Chapter 64 Dentistry and Diseases of the Oropharynx
Dental disease and diseases of the oropharynx are common in dogs and cats. These diseases can be divided into categories including oral surgical disease, periodontal disease, endodontic disease, orthodontic disease, stomatitis/gingivitis, neoplastic disease, and salivary gland disease. Neoplastic disease of the maxilla and mandible is discussed in Chapter 99.
ORAL SURGICAL DISEASE
The two major categories of oral surgical (nonneoplastic) disease are:
Anatomy
• The dentition, including root structure, of dogs and cats is illustrated in Figures 64-1 and 64-2, respectively. Tooth roots for both species are listed in Table 64-2.
• Basic anatomic structures of the teeth and related areas are illustrated in Figure 64-3 and defined in Table 64-3.
Table 64-2 TOOTH ROOTS IN DOGS AND CATS
| Type of Tooth | No. of Roots |
|---|---|
| In Dogs | |
| Incisor | 1 |
| Canine | 1 |
| Maxillary (upper) cheek teeth: | |
| 1st (1st P) | 1 |
| 2nd and 3rd (2nd and 3rd P) | 2 |
| 4th–6th (4th P; 1st and 2nd M) | 3 |
| Mandibular (lower) cheek teeth: | |
| 1st and last (1st P; 3rd M) | 1 |
| 2nd–6th (2nd–4th P; 1st and 2nd M) | 2 |
| In Cats | |
| Incisor | 1 |
| Canine | 1 |
| Maxillary (upper) cheek teeth: | |
| 1st (2nd P) | 1 |
| 3rd (4th P) | 3 |
| All others | 2 |
| Mandibular (lower) cheek teeth: | |
| All | 2 |
M, molar; P, premolar.
Table 64-3 BASIC ANATOMIC STRUCTURES OF THE DENTITION
| Crown: | Portion of the tooth located in the oral cavity. It is covered by enamel. |
| Root: | Portion of the tooth that lies within the alveolar bone. It is covered by cementum. |
| Furcation: | The space between the roots of a multirooted tooth. |
| Periodontal ligament: | Ligament that attaches the root of the tooth to the alveolar bone. |
| Interradicular bone: | Bone located between the roots. |
| Buccal bone: | Bone located on the buccal, or cheek, side of the tooth root. |
| Attached gingiva: | Keratinized gingiva firmly attached to the underlying alveolar bone. |
| Alveolar mucosa: | Mucosa that is loosely attached to the underlying bone. |
| Mucogingival line: | Anatomic landmark that separates the attached gingiva from the alveolar mucosa. |
Diseases Requiring Dental Extraction
Diagnosis and Indications for Extraction
The decision to perform dental extraction depends not only on the dental disease present but also on the client’s ability and desire to pursue alternatives to extraction, such as periodontal, endodontic, and orthodontic therapy.
Gross Decay/Dental Erosion
• In dogs, gross decay, which usually occurs on the occlusal or biting surface of the maxillary first molar, and less frequently on the distal cusp of the mandibular first molar, can be identified with a dental explorer placed into the soft carious lesion. Penetration of the explorer into the soft demineralized enamel/dentin confirms gross decay. Radiographs of the affected tooth will show the extent of the lesion.
• Odontoclastic resorptive lesions are very common in cats. These defects are referred to as feline odontoclastic resorptive lesions (FORLs).
• FORLs often are extensive and painful and usually are covered by granulation tissue. Removal of the granulation tissue reveals the underlying erosive lesion.
• Determine the extent of the resorptive lesion in the region of the cementoenamel junction and crown of the tooth with a dental explorer.
Periapical Inflammation
• Carefully examine teeth in the area of acute facial swelling for deep periodontal pockets with a periodontal probe and for pulpal exposure with a dental explorer.
• Periapical lysis will be present around the apex of the affected root. Radiographs can confirm the diagnosis.
Impacted Teeth
Impacted (unerupted) teeth may cause nasal discharge, orthodontic problems, and bone loss.
• Dentigerous cysts may occur and can cause expansion of bone with subsequent facial asymmetry, extreme displacement of teeth, severe root resorption of adjacent teeth, and bone loss.
Deformed Teeth
• Diagnose minor dental deformities such as enamel hypoplasia based on the observation of symmetric defects and staining of enamel combined with a history of illness during tooth development. No treatment is required in most cases.
Preoperative Considerations
• Before performing dental extractions, perform a thorough physical examination, standard laboratory tests including a complete blood count (CBC), serum biochemistry, and urinalysis.
• Perform appropriate radiographic procedures, based on the animal’s clinical signs, physical examination findings, and age.
Surgical Procedure
Equipment
Table 64-4 DENTAL EQUIPMENT APPLICATIONS
| Equipment | Applications |
|---|---|
| Portable electric dental drill with low-speed hand piece and prophy angle (Vetroson Millennium Motor Pack, Henry Schein, Inc.; Port Washington, NY) | Sectioning teeth, removal of alveolar bone, polishing teeth |
| Mobile delivery system with high-speed handpiece, low-speed handpiece, water and air syringe (Vet-Base, Henry Schein, Inc.) | Sectioning teeth, removal of alveolar bone, polishing teeth, cavity and crown preparations |
| Piezoelectric scaler, electric or air driven (Spartan USA, Inc.; Fenton, MO) | Permits rapid, easy removal of dental calculus |
| Dental radiography unit (AFP Imaging, Elmsford, NY) | Permits rapid, easy exposure of dental radiographs |
Table 64-5 DENTAL INSTRUMENTATION
| Instrumentation* | Applications |
|---|---|
| Oral Surgery | |
| Dental elevator | Tears periodontal ligament during extraction |
| Dental luxators | Has a thinner, sharper blade than traditional elevators |
| Extraction forceps | Completes breakdown of periodontal ligament and removal of tooth from alveolus during extraction |
| Root tip pick | Removal of small-breed deciduous teeth or broken root tips |
| Bone curette | Debridement of alveolus following extraction |
| Periosteal elevator | Elevation of mucoperiosteum during oronasal fistula repair and palatal surgery |
| Periodontic | |
| Periodontal probe/explorer | Measurement of depth of periodontal pocket (probe); detection of pulpal exposures and carious lesions (explorer) |
| Hand scalers | Subgingival scaling |
| Curette (Columbia #13/14) | Removal of accretions on the root surface and removal of granulation tissue from the pocket wall |
| Prophylaxis paste | Polishing teeth following scaling |
| Endodontic | |
| Endodontic files (Hedstrom/K-Files) | Debridement of necrotic pulpal tissue from canal |
| Root canal plugger | Compression of gutta percha into the apex |
| Light-Speed and SimpliFil System† | |
* Available from Henry Schein, Inc.; Port Washington, NY and from Cislak Manufacturing Inc, Niles, IL.
† Available from Light Speed Endodontics, San Antonio, TX.
| Material | Applications |
|---|---|
| Composite resins (Prodigy, sdsKerr, Orange, CA) | Aesthetic restorations following endodontic therapy or cavity preparation |
| Glass ionomers (Vitrebond, 3M EPSE, St. Paul, MN) | Restoration of feline external root resorptive lesions |
| Endodontic sealers (AH Plus, Dentsply, Konstanz, Germany) | Endodontic filling material |
| Mineral trioxide aggregate (ProRoot MTA, Dentsply Tulsa Dental, Tulsa, OK) | Stimulates closure of an apex and reparative dentin formation following spulpotomies |
| Gutta percha (Successfil, Hygenic) | Fills the pulp canal following debridement during root canal therapy |
Simple Extraction
Simple extraction refers to the extraction of a small single-rooted tooth such as an incisor.
Technique
1. Place an appropriate-size dental elevator in the periodontal ligament to sever the attachments of the gingiva around the tooth.
2. Advance the elevator apically (toward the apex or tip of the root) between the alveolar bone and root.
3. Rotate the elevator and hold for 15-second intervals to tear the periodontal ligament (Fig. 64-4A).
5. When the tooth is loose, place an appropriate-size dental extraction forcep on the crown near the gingival margin and rotate and remove the tooth from the alveolus (Fig. 64-4B).
Multirooted Extraction
Complicated Surgical Extraction
Technique
2. Retract the gingival and protect it with the end of a small flat feline periosteal elevator while the crown is amputated with a #3 round bur on a high-speed handpiece at or slightly apical to the level of the alveolar crest (Fig. 64-7B).
3. Check the crown amputation with a dental explorer and remove any residual crown or sharp bony projection with the bur (Fig. 64-7C).
4. Flush the site with sterile saline, replace the flap, and close with simple interrupted absorbable sutures (Fig 64-7D).
Postoperative Care and Complications
• Administer a broad-spectrum antibiotic (e.g., amoxicillin clavulanate) for 3 to 7 days when infection is present.
Broken Root Tips
• Differentiate broken root tips from surrounding alveolar bone by the following features:
• Remove root tips with a root tip pick or obliterate with an appropriate-size round bur (Fig. 64-8). Removal with a root tip pick is preferred because obliteration of roots with a bur may cause damage to underlying structures.
Oronasal Fistulas and Palatal Defects
Anatomy
The surgical anatomy varies with the location of the defect. The mucoperiosteal flap used in the repair of oronasal fistulas extends from the margins of the defect across the mucogingival line (the anatomic landmark separating the attached gingiva from the alveolar mucosa). Surgical techniques used to repair defects in the hard palate often require preservation of the palatine arteries, which arise approximately 1 cm palatal to the maxillary fourth premolar and course rostrally along the hard palate (Fig. 64-9).
Etiology
Palatal defects may be congenital or acquired.
Acquired Defects
• Acquired palatal defects are most frequently caused by a deep maxillary periodontal pocket that has progressed toward the apex of the tooth, resulting in lysis of the thin layer of bone that separates the palatal aspect of the root of the maxillary tooth and the nasal cavity.
• Acquired palatal defects that have etiologies other than dental disease usually are located in the hard palate and may be caused by various types of trauma including dog bites, blunt head trauma, electrical shock, gunshot wounds, foreign body penetration, and pressure necrosis. They also may occur as a complication of maxillectomy for oral neoplasia.
Clinical Signs
• Clinical signs associated with oronasal fistulas and palatal defects include unilateral or bilateral mucopurulent and occasionally hemorrhagic nasal discharge.
Diagnosis
• Perform a thorough periodontal examination to identify oronasal and oroantral fistulas secondary to periodontal disease. This requires tranquilization or general anesthesia.
• Insert a periodontal probe into the suspected periodontal pocket, which often is located on the palatal aspect of the maxillary canine tooth but may be located anywhere along the periodontal ligament of the maxillary cheek teeth.
Preoperative Considerations
• Perform surgery when the animal is 3 to 4 months of age following thoracic radiography to check for pneumonia.
Surgical Procedure
Single-Layer Mucoperiosteal Flap
Technique
3. Make two divergent incisions in the mucosa, beginning at the mesial and distal aspects of the fistula and extending across the mucogingival line (Fig. 64-10A).
5. Reflect the flap apically and incise the deepest layer of the flap (the periosteal layer) the entire width of the flap at its most dorsal aspect (Fig. 64-10C).
6. If necessary, remove excess buccal bony plate and sharp edges of bone with a rongeur or dental bur to permit tensionless apposition of tissues (Fig. 64-10D).
7. Before closure, remove all debris and granulomatous tissue with a bone curette, and irrigate the surgical site with sterile saline.
8. Suture the flap to the palatal and gingival mucosa with 3-0 or 4-0 poliglecaprone (Monocryl) in a simple interrupted pattern (Fig. 64-10E).
Double-Layer Mucoperiosteal Flap
Technique
1. Remove the mesial, distal, and buccal epithelial margins of the fistula with a #15 blade. Do not remove the palatal epithelial margin.
2. Elevate an elliptical palatal mucoperiosteal flap with a periosteal elevator, preserving the lateral attachment of the base of the flap (Fig. 64-11A).
3. Fold over and suture the flap to the periosteum of the edge of the defect with 3-0 or 4-0 poliglecaprone (Monocryl) in a simple interrupted pattern (Fig. 64-11B).
4. Elevate a buccal mucoperiosteal flap from the lateral aspect of the oronasal fistula (see Fig. 64-10C).
5. Advance the buccal mucoperiosteal flap palatally to cover the inverted flap and the denuded palatine bone (Fig. 64-11C).
6. Suture the flap to the palatal and gingival mucosa with 3-0 or 4-0 poliglecaprone (Monocryl) in a simple interrupted pattern (Fig. 64-11D).
Overlapping Flap Technique
Technique
1. Make an incision the length of the palatal defect in the palatal mucosa just palatal to the maxillary dental arcade. The rostral and caudal aspects of these incisions are connected to the rostral and caudal aspects of the hard palatal defect (Fig. 64-12A).
2. Incise the opposite side of the palatal defect along the entire length of the defect and gently elevate with a periosteal elevator to create a recipient site for the mucoperiosteal flap. Carefully elevate the mucoperiosteal flap with a periosteal elevator, preserving the palatine artery (see Fig. 64-9) that arises approximately 1 cm palatal to the upper fourth premolar (Fig. 64-12B).
3. Hinge the mucoperiosteal flap at the end of the palatal defect and place beneath the mucosa on the other side of the defect.
4. Preplace 3-0 PDS (polydioxanone) sutures in an interrupted vest-over-pants suture pattern through the recipient site and the flap.
6. Make an incision along the edges of the soft palatal defect and close in two layers by apposing nasal mucosa to nasal mucosa with the knots in the nasopharynx and oral mucosa to oral mucosa with the knots in the oral cavity.
Postoperative Care and Complications
• Feed a soft diet (gruel or liquid) for 2 to 3 weeks. For animals requiring complicated repair, consider using esophagostomy or gastrostomy tube feeding (see Chapter 3). Place Elizabethan collars on patients that paw at the oral cavity.
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