• The Journal of the Korean dental association
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• v.54 no.4
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• pp.258-273
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• 2016

In spite of appropriate treatment of peri-implantitis, the peri-implant bone loss was keep going, the clinician should remove the osseointegrated implant. the conventional methods are like a extraction of natural teeth, and use of trephine drills. In these days, many exclusive instruments are invented by implant companies. these instruments can make easy, least invasive, less traumatic removal of osseointegrated implants. In generally peri-implant bone loss progress steadily less sign and symptoms that the patient do not want to remove their implants. However, the failure of dental implant is big burden to clinicians and also patients. In the dental implant treatment, there is no 'failure' but only is 'replacement' or 'change'.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.38.1-38.10
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• 2020

Objectives: This study aimed to evaluate vital pulp tissue removal from different endodontic instrumentation systems from root canal apical third in vivo. Materials and Methods: Thirty mandibular molars were selected and randomly divided into 2 test groups and one control group. Inclusion criteria were a positive response to cold sensibility test, curvature angle between 10 and 20 degrees, and curvature radius lower than 10 mm. Root canals prepared with Hero 642 system (size 45/0.02) (n = 10) and Reciproc R40 (size 40/0.06) (n = 10) and control (n = 10) without instrumentation. Canals were irrigated only with saline solution during root canal preparation. The apical third was evaluated considering the touched/untouched perimeter and area to evaluate the efficacy of root canal wall debridement. Statistical analysis used t-test for comparisons. Results: Untouched root canal at cross-section perimeter, the Hero 642 system showed 41.44% ± 5.62% and Reciproc R40 58.67% ± 12.39% without contact with instruments. Regarding the untouched area, Hero 642 system showed 22.78% ± 6.42% and Reciproc R40 34.35% ± 8.52%. Neither instrument achieved complete cross-sectional root canal debridement. Hero 642 system rotary taper 0.02 instruments achieved significant greater wall contact perimeter and area compared to reciprocate the Reciproc R40 taper 0.06 instrument. Conclusions: Hero 642 achieved higher wall contact perimeter and area but, regardless of instrument size and taper, vital pulp during in vivo instrumentation is not entirely removed.

• Journal of dental hygiene science
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• v.22 no.2
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• pp.108-114
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• 2022

Background: Students in the department of dental hygiene are exposed to injections and sharp instruments during clinical practice. Therefore, it is necessary to develop measures for a safe practice environment. This study aimed to investigate dental stabbing accidents caused by dental instruments during clinical practice among students in the department of dental hygiene and suggest appropriate preventative measures. Methods: This study was conducted from May 1 to June 30, 2016, with students in the department of dental hygiene located at several universities in Seoul and Gyeonggi area. The study included 339 participants. A frequency analysis was performed to determine the general characteristics of dental infection control. A cross-analysis was conducted to identify the relationship between dental infection control education, stabbing accident prevention education, and treatment after stabbing accidents with a dental instrument. Results: Among the participants, 81.1% received dental infection control education and 66.4% received stabbing accident prevention education. Only 50.9% received hepatitis B vaccinations. Conclusion: Dental infection control education and stabbing accident prevention education were shown to be effective in preventing dental instrument stabbing in students. However, post-accident processing, such as reporting to upper management and medical treatment after the accident, was insufficient. Therefore, it is necessary to present a treatment flowchart for dealing with stab accidents in clinical practice for students in the department of dental hygiene and strengthen education.

• The Journal of the Korean dental association
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• v.19 no.2 s.141
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• pp.131-134
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• 1981

• The Journal of the Korean dental association
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• v.57 no.11
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• pp.672-678
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• 2019

AIM: The purpose of this study was to evaluate and compare the torsional fracture resistances, cyclic fatigue resistance, and bending stiffness of two nickel-titanium (NiTi) rotary instruments made of different heat-treated alloy: Aurum Blue (heat-treated) and Aurum Pro (conventional). Methods: Forty-five Aurum Blue and Aurum Pro NiTi files were selected for the three mechanical tests (n=15). For the torsional resistance test, 3 mm file tip was fixed and the shaft was driven clockwise at 2 rpm until fracture occurred by using a customized device. Cyclic fatigue resistance was evaluated by rotating instruments in artificial canal with dynamic mode. Bending stiffness was tested by observation of the bending moment on attaining a 45° bend. The results were analyzed by student-t tests at a significance level of 95%. The fractured surface of each groups were examined under a scanning electron microscope (SEM). Results: Aurum Blue showed significantly higher toughness, ultimate strength, distortion angle, and number of cycles to failure than those of Aurum Pro (p < 0.05). However, Aurum Blue and Aurum Pro did not differ significantly in terms of bending stiffness. SEM showed typical topographic appearances of the cyclic fatigue and torsional fracture. Conclusions: Under the limitations of this study, heat-treated instruments showed higher flexibility and fracture resistances than conventional NiTi instruments.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.187-195
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• 2021

In order to assess the cell toxicity of 10 instruments made of polymers, the MTT assay which utilizes the L-929 cell was selected. Specimens were eluted at a temperature of 37℃ for 24 hours at a rate of 4g per 20mL, RPMI 1640, and then was positively and negatively contrasted with a control test solution, in accordance with the Notification No. 2020-12 Protocols of Medical Apparatus Biological Safety from the Ministry of Drug and Food Safety. As a result of 24 hours of incubation in 37℃, 5% CO₂ Incubator and assessment using an ELISA reader, the results of Intraoral camera indiciated a cellular viability of more than 70% at a 50% eluate. But, the Plastic impression tray, 3D printing tweezer, Impression disposable syringe, Dental floss holder, Hand implant scaler, Surgical retractor, Oral scanner tip, Dental mirror, and the Water pick tip all reported a cellular viability of more than 70% at a 100% eluate, which indicates that do not exhibit cytotoxicity, thus allowing it to be used in contact with the mucous membrane of the oral cavity.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.14.1-14.7
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• 2020

Objective: The aim of this study was to perform a comparative evaluation of the effectiveness of ultrasonic tips versus the Terauchi file retrieval kit (TFRK) for the removal of broken endodontic instruments. Materials and Methods: A total of 80 extracted human first mandibular molars with moderate root canal curvature were selected. Following access cavity preparation canal patency was established with a size 10/15 K-file in the mesiobuccal canals of all teeth. The teeth were divided into 2 groups of 40 teeth each: the P group (ProUltra tips) and the T group (TFRK). Each group was further subdivided into 2 smaller groups of 20 teeth each according to whether ProTaper F1 rotary instruments were fractured in either the coronal third (C constituting the PC and TC groups) or the middle third (M constituting the PM and TM groups). Instrument retrieval was performed using either ProUltra tips or the TFRK. Results: The overall success rate at removing the separated instrument was 90% in group P and 95% in group T (p > 0.05) The mean time for instrument removal was higher with the ultrasonic tips than with the TFRK (p > 0.05). Conclusion: Both systems are acceptable clinical tools for instrument retrieval but the loop device in the TFRK requires slightly more dexterity than is needed for the ProUltra tips.

• The Journal of Korean Academic Society of Nursing Education
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• v.7 no.2
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• pp.229-244
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• 2001

The purposes of this study are to do surveys of the state of health and dental health behaviors of higher grade students in elementary school and their mothers, to investigate the relationship of students' dental health, and to apply those results to the systematic and efficient dental health care. The subjects were totally 618 people, including 309 elementary school students in 4th, 5th, or 6th grades and their mothers in Pusan. The questionnaires were used as instruments, which were made by the researcher and related with other preceeding studies. The content validity of the instruments was tested by two professors of nursing. Dental checking were conducted by an expert of dental sanitation, according to the standard of the World Health Organization. The period of collecting data was 20 months from October 20th to December 20th in 2000 and the collected data were analyzed by SAS program and classified as the real number, the percentage, the mean, the standard deviation, t-test, and F-test. In conclusion, there is no significant correlation between grades and treated or treatment-needed permanent teeth. There is the highest significant correlation between treated or treatment-needed permanent teeth and students' dental health behaviors. There is high significant correlation between mothers' dental health behaviors and students' dental health behaviors. Also, There is significant correlation between mothers' state of dental health and students' state of dental health. From the results of this study, the students' dental health behaviors are the most important variables in the students' state of dental health. But both boys(9.48) and girls(9.97) get the low marks on the total mark 15 about brushing, which can be self-controlled. Therefore, the developments of dental health guidance in education about dental health by mothers or the educational courses in schools, such as brushing educations by the experts, dental health education, brushing after lunch, or the various equipments in brushing, should be accomplished. Above all, behavior-centered education should be conducted instead of knowledge-centered education.

• Safety and Health at Work
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• v.2 no.4
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• pp.348-354
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• 2011

Objectives: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. Methods: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects' collar to record personal noise dose exposure during working periods. Results: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ${\pm}$ 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. Conclusion: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.3
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• pp.204-211
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• 2017

In dentistry, elevator instruments are used to luxate teeth, and this technique imparts forces to tooth particles that sever the periodontal ligament around tooth roots inside the socket and expand alveolar bone around tooth particles. These effects can result in extraction of the tooth particles or facilitate systematic forceps extraction of the tooth particles. This article presents basic oral surgery techniques for applying elevators to luxate teeth. Determination of the optimal luxation technique requires understanding of the functions of the straight elevator and the Cryer elevator, the concept of purchase points, how the design elements of elevator working ends and tips influence the functionality of an elevator, application of forces to tooth particles, sectioning teeth at furcations, and bone removal to facilitate luxation. The effectiveness of tooth particle luxation is influenced by elevator tip shape and size, the magnitude and the vectors of forces applied to the tooth particle by the tip, and sectioning and bone removal within the operating field. Controlled extraction procedures are facilitated by a dental operating microscope or the magnification of binocular surgical loupes telescopes, combined with co-axial illumination.