Diagnostic accuracy of cone-beam computed tomography with modified grayscale range for detection of buccal cortical plate defects adjacent to dental implants.

Background: This study assessed the diagnostic accuracy of cone-beam computed tomography (CBCT) with a modified grayscale range for the detection of buccal cortical plate defects adjacent to dental implants. Materials and Methods: In this in vitro experimental study, titanium implants were inserted in 168 fresh bovine bone blocks with 1-1.5 mm of buccal cortical plate thickness. The blocks were randomly divided into four groups (n = 42). No defect was created in the control blocks. In the three experimental groups, cortical plate defects were randomly created in the cervical, middle, or apical third by a round bur with a 2-mm diameter (n = 42). All blocks underwent CBCT with and without change in the grayscale range. Two observers evaluated all images regarding the presence/absence of defects. Kappa test is used for the agreement of the observers. The diagnostic accuracy of the two modalities was compared by calculating the area under the receiver operating characteristic curve (AUC) (P ≤ 0.05). The sensitivity and specificity values were also compared. Results: The AUC was not significantly different between the two modalities with and without altered grayscale range (0.754 vs. 0.762, respectively, P = 0.716). The diagnostic sensitivity of CBCT with and without change in the grayscale range was 51% and 52%, respectively, with a specificity of 100% for both. The diagnostic accuracy of CBCT with and without altered grayscale range had no significant difference for apical and middle third defects (P > 0.05) and was significantly higher than that for the cervical third defects (P < 0.05). Conclusion: Changing the grayscale range does not improve the diagnostic accuracy of CBCT for the detection of buccal cortical plate defects adjacent to dental implants.

Efficacy of cone-beam computed tomography with modified gray-scale range versus digital periapical radiography for the assessment of bone-implant interface gaps.

OBJECTIVES: To compare the efficacy of digital periapical (PA) radiography with cone-beam computed tomography (CBCT) by altering the gray-scale range for the detection of bone-implant interface gaps. METHODS: Titanium implants were placed in 52 blocks of bovine rib such that 42 had no gaps and served as the control group. The implants were subsequently placed in the same blocks with 0.25 mm increase in the osteotomy size to serve as the test group. The remaining 10 blocks were used for random arrangement of the test and control blocks within a fabricated wax arch. CBCT with change in the gray-scale range and digital PA were obtained and evaluated by two observers regarding the presence/absence of gaps. The two imaging modalities were compared by the receiver operating characteristic (ROC) curve, Kappa and McNemar tests (α = 0.05). RESULTS: PA and CBCT showed moderate agreement for gap detection (k = 0.60). There were no significant differences in the area under the ROC curve (AUC) between CBCT and PA (P = 0.45). The frequency of correct diagnoses on PA radiographs was significantly higher in the test group (P = 0.016), while not significant on the CBCT images (P = 0.344). PA showed higher sensitivity (100%) compared to CBCT (83.33%). However, the specificity of CBCT (92.86%) was greater than that of PA (83.33%). CONCLUSIONS: Certain gray-scale ranges in CBCT enhance the assessment of bone-implant interface which brings the accuracy of CBCT closer to digital PA radiography as the modality of choice.

Prevalence and patterns of palatine and adenoid tonsilloliths in cone-beam computed tomography images of an Iranian population.

BACKGROUND: Tonsilloliths are calcified concretions that develop in tonsillar crypts. They are usually small and asymptomatic, so they are found accidentally during routine dental radiogrphy procedure. Large tonsilloliths can occur with clinical signs and symptoms. The purpose of this study was to evaluate the prevalence and patterns of palatine and adenoid tonsilloliths in cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: In this cross-sectional study, 0.5-mm axial and coronal slices of 134 CBCT images were evaluated to determine the presence of palatine and adenoid calcifications. Their patterns such as being unilateral or bilateral as well as single or multiple and their largest linear sizes were reported. RESULTS: Fifty-four (40.3%) patients with palatine tonsilloliths and 17 (12.7%) with adenoid calcifications were found. Thirty (55.6%) palatine tonsilloliths were unilateral, 19 (35.2%) were detected in the left tonsils. Approximately, 54 cases of 78 palatine calcifications were multiple. Seventeen patients had adenoid calcifications that 41.1% of them were unilateral. Fourteen adenoid calcifications were single. The mean ages of patients with palatine tonsilloliths and adenoid calcifications were 45.59 years and 46.53 years, respectively. The range of linear measurements of palatine tonsil calcifications was 0.9-4.2 mm (2.47-mm mean size) while adenoid calcifications ranged from 0.5 to 2.2 mm (0.95-mm mean size). The level of statistical significant difference was <0.05. CONCLUSION: Gender did not affect total prevalence, the pattern of tonsilar calcifications and their linear sizes. The prevalence of tonsilloliths increased with aging, but this variable did not have an effect on their linear size.

Comparison between cone beam computed tomography and panoramic radiography in the assessment of the relationship between the mandibular canal and impacted class C mandibular third molars.

BACKGROUND: Preoperative radiographic evaluation of impacted third molars is essential to determine the proximity to the mandibular canal to minimize the risk of nerve injury. Our study aim was to evaluate the relationship between the mandibular canal and impacted mandibular third molars using cone beam computed tomography (CBCT) and to compare findings therein with panoramic radiographic signs. METHODS: CBCT images were taken from 29 patients having 43 Class C impacted mandibular third molars whose panoramic radiographs showed a close relationship between the mandibular canal and mandibular third molars. We evaluated their tomographs to determine the course of the canal, its proximity to the root, any narrowing of the canal, the presence of root grooving or hooks and the proximity of the root to the cortex. A Chi-square test was used for data analysis. RESULTS: The lingual course of the canal was the most frequently detected course in all panoramic findings. Contact of the tooth with the canal was observed in all cases in which panoramic signs of deviation of the canal and darkening of the roots were found. The frequency of observing the narrowing of the canal in CBCT as compared to seeing the presence or the absence of canal narrowing in panoramic radiographs was significantly different (P=0.01). CONCLUSION: CBCT provides more precise diagnostic information to determine the relationship of impacted third molars to the canal. Deviation of the canal and darkening of the roots in panoramic view can be highly valuable to predict the risk of nerve injury.