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Recurrent Caries

What are Recurrent Caries?

Recurrent dental caries (tooth decay) around a gold crown.

Recurrent caries (tooth decay) at the margin of a gold crown. It is a potentially costly mistake to think that teeth which are covered with crowns cannot decay further.

Recurrent caries is tooth decay that occurs under existing dental restorations, such as fillings, crowns, or onlays. It may be caused by poor oral hygiene, or by development of a microscopic pathway for leakage (micro leakage) past the dental restoration.

Microleakage allows acids and bacteria access to areas of the tooth that are not accessible to toothbrush bristles or other oral hygiene aids.The possibility of microleakage is a strong motivator for replacement of questionable dental restorations, as well as complete removal of old restorative materials (for example, core buildups and bases) in a tooth that will be receiving a new crown or onlay.

How does the dentist diagnose Recurrent Caries?

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

Traditionally, dentists have detected tooth cavities in one of three ways: visual examination, tactile (by touch) examination; and X-ray images (radiographs).

Visual/Tactile Exam

A dental explorer on a tooth.

Dental explorers have been used for many years to detect early decay of teeth.

Some secondary cavities are obvious from looking. There may be yellow-brown to gray black discoloration with obvious softening or erosion of the tooth. Other cavities are discovered using a fine-tipped probe called an explorer (Figure 1). If an area of the tooth is softened by decay, the instrument will stick in the tooth.

X-ray images

Recurrent caries (secondary tooth decay) under a porcelain fused to metal crown.

The recurrent caries (secondary tooth decay) were detected by X-ray imaging. The arrow shows where decay has occurred under an existing porcelain fused to metal crown.

Decayed areas of teeth are visible as dark areas of the tooth on X-rays. Dentists use X-ray images to evaluate teeth for decay where visual/tactile examination is difficult or impossible, most notably between the teeth and under existing tooth restorations (Figure 2).

Laser Cavity Detection

Laser caries detection enables tooth decay to be diagnosed without using X-rays.

An artist’s rendering of the tip of a laser fluorescence caries detection meter emits a focused beam of 655nm wavelength light into the pits and fissures, causing fluorescence of decayed tooth structure. The amount of fluorescence is directly related to the size of the cavity. Healthy tooth enamel does not fluoresce.

A more recent and extremely sensitive diagnostic tool for determining whether there may be decay around restoration margins is the laser flourescence caries detection device, the tip of which is shown in the photograph below.

Healthy teeth do not fluoresce, and decayed teeth fluoresce in proportion to the amount of bacteria present in the tooth. This device measures the fluorescence pattern of teeth, and produces a reading on a meter which is recorded by the dentist.

How are Recurrent Caries treated?

Depending on the severity of the decay, restoring teeth with recurrent caries may involve fillings, inlays, onlays, veneers, or crowns. Decay that reaches the inner pulp of the tooth may require root canal therapy (endodontics) to eliminate the bacteria.

Decay that extends far below the gum line may require that the tooth be crown-lengthened before it is restored with a permanent restoration. Crown-lengthening is a surgical periodontal procedure. Severely decayed teeth, or those that would be costly and complex to restore (with questionable longevity) may require removal (simple tooth extractions or surgical tooth extractions).

If the tooth with recurrent decay is an anchor (abutment) tooth for a fixed bridge, the bridge may need to be replaced (although repairing bridge abutments is sometimes possible). If the bridge needs to be replaced, dental implants and removable dentures might be among the treatment options. If the affected tooth is an abutment tooth for a removable denture, the denture may need to be modified or replaced.

If the tooth with recurrent caries needs to be extracted, dental implants, fixed bridgework or removable dentures may be treatment options.

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

This page was last updated on March 6, 2018.
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