Bulk-fill Composite Effect on Proximal Contact Tightness of MO Restorations

Objectives: This study investigated the effect of bulk-fill composites on proximal contact tightness (PCT) of mesio-occlusal (MO) composite restorations using different matrix systems.
Methods: 150 ivorine teeth with standardized MO cavity preparations were divided into 5 equal groups; G-ænial Universal Flo (GF) (GC Europe), Smart Dentin Replacement (SDR) (Dentsply, USA), SonicFill (SF) (Kerr, USA), Tetric EvoCeram Bulk-Fill (TEB) and Tetric EvoCeram (TE) (IvoclarVivadent, USA). Each group was further subdivided into three sub-groups (n=10) according to the matrix systems used; conventional metal tofflemire matrix(KerrHawe 1101-c), sectional metal matrix attached to wedge(FenderMate, Diretca, Sweden) and sectional metal matrix with separation ring(Palodent plus, Dentsply, USA). All restorations were carried out in a clinically-relevant situation using KaVo manikin head with corresponding bonding systems following manufacturer’s instructions and light cured for 20s/increment(2mm for GF and TE and 4mm for SDR, SF and TEB) with Elipar-S10(3M/ESPE, USA). PCT was measured using Tooth Pressure Meter(University of Technology, Delft). Each proximal contact measurement was an average of 3 readings, means were calculated and data were statistically-analyzed using ANOVA and Tukey’s test (p<.05).
Results: Means and standard deviations of PCT for tofflemire subgroup were: 2.49(.21), 1.75(.13), 3.21(.1), 3.06(.19) and 3.18(.1) for GF, SDR, SF, TEB and TE respectively. Using FenderMate, values were: 2.64(.1), 1.87(.08), 3.35(.12), 3.17(.16) and 3.26(.11) for GF, SDR, SF, TEB and TE respectively, while with Palodent plus, values were: 3.46(.17), 3.16(.17), 4.23(.11), 4.1(.1) and 3.98(.1) for GF, SDR, SF, TEB and TE respectively. ANOVA revealed significant difference between all materials except between SF, TEB and TE and also significant difference between separation ring and the other two matrix systems.
Conclusions: Effect of bulk-fill composites on PCT is material dependent as SF and TEB showed comparable PCT. Separation ring is recommended to obtain proper PCT in MO composite restorations.Acknowledgements: 3M/ESPE, Dentsply, Directa, GC Europe and Kerr.