• 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 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 Journal of Korean Academy of Prosthodontics
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• v.26 no.1
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• pp.133-151
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• 1988

The objectives of this study were to compare the position of centric relation guided by means of leaf gauges, bilateral manipulation, chin-point guidance with Lucia jig and self-guided method and the reproducibility, respectively. A Veri-check (Denar Co., Anaheim, California) was employed for examining, and the displacement of position and reproducibility were verified. The following results were obtained. 1. On the sagittal plane, the centric relation guided by means of leaf gauges showed greater posterior displacement than that by means of bilateral manipulation and less than that by means of chin-point guidance with Lucia jig, and self-guided centric relation showed least posterior displacement. The centric relation guided by means of bilateral manipulation showed greater superior displacement than that by means of chin-point guidance with Lucia jig and less than that by means of leaf gauges and self-guided centric relation showed least superior displacement. 2. On the horizontal plane, the centric relation guided by means of chin-point guidance with Lucia jig showed greater posterior displacement than that of bilateral manipulation and less than that leaf gauges, however the self-guided centric relation showed slightly anterior displacement. 3. The anteroposterior displacement measured on sagittal plane and horizontal plane were highly correlated. (p<0.05). 4. The reproducibility of centric relation guided by means of leaf gauges, bilateral manipulation and chin-point guidance with Lucia jig were similar and more reproducible than self-guided centric relation.

• The Journal of Korean Academy of Prosthodontics
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• v.18 no.1
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• pp.73-86
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• 1980

Recently, the controversy continues as to whether maximum intercuspation of teeth should occur at the terminal hinge position(the condylar theory) or at the myo-co(the neuromuscular theory). There is also much controversy regarding the antero-posterior position of myo-co. The object of this study was to measure and compare with the positional relations of centric relation, centric occlusion and myo-co, and free-way space using Mandibular Kinesiograph and Myo-monitor in the 40 subjects without stomatognathic problems. Mandibular Kinesiograph(M.K.G.) was originally conceived as a research instrument to track mandibular movement and position. As its use in research progressed, its great diagnostic value became apparent in case by case. And Myo-monitor was developed as a means of applying the neuromuscular approach to occlusion. Thus the Myo-monitor technique is an intra-systemic approach to occlusal positioning using patient's own musculature, and Myo-monitor is used to relax the musculature by a light myopulse induced electronically. From this experiment, the following results were obtained. 1. The adaptive free-way space before muscle relaxation was an average of $1.6{\pm}60mm$, and the true free-way space after muscle relaxation using Myo-monitor was an average of $2.4{\pm}0.74mm$. 2. It took an average of $25{\pm}3.11$ minutes to relax the mandibular musculature by Myo-monitor and administration of 5mg. Diazepam and an average of $38{\pm}4.73$ minutes by Myo-monitor without administration of Diazepam. 3. Myo-co existed anterior to centric occlusion, with an average of $0.53{\pm}0.31$ mm, and centric relation existed posterior to centric occlusion, with an average of $0.57{\pm}0.58mm$ before muscle relaxation and with an average of $0.57{\pm}0.43mm$ after muscle relaxation. 4. Centric relation coincided with centric occlusion in 5 of 40 subjects(12.5%), and posterior to centric occlusion in the rest of cases (87.5%). 5. Myo-co existed anterior to centric occlusion in 38 of 40 subjects(95%), except 1 subject that coincided with centric occlusion and 1 subject that existed posterior to centric occlusion. 6. Myo-co and centric relation existed inferior to centric occlusion and the lateral displacement was various with individual difference. 7. The total displacement from centric occlusion to centric relation was an average of $0.74{\pm}0.64mm$ before muscle relaxation, and an average of $0.68{\pm}0.53mm$ after muscle relaxation, and the total displacement from centric occlusion to myo-co was an average of $1.07{\pm}0.58mm$.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.591-601
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• 1991

To determine the difference in cephalometric measurements between centric relation and centric occlusion, 60 patient-20 patients for each malocclusion group-were examined with the cephalograms in centric relation and in centric occlusion. The results are as follows: 1. There are differences in cephalometric measurements with the mandible in the two different position, and some measurements are statistically significant. 2. No clinically useful prediction may be made from cephalometric radiographs concerning the amount of mandibular deflection from centric relation to centric occlusion. 3. If, the large differences in the cephalometric measurements with the mandible in the two different position, the analysis with the cephalogram in centric occlusion is needed to be compensated with the other clinical approach.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.16 no.1
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• pp.69-79
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• 1986

The purpose of this investigation was to know correlation of mean values between centric occlusion and centric relation by the cephalogram in Angle's Class Ⅰ and Ⅲ malocclusion subjects. 22 adults with Angle's Class Ⅰ malocclusion (17 men and 5 women, 21 to 27 years of age) and 14 adults with Angle's Class Ⅲ malocclusion (10 men and 4 women, 21 to 27 years of age) were selected from the dental students in Yonsei University. Each subject was given two lateral cephalometric radiographies and cephalometric analysis was performed. All data from these analyses was recorded and statistically processed with CYBER computer system. 1. The results were obtained as follows: There was a strong positive correlation between centric occlusion and centric relation in all subjects with Angle's Class Ⅰ and Ⅲ malocclusion. 2. In Angle's Class Ⅰ malocclusion, measurements in lower facial height revealed significant difference between centric occlusion and centric relation (P<0.05). In Angle's Class Ⅲmalocclusion, measurements in facial axis angle, mandibular plane angle, convexity of A point, lower incisor protrusion, lower facial height revealed significant difference between centric occlusion and centric relation (P<0.05). 3. When the mandible was moved from centric occlusion to centric relation, the mean distance of mandibular movement was 1.27㎜ (0.2-2.8㎜) in Angle's Class Ⅰ malocclusion, 1.70㎜ (0.55-4.15㎜) in Angle's Class Ⅲ malocclusion, and 1.44㎜ (0.2-4.15㎜) in all subjects.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.12 no.1
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• pp.15-20
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• 1982

The purpose of this study was to investigate the normal range of condylar displacement of normal adults. The author has observed two roentgenographic images of condylar head taken by transcranial projection. Two roentgenographic images are centric occlusion and centric relation. The results were obtained as follow: 1. Total subjects are 72 condyles. The condylar displacement from centric relation to centric occlusion was shown in 65 condyles (90%) anteriorly. 59 condyles (82%) inferiorly. Two condyles (3%) showed neither anterior displacement nor inferior displacement. 2. The average displacement of right condyles was 0.54±0.06㎜ anteriorly, 0.34±0.05㎜ inferiorly. The average displacement of left condyles was 0.74±0.09㎜ anteriorly, 0.45±0.05㎜ inferiorly. 3. The subjects of synmetrical displacement are 7 cases (20%) anteriorly, 2 cases (6%) inferiorly.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.366-376
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• 2015

The Gothic arch tracing method using a Gothic arch tracer which is one of the centric relation recording methods can reproduce mandibular movement more accurately by describing the path of mandibular curvilinear motion. This case reports that we have satisfactory results by recording reproducible centric relation using a gothic arch tracing method in a patient who has difficulty to induce centric relation by operator due to parafunctional movement.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.4
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• pp.275-282
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• 2001

Centric relation is defined the horizontal position between maxilla and mandible when condylar head of mandible is positioned adequately in mandibular fossa. The most recent concept of centric relation position is defined as the mandibular position in which the condyles are in their most superoanterior position in the articular fossa, resting against the posterior slope of the articular eminences, with the articular disk properly interposed. To be suitable as a reference point during occlusal management, a mandibular position of centric relation has to be functionally acceptable to the patient and clinically reproducible and achievable during everyday practice. There are numerous methods for determination of centric relation, and in this study we used three of them, Gothic arch tracing(Group I), leaf gauge(Group II), and anterior jig(Group III). The subjects were 10, 8 men and 2 women, age-ranged from 23 to 26 years old, had no prosthetics in thier mouth, and had no sign and symptom of temporomandibular disorders. We gained three occlusal records using each method, and then the degree of the reproducibility was examined with split cast technique. In this study the reproducibility of centric relation using split cast technique was greater in the order of Group I(mean 1.6), Group II(mean 1.4), and Group III(mean 1.3), but there was no significant differences among them statistically(p>0.05).

• The korean journal of orthodontics
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• v.22 no.1
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• pp.89-107
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• 1992

The purpose of this study was to investigate the difference between normal and malocclusion subjects in Temporomandibular joint. This study was based on the 44 subjects with normal occlusion, 30 subjects with Class II malocclusion, 30 subjects with Class III malocclusion before treatment. After submental vertex view analysis, each subject was given the TMJ Tomogram in centric relation and centric occlusion and the Cephalogram was taken with Quint Sectograph. The TMJ spaces were measured and analyzed statistically. Following results were obtained. 1. When centric relation was compared to centric occlusion, The condyles were positioned more posteriorly and superiorly in centric relation position of the normal occlusion group and the class II malocclusion group. In the Class III malocclusion group. There was no significant difference in the condylar position between centric occlusion and centric relation. 2. The condyles of the Class III malocclusion group were positioned more superiorly than the normal occlusion group and the Class II malocclusion group. 3. In the correlation between articular eminence posterior slope angle and lingual slope angle of the upper anterior central incisor, there was significant correlation in the normal occlusion group. But no significant correlation was found in the malocclusion group. 4. The mean value of the horizontal angulation of condylar head to the transear rod axis plane was $20.32^{\circ}{\pm}8.12^{\circ}$ in the normal occlusion group, $25.08^{\circ}{\pm}4.83^{\circ}$ in the class II malocclusion group, $14.68^{\circ}{\pm}4.08^{\circ}$ in the class III malocclusion group.