Browsing by Author "Han, S"

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    ItemOpen Access
    Single board computer and adapted 3D-printed case-based low cost and compact optical coherence tomography
    (SPIE, 2025) Seong, D; Han, S; Kim, Y; Hong, J; Wijhesinghe, R. E; Jeon, M; Kim, J
    Optical coherence tomography (OCT) is a non-invasive, label-free imaging method based on high-resolution interferometric optics that allows real-time visualization of morphological structures and depth-resolved images. The high cost of most commercially available OCT systems limits their widespread use, especially in resource-poor settings. Miniaturization of OCT devices therefore reduces not only size but also cost and has the potential to open new markets for this technology. In this study, we developed a small, portable 3D printed OCT system (SBC-OCT) based on a single-board computer. To reduce the cost to configure the system, the whole case of SBC-OCT is made with 3D-printed architecture. Using an area camera to avoid thermally induced alignment distortions in the spectrometer during system operation, the spectrometer is temperature insensitive, requires no hardware changes or additional components, and requires minimal computational effort. An applied automatic signal correction method was developed. The smaller size, lighter weight, and lower cost of SBC-OCT highlight its significant relevance in medical, industrial, and security applications, showcasing its potential for broad adoption.
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    PublicationOpen Access
    Three-Dimensional Assessment of Dental Enamel Microcrack Progression After Orthodontic Bracket Debonding Using Optical Coherence Tomography
    (Multidisciplinary Digital Publishing Institute (MDPI), 2025-01) Saleah, S.A; Hamdan, A.H; Seong, D; Ravichandran, N. K; Wijesinghe, R.E; Han, S; Kim, J; Jeon, M; Park, H. S
    The current study aimed to quantify the length progression of enamel microcracks (EMCs) after debonding metal and ceramic brackets, implementing OCT as a diagnostic tool. The secondary objectives included a three-dimensional assessment of EMC width and depth and the formation of new EMCs. OCT imaging was performed on 16 extracted human premolars before bonding and after debonding. Debonding was conducted with a universal Instron machine, with ARI values recorded. Additionally, 2D and 3D OCT images were employed to detect EMC formation and progression. Enface images quantified the length, width, and number of EMCs, and the length and width were analyzed using Image J (1.54f) and MATLAB (R2014b), respectively. Sagittal cross-sectional images were used for EMC depth analysis. A paired t-test showed significant differences in the length, width, and number of EMCs after debonding (p-value < 0.05), while the Wilcoxon non-parametric test indicated significant EMC depth changes (p-value < 0.05). No significant results were identified for the EMC number in ceramic brackets and EMC depth in metal brackets. Three-dimensional OCT imaging monitored existing EMCs at higher risk of progression and detected new EMCs following orthodontic bracket debonding. This study provides novel insights into EMC progression regarding the length, width, depth, and number after debonding.