• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.990-995
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• 2012

A piezoelectric ultrasonic bone surgical instrument, usually used to remove the tartar out of teeth or to cut the dentine of the tooth, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power and precision control of surgical operation. It has typically two parts of a tip and vibration system which is also composed of head, piezoelectric elements and tail-mass. In order to improve the performance of the instrument, it is important to standardize the size of the vibration system without tip for high performance. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic instrument in vibration system. Consequently, this study revealed that influence of several tips on property were minimized and it showed good property at the frequency range of 22~32 kHz.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.154-154
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• 2017

Ti-6Al-4V alloys are widely used as metal-lic biomaterials in dentistry and orthopedics due to its excellent biocompatibility and me-chanical properties. However, because of low biological activity, it is difficult to form bone growth directly on the surface of titanium implants. For this reason, surface treatment of plasma electrolytic oxidation(PEO) was used for dental implants. To enhance bioac-tivity on the surface, strontium(Sr) and sili-con(Si) ions can be added to PEO treated sur-face in the electrolyte containing these ions. The presence of Sr in the coating enhances osteoblast activity and differentiation, where-as it inhibits osteoclast production and prolif-eration. And Si has been found to be essen-tial for normal bone, cartilage growth, and development. In this study, electrochemical characteristics of Ca, P, Sr, and Si ions from PEO-treated Ti-6Al-4V alloy surface was re-searched using various experimental instruments. DC power is used and Ti-6Al-4V al-loy was subjected to a voltage of 280 V for 3 minutes in the electrolyte containing 5, 10, 20M% Sr ion and 5M% Si ion. The morphol-ogies of PEO-treated Ti-6Al-4V alloy by electrochemical anodization were examined by field-emission scanning electron micro-scopes (FE-SEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) and corrosion analysis using AC impedance and potentiodynamic polarization test in 0.9% NaCl solution at similar body tempera-ture using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV.

• Corrosion Science and Technology
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• v.9 no.5
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• pp.223-232
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• 2010

NiTi alloy has been used for orthodontic wire due to good mechanical properties, such as elastic strength, friction resistance, and high corrosion resistance. Recently, these wire were coated by polymer and ceramic materials for aesthetics. The purpose of this study was to investigate electrochemical characteristics of tooth colored NiTi wire using various instruments. Wires (round type and rectangular type) were used, respectively, for experiment. Polymer coating was carried out for wire. Specimen was investigated with optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS). The corrosion properties of the specimens were examined using potentiodynamic tests (potential range of -1500 ~ 2000 mV) and electrochemical impedance spectroscopy (frequency range of 100 kHz ~ 10 mHz) in a 0.9 % NaCl solution by potentiostat. From the results of polarization behavior, the passive region of non-coated NiTi wire showed largely, whereas, the passive region of curved NiTi wire showed shortly in anodic polarization curve. In the case of coated NiTi wire, pitting and crevice corrosion occurred severely at interface between non-coated and coated region. From the results of EIS, polarization resistance(Rp) value of non-coated round and rectangular NiTi wire at curved part showed $5.10{\times}10^5{\Omega}cm^2$ and $4.43{\times}10^5{\Omega}cm^2$. lower than that of coated NiTi wire. $R_p$ of coated round and rectangular NiTi wire at curved part showed $1.31{\times}10^6{\Omega}cm^2$ and $1.19{\times}10^6{\Omega}cm^2$.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.137-147
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• 2007

Dentists are known to be highly exposed to the musculoskeletal disorders (MSD). The present study investigated the prevalence of MSD among Korean dentists and association between their MSD and physical workload. In addition, work-related causes of high physical workload were identified and needs of dentists were collected for improvement of dental instrument and environment. Four types of questionnaires including the Nordic questionnaire were used to investigate body troubles, physical workload, causes of physical workload, and improvement priority of dental components. A total of 104 dentists in Seoul were participated in the survey. Neck trouble (82%) was the most prevalent in the participated dentists and shoulder (68%) and low back trouble (56%) followed, while low back trouble was reported to be most common in previous western studies. The body troubles were related to the physical workload of the corresponding body parts, although they were not associated with personal characteristics. Most dentists selected 'to keep direct view inside patient's mouth' and 'no support of the hand with dental instruments' as causes of awkward and strenuous work postures. They wanted design improvement for some components in their operating room such as operating light and arrangement of workplace.

• Journal of dental hygiene science
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• v.5 no.2
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• pp.45-49
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• 2005

This study is designed to present basic materials necessary for offering the more effective way of dental hygienists, or those who are in charge of the education of Oral health, the treatment and prevention of dental problems, educating Oral health by stage by dint of determining the actual condition of the knowledge and management of dental hygiene, or prevention of the basic dental disease except the professional methods of dental management and evaluating their abilities to manage dental hygienes. In terms of the real conditions of the management of dental hygienes, the majority of the subjects said, "not bad" or "healthy". Most of them (62.1%) said that they brush their teeth three times a day, and most of them (85.2%) depend on rolling methods. 69.2% of them used brushes that are neither hard nor soft, and 28.4% of them use soft brushes and 49.7% of them brush their teeth for about 3 minutes. In terms of brushing time, 27.8% of them brush their teeth after lunch, while 23.8% of them brush their teeth after breakfast. 66.3% of them use fluoric tooth pastes while 19.5 percent of them said, "I have no idea." and 14.2% of them said, "No." In terms of complementary dental hygiene goods, dental goggles are used by 23% of them, and dental threads are used by 78.1% and tooth brushes are used by 78.1% of them, and 42.4% of the subjects use the instruments one to twice a day, and 53.8% of them use them for less than one minute a time. In terms of dental health care, 17.2% of them have a chew of gum and 8.3% of them pay a regular visit to dental clinics and 5.3% of them don't smoke.

• Journal of dental hygiene science
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• v.14 no.1
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• pp.59-66
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• 2014

The purpose of this study was to study of utilization of dental high school and according to the pain experienced dental fear and anxiety. This survey was conducted on 370 high school students in Suwon from November 21 to 23, 2011. A total of 352 questionnaires were collected and analyzed. The collected data was analyzed using the statistical package SPSS 15.0 using frequency, mean and standard deviation analysis, t-test, one-way ANOVA, Duncan's test correlation analysis and Stepwise multiple regression analysis. The results state that students feel fear and anxiety were feeling anesthetic needle ($3.19{\pm}1.43$), seeing anesthetic needle ($3.14{\pm}1.44$). We found that students feel more rear and anxiety from caries treatment than scaling. It influence that having dental fear with past dental pain experienced during dental treatment and also hearing dental treatment of pain from their family and friends. We found out that there are some influencing factors on dental fear and anxiety, gender, oral health condition, smoking, pain experienced during dental treatment. We need to care dental fear and anxiety continuously and have prevention program. We have to try understanding students have dental fear and anxiety. So it's better they have good experience visiting dental clinic. We should develop the system and specially treat well while they have dental treatment with anesthesia and some sharp instruments.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.3 no.2
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• pp.97-100
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• 2007

In patients with cerebral palsy, dental treatments, which require absolute patient's corporation, have many difficulties because of muscle spacity, involuntary muscle movements and spasm. Especially in endodontic treatments which very meticulous instrumentation is needed, these muscle discordances may lead to unexpected accidents such as tissue damage while filing, over-instrumentation and swallowing instruments. Also, taking radiographs for measuring canal length is often hindered by walking and movement disorders. This paper is to present a clinical case of one-visit root canal treatment using electrical apex locator under general anesthesia in a cerebral palsy patient.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.611-612
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• 2003

Mechanical removal in decayed teeth has been performed using drill and sharp hand instruments. These methods have some major disadvantages. Namely mechanical preparation often induces pain, local anesthesia and often leads to overextended cavities. Therefore, to avoid these difficulties, a possible alternative method has been introduced for chemo-mechanical excavation of dentin caries lesions on the market. The purpose of this study was to evaluate the efficacy of between traditional mechanical and chemo-mechanical methods(Carisolv).(omitted)

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.4
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• pp.763-770
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• 1997

The air abrasive technique is a non-mechanical method by which teeth are treated before restoration and stains and calculi are removed from tooth surfaces using the kinetic energy of small particles. The air abrasive technique in dentistry was first introduced in the 1950's with as instrument called 'Airdent'. But, as the main restorative materials of the period were amalgam and gold, and the instrument's inability to control the flow of particles caused the particles to be spread throughout the clinics, widespread use was not possible. In the 1990's, as these techincal problems were solved and more interest in new restorative materials rose in an effort to preserve sound tooth structure, new developements took place in instruments related to the air abrasive technique. The air abrasive technique produces less pressure, vibration and heat that might cause patient discomfort and facilitates the preservation of sound tooth structure. It also reduces the need for anesthesia and is less harmful to the pulp. Other advantages include increase in dentin bonding strength of composite resin, lower possibility of saliva contamination and maintenance of a dry field. But there is not direct contact between the nozzle and the tooth, the operator cannot use his or her tactile sense and must rely solely upon visual input. Other disadvantages are: the tooth preparation depends on the operator's ability; alpha-alumina particles, after bouncing off the tooth surface, cause damage to dental mirrors; the equipment is expensive and takes up a certain amount of space in the clinic. The author conducted case report using the air abrasive technique on patient visiting the Department of Pediatric Dentistry at Seoul National University Dental Hospital and arrived at the following conclusions. 1. The tooth preparation capability of different air abrasive devices varied widely among manufacturers. 2. It was more effective in treating early caries lesions and stains compared to lesions where caries had already progressed to produce soft dentin. 3. The cold stream and noise caused by the evacuation system was a major cause of discomfort to pediatric patients. 4. As there is no direct contact with tooth surface when using the air abrasive technique for tooth preparation, considerable experience and skill is required for proper tooth preparation.

• Journal of Korean Academy of Dental Administration
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• v.5 no.1
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• pp.13-21
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• 2017

Objective: To understand the experience of medical accidents and disputes according to clinical career of dental hygienists. Methods: A self-administrated questionnaire survey was conducted from May 2012 to June 2012 targeting 313 dental hygienists in Gyeongsangnam-do, Republic of Korea. Data were analyzed by descriptive analysis, χ2-test, and one-way analysis of variance (ANOVA). Collected data were analyzed using SPSS 18.0. Results: 1) The group who had more than 6 years of clinical experience experienced complaints from patients (70.3%) and dental hygienists duty (30.7%); 2) Complaints were related to diagnosis, dental treatment instruments and materials, scaling, impression preparation, and prosthodontics. Pediatric patients had significantly more complaints compared to other patients. Overall, there were more frequent cases in the group with over 6 years of clinical career; 3) For the psychological state after experiencing patients' complaints, 'the process is difficult, but I forget after thinking it could be happen' had 160 respondents. Among them, 38.1% had clinical experience of more than 6 years, 37.5% had less than 3 years, and 24.4% had clinical career of 3~6 years; 4) About 73.6% of those had 3~6 years of clinical career answered that 'sometimes it is doubtful' on the issue of medical accidents and conflicts on prevention education of dental hygienists that 'there is a doubt about the issue of medical treatment or the occurrence of disputes'. About 60.0% of those who had less than 3 years of clinical experience answered that it was highly 'necessary but not urgent' on the necessity of preventive education, while 87.1% of those who had more than 6 years of clinical career answered that it was highly 'necessary but not urgent' on the necessity of preventive education. The difference between the two was not statistically significant. Conclusions: It is necessary and urgent to provide education related to prevention and countermeasures against malpractice disputes for dental hygienists.