Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK.
Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK.
Dent Mater. 2020 Jun;36(6):787-793. doi: 10.1016/j.dental.2020.03.025. Epub 2020 May 5.
To evaluate the effects of pre-heating time and exposure duration on the degree of conversion (DC), maximum rate of polymerization (RP), polymerization shrinkage strain (PS) and surface micro-hardness (VHN) of Viscalor.
Viscalor syringes were pre-heated using a Caps Warmer (VOCO, Germany) in T3 mode (at 68°C) for 30s (T3-30s) and 3min (T3-3min) and then the composite paste was extruded into appropriately sized molds. Light irradiation was applied at zero distance from the upper surface with a LED-LCU of mean irradiance 1200mW/cm for either 20 or 40s. The real-time polymerization kinetics and DC at 5min and 24h post-irradiation (DC and DC) were measured using ATR-FTIR (n=3). PS was obtained with the bonded-disk technique (n=3). Top and bottom Vickers micro-hardness (VHN and VHN) were measured at 5min post-irradiation and after 24h dry storage (n=5). Data were analysed using one-way ANOVA, two-way ANOVA, independent t-test and Tukey post hoc tests (p<0.05).
Polymerization kinetic curves of Viscalor from 0 to 15min were similar for different pre-heating times and exposure durations. Pre-heated Viscalor (T3-30s and T3-3min) with 40s exposure had greater VHN and VHN than for Viscalor (no heat) (p<0.05). Exposure duration did not significantly affect DC, RP and PS (p>0.05). After 24h storage, DC and VHN increased. Pre-heating did not increase the DC, relative to no pre-heating (p>0.05). Two-way ANOVA showed that there was no significant interaction between pre-heating time and exposure duration (p>0.05).
Increasing irradiation time from 20 to 40s did not affect DC, RP or PS, but increased VHN. Composite pre-heating had no adverse effect through any premature polymerization. For Viscalor, 3min pre-heating and 20s irradiation were sufficient to provide adequate hardness, without increasing PS or compromising polymerization kinetics.
评估预热时间和曝光时间对 Viscalor 转化率（DC）、最大聚合率（RP）、聚合收缩应变（PS）和表面显微硬度（VHN）的影响。
使用 Caps Warmer（VOCO，德国）在 T3 模式下（68°C）对 Viscalor 注射器进行 30s（T3-30s）和 3min（T3-3min）的预热，然后将复合糊剂挤出到适当大小的模具中。使用平均辐照度为 1200mW/cm 的 LED-LCU 在距离上表面零距离处进行光照，时间分别为 20s 和 40s。使用 ATR-FTIR（n=3）测量 5min 和 24h 后照射的实时聚合动力学和 DC（DC 和 DC）。使用结合盘技术（n=3）获得 PS。在照射后 5min 和 24h 干燥储存后测量顶部和底部维氏显微硬度（VHN 和 VHN）（n=5）。使用单向方差分析、双向方差分析、独立 t 检验和 Tukey 事后检验（p<0.05）分析数据。
不同预热时间和曝光时间下 Viscalor 的聚合动力学曲线从 0 到 15min 相似。预热的 Viscalor（T3-30s 和 T3-3min）在 40s 曝光下的 VHN 和 VHN 比 Viscalor（无加热）更高（p<0.05）。曝光时间不会显著影响 DC、RP 和 PS（p>0.05）。储存 24h 后，DC 和 VHN 增加。与不预热相比，预热并没有增加 DC（p>0.05）。双向方差分析显示，预热时间和曝光时间之间没有显著的相互作用（p>0.05）。
将曝光时间从 20s 增加到 40s 不会影响 DC、RP 或 PS，但会增加 VHN。复合预热没有通过任何过早聚合产生不利影响。对于 Viscalor，3min 预热和 20s 曝光足以提供足够的硬度，而不会增加 PS 或影响聚合动力学。
