• 대한치과보철학회지
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• 제45권1호
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• pp.119-130
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• 2007

Statement of problem: A few dry lubricants were applied to abutment screws for the improvement of joint stability. Purpose: The purpose of this study was to evaluate the surface change and fit of TiN-Coated abutment screw through the examination of tested screws in the field emission scanning electron microscope(FE-SEM;Netherland, Phillips co., model:XL 30 SFEG) after repeated closing and opening. Materials and method: Titanium(3i/implant Innovations Inc, USA) and Gold-Tite abutment screws(3i/implant Innovations Inc, USA) were selected for Group A and C respectively. TiN coated titanium abutment screws were also divided into two groups, Group B and D. Abutment screws of each group and the fit of abutment screw/implant fixture/abutment were observed on FE-SEM after repeated closing and opening test respectively. Results: 1. The abutment screws of TiN coated groups(Group B and D) showed more remarkable wear resistance in the threads of the screw than those of the other group(Group A and C). 2. There were more severe wear and defect of TiN coating in Group D tightened to 32 Ncm than Group B to 20 Ncm. 3. There was no difference in the fit of abutment screw/fixture/abutment among four groups, Group A, Group B, Group C and Group D. Conclusion: Under the conditions of this study, it is suggested that TiN coating of abutment screw be clinically acceptable and be expected to reduce the risk of abutment screw loosening. TiN coating of abutment screw showed good resistance against wear and the adequate fit of abutment screw/implant fixture/abutment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권5호
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• pp.305-309
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• 2012

Temporomandibular joint (TMJ) subluxation and dislocation are uncommon but very unpleasant and distressing conditions to patients. Subluxation of the TMJ is an excessively abnormal condylar excursion secondary to flaccidity and laxity of the capsule. When the condyle head excurses anterior to the eminence upon wide opening, it can return to the fossa by self-manipulation or non-surgical conservative reduction. Surgery is recommended if a complete dislocation, so-called open lock, occurs as a chronic or recurrent protracted condition that cannot be reduced voluntarily. A range of surgical procedures can be performed to limit condylar hypermobility inclusing soft tissue tethering, creation of articular obstacles, removal of mechanical blockade and augmentation of articular eminence using different kinds of grafts. In the present case, a 74-year-old woman was diagnosed with a chronic TMJ dislocation that had lasted for 6 months. Bilateral condylectomy was performed and the post-operative results were good without functional limitations or recurrence.

• ETRI Journal
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• 제37권5호
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• pp.906-916
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• 2015

High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from $60mV_{p-p}$ to $180mV_{p-p}$ adaptively, where the transmit non-return-to-zero signal amplitude is a constant $500mV_{p-p}$.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제16권2호
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• pp.215-220
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• 1994

In the case of the trauma on the maxillofacial region occurred, we think that one of the most important thing is recovery of the function as well as reconstruction of the anatomical form. Especially, it has been that the structure of the surrounded temporomandibular joint has a great possibility to cause mouth opening limitation when a bit of displacement is caused. Therefore, in the case of the trauma on mid-face we think that we treat it after complete evaluate condition of soft and hard tissue surrounding the articular disc as well as fracture site. We report results of our study, since we obtained good results from our study concerning the refixation of the zygomatic arch, high condylectomy, coronoidectomy and myotomy for the patient being suffered from the arthrosis of the temporomandibular joint caused by insufficient fracture treatment of zygomatic arch and coronoid process.

• Journal of Oral Medicine and Pain
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• 제49권2호
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• pp.35-39
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• 2024

Osteomyelitis of the jaw is an inflammatory process of the bone marrow that is caused by odontogenic local infection and trauma such as tooth extraction and fractures in the oral and maxillofacial region. The clinical signs include pain, swelling, pus formation, and limited mouth opening. Chronic osteomyelitis presents a diagnostic challenge because of the variability of symptoms across different disease stages and varying health conditions of the patients. This report presents a case of osteomyelitis that was misdiagnosed as a temporomandibular joint disorder (TMD) after tooth extraction. The patient was treated for inflammation after tooth extraction in the early stage; however, as the osteomyelitis progressed chronically, symptoms mimicked those of a TMD. The patient was finally diagnosed with osteomyelitis 6 months after tooth extraction. A review of this case and relevant literature revealed the necessity for a differential diagnosis of chronic osteomyelitis that mimics TMD symptoms.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권2호
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• pp.134-137
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• 2017

Giant cell tumor (GCT) of the craniofacial bones has been reported but they are not common. This tumor occurs more often in women than in men and predominantly affects patients around the third to fifth decade of life. GCTs are generally benign but can be locally aggressive as well. We report a case of GCT involving the temporomandibular joint (TMJ), which was initially thought to be temporomandibular disorder (TMD). A 22-year-old female presented with swelling and pain over the right temporal region for 18 months associated with jaw locking and clicking sounds. On examination, her jaw deviated to the right during opening and there was a $2{\times}2$ cm swelling over the right temporal region. Despite routine treatment for TMD, the swelling increased in size. Computed tomography and magnetic resonance imaging of the brain and TMJ revealed an erosive tumor of the temporal bone involving the TMJ which was displacing the temporal lobe. Surgical excision was done and the tumor removed completely. Histopathological examination was consistent with a GCT. No clinical or radiological recurrence was detected 10 months post-surgery.

• Computers and Concrete
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• 제34권1호
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• pp.15-31
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• 2024

This study explores the failure mechanisms of 'I' shaped non-persistent cracks under uniaxial loads through a combination of experimental tests and numerical simulations. Concrete specimens measuring 200 mm×200 mm×50 mm were manufactured, featuring 'I' shaped non-persistent joints. The number of these joints varied from one to three, with angles set at 0, 30, 60, and 90 degrees. Twelve configurations, differing in the placement of pre-existing joints, were considered, where larger joints measured 80 mm in length and smaller cracks persisted for 20 mm with a 1 mm crack opening. Numerical models were developed for the 12 specimens, and loading in Y-axis direction was 0.05 mm/min, considering a concrete tensile strength of 5 MPa. Results reveal that crack starting was primarily influenced by the slope of joint that lacks persistence in relation to the loading direction and the number of joints. The compressive strength of the samples exhibited variations based on joint layout and failure mode. The study reveals a correlation between the failure behavior of joints and the number of induced tensile fracture, which increased with higher joint angles. Specimen strength increased with decreasing joint angles and numbers. The strength and failure processes exhibited similarities in both laboratory testing and numerical modeling methods.

• 대한소아치과학회지
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• 제42권3호
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• pp.242-248
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• 2015

최대개구량은 측두하악관절과 저작계의 임상 기능 평가에 유용한 진단 도구이다. 이 연구는 한국 유치열기 어린이의 정상 최대개구량을 측정하고 관련 인자들 간의 상관관계를 조사함으로써, 소아 악관절 장애의 진단 및 치과치료시 안전한 개구 범위 정립에 기여할 수 있는 기초 자료를 마련하고자 하였다. 악관절장애가 없는 건강한 어린이(만2-6세) 151명을 대상으로 최대개구량을 측정하고, 성별, 연령, 신장, 체중과 입의 너비를 기록하였다. 평균 최대개구량은 $37.72{\pm}5.10mm$였고 성별에 따른 유의한 차이는 없었으나, 연령, 신장, 체중, 입의 너비 증가에 따라서는 유의하게 증가하였다(p < 0.05). 최대개구량과 관련 요인들 간의 상관관계 분석 결과, 신장에서 가장 높은 상관관계가 관찰되었다. 결론적으로 한국 유치열기 어린이의 정상 최대개구량에 관한 자료를 얻을 수 있었고, 이 연구는 소아 악관절장애의 진단 및 안전 개구 범위에 관한 기초 지식을 제공할 수 있을 것이다.

• Journal of Oral Medicine and Pain
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• 제18권2호
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• pp.29-41
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• 1993

A prevalence study was carried out on 847 CMD patients who had visited the Department of Oral Medicine in Pusan National University from 1990 to 1993. To obtain the same type of information, all subjects were interviewed and examined clinically using a standardized examination form, The ratio of women to men was about 3:1 and all subjects were divided into acute and chronic groups on the basis of 6 months of duration. Diagnostic groups consisted of muscle disorder, joint disorder and muscle-joint disorder. As related to gender, duration and diagnosis subjective and objective symptoms in CMD were studied. The obtained results were as follows : 1. Muscle-joint disorder had the highest percent, followed by muscle disorder and joint disorder. 2. The most common reasons for CMD treatment were pain, joint noise and limited opening, while headache and neckache were relatively often reported as associated symptoms and dizziness, ringing in the ears also reported as secondary CNS excitatory effects. 3. Pain was more ofter seen in women, acute group and muscle-related disorder groups (p<0.05, p<0.01). Noise was significantly frequent in chronic group and joint-related groups (p<0.01). 4. Analysis of contributing factors presented that macrotrauma was found frequently in men (p<0.05), and that muscle-related groups were more related to stress than joint disorder grop (p<0.05). 5. Hard end feel was seen significantly often in joint-related disorder group (p<0.05). On the other hand, soft end feel was frequent in muscle disorder. 6. Reciprocal clicks and crepitation increased with chronicity. Subjects with joint-related disorder groups significantly often reported all kinds of noises (p<0.01). 7. Tender muscles and joints were more often reported in women and chronic group. Whereas muscle-related disorder groups revealed significantly more tender muscles (p<0.01). joint-related disorder groups presented significantly more tender joints (p<0.01).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권4호
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• pp.367-374
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• 2007

Purpose: The diagnostic relevancies and characteristics and of clinical methods in the diagnosis of internal derangement(ID) were tested by comparing the results of them with those of magnetic resonance imaging(MRI). Methods: 75 patients(150 temporomandibular joints; TMJs), who were suspected to have ID by clinical diagnoses, were included. Clinical diagnoses including mouth opening pathway and TMJ sound were conducted and MRI takings were done. Accuracies, sensitivities, specificities, positive predictive values, and negative predictive values of clinical diagnosis, mouth opening pathway, and TMJ sound were calculated by comparing with diagnoses with MRIs. Results: Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of clinical diagnosis were 59.3%, 83%, 49%, 81%, and 51%. They were 59%, 82%, 25%, 73%, and 35% for mouth opening pathways. Although deviation was somewhat accurate for representing disc displacement with reduction(ADDWR), other discrepancies on opening pathways were not clinically relevant. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of clicking sounds were 85%, 49%, 78%, 85%, and 37%. TMJs with crepitus were only three. But all TMJs with crepitus were diagnosed to have disc displacement without reduction(ADDWOR). Conclusion: When compared with diagnoses with MRIs, clinical diagnoses for ID were not so accurate. But they were suitable for screening tests for ID. Opening pathways and TMJ sounds were not so relevant in the diagnoses of IDs and so it was concluded that considerations for other factors must be included in the diagnoses of IDs.