Comparative assessment of CBCT-synthesized bitewing radiography for occlusal and interproximal caries depth detection: an in vitro study

Introduction
Dental caries, a common chronic disease, significantly impacts oral health and quality of life. Accurate diagnosis of caries depth is crucial for effective treatment and preventing severe tooth damage.

Objectives
The study aimed to evaluate the diagnostic accuracy of cone-beam computed tomography (CBCT)-synthesized bitewing (CSBW) radiography for detecting occlusal and interproximal caries depth.

Material and methods
A total of 160 posterior teeth were mounted in two dry human skulls in five stages, with imaging at each stage, resulting in 20 CSBW radiographs obtained from Carestream CS 9600 CBCT system, and 40 intraoral bitewing (IBW) radiographs from MINRAY® intraoral X-ray unit and DIGORA® Optime scanner and photostimulable phosphor plates. Two observers evaluated the radiographs twice with a one-week interval to measure the depth of occlusal and interproximal caries.

Results
For the detection of caries depth, CSBW radiography demonstrated the highest sensitivity (100%), speci­ficity (96.3%), accuracy (0.96), and area under the curve (AUC) (0.95) than the histopathological gold standard. Compared with IBW, CSBW exhibited the highest sensitivity (94.3%), specificity (100%), accuracy (0.98), and AUC (0.91). CSBW showed the highest agreement with the gold standard in mesial and distal surfaces (87.5%), and the lowest agreement in occlusal surface (75%). The agreement between CSBW and IBW was the highest for occlusal surfaces (98.9%), and the lowest for mesial surfaces (89.6%).

Conclusions
CSBW radiography presents high diagnostic accuracy for the detection of occlusal and interpro­ximal caries depth. It offers an efficient and patient-friendly alternative to IBW radiography, especially for those who have difficulty with intraoral imaging.