The purpose of this study is to assess airborne contamination of the dental operating room (DOR) in order to evaluate the risk of infection for the patients and dental staff. To examine DOR, a total of 744 air samples (0.01 Cubic Feet) collected in the particle counter hourly in 24 times a day for 31 days was used. Further, we investigated the change in the particle during tooth preparation (TP) with a highspeed hand-piece when using or not suction device.
The results were as follows:
1) In almost all time from 9:00 to 17:00, the number of 1.0μm, 2.0μm and 5.0μm particles in the treatment days (20 days), were significantly (Welch’s t-test, p<0.05) greater than the closing office day (11 days).
2) The particle of 0.3μm, 0.5μm, 1.0μm, 2.0μm and 5.0μm during TP as compared to before TP, increased by 7.5 times, 50.0 times, 158.9 times, 144.6 times and 47.7 times, respectively. When using the intra-oral suction(IOS), these particles were remarkably reduced. When using the IOS and the extra-oral suction (EOS), 2.0μm and 5.0μm particles were further reduced to the level before TP, and were significantly (paired t-test, p<0.05) reduced compared to IOS alone.

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A pressurized metered dose inhaler (pMDI) has been used in treatment of obstructive airway diseases such as bronchial asthma. In the treatment, the pressing timing of a button on the pMDI to spray the medication should be synchronized to the timing of inspiration, in order to maximize the therapeutic effect. At present, the timing coordination of hand with inspiration is instructed to the patients by medical staffs; however, the technique may not easily acquired, and may result in insufficient therapeutic effect. For this issue, an inhalation aid such as the Spacer is already supplied, but the preparation and cleaning up after the treatment is troublesome. We have developed an aidingsystem for the pMDI. In this system, a button switch and an airflow sensor are attached to the pMDI, and a microcomputer records the pressing button time and the inspiration airflow. The system provides the medical staff quantitative information of the treatment, and promotes patient education including treatment frequency.

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The purpose of this study is to investigate the standardization of infection control methods during dental implant placement surgery.
We examined the contamination of the blood and body fluids scattered on personal protective equipment (PPE) which was worn by an assistant during surgery. Organic matter that was attached to face-shields and gowns was wiped with a cotton swab and detected using Coomassie Brilliant Blue for determination of protein.
Further we examined the effect of the cleaning process for reusable implant drills by using the Adenosine Triphosphate (ATP) bioluminescent method.
As the result, organic matter was detected from the sleeves and abdomen areas as well as the chest of the gowns. In addition organic matter was also detected from the all face-shields used in additional advanced surgery for bone augmentation. ATP value was significantly (P<0.05, paired t-test) less in the drills which were washed in both ultrasonic cleaner (US) and washer-disinfector (WD) than that in the US only.
In conclusion, the assistant as well as the operator should wear PPE such as the long gown with long sleeves and the face-shield to protect from infections during surgery. Further, in the use drills, single use is desirable, because a very small amount of ATP was detected in the drills cleaned by both UC and WD.

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The purpose of this study is to achieve zero wear of UHMWPE by maintaining a good lubricating film to the artificial joint sliding surface between the femoral head and the socket components.
In order to keep the fluid film lubrication constantly between the sliding components, the processing technology of the femoral ball with the high sphericity can be required. So, the precision machining technique by the Die-Sinking EDM (Electric Discharge Machinery) and the spherical grinding machine was developed to improve the femoral head sphericity.
The main results obtained are as follows:
1) The sphericity of the femoral head has been improved by the EDM and the ball grinding machines, and the sphericity of 0.75μm was achieved to processing of the Ti-13Zr-13Nb femoral head ball.
2) The sphericity of the socket was 8.73μm, and by being used together with the femoral ball mentioned above, we could add the ability to keep the fluid film lubrication to the artificial hip joints.

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As previously reported, we developed an ultra-low friction Total Hip Arthroplasty Components consists of a Ti-13Zr-13Nb femoral head with high sphericity and a UHMWPE acetabular socket. For these components, we evaluated the ability to maintain the lubricating film by using an artificial hip joint simulator and a detaching testing system of the femoral head from the acetabulum.
As the results, the filloeing facts became clear.
1) The lubricating film was well maintained by radial clearance 13μm or less in the combination of PE acetabulum and metal head with the spericity of 8μm and 0.75μm, respectively.
2) If a good lubricating film is maintained in artificial joint sliding surface, the torque generated by the walking exercise fell to 1/100 of dry friction. Then, a good lubricating ability is kept at walking period 40rpm or more.

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We have reported the qualification result of Adenosine Tri-phosphate (ATP) extraction as an alternative cleaning process assessment method described in Guideline for Sterilization Assurance in Clinical Setting published by Japanese Society of Medical Instrumentation (JSMI) in 2010 at JSMI Annual Conference 2012. This study result indicated the possibility of that ATP extraction method is practical in clinical setting and can be an alternate to protein mass measurement because of the evaluation result regarding the correlation study result between ATP and protein measurements. In this article, additional study result of cleaning process assessment is reported using clinically-used surgical instruments and artificial soil devices at clinical site. ATP extraction and conventional ATP swabbing as well as protein extraction was performed after two different cleaning processes to evaluate the effectiveness of these cleaning processes for determining which cleaning process to take. It is observed that ATP swabbing is not appropriate for surgical instrument having such narrow lumen and/or space where swab cannot access to, because high ATP value was detected by extraction method from a surgical instrument after sampling with swab for ATP measurement. ATP measurement result from standardized artificial soil devices after one cleaning process was from 66 to 478 relative light unit (RLU) while ATP measurement result after another cleaning process was from 30 to 73 RLU (p value = 0.025). However, such statistical analysis was not achieved for protein measurement as detected protein level was under limitation for all protein measurements. ATP extract method is practical cleaning process assessment method at clinical setting, and this method has quantitative capability as well as excellent sensitivity compared to protein measurement method. In addition to these advantages, this extraction method can be applied to more devices which have physically-complex design and lumen devices compared to conventional swabbing method.

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