A systematic approach is necessary when diagnosing oral pathology in the dog and cat. This should always include a thorough clinical examination of other organ systems before the oral examination begins.
The oral examination will include inspection and palpation of the extraoral structures, including the face, lips, and muscles of mastication; temporomandibular joints; salivary glands; lymph nodes; maxillae and mandibles; and looking for swelling, atrophy or asymmetry. Inspection of the intraoral structures should follow, including the hard and soft tissues with the focus on the dentition, gingiva, mucosa, tongue, tonsils and occlusion. On visual inspection, an animal with periodontal disease may show evidence of gingival swelling, redness and altered gingival contour around the teeth. There may also be areas with gingival recession, furcation exposures (in multirooted teeth) or purulent discharge from periodontal pockets. There can be variable amounts of plaque and calculus present, although as a general rule, the more plaque and calculus covering the tooth surface, the more severe the disease.
1. Oral Examination
Periodontal probe with graduations up to 10 mm; sickle explorer other end
Protective eyewear with or without magnification
Good light source with cold beam
Disclosing solution to detect plaque
Digital camera with macro capability
Dental radiography can be performed with a general X-ray unit, but a dental X-ray unit is preferred. The dental X-ray unit can be mobile or fixed to a wall to allow radiographs to be taken directly at the workbench. Dental X-ray equipment: non-screen dental films, film clips for handling, and envelopes for radiographic storage or you can digitalise radiographs for storage on computer hard drive. Useful inclusions: Chair-side developer with rapid developer/fixer, ideally radiographic viewing box.
Digital radiography has already started to replace screen film/darkroom processing in many veterinary teaching universities in Australia. There is an increasing uptake of digital radiography in human dentistry also. It will not be long before this trend takes over from analogue systems in the veterinary dental field.
3. Dental Charting and Recording
Periodontal probing and charting: As periodontitis is a disease of the periodontium and involves the loss of periodontal attachment to the tooth, the only way to assess this loss is by assessing the extent of disease (by probing and radiography) and recording this information.
Periodontal probing with a blunt-ended probe measures the depth of the gingival sulcus or pocket. Probing provides a practical way of assessing periodontal health or disease. Normal sulcus depth in the dog is < 3 mm and < 1 mm in cats. The probe is held in a modified pen grip with a finger rest, and it is placed parallel to the long axis of the tooth. With light pressure, the probe is gently walked around the tooth to measure pocket depth. If gingival recession is present, the periodontal probe can also be used to measure this recession. The measurement (to the nearest mm) is taken from the cementoenamel junction to the free gingival margin. Where recession is present, the addition of the recession and pocket measurements gives the attachment loss (AL) measurement for that particular tooth surface. Bleeding on probing (BOP) can also be noted at this time, as it is often an early sign of active inflammation at that site.
In humans, the severity of periodontitis is based on a number of findings, including tooth mobility, BOP, AL, furcation involvement, purulent discharges from pockets, and tooth pain associated with percussion or thermal sensitivity testing. A prognosis is then assigned to each tooth.
As well as the periodontal probe, the dental explorer is a useful tool when examining teeth for pulpal exposures, external resorptive lesions, furcation involvement, and dental caries. It can also be used post-root debridement to assess the presence of residual calculus. A dental mirror may also aid in examining the palatal and lingual surfaces of teeth.
All findings should be recorded on a dental chart. Missing, rotated, and fractured teeth; probing depths (up to 6 points per tooth) of gingival recession; and hyperplasia, mobility, furcation involvement and other oral pathology can all be recorded on a dental chart. Charting not only records the current state of the dentition and soft tissues of the oral cavity, allowing the formulation of a treatment plan, but also provides a permanent record for future comparisons.
Common Indices Used in Veterinary Dentistry
Periodontal Disease Index
Can be generalised or localized
Stage 0 - No disease
Stage 1 (PD1) - Gingivitis - reversible, no attachment loss (AL*)
Stage 2 (PD2) - AL < 25% or furcation 1 exposure
Stage 3 (PD3) - AL 25%–50% or furcation 2 exposure
Stage 4 (PD4) - AL > 50% or furcation 3 exposure
*AL is usually best based on measurements with a periodontal probe and intraoral radiographs.
Calculus Index (CI)
Usually used as a whole mouth score
0 = No calculus
1 = Some supragingival calculus covering < 1/3 buccal tooth surface
2 = Moderate calculus covering 1/3 to 2/3 buccal tooth surface with minimal subgingival deposit
3 = Heavy calculus covering > 2/3 of buccal tooth surface and extending subgingivally
Gingival Index (GI)
Usually used as a whole mouth score
0 = Normal gingiva
1 = Marginal gingivitis, mild swelling, some colour change, no BOP
2 = Moderate swelling and inflammation of gingiva, BOP
3 = Marked swelling and inflammation, spontaneous bleeding
Plaque Index (PI)
Usually used as a whole mouth score
0 = No plaque
1 = Thin film along gingival margin covering < 1/3 of buccal tooth surface
2 = Moderate accumulation of plaque covering 1/3 to 2/3 of buccal tooth surface
3 = Abundant soft plaque covering > 2/3 buccal tooth surface
Used for each multirooted tooth
F1 = Probe goes into furcation and up to 1/3 buccolingual crown width of multirooted tooth
F2 = Probe goes up to 2/3 buccolingual crown width of multirooted tooth
F3 = Probe goes all the way through buccolingual crown width of multirooted tooth
Tooth Mobility (M)
Used for each tooth
M1 = Slight mobility > 0.2 mm, less than 0.5 mm
M2 = Moderate mobility, > 0.5, less than 1 mm in any lateral direction
M3 = Severe mobility > 1 mm or intruded into socket or can be extruded out of socket
Used for each tooth
1 = Lesion in enamel, cementum
2 = Penetration into dentine
3 = Penetration further into dentine, close to pulp
4 = Significant coronal tooth loss
5 = Crown lost
Triadan Tooth Numbering System
Right upper is 1; left upper is 2; left lower is 3; right lower is 4
Canine teeth always end in 04, i.e., left mandibular canine is numbered 304
Maxillary PM4 (dogs) ends in 08. Mandibular 1st molar tooth (dog) ends in 09, i.e., right mandibular 1st molar is numbered 409
Maxillary PM4 (cat) ends in 08. Mandibular 1st molar (cat) ends in 09, i.e., right maxillary premolar 4 is numbered 108
Apical - toward the apex of the tooth
Buccal - surface of tooth toward cheeks
Labial - the surface toward the lips (applies to incisors, canines)
Coronal - toward the crown
Incisal - toward the tip of the tooth (for incisors, canines)
Distal - surface away from midline of animal
Facial - can be labial or buccal surface
Interproximal - surface between two teeth
Lingual - surface of tooth toward tongue
Mesial - surface toward rostral midline of animal
Occlusal - biting surface of tooth (applies to maxillary molar 1 and 2 in dogs)
Palatal - surface of tooth toward hard palate
Supragingival - above the free gingival margin (gum line)
Subgingival - below the free gingival margin (gum line)
Uncomplicated crown fracture - fracture of crown of tooth not involving the pulp
Complicated crown fracture - fracture of crown of tooth involving the pulp
BOP - bleeding on probing with light pressure with a blunt periodontal probe
Sequence of Dental Charting
Select where you would like to start. In human dentistry, usually start most distal tooth in quadrant 1, and then work way around quadrant 2, 3 and finally 4. Record both the buccal and lingual sides of teeth. This works well in veterinary dentistry also. All recordings can be transcribed to an assistant. This saves time and prevents cross infection. In the USA, the veterinary technician is trained to perform this step as well as take radiographs and perform the dental scale and clean.
1. Count the teeth and note missing or extra teeth. Record head type and any malocclusions, rotated and mobile teeth, fractured teeth including pulp exposures, enamel defects, tooth resorptions, caries, abrasion, attrition, gingival recession (record recession line on chart) or any other notable pathology
2. Determine the level of calculus, as per the CI above
3. Use disclosing solution to determine location and level of plaque, or use quantitative light-induced fluorescence (QLF) technique in a darkened room. QLF technique detects red fluorescing porphyrins produced by oral bacteria attached to the tooth surface
4. Use plaque score (PI)
5. Determine the level of gingival inflammation (GI); see above. Using a blunt, thin periodontal probe parallel to the tooth surface, gently run the probe around the buccal sulcus to determine the degree of gingival inflammation. Avoid too much apical pressure. Usually record 6 probing depths for large and important teeth such as canine, carnassial teeth, and molar teeth. Measure 4 probing depths for incisors and premolar teeth.
6. Remove gross calculus to allow for periodontal probing.
7. Periodontal probe in 4–6 places, depending on tooth.
8. Record all findings on dental chart.
9. Diagnosis and formulate treatment plan.
A number of practices utilise trained veterinary technicians and nurses to do the initial oral examination. Pathology is pointed out to the client and then the veterinarian performs the oral examination and points out the same pathology to the client, thus reinforcing the recommendations given to the client by the technician. This assists with compliance immeasurably, because the message is delivered more than once (repeating the same message aids in improving compliance).
Some practices use a dental scale from zero to four (zero being no disease to 4 being severe periodontitis) to grade every mouth. Although grading periodontal disease based only on an oral examination in the conscious animal has got its limitations, applying a grade to the disease can stress to the client the importance and the timeframe for treatment. Grading also allows all of the practice staff to be on the "same page" in recognizing the severity of the disease. Treatment and homecare recommendations made to the client should be recorded on the pet's chart and clinical notes to assist in future followups.
The most common diagnostic tools used in veterinary dentistry include the periodontal probe/sickle explorer, intraoral radiography, and plaque disclosing tools including QLF instrument and disclosing solution. Less common tools include furcation probes and CT imaging.
Periodontal Probe/Sickle Explorer
The periodontal probe is primarily used to measure pocket depth from the free gingival margin to the base of the periodontal sulcus or pocket (where the gingival epithelium attaches to the tooth surface).
A common periodontal probe used in veterinary dentistry is the Williams probe, which has etched circumferential lines measuring periodontal probing depths from 1 to 10 mm. The first marking visible above the gingival margin is the probing depth measurement. Periodontal probes can also be used to measure other dental instruments, tooth preparations during restorative procedures, gingival recession, attached gingiva, or other oral pathology.
Intra- and Extraoral Radiography
Some of the indications for dental radiography include:
1. Periodontal disease - assessment of bone levels, type of bone loss, combined periodontal-endodontic lesions, success or failure of periodontal therapy
2. Endodontic disease including apical pathology, pulp exposures, and draining fistulae
3. Pathology of the oral soft and hard tissues, including tumours and fractures
4. Temporomandibular joint dysfunction
5. Crown/root pathology including tooth resorption lesions, crown or root fractures, extra roots, dilacerated roots
6. Pre/post tooth extraction
7. Root canal therapy
8. Oligodontia/supernumerary teeth, especially in breeds with a family history of missing or extra permanent teeth
9. An assessment of tooth development and chronological dental age of the animal
Plaque Disclosing Methods
The use of a plaque disclosing dye (IC plaque, iM3) on the teeth will demonstrate to the owner the extent of the problem. Plaque fluorescence device (QLF light) can also detect mature plaque on teeth.