Influence of CBCT parameters on image quality and the diagnosis of vertical root fractures in teeth with metallic posts: an ex vivo study.

Objectives: The aim of this study was to evaluate the influence of peak kilovoltage (kVp) and a metal artifact reduction (MAR) tool on image quality and the diagnosis of vertical root fracture (VRF) in cone-beam computed tomography (CBCT). Materials and Methods: Twenty single-rooted human teeth filled with an intracanal metal post were divided into 2 groups: control (n = 10) and VRF (n = 10). Each tooth was placed into the socket of a dry mandible, and CBCT scans were acquired using a Picasso Trio varying the kVp (70, 80, 90, or 99), and the use of MAR (with or without). The examinations were assessed by 5 examiners for the diagnosis of VRF using a 5-point scale. A subjective evaluation of the expression of artifacts was done by comparing random axial images of the studied protocols. The results of the diagnoses were analyzed using 2-way analysis of variance and the Tukey post hoc test, the subjective evaluations were compared using the Friedman test, and intra-examiner reproducibility was evaluated using the weighted kappa test (α = 5%). Results: The kVp and MAR did not influence the diagnosis of VRF (p > 0.05). According to the subjective classification, the 99 kVp protocol with MAR demonstrated the least expression of artifacts, while the 70 kVp protocol without MAR led to the most artifacts. Conclusions: Protocols with higher kVp combined with MAR improved the image quality of CBCT examinations. However, those factors did not lead to an improvement in the diagnosis of VRF.

Brightness and contrast adjustments influence the radiographic detection of soft tissue calcification.

OBJECTIVE: To assess the influence of subjective enhancement of brightness and contrast of digital panoramic radiographs on the detection of soft tissue calcifications. MATERIALS AND METHODS: In this observational study, 500 digital panoramic radiographs were evaluated by two examiners in consensus, who scored the images for the presence of calcifications for each right and left side of the image. After 30 days, all images were revaluated under subjective manipulation of digital brightness and contrast. Calcifications were classified based on the diagnostic hypothesis: sialolith, tonsillolith, calcified atheroma, phlebolith, rhinolith, maxillary sinus antrolith, synovial chondromatosis, lymph node calcification, stylohyoid ligament, triticeous cartilage, or/and upper horn of thyroid cartilage calcification. For intra-examiner agreement, 20% of the sample was reevaluated. The Kappa test and McNemar test were used (α = 0.05). RESULTS: In original images, calcifications were observed in 44.2% of the patients, and in enhanced images, this number was 70.8%. Many calcifications were detected only in enhanced images, mainly in the diagnostic hypotheses of calcified atheroma and stylohyoid ligament. Intra-examiner agreement was excellent for the detection of soft tissue calcifications (0.82) and for the classification (0.81). CONCLUSION: Subjective enhancement of brightness and contrast alters the detection of soft tissue calcifications in digital panoramic radiograph.

Influence of acquisition parameters on the evaluation of mandibular third molars through cone beam computed tomography.

OBJECTIVES: The aim of the study was to assess the influence of cone beam computed tomography (CBCT) acquisition parameters on the evaluation of mandibular third molars and their relationship to the mandibular canal. STUDY DESIGN: Eight dry human mandibles with 13 mandibular third molars were scanned with one CBCT unit. Voxel size (0.2 and 0.3 mm), field of view (FOV) size (12 × 8.5 cm and 5 × 5 cm), and number of basis images (450 and 720) were the variables studied. Two examiners evaluated the images, and the resulting data were compared through McNemar, McNemar-Bowker, and Student t tests. Additionally, dosimetry was determined for all protocols tested, and radiation doses were compared through analysis of variance. RESULTS: The variables did not influence evaluation of mandibular third molars, except for voxel size, when assessing contact between the tooth and the mandibular canal (P = .021). Although FOV and number of basis images affected radiation dose, voxel size did not. CONCLUSIONS: FOV size and number of basis images did not influence the evaluation of mandibular third molars and their relationship to the mandibular canal in the CBCT unit used. Conversely, smaller voxel size affected the assessment of contact between the tooth and the mandibular canal. In units in which voxel size does not influence radiation dose, the most appropriate CBCT protocol is the one using a smaller voxel size and delivering the lowest radiation dose to the patient.