Diagnostic accuracy of panoramic radiography, stereo-scanography and cone beam CT for assessment of mandibular third molars before surgery.

OBJECTIVE: To compare the diagnostic accuracy of panoramic imaging, stereo-scanography and cone beam computed tomography (CBCT) for assessment of mandibular third molars. MATERIAL AND METHODS: One hundred and twelve patients (147 third molars) underwent radiographic examination by panoramic imaging, stereo-scanography and CBCT. Tooth angulation, root morphology, number of roots and relation to the mandibular canal were assessed. The same variables were assessed intra- and post-operatively and served as reference for the radiographic assessments. The diagnostic accuracy for each variable was compared between the three modalities and accuracy was further expressed as sensitivity and specificity and tested between the modalities for identifying the relation to the mandibular canal. RESULTS: There were no significant differences between the modalities regarding tooth angulation, root morphology and number of roots. However, CBCT was more accurate than stereo-scanography for determining root bending in the bucco-lingual plane (p = 0.02). Moreover, sensitivity for direct contact to the mandibular canal (panoramic imaging: 0.29, stereo-scanography: 0.57, CBCT: 0.67) was higher for CBCT than for panoramic images (p = 0.05) and specificity for no direct contact to the mandibular canal (panoramic imaging: 0.78, stereo-scanography: 0.53, CBCT: 0.68) was higher for panoramic images and CBCT than for scanograms (p < 0.001). CONCLUSION: Panoramic imaging, stereo-scanography and CBCT seem equally valuable for examination of tooth angulation, number and morphology of roots of mandibular third molars. However, CBCT was more accurate for assessment of root bending in the bucco-lingual plane and more accurate than panoramic images to identify direct contact to the mandibular canal.

Head motion and perception of discomfort by young children during simulated CBCT examinations.

OBJECTIVES: To assess the frequency and characteristics (number, complexity, and distance) of head movements, and the perception of discomfort during simulated CBCT examinations in children, considering units with different patient positioning method and head immobilization device combinations. METHODS: Forty children (20 boys/20 girls, age range 10-14 years) were video-recorded during simulated CBCT examinations. Children were randomly allocated to a sequence of five CBCT units: Newtom-5G, Orthophos-SL, Cranex-3Dx (patient standing/sitting), and X1. The child scored his/her discomfort perception (visual scale) and the preferred/ill-favored unit. Three observers scored the videos (20% in duplicate): child movement (yes/no), number (<3/≥3/continuous), complexity (uniplanar/multiplanar) and distance (<3 mm/≥3 mm). κ statistics provided intra-/interobserver reproducibility. Severe/extreme motion was defined based on movement characteristics. Chi-square tests assessed the frequency differences of severe/extreme motion among the units, age and operator. Logistic regression analyses with severe/extreme motion as outcome were performed. RESULTS: The range of intra- and inter-observer reproducibility for movement observation was 0.78-0.89 and 0.61-0.64, respectively. Between 60% (Newtom-5G) and 100% (X1) of children moved during the examination. Severe/extreme motion was significantly related to unit and age. There was significantly less severe/extreme motion, when the child was in the supine position with a foam headrest as head support. The younger the child, the higher the risk for severe/extreme motion. The majority of the children preferred the unit with the supine position and a foam headrest. CONCLUSIONS: The prevalence of severe and extreme motion was associated with the unit's patient positioning method and head immobilization devices combined, and child age.