• 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.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.1
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• pp.37-49
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• 2000

It was clinically important to substitute the physiologic centric relation to the therapeutic position of the patients who needed the oral rehabilitation or occlusal treatment. There were several methods for recording the centric relation. One of the known methods was to use the gothic arch tracer. However the existing intraoral device was difficult to adjust the three dimensional angulation of the recording plate and recording stylus depending on the hinge movement arch of the individual. The purpose of this study was to develop new intraoral tracer which had adjustable stylus within hinge movement arch for the record of centric relation and to evaluate the clinical application of this device. The results were as follow; 1. A stylus of new developed intraoral tracer was so adjustable that the recording of mandibular positions could be reproducible within the hinge movement arc. 2. A record plate of new developed intraoral tracer was so adjustable to parallel with the occlusal plane that lateral recording of mandibular position was able to obtain stably. This study showed that new developed intraoral tracer allowed the determination of the treatment position which can be used in the full mouth rehabilitation and occlusal treatments.

• Journal of Yeungnam Medical Science
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• v.39 no.4
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• pp.341-343
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• 2022

To determine the vertical dimension and centric relation during the construction of implant overdentures, the record base and wax rim may need to be adjusted. The conventional method has several drawbacks, as it requires repeated tightening and loosening of the impression coping. Here, we report a useful and novel method for interocclusal records using the healing abutments in implant overdentures. Our case demonstrates that this method is easier and simpler and prevents gingival collapse.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.3
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• pp.238-245
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• 2014

In order to create denture occlusion that is functional, comfortable and balanced, it is necessary to both determine a vertical dimension of occlusion that is in harmony with the patient's musculature and to record a relatively repeatable jaw relation position. This require clinical skill to establish an accurate, verifiable and reproducible vertical dimension of occlusion (VDO) and centric relation (CR). Correct vertical relation depends upon a consideration of several factors, including muscle tone, inter-dental arch space and parallelism of the ridges. Centric relation is considered to be a repeatable position from which all opening and lateral mandibular movements begin and recording this position is a critical step in the fabrication of dentures. Any errors made while taking maxillo-mandibular jaw relation records will result in denture that are uncomfortable. The purpose of this paper is to review a very simple and efficient technique for accomplishing these two important steps in denture fabrication.

• Journal of Oral Medicine and Pain
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• v.12 no.1
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• pp.85-93
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• 1987

The author studied on the effect of TMJ sounds to the patterns and ranges of mandibular border movements in horizontal plane with Pantograph (Denar Corp.). For study, 19 patients with TMJ sounds only and 16 students with no TM disorder were selected and classified as experimental group and control group, respectively. The subject performed right lateral movement, left lateral movement, and forward movement. Each movement were performed 3 times and the movement trajectory obtained with mechanical pantograph were observed for accordance of centric relation position, reproducibility and/or restriction of lateral movement paths, deviation of protrusive path in anterior table, restriction of protrusive condylar movement path in posterior horizontal table, presence of Fisher angle in posterior vertical table. And pantographic reproducibility Index (PRI) were obtained with pantronic by the same movement method as in the mechanical pantograph record. The obtained results were as follows : 1. In experimental group, PRI scores in those who show accordance of centric relation position were 14.4, and were 26.53 in those who did not show accordance of centric relation position. However, the PRI scores of the two subgroups show no statistically significant difference in control group. Therefore, in experimental group, the capability of accordance of centric relation position affected largely the PRI scores than in control group. 2. Deviation of protrusive path was opposite to the affected side in experimental group, and was left side in control group. 3. Restriction side of condylar movement in protrusion was ipsilateral to the deviation side in experimental group, but in control group, restriction side was not related to the deviation side. 4. PRI scores in experimental group were 23.2 (moderate dysfunction category), and in control group, were 17.8 (slight dysfunction category). The PRI scores in control group, however, implies that the evaluation of temporomandibular disorders by the PRI scores only may be unreasonable.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.2
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• pp.115-124
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• 2003

One of the important things in the full mouth reconstruction is the determination of therapeutic position. Centric jaw relation is used as a therapeutic position for the full mouth reconstruction. There are several techniques associated with recording this position. Five clinically acceptable techniques are as follows: 1) Swallowing or free closure, 2) Chin point guidance, 3) Bimanual method 4) Myo-monitor technique, 5) Anterior deprogrammer. Centric relation obtained utilizing the anterior acrylic resin platform in this case. Another important thing in full mouth reconstruction is provisional restoration. Provisional restorations are an excellent diagnostic instrument, especially in full remain esthetics, phonetics, function, parafunction, and dysfunction after evaluation and acceptance through clinical trial with the provisional restorations should be accurately transferred to the final restorations to ensure the same clinical success. Especially, anterior guidance should be accurately transferred to the final restorations. An accurate anterior guidance is critical for optimal esthetics, phonetics, comfort, function, stress minimization, and longevity of teeth and restorations. To record optimum anterior guidance, customized anterior guide table is used in this case. Considering previously mentioned points, we did successive treatment. And it resulted in a better situation esthetically and functionally. Followings are what we cared in treating a patient in this case. 1) Accurate centric relation recording 2) Accurate transference of anterior guidance to the final restorations.

• Journal of Oral Medicine and Pain
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• v.13 no.1
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• pp.43-52
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• 1988

The author studied masticatory muscle activity and bite force in normal persons without Temporomandibular Disorders(TMD) signs and symptoms, The number of subjects was 15, and the age of them was from 22 to 25 years. Electromyography was used to record the muscle activity in tapping and clenching movement with or without occlusal splint. 3 splints were made from 3 different mandibular position, that if, centric occlusion position, Rocabado's mandibular rest position, Dawson's centric relation position. The thickness of splint was 3.0-3.5㎜ at molar region. The muscle examined were Masseter and Anterior Temporalis attached with surface electrodes and the device used to measure the EMG level was Bioelectric processor Model EM2. After recording the EMG, the author measured the bite force level in clenching movement with bite force meter Model MPM-3000 in the dame position used in the EMG experiment. The obtained results were as follow : 1. With occlusal splints insetion, the amount of decreased muscle activity in Anterior Temporalis was more than those in Masseter. 2. In the three maxillomandibular relationships with occlusal splints, Masseter showed slightly increased level of muscle in centric occlusion but Ant. Temporalis showed decreased level of muscle activity reversely in that position. 3. Muscle activities between Rocabado's rest position and Dawson's centric relation position were generally similar whatever the muscles or the movements the author examined. 4. Bite force in clenching movement increased with splints insertion, especially with the splint registered in centric occlusion position.

• Journal of Oral Medicine and Pain
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• v.18 no.2
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• pp.71-79
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• 1993

Many types of occlusal splints are used for treatment of craniomandibular disorders. Most widely used splint among them is flat-type centric relation splint. Insertion of splint into the mouth may cause increasing of vertical dimension, masticatory muscle realignment and rearrangement of maxillo-mandibular relationship, so as a result of splint treatment, occlusal relation may vary whether you like it or not. From this point of view, occlusal state of patient shold be frequently monitored to prevent undesired or harmful effect during occlusal splint therapy. The purpose of this study was to investigate the effect of occlusal splint, especially centric relation splint, on the occlusal contact state after 3 months treatment. 32 patients with craniomandibular disorders who had unilateral symptoms participated in this study. To observe and record occlusal contact state, the author used T-Scan system (Tekscan Co. U.S.A.) at both pretreatment and posttreatment. The recorded date were analyzed with regard to contact number, contact force and contact time, change of anterior tooth contact and coincidence of first contact point with affected side were observed, too. Aan last, the subjects were divided into 2 groups and compared, according to average value of VAS index, with respect to joint pain, sound and limitation of movement, respectively. The collected date were statistically processed with SPSS and the result as follows : 1. Total occlusal contact number and force were not changed by occlusal splint therapy but total occlusal contact time decreased slightly. 2. There was a tendency of increasing number of subjects with anterior tooth contact after treatment and change of first contact point side were observed in as many as 40.6% of subjects. 3. There were no difference between higher and lower group of VAS index, and between pretreatment and posttreatment in each group, either.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.4
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• pp.451-457
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• 2017

Bell's palsy is an acute-onset unilateral peripheral facial neuropathy. For patients with sequelae of facial paresis, the successful rehabilitation of fully edentulous arches is challenging. This case report described the treatment procedures and clinical considerations to fabricate complete dentures of a patient who showed unilateral displacement of mandible, unilateral chewing pattern and parafunctional jaw movement due to sequelae of Bell's palsy. Gothic arch tracing was used to record reproducible centric relation and lingualized occlusion was performed to provide freedom to move between centric relation and the patient's habitual functional area in fabricating satisfactory dentures in terms of function and esthetics.

• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.125-146
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• 1990

The relationale for recording mandibular movement is to accurately adjust an articulator. Techniques to record mandibular movement include radiographic interpretation, extraoral tracing, and intraoral recording materials. This study was performed to compare the concylar guidance inclination and Bennett shift(immediate & progressive side shift)obtained by using an electronic pantograph, pantograph and wax interocclusal records in Korean. Ten adults who have normal occlusion and are free of TMJ dysfunction were selected and clutches were constructed. At first Pantronic survey was performed three times by using an kinematic hinge axis according to manufacturer's direction. Next pantographic survey was performed three times and the articulator was adjusted with each pantographic recording. And then maxillary cast was attached to the articulator with pantographic as a face-bow and the mandibular cast was mounted to the articulator with centric relation record. Three protrusive, three left lateral and three right lateral wax interocclusal records were taken on the subjects and the articulator was adjusted with each interocclusal record. Protrusive condylar inclination, lateral condylar inclination, immediate side shift and progressive side shift obtained by using electronic pantograph, pantograph and wax interocclusal record were compared and analized. The results were as follows; 1. The average left and right protrusive and orbiting condylar inclination($33.7^{\circ},\;37.1^{\circ},\;40.6^{\circ},\;43.5^{\circ}$) record with Pantronic was significantly greater than that recorded with other methods. 2. The average left and right protrusive and orbiting condylar inclination($24.8^{\circ},\;27.0^{\circ},\;31.4^{\circ},\;32.4^{\circ}$)recorded with wax interocclusal record was less than that of other methods. 3. The average left and right immediate side shift(0.57mm,0.44mm)recorded with wax interocclusal record was greater than that of other methods and the average left rigtht immmediate side shift(0.30mm,0.41mm)recorded with Pantronic was significantly greater than that recorded with pantograph(0.11mm,0.20mm). 4. The average variance of wax interocclusal was signivicantly higher than that of other methods.