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3 steps to effective periodontal disease diagnosis


Visual examination, anesthetized probing and intraoral radiography can help you assess each patient’s level of disease.

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Most pet owners are unaware their dogs or cats have periodontal disease. They think their animals' malodorous breath is normal and expected.

Unfortunately, many of these loved pets wind up suffering needlessly while their diseases progress, often to the point of surgical extraction. What can you do in the early stages to make a difference?

Embrace the concept that periodontal disease is not a one-size-fits-all malady diagnosed when the odor is so bad you need to leave the exam room doors open, bleeding of the gingiva is visible upon light wiping with gauze and affected teeth are mobile. Periodontal disease encompasses myriad presentations, treatments and outcomes. Diagnosis is the key to unlocking the puzzle early.

To be sure, diagnosing which type and the severity of disease is neither easy nor simple, but it is important and doable in general practice. Exam room visual diagnostics, anesthetized probing and intraoral radiographs are the steps to achieve periodontal diagnostic success.

Step 1: Visual examination

Regardless of what a patient is presented for, every thorough physical examination must include the face and oral cavity. The mouth should not be bypassed because an animal comes in for, say, a skin problem. Often, because the teeth are out of sight, they're also out of mind until advanced disease is noted.

By gently raising the upper lips, most of the buccal surfaces of the teeth, gingiva and oral mucosa can be observed for inspection (Photo 1A).

Photo 1A:

A doctor taking an exam room image of a dog's periodontal inflammation.

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Additionally, this is a good time to take a digital image (if your practice is so equipped) of what you see, download it to a computer screen or tablet and then print it for the client to take home (Photo 1B).

Photo 1B:

The image is wirelessly transmitted to an iPad for the doctor to share with the client.

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OraStrip (PDx BioTech), a small strip you can swipe along a patient's oral mucosa, turns from white to yellow in front of your client's eyes if the pet is producing significant thiols secondary to anaerobic bacteria from periodontal disease. When the strip color is compared to the supplied chart, the client can visually appreciate the problem that needs addressing (Photo 2). We use OraStrip diagnostic tests in every animal's semiannual and annual examination, and every day we get cases that visually appear normal but have abnormal strip test scores that, upon closer inspection under anesthesia, turn out to be significant periodontal disease.

Photo 2:

An OraStrip score of 5, indicating high levels of thiols consistent with advanced periodontal disease.

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Step 2: Anesthetized probing

Next, while the animal is under anesthesia, examine each tooth for mobility, probing depths and bleeding upon probing

Slight tooth mobility is considered normal. Greater than 0.2 mm is abnormal and could be caused by trauma or, more commonly, advanced periodontal disease. To check for tooth mobility, use a periodontal probe to push against the tooth crown. Record mobility findings such as the following in the medical record:

  • Stage 0 (M0): The physiologic mobility is up to 0.2 mm.

  • Stage 1 (M1): Mobility is increased in any direction other than axial over a distance of more than 0.2 mm and up to 0.5 mm.

  • Stage 2 (M2): Mobility is increased in any direction other than axial over a distance of more than 0.5 mm and up to 1 mm.

  • Stage 3 (M3): Mobility is increased in any direction other than axial over a distance exceeding 1 mm, or axial movement is present (Photo 3).

Photo 3:

Stage 3 mobility in a maxillary canine.

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Every professional oral hygiene procedure conducted under general anesthesia should include probing and charting. To determine the probing depth, insert the periodontal probe into the gingival sulcus, and record the findings in millimeters (Photo 4).

Photo 4: Millimeter markings on a Williams before insertion.

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There are two methods of probing:

  • Spot probing is the insertion and withdrawal of the probe at a single area per tooth (Photo 5). Because single areas don't represent the entire tooth, an inaccurate assessment may be obtained.

  • Circumferential probing is the insertion of the probe in the sulcus or pocket in at least four places (two buccal and two lingual or palatal) around the tooth. This method compensates for inaccurate readings when subgingival calculus or isolated areas of vertical bone loss are present.

Photo 5:

A 6-mm probing depth.

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Cats normally have probing depths less than 1 mm. In dogs, there's great variability of probing depth scores, depending on a dog's size and tooth location. For a typical 25-lb dog, a 2- to 3-mm probing depth around the canines is considered normal. Greater depths may indicate periodontal disease requiring further evaluation and treatment (Photo 6).

Photo 6:

An 8-mm probing depth between the maxillary fourth premolar and first molar.

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Finally, bleeding on probing doesn't occur in healthy tissue unless abnormally traumatized by the probe. Gingival bleeding is an objective, easily assessed sign of inflammation associated with periodontal diseases (Photo 7).

Rare causes of gingival bleeding may include hemophilia, leukemia, thrombocytopenia and liver and kidney disease. More commonly, bleeding is secondary to gingival inflammation due to inadequate plaque and tartar removal beneath the gum line. Gingival bleeding on probing indicates an inflammatory lesion in the epithelium and connective tissue.

Photo 7:

Bleeding on probing on a maxillary first premolar in a dog.

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If you encounter bleeding during pocket-depth probing (Photo 8), stop immediately to document, diagnose and react (see Periodontal probing: Stop when you see red in the June 2012 issue).

Photo 8:

Bleeding on probing on a left mandibular canine in a cat.

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Step 3: Intraoral radiography

To walk the talk of veterinary dentistry, intraoral radiography is essential. Exam room diagnostics, as well as probing and mobility examinations, are important, but intraoral radiography provides the most information. Yet, to date, it hasn't become routine in most practices.

Three of the four structures composing the periodontium (cementum, periodontal ligament and alveolar bone) are located below the gum line out of visual view. Radiography is the best way to determine what lies beneath the fourth component, the gingiva.

Severe periodontal disease appears radiographically as loss of bone support around one or more roots. Bone loss may be horizontal (a decrease in bone height around one or more teeth), vertical (infrabony defect) or oblique (a combination of both) (Photo 9).

Photo 9:

An intraoral radiograph of a mandibular first molar showing Stage 2 periodontal disease.

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When more than 50 percent of the bone and tooth support remains (Photo 10), periodontal procedures-together with a healthy patient and stringent home care-often will result in a saved tooth. A guarded prognosis is given when bone loss is greater than that.

Photo 10:

An intraoral radiograph showing Stage 3 periodontal disease (less than 50 percent bone loss); the white arrow is pointing to calculus.

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If the loss more than 75 percent, support is lost, and the prognosis for saving the tooth is poor (Photo 11).

Photo 11:

An intraoral radiograph showing Stages 2, 3 and 4 periodontal disease in a patient's left mandibular cheek teeth.

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Client communication: Before and after

Your clients are important partners in periodontal diagnostics, treatment and prevention. It's up to them to approve the initial plan of examination under anesthesia with intraoral radiographs and to understand that periodontal disease or other oral problems may be uncovered that should be addressed while the animal is still anesthetized. Set a time (usually two to three hours after the initial inspection in the exam room) for the owner to call to ask what was found after the tooth-by-tooth examination under anesthesia and for the staff to gain client compliance for additional care if needed.

From the beginning, fees should be discussed, but there's no way of knowing what stage of disease exists without at least an in-person examination. Review known fees (e.g., examination, required preanesthetic testing, intravenous fluids, anesthesia, dental radiographs, dental scaling), with the knowledge that there most probably will be additional fees, which may be significant, required to correct issues uncovered once the thorough examination is conducted. Thanks to third-party payment plans, needed treatment often can be paid over time.


Periodontal disease affects most of our patients. With exam room diagnostics, anesthetized probing and intraoral radiography, its diagnosis is within grasp of every practitioner.

Periodontal disease names through the ages

Scientists and dentists have been trying to understand, diagnose and treat periodontal disease for centuries, as witnessed by the number of names the condition has been given. Depending on the era, periodontal disease has been referred to as loculosis, blennorrhea gingivae, periostitis, alveolodental periostitis, infectious arthrodental gingivitis, phagedenic pericementitis, expulsive gingivitis, symptomatic alveolar arthritis, Schmutz pyorrhea, Riggs' disease, periodontoclasia, pyorrhea alveolaris and, most recently, the general term periodontal disease, including several specific diseases, such as gingivitis and periodontitis.

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