Abstract
Optical coherence tomography (OCT) is a novel, non-invasive imaging modality, applied in everyday practice in opthalmology. It enables cross-sectional real-time imaging of different tissue microstructures in situ. The optical biopsy, provided by OCT gives further microstructural information about oral soft and hard tissues and different deposits adhered to these surfaces. The aim of this study was to evaluate the diagnostic value of OCT for chronic diseases of soft and hard tissues of the oral cavity. Microfractures of dental tissues and biofilm developed on soft and hard tissues of the oral cavity were examined.
Methods: The study took place in the Departments of Restorative Dentistry and Opthalmology at the University of Debrecen between December 2015 and April 2016. It was approved by the University of Debrecen ethics committee and all patients who took part gave their written consent. Forty two examinations were performed on 14 patients, with 3 types of OCT devices on oral soft and hard tissues. OCT devices utilize the different ability of biological tissues to absorb and reflect light. Biofilm which adhered to dental surfaces and gingiva was examined with Time- Domain (TD) OCT (Zeiss Stratus OCT, Karl Zeiss Meditec). Heidelberg Spectralis Spectral- Domain (SD) OCT was used for the microstructural examination of dental hard tissues. Visante (Carl Zeiss Meditec) OCT was used for the evaluation of the presence and structure of biofilm in vivo. Four Adults with intact teeth were included as control.
Results: The presence of surface biofilm was detected in every case as being between 25μm and 55μm thickness by TD-OCT. Different structural properties were detected as irregular, thin-continous and thick biofilm layers. The near-infrared wavelength of light used in SD- OCT verified dental micro-fractures between 15 μm- 95μm in width. The presence and varying amount of biofilm were also detected with Visante (Carl Zeiss Meditec) OCT.
Conclusion: The OCT imaging technique provided excellent resolution (5μm). In the biofilm microorganisms were present in an extracellular matrix layer made of polysaccharides, proteins and nucleic acid, which was produced by microbes. In this layer bacteria can exist in a safe environment. The antibiotic resistance is thousand times higher than in planktonic form. The authors consider the technique suitable for the evaluation of microstructural properties of biofilm on oral soft and hard tissues. Using OCT it is possible to gain new information about oral pathological conditions and microstructural changes.
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