Sterilization Effect of Wet Oxygen Plasma in the Bubbling Method.

A new low-temperature sterilization method to replace the ethylene oxide gas sterilization is needed. Strong bactericidal effects of OH and O2H radicals are well known. The purpose of this study was to evaluate the sterilization effect of wet oxygen ("O2+H2O") plasma in the bubbling method, confirming the effect of humidity. Sterility assurance was confirmed by using a biological indicator (Geobacillus stearothermophilus ATCC7953, Namsa, USA). One hundred and eight samples (10(5) spores/carrier) were divided into three groups of 36 in each for treatment with a different type of gas (O2, O2+H2O, Air+H2O). Plasma processing was conducted using a plasma ashing apparatus (13.56 MHz, PACK-3(®), Y. A. C., Japan) under various gas pressures (13, 25, 50 Pa) and gas flows (50, 100, 200 sccm). Fixed plasma treatment parameters were power at 150 W, temperature of 60 ℃, treatment time of 10 min. The samples after treatment were incubated in trypticase soy broth at 58 ℃ for 72 h. The negative culture rate in the "O2+H2O" group was significantly (Mantel-Haenszel procedure, p<0.001) higher than in the other gas groups. It is suggested that the significant sterilization effect of the "O2+H2O" group depends on the bubbling method which is the method of introducing vapor into the chamber. The bubbling method seems able to generate OH and O2H radicals in a stable way.

[Planning guidelines for prosthodontic treatment].

In recent years "practice guidelines" based on EBM techniques have even been attracting attention at a societal level, and guidelines modeled after the procedure for preparing practice guideline (described at http://www.niph.go.jp/glgl-4.3rev.htm) have begun to be drafted and made public. With the aim of ensuring the quality and presenting the basic concepts of prosthodontic therapy, the Japan Prosthodontic Society, which bears a great obligation and responsibility toward society and the Japanese public, has decided to undertake the formulation of guidelines related to prosthodontic therapy, and decided to first undertake the formulation of "Practice guideline for denture relining and rebasing", and to prepare a guideline model. We tried to prepare the guidelines according to the "Procedure for preparing practice guidelines", but because of the scientific uniqueness of prosthodontic treatment and dentistry, research to elucidate the basis of treatment has been insufficient, and we ultimately reconfirmed the current state of affairs in which it is difficult to perform. We therefore prepared the guidelines based on the limited evidence obtained in a search of the scientific literature and on the consensus of experts. The Japan Prosthodontic Society has investigated and prepared a Society guideline "model" to the extent possible at the present time, and it has prepared "Guidelines for adhesion bridge" and "Practice guidelines for denture prosthodontics" based on it. Nevertheless, the fact of the matter is that we are faced with numerous problems, and we think that in the future new bases and clinical knowledge will be accumulated by promoting scientific clinical research, and that the guidelines should be revised regularly based on them.

A new dental unit for both patients in wheelchairs and general patients.

OBJECTIVE: To develop a dental unit to accommodate both patients in wheelchairs and general patients, and to evaluate the acceptability of the new chair for patients and dentists. DESIGN: To integrate a unit for patients in wheelchairs and a unit for general patients into a single dental unit. RESULTS: (1) The newly developed dental unit could be used for both patients in wheelchairs and general patients and could be installed in nearly the same space as occupied by a conventional dental unit. (2) The dentists could take the home position because of the height-adjusting and tilting mechanisms. (3) The patients could be treated with a sense of assurance because of the wheelchair immobilizer and the safety devices. (4) The dentists could perform patient treatment safely. (5) As patients did not need to be transferred from their wheelchairs, assistance was unnecessary. (6) From the questionnaires, both patients and dentists rated the newly developed dental unit favourable. CONCLUSIONS: The new dental unit for patients in wheelchairs and general patients permitted dentists to perform and patients to receive dental treatment safely and in a comfortable position. Also, as a single unit could be used for treatment of both types of patients, it required no extra space. Therefore, it has the potential to be installed in the clinics of general dental practitioners to treat both groups of patients.