Fluorescence devices for the detection of dental caries

Richard Macey, Tanya Walsh, Philip Riley, Anne-Marie Glenny, Helen V. Worthington, Patrick A. Fee, Jan E. Clarkson, David Ricketts

Why is it important to improve dental caries (tooth decay) detection?

Dentists often aim to identify tooth decay that has already advanced to a level which needs a filling. If dentists were able to find tooth decay when it has only affected the outer layer of the tooth then it is possible to stop the decay from spreading any further and prevent the need for fillings. It is also important to avoid a false-positive result, when treatment may be provided when caries is absent.

What is the aim of this review?

This Cochrane Review aimed to find out how accurate fluorescence devices (non-invasive devices that shine a light on the surface of the tooth) are for detecting and diagnosing early tooth decay as part of the dental 'check-up' for children and adults who visit their general dentist. Researchers included 133 studies to answer this question.

What was studied in the review?

There are three different types of fluorescence device that use different types of light which we grouped as red, blue, and green fluorescence. Each device reflects more or less light depending on the amount of tooth decay, and this is measured by the device to give a score which indicates whether there is tooth decay and how severe the decay is. We studied decay on the occlusal surfaces (biting surfaces of the back teeth), the proximal surfaces (tooth surfaces that are next to each other), and the smooth surfaces.

What are the main results of the review?

The review included 133 relevant studies but 55 of these did not provide data in a format that we could use for analysis, so 79 studies with a total of 21,283 teeth were included in the analysis. Some of these studies reported on more than one type of fluorescence device, this gave us 114 sets of data. The results of these studies indicate that, in theory, if the fluorescence devices were to be used by a dentist for a routine dental examination in a group of 1000 tooth sites or surfaces, of which 574 (57%) have early tooth decay:

•         an estimated 494 will have a fluorescence device result indicating tooth decay, and of these, 95 (19%) will not have tooth decay (false positive - incorrect diagnosis);

•         of the 506 tooth sites or surfaces with a result indicating that tooth decay is not present, 171 (34%) will have early tooth decay (false negative - incorrect diagnosis).

Please see oralhealth.cochrane.org/fluorescence-devices-results.

We found no evidence that the devices that used different types of light (red, blue, or green fluorescence) differed in their accuracy. 

How reliable are the results of the studies in this review?

We only included studies that assessed healthy teeth or those that were thought to have early tooth decay. This is because teeth with deep tooth decay would be easier to detect. However, there were some problems with how the studies were carried out. This may have resulted in the fluorescence-based devices appearing more accurate than they are. We judged the certainty of the evidence as low due to how the studies selected their participants, the large number of studies that were carried out in a laboratory setting on extracted teeth, and the variation in results reported.

Who do the results of this review apply to?

Studies included in the review were carried out in Brazil, Europe, the Middle East, Asia, North America, and Australia. A large number of studies used extracted teeth. Others were completed in dental hospitals, general dental practices, or schools. Studies were from the years 1998 and 2019.

What are the implications of this review?

Because of the wide variation in performance that cannot be easily explained the interpretation of results is difficult. The proportion of cases missed or incorrectly diagnosed as evidence of caries is relatively high. Important information was missing from many of the included studies. Any future studies should be carried out in a clinical setting, and look at the potential of fluorescence devices to be used alongside other devices.

How up-to-date is this review?

The review authors searched for and used studies published up to 30 May 2019.

Read the full review.

Macey  R, Walsh  T, Riley  P, Glenny  A-M, Worthington  HV, Fee  PA, Clarkson  JE, Ricketts  D. Fluorescence devices for the detection of dental caries. Cochrane Database of Systematic Reviews 2020, Issue 12. Art. No.: CD013811. DOI: 10.1002/14651858.CD013811.