Effect of Flowable Composite Intermediate Layer on Bond Strength of Intra-Oral Porcelain Repair: An In-Vitro Study

Aims: The aim of this study was to investigate the effect of flowable composite, as an intermediate layer between feldspathic porcelain and composite, on bond strength during intra-oral porcelain repair and its potential role in providing a long-lasting repair. Methods: Forty feldspathic porcelain (VMK 95) specimens were fired in metal ingots. They were airborne-particle abraded, etched with 4% hydrofluoric acid gel (Porcelain Etch), and then silane (Porcelain Primer) was applied. Specimens were randomly allocated to one of three study groups or to the control group (ten to each of the four groups). After the application of the bonding agent (One-step), one of the following flowable composites was applied using a brush to specimens in each study group: Filtek Flow, Tetric Flow, or Aelite Flo LV. Flowable composite was not used in the control group. a hybrid composite (Z-100) was applied to the bonding surfaces of specimens in all groups. Specimens were stored in distilled water at 37oC for 24 hours and then subjected to shear testing (MPa) using a universal testing machine at 0.50mm/min. Treatment effect was tested by analysis of variance (one-way ANOVA). Results: Mean MPa ±SD values for each test group were as follows: Filtek Flow, 16.40 ±4.19; Tetric Flow, 13.75 ±4.0; Aelite Flo LV, 15.03 ±4.34; for the control group, 15.37 ±2.20. The fractured surfaces showed cohesive failures in the porcelain, with the exception of those treated wtih Aelite Flo LV which exhibited adhesive failures. Conclusion: Flowable composite does not appear to enhance the shear bond strength of intra-oral porcelain repair.