• Journal of Oral Medicine and Pain
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• v.25 no.3
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• pp.305-313
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• 2000

이 연구의 목적은 악관절 내장증 환자에서 관절원판의 형태를 자기공명영상사진으로 평가하고 임상적 증상과의 관계를 알아보고자 하는 것이다. 악관절 내장증의 증상을 가진 90명의 환자에서 169개의 관절을 자기공명영상사진으로 관절원판과 하악과두의 관계를 기준으로 정상군, 정복성 관절원판 변위군, 비정복성 관절원판 변위군으로 분류하고 관절원판의 형태를 5가지로 나누었다. 임상검사는 측두하악관절통과 관절음의 유무를 확인하여 그 상관관계를 알아보았다. 실험 결과에서 측두하악관절통은 각 군에서 관절원판의 형태와는 정상군을 제외하고는 통계적인 유의성이 없었으며, 염증성 삼출액과 유의한 관계를 보였다. 관절음은 정복성 관절원판 변위환자에서 관절원판형태와 통계적으로 유의성을 보였으며, 비정복성 관절원판 변위환자에서도 상당수 관절음이 발생하였음을 알 수 있었다. 이 결과는 측두하악관절의 통증은 관절원판의 형태가 많이 변형될수록 통증이 심해지는 경우가 많았지만, 다른 여러 가지 원인들이 존재할 수 있으며, 관절음은 정복성 관절원판 변위환자에서 관절원판의 변형이 심할수록 관절원판이 정복할 때 발생될 수 있다는 것을 의미한다. 따라서, 임상적인 검사와 더불어 자기공명영상사진으로 정확한 진단을 함으로써 관절원판 변위의 적절한 치료가 행해질수 있으리라 생각된다.

• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.54-76
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• 2024

Facet joint arthrosis is a progressive degenerative disease that is frequently associated with other spinal degenerative disorders such as degenerative disc disease or spinal stenosis. Lumbar facet joint arthrosis can induce pain in the proximal lower extremities. However, symptoms and imaging findings of "facet joint syndrome" are not specific as they mimic the pain from herniated discs or nerve root compression. Currently, evidence for therapeutic intra-articular lumbar facet joint injections is still considered low, with a weak recommendation strength. Nevertheless, some studies have reported therapeutic effectiveness of facet joint injections. Moreover, the use of therapeutic facet joint injections in clinical practice has increased. This review article includes opinions based on the authors' experience with facet joint injections. This review primarily aimed to investigate the efficacy of lumbar facet joint injections and consider their associated safety aspects.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.1
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• pp.1-9
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• 2012

Purpose: The purpose of this study was to investigate the effects of a mouthguard on stress distribution under mandibular impact. Materials and methods: The FEM model of head consisted of skull, maxilla, mandible, articular disc, teeth, and mouthguard. The impact locations on mandible were gnathion, the center of inferior border, and the anterior edge of gonial angle. And the impact directions were vertical, oblique ($45^{\circ}$), and horizontal. The impact load was 800 N for 0.1 sec. Results: When vertical impact was applied, the similar stress and the distribution pattern was occurred without the relation of the mouthguard use (P>.05). The model with mouthguard was dispersed the stress to the teeth, the facial bone and the skull when the oblique ($45^{\circ}$) impacts were happened. However, the stress was centralized on the teeth in the model without mouthguard(P<.05). The model with mouthguard was dispersed the stress to the teeth, the facial bone and the skull when the horizontal impacts was occurred. However, the stress was centralized on the teeth without mouthguard (P<.05). For all impact loads, stress concentrated on maxillary anterior teeth in model without mouthguard, on the contrary, the stress was low in the model with mouthguard and distributed broadly on maxillary anterior teeth, facial bone, and skull. Conclusion: The mouthguard was less effective at shock absorbing when vertical impact was added. However, it was approved that mouthguard absorbed the shock regarded to the oblique ($45^{\circ}$) and horizontal impact by dispersing the shock to the broader areas and decreasing the stress.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.1
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• pp.33-38
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• 2014

Purpose: To determine the therapeutic effectiveness of ultrasound-guided medial branch block (MBB) for the herniated lumbar disc patients who did not relieve their symptoms after percutaneous epidural neuroplasty (PEN). Materials and Methods: From August 2011 to February 2013, 559 patients with herniated lumbar disc have undergone PEN. Among them, ultrasound-guided MBBs were performed for the patients who had sustained low back pain and refered pain to lower extremities. Eighty eight patients were followed at 1 month and 39 patients could be followed at 6 month. All procedures have been performed by the one operator, and 23 G, 10 cm needle was placed and 0.5% lidocaine was injected under ultrasound guide. To target medial branches from L1 to L5, the groove at the root of transverse process and the base of superior articular process has been identified on transverse scan. Patients were evaluated by Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) at each follow-up. Significant pain relief was described as a 50% or more reduction in VAS and significant improvement in function was described as at least a 40% reduction in ODI. Results: VAS showed that preprocedure pain ($7.35{\pm}1.68$; $mean{\pm}SD$) significantly decreased 1 month after block ($3.36{\pm}2.98$) and 6 month ($3.05{\pm}2.27$) (p<0.05). ODI also showed that preprocedure score ($32.82{\pm}8.77$) significantly decreased at 1 month ($15.14{\pm}14.01$) and 6 month ($12.97{\pm}8.82$) (p<0.05). Significant pain relief was observed in 64.49% at 1 month and 64.10% at 6 month. Significant functional improvement in 59.81% at 1 month and 61.54% at 6 month. Conclusion: Ultrasound-guided medial branch block may sufficiently treat the facet problems secondary from disc disease.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.4
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• pp.245-256
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• 2001

The purpose of this study is to analyze the mechanical stress and displacement on the jaws during the simulated bilateral clenching task on the three-dimensional finite element model of the dentated skull with unilateral molar loss. For this study, the computed tomography(G.E.8800 Quick, USA) was used to scan the total length of human skull in the frontal plane at 2.0mm intervals. The fully assembled finite element model consists of the articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. The FE model was used to simulate the bilateral clenching in intercuspal position. The loading condition was the force of the masseter muscle exerted on the mandible as reported by Korioth et al. degrees of freedom of the zygomatic region where the masseter muscle is attached were fixed as restraints. In order to reflect the actual action of the muscles force, the displacement of the region was attached where the muscle is connected to the temporal bone and restraint conditions were given values identical to values at the attachment region of the masticatory muscle but with the opposite direction of the reaction from when the muscle force is acted on the mandible. Although the mandible generally has higher displacement and von Mises stress than the maxilla, its mandibular corpus on the molar-loss side has a higher stress and displacement than the molar-presence side. Because the displacement and von Mises Stress was the highest on the lateral surface of mandibular corpus with molar loss, the stress level of the condyle on the molar-loss side is greater than that of the molar-presence side, which in turn caused the symphysis of the mandible to bend. In conclusion, the unilateral posterior bite collapse with molar loss under para-functional activities such as bruxism and clenching can affect the stress concentration on the condyle and mandibular corpus. It is therefore necessary to consider the biomechanical function of dento-skeleton under masticatory force while designing the occlusal scheme of restoration on alveolar bone with the posterior collapse.

• The korean journal of orthodontics
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• v.20 no.2
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• pp.363-379
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• 1990

The purpose of this study was to evaluate the effects of the mandibular retractive force on the mandibular condyle of growing dog. The experimental animals were six mongrel dogs of two-month old. Their deciduous dentition were completed. Two of them was used as control group, and experimental group was composed of remaining four. Head band and chin cup were made of cotton tape, and hooks are fabricated on the chin cup and had band for closed coil. Mandibular retractive force was 100g/side and chin cap appliance was used for 14 hours/day during night. Experimental group were sacrificed at 2, 4, 6, 8 weeks from beginning of the experiment. Right TMJ was prepared for histologic study and left TMJ was examined grossly for disc, fossa, and condyle. The conclusions are: 1. Two-month old control animal showed active cartilaginous growth on the mandibular condyle, therefore showed thick proliferative and hypertrophic zones. Remodeling process in the condyle head was observed in which there were bone resorption on the anterior surface and bone apposition on the posterior surface. 2. Four-month old control animal showed marked reduction of hypertrophic zone but the condylar bone remodeling was more pronounced. 3. In experimental group, there are marked reduction of hypertrophic zone at 4 weeks from beginning of experiment, and hypertrophic zone disappeared at posterior-superior portion of condyle in 6-week experimental animal. 8 week experimental animal showed slight recovery of hypertrophic zone. 4. In experimental group, bone deposition was increased at anterior surface of condyle, and bone resorption was increased at posterior surface of condyle. 5. In control group, the glenoid fossa and surrounding bone showed mainly bone apposition. But experimental group showed bone resorption at anterior surface of articular eminence and increased bone apposition at posterior surface of postglenoid spine. 6. No marked traumatic change was seen but 4 weeks and 8 weeks experimental animal showed flattening of posterior surperior condylar surface. Bone marrow of condyle showed minute focal bleeding in 2 weeks and 4 weeks experimental animal, and congestion and depression of hematopoietic bone marrow during all experimental period.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.325-334
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• 2008

Statement of problem & Purpose: The purpose of this study was to investigate the effect of a mouth guard material properties on the skull and brain when they were under impact loads on mandible. Material and methods: Two customized mouth protectors having different material propeerst ieach other were made for a female Korean who had no history of brain trauma, no cerebral diseases, nomal occlusion and natural dentition. The 3D finite element model of human skull and brain scanned by means of computed tomography was constructed. The FEM model of head was composed of 407,825 elements and 82,138 nodes, including skull, brain, maxilla, mandible, articular disc, teeth and mouth guard. The stress concentrations on maxillary teeth, maxilla and skull with two mouth guards were evaluated under oblique impact load of 800N onto mandibular 3 loading points for 0.1sec. And the brain relative displacement was compared in two different mouth guard materials under same condition. Result and Conclusion: The results were as follows; 1. In comparison of von Mises stress on maxillary teeth, a soft mouth guard material had significantly lower stress values on measuring point than a hard mouth protector materials (P < .05). 2. In comparison of von Mises stress on maxilla and skull, A soft mouth protector material had significantly lower stress values on measuring point than a hard mouth protector materials (P < .05). 3. For impact loads on mandible, there were more stress concentrated area on maxilla and skull with hard mouth guard than soft with mouth protector. 4. For impact loads on mandible, brain relative displacement had little relation with mouth guard material properties. In results of this study, soft mouth guard materials were superior to hard mouth guard materials for mandible impact loads for prevention of sports injuries. Although the results of this study were not enough to figure out the roles of needed mouth guard material properties for a human head, we got some knowledge of the pattern about stress concentration and distribution on maxilla and skull for impact loads with soft or hard mouth protector. More studies are needed to substantiate the relationship between the mouth guard materials and sports injuries.