• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.539-547
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• 2020

Objectives: This study was performed to emphasize improvement of the perception of dental hygienists' environmental working conditions by analyzing various factors. Methods: Two hundred ninety-eight female dental hygienists working at 35 medical institutions in Daegu City and Gyeongsangbuk-do Province participated. A self-recording type survey was done in October 2016. Results: Factors influencing the perception of infection control was length of career. Dental hygienists with more experience have a higher level of perception. Factors influencing the perception of working posture was the number of patients per day and career level. Dental hygienists seeing 50 or fewer patients per day and senior staff showed higher levels of this perception. Factors influencing the perception of noise in the working area were length of career and lunchtime break. The perception level was high in the group with longer careers and dental hygienists who rest at lunch time. Factors influencing chemical exposure during work were the number of patients per day and the type of institute. Dental hygienists working in dental clinics or dealing with more patients had lower levels of perception. Conclusions: The sociodemographic and working characteristics of dental hygienists influence the perception of dental hygienists' environmental working conditions.

• Journal of dental hygiene science
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• v.24 no.3
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• pp.152-159
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• 2024

Background: As interest in health increases, the number of people engaging in weight training to enhance muscle strength and muscle mass is on the rise. High-intensity weight training has been reported to induce tooth clenching habits, leading to tooth damage and temporomandibular joint (TMJ) abnormalities. Consequently, it is essential to investigate the impact of weight training accompanied by tooth clenching on oral health and to develop guidelines based on these findings. Methods: The study included male participants aged 25 years and older, comprising 15 non-exercisers and 15 professional fitness trainers who have been engaged in weight training for over 5 years. Data were collected using a self-administered questionnaire to gather information on age, exercise experience, total weight lifted in three major weight training exercises (deadlift, bench press, and squat), and teeth clenching habits. Additionally, examinations for tooth cracks and fractures, TMJ noise and pain, maximum mouth opening, occlusal force, and occlusal contact area were conducted. Results: Compared to non-exercisers, professional fitness trainers who have been engaged in weight training for over 5 years exhibited a higher prevalence of teeth clenching habits. While there were no significant differences between the two groups in occlusal contact area and the extent of tooth fractures, there were significant differences in occlusal force and the degree of tooth cracks. Furthermore, unlike joint noise and TMJ pain, the maximum mouth opening was significantly reduced in professional fitness trainers compared to non-exercisers. Conclusion: Our study suggests that the continuation of high-intensity exercise, which induces teeth clenching habits, may cause tooth damage and TMJ disorders.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.185-190
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• 2013

Purpose: The aim of the present study was to evaluate the measurement accuracy of endodontic file length on periapical digital radiography after application of noise reduction digital enhancement. Materials and Methods: Thirty-five human single-rooted permanent teeth with canals measuring 20-24 mm in length were selected. ISO #08 endodontic files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the standard value. Standard periapical digital images were obtained using the Digora digital radiographic system and a dental X-ray unit. In order to produce the enhanced images, the noise reduction option was applied. Two blinded radiologists measured the file lengths on the original and enhanced images. The measurements were compared by repeated measures ANOVA and the Bonferroni test (${\alpha}=0.05$). Results: Both the original and enhanced digital images provided significantly longer measurements compared with the standard value (P<0.05). There were no significant differences between the measurement accuracy of the original and enhanced images (P>0.05). Conclusion: Noise reduction digital enhancement did not influence the measurement accuracy of the length of the thin endodontic files on the digital periapical radiographs despite the fact that noise reduction could result in the elimination of fine details of the images.

• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.158-164
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• 2019

Recently many studies to reduce the noise of dental hand piece which generate inevitably mechanical sound to offend to the ear of a patient have been spotlighted. Generally, methods of adding a sound absorbing material inside the exhaust valve, air pump of machine or automobile are widely reported as optimal way to reduce the mechanical noise. In this paper we studied a new UV laser aided manufacturing of micro-porous structure of EPP substrate and applied dental hand piece to improve the efficiency of sound absorption. A lot of micro-sized pores were fabricated with UV laser processing on the surface of sliced EPP substrate. From fundamental experiments, more high-performance of micro-porous EPP substrate has finally demonstrated for sound-absorbing structure of the micro muffler inside dental hand piece, which actually has the excellent potential to apply a lot of potable machine.

• Journal of dental hygiene science
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• v.19 no.1
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• pp.31-38
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• 2019

Background: This study aimed to investigate the effects of critical thinking and good communication skills on the problem-solving abilities of dental hygiene students. Methods: A total of 508 dental hygiene students were convenience-sampled from 3 universities. Results: The results revealed that critical thinking had the highest intellectual fairness score of 3.60, and systematicity was the lowest at 3.19. The values for communication skills were high in reaction, social adequacy, and concentration, with an average of 3.65. Problem-solving abilities were in the following order: clarification of the problem, seeking solutions, and decision making. According to general characteristics, more extroverted personalities possessed higher levels of critical thinking, communication skills, and problem-solving abilities (p<0.01). Critical thinking scores were high (p=0.016) in students who responded that peer relationship was difficult; however, their communication skills were the lowest (p<0.001). Additionally, problem-solving abilities were highest among students who reported a difficult peer relationship (p=0.001). The higher the satisfaction with dental hygiene academics, the higher the critical thinking, communication skill, and problem-solving ability (p<0.001). Critical thinking showed a high positive correlation with variables in the following order: clarification of the problem, performing the solutions, seeking solutions, decision making, and evaluation and reflection. The communication skills were also related to these variables listed above (p<0.01). With critical thinking, confidence, watchfulness, intellectual passion/curiosity, sound skepticism, objectivity, and systematicity all influenced the problem-solving ability. Conclusion: Communication skills were influenced by noise control, putting on the other's shoe, social tensions, and efficiency, which affected the problem-solving ability. Dental clinics require dental hygienists to have critical thinking to make analytical judgments and effective communication skills to solve human relation problems with patients and care-givers. Therefore, these skills should be developed in dental hygiene students to improve their problem-solving abilities.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.269-277
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• 2017

Purpose: The aim of this study is to compare the performance of two piezoelectric engine systems by surveying satisfaction from dental clinicians. Materials and Methods: Two piezoelectric systems were evaluated: TRAUS XUS10 (Saeshin), PIEZOSURGERY touch (Mectron). For this study, 20 dentists responded to the 11 questionnaires in which 5 point Likert-type scale was used. The two devices were operated for 10 seconds and measured 5 times to compare the maximum noise values. In heat emission test, the handpiece was operated for 3 minutes and heat was measured at three positions each. Results: TRAUS XUS10 had higher satisfaction level on motor noise (P < 0.05). About function key and handpiece heat generation, PIEZOSURGERY touch showed higher satisfaction (P < 0.05) than TRAUS XUS10. The maximum noise level for each of the devices was confirmed to be 56.6 dB for the TRAUS XUS10 and 56.0 dB for PIEZOSURGERY touch. The two piezoelectric engines satisfied the safety standards with an operation temperature below $41^{\circ}C$ after having been operated for 3 minutes. Conclusion: Except for the function key and handpiece heat emission, TRAUS XUS10 has comparable performance with PIEZOSURGERY touch.

• Journal of dental hygiene science
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• v.23 no.2
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• pp.176-184
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• 2023

Background: Recently, a piezoelectric ultrasonic scaler based on a feedback control mechanism was introduced for pain relief. This study aimed to investigate the effects of a new ultrasonic scaler in reducing pain and discomfort in adults. Methods: A newly introduced ultrasonic scaler (Master 700^®) was used as the test device and a conventional ultrasonic scaler device (PIEZON^®) was used as the control device. Forty-one healthy adults visited the dental clinic for dental scaling but did not undergo scaling or periodontal treatment within 6 months. Intraoral examinations were performed before scaling and 3 months later; before scaling, both devices were randomly assigned on the left or right side of each dentition (split-mouth model) and scaling was performed by a registered dental hygienist. The levels of pain and discomfort during scaling were evaluated subjectively and objectively using the visual analog scale (VAS) and physiological monitoring of the heart rate (HR), respectively. Time was measured for each device. Results: All clinical indicators, except bleeding on probing, significantly improved with both devices. The treatment times were 7 minutes, 13 minutes (control) and 6 minutes, 59 minutes (test). VAS scores for pain were 4.89±2.12 (control) and 4.58±2.77 (test) points out of 10; for noise, these were 4.68±2.33 (control) and 4.55±2.55 (test), and for vibration, the values were 4.26±2.0 (control) and 4.18±2.48 (test). HR averages were 72.34±3.39 (control) and 75.97±9.78 (test) beats/min. No statistically significant differences were observed between the devices. Conclusion:The pain, discomfort levels, and scaling time of the new piezoelectric ultrasonic scaler did not differ from those of the conventional device. Further research and development are necessary for more prominent pain-relief effects of scaling devices.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.3
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• pp.239-251
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• 2023

The aim of this study is to evaluate the effect of noise-filtering earplugs on the hearing ability of dentists wearing them during noise-induced dental procedures. Pure tone audiometry and distortion product otoacoustic emission (DPOAE) tests were conducted at the initial visit and 1 year later to evaluate the hearing ability of the participants. As a result of the study, the pure tone average of the group wearing earplugs decreased significantly compared to the group not wearing earplugs, indicating an improvement in hearing. However, the signal-to-noise ratio of the DPOAE tests did not show a significant difference. These findings suggest that noise-filtering earplugs may have some effectiveness in preventing hearing loss. However, since the 1-year observation period may not be adequate to identify changes in hearing, a follow-up study with an extended follow-up period is necessary.

• Imaging Science in Dentistry
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• v.40 no.3
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• pp.103-107
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• 2010

Purpose : This study was performed to examine the effects of image filter on observer performance by counting the number of holes at each wedge step on a radiographic image. Materials and Methods : An aluminum step wedge with 11 steps ranged in thickness from 1.5 mm to 16.5 mm in 1.5 mm increments was fabricated for this study. Each step had 10 notched holes with 1.0 mm diameter on the bottom of the step wedge which were ranged in depths from 0.1 mm to 1.0 mm in 0.1 mm increments. Digital radiographic raw images of the aluminum step wedge were acquired by using CCD intraoral sensor. The images were processed using several types of noise reduction filters and kernel sizes. Three observers counted the number of holes which could be discriminated on each step. The data were analyzed by ANOVA. Results : The number of holes at each step was decreased as the thickness of step was increased. The number of holes at each step on the raw images was significantly higher than that on the processed images. The number of holes was different according to the types and kernel sizes of the image filters. Conclusions : The types and kernel sizes of image filters on observer performance were important, therefore, they should be standardized for commercial digital imaging systems.

• Tribology and Lubricants
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• v.23 no.5
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• pp.240-247
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• 2007

The design process of the dental handpiece is described. The parameters of the high speed air turbine are estimated. The effect of supply hole on the stiffuess and damping of the air bearing for handpiece is studied numerically. The Reynolds equation is solved by using the divergence formulation and the perturbation method. The test rig is built and the test procedure is developed for the turbine rotational speed measurement by using Fourier transform of noise generated by the turbine during steady operation.