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Poorly Contoured Dental Restorations / Dental Overhang

What are Poorly Contoured Dental Restorations?

An example of poorly contoured dental restorations: Dental x-ray of overcontoured crown on tooth with plaque trap caused perio pocket.

Figure 1a: Here, a crown was placed over an overhanging silver filling without removing the overhang (1). The result is the same—difficulty cleaning under the ledge can lead to secondary (recurrent) tooth decay, and damage to the gums and bone (2) adjacent to the poorly contoured dental restoration.

Dental restorations (fillings, inlays, crowns, etc.) are ideally made to blend smoothly with the contours of the natural tooth being restored. Ideally, the margins should close down tightly against the tooth, providing a hermetic seal against bacterial invasion.

If the restoration is built too large, or the margins overhang the edge of the tooth, food and bacterial plaque can accumulate along the margins, leading to inflammation and tooth decay (caries). Plaque accumulation in such areas can produce a bad taste and bad breath (halitosis).

Poorly contoured dental restorations do not always reflect a low skill level or lack of attention to details. In some situations, establishing ideal tooth contours is complicated by poor visibility, decay that extends well below the gum level, restricted ability of a patient to open their mouth adequately, and other factors.

Dental x-ray shows overcontoured silver filling in tooth causing periodontal pocket.

Figure 1b: A silver filling with a large overhang. Arrows show where an overhanging silver filling (1) has led to early bone loss (2). This is because food and bacterial plaque accumulate under the ledge, and are difficult or impossible for the patient to remove.

Sometimes, in an effort to be conservative, a well-meaning dentist may try to avoid crown-lengthening a tooth (a surgical periodontal procedure), and the restoration contours may be compromised as a result. However, if the tooth is to be maintained long term, restoring its ideal contours is typically recommended. Otherwise, even a well motivated patient may not be able to prevent problems from arising around the tooth over time.

How does the dentist diagnose Poorly Contoured Dental Restorations?

Note: ToothIQ.com contains general information. Only a dentist can properly diagnose your specific condition.

The significance of poorly contoured dental restorations depends in part on how well the patient can adapt to cleaning around them, and how the patient’s tissues respond to the presence of a plaque trap. Some patients have good dental health in general, but may have localized inflammation secondary to the poorly contoured restoration.

This situation is diagnosed by observation of localized redness and possible tenderness; bleeding on gentle probing; presence of abnormally high periodontal pocket measurements (4 millimeters or greater); presence of accumulated food/plaque/calculus deposits of which the patient may or may not be aware. X-ray images verify the presence of an overhang or open margin—a gap between the restoration and tooth, which are not easily cleaned by the patient and eventually become populated with enough bacteria to cause tooth decay or periodontal damage.

Often, the patient will notice that floss catches, shreds, or unravels at the interface of an irregular dental restoration.

How are Poorly Contoured Dental Restorations treated?

If the restoration cannot be recontoured ideally, replacement within an appropriate dental restoration will typically be recommended. The urgency for doing so depends on how well the patient can maintain hygiene at the affected site, and the health status of the tooth and periodontal tissues.

Recontouring of the restoration is done with specialized shaping instruments, and is usually done only if it is possible for the dentist to clinically verify that a gap between the overhanging restoration and the tooth hasn’t been created, and that the problem with the restoration has been solved.

More commonly, the replacement of the restoration will be recommended. If so, it may or may not be replaceable by another restoration of the same kind. Sometimes additional problems are identified when the existing restoration is removed that can change the treatment plan from one type (e.g. filling) to another (e.g. crown). Often, additional procedures will be recommended (e.g. crown lengthening surgery) before replacing the restoration, so that problems with the tooth can be clearly visualized, and the patient can see to keep it clean.

Diagnostic photographs and X-rays (radiographs) are useful in diagnosing the condition, and in communicating the significance of the problem and urgency for treatment to the patient.

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Author: Thomas J. Greany, D.D.S. / Editor: Ken Lambrecht

This page was last updated on .

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