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.