• Journal of Oral Medicine and Pain
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• v.21 no.2
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• pp.383-392
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• 1996

An observation and evaluation of the reproducibility of the mandibular movements has been a integral part of a test for mandibular function and dysfunction. After Pantographic Reproducibility Index(PRI) was introduced in dentistry, many authors have used the index for investigation of mandibular movement function, especially in condylar compartment. Howerer, the difficult and time-consuming work of instrumentation for getting the PRI has been a major obstacle in using pantograph. This study was performed to try a new mandibular reproducibility index, so-called BioEGN reproducibility index(BERI), calculated from mandibular trajectory recorded with BioEGN. 26 dental students without any signs and symptoms of temporomandibular disorders and 22 patients with temporomandibular disorders took part in this study and classed to control group and patients group, respectively. Pantronic and BioEGN were used to record and calculate the indices, PRI and BERI. PRI had only one value, but BERI had two values of outgoing and incoming movement in each scale. With two scales of small and large, as a result, BERI had four values in this study. PRI corresponded to BERI in small scale on outgoing total movements. The data were calculated and analyzed with SAS/stat program and the conclusion of this study were as follows : 1. In every scales, in each movement, BERI on outgoing movement in control group was lower than that in patients group, respectively, but BERI on incoming movement was only different in one side movement, that was, left excursion. 2. The difference between BERI on outgoing movement and BERI on incoming movement was only shown in small scale on total movements, not in each movement, in control group. However, there was generally a positive correlationship between BERI on outgoing movement and BERI on incoming movement in each movement in both groups. 3. Simple statistics of PRI was similar to that of BERI on total movements in small scale, but there was a negative correlation between PRI and BERI on total movements in large sclae only in patients group.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.337-345
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• 1994

Arthrography of the temporomandibular joint is a useful method of demonstrating the soft tissue abnormalities related to disc dysfunction. In this study, 19 asymptomatic joints, 31 joints with anterior disc displacement with reduction, 31 joints with anterior disc displacement without reduction which were classified by arthrotomography under fluoroscopy were evaluated to determine the linear measurement of anterior recess of inferior joint space and the relationship between the condylar anterior translation and the severity of the internal derangements. Their fluoroscopic images were also evaluated to describe the characteristics of condylar paths in internal derangements of the temporomandibular joints. The results were as follows; 1. The mean lengths of the anterior recess in asymptomaic group. reduction group. and non-reduction group were 8.7±1.6㎜. 11.2±1.7㎜, 12.8±1.7㎜ respectively. The length of the anterior recess was increased according to the severity of the internal derangements(P<0.05). 2. Linear measurements of anterior movement of condyle on maximum mouth opening were 13.1 ±4.2㎜, 15.9±4.1㎜, 5.0±3.7㎜ in asymptomatic group. reduction group, and non-reduction group respectively. Compared with asymptomatic group, reduction group showed hypermobolity of the condyle and non-reduction group showed hypomobility. 3. Condyles moved beyond the crest of articular eminence in 80% of reduction group and did not reach it in 70% of non-reduction group. 4. The condyle moved mainly superiorly in reduction group(66%) and horizontally in asymptomatic group(47%). There were no cases to move superiorly in non-reduction group.

• The Journal of the Korean dental association
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• v.22 no.7 s.182
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• pp.607-620
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• 1984

The validity of the Kinesiegraph (MHG-5R) output was studied using a non-ferromagnetic positioning device within working range of a 3 cm wide by 4 cm deep by 5 cm high three dimensional lattice. To determine how well observed values of the M K G outputs may predict case values of actual measurements, relationships between those values were tested by viewing scatter plots and correlation between observed values and actual values. In order to devise some form of served values of the M k G outputs (volts), statistical regression analysis was performed. The statistical analysis showed that observed values and actual values were strongly correlated. However, high correlation does not necessarily mean perfect predictability of given linear models. The formulated models were not able to predict all of acutal values this is partly 엳 새the discreteness of dependent variables (actual values) and also is because of independent nature of observed values. In conclusion, unless the Kinesiograph is suitably modified, the inherent nonlinearity characteristic of the system output limits its application to the measurement of a limited range of jaw movements.

• The Journal of the Korean dental association
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• v.22 no.7 s.182
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• pp.621-633
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• 1984

The possibility of expanding the linear range of the Kinesiograph was studied using a nonferromagnetic mechanical positioning device. The magnet was moved in linear steps of 5 mm through three planes parallel to the frame work carrying the sensors within working range of a 3 cm wide by 4 cm deep by 5 cm high three dimensional lattice and a matrix of 693 data points was achieved. For each data point, the three Kinesiograph outputs were associated with the values of actual position. Once three coordinates of observed values were known, actual values could be determined. A computer program was specially written in Fortran to deal with this work. Because each dat point was 5 mm apart from each other, there would be 480 cubes with 8 data points Further refinement of the system is possible using a smaller interval between each data point. In conclusion, a theoretical model was presented which, by means of computer support, would allow the absolute measurement of jaw position over the entire range of functional jaw movements.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.105-116
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• 1986

In order to determine if a relationship exists between the clinical symptoms of TMJ dysfunction and the reproducibility of mandibular movements, twenty one subjects were chosen. The control group consisted of 5 subjects who were determined to be free from signs and symptoms of dysfunction . The sixteen experimental subjects were selected on the basis of their having dysfunctional symptoms. The author obtained two sets of pantographic tracings. Each set consisted of tracings from three both lateral and one protrusive movements. A second set of tracings were recorded immediately on the new recording papers using the same procedure as the first tracing. The tracings were scored by Pantographic reproducibility index (PRI). The obtained results were as follows. 1. Mean PRI scores of groups increased as the degree of dysfunction were increased. 2. For the groups of no or slight dysfunctional symptoms the PRI scores of the second tracing were smaller than the first one, wherea the scores of the second tracing from $D_2,\;D_3$ group were larger than the first tracing. 3. Differences between the mean PRI scores of control group and those of experimental group were statistically significant. 4. The second sets of tracings were more reliable statistically than those of first ones. 5. PRI can be used as a meaningful aid for the evaluation of the diagnostic and therapeutic results of treatment modalities for the TMJ dysfunction. 6. At 3east two sets of tracings should be recorded when the PRI is to be used to detect the incoordinated movements of TMJ dysfunction patient. 7. PRI scores of control group ($D_0$) was 137.7, thus, mandibular movement was reproducible, whereas PRI scores of experimental groups ($D_1,\;D_2,\;D_3$) were 22.5, 27.7, 30.45 respectively, thus were nonreproducible.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.1
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• pp.55-81
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• 1989

Recently the instantaneous center concept has been to understand the biomechanics by which a tissue derangement causes a mechanical derangement in human joint. Therefore, to understand the biomechanics of temporomandibular joint (T.M.J.) as a part of human joint, it is necessary to clarify the instantaneous center of rotation (I.C.R.) in the mandibular movement. Twenty male subjects without T.M.J. disorder and mandibular deviation during the mandibular movement were selected for this study. The habitual opening and closing paths were recorded on the paper of the sagittal metal plate by two pencil markers connected to the resin open clutch attached on the lower teeth, which was designed for this study. The coordinates of the 33-target points and the 109-anatomical landmarks were obtained using a Summagraphic digitizer connected to a 18AT computer. The original raw data of the opening and closing paths were smoothed by B-spline curve fitting technique and then the I.C.R. pathways were determined mathematically by the computer using algorithm for finding the I.C.R. of a planer rigid body model. Also the opening and closing movements of the mandible were simulated according to the determined I.C.R. The results obtained from this study were as follows. 1. At the early opening and the last closing, I.C.R's were almost distributed around the mastoid process outside the mandibular body without the presence in the region of the mandibular condyle. 2. The I.C.R. pathway showed variable patterns to each subject at the opening and closing movements. 3. The K constant with uniform pattern was obtained by the rotation angle times the radius, which was assumed to the index of the mandibular movement. 4. The opening and closing movements of the mandible were simulated by the I.C.R. pathways at the habitual opening and closing movements. 5. The mandibular condyle was rotated or translated accordng to the relative rotation angle and radius of the determinant factors of K contant.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.195-201
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• 2022

Hemimandibulectomy and free fibular flap (FFF) in patients with squamous cell carcinoma could disturb the functional movement of the mandible. The muscular function in the sectioned side was compromised because of the incompetency of the muscle attachment to the mandible, leading to the unstable occlusal contact in the centric and eccentric occlusion. In this report, we present a case of a 63-year-old male who underwent cancer surgery and reconstruction with fibular graft, and he needed a fixed dental prosthesis to restore tooth loss in the anterior region. Occlusal contact change and instability were found according to the bite force in the centric relation and eccentric movement. This case report aimed to present the prosthetic procedure for fabricating the functionally optimized fixed prosthesis wherein the functionally generated path (FGP) technique and digital imaging method were applied to replicate mandibular movement and vertical dimension of the patient.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.3
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• pp.168-175
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• 2023

Long-term use of inappropriate prosthesis often results in habitual closure or irregular mandibular movements. In that case, guide to the stable centric position is difficult. Therefore, by using a treatment denture, the muscles and TMJ should be stabilized and the jaw relation should be acquired with the treatment position. Compared to the conventional method, digital technology in fabrication complete denture has the advantage of reproducing a stable tooth arrangement in cases of difficult tooth alignment, minimizing laboratory errors and reducing denture fabrication time. Therefore, in this case, the final denture was fabricated by digitally reproducing the stable treatment position, vertical dimension, and lip support with a treatment denture, and satisfactory results were obtained.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.2
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• pp.169-178
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• 2010

Objective. This study was conducted to observe the effect on appendage muscle strength according to increase in occlusal vertical dimension. Materials and methods. Ten males with a mean age of 21 were selected. The tested occlusal splints were made at the position of increased occlusal vertical dimension of 2mm,3.5mm and 5mm from the intercuspal position. Before and after wearing occlusal splints, the appendage muscle strength were tested by Cybex II dynamometer (Lumex Inc., Ronkonkoma, NY, USA). Results. Statistical analysis using the paired t-test revealed significant differences for flexion and extension of the hip, pronation of the forearm, internal rotation of the shoulder, external and internal rotation of the knee, and dorsiflexion and plantarflexion of the ankle (p<0.05). Conclusions. As the result of this study, we conclude that when occlusal vertical dimension was increased, most of mean muscular strength values were increased. Especially at the position of 3.5mm increased vertical dimension displayed the highest mean muscular strength value than other positions.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.2
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• pp.157-168
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• 2010

Many athletes have been using occlusal stabilization appliances to improve their performance. Few studies have examined the benefits of such an appliance in golf. We determined the effect of such appliances on the masticatory muscle activities and driving distances of professional golf players. The appliances were customized for each player and adjusted using a computerized device. The electromyographic muscle activities and driving distances with and without the appliance were measured and compared using the K7 Analyzer and the GolfAchiever II assembly. A paired t-test was used for statistical analysis. The muscle activities of the temporo-frontal and masseter muscles with the appliance were significantly more stable than those without the appliance, and the driving distances with the appliance were significantly different from those without it. Although there were intra-individual differences, professional golf players with temporomandibular disorders showed a greater improvement in performance.