Comparison of Fracture Resistance of Endodontically Retreated Mandibular Premolar Roots using Two Obturation Techniques with Two Types of Sealers: An In Vitro Study

Objective: This study aimed to evaluate the fracture resistance of endodontically retreated roots after obturation using two obturation techniques with two types of sealers. Methods: Eighty extracted single-rooted lower premolars with single-oval canals were selected for the study. After decoronation, the canals were instrumented with ProTaper Next rotary files and randomly split into two main groups according to the obturation techniques: Group A (n=40) Cold Lateral Condensation obturation techniques (CLC) and Group B (n=40) Warm Vertical Compaction obturation technique (WVC). Then, the main groups were divided into two subgroups according to different sealers: Subgroup A1: (n=20) using gutta-percha with AH Plus sealer, Subgroup A2: (n=20) using gutta-percha with MTA Fillapex sealer, Subgroup B1: (n=20) using gutta-percha with AH Plus sealer, Subgroup B2: (n=20) using gutta-percha with MTA Fillapex sealer. All the root canal fillings were removed using XP endodontic retreatment files for retreatments. A universal testing machine was used for the fracture resistance test. The data were evaluated statistically by using analysis of variance (one-way ANOVA) (P < 0.05). Results: Cold lateral condensation with AH Plus sealer showed the highest mean fracture resistance (984 N). Meanwhile, WVC with AH Plus sealer showed the lowest fracture resistance (879 N). Statistical analyses showed a non-significant difference between all tested groups (P > 0.05). Conclusions: The highest fracture resistance was offered by CLC with AH Plus sealer. However, WVC using gutta-percha with AH Plus sealer resulted in the greatest decrease in fracture resistance compared to the other groups.