Fracture Load of Two PFM Veneering Techniques

Objective: To compare the load to failure of two PFM veneering techniques (press and powder build-up) using two porcelain systems on base and noble substructures.

Methods: Two porcelain systems for PFM were used [InLine (Ivoclar Vivadent) (IL), and Ceramco (Dentsply) (C)] in both layering powder (l) and pressable (p) forms. They were applied to base metal (4all (b), Ivoclar Vivadent, Inc.) and noble metal (Capricorn (n), Ivoclar Vivadent, Inc.). Ten specimens were produced for each condition. Forty replica copings of each metal were waxed and cast with proper substructure support before being oxidized and opaqued. Subsequently, 10 copings of each metal were veneered using one of the four materials: InLine powder (IL-l), InLine POM (IL-p), Ceramco 3 powder (C-l), and Ceramco Press (C-p). The press crowns were fabricated according to each manufacturer's instructions to produce the same occlusal surface. The powder veneered crowns were made using three firings using a polyvinyl matrix to produced the same occlusal surface. The crowns were cemented to a composite base (Heliomolar, Ivoclar Vivadent) using Multilink Automix cement (Ivoclar Vivadent) and stored for 24h in water at 37°C. The crowns were loaded using a 15 mm diameter steel ball at a crosshead speed of 0.5 mm/min with an Instron Universal Testing machine until a crack was produced.

Results: The failure load values (N) of the groups were IL-l-b: 1687±367, IL-p-b: 1807±297, IL-l-n: 1794±344, IL-p-n: 1777±356, C-l-b: 1537±324, C-p-b: 1865±369, C-l-n: 1341±247, and C-p-n: 1449±194. When comparing only veneering technique with all metal and layering system data combined, no statistical difference (ANOVA (p≤0.05)) was seen between the powder build up and press techniques.

Conclusion: Within this study, there is no significant difference in failure load of the veneering material between layering and pressable techniques of two commercially available systems on two types of metals.