Can Composition and Pre-heating Improve the Infiltrant Characteristics and Penetrability in Demineralized Enamel?

Objectives: To evaluate the pre-heating effect and composition of infiltrants on the physical properties and penetration depth in demineralized enamel.
Methods: The groups were assigned as either [Icon®] or experimental formulations [25% BisEMA, 75% TEGDMA], [25% BisEMA, 65% TEGDMA, 10% ethanol], [25% BisEMA, 65% TEGDMA, 10% HEMA], [100% TEGDMA], [90% TEGDMA, 10% ethanol], or [90% TEGDMA, 10% HEMA], and tested at two temperatures (25 and 55°C). Degree of Conversion (DC) (n = 3), Elastic Modulus (E) (n = 10), Flexural Strength (FS) (n = 10) and Contact Angle (CA) (n = 5) tests were performed. penetration depth of infiltrant was verified by Confocal Laser Scanning Microscopy (CLSM). 2-Way ANOVA and Tukey’s test (α=5%) used for statsical analyses.
Results: For all materials, the DC was less than 50% at 25°C. However, the DC was greater than 60% after pre-heating. Pre-heating did not influence E or FS. The E value of the [25% BisEMA, 65% TEGDMA, 10% HEMA] was higher than the other groups, while the lowest E was found to [90% TEGDMA, 10% ethanol]. For most groups, the contact angle increased after heating to 55°C. However, HEMA containing group had a decreased contact angle after pre-heating. The [100% TEGDMA] composition showed a more homogeneous penetration, whereas the Icon® group had a heterogeneous and superficial penetration.
Conclusions: Pre-heating of infiltrants improved the DC of all tested groups and decreased the CA for groups containing HEMA, but did not affect E or FS. Infiltrants containing solvents had the lowest values of DC, E, and FS. The penetration depth was not influenced by the temperature. The Icon® group had the shallowest penetration depth.