【作者】 刘强；

【导师】 钟才高； 李建群；

【作者基本信息】 中南大学 ， 公共卫生， 2012， 硕士

【摘要】 目的钴铬合金(Co-Cr alloy)因其优良的机械性能、良好的生物相容性、价格合理一直是重要的口腔修复材料,广泛应用于口腔临床修复。钴铬合金铸造支架可摘局部义齿及全冠戴入口腔后,释放出钴、铬等重金属离子能被机体吸收,形成对局部和全身组织的影响。近来,人们日益关注钴铬合金临床应用的安全性问题。钻铬合金应用于口腔临床修复时,释放出的铬离子的量的多少及其影响因素是首要解决的问题。钴铬合金在口腔修复应用时会受到多种口腔内环境复杂因素的影响,导致铬离子释放特性的变化。本文依据口腔修复体形态的相应条件设计钴铬合金试件的大小。通过体外模拟口腔内pH值、温度及时间的变化来研究这三种因素对应用于口腔的钴铬合金中钴、铬离子释放特性的影响。为选择具有良好的耐腐蚀性能的牙科合金材料,以及后续试验中析出的钴、铬离子的性质对人体的影响提供实验依据。方法采用临床口腔修复常用的钴铬合金试件,称量后将试件放入棕色带盖的容量瓶中,每瓶一件,分别加入PH值为5.0、7.0、9.0的人工唾液和PH值为7.0的纯水(100m1)。人工唾液组放入8℃、37℃和45℃恒温孵育箱中,每组3瓶；纯水组放入37℃恒温孵育箱中。分别进行静态浸泡2周、4周、6周、8周。进行各种设定条件下的铬、钴离子析出实验。采用电感耦合等离子质谱法(ICP-MS)检测各瓶溶液中析出的铬、钴离子浓度,数据进行统计分析。结果1.pH=7.0,温度为37℃时,钴铬合金分别浸泡于人工唾液和纯水中,钴、铬离子的析出浓度在人工唾液中均高于纯水,差异有统计学意义(p<0.05),在不同时间点上钴、铬离子的析出量不同,差异有统计学意义(p<0.05),且浸泡液和时间对钴、铬离子的析出均有交互作用(p<0.05).2.温度为37。C时,pH=5.0时,钴铬合金中析出的铬离子量随时间逐渐增加,钴离子从第2周析出速度达高峰。对不同pH值组进行两两比较,pH=7.0组和pH=9.0组差异没有统计学意义(p>0.05),其他任意两组差异有统计学意义(p<0.05)。3.pH=7.0时,不同温度条件下,铬、钴离子的析出量不同,且温度与时间对钴、铬离子的析出有交互作用。温度为45℃、处理时间为8周时铬离子的析出速度最快。4.时间为第4周时,不同pH值组之间,钴、铬离子的析出浓度均有差异(p<0.05),任意两组之间差异有统计学意义,不同温度之间钻、铬离子的析出也均有差异,温度(T)=45。C组>T=8℃组>T=37℃组,且任意两组之间差异有统计学意义(p<0.05),pH值和温度有交互作用。5.温度为37℃时,不同时间点,失重的质量不同,随着时间的延长,失重质量增多,不同pH组之间失重的质量不同,差异有统计学意义(p<0.05)。pH值和时间对钴铬合金的失重质量不存在交互作用(p>0.05)。不同pH值组失重的线性变化趋势明显不同(p=0.000)。结论(1)钴、铬离子的析出浓度在人工唾液中均高于纯水。(2)pH值、温度和时间对钻铬合金试件在人工唾液中金属离子的析出有影响,即钴铬合金试件在偏酸或偏碱、低温或高温条件下分别比pH值为7.0、温度为37℃时的铬、钴离子析出量要多,并随时间的延长而增加。pH值与时间、温度和时间之间有交互作用。更多还原

【Abstract】 ObjectiveCobalt-chromium alloy is widely used in dentistry because of its fine biological compatibility and cheap price. However, when the cobalt-chromium is bedded in oral cavity, it would release heavy metal ions such as chromium ions, which can be absorbed by organs resulting in swollen gums and allergy reaction. Recently, more and more people concerned about the security problem of clinical application of cobalt-chromium alloy. The Co-Cr dental casting alloy applied to the dental restore can be affected by varies complicated factors resulting in the change of metal ions release. This study designs the Co-Cr dental casting alloy size according to the human dental superficial area. This study is aimed to investigate the effect of different factors on the metal ions release of Co-Cr dental casting alloy by in vitro simulating the oral cavity condition such as the changes of pH values, temperature and exposure time. The experimental results provide experimental evidence for the Co-Cr dental casting alloy applied to clinic and proving the corrosion resistance.MethodsThis study adopted Co-Cr dental casting alloy test specimen. The test specimen were put into the artificial saliva with the different pH values of5.0,7.0and9.0, and at different temperature (8℃,37℃,45℃), respectively. The group of pure water was put in the37℃stable temperature culture box. Then the soak solution were measured the chromium ions and cobalt ions concentration by inductively coupled plasma atomic emission spectrometry, ICP-MS at different time point (2w,4w,6w,8w). The data were performed statistical analysis using SPSS13.0statistical software. Results(1) At the pH level of7.0, the Co-Cr dental casting alloy soaked in the artificial saliva and pure water respectively, the concentrations of both the cobalt and chromium ions are higher in the artificial saliva than in the water. The concentrations of two kind of metal ions are both different at different time point, with statistical significance (p<0.05), and there is a significant interaction between artificial saliva and pure water on the release of cobalt and chromium ions from Co-Cr dental casting alloy.(2) Chromium ions release from Co-Cr alloy has time-dependence at37℃temperature with the pH=5.0. Cobalt release from Co-Cr alloy has increased arriving peak at the4th week. Three groupa of different PH values were performed Student Newman Keuls test, any two groups have statistical significant difference (p<0.05), except the groups between PH=7.0andpH=9.0.(3) Both of cobalt and chromium ions release from Co-Cr alloy are different among different temperature. There is a significant difference interaction between pH values and temperature on the release of cobalt and chromium ions from Co-Cr dental casting alloy. At the8th week the speed of chromium ions reach the highest when T=45℃.(4) When the Co-Cr dental casting alloy had been soaking for4weeks, both cobalt and chromium ions release are different among3pH values groups, pH5.0group>pH9.0group>pH7.0group, with statistical significant difference (p<0.05). The concentration of cobalt and chromium ions are both different in different temperature groups, T=45℃group>T=8℃group>T=37℃group with statistical significant difference (p<0.05). There is a significant difference interaction between pH values and temperature on the release of cobalt and chromium ions from Co-Cr dental casting alloy, with statistical significance (p<0.05).(5) The mass difference of Co-Cr dental casting alloy are higher at the pH level of5.0than other pH groups, with significant difference (p<0.05) at37℃temperature. The mass difference has significance at different time point, and it is time-dependent. The liner change tendency of mass difference are different at different pH levels (p=0.000). There is a significant difference between pH level and temperature on the mass difference of Co-Cr dental casting alloy with significant difference (p>0.05).Conclusion(1) Artificial saliva has effect on the metal ions release of Co-Cr dental casting alloy.(2) The level of pH, temperature and time affect the metal ions release of Co-Cr dental casting alloy. Compared with the condition of PH=7and temperature=37℃, there are more release of Co-Cr dental casting alloy either PH>7or<7, and either lower or higher temperature. And there is a significant difference among them on the release of cobalt and chromium ions from Co-Cr dental casting alloy in artificial saliva.更多还原