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

Ralph-Alexandru Erdelyi,Adrian Bradu,Adrian Podoleanu,George Mihai Dobre,Cosmin Sinescu,Virgil-Florin Duma

doi:10.3390/s21134554

Abstract

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 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm 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.

Highlights

In a recent study we explored the boundaries between Optical Coherence Tomography (OCT) and the common radiography when applied to maxillo-facial medical imaging [28]
While this is correct for a range of investigations, as we studied for example in [40], based on the quantitative assessments performed in [28] we demonstrated that radiography can spot relevant details such as small cavities, but cannot correctly measure them like OCT can
We developed an optimization procedure applicable to the common X-ray radiography for dental medicine using OCT, which presents a much higher resolution

Summary

Introduction

The discovery of X-rays in 1895 by Wilhelm Conrad Roentgen is considered to mark the beginning of medical imaging [1]. The techniques have improved continuously in the last two decades. One may consider in this respect, for example, the quality differences between the first radiographs and today’s 3D CBCTs [2]. Numerous other imaging techniques have been developed for dental medicine, but radiography has remained its most common investigation tool. Improving X-rays techniques is potentially of high impact due to their wide usage. The question is: how much room is there left for such improvements? The question is: how much room is there left for such improvements? how could they be achieved?

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Conclusion