• The korean journal of orthodontics
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• v.13 no.2
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• pp.131-146
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• 1983

Faces of normal occlusion, open bite and class III malocclusion were measured using cephalogram in 190 male and female subjects. Using M.K.G., types of mandibular movement, amount of horizontal and vertical movement were studied in relation to occlusal types, and were compared with each other. The following conclusions were obtained. 1. Movement of protrusion was most different in relation to occlusal type. 2. In normal occlusion, maximal protrusion were horizontal 7.66mm, vertical 3.01mm in male, 6.41, 2.92mm respectively in female and maximal inferior position were -24.32, 33.63mm in male,-23.48, 32.27mm respectively in female. 3. Angle between maximal inferior position and horizontal plane were $53.51^{\circ}$ in male, $53.84^{\circ}$ in female. 4. Generally, amount of mandibular movement was greater in male than female. 5. In open bite, path of protrusion was nearly straight without curve $69.2\%$ in male, $70.2\%$ in female. 6. In class III malocclusion, angle and amount of protrusion were smaller than normal occlusion and path was directed anterior-superiorly in $22.7\%$. 7. There was no correlation coefficient between measurement of face and mandibular movement.

• Journal of Oral Medicine and Pain
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• v.22 no.1
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• pp.95-109
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• 1997

The purpose of this research is to investigate the influence on mandibular movements and TMJ sounds with changes of head and neck posture. For the research, twenty patients who had complained of TMJ sounds without any other symptoms of cranio-mandibular disorders, were selected as subjects for measurements of TMJ sounds, and radiographs on transcranial view of TMJ were taken on ten of the subjects. From NHP, UHP, DHP and FHP, aspects of mandibular movement and TMJ sound were investigated from each posture. Aspects of mandibular movement and TMJ sound were observed by measuring total vibration energy(Integral), peak amplitude, maximum amound of mouth opening, and TMJ sound-emitting point using Sonopak for windows (version 1.33) and Bio-EGN(Bioresearch Inc. WI. U.S.A.). Head and neck movement-measuring instrument, CROM(perfomance attainment Inc. U.S.A.) was to maintain even head posture. Degrees of inclination of UHP and DHP were determined at 30' and distance of FHP was 4cm. The results obtained were as follows. 1. Total vibration energy and peak amplitude of TMJ sounds were decreased more on UHP and on UHP and increased more on DHP and FHP than that on NHP. 2. At the maximum mouth opening, distance of TMJ sound-emitting point were decreased more on UHP and increased more on DHP and FHP than that on NHP. 3. The amounts of the maximum mouth opening were increased more on UHP and decreased more on DHP and FHP than that on NHP. 4. For the changes of the head posture with mouth opening observed in radiograph, condylar head was positioned more lower-anteriorly on UHP, and more upper-posteriorly on DHP and FHP than that on NHP. From the results obtained as above, considering positive influence of the change of head and neck posture, avoiding down-head and forward-head posture, and recommending upper- head posture can prevent the progress of temporomandibular disorder and lead to successful treatment for the patients with temporomandibular joint sounds.

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.295-307
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• 1997

This study was performed to investigate the reproductibility of eccentric mandibular movements according to preferred chewing side, range of mouth opening, type of lateral guidance and involvement of temporomandibular disorders. 50 patients with temporomandibular disorders and 65 dental students without any signs and symptoms were randomly selected for this study as the patients group and the control group, respectively. For recording and observation of eccentric mandibular movement trajectory, BioEGN$^\textregistered$ of Biopak$^\textregistered$ system (Bioresearch Inc., USA) was used. Each eccentric movement to anterior, right and left side was performed three times similar to the movement pattern for Pantronic Reproducibility Index. mandibular path was analyzed by three dimensional positional change and the three paths from one direction were compared with one another. From this, reproducibility index of one-directional lateral movement could be calculated, and total reproducibility index, named BioEGN reproducibility index(BERI), was also computed from three-directional eccentric movement likewise. BioEGN reproducibility Index could have four value of score by small or large scale, and by outgoing or incoming movement. The data were analyzed by SAS/stat program and the results obtained were as follows: 1. Right side chewing subjects showed more consistent pattern In reproducibility index in comparison between patients group and control group than left chewing subjects have done, and reproducibility was low in patients group. However, there was no difference between the two stoups in bilateral chewing subjects. 2. There were no difference in reproducibility index between preferred chewing side and contralateral side in unilateral chewing subjects whereas reproducibility index in left side on outgoing movement were higher than in right side in bilateral chewing subjects. 3. Difference in total reproducibility index(BERI) between canine guidance group and non-canine guidance group were not observed though difference in reproducibility index on lateral movement were observed in part. 4. There were no difference in reproducibility index between affected side and contralateral side in unilaterally affected patients, and between unilaterally affected patients and bilaterally affected patients in patients group. 5. Highly significant positive correlationship were shown among the four 쇼pes of total reproducibility index(BERI) in total subjects, and range of clinical mouth opening was negatively correlated with BEBI on outgoing movements and with index on outgoing movement to preferred side.

• Journal of Oral Medicine and Pain
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• v.26 no.2
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• pp.147-156
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• 2001

The purpose of this study was to identify the difference of vertical movement of mandible according to Angle's molar relationship and by skeletal factors affect to vertical movement of mandible. 172(age ranged from 20 to 30) subjects who go to college within territory of Kwangju city without any experience of temporomandibular disorder, extraction and orthodontic treatment. were selected for this study. The subjects were classified into class I(male:30, female:49), class II(male:18, female:24) and class III(male:18, female:33) according to Angle's molar relationship. The distance was measured between incisal edge of maxillary and mandibular central incisor and between bottom of central fossa of maxillary and mandibular 1st molar with ruler. The arch length and width were measured on the diagnostic cast. Cephalometrics were taken and then traced. Landmarks were identified and analyzed. 1. Maximal interincisal opening of male is larger than that of female in class I, class II and class III. Among each group maximal interincisal distance is the largest in class III. Maximal intermolar distance of male is superior to that of female in class I, class II, and class III, but there is no siginficant difference among them. 2. On maximal opening movement of Angle's classification class I and class II, total mandibular length, mandibular ramal length, madibular inferior border length and upper arch width were important variables and facial length, upper arch length and lower arch length had negative relationship to that. On maximal opening movement of Angle's class III, the upper arch length, the lower arch length and anterior facial length were important variables especially when compared with class I and II, and upper arch width had negative relationship. These results suggest that maximal opening movement is affected by facial morphology in all classes, but each group is affected by different facial skeletal variables. Accordingly, facioskeletal variables might be considered as diagnosis and treatment to improve the amount of mouth opening.

• Physical Therapy Korea
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• v.26 no.3
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• pp.99-105
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• 2019

Background: Although magnetic resonance imaging is accurate, it is expensive to measure the movement of temporomandibular joint. The three-dimensional (3D) motion analysis system is an inexpensive measurement tool. Objects: This study examined the reliability of quantifying the mouth opening and lateral mandibular shift and differences between individuals with and without temporomandibular disorder (TMD) using the hygienic method of surface markers on the skin with 3D ultrasound-based motion analysis. Methods: This study included 24 subjects (12 with and 12 without TMD). Temporomandibular joint motion during mouth opening was recorded using two surface markers with 3D ultrasound-based motion analysis. An intraclass correlation coefficient [ICC (3,k)] was used to confirm the intrarater reliability of quantifying kinematic temporomandibular joint motion, and an independent t-test was used to evaluate differences in maximal mouth opening and lateral mandibular shift between the two groups. Results: Assessment of mouth opening and lateral mandibular shift showed excellent test-retest reliability with low standard error of measurement. The lateral mandibular shift and opening-lateral mandibular shift ratio were significantly increased in the TMD group during maximum mouth opening (p<.05). However, no significant difference in maximal mouth opening was observed between the groups with and without TMD (p>.05). Conclusion: This hygienic and simple surface marker method can be used to quantify the mouth opening and lateral mandibular shift at the end-range of mouth opening. The TMD group showed an increased lateral mandibular shift movement at the end-range of mouth opening. The lateral mandibular shift movement can be regarded as a symptom in the diagnosis and treatment of TMD.

• 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.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.111-118
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• 2003

I measured the movement range on the hinge articulator and the movement range in an oral. And then I studied to analyze the gap. I got wax records by the movement on the hinge articulator, the movement in an oral and the movement on the hand articulating. I measured the distance of the cusp tips that are close to the mesial direction and the distal direction, the buccal direction and the lingual direction then I compared gaps. As I saw results on data, I knew that the hinge articulator represented the range of mandibular movement restrictively. I could find the decisive contradiction that the sliding movement finished on the hinge articulator although it did not finish in an oral. If the sliding movement does not reappear exactly, it brings a fatal failure to the dental prosthesis. In addition it is impossible that the hinge articulator restores the movement in an oral because the lateral condyle inclination and the horizontal condyle inclination are fixed previously. Therefore dental prosthesisses were made by the hinge articulator, they will interfere with a mastication. I have obtained the following results; 1. The distance of sliding movement on the hinge articulator showed shorter than the distance of sliding movement in oral. This means the increase of cusp inclination of the dental prosthesis that was made on the hinge articulator. Therefore, when the lateral movement occurs in oral, there is a possibility to become the premature as the increase of cusp inclination. 2. The results that were impressed records in oral and impressed records on the hand articulating have many congruities. I think that the simple crown etc. that were made by the hand articulating method except the long span bridge and the free end case that can not measure the vertical dimension exactly can represent similarly the mandibular movement. 3. If we want to represent the mandibular movement similarly, we have to use the articulator that can adjust the horizontal condyle inclination and the lateral condyle inclination at least.

• The korean journal of orthodontics
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• v.47 no.5
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• pp.289-297
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• 2017

Objective: The objective of this study was to analyze the patterns of tooth movements when distalization of mandibular molars using a mini-plate took place. A finite element analysis was applied to analyze patterns of tooth movements. Methods: The model of the mandible and teeth were used to build a finite element analysis model, and a mini-plate was inserted in the mandibular ramus. Two different orthodontic forces were established for displacement of mandibular molars. Orthodontic forces were applied at the level of the bracket and at the level of the cemento-enamel junction in the mandibular canine respectively. Results: Applying orthodontic forces at the level of the cemento-enamel junction resulted in a greater biomechanical bodily movement in distalization of the mandibular molars compared to when the orthodontic forces were applied at the level of the bracket. Applying orthodontic forces to the cemento-enamel junction also resulted in unwanted greater extrusive movements in distalization of the mandibular molars compared to the bracket level. Conclusions: With considering the mode of orthodontic teeth movement, applying different vertical orthodontic forces for distalization of mandibular molars can lead to more effective distalization of teeth.

• Imaging Science in Dentistry
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• v.38 no.4
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• pp.203-208
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• 2008

Purpose : The purpose of this study was to develop a system for the measurement and simulation of the TMJ movement and to analyze the mandibular movement quantitatively. Materials and Methods : We devised patient-specific splints and a registration body for the TMJ movement tracking. The mandibular movements of the 12 subjects with facial deformity and 3 controls were obtained by using an optical tracking system and the patient-specific splints. The mandibular part was manually segmented from the CT volume data of a patient. Three-dimensional surface models of the maxilla and the mandible were constructed using the segmented data. The continuous movement of the mandible with respect to the maxilla could be simulated by applying the recorded positions sequentially. Trajectories of the selected reference points were calculated during simulation and analyzed. Results : The selected points were the most superior point of bilateral condyle, lower incisor point, and pogonion. There were significant differences (P<0.05) between control group and pre-surgical group in the maximum displacement of left superior condyle, lower incisor, and pogonion in vertical direction. Differences in the maximum lengths of the right and the left condyle were 0.59${\pm}$0.30 mm in pre-surgical group and 2.69${\pm}$2.63 mm in control group, which showed a significant difference (P<0.005). The maximum of differences between lengths of the right and the left calculated during one cycle also showed a significant difference between two groups (P<0.05). Conclusion : Significant differences in mandibular movements between the groups implies that facial deformity have an effect on the movement asymmetry of the mandible. (Korean J Oral Maxillofac Radiol 2008; 38 : 203-8)

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.281-295
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• 1994

It is very important for the ideal restorations of anterior openbite patients to record the mandibular movement and to harmonize mandibular movement with other organs in stomatognathic systems. This study was designed to compare the mandibular movement of anterior openbite patients with that of normal bite(Angle Class I) patients, to ascertain which components of mandibular movement have differences between two groups, and to use for occlusal treatment of mandibular movement. Saphon Visi-trainer Model 3(Tokyo Shizaisha Co. Japan) and Denar Pantronic(Denar Corp.,U.S.A.) were used to record mandibular movement. Pantronic survey was peformed by using an arbitrary hinge axis according to manufacturer's direction. Twenty-eight adult who have physiologically normal occlusion(Angle Class I) and are free of TM dysfunction were selected as a control group(Group 1). Fifteen adult who are anterior openbite patient and have not anterior guidance function and have posterior interference at protrusion were selected as a experimental group(Group 2). The results are as follows : 1. There was no statistically significant difference between the average immediate and progressive side shift of anterior openbite patients(0.54mm, $7.57^{\circ}$) and those of normal group(0.49mm, $5.96^{\circ}$). 2. The average protrusive and orbiting condylar inclination of anterior openbite patient$(30.87^{\circ},\;32.27^{\circ})$ were significantly lower than those of normal group$(36.11^{\circ},\;39.04^{\circ})$ (P<0.05). 3. In the results of Visi-trainer recordings, the mean for the maximum protrusion, the maximum laterotrusion, the angle of laterotrusion and the angle of protrusion in the horizontal trajectory between group 1 and 2 did not differ significantly. 4. The mean for the angle of protrusion, the maximum opening in the frontal trajectory, the ICP-RCP(A-P) distance and the angle of protrusion in the sagittal trajectory differ significantly(P<0.05). 5. The significant correlation was found between orbiting condylar inclination and protrusive condylar inclination.