This work is licensed under Creative Commons Attribution–NonCommercial International License
(CC BY-NC 4.0).
Background: This study evaluated the fracture resistance and fracture modes of endodontically treated maxillary
premolars restored with different composite resins, focusing on the effect of fiber reinforcement.Stunting is defined
as short stature for the age group, with a Z score less than −2 SD (standard deviation).
Materials and Methods: Sixty extracted maxillary first premolars were divided into six groups (n=10): intact
control, conventional nanohybrid, bulk-fill (SDR), short-fiber-reinforced (EverX Posterior and EverX Flow), and
Ribbond fiber. After standardized endodontic treatment and MOD cavity preparation, restorations were placed per the
manufacturer’s instructions. Specimens were loaded to fracture under compressive force using a universal testing
machine. Data were analyzed by one-way ANOVA and Fisher’s LSD test (p<0.05), and fracture modes were examined
under magnification.
Results:Significant differences were found among groups (p < 0.0001). Intact teeth showed the highest fracture
resistance (1047 ± 170 N). Among restorative materials, EverX Posterior achieved the greatest strength (624 ± 138
N), followed by EverX Flow (550 ± 80 N), Ribbond (548 ± 94 N), SDR (491 ± 119 N), and conventional composite
(401 ± 76 N). EverX Posterior outperformed SDR (p = 0.014) and conventional composite (p = 0.001). Restorable
fractures occurred mainly in intact teeth (80%) and EverX Flow (40%), with minimal repairable outcomes in other
groups.
Conclusion: Fiber-reinforced composites notably improved fracture resistance compared with bulk-fill and
conventional composites. EverX Posterior exhibited the highest reinforcement capability, whereas conventional
composites showed the weakest performance. However, fiber reinforcement did not always yield more favorable
(restorable) fracture patterns.