• The Journal of Advanced Prosthodontics
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• 제14권6호
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• pp.346-359
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• 2022

PURPOSE. Four and six implant-supported fixed full-arch prostheses with various framework materials were assessed under different loading conditions. MATERIALS AND METHODS. In the edentulous maxilla, the implants were positioned in a configuration of four to six implant modalities. CoCr, Ti, ZrO₂, and PEEK materials were used to produce the prosthetic structure. Using finite element stress analysis, the first molar was subjected to a 200 N axial and 45° oblique force. Stresses were measured on the bone, implants, abutment screw, abutment, and prosthetic screw. The Von Mises, maximum, and minimum principal stress values were calculated and compared. RESULTS. The maximum and minimum principal stresses in bone were determined as CoCr < ZrO₂ < Ti < PEEK. The Von Mises stresses on the implant, implant screw, abutment, and prosthetic screws were determined as CoCr < ZrO₂ < Ti < PEEK. The highest Von Mises stress was 9584.4 Mpa in PEEK material on the prosthetic screw under 4 implant-oblique loading. The highest maximum principal stress value in bone was found to be 120.89 Mpa, for PEEK in 4 implant-oblique loading. CONCLUSION. For four and six implant-supported structures, and depending on the loading condition, the system accumulated different stresses. The distribution of stress was reduced in materials with a high elastic modulus. When choosing materials for implant-supported fixed prostheses, it is essential to consider both the number of implants and the mechanical and physical attributes of the framework material.

• Journal of Veterinary Science
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• 제21권5호
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• pp.69.1-69.11
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• 2020

Background: An inappropriate Q angle may affect the biomechanics of the canine patellofemoral joint. Objectives: The purpose of this study was to evaluate the effects of changes in quadriceps angle (Q angle) on patellofemoral joint pressure distribution in dogs. Methods: Eight stifles were positioned at 45, 60, 75, 90, 105, and 120° of flexion in vitro, and 30% body weight was applied through the quadriceps. Patellofemoral contact pressure distribution was mapped and quantified using pressure-sensitive film. For the pressure area, mean pressure, peak pressure, medial peak pressure, and lateral peak pressure, differences between groups according to conditions for changing the Q angle were statistically compared. Results: Increases of 10° of the Q angle result in increases in the pressure area (P = 0.04), mean pressure (P = 0.003), peak pressure, and medial peak pressure (P ≤ 0.01). Increasing the Q angle by 20° increases the pressure area (P = 0.021), mean pressure (P ≤ 0.001), peak pressure (P ≤ 0.01), and medial peak pressure (P ≤ 0.01) significantly, and shows higher mean (P ≤ 0.001) and peak pressures than increasing by 10°. Decreasing the Q angle increases the mean pressure (P = 0.013), peak pressure, and lateral peak pressure (P ≤ 0.001). Conclusions: Both increases and decreases in the Q angle were associated with increased peak patellofemoral pressure, which could contribute to the overloading of the cartilage. Therefore, the abnormal Q angle should be corrected to the physiologically normal value during patellar luxation repair and overcorrection should be avoided.

• Clinical Pain
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• 제20권1호
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• pp.49-52
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• 2021

Bertolotti's syndrome (BS) refers to chronic low back pain (LBP) associated with lumbosacral transitional vertebrae (LSTV). Many studies suggest that the anomalous articulation alters biomechanics, resulting in discomfort on the ipsilateral side. Herein, we present an unusual case of BS presenting pain on the non-articulated side. A 46-year-old man visited our clinic with history of chronic LBP, refractory to treatment of analgesics, modalities and manual therapies. Electrodiagnostic studies showed no evidence of lumbosacral radiculopathy. Radiographies noted unilateral pseudoarticulation of L5~S1 vertebrae, on the contralateral side of his pain. The pain improved dramatically after sacroiliac joint block and facet joint block with iliolumbar ligament infiltration on the non-articulated side. Clinicians should be cautious that the unaffected joint in BS may serve an important role in altered lumbopelvic biomechanism, since it might eventually lead to intractable chronic LBP when overlooked.

• Clinics in Shoulder and Elbow
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• 제24권3호
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• pp.141-146
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• 2021

Background: The purpose of the present study was to determine how long superior screws alone or in combination with posterior placement of metaglene screws protruding and penetrating into the scapular spine in reverse total shoulder arthroplasty affect the strength of the scapular spine in a fresh cadaveric scapular model. Methods: Seven fresh cadaver scapulas were allocated to the control group (short posterior and superior screws) and seven scapulars to the study group (spine base fixation with a four long screws, three with both long superior and long posterior screws). Results: The failure load was lower in the spine fixation group (long screw, 869 N vs. short screw, 1,123 N); however, this difference did not reach statistical significance (p>0.05). All outside-in long superior or superior plus posterior screws failed due to scapular spine base fracture; failures in the short screw group were due to acromion fracture. An additional posterior outside-in screw failed to significantly decrease the failure load of the acromion spine. Conclusions: The present study highlights the significance of preventing a cortical breach or an outside-in configuration when a superior or posterior screw is inserted into the scapular spine base.

• 대한정형도수물리치료학회지
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• 제29권2호
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• pp.39-48
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• 2023

Background: The position of pitcher requires a lot of repetitive motion, and because of this, it is known that not only professional baseball players, but also middle and high school players are frequently exposed to injuries in baseball. The purpose of this study is to examine the differences in upper extremity muscle activity during repeated pitching and the activity of each muscle during repeated pitching by analyzing middle and high school pitchers, divided into groups by age. Methods: Twenty participants (10 middle school male students and 10 high school male students) were recruited for this research. The outcome measures included neuromuscular motor control, including the upper trapezius (UT), triceps brachii (TB), deltoid (DT), latissimus dorsi (LD), biceps brachii (BB), pectoralis major(PM), extensor carpi radialis(ER), and flexor carpi radialis (FR). Results: The two-way analysis of varaince (ANOVA) was used to compare the muscle activity variables between the middle school and high school students. The one-way ANOVA was used to compare the muscle activity variables within time differences each groups. Conclusion: Our results provided promising clinical evidence that guide for upper extremity muscles to increase pitching efficiency in middle and high school base ball players.

• Physical Therapy Rehabilitation Science
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• 제11권4호
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• pp.436-445
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• 2022

Objective: Deformation of soft tissues around the neck and scapularcan caused by forward head posture(FHP), which has an uncomfortable effect on biomechanical changes in the scapula as well as functional disorders of the shoulder. However, studies related to direct FHP, biomechanical changes in the scapulafunction, and shoulder pain and disorder have not yet been conducted. Therefore, purpose of this study is to effect of decresedthe FHP on the shoulder function of the sacpular biomechanical examine the change in the shoulder painand disorder. Design: A randomized controlled trial Methods: The participants were 32adults(23.03±3.90 years) recruited and redivided randomly into Forward head posture corrective exercise(FHPCE) vs Control. The FHPCE group was proceeded according to the over load principle through 2steps biofeedback exercise and corrective exercise(n=16). The control (n=16) was TENS did not operated and padding 20 minute. This study was conducted 3 times a week for 4a weeks. Results: FHPCE group is improve in the results of craneocervical angle(p<0.05, 95% CI: 0.352, 4.073). In Mechanical changes of scapula in the shoulder flexion more significant improvement in FHPCE than control group[Axis X(p<0.05), Y(p<0.01), Z(p<0.01)], and shoulder abductionmore significant improvement in FHPCE than control group[xis X(p<0.01)], as well FHPCE showed significant increased in the results in the shoulder pain(p<0.05, 95% CI: -13.244, -1.566) Conclusions: This study suggected that FHP affects the biomechanical changes of the shoulder, and a new method for shoulder pain intervention

• Physical Therapy Rehabilitation Science
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• 제12권2호
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• pp.130-139
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• 2023

Objective: This study aimed to analyze the effects and characteristics of the height of the treatment table on the force and time of ground reaction (GR) and contact hand (CH) generated from the therapist's feet to generate thrust during spinal manipulation (SM). Design: A cross-sectional survey study Methods: Thirty-six healthy subjects were recruited. SM was performed on the ilium using a knee-high table, where the therapist felt it was easy to control the subject's posture and body shape and comfortable to generate force, as well as a relatively high thigh-high table. The force and time generated by the therapist's GR and CH were simultaneously measured through a force plate. Results: As a result, there was a significant difference in peak force and rundown force at the therapist's GR according to the table height (p < 0.05). In the therapist's CH, there was a significant difference between PreMin (preload minimum) force and peak force (p < 0.05), and there was a significant difference between the time from PreMin to peak and the time of the entire section (p < 0.05). Conclusions: As a result, the generation of increased CH force and faster thrust duration were confirmed by mobilizing the reduced GR force of the therapist to generate thrust than the relatively high table on the knee-high table.

• The Journal of Korean Physical Therapy
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• 제35권5호
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• pp.132-138
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• 2023

Purpose: This study compared the effects of the elastic resistance and general training for college Taekwondo athletes, and investigated the biomechanical ability and lower extremity function according to the movement speed of the knee joint. Methods: Twenty university student Taekwondo athletes participated voluntarily in this study. The subjects performed general resistance training for four weeks, followed by elastic resistance training for another four weeks. The biomechanical parameters during the fast and slow isokinetic conditions, Y-balance ability, and vertical jump ability were measured three times: before training, after general resistance training, and after elastic resistance training. Statistical analysis was performed under isokinetic conditions and the intervention effect. Results: The biomechanical ability differed significantly between fast and slow isokinetic conditions (p<0.05). An analysis of the training method revealed a significant difference in the maximum knee extension speed and the posterior-lateral direction of the Y-balance test (p<0.05). Conclusion: Elastic resistance training had a more positive effect on the functional task performance than biomechanical factors related to muscular strength compared to general resistance training. In addition, speed-related knee biomechanical information of subjects with strong physical abilities could be utilized in sports physiotherapy.

• Korean Journal of Radiology
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• 제23권6호
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• pp.674-687
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• 2022

Patellofemoral instability (PFI) is common in pediatric knee injuries. PFI results from loss of balance in the dynamic relationship of the patella in the femoral trochlear groove. Patellar lateral dislocation, which is at the extreme of the PFI, results from medial stabilizer injury and leads to the patella hitting the lateral femoral condyle. Multiple contributing factors to PFI have been described, including anatomical variants and altered biomechanics. Femoral condyle dysplasia is a major risk factor for PFI. Medial stabilizer injury contributes to PFI by creating an imbalance in dynamic vectors of the patella. Increased Q angle, femoral anteversion, and lateral insertion of the patellar tendon are additional contributing factors that affect dynamic vectors on the patella. An imbalance in the dynamics results in patellofemoral malalignment, which can be recognized by the presence of patella alta, patellar lateral tilt, and lateral subluxation. Dynamic cross-sectional images are useful for in vivo tracking of the patella in patients with PFI. Therapeutic approaches aim to restore normal patellofemoral dynamics and prevent persistent PFI. In this article, the imaging findings of PFI, including risk factors and characteristic findings of acute lateral patellar dislocation, are reviewed. Non-surgical and surgical approaches to PFI in pediatric patients are discussed.

• Korean Chemical Engineering Research
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• 제47권5호
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• pp.538-545
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• 2009

본 총설에서는 주사형프로브현미경의 원리와 응용에 관하여 간략히 설명하고 최근 본 그룹에 의하여 활발하게 연구되고 있는 나노탐침과 AFM(원자간력현미경 atomic force microscopy)을 이용한 저침습성(low-invasive) 단일세포 조작기술과 고효율 유전자 도입기술을 소개하고자 한다. 시판 AFM 탐침을 침상구조로 가공한 나노탐침과 AFM을 이용하였을 경우, 탐침의 세포삽입의 성공여부를 force-distance curve 상의 척력소실의 유무로 판단할 수 있다. 침상 나노탐침을 사용하면 대부분의 세포에서 80~90%의 고효율 세포삽입이 가능하여 마이크로인젝션용 미세관을 이용하는 경우보다 세포삽입효율이 높았다. 또한 나노탐침의 직경이 400 nm 이하의 경우에는 세포 종류에 관계없이 장시간 나노탐침의 삽입에도 세포활성에 큰 영향이 없었다. 침상나노탐침을 이용하여 DNA를 도입하였을 경우에도 기존의 DNA 도입방법과 비교하여 높은 도입효율과 유전자 발현율로 DNA를 도입할 수 있는 가능성을 확인하였다.