| Dental impressions, whose surface may carry a great number of bacteria, viruses and other pathogenic microorganisms because of getting in touch with patient's saliva or blood in making process, are liable to cause cross- infection among dentists, patients and dental technicians. For alginate impression materials which are widely used in stomatology hospital of China, the current disinfecting methods include immersion or spraying with disinfectants. However, immersing disinfection could make adverse impact on the accuracy of impression and damage the detail of alginate impression surface. Furthermore, the volatilization of disinfectants would do potentially harm on human body.To avoid adverse affect caused by disinfecting methods above, some scholars try to make out a kind of self-disinfecting impression materials by impregnating the antimicrobial agents into dental alginate impression material. However, the decomposition of the organic antibacterial agents, which are mostly impregnated into alginate impression material, is generally toxic. One clinical investigation has proved that the alginate impression material impregnated with quaternary ammonium compounds could produce oral mucosa irritation and allergic reaction, which seriously violates the people's medical requirements of safety and standardization. Therefore, it becomes one hospot that scholars try to obtain active substances from natural resources instead of chemical drugs. The aim of this paper is to investigate the anti- bacterial activities of alginate impression materials impregnated with bamboo extract, to evaluate its impact on the physics properties and dimensional stability, which provides experimental evidence to development of self- disinfecting alginate impression materials, as well as better exploitation of bamboos in China.Content and methods:1.The objective of this study was to investigate the antibacterial activities of the extracts from P. pubescens and P. amaru by Agar dilution method for antimicrobial susceptibility test.2.The extracts from two bamboo extract were respectively impregnated into the alginate impression materials in the proportions of 0.5%,1%,1.5%,2%.The antibacterial abilities for Staphylococus aureus ATCC25923,Escherichia coli ATCC259 and Streptococcus mutans ATCC25175 were measured using a method , which accords to the Chinese and Japanese standards for testing antibacterial activities of antibacterial materials.3. The relevant physics properties of impressions impregnated with bamb- oo extract, such as setting time, flowability, deformation and strength were te- sted respectively.4. The study was to measured the influence of bamboo extract on the impressions'dimensional stability, as well as comparing to the control group and the impressions that had been immersed in glutaraldehyde for disinfectionThe results are as follows:1. The minimal inhibitory concentration(MIC) of the extracts from P. pubescens was 3.125mg/ml against S. aureus and 6.25mg/ml against both E. coli and S. mutans;The MIC of the extracts from P. amarus was 3.125mg/ml against S. aureus,and 6.25mg/ml against E. coli,and 12.5mg/ml against S. mutans.2. The antibiosis ratios of the alginate impression materials impregnated with P. pubescens in the proportion of 1.5% or P. amarus in the proportion of 2% against three tested bacteria strains were all over 99%. It can be preliminary concluded that the impressions impregnated with bamboo extract have strong antibacterial activity and the antibacterial ability of P. pubescens is better than P. amarus's.3. The experimental datas showed that there was no significant deviation on the physics properties between the impressions impregnated with bamboo extract and the control group(p>0.05), the datas are both within the normal scope formulated by the Chinese and ADA standards.4. There was no significant deviation on the dimensional stability between the impressions impregnated with bamboo extract and the control group (p>0.05), and the dimensional stability of the self-disinfecting impressions is superior to the impressions that had been immersed in glutaraldehyde for disinfection.Conclusions:It can be preliminary concluded that the alginate impression materials impregnated with P. pubescens in the proportion of 1.5% or P. amarus in the proportion of 2% have excellent antibacterial activity, and the impregnation of the extract of two bamboos has no significant influence on the physics proper- ties and dimensional stability. |
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