Tuned aperture computed tomography (TACT[reg ]) for cross-sectional implant site assessment in the posterior mandible

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.

Comparative diagnostic performance of TACT®slices and its multiple source images: anin vitrostudy

OBJECTIVE

To compare the diagnostic performances provided by tuned aperture computed tomography (TACT) slices and the multiple images that they originate from in the detection of primary caries on the proximal surfaces of posterior teeth.

STUDY DESIGN

Eight direct digital radiography images of each of 40 posterior teeth were acquired with a digital sensor. These source images were used to generate TACT slices of the teeth. Eight trained observers were calibrated in the use of both TACT slices and the eight source images of each tooth. They were asked to assess the presence/absence of proximal caries in the teeth using a 5-point rating scale. Observers' assessments were compared with the ground truth provided by histological examination of tooth sections. Areas under the receiver operating characteristic (ROC) curves (Az) were calculated for each combination of observer and image modality. Analysis of variance (ANOVA) was used to test the ROC values for potential statistical differences.

RESULTS

Mean ROC Az values were 0.760 for TACT slices and 0.771 for its multiple source images for the detection of primary proximal caries. ANOVA showed no statistically significant differences either between modalities (P = 0.656) or between observers (P = 0.851).

CONCLUSION

TACT slices and its multiple source images provide comparable diagnostic performance for proximal caries detection.