Periodontal measurements: indicators of disease and conditions


Several clinical measurements are critical when evaluating overall periodontal status. These measurements can be used to describe a tooth’s stability and loss of support and a patient’s degree of inflammation and pattern of disease. They also help to establish a diagnosis, guide the development of a treatment plan, and document changes following active therapy. Throughout this discussion, references will be made to documenting this information using the clinical chart obtained from the Ohio State University College of Dentistry (Fig. 7-18).

Illustrations A, B, and C show charting of periodontal findings.

FIGURE 7-18. Charting periodontal findings (on a partial reproduction of the form used at the Ohio State University College of Dentistry). This form provides a logical method for documenting periodontal findings (as well as other findings). A. The left column provides the key for recording the following: fremitus is recorded as F as on tooth #5; mobility is denoted by 1 for tooth #2, 2 for tooth #5, and 0 (no mobility) for teeth #3 and #4. Probe depths (six per tooth) are recorded during the initial examination (initial probe depths) in the three boxes for three facial depth locations on each facial surface and three boxes for three lingual depth locations. After initial periodontal therapy has been completed, probe depths should ideally be recorded again in 4 to 6 weeks. They should also be recorded at regular periodontal maintenance therapy appointments. This permits easy comparison to identify sites that respond to treatment and those that do not respond. Bleeding on probing (BOP) is denoted by a red dot over the probe depth readings as on the facial surfaces of teeth #2 (mesial, midfacial, and distal), #3 (distal), and #5 (mesial and distal) and lingually on all mesial and distal surfaces. Gingival margin position is recorded as numbers in red on the root of teeth as follows: +1 (1 mm apical to the CEJ) on the facial of teeth #2 and #3, +2 on the facial of tooth #5, –1 (1 mm occlusal to the CEJ) on the lingual of teeth #3 and #4, and 0 (located at the level of the CEJ) on all other surfaces. Furcation classes are seen as red triangular shapes (incomplete, outlined, or solid). Class I involvement is evident on the midfacial of tooth #3. Class II involvement is noted midfacial on # 2, as well as on the mesial (from the lingual) on # 2, and the distal (from the lingual) on #3. Class III involvement is noted on a mandibular molar discussed below. Loss of attached gingiva (mucogingival defect) is recorded as a red wavy line seen on the facial of tooth #5. B. A mandibular molar (#30) showing a class III furcation evident from the facial and lingual views. Note that the triangle point is directed up toward the furcation in the mandibular arch but was directed down toward the furcation in the maxillary arch as shown in (A). C. Calculation of plaque index % and BOP %. The plaque index % can be calculated by dividing the number of surfaces with plaque by the total number of surfaces (four per tooth). When considering only the four teeth in this figure, nine surfaces had plaque divided by 16 possible surfaces = 56%. The BOP % is the number of tooth surfaces that bleed on probing divided by the total number of surfaces (six per tooth). When considering only the four teeth in this figure, 14 surfaces bled divided by 24 total surfaces = 58%.



Tooth mobility is the movement of a tooth in response to applied forces.22 Teeth may become mobile due to repeated excessive occlusal forces, inflammation, and weakened periodontal support (often associated with a widened periodontal ligament space as noted on radiographs). The healthy periodontal ligament is about 0.25 mm wide, decreasing to only 0.1 mm with advanced age. When a tooth is subjected to forces from chewing (mastication) or bruxism (grinding), movements are minimal at the rotational middle of the tooth root (cervicoapically) and greater at either the cervical or apical end of the root. Thus, there is a functional difference in the width of the periodontal ligament in these three regions. At any age, the ligament is wider around both the cervix and the apex than around the middle of the root, depending upon the amount of rotational movements to which the tooth is subjected. Further, the periodontal ligament of a natural tooth in occlusal function is slightly wider than in a nonfunctional tooth because the nonfunctional tooth does not have an opposing tooth to stimulate the periodontal ligament nor bone cells to remodel.23

Injury to the periodontium from occlusal forces is known as occlusal trauma. It may contribute to destructive changes in the bone, widening of the periodontal ligament, and root shortening (resorption), all of which may contribute to increased tooth mobility. Some of the changes are reversible, meaning that the periodontium can adapt.24 Occlusal trauma is a condition that does not initiate, but may influence, the course of inflammatory periodontal disease under specific circumstances.25

1. Technique to Determine Tooth Movement

To determine tooth mobility, first, stabilize the patient’s head to minimize movement. Next, view the occlusal surfaces and observe movement of the marginal ridges of the tooth being tested relative to adjacent teeth as you use two rigid instruments (such as the mirror and probe handles) to apply light forces alternating fairly rapidly first one way and then another. Observe the tooth for movement in a buccolingual or mesiodistal direction, as well as for vertical “depressibility.” Figure 7-19A and B illustrates the technique to determine tooth mobility. Numbers assigned to denote the extent of mobility are presented in Table 7-2. For simplicity, tooth mobility can be recorded as “0” for no mobility, “1” for slight mobility, “2” for moderate mobility, or “3” for extreme mobility that includes depressing the tooth. See Figure 7-18 for charting examples of mobility (categories 0, 1, 2, or 3).

TABLE 7-2 Numbers Assigned to Mobility Categories

Mobility Category

Clinical Observation



No observed movement



Slight movement

<1 mm


Moderate movement

>1 mm


Extreme movement


An illustration A and a photo B shows the method for determining tooth mobility.

FIGURE 7-19. Method for determining tooth mobility. A. Two rigid instrument handles are applied to the tooth to see if it can be displaced either buccolingually or mesiodistally. For teeth with severe mobility, the tooth can be depressed or rotated (which is category 3 mobility). B. Technique for determining buccolingual mobility. Light, alternating (reciprocating) buccolingual forces are applied and movement observed relative to adjacent teeth.


Fremitus is the vibration of a tooth during occlusal contact. It is determined by placing the nail of the gloved index finger at right angles to the facial crown surface using a light force while the patient is asked to tap his or her teeth, or clench and move the mandible from right to left (excursive movements). If definite vibration is felt, fremitus is confirmed and could be noted as an “F” on a patient’s chart for that tooth (as seen for tooth #5 in Fig. 7-18). If tooth displacement is detected, functional mobility is confirmed. Functional mobility (biting stress mobility) occurs when teeth move other teeth during occlusal function.


Probing the depth of the potential space between the tooth and gingiva (called the gingival sulcus or crevice) is a critical periodontal finding that is routinely performed in dental offices and may indicate the presence of periodontal disease.26,27 A blunt-tipped instrument with millimeter markings called a periodontal probe (Fig. 7-20) is inserted into the gingival sulcus (seen on anterior teeth in Fig. 7-21 and posterior tooth in Fig. 7-22). In the presence of periodontal disease, this gingival sulcus may be called a periodontal pocket. Probing depth (referred to as pocket depth if periodontal disease is present) is the distance from the gingival margin to the apical portion of the gingival sulcus. Probing depths in healthy gingival sulci normally range from 1 to 3 mm. A depth of greater than 3 mm is a possible cause for concern. However, if gingival tissues are overgrown (as may be seen during tooth eruption, or as a side effect from some medications), a pocket depth reading of 4 mm or greater (called a pseudopocket) may be present even in the absence of periodontitis. On the other hand, if there is gingival recession where the gingival margin is apical to the CEJ, there may be shallow probing depths in the presence of true periodontal disease. Therefore, the critical determinant of whether periodontitis has occurred is measured by the amount of attachment loss (to be described shortly).

A photo shows a standard periodontal probe.

FIGURE 7-20. A standard, frequently used periodontal probe. To make measurements easier, there are dark bands at 1, 2, 3, 5, 7, 8, 9, and 10 mm.


Photos A, B, C, D, and E show a periodontal probe in the gingival sulcus.

FIGURE 7-21. Periodontal probe in place in the gingival sulcus. Sequence of probing technique from the mesiofacial aspect of tooth #6 to the distofacial aspect of tooth # 8. (A), (B), (D), and (E) demonstrate the alignment of the probe against the proximal, tapering crown contours. Note that the probe is angled toward the proximal surface with enough buccolingual lean to engage the most interproximal aspect without catching on tissues. C. Midfacial probing. Notice that the depth of this midfacial sulcus is 1 mm deep, and the tissue is so thin that the probe can be seen through it.


Photos A and B show periodontal probe placement technique.

FIGURE 7-22. Periodontal probe placement technique on models. A. Buccal view: Technique for facial (or lingual) probe placement. The probe is guided along the tooth surface, and care is taken not to engage the sulcular gingival tissues. B. Palatal view: Interproximal probe placement. The probe is angled slightly distally on the mesial surface of tooth #3 as it is guided along the tooth surface, so it is not impeded by the interproximal papilla. Although not easily appreciated from this view, it is also angled 10 to 15 degrees to reach the most direct proximal area.


1. Probing Technique

The intent is to probe carefully into a sulcus just to the attachment, although in reality the probe usually impinges on some of the attachment, even in health. The probe should be “walked around” the tooth with a light force to ensure a tactile sense and to minimize probing beyond the base of the pocket. When the depth of the sulcus/pocket has been reached, resilient resistance is encountered. The probe should be angled slightly toward the crown or root surface to prevent it from engaging or being impeded by the pocket wall (seen best midfacially in Fig. 7-22A). Probing depths are generally recorded as the deepest measurement for each of the six areas around each tooth. On the facial surface, three areas are recorded while moving in very small steps within the sulcus starting in the distal interproximal, stepping around to the midbuccal, and finally stepping around to the mesial interproximal (seen when probing the facial surface of tooth #7 in Fig. 7-21 from B to C to D). Interproximally, when the teeth are in proximal contact, the probe should progress toward the contact until it touches both adjacent teeth before angling it approximately 10 to 15 degrees buccal (or lingual) to the tooth axis line (seen most clearly in Figs. 7-21A and D and 7-22B). When there is no adjacent tooth, the probe is not angled. The three facial readings to record are the deepest readings for mesial interproximal, midbuccal, and distal interproximal. Similarly, three areas are recorded while probing around the palatal or lingual aspects of the tooth.


Before any periodontal disease has occurred, the gingival margin level of a young healthy person is slightly coronal to the CEJ, which is the reference point. If the gingival margin is apical to the CEJ, there has been gingival recession, and the root is exposed (seen most obviously in Fig. 7-12B).

By convention, the following denotes the gingival margin level:

  • Negative (−) numbers denote that the gingival margin is coronal to the CEJ. Normally, after tooth eruption is complete, the gingival margin is slightly coronal to the CEJ (about 1 mm on the labial and lingual aspects and about 2 mm interproximally). If the gingival margin is more coronal to the CEJ than those dimensions, there is an excess (overgrowth) of gingiva or the tooth is partially erupted.
  • Zero (0) denotes that the gingiva is at the CEJ. There is no gingival recession.
  • Positive (+) numbers denote recession (the gingival level is apical to the CEJ).

1. Technique to Determine the Gingival Margin Level

When recession has occurred, the distance between the CEJ and the gingival margin can be visually measured with the periodontal probe. If the gingival margin covers the CEJ, the distance from the gingival margin to the CEJ may be estimated by inserting the probe in the sulcus and feeling for the CEJ. The junction between enamel and cementum can usually be felt with the probe, but if this junction is difficult to detect or is subgingival, the probe should be aligned at a 45° angle. Gingival margin levels are charted as “0” (margin is at the CEJ) or a “+” number (apical to the CEJ or recession) or a “–” number (coronal to the CEJ), in red on the roots near the CEJ as seen on the chart in Figure 7-18.


Clinical attachment loss (clinical attachment level) refers to the distance from the CEJ to the apical extent (depth) of the periodontal sulcus. It is a measurement that indicates how much support has been lost and is, therefore, a critical determinant of whether periodontal disease has occurred.

1. Technique to Determine Clinical Attachment Loss

Add the probing depth and the gingival margin level measurements together to obtain the clinical attachment loss. A patient with a 3 mm pocket and a gingival level of +2 (i.e., 2 mm of recession) has 5 mm of attachment loss. A patient with a 3 mm pocket and a gingival level of −2 mm (the gingiva covers the CEJ by 2 mm) has only 1 mm of attachment loss. Study the example of clinical attachment calculation on the tooth in Figure 7-23 where the sulcus depth is 1 mm (Fig. 7-23A) and the gingiva has receded 1 mm (+1 mm loss in Fig. 7-23B), so the total attachment loss is +2 mm. Clinical attachment loss can be severe even with minimal pocket depths if there is considerable gingival recession. On the other hand, there may be no attachment loss even with deep pockets if pseudopockets are present, that is, pockets due to an enlargement of gingiva possibly caused by plaque accumulation next to ill-fitting restoration margins, as a side effect of certain medications, or due to hormonal changes.

Photos A and B show clinical attachment loss.

FIGURE 7-23. Measurements to determine clinical attachment loss (level). A. First, the sulcus is probed (at 1 mm). B. Next, the level of the gingiva is determined with a positive number indicating gingival recession (at +1 mm from the dotted line, which is the CEJ). When the two numbers are added together, the amount of attachment loss is determined. In this case, the probing depth of 1 mm and the gingival level of + 1 (1 mm recession) result in an attachment loss of 2 mm.


Periodontists also make interproximal measurements of the gingival margin level that is a more challenging task. The severity of periodontal disease can therefore be accurately determined at the six sites around each tooth by measurements.


Bleeding on probing occurs when bacterial plaque affects the gingival sulcular epithelium, resulting in inflammation in the underlying connective tissue. Bleeding visible from the gingival margin after probing is an important indicator of inflammation (Figs. 7-24A and B and 7-10B and D).

Photos A and B show a clinical example of probe placement and bleeding on probing.

FIGURE 7-24. Clinical example of probe placement and bleeding on probing (BOP). A. Midlingual (midpalatal) probe placement on tooth #13 showing 3 mm sulcus depth. B. Mesial probe placement on tooth #13 probed into the lingual embrasure. Note a 5 mm pocket at the site, which shows BOP.


1. Technique to Document Bleeding on Probing

When bleeding is noted after probing several teeth, teeth that exhibit bleeding can be recorded at each probing site on the chart as a red dot above the probe depth. The percentage of sites that bleed can be calculated by dividing the number of bleeding sites by the number of total sites (where total sites equal the number of teeth present times six probe sites per tooth). Bleeding sites are charted in Figure 7-18, and a percentage has been calculated for four teeth.


A furcation is the branching point between roots on a multirooted tooth. In the absence of existing or previous periodontal disease, furcations cannot be clinically probed because they are filled in with bone and periodontal attachment. With advancing periodontal disease, however, attachment loss and bone loss may reach a furcation area resulting in a furcation involvement.28,29 Pockets that extend into the furcation create areas with difficult access for the dentist and dental hygienist to clean during regular office visits and are a real challenge for patients to reach and clean during their normal home care. Therefore, these areas of furcation involvement readily accumulate soft plaque deposits and mineralized calculus (seen on an extracted teeth in Fig. 7-25). These deposits frequently become impossible to remove and may provide a pathway for periodontal disease to continue to progress.

A photo shows calculus in the furcation area and root depression.

FIGURE 7-25. Calculus in the furcation area and root depressions. This extracted molar has mineralized deposits (calculus) in the furcation. Once disease progresses into the furcation area, access for removal by the dentist or dental hygienist becomes exceedingly difficult.


Initially, there may be an incipient (initial or beginning) furcation involvement. As disease progresses into the furcation (interradicular) area, attachment loss and bone loss will begin to progress horizontally between the roots. At that point, a furcation probe (such as a Nabor’s probe with a blunt end and curved design seen in Fig. 7-26B) can probe into a subgingival furcation area. It can be used to detect the concavity between roots (Fig. 7-26A). The first sign of detectable furcation involvement is termed grade I and can progress to a grade II involvement when the probe can hook the furcation roof (the part of the root forming the most coronal portion of the furcal area) as demonstrated in Figure 7-27A. In the most extreme circumstances, the furcation probe may actually extend from the furcation of one tooth aspect to the furcation on another tooth aspect. This is referred to as a through-and-through (grade III) furcation involvement (Fig. 7-27B). (A summary of the grades of furcation involvement is presented later in Table 7-4.)

TABLE 7-4 Notations for Three Categories of Furcation Involvement
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Sep 12, 2021 | Posted by in General Dentistry | Comments Off on Periodontal measurements: indicators of disease and conditions

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