Relationship between pterygomaxillary fissure morphology and maxillary/mandibular position : A cone beam computed tomography assessment.

PURPOSE: The aim of this study was to investigate the possible correlation between maxillary and mandibular positioning via cephalometric analysis with pterygomaxillary fissure (PMF) morphology using cone beam computed tomography (CBCT). METHODS: In this study, CBCT images from 825 individuals (448 female, 377 male; age range was 18-91 years with this cohort) were analyzed; PMF length and width were measured. Three-dimensional cephalometric analysis was also performed using cephalometric analysis software. The landmarks and measurements in relation to maxillary and mandibular positions were identified and performed for the cephalometric analysis. Analysis of variance (ANOVA) was used for comparison of the parameters, while the Bonferroni test was used for multiple comparisons. Pearson's test was also used to assess the correlations between the parameters. RESULTS: The results showed that males had significantly larger PMF length (p < 0.001) and width (p < 0.001) compared to females. The mean PMF length was 17.7 mm (standard deviation [SD] 3.2 mm) for right and 17.7 mm (SD 3.3 mm) for left but were not significantly different (p > 0.05). In terms of the cephalometric measurements, a significant correlation was found between upper central incisor (U1toAperp2D) and posterior facial height (PostFaceHtSGo2D) and PMF length, while correlations were found between PMF width and several cephalometric parameters such as lower lip (LwLiptoEPln2D and LwLiptoHLine2D) and occlusal plane (OPtoFHAng2D) (p < 0.05). CONCLUSION: A significant relationship was observed between PMF morphology and the position of the maxilla or mandible. PMF lengths and widths were larger in males than females. Posteroanterior maxillary and mandibular lengths and posterior facial height are associated with PMF length and width.

Evaluation of articular eminence pneumatization using cone beam computed tomography.

AIM: Knowledge about the anatomy of the temporomandibular joint (TMJ) and its surrounding structures is mandatory for success in surgical interventions and for understanding the pathway of spread of infections in this region. This study aims to investigate the anatomy and morphology of pneumatized articular eminence (PAT) using cone beam computed tomography (CBCT) imaging in a group of patients. METHODS: A retrospective study on 825 patients (377 males, 448 females) aged between 18 and 91 years was performed using sagittal and coronal CBCT images. PAT was defined as non-expansile, nondestructive cyst-like radiolucency in the zygomatic process of the temporal bone, which appears similar to the mastoid air cells. It was classified in two groups as unilocular and multilocular. Statistical comparison of gender, age and localization was performed using chi-square test and correspondence analysis. P<0.05 was considered as significant. RESULTS: Twenty-eight pneumatized articular eminence were found in 21 patients, representing a prevalence of 2.54%. Patients with PAT had a mean age of 28.9 years with a range of 21-78 years. Ten cases (47.6%) occurred in females and 11 cases (52.4%) occurred in males. The results of statistical tests showed no significant differences among the groups with respect to gender, age, and localization (P>0.05). CONCLUSION: Pneumatization of the articular eminence is a challenging entity for TMJ surgery and spread of infections in this region. Practitioners who are dealing with TMJ surgery and pathology should have detailed information about this anatomical variation since it may cause serious complications.

Diagnostic accuracy of cone beam computed tomography and conventional multislice spiral tomography in sheep mandibular condyle fractures.

OBJECTIVES: the aim of this study was to compare diagnostic accuracy of cone beam CT (CBCT) and multislice CT in artificially created fractures of the sheep mandibular condyle. METHODS: 63 full-thickness sheep heads were used in this study. Two surgeons created the fractures, which were either displaced or non-displaced. CBCT images were acquired by the NewTom 3G CBCT scanner (NIM, Verona, Italy) and CT imaging was performed using the Toshiba Aquillon multislice CT scanner (Toshiba Medical Systems, Otawara, Japan). Two-dimensional (2D) cross-sectional images and three-dimensional (3D) reconstructions were evaluated by two observers who were asked to determine the presence or absence of fracture and displacement, the type of fracture, anatomical localization and type of displacement. The naked-eye inspection during surgery served as the gold standard. Inter- and intra-observer agreements were calculated with weighted kappa statistics. The receiver operating characteristics (ROC) curve analyses were used to compare statistically the area under the curve (AUC) of both imaging modalities. RESULTS: kappa coefficients of intra- and interobserver agreement scores varied between 0.56 - 0.98, which were classified as moderate and excellent, respectively. There was no statistically significant difference between the imaging modalities, which were both sensitive and specific for the diagnosis of sheep condylar fractures. CONCLUSIONS: this study confirms that CBCT is similar to CT in the diagnosis of different types of experimentally created sheep condylar fractures and can provide a cost- and dose-effective diagnostic option.

Accuracy of chemically created periapical lesion measurements using limited cone beam computed tomography.

OBJECTIVES: The aim was to assess the accuracy and reproducibility of measurements of chemically created periapical lesions using limited cone beam CT. METHODS: Periapical lesions were chemically created in 18 mandibular cadaver teeth. Mandibles were dissected buccolingually using a bone-cutting burr. Diameters and depths were measured directly in the cross-sectional slices using a precision digital caliper. The cross-sectional slices were then embedded in wax, and cone beam CT images were acquired using a NewTom 3G Plus scanner with both 6 inch and 9 inch fields of view (FOVs). Two oral radiologists measured the diameter and depth of periapical lesions on the cross-sectional images using the built-in measurement tools. Measurements were repeated after a 1 week interval. Inter- and intraobserver agreement was calculated by ANOVA. Regression analysis was used to test the correlation between the cone beam CT and digital caliper measurements. RESULTS: No significant differences were found in diameter or depth measurements between or within observers or between 6 inch and 9 inch FOV images. Regression analysis of diameter and depth measurements made by direct caliper versus 6 inch or 9 inch FOV images revealed a high regression coefficient (for diameter: 6 inch FOV, R(2) = 94.6%; 9 inch FOV, R(2) = 94.8%; P<0.001; for depth: 6 inch FOV, R(2) = 99.3%; 9 inch FOV, R(2) = 99.3%; P<0.001) showing a strong linear relationship. For the diameter, the mean deviation from direct caliper measurements was 0.0625 mm and 0.08958 mm, respectively; for the 6 inch FOV and 9 inch FOV images, and for depth, the mean deviation was, respectively, -0.1001 mm and 0.09875 mm. CONCLUSIONS: Cone beam CT yielded highly accurate and reproducible results in the quantitative assessment of periapical lesions.