• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.21 no.1
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• pp.43-47
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• 2015

Background: The purpose of this study was to identify the effects of the blood flow on carotid and vertebral artery during the forward shift on head. Methods: A 20-year female healthy subject participated in this study. This study was set up the forward shift on head at the 3cm and 6cm in a shoulder midline (acromion). Measurement method were using duplex ultrasound with colour doppler imaging for the blood flow on carotid and vertebral artery. Results: Carotid artery was increased the blood flow and vertebral artery was decreased the blood flow during forward shift on head. Conclusions: These findings suggest that carotid and vertebral artery changes to the blood flow during forward shift on head. Therefore, we should be consider that hemodynamic factor when apply to the therapeutic exercise for patients of forward head posture.

• The Journal of Advanced Prosthodontics
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• v.10 no.6
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• pp.401-407
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• 2018

PURPOSE. When performing an occlusal procedure, it is recommended that the patient should be sitting straight with the head in a natural position. An inappropriate mandibular position caused by an incorrect occlusal record registration or occlusal adjustment can result in damaged teeth and cause functional disorders in muscles and temporomandibular joints. The purpose of this study was to clarify the influence of horizontal cephalic rotation on mandibular position by investigating the three-dimensional positions of condylar and incisal points. MATERIALS AND METHODS. A three-dimensional jaw movement measurement device with six degrees of freedom (the WinJaw System) was used to measure condylar and incisal points. The subjects were asked to sit straight with the head in a natural position. The subjects were then instructed to rotate their head horizontally $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, $40^{\circ}$, $50^{\circ}$and $60^{\circ}$ in the right or left direction. RESULTS. The results indicated that horizontal cephalic rotation made the condyle on the rotating side shift forward, downward, and toward the inside, and the condyle on the counter rotating side shift backward, upward, and toward the outside. Significant differences in deviations were found for angles of rotation higher than $20^{\circ}$. The incisal point shifted in the forward and counterrotating directions, and significant differences were found for angles of rotation higher than $20^{\circ}$. CONCLUSION. The mandibular position was altered by horizontal cephalic rotations of more than $20^{\circ}$. It is essential to consider the possibility of deviation of the mandibular position during occlusal procedures.

• Wind and Structures
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• v.27 no.5
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• pp.347-356
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• 2018

In this paper, stress distribution for a structurally stable greenhouse is considered in the present paper with subsequent investigation into the detailed stress distribution contour with the variation of self-weight and wind pressure level designation method under wind velocity of less than 30 m/sec. For reliable analysis, wind pressure coefficients of a single greenhouse unit were modeled and compared with experiment with correlation coefficient greater than 0.99. Wind load level was designated twofold: direct mapping of fluid dynamic analysis and conversion of modeled results into wind pressure coefficients ($C_P$). Finally, design criteria of EN1991-1-4 and NEN3859 were applied in terms of their wind pressure coefficients for comparison. $C_P$ of CFD result was low in the most of the modeled area but was high only in the first roof wind facing and the last lee facing areas. Besides, structural analysis results were similar in terms of stress distribution as per EN and direct mapping while NEN revealed higher level of stress for the last roof area. The maximum stress levels are arranged in decreasing order of mapping, EN, and NEN, generating 8% error observed between the EN and mapping results under 30 m/sec of wind velocity. On the other hand, effect of dead weight on the stress distribution was investigated via variation of high stress position with wind velocity, confirming shift of such position from the center to the forward head wind direction. The sensitivity of stress for wind velocity was less than 0.8% and negligible at wind velocity greater than 20 m/sec, thus eliminating self-weight effect.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.413-418
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• 2009

This study was to investigate the muscoulosckeletla pain from 214 dental hygienist during treatment process in Ulsan and Kyungnam. The data collection was done from March to May in 2009 with questionnaire. The study results were as follows. In the participant's age characteristic, under 23 years old(34.1%) was majority, other participant age group were 24~26 years old(33.6%), 25~29 years old(20.6%), and over 30 years old(11.7%). Other participant characteristic were unmarried participant(86.4%), none religion(43.5%), and graduation from college(88.3%). In the participant's business characteristic, working place were dental clinic(57.5%), and dental hospital(42.5%), career was 1~2 years(42.5%) and a number of change job was once(45.1%). Salary were 1,300,000~1,490,000 won (33.6%), 1,500,000~1,990,000 won(29.9%), under 1,300,000 won(26.2%), 2,000,000~2,490,000 won(7.5%). A number of dental hygienist was over 20 person(85.9%) and the average dental hygienist was 15.6 person. A number of dentist were one person(28.5%), 2 person(22.4%), 4 person(19.2%) and the average dentist was 3.2 person. Dental hygienist's working hour was 8~9(49.5%), a large part of dental hygienist was assistance of general treatment(70.1%). Other results were 5 days/week working(60.3%), and night shift(49.1%). In an effect of musculoskeletal pain during working, neck pain was significantly influenced by body posture such as "head forward 15 degree or head round", "non balanced shoulders", "bend waist", "bend wrist", and "sit astraddle on a chair". Shoulders pain was significantly influenced by body posture such as "head forward over 15 degree", "bend waist", and "stand up straightly". Knee pain was significantly influenced by body posture such as "stand up straightly", and hip pain was influenced by "sit astraddle on chair".