Mr. Mihai-Stefan M. Duma Profile

Mihai-Stefan M. Duma

at Univ. Politehnica Timisoara

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Author

Publications (2)

Proceedings Article | 11 August 2023 Poster + Paper

Optical coherence tomography and microbiology evaluations of different methods for manufacturing dental prostheses

Mihai-Stefan Duma, Denisa Drimbe, Ralph-Alexandru Erdelyi, Virgil-Florin Duma, Ioana Moldovan, Anne-Marie Heredea, Elena Rodica Heredea, Meda-Lavinia Negrutiu, Daniela Maria Pop, Mihai Rominu, Dan Ioan Stoia, Cosmin Sinescu

Proceedings Volume 12622, 1262212 (2023) https://doi.org/10.1117/12.2673297

KEYWORDS: Optical coherence tomography, Manufacturing, Biofilms, Microbiology, Biological samples, Polymers, Glasses, Tissues, Gold, Coherence imaging

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Oral hygiene is one of the key measures recommended by WHO. The aim of this work is to assess the efficiency of different methods and materials for manufacturing dental prostheses regarding the biofilm that is formed both on the dental prosthesis and on its surrounding tissue. Several such prostheses are considered, manufactured using three techniques: (i) conventional, (ii) milling, and (iii) printing. Two assessment methods are utilized for the biofilm characterization: microbiology evaluations and Optical Coherence Tomography (OCT) imaging. The latter involves an in-house Swept Source (SS) OCT system operating at 1300 nm, with a 15 μm axial resolution. In the sampling method, cells are detached from the surface of the gingival mucosa and dental prostheses by scraping (like in the Babes-Papanicolau cytological examination for the evaluation of the cervical mucosa). After sampling they are placed on glass slides for examination, forming what is called smears. The presence of physiological or pathogenic microflora can be identified on these smears, as well as the local effect, which translates into the induction of an immune response. The smears are stained by using both APT-Drăgan and Babeș-Papanicolau methods. The advantage of the cytological examination consists in its efficiency, safety, speed, simplicity, and in the fact that it is a non-invasive medical procedure. Smears obtained from the surface of the gingival mucosa and dental prostheses are examined under an optical microscope. Cellularity and bacterial flora are evaluated, comparing them on different types of prostheses, depending on the cellular and inflammatory elements on the mucosal surface. The cytodiagnostic identified cellular lesions of an inflammatory, allergic, and tumor nature. On the other hand, the study demonstrated that OCT can quantitatively evaluate the width of the biofilm (i.e., of the smear in this ex vivo investigation). The two types of techniques can thus complement each other. Conclusions are drawn regarding the efficiency of each of the considered manufacturing methods and materials.

Proceedings Article | 9 May 2018 Paper

Testing of optical choppers using laser lines

Mihai Stefan Duma, Virgil-Florin Duma

Proceedings Volume 10680, 106802A (2018) https://doi.org/10.1117/12.2306556

KEYWORDS: Optical choppers, Manufacturing, Laser applications, Optical testing, Laser optics, Radiometry, Signal attenuation, Laser drilling, Laser cutting, Telescopes

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