Purpose
The Inspektor™ Pro system utilizing Quantitative-Light Induced Fluorescence (QLF™) is a feasible system for monitoring early carious lesions, remineralization, and demineralization in a clinical setting. This new technology allows clinicians to objectively monitor lesions before cavitation as well as the effectiveness of recommended preventive treatments.
Abstract
In the late 80’s, light refraction techniques were developed to increase the contrast of sound enamel vs. demineralized enamel. It was noted that different wavelengths (colors) of light would create different images of the tooth. Wavelengths in the blue spectrum made it easier to see demineralization. It was determined that blue light (peak 405 nm) viewed through a yellow filter (cutoff 520 nm) created the best contrast enhancement of demineralized surfaces.
This color scheme combined with a CCD camera could take images of lesions and proved to be much more sensitive than visual examination. Research has shown that 2-10 times more lesions can be detected with Inspektor Pro than with the naked eye, depending upon the surfaces that are being viewed (smooth or occlusal).
The addition of software and computers to the technology made detecting decay even easier. The new Inspektor Pro software contains image recognition software that remembers what a tooth surface from a previous visit looks like. When the camera lens is placed over the same tooth on subsequent visits and nearly identical positioning to the first image taken, the computer then captures images automatically and compares them to the first image. The clinician can then compare and contrast the images to determine if the lesion has remineralized or demineralized. This new feature created a way of tracking demineralization and remineralization over time in a form of time lapse photography.
Inspektor Pro can now offer objective proof that remineralization and demineralization are taking place. Recent research by Kambara et al. in Osaka Japan has shown the remineralization difference in tooth enamel created from 1100-ppm NaF dentifrice after only three months.
The Inspektor Pro also has potential to improve the quality of restorations and detect faulty existing restorations. For use during a restorative procedure, the clinician will first diagnose the cavitation. Then excavation of the lesion is begun. Once the excavation has continued to a point that appears to be complete with the naked eye, the Inspektor Pro can be used to determine that the decayed material has been removed. Figure 1 shows a tooth in preparation that still needs further preparation.
For secondary decay detection, the Inspektor Pro offers a new dimension to ensure sound margins. The following image (figure 2) is of a tooth that has an amalgam in place. The patient in this case was complaining that the tooth was experiencing sensitivity. This amalgam is showing red fluorescence around its edge on a few sides, as well as shaded areas indicating that decay is present. This decay is shown as a clouded area on screen. The sound edges of the amalgam appear as hard lines with very little shaded or ‘smeared’ appearances. This restoration was replaced without the use of Inspektor Pro and looks sound to the naked eye. However, when a follow up image of the new composite is taken with Inspektor Pro, we see areas in the margin that may still be faulty.
Inspektor Pro sees this blackout zone (on a radiograph) from the surface and gives you a clean view of what is happening without waiting for the decay to pass deeper than the restoration.
Inspektor Pro allows an image to be taken of the tooth and shown to a patient. In clear and concise terms, easy enough for any patient to understand the tooth is displayed. For added benefit, if there are areas that are difficult to see, the computer can analyze these images and highlight the issues for the patient. This education tool is powerful.
Conclusions
QLF technology that powers the Inspektor Pro system can provide a very early caries detection system for sound and restored surfaces. This new technology shows promise to be one of the most sensitive systems available to the practicing dentist, and can help detect caries when minimally invasive or non invasive therapies can be recommended.