An update on optical coherence tomography in dentistry

Assessing diagnostic accuracy and monitoring of caries progression using optical coherence tomography (OCT): A systematic review

OBJECTIVES

This systematic review analyzed studies concerning the effectiveness of Optical Coherence Tomography (OCT) in detecting and monitoring dental caries in enamel and dentin.

DATA

Studies comparing the diagnostic accuracy of OCT in diagnosing caries clinically or using extracted teeth were included.

SOURCES

Databases, including PubMed/MEDLINE, Web of Science, EMBASE, and Scopus were searched for clinical trials and studies conducted using human teeth between 2010 and 2024. The process of study selection and data extraction followed the PRISMA guidelines. The methodological quality of the included studies was evaluated using the Critical Appraisal Skills Programme (CASP) diagnostic study checklist.

STUDY SELECTION

Seven studies met the inclusion criteria out of 1,266 articles identified. OCT modalities used in these studies include Cross-polarization OCT (CP-OCT), Swept-source OCT (SS-OCT), and polarization-sensitive (PS-OCT), with wavelengths ranging between 1310 and 1330 nm; axial resolutions were between 7.5-22 μm. SS-OCT had a high sensitivity of 74.1 % and specificity of 95.7 % when applied to caries detection. CP-OCT was able to identify dentin-penetrating lesions with greater accuracy than conventional radiography. There were strong correlations in the OCT measurements with the established diagnostic gold standards: polarized light microscopy (PLM), r = 0.63, P < 0.01; transverse microradiography (TMR), r = 0.75, P < 0.001.

CONCLUSION

OCT has demonstrated better performance regarding early caries detection and its activity compared with traditional diagnostic methods. However, standardization of the imaging protocol and further larger clinical trials are required.

CLINICAL SIGNIFICANCE

OCT offers significant clinical advantages in the diagnosis of dental caries. This technology enables early detection of carious lesions, facilitating timely intervention and potentially preserving tooth integrity. Investigating the clinical effectiveness of OCT is crucial to validate its utility in dental practice and to establish standardized protocols for its implementation in caries diagnosis.

Optical coherence tomography systems for evaluation of marginal and internal fit of ceramic reconstructions

Purpose

To evaluate the marginal and internal fit of lithium disilicate and zirconia crowns using two optical coherence tomography (OCT) systems in order to estimate inter-system variations.

Materials and methods

Ten lithium disilicate and 10 cubic stabilized zirconia crowns were placed on prepared artificial teeth without cement. Marginal discrepancy and internal cement gap of the crowns were assessed on images obtained using a swept source OCT (SS-OCT) and a spectral domain OCT (SD-OCT). Medians and interquartile ranges were calculated for both materials and OCT systems. Thereafter, Wilcoxon signed rank test was carried out.

Results

No significant difference was found between the two OCT systems for absolute marginal discrepancy of either lithium disilicate (SS-OCT: 182 µm, SD-OCT: 214 µm; p = .922) or zirconia crowns (SS-OCT: 116 µm, SD-OCT: 121 µm; p = .232). Regarding internal cement gap, no significant difference was found between the two OCT systems for lithium disilicate crowns (SS-OCT: 128 µm, SD-OCT: 128 µm; p = .064). However, for zirconia crowns the SD-OCT showed significantly higher (p = .027) internal cement gap (92 µm) than the SS-OCT (68 µm). Moreover, it was not possible to assess the internal fit of zirconia crowns in 47% and 34% of the sites using SD-OCT and SS-OCT, respectively.

Conclusions

No significant difference was noted in the ability of SS-OCT and SD-OCT to assess the marginal and internal fit of lithium disilicate crowns, nor the marginal fit of zirconia crowns. On the contrary, drawbacks regarding the assessment of internal fit of zirconia crowns using both OCT systems were observed.

The Use of Optical Coherence Tomography in Dental Diagnostics: A State-of-the-Art Review

Optical coherence tomography provides sections of tissues in a noncontact and noninvasive manner. The device measures the time delay and intensity of the light scattered or reflected from biological tissues, which results in tomographic imaging of their internal structure. This is achieved by scanning tissues at a resolution ranging from 1 to 15 μm. OCT enables real-time in situ imaging of tissues without the need for biopsy, histological procedures, or the use of X-rays, so it can be used in many fields of medicine. Its properties are not only particularly used in ophthalmology, in the diagnosis of all layers of the retina, but also increasingly in cardiology, gastroenterology, pulmonology, oncology, and dermatology. The basic properties of OCT, that is, noninvasiveness and low wattage of the used light, have also been appreciated in analytical technology by conservators, who use it to identify the quality and age of paintings, ceramics, or glass. Recently, the OCT technique of visualization is being tested in different fields of dentistry, which is depicted in the article.