Department of Dentistry, Federal University of Sergipe, Rua Cláudio Batista s/n, Aracaju, SE, Brazil.
Department of Biomaterials and Biomechanics, Oregon Health & Science University, 2730 SW Moody Ave., 97201, Portland, OR, USA.
Dent Mater. 2017 Nov;33(11):1274-1285. doi: 10.1016/j.dental.2017.07.020. Epub 2017 Aug 12.
This study evaluated the effects of filler type and the addition of thio-urethane oligomers on light-transmission, polymerization kinetics and depth of cure of resin composites.
BisGMA:UDMA:TEGMA (5:3:2wt%) were mixed with 0 (control) or 20wt% thio-urethane. Fillers with various sizes and refractive indices were included and refractive index (RI) measured. Unfilled resins were used as controls. The RIs of materials were measured before and after polymerization. The irradiance reaching the bottom of 3-mm thick specimens was measured during the polymerization. Degree of conversion to a depth of 5mm was mapped. An optical bench was used to simultaneously follow conversion and light transmission.
The addition of thio-urethane increased the RI for all composites. As expected, RI also increased with conversion for all materials. The one exception was for the material filled with OX-50, in which the RI of the composite decreased with conversion. In this case, the irradiance at the bottom of the 3mm specimen was also the lowest among all groups. The addition of thio-urethanes had only minimal effect on light transmission within a filler type, but led to increased conversion in depth for all groups. The filler type itself had a greater effect on light transmission, and that correlated well with the degree of conversion.
The effect of the thio-urethane addition on degree of conversion in depth was dependent on filler type. The additive can be tailored to improve the RI match with the filler to optimize light transmission in dental composites.
本研究评估了填料类型和硫代尿烷低聚物的添加对树脂复合材料透光率、聚合动力学和固化深度的影响。
BisGMA:UDMA:TEGMA（5:3:2wt%）与 0（对照）或 20wt%硫代尿烷混合。包含各种尺寸和折射率的填料，并测量折射率（RI）。未填充的树脂用作对照。聚合前后测量材料的折射率。测量 3mm 厚样本底部的辐照度。映射到 5mm 深度的转化率。使用光学台同时跟踪转化率和透光率。
硫代尿烷的添加增加了所有复合材料的 RI。正如预期的那样，所有材料的 RI 都随转化率的增加而增加。唯一的例外是填充 OX-50 的材料，其中复合材料的 RI 随转化率的增加而降低。在这种情况下，3mm 样本底部的辐照度也是所有组中最低的。在给定填料类型内，硫代尿烷的添加对光透过率的影响很小，但会增加所有组的深度转化率。填料类型本身对光传输的影响更大，这与转化率很好地相关。
硫代尿烷添加对深度转化率的影响取决于填料类型。可以对添加剂进行定制，以改善与填料的 RI 匹配，从而优化牙科复合材料的光传输。
