Canine and Feline Dentistry PDF

Dentistry 4 CH A P TE R Sandra Manfra Marretta and Rebecca S. McConnico CA...

Dentistry 4 CH A P TE R Sandra Manfra Marretta and Rebecca S. McConnico CANINE AND FELINE DENTISTRY Dental Anatomic Review I. Dental formulas Deciduous Dentition Permanent Dentition Dog 2 (I3/3, C1/1, P3/P3)  28 teeth 2 (I3/3, C1/1, P4/P4, M2/M3)  42 teeth Cat 2 (I3/3, C1/1, P3/P2)  26 teeth 2 (I3/I3, C1/C1, P3/P2, M1/M1)  30 teeth A. Incisor teeth: There are three incisor teeth in each II. Adult root structure quadrant in dogs and cats, the 1st, 2nd, and 3rd A. Dogs: All incisor and canine teeth have one root. incisors. These teeth are used for cutting and The first maxillary cheek tooth (1st premolar) grooming has one root, the next two (2nd and 3rd premo- B. Canine teeth: There are a total of four canine lars) have two roots, and the next three (4th pre- teeth in the dog and cat. These teeth are used for molar, 1st molar, and 2nd molar) have three puncturing and tearing roots. The mandibular cheek teeth in the dog all C. Cheek teeth: The cheek teeth are located behind have two roots except the first and last cheek the canine teeth and are divided into premolars teeth, which have one root and molars. Premolars are used for shearing, mo- B. Cats: All incisor and canine teeth have one root. lars for crushing The first maxillary cheek tooth (2nd premolar) 1. Premolars: Adult dogs have four maxillary pre- has one root, the next tooth (3rd premolar) has molars and four mandibular premolars on each two roots, and the next tooth (4th premolar) has side. The 1st maxillary premolars are not pres- three roots. The small maxillary 1st molar in the ent in the cat, and the 1st and 2nd mandibular cat has two small roots. The mandibular cheek premolars are not present in the cat. The max- teeth (3rd and 4th premolars and 1st molar) in illary premolars are the 2nd, 3rd, and 4th pre- cats all have two roots molars in the cat. The mandibular premolars in III. Gross anatomy of the tooth and surrounding bone the cat are the 3rd and 4th premolars (Figure 4-1) 2. Molars: There are two maxillary molars on A. Crown: Portion of tooth that is normally visible in each side in the dog, the 1st and 2nd maxillary the mouth molars. In the cat there is only one very small B. Root: Portion of tooth that is imbedded in the maxillary molar on each side, the 1st maxillary bone of the maxilla or mandible molar. There are three mandibular molars on C. Enamel: Hardest substance in the body that cov- each side in the dog, the 1st, 2nd, and 3rd mo- ers the outer layer of the crown lars. In the cat there is one mandibular molar D. Dentin: Intermediate layer of the tooth and forms on each side, the 1st molar. the bulk of the calcified tooth structure 3. Carnassial teeth: The largest maxillary cheek E. Pulp: Innermost layer of the tooth and consists of teeth in the dog and cat are the maxillary 4th nervous, vascular, and loose connective tissue premolars. The largest mandibular cheek teeth F. Cementum: Covers the outer layer of the root of in the dog and cat are the mandibular 1st mo- the tooth lars. An easy way to remember the proper G. Cemento-enamel junction: Separates the crown identification of the cheek teeth in the dog from the root and separates the portion of the and cat is to remember that the largest cheek tooth covered by either enamel or cementum tooth in the maxilla is the 4th premolar H. Furcation: The point at which the roots of a multi- and the largest cheek tooth in the mandible rooted tooth branch from the crown is the 1st molar and count rostrally or I. Apex: Tip of the root of a tooth through which mesially. blood vessels and nerves enter the tooth 31 32 SECTION I GENERAL DISCIPLINES IN VETERINARY MEDICINE Dentin Crown Pulp Root Periodontal ligament Furcation Interradicular bone A Alveolar mucosa Mucogingival line Attached gingiva B Figure 4-1 A, Anatomy of the tooth. B, Gingival anatomy. (From Birchard SJ, Sherding RG. Saunders Manual of Small Animal Clinical Practice, 3rd ed. St Louis, 2006, Saunders.) J. Gingival sulcus: Normal space between the edge B. Stages of periodontal disease and diagnostic of the gingival margin and the attachment of the evaluation tooth (normal depth of the gingival sulcus is no 1. Stage I (gingivitis): Gingiva is inflamed but more than 1 to 3 mm in depth in dogs and 0.5 to there is no attachment loss 1 mm in cats) 2. Stage II (early periodontal disease): Periodon- K. Periodontal ligament: Collagenous fibrous bun- tal probing and dental radiographs may indi- dles that attach the cementum of the root of the cate attachment loss of up to 25%, with the tooth to the alveolar bone (radiographically the teeth remaining stable periodontal ligament appears as a radiolucent 3. Stage III (moderate periodontal disease): Peri- [black] line around the roots of teeth) odontal probing and dental radiographs may IV. Tooth type. Brachyodont: Short crown-root ratio indicate attachment loss between 25% and 50% with a true root; once apex forms, tooth growth of the root length, and teeth may begin to be- stops come mobile 4. Stage IV (severe periodontal disease): Peri- odontal probing and dental radiographs may Common Dental Diseases in Dogs and Cats indicate attachment loss greater than 50%, and I. Periodontal disease there is severe loss of supporting tooth struc- A. Pathophysiology: Most common disease diag- tures and teeth become loose nosed in dogs and very common disease in cats. C. Clinical presentations of periodontal disease Periodontal disease increases significantly with 1. Common clinical presentations of periodontal increasing age and is more severe in small-breed disease: Mobile teeth, periodontal and periapi- dogs. Periodontal disease is caused by an accu- cal abscesses with secondary facial swelling, mulation of bacteria in the form of plaque on the gingival recession, mild to moderate gingival surface of the teeth, which causes inflammation hemorrhage, and deep periodontal pockets of the surrounding tissues. As periodontal with secondary oronasal fistula formation with disease progresses, the periodontal ligament secondary chronic rhinitis that attaches the root of the tooth to the alveolar 2. Uncommon clinical presentations of periodon- bone is destroyed and attachment of the tooth tal disease: Severe gingival sulcus hemorrhage, to the bone is lost, the gingiva recedes, the furca- pathologic mandibular fractures, painful tion of multirooted teeth are exposed, and ulti- contact mucosal ulcers, intranasal tooth mately the attachment of the tooth is severely migration, osteomyelitis, and ophthalmic compromised, which results in tooth loss problems  CHAPTER 4 Dentistry 33 D. Treatment and the pulp canal is more narrow and the 1. Dental charting with the patient anesthetized dentin is thicker and stronger, at which time a using a periodontal probe and dental radio- conventional root canal procedure may be per- graphs to assess attachment loss formed if necessary 2. Supragingival and subgingival scaling 2. Conventional endodontic therapy or nonsurgi- 3. Root planning and subgingival curettage cal root canal therapy: Most common form of 4. Polishing or irrigation endodontic therapy involving removal of the 5. Gingivectomy pulp tissue through the crown of the tooth and 6. Open-flap curettage with augmentation of placement of an inert material in pulp canal to bony defects prevent infection associated with necrotic pulp 7. Perioceutics 3. Surgical endodontic therapy: Rarely performed 8. Exodontia (extractions) endodontic therapy and involves conventional 9. Oronasal fistula repair endodontic therapy and amputation of the 10. Home care apex of the tooth with closure of the remaining II. Endodontic disease apical portion of the root A. Pathophysiology: Endodontic disease refers III. Feline tooth resorptive lesions to disease of the pulp of the tooth or the inner A. Pathophysiology: The cause of feline tooth re- aspect of the tooth that contains the blood ves- sorptive lesions is unknown; however, proposed sels and nerves of the tooth. The most common theoretical contributing factors in feline tooth re- cause of endodontic disease in small animals is sorption include excess vitamin D and excessive dental trauma. A series of events may occur in occlusal stress caused by eating large, dry kibble. some fractured teeth with exposed pulp, which Feline tooth resorptive lesions are caused by can result in significant clinical problems. This odontoclasts and can develop anywhere on the series of events includes pulpal exposure, bacte- root surface, not just close to the cementoenamel rial pulpitis, pulp necrosis, periapical granuloma, junction; resorption on the enamel as the initial periapical abscess, acute alveolar periodontitis, event is rarely observed. Resorptive lesions that osteomyelitis, and sepsis occur at the cementoenamel junction are filled B. Teeth most commonly fractured with highly vascular and inflamed granulation 1. Dogs: Canine teeth, incisors, and maxillary tissue. These lesions are often painful and bleed fourth premolars when probed with a dental explorer. Tooth re- 2. Cats: Canine teeth sorption in cats is frequently progressive, and the 3. Any tooth in a dog or cat may be fractured, resorptive lesions continue to enlarge until the although less frequently roots of affected teeth are completely resorbed or C. Stages, clinical signs, and evaluation of endodon- the crown of the tooth breaks off, leaving behind tic disease remnants of resorbing roots 1. Acute pulpal exposure (acute endodontic dis- B. Teeth affected by feline tooth resorptive lesions: ease): Animals may hypersalivate, they may be All types of teeth may be affected, but the man- reluctant to eat, and the tooth will bleed at the dibular 3rd premolars are the most frequently af- site of the pulpal exposure. A dental explorer fected teeth under anesthesia can be inserted into the pulp C. Clinical signs and evaluation of feline tooth re- canal and the pulp will bleed sorptive lesions 2. Chronic pulpal exposure: Facial swelling, 1. Resorptive lesions are often painful when the sneezing, nasal discharge, or mucosal or cuta- lesion involves the crown neous fistulas. A dental explorer under anes- 2. Lesions may be hidden from view by plaque, thesia can be inserted into the pulp canal, but dental calculus, or inflamed gingival tissue the pulp is necrotic and will not bleed 3. Dental explorer used to localize lesions: when D. Radiographic changes associated with chronic explorer encounters a resorptive lesion, it will endodontic disease fall into the irregular area of resorption 1. Periapical lysis (radiolucency around apex or 4. Dental radiographs necessary to determine the dark halo around root tip) full extent of the resorptive process and to de- 2. Apical lysis (radiographic loss of the apex) termine the appropriate treatment plan 3. Large endodontic canals compared with con- D. Treatment options tralateral tooth (when teeth are affected with 1. Restoration: Lesions that extend into the den- endodontic disease when a dog is young, the tine but do not involve pulp tissue were previ- pulp remains large and dentin is not deposited ously restored; however, restoration of these in the tooth) teeth has been shown to be unsuccessful, so 4. Radiographic loss of tooth structure to pulp no longer recommended canal 2. Conservative management: Resorptive le- E. Treatment sions involving only the root and not the 1. Vital pulpotomy: Limited to very recent pulpal crown can be monitored both clinically and exposure in young dogs with very large pulp radiographically canals and is an attempt to maintain the viabil- 3. Whole tooth extraction: Ideal but often not ity of the pulp until at least the tooth is mature possible with advanced lesions 34 SECTION I GENERAL DISCIPLINES IN VETERINARY MEDICINE 4. Coronal amputation: Indicated when the crown C. Dental wear is affected and the root has been extensively 1. Attrition: Dental wear caused by tooth-to-tooth resorbed frictional contact IV. Feline gingivostomatitis 2. Abrasion: Dental wear caused by frictional con- A. Pathophysiology: The cause of feline gingivosto- tact of a tooth with a non-dental material matitis, also referred to as lymphoplasmacytic 3. Teeth respond to dental wear by laying down stomatitis or lymphocytic plasmacytic gingivitis tertiary or reparative dentin, which is visible stomatitis, is unknown; however, there may be an as a dark solid brown spot that cannot be immunologic basis for this condition and poten- entered with a dental explorer tial involvement of various viral agents 4. Very rapid dental wear may result in pulpal B. Oral pathologic findings: Severe inflammation may exposure that requires endodontic therapy or be focal or diffuse, including gingivitis, stomatitis, extraction and inflammation of the palatoglossal folds D. Enamel hypoplasia C. Diagnosis 1. Cause: A disruption of the ameloblasts during 1. Feline immunodeficiency virus (FIV) and FeLV the first several months of life while the teeth tests: Often negative are developing, which may be associated with 2. Complete blood cell count (CBC) and serum periods of high fever, infections (especially chemistry: Hypergammaglobulinemia canine distemper), nutritional deficiencies, 3. Histopathology: Submucosal inflammatory infil- disturbances in metabolism, systemic disor- trate of plasma cells, lymphocytes, macro- ders, and trauma phages, and neutrophils 2. Disturbance in enamel formation over a longer 4. Dental radiographs: To rule out resorptive le- period results in a more generalized distribution sions and bone loss secondary to periodontitis of lesions affecting multiple teeth in a bilaterally or oral tumors symmetrical manner while a solitary tooth that D. Treatment options is affected with enamel hypoplasia is most likely 1. Initial treatment: Periodontal therapy and the result of a focal traumatic episode home care with corticosteroid and antibiotic 3. Defective enamel is soft and porous, and the therapy as needed brittle enamel peels off exposing the underlying 2. Medical management alone often inadequate dentin, which is soon stained yellowish brown 3. In refractory cases, extraction of the teeth is 4. Treatment: Individual lesions can be restored; the treatment of choice (including all the pre- generalized lesions require diligent oral hy- molars and molars, and in some cases all the giene, fluoride treatment, and radiographic teeth may require extraction) monitoring for endodontic disease 4. Other treatment options: Laser thermoablation E. Dental caries combined with cyclosporine therapy if extrac- 1. Cause: Demineralization of calcified dental tion of teeth is not desired tissues when plaque bacteria use fermentable V. Miscellaneous small animal dental or oral diseases carbohydrates as a source of energy A. Normal occlusion and malocclusions 2. Dental caries are rare in dogs compared with 1. Normal scissors bite: The upper incisors are humans and have not been reported in cats; rostral to the lower incisors usually affect teeth with occlusal tables (molar 2. Undershot (mandibular prognathic bite): The teeth) mandible is longer than the upper jaw, and the 3. Early dental caries may appear as dark brown lower incisors are rostral to the upper incisors spots and have a sticky or slightly soft feel 3. Overshot (mandibular brachygnathic bite): when probed with a dental explorer The mandible is shorter than normal, and the 4. Following perforation of the enamel, dental upper incisors are significantly rostral to the caries progress rapidly in the dentin, resulting lower incisors in extensive loss of tooth structure with B. Abnormal number of teeth secondary pulpitis and pain and may 1. Persistent or overly retained deciduous teeth: result in pulp necrosis and periapical Common in small-breed dogs, and retained de- pathology ciduous teeth should be extracted as soon as 5. Treatment: Restoration or extraction of af- possible to help prevent the permanent teeth fected teeth from erupting in abnormal locations F. Lip-fold pyoderma 2. Abnormal number of teeth 1. Cause: Deep skin folds where the skin rubs a. Supernumerary teeth: Common in dogs and against itself, causing irritation resulting in a may be the result of either a genetic defect or pyoderma a disturbance during tooth development and 2. Skin folds create a moist, dark, and warm envi- require extraction if causing dental crowding ronment that supports the growth of bacteria b. Oligodontia: A rare congenital absence of or yeast and subsequent inflammation many but not all teeth 3. Dogs are often presented because of severe c. Hypodontia: Absence of only a few teeth is halitosis a relatively common genetic fault often in- 4. Breed predisposition: Cocker spaniel, springer volving missing premolar teeth spaniel, Saint Bernard  CHAPTER 4 Dentistry 35 5. Treatment: Medical management can include F. Facial abscess common in rabbits gentle exposure and cleansing of the skin fold 1. Cause: Secondary to periodontal or endodon- with an antiseptic shampoo, drying the area, tic disease and application of a mild astringent. Surgical 2. Diagnosis: Oral examination and dental radio- removal of the skin fold provides a more per- graphs manent solution 3. Treatment: Extraction of affected teeth with G. Craniomandibular osteopathy surgical debridement of abscess and local anti- 1. Cause unknown biotic therapy 2. Proliferative bone disease that results in the II. Rodents excessive deposition of periosteal new bone on A. Rodents: Guinea pig, chinchilla, rat, mouse, the base of the skull and caudal aspect of the gerbil, hamster mandible B. Dental formula: Varies with species from 16 to 3. Breed predisposition: Most frequently seen in 22 teeth West Highland white terriers and Scottish terri- C. Aradicular hypsodont incisors and either aradicu- ers but occasionally seen in other breeds lar hypsodont or brachyodont cheek teeth, de- 4. Signalment and presenting signs include the pending on species following: Young immature dogs with intermit- D. Clinical signs of dental disease similar to lago- tent fever, pain associated with attempting to morphs eat and pain when opening the mouth. If exces- E. Incisor overgrowth and cheek teeth overgrowth sive bone proliferation occurs, inability to similar to lagomorphs, depending on species open the mouth may be a complicating factor (Figure 4-2) 5. Once skeletal maturity is reached and the phy- ses close, bone proliferation decreases EQUINE DENTISTRY H. Masticatory muscle myositis 1. Cause: Immune-mediated disease affecting I. Dental formula: 2 (I3/3, C0-1/0-1, P3-4/3, M3/3)  36-42 muscles of mastication II. Tooth type: Hypsodont dentition (long reserve crowns 2. Breed predisposition: German shepherd dogs when young that shorten with age through attrition) and other adult large-breed dogs 3. Clinical presentation: Inability to open mouth with atrophy of muscles of mastication and se- vere temporal muscle atrophy 4. Diagnostics: Test for autoantibodies to type 2M myosin in muscle and serum and muscle bi- opsy demonstrates necrosis, phagocytosis, at- rophy with fibrosis 5. Treatment: Forceful opening of mouth under gen- eral anesthesia with aggressive immunosuppres- sive doses of steroids tapered over 6 months I. Common malignant oral tumors 1. Dogs: Melanoma, squamous cell carcinoma and fibrosarcoma 2. Cats: Squamous cell carcinoma (most common oral tumor in cats) Figure 4-2 Proper technique for dental trimming. (From Birchard SJ, Sherding RG. Saunders Manual of Small Animal Clinical Practice, 3rd ed. St Louis, 2006, Saunders.) LAGOMORPH AND RODENT DENTISTRY I. Lagomorphs A. Lagomorphs: Rabbits B. Dental formula: 2 (I2/1, C0/0, P3/2, M3/3)  28 C. All teeth are radicular hypsodont teeth (i.e., teeth that never form a true root with an apex and the tooth grows continuously throughout life D. Clinical signs of dental disease: Change in food preference, dropping food, anorexia, ocular or na- sal discharge, hypersalivation, persistent grinding of teeth, inadequate grooming E. Incisor overgrowth common in rabbits 1. Cause: Feeding diet with inadequate abrasive properties 2. Treatment: Correct cheek teeth overgrowth and extract or trim incisor teeth every 3 to 5 weeks Figure 4-3 Arabian horse, 2 years old. The deciduous incisors have small as needed and switch to more abrasive diet ridges and grooves on their labial surface. (From Baker G, Easley J. Equine (coarse hay) Dentistry, 2nd ed. Kidlington, UK, 2005, Saunders Ltd.)