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Caries Detection

Aug. 1, 2001
New technology assists in the detection of caries.

New technology assists in the detection of caries.

by Karen Kaiser, RDH

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Since the emphasis in dental hygiene services focuses primarily on prevention, it is advantageous for hygienists to incorporate into their routine the most current chairside technologies that strive to achieve this goal. A laser unit is now available for the detection of tooth decay, identifying early dental disease. The unit complements traditional cavity-assessment knowledge. This early detection of decay enables conservative treatments that preserve tooth structure. One of the most promising and unique decay-detecting technologies recently approved by the FDA is the DIAGNOdent by KaVo America Corp.

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The DIAGNOdent is a laser, cavity-detecting device that illuminates caries lesions with defined light wavelengths. With the laser light handpiece illuminating the caries, the lesion will fluoresce and the degree of fluorescence can then be measured. Healthy teeth exhibit no fluorescence, resulting in a low reading (digital display on the unit). Specific light pulses are measured by the DIAGNOdent, giving the hygienist instant feedback on the health of a tooth. The digital readings and audible signals emitted by the unit allow both the hygienist and patient to begin co-diagnosis of suspicious tooth structure, even before an oral examination is performed by the dentist. This adjunct to traditional diagnostic methods enables the hygienist to complement the diagnosis and treatments recommended by the dentist, as well as confidently discuss treatment needs with patients.

The DIAGNOdent unit is compact, lightweight, user-friendly, and safe. The unit uses standard AA batteries, and there is no emission of radiation. Power optics reflects light energy through a handpiece and illuminates a glass tip.

The unit records digital readings from zero to 99. Generally, a value of 0-20 suggests no caries, although other clinical factors and diagnostic modalities factor into the diagnosis as well.

When conversing with patients, I explain that healthy teeth exhibit no audible sound. When the wand locates a change in the tooth's integrity, the unit will emit an audible signal. The higher the digital readout registers, a more elevated sound frequency can be noticed.

Patients are informed that sharp changes in the sound reveal areas of the tooth that may need attention. Because the laser can detect decay in the early stages, this breakthrough technology allows the dentist to perform conservative abrasion dentistry that arrests the spread of disease in a less invasive procedure.

The DIAGNOdent is best incorporated chairside after a thorough prophylaxis is completed. To attain the unit's truest readings, the tooth surfaces must be clean and dry. If the surfaces to be evaluated are not properly prepared, the readings may indicate a false positive. This is due to the inherent fluorescence of prophy paste or other debris.

To further ensure precise measurements, simple calibration of the unit is required weekly or when changing to a different tip. In the autoclavable cassette that houses the handpiece tips, a ceramic calibrating stone is included.

After calibrating the DIAGNOdent and preparing the tooth surfaces by drying, you then record the patient's zero base-line reading. This is done by locating an unrestored surface and recording the value of the middle third of the tooth. Once the base-line value is established, you may begin reading values of the teeth.

As you scan the tooth, you will have digital "peak" readings that will be displayed. This peak reading is accomplished by guiding the laser wand through the tooth fissures using passive contact. The patient listens to the "Geiger counter" tones that unveil suspicious surfaces as the hygienist scans the teeth. The DIAGNOdent allows quick, concise readings that require minimal chairside time from the hygienist.

The best features about the DIAGNOdent are that it is predictable and the results are repeatable. The benefit for the hygienist is that if a demineralized tooth has a low reading, you can confidently record that value. At future recare visits, new readings can be obtained, allowing the hygienist to monitor a tooth over a period of time. When a low value (below 20) is assigned to a tooth surface, I routinely discuss the benefits of using topical fluoride. At future recare visits, I obtain a new reading from the DIAGNOdent and see if remineralization therapy was effective for this patient.

Another beneficial use of the unit is to employ it prior to sealant placement. Although the standard explorer is the most notable detection method, it is limited when evaluating for fissure decay. With the laser cavity detection, "drop"-shaped fissures and paltry access points are revealed. Using the laser approach will prevent the hygienist from placing sealant material over decay, even when the outer tooth surface appears intact.

In addition, one of the arduous challenges of detection has always been differentiating between occlusal stain and decay. With the DIAGNOdent unit, this distinction is easily discerned.

The DIAGNOdent also works well with apprehensive children. A sharp explorer can be intimidating. I have found the laser unit to be patient-friendly and cause far less anxiety in both my young and older patients.

The uniqueness of the DIAGNOdent and the early decay detection that it provides makes this new technology a welcome addition to your diagnostic hygiene armamentarium. More information can be obtained by calling KaVo at (888) 528-6872 or visiting the company's Web site at

Karen Kaiser, RDH, has worked in private practices in both Missouri and Illinois. She can be contacted at [email protected].