Transillumination and HDR Imaging for Proximal Caries Detection

Abstract

The purpose of this study was to develop an in vitro model for the validation of near-infrared transillumination (NIRT) for proximal caries detection, to enhance NIRT with high-dynamic-range imaging (HDRI), and to compare both methods, using micro-computed tomography (µCT) as a reference standard. Both proximal surfaces of 53 healthy or decayed permanent human teeth were examined using the Diagnocam (DC) (KaVo) and NIRT with HDRI (NIRT-HDRI). NIRT was combined with HDRI to improve the diagnostic performance by reducing under- and overexposed image areas. For NIRT-HDRI, an exposure series was captured and merged into a single HDR image. A classification was applied according to lesion depth. All surfaces were assessed twice by 2 trained examiners, and additionally with µCT for validation. The Kappa statistic was used to calculate inter-rater reliability and agreement between DC and NIRT-HDRI. Inter-rater reliability (weighted Kappa, wκ) showed very good agreement for the DC (0.90) and NIRT-HDRI (0.96). The overall agreement (wκ) was almost perfect (0.85). In the individual categories (0 to 4), the agreement (simple Kappa) ranged from almost perfect (category 4) to moderate (1 and 2) to substantial (categories 0 and 3). Sensitivity and specificity of sound surfaces, enamel, and dentin caries ranged from 0.57 to 0.99 and were similar for both methods in the different categories. NIRT-HDRI had a higher sensitivity for sound surfaces and enamel caries, as well as a higher specificity for dentin caries. Regarding the obtained images, HDRI allowed for the detection of caries within a greater range of luminance levels, resulting in a more detailed visualization of structures without under- or overexposure. However, HDRI this did not improve the diagnostics significantly. Distinguishing between a processed demineralized enamel and dentin lesions appears to be a problem specific to NIRT and cannot be balanced using HDRI.

In‐vitro validation of near‐infrared reflection for proximal caries detection

“…Images were captured using the VistaSoft software and were exported as Portable Network Graphics files. The proximal surfaces were evaluated following an existing classification of NIR transillumination according to the following criteria: sound (code 0); caries limited to enamel (code 1); caries with a single point of contact to the enamel–dentin junction (code 2); caries with extensive contact to the enamel–dentin junction (code 3); and caries visible in dentin (code 4) .…”

Validity of near‐infrared light transillumination for the assessment of proximal caries in permanent teeth

“…22 However, the significant heterogeneity in the study designs and the reference standards make it difficult to affirm that NIRLT could substitute X-rays in the auxiliary diagnosis of carious lesions. Furthermore, among these studies, an in-vitro model cannot completely simulate the intra-oral condition whereas some in-vivo experiments used visual inspection or cavities opening as a reference standard, [16][17][18][19][20][21][22][23][24][25] which cannot be used as a gold standard to accurately assess the sensitivity and specificity of DC. As Macey et al reported, high-quality studies for DC could still be useful becausetheir true effect on the dental examination does not currently seem to have been explored.…”

Molecular Fingerprint Imaging to Identify Dental Caries Using Raman Spectroscopy

“…This increase in fluorescence is mainly due to a bacterial photosensitive pigment present in caries tissue, but it could also be contributed by other factors related to oral hygiene. The FOTI/DIFOTI, NIRT, and LF methods have all been commercialized in dentistry, and their caries detection sensitivity/specificity is currently under examination [19]. Nowadays, the LF method is perhaps the most advanced radiation-free method available to enhance early identification of caries and to follow their development through regular successive examinations.…”