Quantitative light-induced fluorescence as a potential tool for detection of enamel chemical composition

Joo Young Lee, Hyo Jung Kim, Eun Song Lee, Elbert de Josselin de Jong, Hoi In Jung, Baek Il Kim

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6 Citations (Scopus)


Background: Little is known about how the chemical composition of enamel affects the optical properties of teeth, but advances in technology allow this to be studied using white-light and fluorescent images. This study aimed to identify the variation in enamel chemical composition that may affect tooth optical properties, such as tooth color and autofluorescence. Methods: Sixty-one specimens of extracted human molars were prepared. Raman spectrometry was used to assess chemical composition of enamel, and tooth color, and autofluorescence from enamel were evaluated by quantitative light-induced fluorescence (QLF) images. Pearson correlation and multiple linear regression analyses were used. Results: Enamel fluorescence was related to enamel composition rather than tooth color. The b* value from the fluorescence image had a moderate correlation with crystallinity (full-width at half-maximum: r = −0.433, p < 0.001) and laser-induced fluorescence intensity (r = 0.450, p < 0.001) from Raman spectroscopy. In multiple linear regression analysis, the chemical composition of the tooth had a significant effect on the b* value from the fluorescent image (R2 = 0.433, p < 0.001). In contrast, tooth color values (L*, a*, and b*) were not correlated with chemical composition. Conclusions: The present study revealed that enamel autofluorescence in QLF was related to chemical composition of the enamel, particularly the inorganic‒organic interface. While enamel chemical composition can be detected only in a laboratory environment, enamel fluorescence by QLF may enable estimation in a dental clinic, which has implications for the field of tooth bleaching or esthetic restorative materials.

Original languageEnglish
Article number102054
JournalPhotodiagnosis and Photodynamic Therapy
Publication statusPublished - 2020 Dec

Bibliographical note

Funding Information:
Inspektor Research Systems BV provided the salary for author EdJdJ, but did not have any additional role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript. EdJdJ’s involvement in this research was under the auspices of his status as adjunct professor at Yonsei University College of Dentistry supported by BK21 PLUS Project. The specific role of EdJdJ was to provide his expertise regarding the fluorescence technology. This does not alter the author’s adherence to the policies of Photodiagnosis and Photodynamic Therapy on sharing data and materials. EdJdJ holds several patents with respect to QLF technology. The remaining authors declared no conflicts of interest.

Publisher Copyright:
© 2020 Elsevier B.V.

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Oncology
  • Dermatology
  • Pharmacology (medical)


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