ABSTRACT
OBJECTIVES: This study aimed to assess the effect of voxel size on detection of fenestration, dehiscence, and furcation defects using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: This in vitro, experimental study evaluated 4 sheep skulls with both the maxilla and mandible accompanied by the surrounding soft tissue. Fenestration (n = 30), dehiscence (n = 65), and furcation defects (n = 46; 18 grade I, 25 grade II, and 3 grade III) were randomly created by round and needle burs in both jaws, and 40 areas served as control sites. CBCT scans were obtained with 0.300 and 0.150 mm3 voxel sizes and 8 × 11cm2 field of view (FOV), and were randomly observed by four observers (two oral and maxillofacial radiologists and two periodontists). The kappa values, sensitivity and specificity were calculated for each voxel size and compared using paired t test. RESULTS: By an increase in image resolution, diagnostic sensitivity increased while specificity decreased. The kappa values for fenestration (0.602-0.623), and grade III furcation defects (0.903-1.00) were optimal (> 0.6), and almost similar for both voxel sizes. The kappa values for dehiscence, and grades I and II furcation defects were unfavorable (< 0.6) and almost similar for both voxel sizes, except for grade I furcation defects, which had a significant difference in kappa values between the two voxel sizes (0.014 and 0.34). CONCLUSION: Smaller voxel size had higher sensitivity and lower specificity for detection of all defects except for grade I furcation defects, for which the smaller voxel size had higher sensitivity and higher specificity.
Subject(s)
Furcation Defects , Animals , Cone-Beam Computed Tomography , Mandible , Maxilla , SheepABSTRACT
BACKGROUND: Oral squamous cell carcinoma (SCC) is the most common cancer of oral region. The characteristic feature of SCC is invasion of dysplastic epithelium into the connective tissue. Oral SCC is more common in old patients. It is believed that etiology and pathogenesis of SCC in young patients differ from old patients and it is related to different molecular mechanism. In this study, histopathologic differentiation and proliferation activity (by Ki67) in oral SCC lesions of young patient (<40 years) and old patients (>50 years) have been compared. MATERIALS AND METHODS: In a cohort study, Formalin Fixed and paraffin-embedded tissue sections of 20 oral SCC of young patients and 20 oral SCC of old patients were stained by H and E and immunohistochemically by biotin-streptavidin method. They were observed by two pathologists. Histological grade and Ki67 labeling index (LI) were determined. Data were analyzed by t-test and Mann-Whitney. RESULTS: In cases of oral SCC in young patients, 80% were grade I and 20% were grade II and Ki67 LI was 21/5% in this age group. In cases of oral SCC in old patients, 75% were grade I and 25% were grade II and Ki67 LI was 21/6% in this age group. CONCLUSION: Histological and immunohistochemical evidence of this study show that oral SCC of young patients and oral SCC lesions of old patients didn't show any differences in histopathological differention and proliferative activity.
