooth root abscess of the upper canine tooth can lead to drainage of the prurulent exudate into a nasal sinus and nasal cavity. Typically, a swelling is present below the eye on the affected side. Sometimes, there is rupture from here back into the oral cavity, creating an oronasal fistula.Sneezing is common.

Treatment of abscessed teeth requires extraction.










Exposed Pulp Cavity


Undue wear from chewing abrasive material (e.g. tennis balls, rope, stones, constant chewing of fur) may result in exposure of tooth pulp. When the process occurs gradually, reparative dentin in created which protects the pulp from environmental contacts and infection. A brown spot is seen at the area of wear, but a dental probe is unable to penetrate into pulp due to overlying dentin. If, on the other hand, the process occurs rapidly, exceeding the rate of dentin formation, there is communication between pulp and environment and endodontic intervention is required to protect the integrity of the tooth.










CUPS (Chronic Ulcerative Paradental Stomatitis)

This disease is also known as idiopathic stomatitis, ulcerative stomatitis or lymphocytic-plasmacytic stomatitis and occurs in any breed though Maltese and King Charles Cavalier Spaniels seem predisposed. This is an immune-mediated disease in which the animal develops an allergic reaction to bacterial plaque on the teeth. Buccal (i.e. cheek) and lingual (i.e. tongue) tissue resting against affected teeth develop red, raised and often ulcerated lesions that are painful. Affected animals are often inappetant, develop severe, fetid halitosis, drool (with resulting secondary dermatitis of the lips); enlarged submandibular lymph nodes are sometimes seen. Diagnosis is via tissue biopsy and treatments vary depending on the severity of the signs. Fastidious, long-term oral care, anti-inflammatory or immuno-suppressive therapy and antibiotics are commonly employed. In many animals, the disease is never resolved and teeth...even relatively healthy teeth...must be extracted.









Oral Masses










Epulides

These growths are found mostly in older dogs...especially boxers...and are usually associated with the fourth premolar (carnaissal teeth) and canine teeth.
Epulides arise from periodontal ligamental tissue.
There are three basic types:  Fibromatous, Ossifying and Acanthomatous. The ossifying and acanthomatous varieties can be locally invasive. They may be smooth or ulcerated, firm, tightly adhered or pedunculated (hanging via a neck portion) to underlying tissue..

An acanthomatous epulis behaves as locally bone-invasive malignancy. It assumes a yellow-pink to reddish coloration and texture similar to some squamous cell carcinomas. These growths do not metastasize and are amenable to surgical removal and radiation treatment (preferred to lessen the liklihood of recurrence). There is, however, about a 20% chance that treated lesions will reappear as full-fledged malignancies months to years later.

Fibromatous and osseous (ossifying) epulides are histologically similar, differing only in the mount of bone matrix that is present. These are most commonly seen on the forward-most portions of the gingiva (gums), may or may not be pigmented and primarily are found in medium to large breed dogs. In some respects, fibrous epulides are macroscopically and microscopically similar to gingival hyperplasia; an occasional lesion may grossly resemble a fibrosarcoma, a true oral malignancy. Surgical treatment, if deemed necessary (because lesions are interfering with normal function) is generally rewarding.

Papilloma

These are viral (papova virus) in origin and multiple raised, white to tan, smooth to irregular growths may appear on the cheeks, palate, throat, and on occasion, the lips. These are primary a problem in young dogs, and they are very contagious. Animals may drool, with or without blood, and have difficulty eating. These often regress spontaneously but sometimes surgery is indicated when the animal is experiencing the above problems.



Neoplasias

The most common oral neoplasias (excluding the epulis class) are malignant melonoma and squamous cell carcinoma. Fibrosarcomas and papillomas are occasionally present, as well.










Malignant melanomas

constitute about 30%-40% of oral neoplasms in dogs. The most common site is the cheek (buccal mucosa) and invasion to underlying bone is common (greater than 50% of cases). There is a high probability of metastasis (spreading to other tissues in the body).






Non-tonsillar squamous cell carcinoma

causes about 20%-30% of oral neoplasias in dogs...usually found on gingiva and tooth sockets (alveoli). Again there is high liklihood of invasion to underlying bone (greater than 75% of cases) but metastasis is slow, appearing very late in the disease.






Fibrosarcoma

This fibrous tumor is most often manifest in the upper jaw and dental margins, palate and into nasal cartilage. Grossly, it may resemble a fibromatous epulis. Sometimes these are ulcerated and blood is seen in the mouth.These tumors tend to be locally aggressive, almost always invading underlying bone (making surgical resection difficult). Rarely there is metastasis to the lungs (they are much less likely to metastasize than the other most common oral malignancies). Fibosarcomas are most often seen in two breed-age populations: In small dogs, greater than 8 yrs old and in large dogs around 4-5 yrs old. Treatment is surgical resection followed by radiation or hyperthermia-enhanced radiation. Survival for one year after aggressive treatment is about 6 months; a few animals may survive one year. 









Oral Osteosarcoma
Osteosarcomas are neoplasias of bone tissue. Most osteosarcomas are of the appendicular variety...affecting bones of limbs. However, occasionally bone neoplasia of this type affects the jaws.











Procedures

Calculus and Periodontal Therapy

Hand instruments include Peridontal Probe: to measure depth of periodontal pockets, Dental Explorer: to detect irregularities on the tooth's surface; Straight Extraction Forceps or Rongeurs to remove tooth calculus; Supragingival Scaler, also to remove tooth tartar and calculus; Subgingival Curette: to remove subgingival deposits and restore smooth root surface. Most tartar and mild calculus is readily removed with ultrasonic or sonic scaler instruments










Instruments for Extraction

Periosteal Elevator, Luxator, Coupland's Bone Chisel, Lind-Levian Elevator and Root Tip Pick and extractors are used for extracting diseased or supernumerary teeth. In general, root elevators are employed to break down the periodontal ligament fibers attachments around the circumferance of the root. Then, when the root is sufficiently loose, the crown is grabbed with an extractor to facilitate lifting the tooth via a few twisting and pulling motions. It is important to completely loosen the periodontal attachments prior to twistinig/pulling with an extractor or portions of the root may be broken and left in place.

Alternatively, in some instances it is more expeditious to approach the root via removal of the overlying bone; this facilitates better exposure of root attachments and lessens likelihood of inadvertently breaking of a piece of the root.








Scaling

Gross calculus can removed with extraction forceps; residual calculus can be removed with a hand (supragingival scaler); calculus above the gingival line can be removed with the a sickle-shaped scaler gently pushing the gingiva up and away from the tooth in the process.

Most scale and tartar associated with the tooth's crown is easily dislodged with a ultrasonic scaler or sonic scaler.








Root Planing

Whereas subgingival scaling involved removal of tartar and calculus from below the surface of the gingival margin, root planing is the removal of superficial layer of toxin-laden cementum from the root surface. The result is a smooth root that resists accumulation of toxins and is more receptive to reattachment. A subgingival curette is used for both subgingival scaling and root planing.







Ultrasonic Scaler

(See also Sonic Scalers, below)

There are two types: The magnetostrictive and the piezoelectric.

The magnetostrictive ultrasonic device utilizes high frequency electrical current through a coil in the handpiece to alternatively magnetize-demagnetize a ferromagnetic rod within the handpiece. This leads to vibration of the ferromagnetic stack when current is applied. This, in turn, is connected by a rigid tip to a rod and the tip is made to oscillate in an elliptical pattern. The tip is cololed via a stream of water.

Piezoelectric scalers pass high-frequency electric currents to a piezoelectric crystal which changes shape with the oscillating current...vibrating in a semi-elliptical manner. Like the magnetostrictive variety, the tip is cooled via water. These instruments still generate significant heat and are not recommended for subgingival scaling due to potential for heat-induced soft-tissue damage.

Sonic Scaler

These are handpieces attached to an air-driven dental unit. The tip oscillates relatively (compared to ultrasonic devices) slowly (less than 20 kHtz).Sonic scalers generates less heat then the ultrasonic devices but it they are also less powerful. However, they can be safely used for subgingival scaling.





Orthodonture

Orthodontic procedures, not quite as common in general practice settings as the other procedures discussed in this section, are nevertheless, employed by many veterinarians and veterinary dentists to correct occlusive problems, that can not be corrected via tooth extraction methods (or if extraction is deemed to be unacceptable for any reason). Various appliances, crowns, bridges, etc are readily employed where appropriate.