Veneer Firing Effects on Zirconia


Creative Commons License

Aydoğdu H. M., Eskitaşçığlu M.

39th Annual Conference of the European Prosthodontic Association, Praha, Czech Republic, 3 - 05 September 2015, pp.52

  • Publication Type: Conference Paper / Summary Text
  • City: Praha
  • Country: Czech Republic
  • Page Numbers: pp.52
  • Çanakkale Onsekiz Mart University Affiliated: No

Abstract

Purpose

To observe dimensional changes during veneer firing on zirconia frameworks sintered with three different programs.

Materials and Methods

72 zirconia single crown frameworks were randomly assigned to three groups and sintered with three different programs with durations of 8 hours (A), 2 hours (B) and 10 minutes (C). A Toolmaker’s microscope was used to take marginal gap measurements from 36 equidistant points; also measurements to calculate  the projectional area and perimeter between four marked points on each occlusal and buccal surfaces were taken. All frameworks were subjected to 5 veneer firings without applying porcelain to observe the insulate effect of heat treatment. All dimensional and marginal gap measurements were repeated after veneer firings.

Results

Marginal gap values before and after veneer firings were 37,61μm-35,98μm for group A; 36,68μm-33,06μm for group B; 33,28μm-30,48μm for group C. The change in marginal gap was insignificant for group A, significant for groups B and C (p<0,05). The occlusal surface dimensional changes of groups A, B and C were -0.163%, -0.181%, -0.086% for perimeter and -0.321%, -0.300%, -0.197% for area respectively. Buccal surface dimensional changes of groups A, B and C were 0.178%, 0.144%, 0.257% for perimeter and 0.340%, 0.313%, 0.556% for area respectively. There is no significant difference between three groups regarding surface dimensions. (p>0.05).

Conclusions

Veneer firing caused shrinkage in occlusal surfaces and enlargement in buccal surfaces. Marginal gap values decreased after veneer firing in all groups.