Effects of acidic electrolyzed water, alkaline water and their mixed water to

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 17592050
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 補綴理工系歯学
• Research Institution: The Nippon Dental University
• Principal Investigator: AOKI Harumi The Nippon Dental University, School of Life Dentistry at Tokyo, Associate Professor, 生命歯学部, 助教授 (50150925)
• Project Period (FY): 2005 – 2006
• Keywords: acidic electrolyzed water / alkaline electrolyzed water / mixed water / natural human teeth / dental alloy / Color difference / weight change / pH

Research Abstract

We investigated effects of acidic electrolyzed water(about pH3), alkaline electrolyzed water(about pH12) and their mixed water(pH5.00 and pH7.00) to natural human teeth and dental alloys.
1. Natural human teeth : Color of enamel surface immersed in acidic electrolyzed water turned white even after one hour. As term immersed in acidic electrolyzed water, this change became severe. Color differences of enamel surface which were immersed in acidic electrolyzed water was 7.0(NBS unit). Rate of weight change of human teeth immersed in mixed water was lower than immersed in acidic electrolyzed water. On longitudinal grinding section of sample immersed in acidic electrolyzed water up to six hours, we could investigate thinner translucent layer at the most surface area. Translucent layer became thicker as immersion period longer. On contact microradiograph, these layers were observed X-ray transmitted layers. By electron micro-probe analysis, Ca, P, Mg concentrations of this layer ware obviousl y decreased.
2. Dental alloys : Color differences of dental alloys which were immersed in acidic electrolyzed water were highest-16.6, and pH5.00-11.5, pH7.00-10.3, pH12-3.0. As pH value was increased, alloy color became lighter except one of silver alloy. The color of this sample immersed in acidic electrolyzed water turned white, and color difference was lowest-12.5. As pH value was increased, that color changed black. Color difference when immersed into pH7.00 was 26.4. Rate of weight change of alloys immersed in mixed water was lower than those immersed in acidic electrolyzed water. Especially, rate of weight change gold alloys immersed in acidic electrolyzed water was very high, that was -0.03〜-0.09%. Rate of weight change of all alloys by static immersion test was higher than that of dynamic immersion test.
As above, when we treat acidic electrolyzed water into our oral as gargling agent, pH should be controlled in order to avoid teeth decalcification and discoloration of dental alloys.