• Transactions of Materials Processing
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• v.16 no.1 s.91
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• pp.61-66
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• 2007

Powder injection molding(PIM) is widely used for many parts in the field of automotives, electronics and medical industries, due to the capability of net shaping for complex 3-D geometry. Powder injection mold design for the dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip which has complex geometry. Both product design and mold design for dental scaler tip were presented. A PIM feedstock was made of stainless series(17-4PH, 316L, 440C) powder and a wax based binder. The 'rapid mold' concept was applied to manufacture the various forms and materials of dental scaler tip including vibration characteristics.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.270-274
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• 2005

The capability of net shaping for complex 3-D geometry, powder injection molding(PIM) is widely used for parts in the field of automotives, electronics and medical industry. Powder injection mold design for dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip. Product design and mold design for dental scaler tip was presented. Short shot experiment with scaler tip PIM mold and several defect (flash etc.) during injection molding process was discussed.

• Transactions of Materials Processing
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• v.14 no.6 s.78
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• pp.570-576
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• 2005

Powder Injection Molding(PIM) has recently been recognized as an advanced manufacturing technology for low-cost mass production of metal or ceramic parts of complicated geometry With this regards, design technology of dental scaler tip PIM mold, which has complex shape and small core pin (diameter=0.6mm), with the help of computer-aided analysis of powder injection molding process was developed. Computer-aided analysis for dental scaler tip mold was implemented by finite element method with non-Newtonian fluid, modified Cross model viscosity, PvT data of powder/binder mixture. Compter-aided analysis results, such as filling pattern, weldline formation, air vent position prediction were compared with experimental result, and eventually have been shown good agreement. The core pin (diameter=0.6mm) deflection analysis of dental scaler tip PIM mold during PIM filling process was also investigated before mold fabrication.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.343-344
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• 2006

Powder injection molding(PIM) is widely used for many parts in the field of automotives, electronics and medical industries, due to the capability of net shaping for complex 3-D geometry. Powder injection mold design fur the dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip which has complex geometry. Both product design and mold design for dental scaler tip were presented. The 'rapid mold' concept was applied to manufacture the various forms of dental scaler tip.

• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.635-641
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• 2016

Objectives: The purpose of this study is to assess the characteristics of tooth surface after using Gracy curet and Ultrasonic scaler Methods: In this study, 12 teeth extracted were used. 12 specimens were divided into three groups with the same numbers, which were classified into Control group, Gracy curet use group, and Ultrasonic scaler use group, and after performing instrument operation, we measured the roughness and the loss degree of tooth surface by using SEM. Results: In groups using Gracy curet and Ultrasonic scaler, the roughness and the loss of tooth surface increased significantly(p<0.05). In the roughness of groups using Gracy curet and Ultrasonic scaler, Ultrasonic scaler group was higher in crown, but Gracy curet group was higher in root. As a result of observation through SEM, the roughness and the loss degree increased in order of Control group, Ultrasonic scaler use group, and Gracy curet use group. Conclusions: Taken together above results, both hand instrument and ultrasound equipment create roughness and loss in crown and in root, and hand instruments makes rougher than ultrasonic instruments in root, so it is thought to require thorough and accurate technical application not to damage tooth surface when removing plaque.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.83-84
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• 2006

Due to the capability of net shaping for complex 3D geometry, powder injection molding (PIM) is widely used for automotive parts, electronics and medical industry. In this study, an ultrasonic dental scaler tip produced by machining process was redesigned for the PIM process. An injection mold was designed and manufactured to produce the dental scaler tip by the PIM process.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.499-500
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• 2006

With the capability of net shaping for complex 3D geometry, powder injection molding (PIM) is widely used for automotive parts, electronics and medical industry. In this study, an ultrasonic dental scaler tip produced by machining process was redesigned for the PIM process. An injection mold was designed and machined to produce the dental scaler tip by the PIM process.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.64-80
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• 1998

The risk of cross-contamination in dental clinic is very high. Those who are engaged in dental clinic are exposed to various microorganisms in saliva and blood of patient. Potential possibility of cross-contamination of patient to patient, patient to dentist, dentist to laboratory technician always exist, which is important in the view of public health. It is well known that microorganisms may cause cross-contamination by suck-back of microorganisms into the water supply line or air supply line of dental unit and sprayed back into the next patient's oral cavity. The majority of microorganisms coming from dental unit are water microorganisms from the main water supply which have colonized the tube within the units and multiplied in the relatively warm and stagnant conditions. The purpose of this study is to measure the extent of microbial contamination of dental unit and ultrasonic scaler, to evaluate that dental unit water supply is suitable for drinking water, and to assess the effect of flushing on reduction of microbial contamination of dental unit and ultrasonic scaler. In the first experiment, water samples(50ml) from 20 dental units and 10 ultrasonic scalers in Seoul National Univ. Hosp. were tested for the presence of coliform. The samples were filtered by membrane filtration technique.(Microfil system, Millipore Co. U. S. A.) The filter was then placed onto MacConkey agar plate and the plates with filter on it were incubated aerobically at $37^{\circ}C$ for 5 days. The colors and shapes of colonies were examined if those were coliform. To verify the presence of coliform, the colonies were inoculated into phenol red lactose broth and incubated aerobically at $37^{\circ}C$ for 2 days. The fomation of gas was observed. In the second experiment, water samples from 20 handpieces, 10 ultrasonic scalers and 30 A/W syringes after 0, 2, 4, 6 min. flushing respectively were taken. $200{\mu}l$ water samples were spreaded on Brain Heart Infusion agar plate and the plates were incubated aerobically at $37^{\circ}C$ for 5 days. The number of colony was counted. The results obtained were summarized as follows 1. The water from dental unit and ultrasonic scaler was not suitable for drinking water. 2. No coliform was founded in dental unit and ultrasonic scaler water supply. 3. The number of colony of dental unit and ultrasonic scaler was highest in the group of o min. flushing(p<0.05). 4. There was no statistically significant difference in the extent of microbial contamination among handpiece, ultrasonic scaler and A/W syringe (p>0.05). 5. The number of colony was lowest in the group of 4 min. flushing, but there was no statistically significant difference among 2, 4, 6 min. flushing groups.(p>0.05) 6. It is recommended to flush dental unit water line for 4 min. after use on each patient.

• Journal of Korean society of Dental Hygiene
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• v.15 no.4
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• pp.713-718
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• 2015

Objectives: The purpose of the study was to investigate the bacterial morphology attached on ultrasonic scaler tips using no cleansing solution, alcohol cotton, liquid chemical disinfecting agent, and autoclave method. Methods: Scaling tip was applied to the mouth and the ultrasonic scaler tips were assigned to four groups. Group 1 was control group with no cleansing solution. Group 2 was treated with alcohol cotton. Group 3 was treated with 2% green Y-Na solution in liquid chemical disinfecting agent, and Group 4 was sterilized by autoclave method. Live bacteria were observed by phase contrast microscopy. The scanning electron microscopy(SEM) revealed the morphological characteristics of scaler surface. The type of attached bacteria were analyzed using SPSS 21.0 program. The data were analyzed by one-way analysis of variance(ANOVA) and Tukey's post-hoc test. Results: The types of sterilization methods had influences on the bacterial viability. The numbers of cocci, bacilli, spiral form bacteria, and filamentous bacteria was observed in $89.00{\pm}3.60%$, $29.67{\pm}3.51%$, $3.33{\pm}0.57%$ and $1.67{\pm}0.57%$ in control group, $31.67{\pm}3.51%$, $63.33{\pm}4.04%$, $2.00{\pm}1.00%$ and $1.67{\pm}0.57%$ in alcohol cotton group, $69.67{\pm}4.50%$, $12.33{\pm}2.51%$, 0% and 0% in liquid chemical disinfecting agent group, and 0.0%, 0.0%, 0.0% and 0.0% in autoclave method group. The clean surface of ultrasonic scaler tip was shown on SEM by autoclave method. Conclusions: The most effective sterilization method of ultrasonic scaler tip was the autoclave method. Autoclave method is the most effective sterilization method and can reduce the cross-infection in the dental clinic.