• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.420-430
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• 2008

Statement of problem & Purpose: Articulators are very important for education and overall clinical situation in the field of prosthodontics, however preexisting articulators are designed and built based on maxillofacial structures and mean values of mandibular movement of Western people. Purpose of this research is to find out a adequate basis for applicating these articulators, presently used for clinical education, for Korean. Material and methods: 59 Korean adults (41 males, 18 females), aged between 24 to 41, where selected for this study. Two pairs of both maxillary and mandibular models were made for each examinee. These models where attached to both KaVo PROTARevo 7 and Hanau Modular semiadjustable articulators by using facebow transfer, than sagittal condylar inclination, occlusal plane inclination and position of mandibular on the articulator where measured. Result and conclusion: 1. Mean sagittal condylar inclination for KaVo PROTAR semiadjustable articulator was $33.75^{\circ}$(standard deviation $12.46^{\circ}$) meanwhile Hanau Modular semiadjustable articulator showed $40.72^{\circ}$(standard deviation $12.09^{\circ}$) for mean sagittal condylar inclination. 2. Mean occlusal plane inclination for KaVo PROTAR semiadjustable articulator was $-2.76{\circ}$(standard deviation $3.63^{\circ}$) meanwhile Hanau Modular semiadjustable articulator showed $11.87^{\circ}$ (standard deviation $3.63^{\circ}$) for mean occlusal plane inclination. 3. On the average center of the mandibular dentition were in the range of 5 to 7 mm of the central position of the articulator. Both anterior and posterior dentition were positioned at the center of the articulator vernacularly for KaVo PROTAR semiadjustable articulators, meantime for Hanau Modular semiadjustable articulator, anterior dentition was positioned 5 mm downwards and 3mm upwards for posterior dentition from vertically central position of the articulator.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.246-251
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• 2014

In case of prosthesis fabrication by CAD/CAM, location, area and contour of occlusal contacts can be adjusted so more functional occlusion can be acquired. Also, errors in a manufacturing process is reduced compared to cast metal prostheses and porcelain fused metal prostheses fabricated by conventional methods such as casting and porcelain build up. Therefore, prostheses by CAD/CAM show superior occlusion accuracy. Recently, virtual articulator function has been introduced to CAD/CAM system, which reproduces mandibular movement against maxilla. Thus, it is possible to consider occlusal interference in anterior/lateral movement as well as closing movement. There have been many studies on the marginal and internal fit of prostheses using zirconia but the occlusal fit of zirconia crown fabricated by CAD/CAM has not been researched as much. In this case report, 7 zirconia crowns were designed and fabricated by CAD/CAM for total 5 patients. The models of zirconia crowns before and after occlusal adjustment during intraoral try-in were scanned for occlusal contacts, which were compared to evaluate accuracy of prostheses and understand patterns of occlusal adjustment. Most of the occlusal adjustments were done on functional cusps and slopes of zirconia crown, and the magnitude of occlusal adjustment ranged from $15{\mu}m$ to $60{\mu}m$. In the zirconia crown fabricated with CAD/CAM systems, the occlusal adjustment is a necessary procedure, so additional procedures will be needed for compensating reduced mechanical properties.

• The korean journal of orthodontics
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• v.43 no.3
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• pp.134-140
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• 2013

Objective: To evaluate lower incisor position and bony support between patients with Class II average- and high-angle malocclusions and compare with the patients presenting Class I malocclusions. Methods: CBCT records of 79 patients were divided into 2 groups according to sagittal jaw relationships: Class I and II. Each group was further divided into average- and high-angle subgroups. Six angular and 6 linear measurements were performed. Independent samples t-test, Kruskal-Wallis, and Dunn post-hoc tests were performed for statistical comparisons. Results: Labial alveolar bone thickness was significantly higher in Class I group compared to Class II group (p = 0.003). Lingual alveolar bone angle (p = 0.004), lower incisor protrusion (p = 0.007) and proclination (p = 0.046) were greatest in Class II average-angle patients. Spongious bone was thinner (p = 0.016) and root apex was closer to the labial cortex in high-angle subgroups when compared to the Class II average-angle subgroup (p = 0.004). Conclusions: Mandibular anterior bony support and lower incisor position were different between average- and high-angle Class II patients. Clinicians should be aware that the range of lower incisor movement in high-angle Class II patients is limited compared to average- angle Class II patients.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.45-54
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• 1986

The establishment and/or registration of an optimal or physiologic relationship between the maxillae and mandible has long been a subject of considerable interest and controversy in dentistry. Centric relation has been generally accepted as a repeatable starting point for restoring the mouth. Recently, it has been claimed that an electronic device (Myo-Monitor) will produce an accurate, reproducible occlusal registration at the vertical and horizontal occlusal position most compatible with the muscular of each patient. The objectives of this study was to compare Myo-Monitor centric to centric relation at the points of reproducibility and anteroposterior, superoinferior position. A Vericheck instrument was employed for examining difference in the position and reproducibility of mandible reproduced by the various check bite records. For this study, 8 dental students and dentists who had no missing teeth and no difficulties of mandibular movement were selected. The following three different positions of the mandible were registered (a) centric relation manipulated by means of chin-point technique with Lucia-jig, (b) centric relation manipulated by means of bilateral technique, (c) Myocentric manipulated by Myo-Monitor. From this experiment, the following results were obtained. 1. Bilateral manipulated centric relation was more reproducible than Myocentric in anteroposterior and superoinferior position , but more reproducible than centric relation manipulated by means of chin point technique with Lucia-jig in anteroposoterior position. Centric relation manipulated by means of chin Point technique with Lucia-jig was more reproducible than Myocentric in right anteroposterior and superoinferior position. 2. Centric relation by means of chin point technique with Lucia-jig was posterior($2.16{\pm}0.78mm$) and superior($0.41{\pm}0.16mm$) to centric occlusion. Bilateral manipulated centric relation was posterior($1.68{\pm}0.10mm$) and superior($1.02{\pm}0.45mm$) to centric occlusion. Myocentric was anterior($0.75{\pm}0.70mm$), inferior($0.59{\pm}0.44mm$) to centric occlusion.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.216-226
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• 2005

The purpose of this study was to test and compare the accuracy and reliability of soft tissue profile predictions generated from two computer software programs (Quick Ceph Image $Pro^{TM}$ (ver 3.0) and $V-Ceph^{TM}$(ver 3.5)) for mandibular set-back surgery. The presurgical and postsurgical lateral cephalograms of 40 patients (20 males and 20 females) were traced on the same acetate paper with the reference taken as the cranial base outline. The presurgical skeletal outlines were digitized onto each computer program and the mandible was moved to mimic the expected surgical procedure with reverence to the mandibular anterior border and lower incisor position of the actual postsurgical skeletal outline. The soft tissue profile was generated and the amount and direction of skeletal movement was calculated with each software. The predicted soft tissue profile was compared to the actual postsurgical soft tissue profile. There were differences between the actual and the predicted surgical soft tissue profile charges in the magnitude and direction, especially the upper lip. lower lip and the soft tissue chin (P<0.05). Quick Ceph had more horizontal measurement errors and thickness errors for the upper lip and lower lip, but V-Ceph had more vertical measurement errors of the lower lip (P<0.05). There was a positive correlation between the prediction errors and the amount of mandibular movements in the vertical position of Sn, the horizontal position of Ls and the upper lip thickness for V-Ceph, and there was a negative correlation in the horizontal position and the thickness of the lower lip for Quick Ceph (P<0.05). However all of the Prediction errors of both imaging softwares were ranged within 3mm, and this was considered to be allowable clinically.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.152-161
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• 2007

This study was conducted to patients visited oral maxillo-facial surgery, KNUH and the purpose of the study was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction treated by skeletal Class III malocclusion patients with open bite versus non-open bite. This retrospective study was based on the examination of 40 patient, 19 males and 21 females, with a mean age 22.3 years. The patients were divided into two groups based on open bite and non-open bite skeletal Class III malocclusion patients. The cephalometric records of 40 skeletal Class III malocclusion patients (open bite: n = 18, non-open bite: n = 22) were examined at different time point, i.e. before surgery(T1), immediately after surgery(T2), one year after surgery(T3). Bilateral sagittal split ramus osteotomy was performed in 40 patients. Rigid internal fixation was standard method used in all patient. Through analysis and evaluation of the cephalometric records, we were able to achieve following results of post-surgical stability and relapse. 1. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in maxillary occlusal plane angle of pre-operative stage(p>0.05). 2. Mean vertical relapses of skeletal Class III malocclusion patients with open bite were $0.02{\pm}1.43mm$ at B point and $0.42{\pm}1.56mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.12{\pm}1.55mm$ at B point and $0.08{\pm}1.57mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in vertical relapse(p>0.05). 3. Mean horizontal relapses of skeletal Class III malocclusion patients with open bite were $1.22{\pm}2.21mm$ at B point and $0.74{\pm}2.25mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.92{\pm}1.81mm$ at B point and $0.83{\pm}2.11mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in horizontal relapse(p>0.05). 4. There were no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in post-surgical mandibular stability(p>0.05). and we believe this is due to minimized mandibular condylar positional change using mandibular condylar positioning system and also rigid fixation using miniplate 5. Although there was no significant relapse tendency observed at chin points, according to the Pearson correlation analysis, the mandibular relapse was influenced by the amount of vertical and horizontal movement of mandibular set-back(p=0.05, r>0.304).

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.652-661
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• 2008

The purpose of this study was to evaluate the skeletal and dental effects obtained by the Frankel functional regulator III in growing children with Class III malocclusions. Cephalometric changes in thirty children at the time of mixed dentition malocclusions (initial mean age, $7.9{\pm}1.1$ years; mean treatment duration, $1.5{\pm}0.8$ years) were analysed. The results were as follows : 1. The skeletal effects on the maxilla showed a significant downward displacement whereas forward displacement was not significant in comparison with the control group. 2. The skeletal effects on the mandible showed statistically significant backward and downward displacement. 3. The dental effects showed statistically significant backward movement in the mandibular incisor tip and increase of overjet The results suggested that forward displacement on the maxilla was insufficient and treatment effects were caused mainly by downward displacement of the maxilla, backward and downward rotation of the mandible, and the increase of overjet during short period.

• The korean journal of orthodontics
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• v.30 no.6 s.83
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• pp.677-685
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• 2000

Anchorage plays an important role in orthodontic treatment. Because of limited anchorage Potential and acceptance problems of intra- or extraoral anchorage aids, endosseous implants have been suggested and used. However, clinicians have hesitated to use endosseous implants as orthodontic anchorage because of limited implantation space, high cost, and long waiting period for osseointegration. Titanium miniscrews and microscrews were introduced as orthodontic anchorage due to their many advantages such as ease of insertion and removal, low cost, immediate loading, and their ability to be placed in any area of the alveolar bone. In this study, a skeletal Class II Patient was treated with sliding mechanics using M.I.A.(micro-implant anchorage). The maxillary micro-implants provide anchorage for retraction of the upper anterior teeth. The mandibular micro-implants induced uprighting and intrusion of the lower molars. The upward and forward movement of the chin followed. This resulted in an increase of the SNB angle, and a decrease of the ANB angle. The micro-implants remained firm and stable throughout treatment. This new approach to the treatment of skeletal Class II malocclusion has the following characteristics . Independent of Patient cooperation. . Shorter treatment time due to the simultaneous retraction of the six anterior teeth . Early change of facial Profile motivating greater cooperation from patients These results indicate that the M.I.A. can be used as anchorage for orthodontic treatment. The use of M.I.A. with sliding mechanics in the treatment of skeletal Class II malocclusion increases the treatment simplicity and efficiency.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.461-477
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• 1998

To evaluate the relapse pattern and long-term stabilities depanding on surgical methods following orthognathic surgery of Cl III patients, the author selected 24 subjects(10 male, 14 female) operated by SSRO and 26 subjects(10 male,16 female) operated by IVRO. Each subject took four lateral cephalograms : just before surgery(T1), within 48hrs after surgery(T2), 4-8 wks after surgery(T3), 6 month or more after surgery(T4), and the landmarks were digitized. The differences of relapse patterns in each interval between two groups were compared and the significance of correlation among the variables of each group was tested. The obtained results are as follows ; 1. Horizontal early relapse was forward movement of mandible in SSRO group, as compared to the backward movement in IVRO group, and there was a statistical significance between the two groups. 2. Vertical early and late relapses were decreases in anterior facial height in both groups and there was no statistical significance between the two groups. 3. There was a statistical significance in negative correlation between mandibular horizontal late relapse and surgical change of articular angle in SSRO group. 4. There was a statistical significance in negative correlation between amount of mandibular set-back and mandibular horizontal early relapse in both groups.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.4
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• pp.731-752
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• 1995

This study was performed to research the changes of masticatory system subsequent to randomly increasing the vertical dimension. The subjects were twenty seven persons, twenty two men and five women, with a mean age of 24.3(age ranged from 22 to 26). The subjects had a complete or almost complete set of natural teeth and reported no subjected symptoms of pain or dysfunction in the masticatory system. The occlusal splint increased vertical dimension was made on semiadjustable articulator. The subjects were randomly divided to three groups according to the vertical dimension, at which the occlusal splint was made. Group I occlusal splints were made at 2mm form the occlusal vertical dimension, group II occlusal splints at 5mm, group III occlusal splints at 8mm. The occlusal splints were almost weared for 2 weeks except meal-time. Clinical examination, muscle activity, changes of free-way space, movement of mandible and articular condyle were recorded and analyzed by means of biopak system(Bioresearch Inc, Millwakee Wisconsin.) and radiograph. 1. In clinical examination, various symptoms were reported by all subjects immediately after the placement of occlusal splint. At the end of experiment, symptoms were lasted by 1 subject in Group I, 2 subjects in Group II, 6 subjects in Group III. At the other subjects, the most of symptoms were disappered within 2-4 days after the placement of occlusal splints. 2. The average free-way space before the startof experiment was 1.77mm in all twenty seven subjects. Immediately after the placement of occlusal splints, 0.67mm at Group I, 0.49mm at Group II, 0.41mm at Group III, At 2 weeks after the placement of occlusal splint 0.93mm, 0.79mm, 0.78mm each other, 1.94mm, 1.77mm, 2.3 mm at immediately after the removal of occlual splint. At 1 week after the removal of occlusal splint, free-way space was recovered to the pre-experimental state 3. In cephalometric radiograph, following either the placement or the removal of the occlusal splints, the movements of mandible in an antero-posterior direction were not statistically significant(p>0.05). 4. In transcranial radiograghs of TMJ, 1 week after the placement of occlusal splint the movement of most superior position on condyle in all group shoed antero-inferior position than before the experiment(p<0.001) and also showed antero-inferior position in mandibular postural rest position than in certric occlusion(p<0.001). Following either the placement or the removal of the splints, the amount of movement of most superior position on condyle was group III. group II and group I in order(p<0.001). 5. In anterior temporal and superficial masseter muscle, muscle activity at postural rest position decreased at 2 weeks after the placement of occlusal splint in group I and group II (p>0.05), but significantly increased in group III(p<0.001). At 1 week after the removal of the occdusal splint, muscle activity at postural rest position was recovered preconditional state 6. In anterior temporal and superficail masseter muscle, muscle activity at clenching in all group was significantly decreased after placement of the occlusal splint, slightly increased during experimental period and recovered to the original state at 1 week after removal of the occlusal splint. But was not statistically significat(p>0.05)s.