• Clinics in Shoulder and Elbow
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• v.19 no.3
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• pp.143-148
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• 2016

Background: The purpose of our study was to evaluate the accuracy of reduction based on postoperative computed tomography (CT) images after arthroscopic stabilization using tightrope system for unstable distal clavicle fracture. Methods: Twelve patients with distal clavicle fracture combined with coracoclavicular (CC) ligament injury (type II, V) who received arthroscopically assisted fixation using a flip button device were evaluated for accuracy of reduction using 3-dimensional postoperative CT scan by measuring the degree of distal clavicular angulation and clavicular shortening. Results: Immediate postoperative plain radiograph confirmed restoration of the CC distance (CCD) in 10 patients. At final follow-up, the CCD remained reduced anatomically on plain radiographs in these patients. All patients showed excessive posterior angulation and shortening compared to the opposite side. The average Constant score recovered to 94.8 at final follow-up. Conclusions: Indirect reduction and arthroscopic subacromial approach with flip button fixation of unstable distal clavicle fractures demonstrated favorable clinical results despite unavoidable posterior angulation of distal clavicle and shortening the total length of clavicle.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.161-167
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• 2006

Objectives: Pericoronitis was the most common indication for mandibular third molar surgery and there are no universally acceptable predictive criteria for pericoronitis occurrence. This study was designed to analyze the correlation of the pericoronitis and the eruption state of the mandibular third molar using panoramic radiographs statistically. Materials and Methods: 218 patients whose chief complaint was the extraction of the mandibular third molar were examined. The presence and absence of pericoronitis, age, sex, position of extraction site, angulation, impaction degree, position to the anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar were assessed. Then the correlation of pericoronitis and the eruption state of the mandibular third molar were analyzed by Student's t-test and chi-square test. Results: There was no correlation between Pericoronitis and age, sex, position of the mandibular third molar. The angulation(P=0.005), impaction degree(P=0.043), relation with anterior border of mandibular ramus(P=0.003), distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar(P<0.05) were correlated with pericoronitis. Conclusions: The occurrence of the pericoronitis can be predicted by the eruption state of the mandibular third molar such as angulation, impaction degree, relation with anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of third molar.

• Imaging Science in Dentistry
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• v.33 no.1
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• pp.15-20
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• 2003

Purpose : To investigate the reproducibility of the conventional and digital radiographs to determine the depth of approximal root cavities. Materials and Methods : A total of 80 artificial root cavities were prepared in the approximal surfaces of premolars, maxillary and mandibular molars. Standardized radiographs were taken at the baseline (0° horizontal and 0° vertical) and at a horizontal angulation of 10° in both mesial and distal directions. Radiographic cavity depths were measured by both conventional and digital radiographs. Results: At 0° horizontal angulation, no statistically significant differences could be determined between the results of conventionally and digitally determined radiographic depths with respect to the actual cavity depths in all premolar, maxillary, and mandibular molar groups. All conventional and digital radiographic depths at both 10° mesial and distal angulations showed statistically significant increases in depth compared to the actual cavity depths (p < 0.05), with the exception of digital radiographic depth at 10° mesial angulation for premolars. There were no statistically significant differences between conventional and digital radiographic depths for all groups. Conclusion: The present study suggests that both conventional and digital radiographs provide reproducible assessment of the depth of the approximal root cavity. But horizontal X-ray beam movements are likely to result in increase in radiographic cavity depth.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.155-163
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• 1988

The purpose of this study was to evaluate and compare frictional forces generated between orthodontic brackets and arch wires. Independent variables were chosen for study: arch wire size and shape, arch wire material, bracket width, and second-order angulation between bracket and arch wire. Kinetic frictional forces of stainless steel (0.014', 0.016', 0.018', 0.016' ${\times}$ 0.022', 0.018' ${\times}$ 0.022'), $\beta-titanium$ (0.016' ${\times}}$ 0.022') arch wires were measured on wide and junior edgewise twin brackets (0.018' ${\times}$ 0.022' slot). Instron was used to pull arch wires while $0^{\circ},\;3^{\circ},\;6^{\circ},\;or\;9^{\circ}$ angulation between and wire and bracket was given. The results were as follows: 1. The frictional force of $\beta-titanium$ wire was larger than that of stainless steel wire. 2. The frictional force was generally increased as the size of wire is increased. 3. The frictional force of rectangular wire was larger than that of round wire. 4. As second order angulation was increased, the frictional force was also increased. 5. The frictional force was larger on a wide bracket than on a junior bracket.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.230-238
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• 2018

Purpose: Metacarpal fractures are common injuries of the hand. They are treated using closed reduction (CR) or open reduction (OR) techniques. The management strategy depends on fracture site characteristic and fixation methods. In this study, we evaluated pre- and postoperative fracture angulation, when metacarpal fractures bad been treated using two different techniques: CR with parallel transverse pinning and OR with plate fixation. Methods: Forty-six patients undergoing anatomic reduction to treat extra-articular metacarpal fractures were recruited. They were included in one of two therapeutic groups: Group 1, CR with parallel transverse pinning (n=21); Group 2, OR with plate fixation (n=25). Fracture angulation values have been measured on pre- and postoperative radiologic images. Values were compared between pre- and postoperative states, and between corresponding measurements of each group. Results: All extra-articular metacarpal fractures were successfully treated without wound related complications or the limit of joint motion. Both groups demonstrated adequate reduction at immediate postoperative period (postoperative angulation of group 1, $20^{\circ}{\pm}7^{\circ}$; group 2, $19^{\circ}{\pm}5^{\circ}$). During the observation at follow-up period, Group 1 exhibited slight recurrence (follow-up angulation of group 1, $24^{\circ}{\pm}10^{\circ}$). Nonetheless, Group 2 showed adequate reduction state in both immediate postoperative and long-term follow-up periods (follow-up angulation of group 2, $18^{\circ}{\pm}6^{\circ}$). Conclusion: Extra-articular metacarpal fractures were successfully restored without functional complications. CR with parallel transverse pinning method exhibited recurrence after pin removal, which necessitates cautious postoperative exercise and monitoring.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.1
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• pp.67-75
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• 1992

Transcranial radiograph is widely used in the diagnosis of craniomandibular disorder because it can be used by the dentist with relative ease in spite of image distortion. But correct information can be obtained only when one know the image change by projection angulation. The author compared the condyle position in the 3 groups of transcranial radiographs (horizontal angulation - 0°, 5°, individualized) with that in the individualized corrected lateral tomogram by objective and subjective evaluation methods. The results were as follows: 1. Among 3 transcranial groups, the condyle position in individualized group showed the highest concordance rate with that in the tomogram group in objective and subjective evaluation methods. 2. Correlation coefficient between individualized transcranial group and tomogram group in objective evaluation method was highest (P≤0.01). 3. Image clarity in individualized transcranial group was worse than that of the other two transcranial groups.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.1
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• pp.127-132
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• 1995

A number of panoramic radiographic images of the condylar head taken at various horizontal angulations were compared. A small artificial osteophyte was attached to the eight different portions of the condylar head and a small hole was created in four different portions of the condylar head. Three oral and maxillofacial radiologists evaluated the panoramic condylar images. The results were as follows : 1. Osteophytes in the superomedial, anterocentral and anterolateral portions could be detected easily, but those in the lateral, superolateral and medial portions were very hard to identify. 2. The greater the condylar horizontal angle, the easier it was to detect an osteophyte. But there was no statistically significant difference except between 0 and 40 degrees of horizontal angulation. 3. Holes in the anterocentral and superocentral portions could be detected easily, but those in the lateral and medial portions were very hard to identify. There were no differences between the various condylar horizontal angles.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.4
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• pp.529-540
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• 1995

The paper deals with a procedure for constructing a composite surface interpolating a polygonal curve mesh defined from 3D scattered points. The procedure consists of a poly-angulation, construction of a curve net, and interpolation of the curve net. The poly-angulation contains a stage that changes a triangular edge net obtained from a triangulation into a poly-angular edge net. A curve net is constructed by replacing edges on the edge net with cubic Bezier curves. Finally, inside of an n-sided polygon is interpolated by n subdivided triangular subpatches. The method interpolates given point data with relatively few triangular subpatches. For an n-sided polygon, our method constructs an interpolant with n subdivided triangular subpatches while the existing triangular surface modeling needs 3(n-2) subpatches. The obtained surface is composed of quartic triangular patches which are $G^1$-continuous to adjacent patches.

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.245-256
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• 1989

Translational movement along an arch wire requires sufficient force to overcome frictional forces between bracket and arch wire. The orthodontist must appreciate the importance of friction in this process, and study out the influencing factors on the level of friction. The purpose of this study was to evaluate the effect of artificial saliva on frictional resistances generated between the bracket and arch wire. Independent variables of this study were arch wire material, angulation and environment. Static frictional forces of cobalt-chromium, heat-treated cobalt-chromium, beta-titanium, stainless steel wires were measured under non-angulated dry, angulated dry, non-angulated saliva, angulated saliva conditions. The results were as follows: 1. Stainless steel wires showed lower friction values in non-angulated dry condition, and heat-treated cobalt-chromium wires showed higher friction values in angulated dry condition. Higher friction values were showed in order of cobalt-chromium. stainless steel, heat-treated cobalt-chromium and beta-titanium wires in non-angulated saliva condition. and were showed in order of stainless steel, cobalt-chromium, heat-treated cobalt-chromium, beta-titanium wires in angulated saliva condition. 2. Angulation increased friction for stainless steel wires under dry condition. 3. Artificial saliva decreased friction for cobalt-chromium wires and increased friction for stainless steel wires under non-angulated condition. 4. Artificial saliva decreased friction for all wires except beta-titanium wires under angulated condition. 5. Regardless of angulation or environment. heat-treated cobalt-chromium and beta-titanium wires showed higher friction values, and stainless steel wires showed lower friction values.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.209-212
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• 2009

Objective : Avascular necrosis (AVN) of the vertebral body is known as a relatively uncommon phenomenon in a vertebral compression fracture (VCF). The outstanding radiologic findings of AVN are intravertebral vacuum phenomenon with or without fluid collection. Several reports revealed that PVP or balloon kyphoplasty might be the effective treatment modalities for AVN. We also experienced excellent results when using PVP for the treatment of AVN of the vertebral body, and intend to describe the treatment's efficacy in this report. Methods : Thirty-two patients diagnosed with AVN of the vertebral body were treated with PVP. We measured the pre- and post-operative anterior body height and kyphotic angulation. The visual analogue scale (VAS) was used to determine the relief of back pain. Results : The anterior body height (pre-operative : 1.49 cm, post-operative : 2.22 cm) and kyphotic angulation (pre-operative : 14.47 degrees, post-operative : 6.57 degrees) were significantly restored (p<0.001). VAS was improved from 8.9 to 3.7. Pseudoarthrosis was corrected in all cases, which was confirmed by dynamic radiographs. Fluid collection was found in sixteen cases and was aspirated with serous nature. No organism and tumor cell were noted. Conclusion : PVP proved to be an effective procedure for the treatment of AVN of the vertebral body, which corrected dynamic instability and significantly restored the anterior body height and kyphotic angulation.