Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

The most common imaging technique for dental diagnoses and treatment monitoring is

X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional

(3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential,

such as Optical Coherence Tomography (OCT).We have recently reported on the boundaries of these

two types of techniques, regarding. the dental fields where each one is more appropriate or where

they should be both used. The aim of the present study is to explore the unique capabilities of the

OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose,

or contrast). Two types of commercially available and widely used X-ray units are considered. To

adjust their parameters, a protocol is developed to employ OCT images of dental conditions that

are documented on high (i.e., less than 10 �m) resolution OCT images (both B-scans/cross sections

and 3D reconstructions) but are hardly identified on the 200 to 75 �m resolution panoramic or CBCT

radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for

the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order

to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The

optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied

in vivo for each type of dental investigation. Optimized radiographic results are compared with

un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous

comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible

using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of

dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental

diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative

images.