Background: Caries detection in school oral examinations insufficient accuracy. Objective: To evaluate advantages of introducing quantitative light-induced fluorescence-digital (QLF-D) in school oral examinations. Methods: Experiment No. 1. Early demineralized lesions in the upper and lower incisors and canines were visually inspected by three dentists and by QLF-D. The numbers of tooth planes with early demineralized lesions were compared between the methods. Experiment No. 2. Approximal demineralized lesions in molars were assessed by visual inspection, x-ray imaging, and QLF-D. The numbers of tooth planes with demineralized lesions were compared among the methods. Experiment No. 3. Plaque distribution was evaluated by QLF-D and a traditional staining method. The ratio of the diameter of plaque to tooth crown in the tooth axis direction in each method was calculated. The results were evaluated by Pearson’s correlation coefficient analysis and Bland-Altman plot. Results: Experiment No. 1. The three dentists found 0.67 tooth planes on average. QLF-D found 22 tooth planes with early demineralized lesions in the same samples. Experiment No. 2. Fourteen approximal tooth planes of molars were found to have demineralized lesions by x-ray imaging. QLF-D detected 71.4% of the tooth planes out of the 14, whereas visual inspection found 7.1%. Experiment No. 3. The Pearson’s correlation coefficient for the evaluations of plaque distribution between the QLF-D and traditional staining methods was 0.77 (P < 0.001). No statistically significant systematic error was found through the Bland-Altman Plot analysis. Conclusion: The results support introduction of QLF-D for use in school dental examinations.
Objective, safe, and easy-to-use means of evaluating demineralized lesions have not been available outside of dental offices, so dental checkups at schools must primarily rely on visual inspection in Japan. However, dentists have to perform visual inspections of numerous students with insufficient time and light sources. Consequently, the accuracy of school dental checkups in Japan depend on the skill of individual dentist. When there is an obvious cavity on the tooth surface, it can be detected easily, but if the demineralized lesion is hidden in the approximal region that cannot be seen directly or is in its early stage, it cannot be found through visual inspection in such poor surroundings [
This study was carried out from May 2014 to March 2016.
Three dentists who had professional backgrounds of >3 years performed visual inspections. They inspected early demineralized lesions in incisors and canines in 10 child patients who visited our clinic for regular dental checkup. The child patients were six boys and four girls whose age ranged from 6 to 14 years. In this visual inspection, early demineralized lesions were defined as demineralized lesions that had a shade abnormality, but did not have any cavities. After the visual inspection, images of the teeth were taken by QLF-D under the following conditions: shutter speed of 1/60 second, aperture value of 5.6, ISO speed of 1600 [
Demineralized lesions of approximal planes in upper and lower molars excluding distal planes in posterior end molars (48 surfaces) were visually inspected by three dentists who had professional backgrounds of >3 years. Following the visual inspection, the same regions were analyzed by QLF-D under the same conditions as in the detection of early demineralized lesion in incisors and canines. Then, dental radiographs were taken and interpreted. In dental radiographs, an early demineralized lesion was defined as a radiolucent lesion within the enamel (C1) because dental caries is recognized as a radiolucency in a radiograph in daily clinical practice when the lesion becomes C1 or severer [
Five adult males without past and present systemic illness history whose ages ranged from 27 to 29 years participated in the study as test subjects. The subjects were asked to forego teeth brushing for 60 hours. At 60-hours, images of the upper and lower central incisors, lateral incisors, and canines were taken by QLF-D under the following conditions: shutter speed of 1/60 second, aperture value of 5.6, ISO speed of 1600 [
(Unit: Tooth Planes) | ||
---|---|---|
Patients | Visual Inspection | QLF-D |
A | 0 | 3 |
B | 0 | 0 |
C | 0 | 8 |
D | 0 | 3 |
E | 0.67 | 4 |
F | 0 | 2 |
G | 0 | 0 |
H | 0 | 1 |
I | 0 | 1 |
J | 0 | 0 |
detected through visual inspection or QLF-D. Two of the three dentists who had professional backgrounds of >3 years found a tooth plane with an early demineralized lesion in only one participating child through visual inspection. On the other hand, QLF-D found early demineralized lesions in seven participating children out of 10. QLF-D detected four tooth planes with early demineralized lesions in a child who had been determined to have had an average number of 0.67 tooth planes with early demineralized lesions through the visual inspection.
Results of Examination | Tooth Planes |
---|---|
Visual Inspection (−), QLF-D (−), X-ray (−) | 13 |
Visual Inspection (+), QLF-D (+), X-ray (+) | 0 |
Visual Inspection (+), QLF-D (−), X-ray (−) | 10 |
Visual Inspection (−), QLF-D (+), X-ray (−) | 10 |
Visual Inspection (−), QLF-D (-), X-ray (+) | 4 |
Visual Inspection (−), QLF-D (+), X-ray (+) | 9 |
Visual Inspection (+), QLF-D (−), X-ray (+) | 1 |
Visual Inspection (+), QLF-D (+), X-ray (−) | 1 |
QLF-D detected nine out of 14 tooth planes that had demineralized lesions in which the lesion was found by radiography. On the other hand, no tooth surface with a demineralized lesion was found through visual inspection out of the 14 tooth planes. Of the tooth planes in which lesions were found through visual inspection, 7.1% were diagnosed as being sound by QLF-D. In the same way, 7.1% of the tooth planes in which demineralized lesions were found in radiography were found to have demineralized lesions through visual inspection, which meant that 92.9% of the approximal tooth planes with demineralized lesions were missed in the visual inspection.
Demineralized lesions were found in 25 tooth planes through radiography or QLF-D. QLF-D detected demineralized lesions in 10 of the 25 tooth planes, whereas radiography found four tooth planes with demineralized lesions. Both QLF-D and radiography detected the lesions in nine out of the 25 tooth planes.
When a tooth is illuminated with blue light (wavelength of 405 nm), the tooth emits fluorescence especially at the enamel-dentin junction. This fluorescence loses energy, increases in wavelength, and travels through enamel. QLF-D consists of a single-lens reflex camera equipped with a blue and white light-emitting diode (LED) and personal computer in which software for analysis is installed (
to measure the volume of fluorescence emitted by the enamel in response to the blue light from the LED. The volume of fluorescence emitted from sound enamel is defined as F1. The fluorescent light that travels through a demineralized lesion is reduced by diffuse reflection, which is defined as F2 (
As shown in
missed in regular school checkups, which are performed at schools with insufficient light sources and without dental chairs. Gimenez et al. [
Radiography is widely used in determining the prognosis of dental caries. Thus, it was required that QLF-D had at least the same caries sensing capability as that of radiography in this study. So, the accuracies of visual inspection and QLF-D were evaluated in tooth planes in which demineralized lesions were found by radiography. Visual inspection detected the demineralized lesions in 7.1% out of the tooth planes, whereas QLF-D detected the lesions in 64.3% of them. The results suggested that the combined application of QLF-D and visual inspection was more effective in approximal caries detection in molars. Ko HY et al. [
Since it was reported that there was a high correlation between QLF-D and pathological examination of enamel in caries detection [
In Japan, dentists visit schools and perform oral checkups regularly; they have to make a diagnosis in approximately 30 seconds per student with a poor light source, otherwise they cannot accomplish their assignment within the schedule. If dentists introduce QLF-D for use in oral checkups at schools, they can bring the images home, analyze them objectively without a tight time limit, and give notice later as done for hematological examination. QLF-D detects carious lesions in the very early stage, at which point they should be controlled instead of being drilled and filled. Jallad et al. (2015) [
Although QLF-D was originally developed for evaluation of demineralized lesions in the early stages, it is also known that porphyrin in plaque also reflects fluorescence when it is illuminated with blue light by QLF-D [
In
The results of the Pearson’s correlation coefficient analysis and Bland-Altman plot suggested that there was no statistical difference in plaque detection between the staining method and QLF-D.
In Japan, dentists have to see approximately two students per minute with poor light sources to complete their duties in time when they provide oral checkups at schools. The oral checkup is usually performed only by visual inspection. As a result, it has been said that the accuracy of school oral checkups is insufficient. In this study, demineralized lesions and plaque adhesion were evaluated by QLF-D in available surroundings in school dental checkups, and the findings indicated that QLF-D was effective in such surroundings. If QLF-D is introduced for use in school oral checkups, the dentists can obtain a sufficient light source by using the flash of the single-lens reflex camera and will only have to take photographs at school. They can then take the images back to their offices and make a diagnosis objectively without a time constraint. QLF-D can detect demineralized lesions at the very early stage, so dentists can provide proper advice to school children through oral checkups before the lesions deteriorate further.
One slight disadvantage of QLF-D is that dentists have to have sufficient skill to take proper images, but the photographic process is mostly automated.
1) Detection of demineralized lesions at the very early stage through visual inspection was very difficult.
2) Detection of demineralized lesions in the approximal plane through visual inspection was also difficult.
3) QLF-D was a very effective means of detecting both an early demineralized lesion and a demineralized lesion in the approximal tooth plane.
4) QLF-D detected an early demineralized lesion that was not found by visual inspection or radiography. Detection by QLF-D of an early demineralized lesion could be useful for encouraging children to receive daily habits and oral hygiene instruction.
5) QLF-D showed good accuracy for plaque detection that was statistically equal to that of a traditional staining method.
6) QLF-D was found to be an effective means of detecting plaque and demineralized lesions in school oral checkups.
The authors declare no conflicts of interest regarding the publication of this paper.
Watanabe, K., Sasabe, T., Nakamura, A., Eda, K., Tanase, K., Ikeda, H., Ohata, N., Minohara, Y., Maki, K. and Watanabe, S. (2018) Advantage of Introducing Quantitative Light-Induced Fluorescence in School Dental Checkups. Health, 10, 1095-1106. https://doi.org/10.4236/health.2018.108083