The Effect of Preheating on Light Cured Resin Composites

抄録

This paper is intended to offer a theoretical basis for clinical appliance of preheating by comparing the properties of six different resin composites at room temperature and pre-heated temperature.
The experiment is divided into two groups: one at room temperature (20°C), the other at preheated temperature (60°C). At room temperature, the six resin composites were exposed to a LED light for 20 seconds. While in the other group, the resins were firstly put into an incubator which is elevated to 60°C, and then taken out. After 60 seconds, they were exposed to LED light for 20 seconds. In each group, the compressive strength, micro Vickers hardness and the degree of conversion of six resin composites were tested. After being filled with resin composites, the extracted teeth were dyed and sliced. The microleakage of the restoration was observed and then recorded. All the data was analyzed by statistical analyses. Preheating has no apparent effect on compressive strength, hardness and degree of conversion of Filtek^TMZ350, Surefil, Solitaire2, ESTELITEΣ, BRILLIANT New Line, but significantly improved the compressive strength and the hardness of GRADIA DIRECT. And preheating also reduces the microleakage of resins, especially for Surefil and Solitaire2. Preheating has effect on the properties of resin composites, and different resins differ in the sensitivity to preheating due to their different components and contents. In clinical, we ought to fully consider the value of preheating according to requirement in order to obtain the benefit.