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[en] To investigate the hypothesis that the morphology of the articular eminence of the temporomandibular joint is a predisposing factor for disc displacement. MR images of 126 temporomandibular joints in 94 patients were analyzed to assess for morphology of the articular eminence and disc displacement. The displaced disc was further categorized as disc displacement with reduction (DDWR) and disc displacement without reduction (DDWOR). The morphology of the articular eminence was classified into four types; box, sigmoid, flattened, and deformed. The relationship between the four types of shape of the articular eminence and the two types of disc position was assessed. In the DDWR and DDWOR groups, the morphology of articular eminence were a box type in 40.5%, a sigmoid type in 30.2%, a flattened type in 24.6%, and a deformed type in 4.7%. The box type of the articular eminence were 34.3% in the DDWR group and 42.9% in the DDWOR group. The sigmoid type of the articular eminence were 34.3% in the DDWR group and 28.6% in the DDWOR group. The flattened type of the articular eminence were 28.6% in the DDWR group and 23.1% in the DDWOR group. The deformed type of the articular eminence were 2.9% in the DDWR group and 5.5% in the DDWOR group. Disc displacement in more likely to be found in the temporomandibular joints with a box-shaped articular eminence. It can be considered that shape of the articular eminence is related to the development of disc displacement
[en] To evaluate the condylar movement at maximal mouth opening on MRI in patients with internal derangement. MR images and transcranial views for 102 TMJs in 51 patients were taken in closed and maximal opening positions, and the amount of condylar movement was analyzed annotatively and qualitatively. For MR images, the mean condylar movements were 9.4 mm horizontally, 4.6 mm vertically and 10.9 mm totally, while those for transcranial views were 12.5 mm, 4.6 mm, and 13.7 mm respectively. The condyle moved forward beyond the summit of the articular eminence in 41 TMJs (40.2%) for MR images than in transcranial views
[en] Cleidocranial dysplasia is a rare, autosomal dominant congenital disorder. A 12-year-old female visited with chief complaint of unerupted permanent teeth. Also her father showed severe class III malocclusion. The extraoral radiography and computed tomography showed delayed closure of the cranial sutures and underdevelopment of maxilla, maxillary sinuses, and frontal sinus. Both clavicles were underdeveloped and thoracic rib cage was bell-shaped. Both zygomatic process appeared as hypoplastic feature. There were many unerupted permanent and supernumerary teeth in the maxilla and mandible. We examined location and number of the unerupted teeth using 3D CT. Finally we could conclude this case was cleidocranial dysplasia based on the clinico-radiologic findings.
[en] To aid in determining the volume of graft bone required before a maxillary sinus lift procedure and compare the alveolar bone height measurements taken by panoramic radiographs to those by CT images. Data obtained by both panoramic radiographs and CT examination of 25 patients were used in this study. Maxillary sinus volumes from the antral floor to heights of 5 mm, 10 mm, 15 mm, and 20 mm , were calculated. Alveolar bone height was measured on the panoramic images at each maxillary tooth site and corrected by magnification rate (PBH). Available bone height (ABH) and full bone height (FBH) was measured on reconstructed CT images. PBH was compared with ABH and FBH at the maxillary incisors, canines, premolars, and molars. Volumes of the inferior portion of the sinuses were 0.55 ± 0.41 cm3 for 5 mm lifts, 2.11 ± 0.68 cm3 for 10 mm, 4.26 ± 1.32 cm3 for 15 mm, 6.95 ± 2.01 cm3 for 20 mm. For the alveolar bone measurement, measurements by panoramic images were longer than available bone heights determined by CT images at the incisor and canine areas, and shorter than full bone heights on CT images at incisor, premolar, and molar areas (p<0.001). In bone grafting of the maxillary sinus floor, 0,96 cm3 or more is required for a 5 mm - lift, 2.79 cm3 or more for a 10 mm - lift, 5.58 cm3 or more for a 15 mm - lift, and 8.96 cm3 or more for a 20 mm - lift. Maxillary implant length determined using panoramic radiograph alone could result in underestimation or overestimation, according to the site involved.
[en] To evaluate the relationship between morphometric analysis of microstructure from digital radiographic image and trabecular bone strength. One hundred eleven bone specimens with 5 mm thickness were obtained from the mandibles of 5 pigs. Digital images of specimens were taken using a direct digital intraoral radiographic system. After selection of ROI(100 x 100 pixel) within the trabecular bone, mean gray level and standard deviation were obtained. Fractal dimension and the variants of morphometric analysis (trabecular area, periphery, length of skeletonized trabeculae, number of terminal point, number of branch point) were obtained from ROI. Punch sheer strength analysis was performed using Instron (model 4465, Instron Corp., USA). The loading force (loading speed 1mm/min) was applied to ROI of bone specimen by a 2 mm diameter punch. Stress-deformation curve was obtained from the punch sheer strength analysis and maximum stress, yield stress, Young's modulus were measured. Maximum stress had a negative linear correlation with mean gray level and fractal dimension significantly (p<0.05). Yield stress had a negative linear correlation with mean gray level, periphery, fractal dimension and the length of skeletonized trabeculae significantly (p<0.05). Young's modulus had a negative linear correlation with mean gray level and fractal dimension significantly (p<0.05). The strength of cancellous bone exhibited a significantly linear relationship between mean gray level, fractal dimension and morphometric analysis. The methods described above can be easily used to evaluate bone quality clinically.
[en] A case of sialadenitis is presented in a patient with painful swelling of the right mouth floor. The condition was caused by trauma on the right mouth floor during dental treatment, which had happened 15 days before admission. On aspiration, mucous secretion was found and ultrasonography showed obstruction of duct. Histopathological studies and surgical investigation established a definite diagnosis of obstructive sialadenitis caused by ductal laceration. As surgical treatment sialodochoplasty was selected. The case and relevant considerations are discussed.
[en] To compare cephalometric measurement between measuring methods in digital and conventional lateral cephalometric radiograph. Twenty digital and conventional lateral cephalometric radiographs were selected. In digital group, cephalometric measurements were performed manually using hard copies and automatically using V-CeptTM program on the monitor. In conventional group, the same measurements were performed manually on conventional films, and for automatic measurement conventional films were digitized by scanner. All measurements were performed twice by 4 observers, and 24 cephalometric variables were calculated and the time spent for each measurement was recorded. The differences in measurements data and the time spent for each measurement were compared within each group. Intra-observer and inter-observer comparisons were performed. In both groups, no statistically significant difference between manual and automatic measurements was observed and most of the variables didn't show statistically significant differences between methods. The observer with less experiences tended to show statistically significant differences of measurements between methods, and differences from other observers. The differences of measurements between methods in digital group were lesser than those of conventional group with statistical significance in 8 variables out of 24. With automatic method and in digital group, the spent time was shorter. With direct digital radiograph, automatic method using manually identified landmarks can be preferable in cephalometric analysis.
[en] To find statistically based information about the natural variation in the length of the styloid process and to show the influence of the gender and age on the length of the styloid process. 1,300 panoramic radiographs were retrieved from inactive files at the Dental Hospital of Kyung Hee University. Measurements of the length of the styloid process were made directly on the radiographs from the interior margin of the tympanic plate to the tip of the styloid process. The mean length of 948 styloid processes was 25.2 mm ± 6.6. The median was 24.5 mm, and the inter-quartile range was 7 mm. The mean length was 25.7 mm for male and 24.6 mm for female. All percentile was greater for male than for female. The median is 25 mm for male and 24 mm for female. This study suggests that the difference of the styloid process length between genders was statistically significant and the length of styloid process was significant increased with age until 30 years.
[en] To evaluate the magnification error percentage in repeatedly taken panoramic radiographs of same patient and machine. 92 panoramic radiographs from 46 patients were traced and 30 horizontal and vertical measurements were made with digital sliding caliper. The results were compared with paired t-test. There are no statistically significant difference between the two measurements. The overall difference as percentage error was 6.19 ± 5.60%. The largest error as 14.61 ± 12.44% was found at condylar height 1, and smallest as 1.56 ± 1.41% at mandibular height. Overall vertical error excluding condylar height 1 was 3.76 ± 3.97%, and the horizontal error 6.88 ± 5.92%. Repeatedly taken panoramic radiographs of the same patient and machine was reliable since there was no significant percentage error difference but the percentage error ranged from 1.86 ± 1.61% to 14.61 ± 12.44% indicating the error depends on the measuring site.
[en] To compare the effects of the conservative treatment and operative treatment by observation of osseous changes of the TMJ and mandibular asymmetry in condylar fracture patients. 33 condylar fracture patients (17 with conservative and 16 with operative treatment) were included in this study. After a minimum of 6 months after the surgical procedure, patients were given a follow up examination of the osseous changes using a transcranial view. Differences in the osseous changes of both groups were compared and the asymmetry indices were calculated on a postero-anterior skull view. The TMJ of the operative treatment group showed more significant osseous changes than the conservative treatment group. The affected TMJ showed more significant osseous changes than the unaffected TMJ in the both groups. The unaffected TMJ of the conservative group and the affected TMJ of the operative group showed significant osseous changes. The mandibular asymmetry indices in the conservative and operative group were 5.12 and 7.30 respectively at the time of treatment, and 2.39 and 3.41 respectively at the follow-up. But the mandibular asymmetry between the both groups showed no statistical differences. The TMJ of the operative group showed more significant osseous changes than the conservative group, but the mandibular asymmetry between the both groups showed no statistical differences.