Probing is your future
by Jan Bellows, D.V.M.
Diplomate, American Veterinary Dental College
Diplomate, American Board Veterinary Practitioners
How many veterinarians or technicians routinely use a periodontal probe in as
part of every dental prophylaxis? Why use a periodontal probe? What
information can be learned and how can this help our patients?
A periodontal probe is the primary instrument used in gingival examination.
The only accurate method of detecting and evaluating periodontal pockets is
careful exploration with a periodontal probe. Pockets are not reliably
detected or measured by radiographic examination. Periodontal pockets are
soft tissue changes. Radiographs indicate areas of bone loss where pockets
may occur but do not show whether pockets are present and do not reveal
pocket depth. The probe's use can give the practitioner invaluable
information concerning gingival bleeding, an important sign of inflammation,
and determine the depth, shape, and tissue characteristics of
the pocket.
Design of the probe
Probes vary in cross-sectional design and millimeter markings. They may be
rectangular (flat), oval, or round. The calibrated working end is marked in
millimeters at varying intervals to facilitate reading of depth
measurements.
The Marquis probe is color-coded by alternately colored bands which mark
3,6,9, and 12 mm.This probe has a good, thin working end. Care must be taken
in estimating the millimeter readings between the markings.
The Williams probe is marked at 1,2,3, then 5, 7,8,9, and 10 millimeters. The
spaces between 3 and 5 are important to note because most pockets deeper than
five millimeters will need surgical
care (flap procedure or extraction). Be careful when purchasing a Williams
probe because some manufacturers produce a working end which is too thick to
allow easy insertion.
The Michigan-O probe is marked at 3,6, and 8 millimeters. Many veterinarians
prefer this probe because it has a very thin working end. The Michigan-O
probe can be obtained with Williams markings.
Use of the probe
Periodontal measurements are taken by inserting the probe under the free
gingival margin and gently moving it down to the bottom of the pocket
(junctional epithelium). Keep the probe parallel to the tooth surface to
insure correct measurement. After inserting gently "walk" the tip along the
bottom of the pocket. This walking technique allows an accurate measurement
of the level of attachment around the tooth. The measurements are recorded at
four to six points on each tooth.
Depths are measured from the base of the pocket to the margin of the free
gingiva. Normals for dogs are 2-3mm cats 1-2mm. The level of attachment of
the epithelium at the base of the pocket to the tooth surface is of greater
diagnostic significance than the probing depth of the pocket. The level of
attachment is determined by subtracting from the total depth the distance
from the gingival margin to the cement-enamel junction (CEJ). When the
gingival margin coincides with the CEJ, the level of attachment and the
pocket depth are equal; when the gingival margin is located apical to the
CEJ, the loss of attachment will be greater than the pocket depth.
So how does this help the veterinarian? If all the probing depths are normal
the client is informed all is well. If there are areas of abnormal depth,
radiographs are taken and the client advised of a therapy plan ( flap
surgery, hemi-section and endodontics, or extraction). The probe provides
this "under the gum line" look at dental pathology and is an essential part
of every dental examination.