• The korean journal of orthodontics
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• v.54 no.5
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• pp.325-341
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• 2024

Objective: To correlate temporomandibular joint (TMJ) morphology and position with cone-beam computed tomography (CBCT) images, Joint Vibration Analysis (JVA), and Jaw Tracker (JT) to develop a radiation-free, dynamic method for screening and monitoring the TMJ in orthodontic patients. Methods: A total of 236 orthodontic patients without symptoms of TMJ disorders who had undergone CBCT were selected for the JVA and JT tests in this cross-sectional study. TMJ position and morphology were measured using a three-dimensional analysis software. JT measurements involved six opening-closing cycles, and JVA measurements were performed using a metronome to guide the mouth opening-closing movements of the patients. The correlations among the three measuring devices were evaluated. Results: Abnormalities in condylar surface morphology affected the mandibular range of motion. The cut-off value results show that when various measurement groups are within a certain range, abnormalities may be observed in morphology (area under the curve, 0.81; P < 0.001). A 300/< 300 Hz ratio ≥ 0.09 suggested abnormal morphology (P < 0.05). Correlations were observed among the maximum opening velocity, maximum vertical opening position, and joint spaces in the JT measurements. Correlations were also observed between the > 300/< 300 Hz ratio, median frequency, total integral, integral < 300 Hz, and peak frequency with joint spaces in the JVA measurements. Conclusions: JT and JVA may serve as rapid, non-invasive, and radiation-free dynamic diagnostic tools for monitoring and screening TMJ abnormalities before and during orthodontic treatment.

• Journal of Oral Medicine and Pain
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• v.38 no.1
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• pp.69-76
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• 2013

Aim : The purpose of this study was to investigate the hypothesis that treatment with self-checking behavior management program was valuable in the management of temporomandibular disorders compared with a existing method treatment group. Methods : All participants who are diagnosed with temporomandibular disorders were treated with medication and physical therapy. They came into the clinic at intervals of two weeks, three times. The signs and symptoms were assessed investigating Pain NRS(Numerical Rating Scale), MCO(Maximum comfortable opening), Noise NRS, LOM(Limitation of Mouth opening) NRS at every visit. Experimental group received instructions repeatedly by using self evaluation questionnaire. Control group was educated once at the beginning of treatment. The difference Pain NRS, MCO, Noise NRS, LOM NRS between first and second visits, first and third visits were estimated.. Result :Experimental group showed greater improvement on MCO difference after stopping medication(p=0.001). This improvements were prominent in the male(p=0.001) and the first or second decade of the patients(p=0.004). Conclusion : The present study showed that there was better result when educating repeatedly with using self evaluation questionnaire than educating once at the beginning of the treatment.

• The korean journal of orthodontics
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• v.20 no.3 s.32
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• pp.541-552
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• 1990

Until now it has not surely been pointed out about the relation between the biting force and the facial types in scientific view. But it's correlation was assumed by several scientists : recently some literatures reported about the maximum biting force and facial types, but there's only a little articles about the relation between the biting force(biting force contain maximum biting force, chewing force and swallowing force) and facial type. So this study was, firstly, performed to establish the relation of the nomal face and long face versus biting force. 2ndly it was performed to establish the relation between the difference in mouth opening degrees versus biting force. 3rdly it was performed to establish the relation between male and female versus biting force. Biting force was measured from 56 adults (normal 26, long 30) whose samples was selected from Yonsei university students and Hospital patients. Sample was divided into 2groups (normal and long) by lateral cephalogram. The results of this study was obtained as follows. 1. Maximum biting force and chewing force in long face was smaller than normal face. 2. When the thickness of transducer was changed from 6m to 9mm, maximum biting force andchewingforcewaslargerthanbefore. 3. In case of comparing with male and female, male was larger than female in maximum biting force and chewing force.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.388-395
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• 2011

This study was performed to grasp the relation between the effect and the satisfaction of a mouth gymnastics program on the promotion of oral function of old persons. The experimental group of 47 old persons conducted a mouth gymnastics exercise two times every week for 12 weeks, while the control group of 39 old persons carrying out physical examinations. The mean salivary secretion in the experimental group was 0.075 ml and more than 0.046 ml in the control group. Maximum mouth opening in the experimental group, 4.12 cm, was higher than 3.92 cm in the control. Oral diadochokinesis in experimental and control group was 1.69 times per second and 1.65, respectively. The result of principal component analysis by Quartimax method with Kaiser normalization showed that program prevalence prediction of mouth-gymnastics exercise was high, and it is estimated that this exercise program would be more popular for health promotion of old persons. From the correlation analysis, mouth gymnastics exercise made salivary flow increase(r=.592), this exercise should be recommended actively for improving mouth health of old persons. Also more modification is required for old persons with difficulty in mouth gymnastics exercise. Some movements of the mouth gymnastics exercise need be modified, and then the exercise should be publicized as one of the ways to improve holistic health of the aged.

• Journal of Oral Medicine and Pain
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• v.40 no.2
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• pp.72-78
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• 2015

Purpose: The purpose of this research was twofold: to compare the short-term efficacy of once-off education versus repetitive education (RE) of patients suffering from temporomandibular disorders (TMDs) and to determine whether there was any correlation amongst patient demographics, recommendation adherence degree and pain levels. Methods: A total of 848 patients with TMDs were enrolled. The control group consisted of patients who received a standard conservative treatment (STD) over at least 6 visits with education provided only during the first visit. The experimental group consisted of patients who received STD but had also been given RE (STD+RE). The RE was delivered through a standardized self-assessment questionnaire (SAQ) that was completed by the patient during each visit. Pain, which included maximum comfortable opening (MCO) of the mouth and limitation of mouth opening (LOM), was compared between the two groups. Behavior pattern and reported pain level changes in the group who used the SAQ were also analyzed. Results: The LOM was significantly improved in all of the experimental group patients (especially in females under 30 years of age, p<0.05). The MCO was significantly higher in females (p=0.029). All of the patients displayed improvements in their habits following RE, which resulted in a strong correlation with pain reduction. Adhering to the recommendations regarding questions 14 and 15 of the SAQ appeared to have the greatest effect on pain reduction. Conclusions: These results clearly demonstrate that RE is more effective than once-off education for TMD patients who are female or under 30 years of age.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.6
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• pp.532-535
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• 2005

The objective of this study is assessment of the efficacy of upper joint space arthrocentesis on prevention of TMJ injury from patient with mantibular fractures. We divided the patients into two groups, one which consist of 24 patients who are taken arthrocentesis while open reduction of mandibular fracture, the other which consist of 27 patients without arthrocentesis from Jan 1999 to Dec 2001. We measured maximum mouth opening, excursive movement range respectively one week, one month, three months later after operation. The patients were instructed to mark on 10 cm VAS for evaluation of TMJ pain during resting, mouth opening, and mastication. We evaluated the signs and symptoms of temporomandibular disorder clinically and radiographically 6 months later. The result of this study is that there is a reduction of pain and increase of range of mandibular motion in both groups but in patients with arthrocentesis there is relatively reduction of pain and increase of range of mandibular motion compared with control group. On the points of 6 months later, temporomandibular disorder occurred in 4 patients (16.7%) in group with arthrocentesis and 13 patients (47.1%) in control group. In conclusion, we think that supplemental therapy such as arthrocentesis is helpful for the recovery of jaw function and prevention of the development of temporomandibular disorder after facial trauma.

• Journal of Oral Medicine and Pain
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• v.23 no.1
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• pp.65-73
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• 1998

This study evaluated whether substantial airflow resistance changes occurred by changing jaw position in normal and snoring subjects. A case-control design was utilized to assess group differences. Subjects included 11 snoring patients and 10 non-snoring subjects. Airway resistance was assessed using a whole body plethysmograph. Subjects in this study had their mouth opening standardized to a position of 7 mm of vertical separation and the resistance was measured under the following conditions; normal jaw position and 2/3 maximum protrusive jaw position. The results were as follows : 1. The airway resistance was higher in snoring group than in non-snoring group. 2. Both groups had a significant decrease in their airflow resistance upon jaw protrusion. In conclusion, these data document that airflow resistance can be significantly influenced by jaw positioning. Moving the jaw in a protrusive position produced reduction of resistance.

• Journal of Oral Medicine and Pain
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• v.47 no.4
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• pp.198-205
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• 2022

Purpose: The first-line treatment of temporomandibular joint disorders (TMDs) should include self-management and education. Self-management techniques include moist heat application, stretching, diet control, and mandibular rest position adjustment. Although the effectiveness of video educational resources has been studied in multiple sectors, their application in TMD management has not yet been explored. This study seeks to assess how effective media education was at motivating TMD patients to self-management and improve symptoms. Methods: Data were obtained from the hospital records of TMD patients who visited the Department of Oral Medicine, Yonsei University Dental Hospital, between May 2020 and December 2021. First, without any differences between groups, a significance analysis was conducted between the degree of self-management and symptom improvement over time. At the second visit, one group received media education (n=31) linked to TMD management, while the other received written-oriented education (n=45). At the third visit, the number of precautions taken by the patients was determined and contrasted to that recorded in the previous visit between the groups. Generalized estimated equation multivariate models were applied for statistical analysis. Results: In the media education group, the frequency of stretching and the number of patients on pain-free diets increased substantially. Taking precautions improved daily pain intensity, maximum mouth opening, and pain intensity during the maximum unassisted opening. Conclusions: Media education could be beneficial for TMD patients because it allows them to take self-management precautions. The symptoms of the media education group improved, with no considerable distinction between both groups.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.29-44
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• 1995

A model experiment on the pair midwater trawl net applicable to 800 PS class Korean pair bottom trawlers was carried out in the special-prepared experimental thank. the tank was prepared as a reverse trapezoid shape in its vertical section by digging out flat soil. The dimension of the tank showed the 9.6 W$\times$43.0 L(m) of the upper fringe and the 4.8 W$\times$38.0 L(m) of the bottom with 3.0m in depth. The depth of water was maintained 2.7m during experiment. The model net was prepared based on the Tauti's similarity law of fishing gear in 1/30 scale considering the dimension of the experimental tank. Mouth performance of the model net during towing were determined by the photographs taken in front of the net mouth with the combinations of towing velocity, warp length and distance between paired boats. The results obtained can be summarized as follows: 1. Vertical opening of the model nets A and B was varied in the range of 0.18~0.88 m and 0.21~0.78 m (which can be converted into 5.4~26.4m and 6.3~23.4 m in the full-scale net) respectively, and was varied predominantly by towing speed. Vertical opening (H which is appendixed m for the model net. f for the full-scale net. A and B for the types of the model net) can be expressed as the function of towing velocity$V_t$as in the model net $V_t$ : m/ sec)$H_{mA}$=1.67$e^{-1.65V_t}$ $H_{mB}$=1.15$e^{-1.13V_t}$, in the full-scale net ($V_t$ : k't) $H_{fA}$=50.27$e^-0.37V_t$ $H_{fB}$=34.46$e^{-0.26Vt}$. 2. Horizontal opening of the model nets An and b was varied in the range of 1.03~1.54m and 1.04~1.55 m (which can be converted into 30.9~46.2 m and 31.2~46.5m in the full-scale net) respectively, and was varied predominantly by distance between paired boats. Horizontal opening (W, appendixes are as same as the former) an be expressed as the function of distance between paired boats $D_b$as in the model net $W_{mA}$=0.69+0.09$D_b$ $W{mB}$=0.73+0.09$D_b$, in the full-scale net $W_{fA}$=20.81+0.09$D_b$ $W_{fB}$=22.11+0.09$D_b$ 3. Net opening area of the model net A and B was varied in the range of 0.28~1.04 $m^2$ and 0.33~0.94$m^2$(which can be converted into 252~936$m^2$ and 297~846$m^2$ in the full-scale net) respectively, and was varied predominantly by towing velocity. Net opening area ($S$, appendixes are as same as the former) van be expressed as the function of towing velocity$V_t$ as in the model net $v_t$ : m/sec) $S_{Ma}$=2.01$e^{-1.54V_T}$ $S_{mA}$=1.40$e^{-1.65V_t}$, in the full-scale net ($V_t$ : k't) $S_{fA}$=1.807$e^-0.35V_t$ $S_{fA}$=1.265$e^{-0.24V_t}$. 4. Filtering volume of the model nets A and B was varied in the range of 0.32~0.55 $m^3$ and 0.37~0.55$m^3$(which can be converted into 8.640~14.850 $m^3$ and 9.990~14.850$m3$in the full~scale net) respectively, and was predominantly varied by towing speed. filtering volume of the model net-A showed the maximum at the towing speed 0.69 m/sec(3 k't in the full-scale net), compared with that of the model net B showed at 0.92 m/sec(4 k't in the full-scale net).

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.93-98
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• 2012

In order to capture the fast crack propagation in an unmanipulated concrete fracture test, we employed mechanoluminascent(ML) material, which emits visible light when stressed, as a crack visualization tool. Three-point bending fracture test setup, a paint type ML material and a high speed camera were used to capture the images of fast moving cracks. The maximum size of coarse aggregates of concrete was used as an experimental parameter. The crack images, loading, and crack mouth opening displacement were successfully recorded as a function of time elapsed. From the test results, several interesting cracking behavior in the unmanipulated fracture test was observed in such that (1) the crack moves fast while the load is slowly decreased after the maximum loading, and (2) the crack in concrete with larger coarse aggregates moves faster than the others.