Margin integrity of ClassII Preparations Restored with the SonicFill System

Objective: A new sonic-activated resin system has been introduced that allows for improved placement in bulk.  This study will compare its marginal adaptation with other conventional composite resins.

Method:

Thirty human molars were prepared with Class II restorations standardized to the following dimensions: 4mm bucco-lingually, 5mm mesio-distally, 4mm depth, and the proximal box placed 0.5 mm below the CEJ. The teeth were then randomly divided into three groups:

A: SonicFill + Optibond AIO (Kerr Corp.), B: SureFil SDR + Xeno IV + Ceram X (Dentsply) and C:Filtek Supreme Ultra + Adper Easy Bond (3M).  The teeth were restored following manufacturers recommendations, polished and thermocycled for 1000 cycles at 5-55 ⁰C.  Epoxy replicas were made from PVS impressions and marginal analysis was performed on the replicas under SEM at 200X. The margins were scored as follows:

1 = Continuous margin

2 = Margin imperfections/Hairline crack

3 = Marginal opening < 2μm

4 = Marginal gap > 2μm

The teeth were then sectioned in half and the same process was used to assess the internal marginal integrity.

The percentage in length corresponding to each scored was calculated and differences were assessed using non-parametric ANOVA.

Result: Overall, SonicFill showed a higher percentage of samples with totally continuous internal margins (70%) than Surefil (40%) and Filtek (40%). For the external margins, SonicFill and SureFil showed the same number of totally sealed specimens (40%) while Filtek revealed a lower percentage (10%). However, the number of samples showing perfectly sealed margins (100% continuous) did not show significant differences among the materials (p=0.242)

Conclusion: SonicFill showed similar internal and external marginal sealing than the other two composites.