Influence of obturation technique and sealer type on the fracture resistance of maxillary central incisors with simulated traumatic fractures.

BACKGROUND: This study evaluated the effects of obturation technique and sealer type on the fracture resistance of endodontically treated maxillary central incisors with simulated traumatic crown fractures under clinically relevant loading conditions. METHODS: Forty extracted human maxillary central incisors were randomly assigned to either the single-cone technique or warm vertical compaction technique. Each group was further divided according to the sealer used: AH Plus or TotalFill BC. After obturation, the crowns were restored with a short fiber-reinforced composite and a nanohybrid composite resin. The specimens were stored at 100% humidity for two weeks and embedded in acrylic resin. Fracture resistance was assessed using a universal testing machine with oblique loading at 45°. The data were analyzed using two-way analysis of variance (ANOVA) at a significance level of 0.05. RESULTS: Both obturation technique and sealer type significantly affected fracture resistance. TotalFill BC produced higher fracture-load values than AH Plus, while the single-cone technique (SCT)/TotalFill BC group had the highest numerical mean. However, no significant interaction was found between obturation technique and sealer type. CONCLUSIONS: Within the limitations of this in vitro study, sealer selection emerged as the primary factor influencing fracture resistance. TotalFill BC provided greater fracture resistance than AH Plus across both obturation techniques, while the absence of a significant interaction indicated that neither technique conferred a sealer-specific advantage.