Optical Coherence Tomography-Based Detection of Dental Decay

Objectives: Optical Coherence Tomography (OCT) is a non-invasive, high resolution imaging modality analogous to ultrasound, but using light. Aim of this study was to evaluate the diagnostic effectiveness of OCT for the detection of primary and secondary coronal and radicular decay. Methods: 160 extracted human teeth were divided into groups of 40 teeth. Group 1: 20 teeth with early occlusal caries plus 20 healthy controls. Group 2: 20 teeth with occlusal sealants and underlying decay plus 20 controls. Group 3: 20 teeth with class 1 restorations and secondary decay plus 20 controls. Group 4: 20 teeth with class 2 restorations and secondary decay plus 20 controls. Group 5: 20 teeth with secondary radicular caries plus 20 controls. Standardized clinical photographs, radiographs and OCT images were acquired for each sample. 2 blinded, pre-standardized scorers diagnosed each lesion independently using separate clinical exam, radiographs, and OCT. Evaluation criteria included presence/absence of decay per site, as well as lesion size. Results: Non-invasive OCT imaging was rapid (less than 5s per scan) and easy. Caries was easily recognized in the OCT image by its differing optical intensity from the adjacent tooth substance and resin. For Group 1, agreement between OCT diagnosis and clinical diagnosis was 19/20 for healthy teeth (k=0.95) and 19/20 for teeth with early occlusal decay (k=0.95). For Group 2, k=1.00 and 0.95 for specimens with healthy vs. carious tooth substance under sealants. For Group 3, k=0.95 and 0.85 respectively; for Group 4, k=0.85 and 0.80 and for Group 5 k=1.00 and 0.90. OCT consistently performed better than radiographs, especially in detecting early primary or secondary decay (p<0.05), except when decay was restricted to areas >2mm below the tooth surface. Conclusion: OCT is effective for caries detection. Funding: NIH EB-00293, CA-91717, RR-01192, Lantis Laser Inc