It is always exciting to share new or improved dental technologies and techniques. One of these evolving developments is related to caries visualization and diagnosis. The use of fluorescence to diagnose and treat caries in a minimally invasive way is not new, but more options using this technology are coming to market. It is providing more options to help clinicians save tooth structure and improve long-term outcomes.

Before we look at where this technology is going, let's look at where we are now. There are two steps of caries formation: demineralization and bacterial contamination. Current methods of detecting caries include explorers, which can damage the tooth and exacerbate the carious lesion, and radiography, which supports decision-making by assisting with visualization. Neither of these approaches provides dentists with information on the degree of demineralization or whether bacterial contamination is present, and both can lead to removing more tooth structure than may be necessary.

The History of Fluorescence in Dentistry

Some of you may have already heard about the use of fluorescence to diagnose and treat caries differentially. Research has been conducted on the accuracy of different types of light transmission for caries visualization, diagnosis, and differentiation of lesions for several years, with fluorescence studied since the early 1990s.

In the 90s and early 2000s, much research focused on using nitrogen lasers to fluoresce teeth and diagnose caries. Bacterial contamination, with different wavelengths, was studied to determine the most effective for differentiating the degree of caries and type of bacterial growth. Now, non-ionizing light sources such as ultraviolet and infrared light are more commonly being studied and marketed.

According to the Oxford dictionary, fluorescence is the “visible or invisible radiation emitted by certain substances as a result of incident radiation of a shorter wavelength such as X-rays or ultraviolet light. It is the property of absorbing a short wavelength of light and emitting light of longer wavelength.” Depending on the wavelength of light emitted; the target substance will exhibit autofluorescence, which is the “fluorescence of naturally occurring substances that is present in most plant and animal tissues.” While this technology is available in dentistry, it is not commonly used — but you may hear more about it in the future.

The Benefits of Fluorescence in Caries Visualization

Fluorescence for caries diagnosis provides clinicians with a less invasive approach to treatment by visually allowing us to identify where disease is present and preserve as much of the natural tooth as possible. By using a source such as ultraviolet light to excite and transmit light to the tooth surface and then viewing the tooth's corresponding type and degree of autofluorescence, a clinician can make a well-informed diagnosis. The type and degree of fluorescence can be used to identify demineralization and differentiate the diagnosis.

For caries visualization and diagnosis, the enamel and dentin fluoresce at different peaks, ranging from 350 to 450 nm1. The color variation of the autofluorescence, which varies from green to orange to red in affected teeth, can be used to determine the level of decay or demineralization and the presence or absence of bacteria. By using magnification via Loupes microscope and visualizing the location and type of autofluorescence, you can remove only the tooth anatomy affected by caries, reducing the incidence of unwanted complications, including the removal of healthy tooth structure, increased tooth sensitivity, and compromised tooth vitality.

As with any other type of dental tool or equipment, the positivity of results using fluorescence depends on the clinician, their understanding of how the technology works, and how they apply it. This is a rapidly evolving field, with new options for caries visualization and diagnosis continuing to be introduced to the market.

Robert Winter, D.D.S., is a member of Spear Resident Faculty.