• The korean journal of orthodontics
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• v.24 no.4 s.47
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• pp.945-956
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• 1994

In the past the jaw and occlusal relationship in centric occlusion were merely considered in case of orthodontic diagnosis and treatment planning. As the fact that functional disturbance of the temporomandibular joint may be caused by occlusal interference was recognized, the importance of functional occlusion and centric relation is emphasized today. Known the importance of centric relation, there are various opinions about definition of centric relation and its taking methods. The purpose of this study was to investigate the relative centric condyle position and to compare the reproducibility of the recordings utilizing different centric relation records obtained by different taking methods. The 15 adults with normal occlusion were participated in this study. Every four centric relation records were taken in each of three methods - leaf gauge, Dawson and myomonitor method. Then the relative centric condyle position, the distance between the condylar position in centric occlusion and the position in centric relation and the reproducibility were studied using SAM 2 articulator and mandibular position indicator. The results were as follows ; 1. The trend of condyle position was different depending on centric relation taking methods. 2. The position of condyle in centric relation by leaf gauge and Dawson methods was superior to that by myomonitor method, and the position by myomonitor method was relatively antero-inferior. 3. The distance between the condylar positions in centric occlusion and the position in centric relation was longest in myomonitor method. 4. The reproducibility had little differences in transverse direction among three methods, while leaf gauge method showed the highest reproducibility and myomonitor method did the lowest reproducibility in antero-posterior and supero-inferior direction.

• The korean journal of orthodontics
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• v.44 no.6
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• pp.312-319
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• 2014

Objective: Facial-type-associated variations in diagnostic features have several implications in orthodontics. For example, in hyperdivergent craniofacial types, growth imbalances are compensated by displacement of the condyle. When diagnosis and treatment planning involves centric relation (CR), detailed knowledge of the condylar position is desirable. The present study aimed to measure condylar displacement (CD) between CR and maximum intercuspation in three facial types of an asymptomatic orthodontic population. Methods: The study was conducted in 108 patients classified into three groups of 36 individuals each (27 women and 9 men; mean age, 20.5 years), based on the following facial patterns: hyperdivergent, hypodivergent, and intermediate. To quantify CD along the horizontal and vertical axes, the condylar position was analyzed using mounted casts on a semi-adjustable articulator and a mandibular position indicator. The Student t-test was used to compare CD between the groups. Results: Vertical displacement was found to be significantly different between the hyperdivergent and hypodivergent groups (p < 0.0002) and between the hyperdivergent and intermediate groups (p < 0.0006). The differences in horizontal displacement were not significant between the groups. In each group, vertical CD was more evident than horizontal displacement was. Conclusions: All facial types, especially the hyperdivergent type, carried a significantly high risk of CD. Therefore, the possibility of CD should be carefully evaluated and considered in the assessment of all orthodontic cases in order to accurately assess jaw relationships and avoid possible misdiagnosis.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.2
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• pp.68-78
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• 2016

Recently, digital technology has become increasingly prevalent in the dental clinic. Using a milling machine for clinic, it is possible to produce provisional restoration inside the clinic. This can promote large clinical cases such as full mouth rehabilitation with the help of a tabletop scanner, which is capable of semi-adjustable articulator equipment, and a powerful dental CAD software with excellent user convenience. In this case report, a full-mouth rehabilitation was done with digital technology to a 55 year-old female patient, who has lost vertical dimension through the attrition, and has got inclined occlusal plane with unplanned and repeated dental reconstruction. Through the design and milling of the provisional restoration in the clinic and the duplication of these provisionals by double scanning technique, a good functional and esthetic result could be achieved.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.3
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• pp.223-229
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• 2017

Closed mouth impression technique by using bite tray is preferred for single tooth impression taking. However, for implant impression taking, open mouth impression technique by using single arch tray is generally used whether it is for single implant or multiple implant. Closed mouth impression technique by using bite tray can save time and materials. It also decreases the chance of error occurrence when a model is mounted on an articulator. In this case report, we tried to show a satisfying result of fabricating single implant fixed prosthodontics after bite tray impression taking by using two different copings for closed mouth impression.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.215-221
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• 2015

Treating patients with severely worn dentition often requires comprehensive prosthetic treatments. Oral rehabilitation and long-term stability could be achieved by analyzing the cause of the wear and changing vertical dimension. The temporary restoration procedure is executed and patient's adaptation is evaluated by long-term observation when treatment is accompanied with increasing vertical dimension. In this case, 54 year-old male presented with worn dentition and esthetic dissatisfaction. In oral manifestations, severely worn dentition with attrition and erosion is diagnosed. To evaluate change of vertical dimension, interocclusal rest space, facial appearance, pronunciation, clinical crown length, distance from incisor edge to labial vestibule are evaluated. Consequently, 2.5 mm increase of vertical dimension that based on articulator incisal pin is determined. After 8 weeks stabilization period with temporary prostheses, definitive prostheses are fabricated. After 6 months follow up period, satisfactory outcomes were achieved both in functional and esthetic aspects through this procedure.

• The Journal of the Korean dental association
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• v.48 no.12
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• pp.893-918
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• 2010

This article is purposed of reviewing the development history of Japanese dental devices and instrument, and their related advertisement activities during the Japanese colonized period in Korea in early 20th century. Japanese dental devices and instrument were redesigned to accommodate their ergonomic shape above the simple imitation, and it implies the excessive desires brought them frustrations. The tragic earthquake on Sep. l, 1923, medical insurance law enforcement on Jan. 1, 1927, celebration of "Cavity prevention Day" started on Jun. 4, 1928, and the attack of Manchuria and China by Japan after 1931, all of these historical incidents become the preliminary requirement for the development of dental devices. On Nov. 1, 1937, Japanese government started to control dental materials, driving the campaigns for excluding foreign products and encourging the use of local products. In 1939, Nakajima dental manufacturers used this political and social atmosphere on their advertisement as saying "Our Nakajima's products have no compromise with the short raw materials, but only commitment to our quality". Since after 1940, the price and supply have been strongly under control, and the control group was appeared to manage all of supply and distribution of raw materials, regular price system, and specifications. At last, the Japanese national power were devastated in its production and distribution capacities, and get to the frustrated period. The main advertised dental devices and instruments in Korea during the Japanese colonized period were 1) dental chair, unit and cabinet, 2) dental x-ray, 3) compressors, 4) dental needles, 5) small instrument and carryon medical(emergency) kit, 6) oral hygiene and pyorrhea alveolaris, infrared rays, sunlight lamp, ultrashort wave treatment devices, 7)crown former, electric furnace, casting machine, articulator, electric lathe, and laboratory equipments, etc.

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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• pp.302-307
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• 2017

PURPOSE. This study compared the SCGAs measured in three types of radiographic images (panoramic, CBCT panoramic-section, and CBCT cross-section images) with values measured using the protrusive occlusal record. MATERIALS AND METHODS. SCGAs were measured in 20 patients on a semi-adjustable articulator using the protrusive interocclusal record. Panoramic and CBCT images were obtained. SCGAs were measured on CBCT images in panoramic and cross sections. In all of the radiographic images, SCGAs were measured using the Frankfort horizontal reference line and the mean curvature line. The most-superior and most-inferior points of the curvatures were identified to determine the mean curvature line. Each measurement was performed twice by two operators independently. The data were analyzed by the t-test, Pearson's correlation test, and Cronbach's ${\alpha}$ using SPSS (${\alpha}=.05$). RESULTS. The mean right and left SCGAs were as follows: protrusive occlusal record (30.1 and 30.2 degrees, respectively), panoramic (38.9 and 38.7 degrees), CBCT panoramic sections (35.4 and 36.8 degrees), and CBCT cross sections (35.3 and 36.1 degrees). The SCGAs differed significantly among the groups. The Pearson coefficients for the correlations with the protrusive occlusal record measurements on the left and right sides were as follows: panoramic (0.834 and 0.791, respectively), CBCT panoramic-section (0.918 and 0.837), and CBCT cross-section (0.918 and 0.845) images. CONCLUSION. Strong correlations were found between SCGAs obtained using radiographic images and the protrusive occlusal record.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.192-198
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• 2014

This case is a porcelain laminate veneer (PLV) and all-ceramic crown treatment case on a female patient in her thirties who visited for esthetic improvement. The patient's chief complaint was protrusive and uneven anterior teeth, and she wanted minimum tooth reduction. The patient was in skeletal class II deep bite. Considering this, check bite method was used for mounting on articulator during diagnostic wax-up. Tooth reduction was done using mock-up base on diagnostic wax-up, and the amount of deletion was checked by index. For the accordance of shade, PLVs were restored in prior to all ceramic crown. After using all-ceramic crown, satisfactory esthetic improvement was obtained.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.111-116
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• 2018

In this thesis, the range of motion of the joint was measured using a flexible sensor without using a goniometer, and the measured values were transferred to a smart device. Current range of joint motion measurement is measured by a person using a goniometer. Since the method of measuring by a person is different according to the measuring method and position of the measuring person, it is difficult to make consistent measurement, and an error may occur. The sensor for measurement is a flexible sensor that measures the resistance value that changes according to the movement of the joint. The sensed value can be transmitted to the smart device wirelessly through the ROM sensor node. Also, the sensed analog values were converted to digital values using an ADC. The converted value can be transmitted to the smart device wirelessly through the sensor node. The developed ROM measuring device can perform more consistent measurement than the measurement using general articulator and real time monitoring by interlocking with smart device, so that rapid diagnosis according to the movement of the joint can help the patient's rapid treatment and rehabilitation medical advancement will be.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.6
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• pp.560-571
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• 2002

Jaw relations and the recording methods have been controversial aspects of dentistry. The purpose of this study was to quantify the relative muscle activity of the masseter and temporal muscles in relation to different intermaxillary relations recorded by intra-oral tracer during maximal clenching and to decide the optimal mandibular position. Ten volunteers with healthy TMJ were studied. Intra-oral tracer was assembled and bite block was fabricated in the articulator. Intra-oral tracer was placed in the mouth, and four mandibular positions were recorded. EMG activity was recorded on a BIO-PAK system (Bio-Research Associates, Inc. USA.) in masseter and temporal muscle and compared in each mandibular positions. The results were as follows: 1. In comparison with maximum intercuspation, the chewing position was the most similar followed by tapping position, myocentric position and posterior border position. However the differences were not statistically significant. 2. In comparison of bilateral symmetry of masseter muscle, tapping position was the most symmetrical followed by chewing position and maximum intercuspation. Myocentric position and posterior border position were not symmetrical. (P<.05). 3. In comparison of bilateral symmetry of anterior temporal muscle, chewing position was the most symmetrical followed by posterior border position, maximum intercuspation, myocentric position and tapping position. However the differences were not statistically significant. 4. In comparison of proportionality of anterior temporal muscle to masseter muscle activity on left side, posterior border position was the greatest followed by myocentric position, taping position, chewing position and maximum intercuspation. And the proportionality of posterior border position was greater than that of maximum intercuspation. (P<.05). 5. In comparison of proportionality of anterior temporal muscle to masseter muscle activity on right side, myocentric position was the greatest followed by posterior border position, tapping position, maximum intercuspation and chewing position. However the differences were not statistically significant.