Fracture resistance of teeth restored with two different post-and-core designs cemented with two different cements: An in vitro study. Part I

Objective: The purpose of this in vitro study was to investigate fracture resistance in teeth restored with cast post and cores with and without ferrule and using two different luting cements. Method and materials: Forty intact maxillary premolars were endodontically treated after their crowns were removed at 2.00 mm from the cementoenamel junction. Specimens were embedded in acrylic resin blocks in aluminum cylinders, 4.00 mm apical to the cementoenamel junction. Twenty specimens were ferruled, and half of the posts and cores were cemented with zinc-phosphate cement, while the other half was cemented with resin cement. The same procedures were followed for the nonferruled group. Loads were applied at an angle of 45 degrees and measured with a universal testing machine. ANOVA and Tukey test were used for statistical analyses; a significance level was established at 5%. Results: Ferruled specimens showed greater resistance than nonferruled ones, regardless of the cement used. There was no statistical difference between the group of specimens cemented with resin cement and without ferrule and the ferruled groups. The nonferruled group with zinc-phosphate cement showed the poorest results. Conclusion: A 2.00-mm cervical ferrule is important for fracture resistance of restored teeth, and resin cement has a better performance.