PURPOSE : To investigate the incidence and prevalence of C-shaped root canal using computed tomographic images of head and neck in Korean population. MATERIALS AND METHODS : Regardless of each examination purpose, randomly selected 268 examples which have serial axial computed tomographic images with 8 normal molars in maxilla and mandible were selected and investigated. Defined C-shaped root canal and we could get 82 proper image examples in view of this definition. These were detected and investigated of incidence and prevalence of C-shaped root canal. RESULTS : C-shaped root canals were found in 82 examples among 268 (30.6%) and 147 teeth. They were only found on molar area, and the highest incidence was 37.41% of left mandibular second molars, and the lowest was 2.04% of right maxillary second molars. On prevalence of tooth position, mandibular second molar was the highest, 65% of C-shaped root canal teeth and maxillary second molar was 6% the lowest. CONCLUSION : 31% of randomly selected CT images no considering check-up reason have C-shaped root canals. The C-shaped root canals of mandibular second molar are found most frequently and they are also detectable on maxilla. On Korean population, C-shaped root canals are one of conditions that have to concern with dental treatment for it appears at a high prevalence relatively.
Dental Pulp Cavity ; Head ; Incidence ; Mandible ; Maxilla ; Molar ; Neck ; Prevalence ; Tooth

Primitive neuroectodermal tumor (PNET), which belongs to the Ewing's sarcoma (ES) family of tumors, is mainly seen in children and young adults. PNETs are extremely rare in the maxilla. Here, we report a case of PNET of the left maxillary sinus in an elderly male. Magnetic resonance imaging (MRI) revealed a slightly enhanced solid mass occupying the left maxillary sinus and infiltrating into the retroantral space. A partial maxillectomy was performed. Despite postoperative chemotherapy, follow-up computed tomography (CT) and MRI revealed a nodal metastasis in the submandibular space. Neck dissection was performed. However, the patient died 10 months after the second surgery because of distant metastasis to the liver. MRI and CT were particularly useful in detecting the extent of the tumor, recurrence, and metastasis. Further, a literature review of the previously reported PNET cases of the maxilla was carried out. In this paper, we also discuss the current approach for the diagnosis and management of these tumors.
Aged* ; Child ; Diagnosis ; Drug Therapy ; Follow-Up Studies ; Humans ; Liver ; Magnetic Resonance Imaging ; Male ; Maxilla ; Maxillary Sinus* ; Neck Dissection ; Neoplasm Metastasis ; Neuroectodermal Tumors, Primitive* ; Recurrence ; Sarcoma, Ewing ; Young Adult

OBJECTIVE: Screening tests for dysphagia have been introduced to prevent complications arising from dysphagia in stroke patients. Among them, Gugging swallowing screen (GUSS) was proven as an effective screening tests for dysphagia of stroke patients in 24 hours after onset. We compared several screening tests and clinical scales including GUSS. METHOD: Subjects were 37 stroke patients 3 months after onset. GUSS, 3 oz water test, Burke dysphagia screening test (BDST) and Standardized swallowing assessment (SSA) were carried out at bedside. VFS was performed in 24 hours after other studies were done. Functional dysphagia scale (FDS) and Penetration-aspiration scale (P/A scale) were derived from VFS. Clinical scales such as American Speech-Language-Hearing Association National Outcome Measurement System (ASHA NOMS) swallowing scale and Clinical dysphagia scale (CDS) were measured to see the correlation between GUSS and another dysphagia scales. RESULTS: GUSS had a sensitivity of 90.9% and a specificity of 69.2%. 3 oz water test had a sensitivity of 81.8% and a specificity of 76.9%. Sensitivity and specificity of BDST were respectively 90.9%, 61.5%. Sensitivity of SSA was 90.9%, specificity 61.5%. Correlation between GUSS and FDS was significant (r =-0.527, p<0.01). Correlation between GUSS and P/A scale also showed significance (r=-0.747, p<0.01). ASHA NOMS swallowing scale and GUSS showed significant correlation (r=0.432, p<0.01). CDS and GUSS showed significant correlation as well (r=-0.815, p<0.01). CONCLUSION: The screening ability of GUSS was equal to other screening tests for dysphagia of stroke patients. Correlations among GUSS and other VFS and clinical scales showed availability of GUSS as a clinical scale for dysphagia.

PURPOSE: The purpose of this study was to develop a system for the measurement and simulation of the TMJ movement and to analyze the mandibular movement quantitatively. MATERIALS AND METHODS: We devised patient-specific splints and a registration body for the TMJ movement tracking. The mandibular movements of the 12 subjects with facial deformity and 3 controls were obtained by using an optical tracking system and the patient-specific splints. The mandibular part was manually segmented from the CT volume data of a patient. Three-dimensional surface models of the maxilla and the mandible were constructed using the segmented data. The continuous movement of the mandible with respect to the maxilla could be simulated by applying the recorded positions sequentially. Trajectories of the selected reference points were calculated during simulation and analyzed. RESULTS: The selected points were the most superior point of bilateral condyle, lower incisor point, and pogonion. There were significant differences (P<0.05) between control group and pre-surgical group in the maximum displacement of left superior condyle, lower incisor, and pogonion in vertical direction. Differences in the maximum lengths of the right and the left condyle were 0.59+/-0.30 mm in pre-surgical group and 2.69+/-2.63 mm in control group, which showed a significant difference (P<0.005). The maximum of differences between lengths of the right and the left calculated during one cycle also showed a significant difference between two groups (P<0.05). CONCLUSION: Significant differences in mandibular movements between the groups implies that facial deformity have an effect on the movement asymmetry of the mandible.
Congenital Abnormalities ; Displacement (Psychology) ; Humans ; Incisor ; Mandible ; Maxilla ; Splints ; Temporomandibular Joint ; Track and Field

Acquired facial lipoatrophy is a rare disease with an unclear etiology and pathological pathway. The distinct causative factors of this disease have been not elucidated, but it is suspected to be associated with immune systemrelated diseases, most notably AIDS. Although the management of facial lipoatrophy is very important for patients’ social life and mental health, no treatment framework has been developed due to the unknown nature of the disease manifestation. The present case report was designed to provide sequential imaging to visualize the disease progression. The clinical backgrounds of the patients are also introduced, helping characterize this disease entity more clearly for maxillofacial specialists.

PURPOSE: To compare cephalometric measurement between measuring methods in digital and conventional lateral cephalometric radiograph. MATERIALS AND METHODS: Twenty digital and conventional lateral cephalometric radiographs were selected. In digital group, cephalometric measurements were performed manually using hardcopies and automatically using VCeph(TM) 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. RESULTS: 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 experience 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. CONCLUSION: With direct digital radiograph, automatic method using manually idenitified landmarks can be preferable in cephalometric analysis.
Cephalometry ; Radiographic Image Enhancement

PURPOSE: This study was performed to analyze human maxillary and mandibular trabecular bone using the data acquired from micro-computed tomography (micro-CT), and to characterize the site-specific microstructures of trabeculae. MATERIALS AND METHODS: Sixty-nine cylindrical bone specimens were prepared from the mandible and maxilla. They were divided into 5 groups by region: the anterior maxilla, posterior maxilla, anterior mandible, posterior mandible, and mandibular condyle. After the specimens were scanned using a micro-CT system, three-dimensional microstructural parameters such as the percent bone volume, bone specific surface, trabecular thickness, trabecular separation, trabecular number, structure model index, and degrees of anisotropy were analyzed. RESULTS: Among the regions other than the condylar area, the anterior mandibular region showed the highest trabecular thickness and the lowest value for the bone specific surface. On the other hand, the posterior maxilla region showed the lowest trabecular thickness and the highest value for the bone specific surface. The degree of anisotropy was lowest at the anterior mandible. The condyle showed thinner trabeculae with a more anisotropic arrangement than the other mandibular regions. CONCLUSION: There were microstructural differences between the regions of the maxilla and mandible. These results suggested that different mechanisms of external force might exist at each site.
Anisotropy ; Hand ; Humans* ; Imaging, Three-Dimensional ; Jaw* ; Mandible ; Mandibular Condyle ; Maxilla

PURPOSE: The objective of this study was to investigate the relationships between primary implant stability as measured by impact response frequency and the structural parameters of trabecular bone using cone-beam computed tomography(CBCT), excluding the effect of cortical bone thickness. METHODS: We measured the impact response of a dental implant placed into swine bone specimens composed of only trabecular bone without the cortical bone layer using an inductive sensor. The peak frequency of the impact response spectrum was determined as an implant stability criterion (SPF). The 3D microstructural parameters were calculated from CT images of the bone specimens obtained using both micro-CT and CBCT. RESULTS: SPF had significant positive correlations with trabecular bone structural parameters (BV/TV, BV, BS, BSD, Tb.Th, Tb.N, FD, and BS/BV) (P<0.01) while SPF demonstrated significant negative correlations with other microstructural parameters (Tb.Sp, Tb.Pf, and SMI) using micro-CT and CBCT (P<0.01). CONCLUSIONS: There was an increase in implant stability prediction by combining BV/TV and SMI in the stepwise forward regression analysis. Bone with high volume density and low surface density shows high implant stability. Well-connected thick bone with small marrow spaces also shows high implant stability. The combination of bone density and architectural parameters measured using CBCT can predict the implant stability more accurately than the density alone in clinical diagnoses.
Bone and Bones ; Bone Density ; Bone Marrow ; Cone-Beam Computed Tomography* ; Dental Implants* ; Diagnosis ; Swine ; X-Ray Microtomography

PURPOSE: The research was performed to predict the three dimensional relationship between the impacted mesiodens and the maxillary central incisors and the proximity with the anatomic structures by comparing their panoramic images with the CT images. MATERIALS AND METHODS: Among the patients visiting Seoul National University Dental Hospital from April 2003 to July 2007, those with mesiodens were selected (154 mesiodens of 120 patients). The numbers, shapes, orientation and positional relationship of mesiodens with maxillary central incisors were investigated in the panoramic images. The proximity with the anatomical structures and complications were investigated in the CT images as well. RESULTS: The sex ratio (M : F) was 2.28 : 1 and the mean number of mesiodens per one patient was 1.28. Conical shape was 84.4% and inverted orientation was 51.9%. There were more cases of anatomical structures encroachment, especially on the nasal floor and nasopalatine duct, when the mesiodens was not superimposed with the central incisor. There were, however, many cases of the nasopalatine duct encroachment when the mesiodens was superimpoised with the apical 1/3 of central incisor (52.6%). Delayed eruption (55.6%), crown rotation (66.7%) and crown resorption (100%) were observed when the mesiodens was superimposed with the crown of the central incisor. CONCLUSION: It is possible to predict three dimensional relationship between the impacted mesiodens and the maxillary central incisors in the panoramic images, but more details should be confirmed by the CT images when necessary.
Crowns ; Diagnostic Imaging ; Floors and Floorcoverings ; Humans ; Incisor ; Orientation ; Sex Ratio ; Tooth, Impacted

PURPOSE: The aim of this study was to evaluate the effect of liquid crystal display (LCD) monitor type and observer experience on the diagnostic performance in soft-copy interpretations of maxillary sinus inflammatory lesions on panoramic radiographs. MATERIALS AND METHODS: Ninety maxillary sinuses on panoramic images were grouped into negative and positive groups according to the presence of inflammatory lesions, using CT for confirmation. Monochrome and color LCDs were used. Six observers participated and ROC analysis was performed to evaluate the diagnostic performance. The reading time, fatigue score, and inter-/intra-observer agreements were assessed. RESULTS: The interpretation of maxillary sinus inflammatory lesions was affected by the LCD monitor type used and by the experience of the observer. The reading time was not significantly different, however the fatigue score was significantly different between two LCD monitors. Inter-observer agreement was relatively good in experienced observers, while the intra-observer agreement for all observers was good with monochrome LCD but not with color LCD. CONCLUSION: The less experienced observers showed lowered diagnostic ability with a general color LCD.
Fatigue ; Liquid Crystals ; Maxillary Sinus ; Organothiophosphorus Compounds ; ROC Curve ; Task Performance and Analysis