• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.5
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• pp.356-360
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• 2017

The tympanic plate is a small part of the temporal bone that separates the mandibular condyle from the external auditory canal. Fracture of this small plate is rare and usually associated with other bony fractures, mainly temporal and mandibular bone. There is a limited amount of literature on this subject, which increases the chance of cases being overlooked by physicians and radiologists. This is further supported by purely isolated cases of tympanic plate fracture without evidence of other bony fractures. Cone-beam computed tomography is an investigative three-dimensional imaging modality that can be used to detect fine structures and fractures in maxillofacial trauma. This article presents four cases of isolated tympanic plate fracture diagnosed by cone-beam computed tomography with no evidence of fracture involving other bones and review of the literature.

• Imaging Science in Dentistry
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• v.36 no.3
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• pp.123-129
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• 2006

The use of computed tomography for dental procedures has increased recently. Cone beam computed tomography (CBCT) systems have been designed for imaging hard tissues of the dentomaxillofacial region. CBCT is capable of providing high resolution in images of high diagnostic quality. This technology allows for 3-dimensional representation of the dentomaxillofacial skeleton with minimal distortion, but at lower equipment cost, simpler image acquisition and lower patient dose. Because this technology produces images with isotropic sub-millimeter spatial resolution, it is ideally suited for dedicated dentomaxillofacial imaging. In this paper, we provide a brief overview of cone beam scanning technology and compare it with the fan beam scanning used in conventional CT and the basic principles of currently available CBCT systems.

• The Journal of the Korean dental association
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• v.53 no.12
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• pp.967-974
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• 2015

Purpose: This study was performed to investigate the characteristics of mandibular incisive canal (MIC) in Korean population. Materials and methods: A total of 97 subjects (60 males and 37 females) who underwent cone-beam computed tomography were included in the study. The anatomic features of MIC was assessed according to gender. Length, diameter and distance to inferior, lingual and buccal border were measured at the origin and the terminal. Also the distribution of MIC at each tooth position was evaluated. Results: Of 97 patients included, 75(77.3%) presented bilateral MIC and 13(13.4%) presented unilateral MIC. Of 194 hamimandibles, MIC was detected in 102(85%) sites in male and 61(82.4%) sites in female. Gender and side showed no statistically significant differences in detectability. The length, diameter and distance to adjacent structures were bigger in male than in female except the distance to lingual border. MIC travelled anteriorly in a slightly downward and lingual direction and usually terminated between the first premolar and the canine. On cross-sectional view, MIC showed individually scattered distribution both buccolingually and superoinferiorly. Conclusion: MIC is well detected with cone-beam computed tomography. Considered that the length and the location of MIC has large variations between individuals, its localization using cone-beam CT is highly recommended before performing surgical procedures such as implant placement and bone harvesting.

• Imaging Science in Dentistry
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• v.50 no.4
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• pp.365-371
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• 2020

While silent sinus syndrome (SSS) is familiar to otolaryngologists and ophthalmologists, it is a rare clinical entity in dentistry and is likely to be underdiagnosed due to dentists' lack of awareness of this condition. SSS presents a diagnostic challenge to dentists, as patients typically have no history of trauma or sinusitis. The characteristic feature of SSS is a gradual retreat of the maxillary sinus walls, resulting in enophthalmos and hypoglobus. Multidetector (multislice) computed tomography is the imaging modality of choice for SSS and other paranasal sinus diseases. Cone-beam computed tomography promises to be an alternative low-dose imaging modality. This report describes 3 cases of SSS in adults, who had no identified clinical symptoms except diminutive and opacified maxillary sinuses, as well as the inward bowing of the sinus walls as noted on cone-beam computed tomographic imaging.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.309-312
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• 2013

A retromolar canal is an anatomical variation in the mandible. As it includes the neurovascular bundle, local anesthetic insufficiency can occur, and an injury of the retromolar canal during dental surgery in the mandible may result in excessive bleeding, paresthesia, and traumatic neuroma. Using imaging analysis software, we evaluated the cone-beam computed tomography (CT) images of two Korean patients who presented with retromolar canals. Retromolar canals were detectable on the sagittal and cross-sectional images of cone-beam CT, but not on the panoramic radiographs of the patients. Therefore, the clinician should pay particular attention to the identification of retromolar canals by preoperative radiographic examination, and additional cone beam CT scanning would be recommended.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.103-109
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• 2006

Purpose : To evaluate position of the mandibular condyle within articular fossa in an asymptomatic population radiographically by a cone beam computed tomography. Materials and Methods : Cone beam computed tomography of 60 temporomandibular joints was performed on 15 males and 15 females with no history of any temporomandibular disorders, or any other orthodontic or prosthodontic treatments. Position of mandibular condyle within articular fossa at centric occlusion was evaluated. A statistical evaluation was done using a SPSS. Results : In the sagittal views, mandibular condyle within articular fossa was posteriorly located at medial and central sections. In the coronal views, mandibular condyle within articular fossa was laterally located at central section. Mandibular condyles in the right and left sides were showed asymmetric positional relationship at medial, central, and lateral sections. Conclusion : Mandibular condyle within articular fossa in an asymptomatic population was observed nonconcentric position in the sagittal and coronal views.

• Imaging Science in Dentistry
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• v.39 no.1
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• pp.27-33
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• 2009

Purpose: The purpose of this study was to evaluate the clinical usefulness of the recently developed multi-detector computed tomography and cone beam computed tomography in pre-operative implant evaluation, by comparing them with the single detector computed tomography, already confirmed for accuracy in this area. Materials and Methods: Five partially edentulous dry human mandibles, with $1{\times}1mm$ gutta percha cones, placed in 5mm intervals posterior to the mental foramen on each side of the buccal part of the mandible, were used in this study. They were scanned as follows: 1) Single detector computed tomography: slice thickness 1mm, 200mA, 120kV 2) Multi-detector computed tomography: slice thickness 0.75mm, 250mA, 120kV 3) Cone beam computed tomography: 15mAs, 120kV Axial images acquired from three computed tomographies were transferred to personal computer, and then reformatted cross-sectional images were generated using V-Implant $2.0^{(R)}$ (CyberMed Inc., Seoul, Korea) software. Among the cross-sectional images of the gutta perch a cone, placed in the buccal body of the mandible, the most precise cross section was selected as the measuring point and the distance from the most superior border of the mandibular canal to the alveolar crest was measured and analyzed 10 times by a dentist. Results: There were no significant intraobserver differences in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). There were no significant differences among single detector computed tomography, multi-detector computed tomography and cone beam computed tomography in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). Conclusion: Multi-detector computed tomography and cone beam computed tomography are clinically useful in the evaluation of pre-operative site for mandibular dental implants, with consideration for radiation exposure dose and scanning time.

• The Journal of the Korean dental association
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• v.52 no.12
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• pp.753-761
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• 2014

Purpose: This study was performed to examine distribution of accessory mandibular canal and its characteristics in mandibular third molars. Materials and methods: A total of 251 subjects (166 males and 85 females) having mandibular third molars bilaterally were included in the study. Cone-beam computed tomographic images were reviewed for bifid or trifid accessory mandibular canal. The prevalence of accessory mandibular canal was evaluated according to gender, side and its branching type. Proximity and crosssectional position of accessory mandibular canal to mandibular third molar was analyzed. Results: Accessory mandibular canals were found in 66 (26.3%) of 251 patients and 86 (17.1%) of 502 hemi-mandibles. Gender and sides showed no statistically significant differences in prevalence. Retromolar canal (46.1%) was the most common branching type. Proximity of accessory canal to mandibular third molars showed mean distance of 2.8 mm from third molar and a statistically significant difference was found among types of accessory canal. Dental canal was the closest to tooth among branching types and closer to tooth than main canal. On cross-sectional view, accessory canal was generally located on buccal side of mandibular third molar. Conclusion: Accessory mandibular canal was common and well detected with cone-beam computed tomography. Their localization is significant in all anesthetic and surgical procedures involving mandibular third molars.

• Imaging Science in Dentistry
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• v.48 no.2
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• pp.79-86
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• 2018

Purpose: This study aimed to carry out a systematic review of studies in the literature comparing conventional imaging techniques with cone-beam computed tomography in terms of the role of these techniques for assessing any of the following periodontal conditions and parameters: infrabony defects, furcation involvement, height of the alveolar bone crest, and the periodontal ligament space. Materials and Methods: Interventional and observational studies comparing conventional imaging techniques with cone-beam computed tomography were considered eligible for inclusion. The MEDLINE and Embase databases were searched for articles published through 2017. The PRISMA statement was followed during data assessment and extraction. Results: The search strategy yielded 351 publications. An initial screening of the publications was performed using abstracts and key words, and after the application of exclusion criteria, 13 studies were finally identified as eligible for review. Conclusion: These studies revealed cone-beam computed tomography to be the best imaging technique to assess infrabony defects, furcation lesions, the height of the alveolar bone crest, and the periodontal ligament space.

• Imaging Science in Dentistry
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• v.37 no.2
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• pp.93-102
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• 2007

Purpose: Cone beam computed tomography (CBCT) provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology. The purpose of this study was to evaluate the absorbed and effective doses of Implagraphy and VCT (Vatech Co., Hwasung, Korea) and compare them with those of panoramic radiography. Materials and Methods: Thermoluminescent dosimeter (TLD) chips were placed at 27 sites throughout the layers of Female ART Head and Neck Phantom for dosimetry. Implagraphy, VCT units, and Planmeca Proline XC panoramic unit were used for radiation exposures. Radiation weighted doses and effective doses were measured and calculated using 1990 and 2005 ICRP tissue weighting factors. Results: Effective doses in Sv (ICRP 2005, ICRP 1990) were 90.19, 61.62 for Implagraphy at maxillay molar area, 123.20, 90.02 for Implagraphy at mandibular molar area, 183.55, 139.26 for VCT and 40.92, 27.16 for panoramic radiography. Conclusion: Effective doses for VCT and Implagraphy were only about 2.2 to 4.5 times greater than those for panoramic radiography. VCT and Implagraphy, CBCT machines recently developed in Korea, showed moderately low effective doses.