Microleakage Evaluation of Delayed Versus Immediate Light Cured Flowable Composite

Objectives: The purpose of this study is to observe Class II restorations treated with flowable composite combined with non-flowable composite with immediate and delayed light-cure methods.

Methods: A total thirty standard Class II preparations were performed on non-carious human third molar teeth by the same operator. The preparations were approximately 2.0-mm in depth at the occlusal floor and 4.0-mm in depth at the gingival floor. Samples were etched with 37% H₂PO₄ and bonding agent (Peak LC, Ultradent) was applied according to manufacturer instructions and restored according to their randomly assigned group. After restorations were completed, samples were thermo-cycled for 2,500 cycles, immersed in 50% ammoniacal silver nitrate solution for three hours then immersed in photo-developing solution for sixteen hours. Samples were embedded in acrylic and sectioned longitudinally across the gingival floor. Dye penetration scores were measured under a light-microscope (Olympus SZX16)

 

Group (n=10)	Curing Method	Flowable Composite	Non-flowable Nanocomposite
1	Immediate	None	Filtek-Supreme  (3M)
2	Immediate	PermaFLO (Ultradent)	Filtek-Supreme
3	Delayed	PermaFLO	Filtek-Supreme

 

Results: Using the Kruskal-Wallis one-way ANOVA test significant difference was found between the groups (p-value = .002). Group-1 was significantly different from Group-2 (< .001) using the Mann-Whitney U-test with the Bonferroni correction.

 

Dye Penetration (DP)Score	Group 1	Group 2	Group 3
0 = No dye penetration (DP)	0	5	3
1 = DP to 25% of gingival floor (GF)	0	2	0
2 = DP to 50% of GF	1	1	3
3 = DP to 75% of GF	4	2	1
4 = DP to axial wall	5	0	3
n=	10	10	10

 

 

Conclusions: Based on the statistical results there was no significant difference between delayed versus immediate light-curing techniques. It was also evident that using flowable composite as a liner provided better marginal adaptation on the gingival floor of the restoration.