Validation of quantitative light-induced fluorescence-digital (QLF-D) for the detection of approximal caries in vitro

Abstract

Validation of quantitative light-induced fluorescence-digital (QLF-D) for the detection of approximal caries in vitroHae Youn KoDepartment of DentistryThe Graduate School, Yonsei University(Directed by Professor Baek Il Kim)As it was realized that dental caries process is dependent on the balance between pathological factors and protective factors, and that caries progresses when the pathological factors predominate while it can be arrested or reversed when the protective factors predominate, the treatment principles for caries lesions gradually shifted towards preventive treatment of enamel lesions. However, in order to implement preventive therapy, caries lesions need to be detected at their early stage. However, early detection of caries can be difficult, especially approximal caries, due to their anatomical position. Therefore, visual examination alone is likely to underestimate the number of approximal carious lesions. Radiographic examination is another common method for detection of approximal lesions, yet it has been known that radiographic examination often detects caries lesions at advanced stage, beyond the scope of remineralization interventions. Furthermore, the use of ionizing radiation, which exposes patients to risk, leads into consideration of alternative methods for detection of approximal lesions. These disadvantages of the conventional detection methods have led to a great interest in development of new devices for accurate detection of approximal lesions.One of the devices is Quantitative Light induced Fluorescence-digital BiluminatorTM (QLF-D). This device is able to quantify mineral loss using its excitation light of 405 nm blue light on enamel. Other than the quantitative analysis method, a qualitative analysis method of QLF has been reported as QLF-I. The present study was conducted: firstly, to assess the ability of the QLF-D to distinguish between different stages of approximal caries lesion development by comparing the qualitative analysis method (QLF-DI) and the quantitative analysis method (QLF-DF) with histology examination; secondly, to compare the validity with other various detection methods such as ICDAS II and digital radiography; and finally, to determine the relationships among ICDAS II, QLF-DI, and QLF-DF using these simulation pairs.A total of 100 permanent molar and premolar teeth were selected from a pool of extracted permanent human teeth from Yonsei University, with ethical approval from the Institutional Review Board for Clinical Research in Yonsei dental hospital (IRB 14-0067). Pairs were formed of the extracted teeth with their marginal ridges in contact to simulate the oral relationship, and the pairs were examined using ICDAS II, digital radiography, and QLF-D. All the examinations were performed by one calibrated dentist, and the recordings for all the examinations were repeated with a 7-day intermission among the different modalities. After completion of all the assessments, all teeth were prepared for histological assessment.