Geoffrey Pippin, DDS, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA.
Daranee Tantbirojn, DDS, MS, PhD, Department of General Dentistry, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA.
Oper Dent. 2024 Jul 1;49(4):475-483. doi: 10.2341/23-136-L.
Using a wetting resin or adhesive system as an instrument lubricant when placing composite layers is commonly practiced to improve handling. This study investigated whether instrument lubricants affected strength, stiffness, or hardness.
Composite beams (TPH Spectra) were fabricated using a stainless steel mold (25×2.5×2 mm) in two steps, where the second half (12.5 mm) was added and cured against a cured first half (n=15). The composite surface at the open end of the first half was smoothed using an instrument lubricated with wetting resin (Ultradent) or universal adhesive (ScotchBond Universal), enough to prevent sticking, or without lubrication. An additional beam of each group was characterized using scanning electron microscopy. Monolithic specimens were also fabricated. After 24 hour storage (37°C, 100% humidity), the beams' flexural strength and stiffness were determined by four-point bending. Vickers surface hardness was measured on 24-hour composite samples in 2 mm deep acrylic cavities, cured after the surface was smoothed with the two instrument lubricants or no lubricant (n=10). Hardness was remeasured after finishing with a series of contouring and polishing discs. Data were statistically analyzed using ANOVA followed by Student-Newman-Keuls post hoc test at 0.05 significance level.
There were significant differences (p<0.001) in flexural strength and stiffness among groups. While strength and stiffness were not affected by using a wetting resin as instrument lubricant, use of a universal adhesive increased strength and stiffness significantly, achieving monolithic values. Scanning electron micrographs showed less porosities at the interface when using instrument lubricants. Surface hardness was significantly reduced in groups in which instrument lubricants were used, but finishing/polishing restored original hardness (p<0.001).
Lubricating an instrument with a wetting agent did not adversely affect physical or surface properties, provided the surface was finished and polished. If a universal adhesive was used as lubricant, the strength and stiffness of a layered composite could be increased, reaching monolithic values.
在放置复合层时，使用润湿树脂或胶黏剂系统作为器械润滑剂，这是一种常见的提高操作性的方法。本研究旨在探讨器械润滑剂是否会影响强度、刚性或硬度。
采用两步法制作 TPH Spectra 复合梁（不锈钢模具，25×2.5×2mm），其中后半部分（12.5mm）添加并在已固化的前半部分（n=15）上固化。使用润湿树脂（Ultradent）或通用胶黏剂（ScotchBond Universal）润滑器械，以防止粘连的程度平滑前半部分复合材料的开口端，或者不使用润滑剂。每组中还有一个梁用于扫描电子显微镜分析。还制作了整体试件。在 24 小时储存（37°C，100%湿度）后，通过四点弯曲法测定梁的弯曲强度和刚性。在 2mm 深的丙烯酸腔中，对经过两种器械润滑剂或无润滑剂平滑后的 24 小时复合材料样本进行维氏表面硬度测量（n=10）。在完成一系列轮廓修整和抛光盘后，重新测量硬度。使用方差分析（ANOVA）和随后的学生-纽曼-凯斯事后检验（0.05 显著性水平）对数据进行统计学分析。
各组间的弯曲强度和刚性有显著差异（p<0.001）。虽然使用润湿树脂作为器械润滑剂不会影响强度和刚性，但使用通用胶黏剂会显著增加强度和刚性，达到整体值。扫描电子显微镜显示，使用器械润滑剂时界面的孔隙率更小。使用器械润滑剂的组表面硬度显著降低，但经过修整/抛光后恢复到原始硬度（p<0.001）。
如果器械表面经过修整和抛光，使用润湿剂润滑器械不会对物理或表面性能产生不利影响。如果使用通用胶黏剂作为润滑剂，分层复合材料的强度和刚性可以增加，达到整体值。
