Bad breath, drooling, and facial swelling can be signs of periodontal disease or a periapical abscess.
Periodontal disease begins when bacteria accumulate between the tooth and gum, inflammation progresses, and the supporting bone is lost.
A periapical abscess forms after the pulp dies and pus collects at the root tip; when the upper fourth premolar is involved, swelling under the eye (cheek) is typical.
See a Vet if You Notice
Chewing on one side, avoiding hard treats, difficulty eating
Strong halitosis, increased drooling
Red or bleeding gums, tooth mobility
Swelling under the eye or along the jaw; a small draining hole (fistula)
Poor appetite, fever, lethargy
What Are Periodontal Disease and Periapical Abscess?
Periodontal disease: plaque (bacterial film) hardens into tartar, gums become inflamed; as it progresses the alveolar bone resorbs and teeth loosen.
Periapical abscess: tooth fracture or heavy wear leads to pulp necrosis → pus accumulates at the root tip; the upper 4th premolar often causes cheek swelling.
Important: antibiotics alone rarely cure it — the source tooth requires treatment.
Diagnosis
Start with oral examination and probing (pockets, mobility, furcation). Add imaging or culture as indicated.
In general, intraoral dental radiographs are useful for staging and evaluating root tips; in this case they were not taken (we recommend imaging when clinically appropriate).
Treatment Basics
Periodontal disease: scaling & root planing; add periodontal surgery or extraction as needed.
Periapical abscess:root canal therapy or extraction provides definitive care. Remove the source first.
Pain control: tailored to the patient; consider renal/GI risks when choosing NSAIDs.
Antibiotics: short course only when clearly indicated (fever, cellulitis, systemic risk).
Aftercare & Prevention
Soft food for several days; return if swelling, bleeding, or pain persists.
After healing, resume daily toothbrushing; use VOHC-accepted diets/chews.
Avoid very hard chews (antlers, hooves, hard bones) that can fracture teeth.
Regular checkups and professional cleaning help prevent progression.
When to Visit
Sudden swelling under the eye or a small draining hole on the cheek
Strong pain when the mouth is touched, refusal to eat, persistent bad breath
Sadahiro Animal Hospital (Shin-Matsudo, Matsudo City) provides pain control, infection management, and dental procedures (root canal therapy/extraction) as indicated, plus home-care coaching (how to start brushing, tool selection).