Viscoelastic Properties and Durability of Photo-activated Soft Lining Materials for Denture Base

1. 1997年的学习计划。浇注商业软衬材料（CMs: CS， LN， SL， TS）分别储存在每种溶液中(DW：蒸馏水，SC：等渗氯化钠溶液（0.9%）；AS：人工唾液)在37℃下放置8周，按照制造商的说明书使用七种义齿基托清洁剂进行清洁。并对四种CMs的粘弹性及降解性能进行了研究。所得结果如下：(1)浸泡前，cm的硬度（Hex）为21.1 ~ 44.7，在每种溶液中保存2周后，硬度（Hex）增加到104.6 ~ 132.7%。(2)浸没前cm的反射率为20（无光面）~ 70（高光面）。随着贮藏时间的延长，CM （GS）的值有降低的趋势，而其他CM （LN、SL、TS）的值变化不显著。(3)浸泡前，cm的接触角在35 ~ 40“*”之间。在DW和sc中存放1 d后，两种cm （CS、SL）的More值略低于浸泡前。然而，在每种溶液中储存3天至8周期间，所有CMs的值变化不显著。(4)浸泡前，cm的表面粗糙度在2 ~ 8 μ m之间。这些值随着贮存期的增加而增加。(5) 3种cm （CS、LN、TS）在开始浸泡后3-7天内，试件表面出现大量空洞。1998年的学习计划。根据1997年获得的数据。制备了以聚甲基丙烯酸乙酯（PEMA）为主要成分的粉末，以邻苯二甲酸二丁酯（DBP）为增塑剂、甲基丙烯酸乙酯（EMA）、光敏剂、还原剂和乙醇（Et）为主要成分的9种实验性光活化软衬材料（epm），其粉液比为1.38。在本研究中，从9种epm中选取了硬度值与cm基本相等的4种epm （M1D8E0、M1DSE0.5、M1D8E1、M1D8E1.5）。四种EPMs组成的液体为EMA: DBP，比例为1:8，Et添加在0-14.3wt%范围内。测量方法与描述的cm相同。由于粘弹性随epm的变化还在继续，尚未得出结论，但目前得到的结果如下：也就是说，Et含量较低的epm （MID8E0, M1D8E0.5）表现出优异的耐久性能

1. On study plan in 1997. Pour commercial soft lining materials (CMs : CS, LN, SL, TS) were stored in each solution (DW : distiied water ; SC : isotonic sodium-chloride solution (0.9%) ; AS : artificial saliva) for 8 weeks at 37"*"C, with cleaning by using seven denture base cleansers in accordance with manufacture's instruction. And viscoelastic property and degradation of four CMs were investigated. The results obtained were as follows.(1) Before immersion the hardness(Hex) of the CMs ranged from 21.1 to 44.7 and these values increased up to 104.6-132.7% after storage in each solution for 2 weeks.(2) Before immersion the light reflectivity of the CMs ranged from 20 (none glossy surface to 70 (high glossy surface). The values of the CM (GS) were apt to decrease with increasing storage period and however the values of other CMs (LN, SL, TS) showed insignificant change.(3) Before immersion the contact angle of the CMs ranged from 35 to 40"*". After I day of storing in the DW and SC.the … More values of two CMs (CS, SL) were slightly lower than those before immersion. However, the values of all CMs showed insignificant change between 3 days and 8 weeks stored in each solution.(4) Before immersion the surface roughness of the CMs ranged from about 2' to 8 mum. These values increased with increasing storage period.(5) Many hollows on the specimen surface of three CMs (CS, LN, TS) were observed within 3-7 days from start of immersion.2. On study plan in 1998. On the basis of the data obtained in 1997. the nine experimental photo-activated soft lining materials (EPMs) were produced, which the powder as a main component was polyethylmethacrylate (PEMA) and the liquid consists of di-n-butyl phthalate (DBP) as plasticizer, ethylmethacrylate (EMA), photo-sensitizer, reducing agent and ethanol(Et), and the powder-to-liquid ratio was 1.38. in this study, four EPMs (M1D8E0, M1DSE0.5, M1D8E1, M1D8E1.5), which the hardness valus were almost equal to those of the CMs, were selected out among the nine EPMs. A formation of the liquid with four EPMs was EMA : DBP in the ratio 1 : 8 and Et added within 0-14.3wt%. Measurements were performed by means of the same as that described for the CMs. Although no conclusion has been reached because the change of viscoelastic property with the EPMs is now being continued, the results obtained till now are as follows. Namely it could be seen that the EPMs (MID8E0, M1D8E0.5) with lower percentage of Et exhibited an excellent durability Less