| Working ends of an ODU 11/12 explorer, left, and an UNC periodontal probe, right.
Courtesy of John Lewis, VMD, BVMS, Dipl. ACVS
In last month's column, we discussed the components of the conscious intraoral and extraoral examination. The conscious examination, however, reveals only so much.
A comprehensive oral examination requires anesthesia to obtain a complete assessment of oral health and disease. In particular, the periodontium (the attachment structures of the teeth) cannot be evaluated without using a probe at multiple sites around each tooth.
Each patient deserves an individual treatment plan based on appropriate diagnostics. The same hold true for teeth: The adult dog's mouth contains 42 patients and the adult feline mouth contains 30 patients that require individual attention.
Use your dental probe, explorer and dental radiographs to determine if each and every tooth will be able to provide pain-free function or if it is non-salvageable.
Start the anesthetized exam by assessing those structures that were not adequately assessed in the conscious examination: tonsils, pharynx, soft palate, caudal tongue, caudal buccal mucosa. Identify each of these structures as normal or abnormal and document this information on the dental record.
Determine the presence or absence of teeth in each quadrant. Missing teeth can be documented on the dental chart by darkening or circling the missing tooth.
Radiographic evaluation of areas of missing teeth is imperative because dentigerous cysts can form in areas of an unerupted tooth. A periodontal probe and dental explorer are used to evaluate the tooth and its attachment structures.
These dental instruments are important clinical tools for obtaining data about the health status of each tooth. The periodontal probe is used like a miniature intraoral ruler to measure attachment levels, sulcus and pocket depths, loss of bone in furcation areas and size of oral lesions.
The probe is also used to assess the mobility of teeth and the presence of gingival bleeding. Periodontal probes are available in an assortment of styles, with variations in thickness of the diameter of the working end and variations in increments of millimeter markings. A good multi-purpose probe for the general practitioner is the UNC 15.
The dental explorer tapers to a sharp point. It is used to explore the topography of the tooth surface and to locate tooth surface irregularities, including caries, tooth resorption, calculus deposits and pulp exposure.
Several designs of explorers are available. A shepherd's hook explorer (#23) is often found on the opposite end of many periodontal probes, though this explorer can be somewhat bulky for assessment of subtle lesions in cats. A good multi-purpose explorer for use in veterinary dentistry is the ODU 11/12.
The assessment of the periodontium and teeth should begin at the midline of the mouth and systematically evaluate each tooth via visual observation and use of the probe/explorer.
Begin detecting excessive tooth mobility: tooth movement is estimated on a scale of 0, 1, 2 or 3, based on the distance beyond normal physiologic mobility the tooth moves in one direction. A slight amount of movement is normal as a result of the periodontal ligament that connects the tooth to alveolar bone. The most severe category of mobility, a classification of 3, includes any tooth with vertical movement.
The probe is gently inserted into the sulcus (anatomic term) or pocket (pathologic term if sulcus is deeper than normal), ensuring that the probe is kept as close to parallel to the long axis of the root as possible.
When resistance is felt at the base of the sulcus or pocket, note the depth of the probe measured to the gingival margin. The probe is then lifted and "walked" around the tooth to assess the entire circumference of the tooth. Abnormal measurements (those greater than 3 mm in dogs, greater than 1 mm in cats) should be noted on the dental chart along with the specific location of the pocket measurement (i.e., M for mesial, P for palatal).
In areas where the height of the free gingival margin has migrated apically, the probe is used to measure gingival recession. Recession is measured in millimeters from the CEJ to the level of the gingival margin.
"Attachment loss" is a term that truly describes the periodontal state of a tooth because it accounts for both pocket depth and gingival recession. Gingival hyperplasia occurs when the free gingival margin migrates toward the crown of the tooth. An increased pocket depth may be due to hyperplasia or attachment loss, so clinical examination findings are necessary to determine if the increased probing depth is due to a true periodontal pocket or a pseudopocket.
When multi-rooted teeth are approached, the probe is used to assess loss of bone in the areas between the roots. The extent of bone loss determines the furcation classification.
Stage 1 furcation exposure occurs when the probe extends into the furcation, but does not extend further than half the width of the tooth.
Stage 2 furcation exposure occurs when the probe extends into the furcation greater than half the width of the tooth.
Stage 3 furcation exposure occurs when the probe enters the furcation on the outer surface of the tooth and exits beyond the palatal or lingual side of the tooth (through and through furcation exposure).
During the periodontal evaluation of each tooth, also observe the hard structures of the tooth and use the dental explorer when noticing any fractures, pulp exposure, tooth resorption or abnormal wear patterns.
"Abrasion" refers to tooth wear associated with aggressive chewing on external objects, such as toys, rocks, bones, antlers and ice cubes. "Attrition" refers to tooth wear associated with tooth-to-tooth contact, such as that seen in patients with malocclusion.
When tooth fractures are present, gently drag the sharp point of the explorer across the tooth surface, feeling for any openings into the pulp. Teeth with significant abrasion may have a brown or black spot in the center of the worn tooth. This can be a sign of either chronic pulp exposure or a reparative material produced by the tooth in response to chronic wear (tertiary dentin).
Pulp exposure can be distinguished from tertiary dentin with an explorer. If a tooth has pulp exposure, the tip of the explorer will fall into a hole, whereas a discolored area caused by tertiary dentin will feel smooth as glass when the explorer is run over this area.
This is an important clinical distinction because treatment of pulp-exposed teeth is necessary, but worn teeth without pulp exposure often require no treatment if radiographically normal.
Use the explorer to check for clinical signs of tooth resorption by dragging the sharp point horizontally across the cervical portion of each tooth. Sometimes it is challenging to determine whether a concavity in the area of a furcation is a resorptive lesion or merely Stage 1 furcation exposure. If tooth resorption is present, the explorer tip will catch on the edge of the concavity, whereas the explorer will freely move out of the concave area as easily as it fell into it when encountering mild furcation exposure.
I hope this review will provide you with the information necessary to assess each and every tooth. A systematic approach allows for efficiency and thoroughness. A thorough examination takes time, but it's the only way to make educated treatment decisions.
Dr. Lewis, FAVD, Dipl. AVDC, practices veterinary dentistry and oral surgery at NorthStar Veterinary Emergency Trauma & Specialty Center in Robbinsville, N.J.
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