• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.5
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• pp.259-266
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• 2022

The relationship between obstructive sleep apnea (OSA) and diverse types of pain conditions have been proposed. However, no consensus on the relationship between OSA and painful temporomandibular disorders (TMDs) has been established. Therefore, this systematic review has been conducted to review the existing literatures and provide comprehensive synthesis of such literatures about OSA and painful TMDs using the evidence-based methodology. A literature search was conducted using two electronic databases, Scopus, and PubMed. Risk of bias was assessed using the risk-of-bias assessment tool for non-randomized study version 2.0. A total of 158 articles were screened from the initial search and eventually, 5 articles were included in this systematic review. One study adopted both the longitudinal prospective cohort and case-control designs and other 4 articles adopted the cross-sectional design. Two studies employed polysomnography (PSG) for the diagnosis of OSA and mentioned the results from the PSG. All cross-sectional studies demonstrated higher OSA prevalence among patients with TMD, and one cohort study suggested OSA as a risk factor for TMD. OSA appears to have potential influences on the development of TMD; however, the role of TMD in the development of OSA remains to be unknown owing to the lack of high-quality evidences.

• Structural Engineering and Mechanics
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• v.81 no.4
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• pp.429-441
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• 2022

A probabilistic assessment of the seismic-excited buildings with a multiple-tuned-mass-damper (MTMD) system is carried out in the presence of uncertainties of the structural model, MTMD system, and the stochastic model of the seismic excitations. A free search optimization procedure of the individual mass, stiffness and, damping parameters of the MTMD system based on the snap-drift cuckoo search (SDCS) optimization algorithm is proposed for the optimal design of the MTMD system. Considering a 10-story structure in three cases equipped with single tuned mass damper (STMS), 5-TMD and 10-TMD, sensitivity analyses are carried out using Sobol' indices based on the Monte Carlo simulation (MCS) method. Considering different seismic performance levels, the reliability analyses are done using MCS and kriging-based MCS methods. The results show the maximum structural responses are more affected by changes in the PGA and the stiffness coefficients of the structural floors and TMDs. The results indicate the kriging-based MCS method can estimate the accurate amount of failure probability by spending less time than the MCS. The results also show the MTMD gives a significant reduction in the structural failure probability. The effect of the MTMD on the reduction of the failure probability is remarkable in the performance levels of life safety and collapse prevention. The maximum drift of floors may be reduced for the nominal structural system by increasing the TMDs, however, the complexity of the MTMD model and increasing its corresponding uncertainty sources can be caused a slight increase in the failure probability of the structure.

• Journal of Oral Medicine and Pain
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• v.48 no.3
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• pp.112-117
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• 2023

Coronoid process hyperplasia (CPH) of the mandible is a rare condition in which abnormal elongation of the coronoid process leads to chronic mandibular hypomobility. CPH causes impingement or impedance of the coronoid process on the inner surface of the frontal part of the zygomatic bone during mouth opening. The lack of significant symptoms makes the diagnosis difficult. Its etiology remains inconclusive despite several theories being suggested. In this report, three reviewed cases are presented. All three patients visited our clinic with limited mouth opening as the chief complaint. Standard clinical and radiographic examinations were conducted under the initial impression of temporomandibular disorders (TMDs), and restricted jaw movements were confirmed in all cases. The absence of improved signs and symptoms following conservative treatment for TMDs or the indeterminate plain radiographs required the attending clinicians to consider three-dimensional imagery. Computed tomography revealed bilateral coronoid hyperplasia in all cases and impingement on the zygomatic bone in two of the three cases. After concluding that this condition caused the patients' limited mouth opening, the patients were referred to the Department of Oral and Maxillofacial Surgery for possible bilateral coronoidectomy or coronoidotomy. CPH usually presents no symptoms apart from a progressive reduction of mouth opening over time. Diagnosis is often delayed, and patients may undergo unnecessary treatment procedures. Clinicians should be aware of this condition and exercise caution in the differential diagnosis of patients with chronic mandibular hypomobility.

• Smart Structures and Systems
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• v.20 no.1
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• pp.61-74
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• 2017

One of the most reliable and simplest tools for structural vibration control in civil engineering is Tuned Mass Damper, TMD. Provided that the frequency and damping parameters of these dampers are tuned appropriately, they can reduce the vibrations of the structure through their generated inertia forces, as they vibrate continuously. To achieve the optimal parameters of TMD, many different methods have been provided so far. In old approaches, some formulas have been offered based on simplifying models and their applied loadings while novel procedures need to model structures completely in order to obtain TMD parameters. In this paper, with regard to the nonlinear decision-making of fuzzy systems and their enough ability to cope with different unreliability, a method is proposed. Furthermore, by taking advantage of both old and new methods a fuzzy system is designed to be operational and reduce uncertainties related to models and applied loads. To design fuzzy system, it is required to gain data on structures and optimum parameters of TMDs corresponding to these structures. This information is obtained through modeling MDOF systems with various numbers of stories subjected to far and near field earthquakes. The design of the fuzzy systems is performed by three methods: look-up table, the data space grid-partitioning, and clustering. After that, rule weights of Mamdani fuzzy system using the look-up table are optimized through genetic algorithm and rule weights of Sugeno fuzzy system designed based on grid-partitioning methods and clustering data are optimized through ANFIS (Adaptive Neuro-Fuzzy Inference System). By comparing these methods, it is observed that the fuzzy system technique based on data clustering has an efficient function to predict the optimal parameters of TMDs. In this method, average of errors in estimating frequency and damping ratio is close to zero. Also, standard deviation of frequency errors and damping ratio errors decrease by 78% and 4.1% respectively in comparison with the look-up table method. While, this reductions compared to the grid partitioning method are 2.2% and 1.8% respectively. In this research, TMD parameters are estimated for a 15-degree of freedom structure based on designed fuzzy system and are compared to parameters obtained from the genetic algorithm and empirical relations. The progress up to 1.9% and 2% under far-field earthquakes and 0.4% and 2.2% under near-field earthquakes is obtained in decreasing respectively roof maximum displacement and its RMS ratio through fuzzy system method compared to those obtained by empirical relations.

• Journal of Oral Medicine and Pain
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• v.24 no.4
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• pp.439-453
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• 1999

This study was performed to investigate the masicatory efficiency in patients with temporomandibular disorders (TMDs), especially internal derangement of temporomandibular (TM) joint. For this study, 26 patients after treatment and 33 dental students who had no signs and symptoms of TMDs were selected as the patients group and as the normal group, respectively. Mean treatment duration of the patients was. 5.1 months. Verbal rating scale(VRS) and Visual analogue scale(VAS) were used for recording of subjective symptoms. Treatment index (VAS Ti) derived from VAS was calculated for evaluation of treatment progress and clinical examination was also performed for objective symptoms. BioEGN(Bioresearch Inc., Milwaukee, USA) was used for observation chewing movement pattern on peanut, caramel candy, and gum chewing. Chewing time in second and symptoms after chewing were recorded, and pattern of chewing stroke between in affected side and in contralateral side or between in right in left side were compared, and especially, gum chewing pattern between before and after treatment were also compared in the patients group. The data obtained were analysed by SPSS windows program and the results of this study were as follows : 1. Subjective symptoms evaluated by VAS showed no difference between the two groups, but those by VRS showed slight difference for TM joint pain, head not neck symptoms, and chewing ability. 2. There were no difference at the level of subjective symptoms between the subgroups divided by treatment duration of five months in the patients group. However, value of VAS Ti of pain was higher in subgroup of long treatment duration than that of subgroup of short treatment duration. 3. There were no difference in chewing time for peanut or caramel candy between the two groups, but on caramel candy chewing, the patients group complained slight discomfort after swallowing. Chewing velocity and range of motion on gum chewing after treatment in the patients group showed significant difference and greatly improved compared to those to before treatment, and which were not differ from those of normal subjects. In conclusion, treatment of temporomandibular disorders about for five months would greatly improve chewing ability and movement pattern in most of the patients with TMDs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.3
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• pp.125-134
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• 2023

Objectives: The aim of the study was to quantify and compare craniofacial asymmetry in subjects with and without symptoms of temporomandibular joint disorders (TMDs). Materials and Methods: A total of 126 adult subjects were categorized into two groups (63 with a TMDs and 63 without a TMDs), based on detection of symptoms using the Temporomandibular Joint Disorder-Diagnostic Index (TMD-DI) questionnaire. Posteroanterior cephalograms of each subject were traced manually and 17 linear and angular measurements were analyzed. Craniofacial asymmetry was quantified by calculating the asymmetry index (AI) of bilateral parameters for both groups. Results: Intra- and intergroup comparisons were analyzed using independent t-test and Mann-Whitney U test, respectively, with a P<0.05 considered statistically significant. An AI for each linear and angular bilateral parameter was calculated; higher asymmetry was found in TMD-positive patients compared with TMD-negative patients. An intergroup comparison of AIs found highly significant differences for the parameters of antegonial notch to horizontal plane distance, jugular point to horizontal plane distance, antegonial notch to menton distance, antegonial notch to vertical plane distance, condylion to vertical plane distance, and angle formed by vertical plane, O point and antegonial notch. Significant deviation of the menton distance from the facial midline was also evident. Conclusion: Greater facial asymmetry was seen in the TMD-positive group compared with the TMD-negative group. The mandibular region was characterized by asymmetries of greater magnitude compared with the maxilla. Patients with facial asymmetry often require management of temporomandibular joint (TMJ) pathology to achieve a stable, functional, and esthetic result. Ignoring the TMJ during treatment or failing to provide proper management of the TMJ and performing only orthognathic surgery may result in worsening of TMJ-associated symptoms (jaw dysfunction and pain) and re-occurrence of asymmetry and malocclusion. Assessments of facial asymmetry should take into account TMJ disorders to improve diagnostic accuracy and treatment outcomes.

• Journal of Korean Dental Science
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• v.11 no.1
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• pp.21-31
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• 2018

Occlusion may change spontaneously but dental treatment or trauma in the patients with temporomandibular disorders (TMDs) may also alter occlusion. This report presents three cases displaying occlusal changes. Review of literature emphasizes the significance of TMD treatment. Conservative treatment modalities such as counseling, medication, physical therapy and splint therapy may be selected as initial treatment options. Irreversible or invasive treatment, such as orthodontic, prosthodontic, and occlusal adjustment should not be attempted early. In case there is no response to conservative treatment, joint injection, muscle injection, arthrocentesis or arthroscopic surgery might be performed.

• Proceedings of the KAIS Fall Conference
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• 2002.05a
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• pp.215-217
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• 2002

본 논문에서는 CM-MVL(Current Mode Multi-Valued Logic)을 이용한 Host와 LCD Controller 간에 인터페이스 회로를 제안한다. 제안한 회로는 기존의 LVDS(Low Voltage Differential Signaling)과 TMDS(Transition Minimized Differential Signaling)와 같은 전류 특성을 가지며, 3비트 동시 전송이 가능하여 동일한 전송 속도 하에서 보다 많은 데이터를 전송할 수 있다. 그리고 전류에 의한 데이터 전송을 통하여 노이즈에 강한 특성을 나타낸다. 제안한 회로는 HSPICE 시뮬레이션을 통해서 회로의 동작을 확인하였다.

• Journal of Oral Medicine and Pain
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• v.46 no.1
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• pp.14-19
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• 2021

Various conditions such as pain or effusion of temporomandibular joint, degenerative condylar resorption, and articular disc displacement can be a cause of malocclusion. However, the reasons of occlusal changes are ambiguous in some patients. Unexpected occlusal change in patients with or without temporomandibular disorder (TMD) symptom was mostly caused by masticatory muscular disorders. This article reports two cases of recovery of occlusal relationship in TMDs patients after stabilization splint therapy. Stabilization splint therapy could be useful in certain conditions of occlusal changes in TMD.

• Journal of Sensor Science and Technology
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• v.32 no.6
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• pp.391-402
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• 2023

Low-dimensional (zero-dimensional (0-dim), 2-dimensional (2-dim)) nanoparticles, such as chalcogenide compound semiconductors, III-V semiconductors, transition metal dichalcogenides (TMDs), II-VI semiconductors, nanocarbons, hybrid quantum dots (QDs), and perovskite QDs (PQDs), for which blue light emission has been observed, are reviewed. Current synthesis and device fabrication technologies as well as their prospective applications on next-generation quantum-dot-based light-emitting diodes are discussed.