Abstract
BackgroundThe aim of this study is to compare the microleakage of Class II dental composite resin restorations which have been cured by three different LED (light emitting diode) light curing modes compared to control samples cured by QTH (quartz tungsten halogen) light curing units (LCUs), to determine the most effective light curing unit and mode of curing.ResultsIn this experimental study, class II cavities were prepared on 100 sound human premolars which have been extracted for orthodontic treatment. The teeth were randomly divided into four groups; three experimental and one control group of 25 teeth each. Experimental groups were cured by either conventional, pulse-delay, or ramped curing modes of LED. The control group was cured for 20 seconds by QTH. The restorations were thermocycled (1000 times, between 5 and 55°C, for 5 seconds dwell time), dyed, sectioned mesio-distally and viewed under stereo-microscope (40×) magnification. Teeth were then scored on a 0 to 4 scale based on the amount of microleakage. The data were analyzed by Chi-square test.No significant difference was demonstrated between the different LCUs (light curing units), or modes of curing, at the enamel side (p > 0.05). At the dentin side, all modes of LED curing could significantly reduce microleakage (p < 0.05). The results suggest that slow start curing improves marginal integrity and seal. High intense curing endangers those aims.ConclusionsComparison between the three LED mode cured composite resin restorations and QTH curing showed LED curing in all modes is more effective than QTH for reducing microleakage. Both LED and QTH almost completely eliminate the microleakage on the enamel side, however none of them absolutely eliminated microleakage on the dentin side.
Highlights
The aim of this study is to compare the microleakage of Class II dental composite resin restorations which have been cured by three different LED light curing modes compared to control samples cured by QTH light curing units (LCUs), to determine the most effective light curing unit and mode of curing
Both LED and QTH almost completely eliminate the microleakage on the enamel side, none of them absolutely eliminated microleakage on the dentin side
The control group was cured for 20 seconds by QTH (Figure 6, Bonart, ART-L2, Xinzhuang District, New Taipei City, Taiwan)
Summary
The aim of this study is to compare the microleakage of Class II dental composite resin restorations which have been cured by three different LED (light emitting diode) light curing modes compared to control samples cured by QTH (quartz tungsten halogen) light curing units (LCUs), to determine the most effective light curing unit and mode of curing. Resin-based composites are synthetic resins which are used in dentistry for tooth restoration, or as an adhesive. There are two types of tooth colored restorative materials; self-cured and light-cured resins. In comparison with a common alternative restoration material, amalgam, synthetic resins exhibit superior aesthetics. High demand for tooth colored restorations in anterior and posterior teeth has triggered investigations of composite resin characteristics to improve poor outcomes such as microleakage which affects durability of tooth colored restorations, leading to restoration failure as well as post-operative sensitivity [1]. Insufficient polymerization due to poor curing, leads to increased water absorption, and compromised mechanical characteristics including less hardness, more erosion, micro-leakage, secondary caries, and as a consequence, failure of the composite filling [2,3]. One way to combat these problems is to select the best light curing system
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