• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.209-216
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• 2018

This study aimed to investigate the association of the muscle activity around the neck of the operator(dental hygienists') according to the change in the patient's neck angle during a direct visual inspection on the maxillary right-side molar palatal surface. The operators were $4^{th}$ year dental hygiene students, who are future dentalhy gienists, having accurate understanding on and awareness of the location of the operation site, hand fixation, and how to use the tools. Data on the change in the muscle activity around the neck were collected by using surface electromyography and neck goniometer. SPSS statistics 20 was used for statistical analyses including Shapiro-wilk test and one-way ANOVA. As a result, the activities of the operator upper trapezius, cervical erector spinae, and levator scapulae muscles significantly decreased when the patient's head was angled compared to when it was not. For the angle of the operator head, the head bend significantly decreased when the patient's head was angled than when it was not. Based on the study results, it is expected that angling the patient's head when treating his or her teeth will decrease the excessive muscle activity around the neck of the operator, and will reduce muscle fatigue. Therefore, angling the head of the patient while treating his or her teeth is recommended. This suggests that muscle pain caused by repetitive actions in the wrong posture can be reduced.

• Korean Journal of Child Education & Care
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• v.19 no.3
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• pp.85-97
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• 2019

Objective: The purpose of this study was to find out any differences in teacher efficacy according to the perception and practices of the peers' supervision in day care centers, and to improve the effectiveness of teachers and the quality educare. Methods: The subjects were 301 teachers at daycare centers in Gyeonggi Province who are working at public, private, workplace and home daycare centers. The instruments used were questionnaire concerning the perceptions and practices of peers' supervision in day care centers, and the teacher efficacy instrument. Results: The differences in teacher efficacy according to the perception of peers' supervision were significant, depending on the level of perception, willingness to participate, need and satisfaction, and sub-area of the main view. And, the differences in teacher efficacy according to the practices of peers' supervision were significant, depending on the numbers received, gave and implementated, the implementators, and the type of peers' supervision. Conclusion/Implications: This can be a clear benefit for stimulating peer's supervision. This study can greatly benefit the quality of day care service and improve teacher's professionalism.

• Journal of the Korean Society of Radiology
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• v.14 no.7
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• pp.981-989
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• 2020

In this study, a self-made customized phantom was used to quantitatively measure the change in CT number and noise according to the change of pitch. In order to acquire an image using the phantom, the inside of the phantom was filled with sterile distilled water. Inside the glass tube, a solution obtained by diluting the ratio of normal saline and contrast medium to 100%(NS), 400:1, 200:1, 100:1, 50:1, respectively, was placed and imaged. At this time, the pitch was divided into steps of 0, 0.35, 0.7, 1.05, and 1.4 for each dilution ratio of the solution and imaged, respectively. One-way ANOVA analysis were performed to verify whether the mean of the CT number and noise values measured in all ROIs by dilution ratio showed a significant difference according to the change in pitch. As a result of the experiment, there was no statistically significant difference in the change of the CT number according to the change in the pitch for each dilution ratio, but the noise value tended to increase with the increase of the pitch, and showed a statistically significant difference. In the spiral image acquisition of CT, noise can be changed to a significant level depending on the pitch. Therefore, it will be necessary to set the quality evaluation items and criteria for CT images using the spiral image acquisition method.

• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.211-222
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• 2003

The purpose of this study was to determine whether there is an association between disk displacement of the Temporomandibular Joint (TMJ) and dentofacial asymmetry In orthodontic patients. The subjects consisted of 60 female orthodontic patients between the ages of 18 and 38 years (mean age 23.3 years) who had visited the Department of Orthodontics at Seoul National University Dental Hospital from January 2000 to April 2002. On the basis of magnetic resonance imaging (MRI) of their bilateral TMJs, the subjects were divided Into four groups'. bilateral normal group (twenty-one persons); disk displacement of right TMJ group (six persons); disk displacement of left TMJ group (nine persons); and disk displacement of both TMJs group (twenty-four persons) Postero-anterior (PA) cephalograms and diagnostic models which had been taken before orthodontic treatment were measured. In the linear measurements, a line connecting the right and left Latero-Orbitale (Lo) represented the horizontal reference line (H). The vertical reference line (V) was constructed as a line bisecting and running perpendicular to H. One-way analysis of variance (ANOVA) was used to test whether the mean values of measurements between groups were significantly different. In addition, Bonferronil's multiple comparison test was performed at a level of 0.05. The results were as follows; 1 In the diagnostic model analysis, the overjet, nght molar relationship, and left molar relationship were significantly different among the four groups. 2. In the PA cephalometric analysis, differences in the right and left vertical position of the lower first molar and Ag were significantly dissimilar among the four groups. 3. If the disk displacement of TMJ was present on one side, the ipsilateral ramus was shorter, resulting in asymmetry in the vertical position of Ag. This study indicated that dentofacial asymmetry might be related to the disk displacement of TMJ.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.919-926
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• 2021

In this study, we wanted to find out the optimal angle as a modified tangential projection of the patella. In the experiment, we used Kyoto Kagaku's PBU-50 phantom. In the supine position, the F-T angle was set to 95°, 105°, 115°, 125°, 135°, 145°, and Patella tangential projection images were obtained by varying the X-ray tube angle by 5° so that the angle between the X-ray centerline and tibia at each angle was 5~20°. Image J was used for image analysis and the congruence angle, lateral patellofemoral angle, patellofemoral index and contrast to noise ratio(CNR) were also measured. SPSS 22 was used for statistical analysis, and the mean values of congruence angle, patellofemoral angle, patellofemoral index, and CNR were compared with Merchant method through one-way batch analysis and corresponding sample t-test. As a result of the study, in the case of congruence angle, the angle of incidence of the knee-angle X-ray centerline was 105°-72.5° (20° tangential irradiation), 115°-72.5°, 77.5° (15, 20° tangential irradiation), 125°-82.5° (20° tangential irradiation), lateral patellofemoral angle is 115°-72.5°, 77.5° (15, 20° tangential irradiation), 125°-72.5° (10° tangential irradiation), patellofemoral index is 115°-72.5° (15° tangential irradiation) and 125°-72.5° (10° tangential irradiation) were not significantly different from Merchant method (p> .05). In case of CNR, it is not different from Merchant method at 105°-67.5°, 72.5° (15, 20° tangential irradiation), 115°-67.5°, 72.5°, 77.5° (10, 15, 20° tangential irradiation). (P> .05). Based on the results of this study, high diagnostic value images can be obtained by setting the knee angle and the angle of incidence of the X-ray tube to 115°-72.5° (15° tangential irradiation) during the modified tangential examination of the knee bone. It was confirmed.

• Journal of Korean Academy of Dental Administration
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• v.5 no.1
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• pp.31-37
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• 2017

Recently interest in infection control is increasing in hospitalsnfection control has become more important in the overall health care practiceental hospital also requires thorough infection control. There are various kinds of vectormedical clothing. Contaminated clothing of a hospital staff can be a vector of nosocomial infecton. actual case of nosocomial infecton caused by contaminated medical clothing, nursing students were measuring contamination levels of uniforms and pathogenic microorganism wdetected in front of the uniform and pocket. There is also a high risk of exposure to contamination in the dental hospital. We conducted a study to enhance awareness about infection and proper clothing management by comparing before and after contamination of clothing caused by aerosols produced during scaling. Subjects were scaling operators' uniforms in the department of dental hygiene, K University located in Daejeon. Before scaling, the uniform was sterilized by autoclavecaling was performed times in the same place (an average of 60 minutes per person, a total of 180 minutes). ive parts of the uniform (sleeves, chest, belly, thigh, edge of pants) contracted Rodak-plate for 15 seconds. After incubating the contacted Rodak-plate at 37℃ incubator, contamination levels by measuring the number of colonies. As a result, all parts increased number of colonies. ontamination order chestedge of pants thigh belly sleeves. Increase rate of colonies was also high in the order chest edge of pants thigh belly sleeves. This study showed seriousness of clothing contaminationcaused by aerol produced during scalingcontamination of clothing can be a path to nosocomial infecton. According to th study, infection control for clothing as well as dental instruments should be implemented and thorough infection control training needed for dental staff. In further researches, practical infection prevention supplementing clothing management method.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.395-404
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• 2021

Purpose. The purpose of present study was to evaluate the effect of changing structural stability of wax disc on the fit of prosthesis when the milling proceeded in order. Materials and methods. Prepared maxillary left first molar was used to fabricate a Ni-Cr alloy reference model. This was scanned to design crown and then wax pattern was milled, invested and cast to fabricate prosthesis. The wax patterns located in a row centrally within a single wax disc were set into a total of five groups ranging from WM1 group that was first milled to WM5 group that was last milled and the number of each group was set as 10. Silicone replica technique was used to measure the marginal gap, axial internal gap, line angle internal gap, occlusal internal gap. Data was evaluated with one-way ANOVA with significance level set at α = .05 and then Tukey HSD test was conducted for post analysis. Results. Marginal gap measured in each group, it was 40.41 ± 2.15 ㎛ in WM1 group, 40.44 ± 2.23 ㎛ in WM2 group, 39.96 ± 2.25 ㎛ in WM3 group, 39.96 ± 2.48 ㎛ in WM4 group, and 40.57 ± 2.53 ㎛ in WM5 group. No significant difference was found between groups. The significant difference between the groups was also not found in the axial internal gap, line angle internal gap, and occlusal internal gap. Conclusion. Internal and marginal fit of single crown to the sequential order of milling processing in the single machinable wax disc did not seem to be affected by the sequence.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.2
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• pp.93-102
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• 2016

Purpose: The aim of this study was to evaluate the fit accuracy of two zirconia and titanium abutments in internal hexagonal implants. Materials and methods: One titanium abutment and two zirconia abutments were tested in internal hexagonal implants (TSV, Zimmer). Prefabricated zirconia abutments (ZirAce, Acucera) and customized zirconia abutments milled by the Zirkonzahn system (Zirkonzahn Max, Zirkonzahn) were selected and prefabricated titanium abutments (Hex-Lock, Zimmer) were used as a control. Eight abutments per group were connected to implants with 30 Ncm torque. The marginal gaps at abutment-implant interface, the internal gaps at internal hex, vertical and horizontal gaps between screws and screw seats in abutments were measured after sectioning the embedded specimens using a scanning electron microscope. Data analysis included one-way analysis of variance and the Scheffe test (n=16, ${\alpha}=0.05$). Results: The mean marginal gap of customized zirconia abutment was higher than those of two prefabricated zirconia and titanium abutments. The internal gaps at internal hex showed no significant differences between customized and prefabricated abutments and were higher than those of prefabricated titanium abutments. The mean vertical and horizontal gaps at screw in prefabricated zirconia abutment were higher than those of prefabricated titanium abutment. In the case of customized zirconia abutment, the mean horizontal gap at screw was higher than those of both the prefabricated zirconia and the titanium abutment but the mean vertical gap was not even measureable. The screw seats were clearly formed but did not match with abutment screws in prefabricated zirconia abutments. They were not, however, precisely formed in the case of customized zirconia abutments. Conclusion: Within the limitations of this study, the prefabricated titanium abutments showed better fit than the zirconia abutments, regardless of customized or prefabricated. Also, the customized zirconia abutments showed significantly higher marginal gaps and the fit was less accurate between screws and screw seats than the prefabricated abutments, titanium and zirconia.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.231-239
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• 2013

Purpose: To design and fabricate the auto pattern maker for the development. Methods: we got the necessary data, needed in design, by using CAD. Based on the these data, we fabricated the trial product for the development of the auto pattern maker. Results: The auto pattern maker were composed with combinations of many elements; pattern making assembly, control panel, frame attachment and prober unit. The pattern making assembly was comprised of the cutter, the pattern holder, pattern remover and silence cover which could minimize the sound during the cutting process. The control panel was designed to be connected and operated with the main printed circuit board. The prober could get the eye shape data by scanning of 1.8 degrees around the groove of the frame through the encoding data according to the address. After starting, scanning was carried out in two passes, i.e. one right-handed and one left-handed. Communication connector could send the eye shape data from auto pattern maker to outer system with the RS232C transmission system. By using the one-way analysis of variance, we got the error rate of cut pattern size for ${\Phi}22mm$, ${\Phi}55mm$ and ${\Phi}62mm$. Because F-value was 0.510 and p-value was 0.601, no statistically significant differences were found. Also, the mean cutting error of the auto pattern maker was 0.0274 mm. Conclusions: we could succeed in making the trial product by applying it to the development of the auto pattern maker. The role of this auto pattern maker is to find a exact required size of lens to fit the frame by measuring the frame. The acquired data are transferred to outer system for grinding and finishing with patternless process. Also, the trial product can produce pattern to fit the frame. Therefore, it was confidently expected that the optometrists could handily produce pattern to fit the frame with this trial product and dispense the ophthalmic lens because of its efficiency and convenience compared to the past.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.501-507
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• 2017

The shortage of dental hygienists has been a long-standing problem in Korea. Small-scaled dental clinics suffer from a lack of dental hygienists, who seem to prefer working at large-scaled dental clinics. The purpose of this study was to confirm the differences in the working conditions according to the scales of dental clinics. We collected the working information registered via job advertisements through the web-sites of Korean Dental Hygienists Association, Dental Jobs, and Nurse Jobs from July to August 2016. The results were as follows: 96.7% of the advertisements wanted regular workers, while the proportion of part-time workers was the highest (34.8%) in the group with less than 3 employees. The average workdays per week was $5.32{\pm}0.55$ days, and the group with less than 3 employees had significantly longer workdays than the other groups. The daily working time was $8.99{\pm}0.44$ hours, and there was no difference among the groups. Night overtime hours were needed by 54.4%, 45.0%, and 31.3% of the groups with of the groups with 4~7 employees, more than 8 employees, and less than 3 employees, respectively. Information regarding annual leave (60.5%), monthly leave (63.9%), half a day off (32.4%) and vacations (43.1%) were presented in the job advertisements, and these proportions were significantly higher by the group with more than 8 employees. Information on overtime pay (14.4%), night-work pay (13.4%), incentives (34.1%), lunches (60.2%), vacation bonuses (33.8%), and self-development (20.4%) were presented in job advertisements. The group with 4~7 employees had significantly higher proportions in severance pay, vacation bonuses, self-development, and major national insurance. It is necessary to consider the improvement of working conditions, diversity of working styles, and welfare of dental hygienists, and it is suggested that small dental clinics provide more precise working conditions.