d. Periodontal probing: histologic and clinical interpretation
Periodontal probing is a clinical procedure that allows the clinician to estimate the
structural status of the periodontal tissues by mechanically probing the gingival sulcus
region. Probing depth allows the clinician
to make certain assumptions about the state of health of the periodontium.
Fig.
52: Diagrammatic view of the healthy gingiva. (From Page, R. and Schroeder, H.E.,
1976). Note the intact collagen fibers (CO) that fill the major connective
tissue compartment and the shallow gingival sulcus (GS). Few inflammatory cells are
present in the connective tissue or the junctional epithelium (JE). AC, alveolar crest;
FI, fibroblast; JE, junctional epithelium; L, lymphocyte; N, neutrophil;
OE, oral epithelium; P, plasma cell; PDL, periodontal ligament; SE, sulcular epithelium;
V, blood vessel.
The healthy gingiva is relatively resistant to penetration by a periodontal probe
inserted into the sulcus with gentle pressure (see Fig. 54 and 56). The probe tip may
distort the gingival sulcus, but is unlikely to penetrate into the non-inflamed tissues.
Fig. 53: Diagrammatic illustration of chronically inflamed gingiva. (From Page, R. and Schroeder, H.E.,
1976). An inflammatory cell infiltrate of plasma cells (P) and lymphocytes (L) has
destroyed the collagen fibers adjacent to the junctional epithelium (JE). Venules (V) leak
serum and inflammatory cells. Finger-like extensions of junctional epithelium
extend into the inflamed connective tissue. Although the gingival sulcus (GS) is
still shallow, the inflamed tissue is much less resistant to penetration by a periodontal
probe inserted through the gingival sulcus than healthy tissue. The probe would
disrupt the blood vessels, causing bleeding on probing and would likely penetrate the
tissue until intact collagen fibers would provide resistance to further penetration (see
Fig. 55 and 56).
Fig. 54: Periodontal probing of a healthy gingiva. The periodontal probe tip is just
below the gingival margin, within the gingival sulcus. The probe tip is putting
pressure on the gingival tissues causing them to blanch (compare with the color of the
adjacent gingiva). However, the tissues offer enough resistance to the probe
pressure to prevent tissue penetration.
Fig. 55: Periodontal probing of the chronically inflamed gingiva of a patient with
periodontitis. The periodontal probe tip is located about 8 mm apical to the
gingival margin. The apical location of the probe tip is due, in part, to the
presence of a periodontal pocket as well as penetration of the collagen-poor, chronically
inflamed tissues adjacent to the pocket. Although not present in this case,
bleeding on probing is a frequent finding.
Fig. 56: Diagrammatic representation of the location of the probe tip in healthy gingiva
(A), mildly inflamed gingiva (B), and severely inflamed gingiva (C). In non-inflamed
gingiva, the probe distorts the gingival sulcus, but does not penetrate into the tissues.
In mildly inflamed gingiva, the probe penetrates the junctional epithelium (JE) to varying
degrees. In severely inflamed gingiva the probe tip may pass through the epithelium and
adjacent inflamed connective tissue (ICT) and end up at the level of the non-inflamed
connective tissue (NCT).
