Delayed photo-activation and addition of thio-urethane: Impact on polymerization kinetics and stress of dual-cured resin cements.
Delayed photo-activation and addition of thio-urethane: Impact on polymerization kinetics and stress of dual-cured resin cements.
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DOI：
10.1016/j.jdent.2017.07.014
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发表时间：
2017-10
影响因子：
4.4
通讯作者：
Pfeifer CS
中科院分区：
文献类型：
--
作者：
Faria-E-Silva AL;Pfeifer CS
1) 确定双固化水泥氧化还原聚合反应期间光活化材料以减少聚合应力的时刻，2) 评估添加链转移剂和延迟光活化之间可能的协同效应。将实验性双固化材料的两种糊剂混合，并跟踪氧化还原相的聚合动力学。确定材料达到水泥的最大氧化还原聚合速率（MRRP）时的时刻。评估材料的转化度 (DC) 和最大聚合速率 (Rpmax)，其中：材料混合后立即进行光活化，在 MRRP 下，在 MRRP 之前 1 分钟和之后 1 分钟。合成硫代聚氨酯（TU）添加剂并将其添加到水泥（20％wt）中，然后在相同条件下固化。对立即光活化或在 MRRP 下光活化的两种水泥的聚合动力学进行了评估，然后测量聚合应力、弯曲强度 (FS) 和弹性模量 (EM)。在乙醇储存之前和之后测量努氏硬度。在 MRRP 时或之后对水泥进行光活化可降低 Rpmax 和聚合应力。 TU 的添加促进了额外且更显着的降低，同时不影响 Rpmax。对于含有 TU 的水泥，观察到更大的硬度损失，但所有实验条件下的最终硬度相似。 TU 的添加略微降低了 EM，但不影响 FS。延迟光活化和添加 TU 显着降低了双固化水泥的聚合应力。
1) to determine the moment during the redox polymerization reaction of dual cure cements at which to photo-activate the material in order to reduce the polymerization stress, and 2) to evaluate possible synergistic effects between adding chain transfer agents and delayed photo-activation. The two pastes of an experimental dual-cure material were mixed, and the polymerization kinetics of the redox phase was followed. The moment when the material reached its maximum rate of redox polymerization (MRRP) of cement was determined. The degree of conversion (DC) and maximum rates of polymerization (Rpmax) were assessed for materials where: the photoactivation immediately followed material mixing, at MRRP, 1 min before and 1 min after MRRP. Thio-urethane (TU) additives were synthesized and added to the cement (20% wt), which was then cured under the same conditions. The polymerization kinetics was evaluated for both cements photo-activated immediately or at MRRP, followed by measurements of polymerization stress, flexural strength (FS) and elastic modulus (EM). Knoop hardness was measured before and after ethanol storage. Photo-activating the cement at or after MRRP reduced the Rpmax and the polymerization stress. Addition of TU promoted additional and more significant reduction, while not affecting the Rpmax. Greater hardness loss was observed for cements with TU, but the final hardness was similar for all experimental conditions. Addition of TU slightly reduced the EM and did not affect the FS. Delayed photo-activation and addition of TU significantly reduce the polymerization stress of dual-cured cements.
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影响因子：
5
作者：
Bacchi, Atais;Pfeifer, Carmem S.
通讯作者：
Pfeifer, Carmem S.
影响因子：
5
作者：
Lu, H;Stansbury, JW;Bowman, CN
通讯作者：
Bowman, CN
DOI：
10.1002/jbm.b.30088
发表时间：
2004-10-15
影响因子：
3.4
作者：
Lu, H;Stansbury, JW;Bowman, CN
通讯作者：
Bowman, CN
影响因子：
7.6
作者：
Pfeifer, C. S.;Ferracane, J. L.;Braga, R. R.
通讯作者：
Braga, R. R.
DOI：
10.1016/j.dental.2015.02.008
发表时间：
2015-05
期刊：
Dental materials : official publication of the Academy of Dental Materials
影响因子：
--
作者：
Bacchi A;Consani RL;Martim GC;Pfeifer CS
通讯作者：
Pfeifer CS