• The Journal of Advanced Prosthodontics
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• 제12권6호
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• pp.329-337
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• 2020

PURPOSE. To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implant-supported prostheses manufactured with cobalt-chromium (Co-Cr) and zirconia (Zr), and whether ceramic application, spark erosion, and simulation of masticatory cycles modify biomechanical parameters (marginal fit, screw-loosening torque, and strain) on the implant-supported system. MATERIALS AND METHODS. Ten full-arch fixed frameworks were manufactured by a CAD/CAM milling system with Co-Cr and Zr (n=5/group). The marginal fit between the abutment and frameworks was measured as stated by single-screw test. Screw-loosening torque evaluated screw stability, and strain analysis was explored on the implant-supported system. All analyses were performed at 3 distinct times: after framework manufacturing; after ceramic application in both materials' frameworks; and after the spark erosion in Co-Cr frameworks. Afterward, stability analysis was re-evaluated after 106 mechanical cycles (2 Hz/150-N) for both materials. Statistical analyses were performed by Kruskal-Wallis and Dunn tests (α=.05). RESULTS. No difference between the two materials was found for marginal fit, screwloosening torque, and strain after framework manufacturing (P>.05). Ceramic application did not affect the variables (P>.05). Spark erosion optimized marginal fit and strain medians for Co-Cr frameworks (P<.05). Screw-loosening torque was significantly reduced by masticatory simulation (P<.05) regardless of the framework materials. CONCLUSION. Co-Cr and Zr frameworks presented similar biomechanical behavior. Ceramic application had no effect on the biomechanical behavior of either material. Spark erosion was an effective technique to improve Co-Cr biomechanical behavior on the implant-supported system. Screw-loosening torque was reduced for both materials after masticatory simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2439-2441
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• 1998

In this research, the sensor and control system for self detecting masticatory muscle relaxation appliances. A strain gauge is used to measure a strength of tooth clenching force. A bridge circuit and voltage amplifier is designed to amplify measured signals and RF transmitter and receiver is also designed to communicate inner and outer mouth device. The experiments are performed to show the effectiveness of designed system.

• Journal of Oral Medicine and Pain
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• 제7권1호
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• pp.32-40
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• 1982

Functional disorders of the temporomamdibular joint and masticatory system were investigated in 209 men and 110 women, ranging form 20 to 30 years old, with a method devised by Agerberg and Carlsson. The investigated persons were dental students of the School of Dentistry, Seoul National University and student nurses of the School of Medicine, Seoul National University. The obtained results were as follows : 1. Facial pain and headache were reported by 32%. 2. Pain on gaping was localized mainly to the temporomandibular area and was noted in 8%. 3. Chicking of the temporomandibular joints was reported by 26%, somewhat more often by males. 4. Clenching of the teeth was relatively common in men and biting of the lip was comman in women. 5. Prevalence of mandibular dysfunction was found in 53%.

• Journal of Oral Medicine and Pain
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• 제32권4호
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• pp.421-429
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• 2007

최근 tactile sensor 를 사용하여 근육의 경도와 탄성도를 조사하는 방법이 저작근의 새로운 평가방법으로 제시되고 있다. 본 연구의 목적은 촉각센서를 이용하여 일정시간 껌씹기를 시행전, 중, 후의 저작근의 경도와 탄성도를 조사하여 향후 턱관절 장애 환자의 저작근 평가를 위한 기초자료를 확보하는 데 있다. 건강한 성인 8명을 대상으로 양측 전측두근(anterior temporalis), 하교근(inferior masseter)의 경도와 탄성도를 촉각센서 (Venustron II, Axion Co., Japan)를 이용하여 다음과 같이 측정하였다. 피검자들을 unit-chair에 바로 앉힌 상태에서 양측 교근 및 측두근 부위를 촉진을 통해 전 측두근(temporalis anterior), 하 교근(masseter inferior) 두 부위를 펜으로 표시하였다. 실험의 재현성을 위하여 투명한 종이에 ala-tragus line을 표시한 후 두 부위를 투명종이 위에 표시하였다. 편안한 상태에서 촉각센서를 사용하여 양측 하 교근 및 전 측두근의 경도와 탄성도를 측정한 후, 껌(Excellent Breath, Taiyo Co., Japan)을 양측으로 씹게 하여 1초당 2회의 속도로 씹게 하였다. 껌을 40분동안 저작하는 동안 10분, 20분, 30분, 40분에 양측 하 교근 및 전 측두근의 경도와 탄성도를 측정하였다. 그 후 껌을 뱉게 하고 하악의 안정위 상태에서 10분, 20분, 30분, 40분 후 양측하 교근 및 전 측두근의 경도와 탄성도를 각각 측정하였다. 측정치들을 반복측정 이원분산분석과 다중비교를 통하여 비교하였다. 실험결과 측두근과 교근을 비교 시 탄성도, 경도 모두 교근의 변화가 유의하게 크다. 또한 저작하면 서서히 경도는 증가하며 탄성도는 반대로 감소한다. 탄성도 및 경도는 저작 시 신속히 증가하나 저작 종료 후에는 탄성도만 신속히 회복되나 경도는 약 10분 이상의 일정시간이 지나야 회복된다. 이상의 결과들을 보아 임상적으로 좀 더 다양한 연구와 기초자료가 확보된다면, 저작근의 근육 상태를 평가하는데, 근육의 탄성도와 경도를 조사하는 tactile sensor system은 유익한 기기로서 활용될 수 있을 것이다.

• Journal of Oral Medicine and Pain
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• 제15권1호
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• pp.105-115
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• 1991

The purpose of the study was to evaluate the occlusal stability at the moment of dynamic occlusal tooth contact and to investigate the correlation between the occlusal stability and the masticatory muscle activities. It also evaluated the effect of short-term use of occlusal splints on the occlusal stability and the masticatory muscle activities in patients with temporomandibular disorders during maximum voluntary clenching by synchondronized with temporomandibular disorders during maximum voluntary clenching by synchronized use of the T-Scan system(Tekscan, Inc, USA) and K6-Diagnostic system(Myo-tronics Research, Inc, USA) The author measured its distance from retruded contact position(RCP) to intercuspal position(IP), average of contact intervals(ACI), total left-right statistics(TLR), average muscle activities of masseter and anterior temporal muscles during maximum voluntary clenching in 20 patients with temporomandibular disorders and 22 dental students as a control group. The data were compared between two groups and investigated for any correlations between the parameters. The results were as follows : 1. Both of the mean average of contact intervals and the mean absolute value of total left-right statistics during maximum voluntary clenching were increased in the patient group when compared with the control group. 2. Muscular disharmony of anterior temporal muscles of patient group is significantly greater than that of control group. However, muscular disharmony of masseter muscles of patient group is not significantly greater than that of control group. 3. There were significant correlations between muscular disharmony of anterior temporal muscles and average of contact intervals as well as total left-right statistics, and also between muscular disharmony of masseter muscles and total left-right statistics. 4. There were not any significant correlations between distance from RCP to IP and any other parameters. 5. There were a significant decrease in total left-right statistics and muscular disharmony of anterior temporal muscles during maximum voluntary clenching after a 1week use of occlusal splint in the patient group.

• 대한치과의사협회지
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• 제54권6호
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• pp.438-446
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• 2016

Severe tooth wear may cause the pathologic change of the TMJ and masticatory muscles, unesthetic facial appearance, pathogenic pulp and occlusal disharmony. Treating patients with severely worn dentition often requires full mouth rehabilitation with increasing vertical dimension. Proper diagnosis and treatment planning are important for esthetic and functional definitive restorations and the long term stability of the neuromuscular system and the TMJ. In this case, 66 year-old female presented with generalized worn dentition. Based on assessment, pathologic destruction of teeth structure on entire dentition was caused by masticatory force and diet habit without loss of vertical dimension. Subsequently, 3 mm increase of vertical dimension that based on incisor for tooth restoration and esthetic improvement was determined. After 8 weeks stabilization period with temporary fixed prostheses, definitive prostheses were fabricated. After 6 months follow up period, satisfactory outcomes were attained both functional and esthetic aspects through this procedure.

• Journal of Oral Medicine and Pain
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• 제35권1호
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• pp.49-59
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• 2010

본 연구는 단기간의 인공소음과 음악 청취에 대한 저작근의 반응을 조사하였다. 연구의 가설은 높은 소음은 작은 소음이나 음악에 비하여 저작근의 경도는 높이고 탄성도는 감소시킨다는 것이다. 15명의 지원자에게 60 dB 과 100 dB 의 소음과 음악을 각각 6분씩 들려주고 청취 전과, 청취 2분후, 4분후, 6분후에 tactile sensor system을 이용하여 교근과 측두근의 경도 및 탄성도를 조사하였다. 첫째날은 100 dB의 소음, 둘째날은 100 dB 의 음악, 셋째날은 60 dB 의 소음, 넷째날은 60 dB 의 음악을 청취한 후 조사하였다. 실험 결과, 60 dB, 100 dB 모두에서 소음과 음악 청취군 간에는 유의성 있는 차이가 대부분 없었으며, 60 dB, 100 dB군간의 비교에서 측두근에서는 유의한 차이가 없었으나 교근의 경우, 음악군에서는 탄성도에서, 소음군에서는 경도에서 유의한 차이를 보여주었다. 이는 소음의 종류에 관계없이 비록 음악이고 단기간의 청취일지라도 큰 소음인 경우에는 저작근의 수축을 야기할 수 있음을 의미한다.

• 대한치과보철학회지
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• 제36권4호
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• pp.598-614
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• 1998

This study was performed to investigate the influence of lateral guidance pattern and chewing pattern on masticatory muscle activity and occlusal contact pattern. Twenty-five patients with temporomandibular disorders and thirty students without temporomandibular disorders were selected for this study. Electromyographic examination and occlusal contact examination were performed simultaneously with Bio-Pak System (Bioresearch Inc.,U.S.A.) and T-Scan System(Tekscan Co., USA). The obtained results were as follows : 1. The EMG activity of masseter and anterior temporal muscle in patient group with canine guidance was higher than with non-canine guidance. but there was no significant difference (p>0.05). 2. The EMG activity of anterior temporal muscle in normal group with non-canine guidance was higher at preferred chewing side than at opposite side (p<0.05). 3. The EMG activity of masseter muscle was higher in normal group than in patient group (p<0.05). 4. The number of occlusal contact in patient group with canine guidance was higher than with non-canine guidance, but there was no significant difference (p>0.05). 5. The occlusal contact force at preferred chewing side was higher in patient group than in normal group(p<0.05).

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권5호
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• pp.488-492
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• 2010

This review evaluates the literature on the relationship between mandibular condylar process fracture and temporomadibular joint (TMJ). The topic of condylar fracture generated more discussion and controversy than any other field of maxillofacial trauma associated with TMJ. Disturbance of occlusal function, devia-tion of mandible, internal derangements of TMJ, and ankylosis of the joint with resultant inability to move the jaw are sequelae of condylar process fracture. Thus it is necessary to understand how the masticatory system adapts to the structural alterations that accompany fractures of the mandibular condyle. Treatment of condylar process fracture include two methods ; closed treatment and open treatment. If one chooses totreat closed, one must understand that adaptations in the musculature, skeleton, and dentition will be necessary. Open treatment of condylar process fractures probably requires fewer adaptations within the masticatory system to provide a favorable functional outcome. However, one must weigh the risk of open surgery against the possible improvement in outcome. The risks are not just surgical risk, but biological risk as well, such as disruption of the blood supply to the condyle. This review presents relevant aspects of change of TMJ associated with condylar process fracture.

• Journal of Oral Medicine and Pain
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• 제45권3호
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• pp.49-55
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• 2020

Purpose: This study investigated the association between the objective indicator of masticatory function assessment and the masseter muscle thickness (MMT) using ultrasound imaging. Methods: A total of 99 subjects (males: 24, females: 75, mean age: 76) were analyzed. The maximum bite force (MBF) was measured with a pressure-sensitive sheet and an image scanner. The mixing ability index (MAI) was calculated by image analysis after asking the subjects to chew a wax specimen. The MMT during rest and clenching were obtained with a diagnostic ultrasound system, and the difference in MMT during rest and MMT during clenching was defined as the difference in masseter muscle thickness (DMMT). Multiple regression analysis was performed to determine the independent variables affecting MBF and MAI. Results: The MBF showed correlation with the number of remaining teeth (β=0.346, p=0.002) and DMMT (β=0.251, p=0.011). The MAI correlated with only the number of remaining teeth (β=0.476, p<0.001). Conclusions: The DMMT reflects the state of masseter muscle contraction, and can be used as a predictor as well as the number of teeth when assessing masticatory function.