NAVLE Gastrointestinal and Digestive

Feline Dental Diseases Study Guide

📅 March 28, 2026 ⏱ 25 min read

Dental diseases represent some of the most common conditions affecting domestic cats, with studies indicating that 50-90% of cats over 4 years of age have some form of dental pathology.

Overview and Clinical Importance

Dental diseases represent some of the most common conditions affecting domestic cats, with studies indicating that 50-90% of cats over 4 years of age have some form of dental pathology. The three most clinically significant feline dental diseases are tooth resorption (TR), periodontal disease, and feline chronic gingivostomatitis (FCGS). Understanding these conditions is essential for NAVLE success and clinical practice, as cats are masters at hiding oral pain.

Tooth resorption is particularly high-yield for the NAVLE, affecting 28-67% of cats depending on the population studied. The condition was previously known by various names including feline odontoclastic resorptive lesions (FORLs), cervical line lesions, and neck lesions. The current accepted terminology is simply tooth resorption (TR) as designated by the American Veterinary Dental College (AVDC).

Quadrant	Number	Location	Teeth Present
Right Maxillary	100	Upper Right	101-103, 104, 106-108, 109
Left Maxillary	200	Upper Left	201-203, 204, 206-208, 209
Left Mandibular	300	Lower Left	301-303, 304, 307-308, 309
Right Mandibular	400	Lower Right	401-403, 404, 407-408, 409

Feline Dental Anatomy

Adult cats have 30 permanent teeth with the dental formula: I 3/3, C 1/1, P 3/2, M 1/1 per side. Cats lack the first premolars (P1) in both jaws, and the mandible only has two premolars. The carnassial teeth (maxillary P4 and mandibular M1) are critical for shearing and are commonly affected by dental disease.

Modified Triadan System

The Modified Triadan System assigns a three-digit number to each tooth. The first digit indicates the quadrant (1=right maxillary, 2=left maxillary, 3=left mandibular, 4=right mandibular). The second and third digits indicate tooth position from rostral to caudal. Rule of Fours and Nines: The canine tooth is always 04, and the first molar is always 09.

High-YieldThe mandibular third premolar (307/407) is the most commonly affected tooth by tooth resorption and can be considered a sentinel tooth. If you find TR in this tooth, suspect other teeth are affected.

Finding	Description
Visual Appearance	Pink to red granulation tissue filling defect at or near gingival margin; often at cemento-enamel junction
Tactile (Explorer)	Hard, rough surface unlike smooth furcational bone loss; catches on sharp enamel ledge
Gingival Changes	Focal hyperplastic or hemorrhagic gingiva covering the lesion; bleeds easily when probed
Pain Response	Jaw chattering (pathognomonic) when lesion probed, even under general anesthesia

Tooth Resorption (TR)

Definition and Pathophysiology

Tooth resorption is a progressive, inflammatory condition characterized by odontoclastic destruction of dental hard tissues (enamel, dentin, and cementum). Odontoclasts are cells virtually identical to osteoclasts that become inappropriately activated and fail to down-regulate, resulting in continuous tooth destruction. The process typically begins on the root surface and extends coronally.

Etiology: The exact cause remains unknown despite extensive research. Proposed contributing factors include vitamin D excess, acidic diet, mechanical stress, and chronic inflammation. Unlike human dental caries, TR is NOT caused by bacteria and is not a true cavity.

Clinical Signs

Cats are masters at hiding oral pain. Many cats with TR show no obvious clinical signs. When present, clinical signs include:

Jaw chattering when the lesion is touched during examination
Increased salivation (ptyalism) or drooling
Head shaking or pawing at the mouth
Dropping food or difficulty eating (dysphagia)
Preference for soft food
Weight loss and anorexia in advanced cases
Focal gingival redness or hyperplasia over affected tooth

Clinical and Radiographic Findings

NAVLE TipOn the NAVLE, remember that tooth resorption is NOT the same as dental caries. Caries are caused by bacterial fermentation of carbohydrates and are extremely rare in cats. TR is caused by odontoclastic resorption and is NOT bacterially mediated.

Type	Radiographic Features	Treatment
Type 1	Normal root density in some areas Visible periodontal ligament space (dark line around root) Definable root canal Often associated with periodontitis	COMPLETE EXTRACTION Crown AND all roots must be removed
Type 2	Replacement resorption (root replaced by bone) No visible periodontal ligament space No visible root canal 'Ghost roots' appearance in advanced cases Dentoalveolar ankylosis present	CROWN AMPUTATION acceptable if no periodontitis, endodontic disease, or stomatitis
Type 3	Combination of Type 1 and Type 2 in same tooth One root may show Type 1, another Type 2 Only occurs in multi-rooted teeth	INDIVIDUALIZED Each root treated based on its type

TR Classification System

The AVDC classifies tooth resorption by two parameters: Type (based on radiographic appearance) and Stage (based on extent of tissue destruction). CRITICAL: Type determines treatment; Stage indicates severity.

Types of Tooth Resorption

Stages of Tooth Resorption (AVDC Classification)

High-YieldStages 1-4 are PAINFUL and require treatment. Stage 5 with complete gingival coverage does NOT require treatment. TYPE determines the surgical approach; STAGE indicates disease severity.

Stage	Description	Clinical Notes
Stage 1	Mild dental hard tissue loss affecting cementum or cementum and enamel only; no dentin involvement	Rarely detected clinically; may see with explorer; often subgingival
Stage 2	Moderate hard tissue loss extending into dentin but NOT to pulp cavity	Painful; granulation tissue may be visible; tooth integrity intact
Stage 3	Deep hard tissue loss extending to pulp cavity; tooth still retains most integrity	Very painful; pulp exposure; extraction indicated
Stage 4	Extensive hard tissue loss; tooth integrity lost. Subdivided: 4a (crown and root equally affected), 4b (crown more affected), 4c (root more affected)	Treatment depends on type; extraction or crown amputation
Stage 5	Only remnants visible as irregular radiopacities; gingival covering complete	No treatment required if gingiva intact; confirm radiographically

Periodontal Disease

Periodontal disease is infection and inflammation of the periodontium (gingiva, periodontal ligament, cementum, and alveolar bone). It is the most common oral disease in cats and progresses from reversible gingivitis to irreversible periodontitis.

Gingivitis vs Periodontitis

NAVLE TipIn cats, probing depths greater than 1mm indicate attachment loss and periodontitis. This is different from dogs where 2-3mm may be normal depending on tooth and breed. Cat teeth are SHORT - even 1mm of attachment loss is significant!

Feature	Gingivitis	Periodontitis
Definition	Inflammation of gingiva only	Destruction of PDL, cementum, and alveolar bone
Reversibility	REVERSIBLE with treatment	IRREVERSIBLE - can only halt progression
Clinical Signs	Red, swollen gingiva; bleeding on probing; no attachment loss	Gingival recession, furcation exposure, tooth mobility, bone loss
Probing Depth	Normal (less than 1mm in cats)	Increased (greater than 1mm indicates attachment loss)
Radiographs	Normal alveolar bone height	Horizontal and/or vertical bone loss
Treatment	Professional cleaning + home care	Extraction of affected teeth often required

Feline Chronic Gingivostomatitis (FCGS)

Feline chronic gingivostomatitis (FCGS) is a severe, immune-mediated inflammatory disease characterized by ulcerative and/or proliferative inflammation extending beyond the gingiva into the oral mucosa, particularly in the caudal oropharynx (lateral to palatoglossal folds).

Key Features of FCGS

Location: Inflammation extends BEYOND mucogingival line into alveolar/buccal mucosa and caudal oropharynx
Appearance: Bright red, cobblestone appearance; ulcerative or proliferative; bleeds easily
Pain: Severe - cats may be anorexic, drooling, have halitosis, difficulty eating
Etiology: Aberrant immune response to plaque antigens; calicivirus implicated; NOT caused by FeLV/FIV alone
Association: Often concurrent with severe periodontitis and tooth resorption

FCGS Treatment Protocol

High-YieldFCGS is distinguished from simple gingivitis by extension BEYOND the mucogingival line. The gold standard treatment is dental extraction, which provides cure or significant improvement in 85-90% of cases. Do NOT confuse with routine periodontal disease!

Treatment	Details and Efficacy
Dental Extractions	GOLD STANDARD treatment. Start with partial mouth extraction (all premolars/molars). Success rate: 55-60% cure, 30-35% significant improvement, 10% no improvement Full mouth extraction if partial fails after 1-4 months
Medical Management	Used as adjunct or for refractory cases: Corticosteroids (temporary relief, not curative) Cyclosporine (immunomodulation) Antibiotics (amoxicillin, metronidazole) - transient effect only
Contraindications	Crown amputation is NOT appropriate for FCGS - complete extraction required

Diagnostic Approach

Full-mouth dental radiographs are MANDATORY for proper diagnosis and treatment planning in feline dental disease. Clinical examination alone misses significant pathology - studies show radiographs detect 2.4 times more affected teeth than visual examination alone.

Diagnostic Steps

Awake examination: Assess facial symmetry, oral odor, visible lesions, palpate mandibles
Anesthetized oral examination: Required for complete assessment; probe all teeth; use dental explorer
Full-mouth dental radiographs: Essential for TR classification, periodontal bone loss assessment, retained roots
Dental charting: Document all findings using Modified Triadan system
Histopathology: Consider for unilateral lesions or suspected neoplasia

NAVLE TipOn the NAVLE, if given a question about feline dental disease diagnosis, dental radiographs are almost ALWAYS the correct answer for determining treatment approach. You cannot choose between extraction and crown amputation without radiographic confirmation of TR type!

Condition	Appropriate Treatment	Contraindications
Type 1 TR	Complete surgical extraction of crown AND all roots	Crown amputation NEVER appropriate for Type 1
Type 2 TR	Crown amputation with intentional root retention acceptable	NOT for: FeLV/FIV+, periodontitis, endodontic disease, stomatitis
Type 3 TR	Individualized approach per root based on type	Requires careful radiographic assessment of each root
Stage 5 TR	No treatment if gingiva intact	Confirm with radiographs; monitor

Treatment Options

Tooth Resorption Treatment Summary

High-YieldCrown amputation is ONLY appropriate for Type 2 TR with confirmed replacement resorption (no visible PDL space or root canal on radiographs). NEVER perform crown amputation if: (1) PDL space visible, (2) patient FeLV/FIV positive, (3) concurrent periodontitis, (4) endodontic disease present, or (5) stomatitis present.

Extraction Techniques

Closed extraction: Used for single-rooted teeth and teeth with significant attachment loss. Involves gingival incision, elevation, and extraction without bone removal.

Open (surgical) extraction: Required for multi-rooted teeth and periodontally intact teeth. Involves mucoperiosteal flap, alveolectomy, tooth sectioning, and flap closure.

Crown amputation: Crown is removed at alveolar margin; resorbing root tissue reduced to 1-2mm below bone level; flap closure allows bone to fill defect. Only for Type 2 TR without contraindications.

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