Fusion patterns of the spheno-occipital synchondrosis in the age range of 9-22: A computed tomography analysis.

OBJECTIVES: To assess the fusion patterns of the spheno-occipital synchondrosis (SOS) in the age range of 9-22 using CT and CBCT images of an Iranian population. SETTING/SAMPLE POPULATION: Spiral CT and CBCT scans of 763 subjects (459 males and 304 females) aged 9-22 were evaluated. The scans had to cover the cranial base area, and those with diseases affecting the bone density, cranial base masses and history of trauma were excluded. MATERIALS AND METHODS: Two oral and maxillofacial radiologists scored the images with regard to the status of SOS fusion based on a 5-stage system. Mann-Whitney, Kruskal-Wallis and Fisher's exact tests were used for data analysis. Age and SOS fusion stages were evaluated through Spearman correlation and linear regression methods (α = 0.01). RESULTS: The earliest age for onset of SOS fusion was 9 in both sexes. Open SOS could be observed until the age of 15 and 14 in males and females, respectively. The earliest age of complete fusion was 12 in males and 13 in females. Furthermore, there was a significant, positive correlation between age and the different stages of SOS fusion (P < .001). CONCLUSION: A significant correlation exists between age and the fusion stages of SOS, rendering it an appropriate means of age estimation during growth periods. Fusion of SOS begins approximately 2 years earlier in females; however, it ends at the age of 17 in both sexes. The fusion scar can be detected up to the age of 12 and 13 in males and females, respectively.

Detection of peri-implant bone defects using cone-beam computed tomography and digital periapical radiography with parallel and oblique projection.

PURPOSE: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel (PPA) and oblique projected periapical (OPA) radiography for the detection of different types of peri-implant bone defects. MATERIALS AND METHODS: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects (10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. RESULTS: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects (P<0.05). CONCLUSION: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.