Effect of restorative treatment with endocrown and ferrule on the mechanical behavior of anterior endodontically treated teeth: An in vitro analysis

Abstract

This study evaluated the effect of endocrown and ferrule restorative treatment on the mechanical behavior of anterior endodontically treated teeth. Human canines were treated endodontically and distributed in five groups (n = 10): sound teeth (S), crown associated with glass fiber post (GFP) and ferrule (GFP_f+) and that without ferrule (GFP_f-), and endocrown with ferrule (E_f+) and that without ferrule (E_f-). The crowns were obtained in lithium disilicate-based glass ceramic and cemented with resin. Thermomechanical loading (TL) was performed with progressive load of 80, 120, 160, 200, 240, 280, and 320 N with 20,000 cycles each, 140,000 cycles in total, frequency of 5 Hz, and temperature variation of 5°C-55 °C, followed by fracture resistance testing with load cell of 1000 Kgf and crosshead speed of 0.5 mm/min in a universal testing machine. Failure mode has been evaluated. Data were compared by Kaplan-Meier survival analysis (p < 0.05) for TL and one-way ANOVA and Tukey's test (p < 0.05) for fracture resistance. TL showed higher number of fractures for groups without ferrule (GFP_f- = 7, GFP_f+ = 3, E_f- = 10, and E_f+ = 2) and lower mean fracture load probability (GFP_f+ = 300 N, GFP_f- = 280 N, E_f+ = 320 N, E_f- = 188 N) than those with ferrule. Regarding fracture, teeth rehabilitated with GFP were more resistant to endocrowns with ferrule (p < 0.05). A higher percentage of type III failures after fatigue and type II failures after fracture were found. In conclusion, rehabilitation using GFP with ferrule is more favorable for anterior teeth, but the use of endocrown with ferrule proved feasible.

Keywords: Anterior endodontically treated teeth; CAD-CAM; Endocrown.