Resolution characteristics of optical coherence tomography for dental use

The purpose of this study was to clarify the resolution characteristics of optical coherence tomography (OCT) for dental use.

Two types of swept-source optical coherence tomography machines were employed in this study. To clarify their resolution characteristics, we newly developed a glass chart device with a ladder pattern of wavelengths, which ranged from 4 × 2 μm to 1024 × 2 μm, as well as a star-target pattern, a grid pattern and a spatial frequency response pattern. The resolving powers and characteristics of the OCTs were subjectively evaluated.

The Santec OCT-2000^™ (Santec Co., Komaki, Japan) had a resolving power of 64 μm in both the horizontal X and vertical Y directions, while the OCT from Yoshida had a resolving power of 64 μm in the horizontal X direction and 128 µm in the vertical Y direction. The resolving power of the depth Z direction could not be obtained from this study. With the Yoshida OCT, the star-target pattern seemed to be non-symmetrical, owing to an edge enhancement effect, which was revealed when the ladder patterns were placed in a horizontal direction.

This study successfully clarified the resolution characteristics of two types of OCTs. The obtained data may be useful for diagnostic purposes, and the glass chart device used in this study may be useful for OCT quality assurance programmes.