Influence of a hydrophobic monomer on the physical and mechanical properties of experimental surface sealants

Abstract This study evaluated the effect of adding the hydrophobic monomer 1,12 dodecanediol dimethacrylate (DDDMA) to experimental sealants with and without thermocycling on degree of conversion (DC), water sorption (WS), water solubility (WSB), color stability (ΔE), and micro-shear bond strength (μSBS). Five experimental and one commercially available sealant (Bisco - BIS) were tested. The experimental sealants were formulated by mixing different percentages of DDDMA monomers and urethane dimethacrylate (UDMA). The photoinitiator system was composed by camphorquinone (CQ) and tertiary amine 4-ethyl benzoate dimetilamiono (EDBA). Ethanol was used as a solvent. The experimental groups were named sequentially according to the monomeric content (DDDMA/UDMA): S40/40 (40/40), S50/30 (50/30), S60/20 (60/20), S70/10 (70/10) and S80/0 (80/0). Data were analyzed separately by one-way ANOVA, followed by Tukey’s test (p<0.05). The values of DC ranged from 94.59% (S40/40) to 54.02% (S80/10). BIS showed the highest WS value (p<0.05) and S40/40, S50/30, S60/20 and S80/0 showed the lowest WS values of all tested sealants. WSB values ranged from 7.88 µg/mm3 (BIS) to 13.27 µg/mm3 (S70/10). The highest ΔE value was 11.05±2.88 for BIS and the highest μSBS value was found for S60/20. No significant difference was observed in bond strength between sealants and bovine enamel after thermocycling. Adding DDDMA to the composition of surface sealants can improve its performance, once the monomer increased the degree of conversion and the color stability.

摘要 本研究评估了将疏水单体1,12-十二烷二醇二甲基丙烯酸酯（1,12 dodecanediol dimethacrylate，DDDMA）添加至实验性密封剂（experimental sealants）后，经热循环（thermocycling）与未经热循环处理的试样在转化率（degree of conversion，DC）、吸水率（water sorption，WS）、水溶解度（water solubility，WSB）、颜色稳定性（color stability，ΔE）及微剪切粘结强度（micro-shear bond strength，μSBS）上的性能变化。本研究共测试5种实验性密封剂与1种市售密封剂（Bisco-BIS）：实验性密封剂通过按不同比例混合DDDMA单体与氨基甲酸酯二甲基丙烯酸酯（urethane dimethacrylate，UDMA）制备得到，光引发体系（photoinitiator system）由樟脑醌（camphorquinone，CQ）与叔胺4-乙基苯甲酸二甲基氨基酯（4-ethyl benzoate dimetilamiono，EDBA）组成，并以乙醇作为溶剂。实验分组按照单体配比（DDDMA/UDMA）依次命名为S40/40（40/40）、S50/30（50/30）、S60/20（60/20）、S70/10（70/10）及S80/0（80/0）。数据采用单因素方差分析（one-way ANOVA）单独分析后，辅以Tukey检验（Tukey’s test）进行多重比较（p<0.05）。各组DC值介于94.59%（S40/40）至54.02%（S80/10）之间；BIS的WS值最高（p<0.05），S40/40、S50/30、S60/20与S80/0的WS值为所有受试密封剂中最低。WSB值介于7.88 µg/mm³（BIS）至13.27 µg/mm³（S70/10）之间；BIS的ΔE值最高，为11.05±2.88，S60/20的μSBS值最高。经热循环处理后，各密封剂与牛釉质（bovine enamel）间的粘结强度无显著差异。将DDDMA添加至表面密封剂的配方中可改善其性能，该单体可提升密封剂的转化率与颜色稳定性。