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 本研究评估了在含或不含热循环（thermocycling）处理的实验性窝沟封闭剂中添加疏水单体1,12-十二烷二醇二甲基丙烯酸酯（1,12 dodecanediol dimethacrylate，DDDMA），对固化转化率（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）的影响。共纳入5种实验性封闭剂与1种市售封闭剂（Bisco - BIS）进行测试。实验性封闭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）配制得到。光引发体系由樟脑醌（camphorquinone，CQ）与叔胺类助剂4-乙基苯甲酸二甲基氨基酯（4-ethyl benzoate dimetilamiono，EDBA）组成，以乙醇作为溶剂。实验分组依据单体配比（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）分别进行统计分析，随后采用Tukey检验进行多重比较，检验水准设定为p<0.05。固化转化率的取值范围为94.59%（S40/40）至54.02%（S80/10）。市售封闭剂BIS的吸水率最高（p<0.05），而S40/40、S50/30、S60/20及S80/0的吸水率为所有受试封闭剂中最低。水溶解度的取值范围为7.88 µg/mm³（BIS）至13.27 µg/mm³（S70/10）。市售封闭剂BIS的颜色稳定性最差，其ΔE值最高可达11.05±2.88；S60/20的微剪切粘结强度最高。经热循环处理后，各封闭剂与牛牙釉质间的粘结强度未观察到显著差异。向表面封闭剂的配方中添加DDDMA可改善其综合性能，该单体可提升固化转化率与颜色稳定性。