A conventional optical coherence tomography (OCT) system was set up in-house to image early dental caries, identify gap formation in the bonding interface for restoration and secondary caries. Two-dimensional images of tooth samples was obtained and dental defect were identified. A novel electro-optic tuning system is proposed in order to improve scanning speed and to perform noiseless imaging. Preliminary studies were conducted with two crystals namely, LiNbO<inf>3</inf> (Lithium Niobate) and KTP (Potassium Titanyl Phosphate) using a SLED source for OCT system and the simulated and experimental results were found to be qualitatively similar. The tuning range for LiNbO<inf>3</inf> and KTP was found to be in the order of few micrometers whereas KTN (Potassium Tantalate Niobate) using the quadratic electro-optic effect is expected to show scanning range of tens of micrometers. KTN based hybrid scanning for dental caries imaging is also planned. © 2014 IEEE.

Nilesh Jayanthilal Vasa

Department of Engineering Design

Vani Damodaran

Lithium niobate

Niobium

oxide

phosphate

POTASSIUM TITANYLPHOSPHATE

titanium

chemistry

Computer simulation

Dental caries

Electronics

Human

optical coherence tomography

Pathology

procedures

signal processing

three dimensional imaging

time

Tooth

Humans

Imaging, Three-Dimensional

Oxides

Phosphates

Signal Processing, Computer-Assisted

Time Factors

TOMOGRAPHY, OPTICAL COHERENCE

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Development of an electro-optically tuned optical coherence tomography system for imaging dental lesions.

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014

A high-speed 840 nm based polarization-sensitive time domain optical coherence tomography (PSOCT) technique is proposed and demonstrated based on the quadratic electro-optic property of potassium tantalate niobate (KTN) crystals. A longitudinal (axial) scanning depth of ≈10 μm is obtained for an applied AC voltage of 600 V, at 1000 Hz and temperature maintained around 40°C. The OCT system with the KTN-based electro-optic delay line combined with a linear actuation is extended to image an early dental demineralization. For enhanced contrast by the elimination of the strong surface reflection from the sample and high-speed imaging, the quadratic electro-optically tunable PSOCT technique is proposed and demonstrated. Further, a lateral scanning range of 490 μm is also demonstrated by controlling the KTN temperature at 35°C for an applied voltage of 600 V on the tooth sample. This KTN-based quadratic electro-optic delay line combined with lateral scan approach provides an automated high-speed two-dimensional scanning of samples of interest. © 2018 Optical Society of America.

Applied Optics

KTN-based high-speed axial and lateral scanning technique for an optical coherence tomography system and application to dental imaging

The Optical coherence tomography (OCT) based technique is proposed and demonstrated for determining the progress of dental caries. A conventional OCT system was setup in-house and was used to image natural caries, artificial caries and secondary caries with a resolution of 6.26 pm and 12.30 pm corresponding to 840 nm and 1310 nm, respectively. Dental caries were simulated artificially by mimicking the acidity of the oral cavity and imaged at different time intervals for upto 60 hours of demineralisation. The caries progression was estimated from the OCT images by measuring the thickness of the scattering and was found to be 45 to 50 micrometer deep in the 840 nm imaging and 40 to 48 micrometer deep for 1310 nm imaging for 60 hours of demineralisation. The same study was performed in an accelerated demineralisation environment in order to study the progression of caries and was found to be 200 to 210 micrometer deep for 68 hours of demineralisation. © 2015 IEEE.

2015 Workshop on Recent Advances in Photonics, WRAP 2015

Imaging artificially induced dental caries using optical coherence tomography near 800 and 1300 nm region

In this paper, a study of in-house built optical coherence tomography (OCT) system with a wavelength of 840 nm for imaging of dental caries, progress in demineralisation and cavity restoration is presented. The caries when imaged with the 840 nm OCT system showed minute demineralisation in the order of 5 μm. The OCT system was also proposed to study the growth of lesion and this was demonstrated by artificially inducing caries with a demineralisation solution of pH 4.8. The progress of carious lesion to a depth of about 50-60 μm after 60 hours of demineralisation was clearly observed with the 840 nm OCT system. The tooth samples were subjected to accelerated demineralisation condition at pH of approximately 2.3 to study the adverse effects and the onset of cavity formation was clearly observed. The restoration of cavity was also studied by employing different restorative materials (filled and unfilled). In the case of restoration without filler material (unfilled), the restoration boundaries were clearly observed. Overall, results were comparable with that of the widely used 1310 nm OCT system. In the case of restoration with filler material, the 1310 nm OCT imaging displayed better imaging capacity due to lower scattering than 840 nm imaging. © 2016 Elsevier Ltd. All rights reserved.

Optics and Lasers in Engineering

Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

Dental Materials Journal

3D evaluation of composite resin restoration at practical training using swept-source optical coherence tomography (SS-OCT)

Optical Review

Tomographic imaging of incipient dental-caries using optical coherence tomography and comparison with various modalities

Progress In Electromagnetics Research C

THREE-DIMENSIONAL IMAGE OF THE HUMAN TOOTH BASED ON OPTICAL COHERENCE TOMOGRAPHY

Journal of Applied Physics

Space-charge-controlled electro-optic effect: Optical beam deflection by electro-optic effect and space-charge-controlled electrical conduction

Biological and Medical Physics, Biomedical Engineering

Optical Coherence Tomography

Development of an electro-optically tuned optical coherence tomography system for imaging dental lesions

Journal	Data powered by Typeset2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers Inc.
Open Access	No