Accuracy of extraoral tuned aperture computed tomography (TACT) for proximal caries detection.

OBJECTIVES: The objectives of this study were to compare the difference in the accuracy of proximal caries detection by extraoral tuned aperture computed tomography (TACT), intraoral TACT, and film radiographs. STUDY DESIGN: Eighty proximal surfaces of 40 extracted human maxillary teeth were used. A digital sensor was the image receptor for TACT. Film radiographs were acquired using Insight film. Nine basis images were acquired to reconstruct TACT slices. Seven observers scored the presence or absence of proximal caries using the 3 imaging modalities. The true presence of caries and its depth were determined using the sectional images obtained by micro CT. Among the image modalities and observers, possible differences in the area under the receiver operating characteristic curve were assessed by analysis of variance (ANOVA). RESULTS: ANOVA indicated no statistically significant differences between observers (P = .845), modalities (P = .657), and observer-modality combinations (P = .593). CONCLUSION: Within the limited range of this study, extraoral TACT was not statistically different from intraoral TACT or film radiographs for proximal caries detection. This suggests that extraoral TACT may have some clinical utility for caries diagnosis and that further study may be warranted.

Diagnostic ability of extraoral tuned aperture computed tomography (TACT) for impacted third molars.

OBJECTIVES: The purpose of this study was to evaluate the capabilities of a newly developed extraoral TACT system for diagnosing impacted third molars. STUDY DESIGN: Three dry human mandibles with impacted third molars were used. Nine base images were obtained by the extraoral and intraoral TACT methods. Four board-certified oral and maxillofacial radiologists evaluated TACT slice images as to whether the TACT images could clearly show the periodontal space of the impacted third molar, and the location of the tooth relative to the second molar, or to the mandibular canal. The criteria were excellent, good, fair, poor, and unreadable. RESULTS: Only the visibility of the periodontal space in extraoral TACT was significantly inferior to that of intraoral TACT. Almost all of the series of TACT images, however, were graded as excellent or good. CONCLUSION: The results indicate that extraoral TACT is a useful modality for the clinical assessment of impacted third molars.