Stress analysis of different experimental finite element models of rotary endodontic instruments

Abstract Aim The mechanical response was assessed through finite element analysis by comparing the cross-sectional impact of two rotary file mathematical models: CM wire and R-Phase. Methods New rotary file model designs were developed using computer-aided design software, specifically the SolidWorks package, along with finite element models. The files featured a triangular cross section at the tip, transitioning to either a rhomboid or rectangular cross section with eccentricity. Each model was subjected to cantilever bending and torsional stress analysis. Results The analysis revealed that the maximum stress values were highest for the rectangular cross section (R-phase), followed by the rectangular cross section (CM wire), then the rhomboid cross section (R-phase), with the lowest values associated with the rhomboid cross section (CM wire). In terms of maximum torsional stress, the rectangular cross section (R-phase) again exhibited the highest values, followed by the rectangular cross section (CM), rhomboid cross section (R-phase), and lastly, the rhomboid cross section (CM). These results support clinical recommendations to use files with a triangular-shaped tip and eccentric cross sections to minimize the risk of ledging, thereby enhancing clinical performance by reducing screw-in forces. Additionally, the rectangular cross-section file model demonstrated greater displacement compared to the rhomboid cross-section model. Nevertheless, the rhomboid cross section exhibited superior torsional resistance relative to the rectangular model. Conclusion It was highlighted that both bending and torsional resistance are critical factors to consider when designing file models. Detailed reporting and clear illustration of test results under these loading conditions are crucial for guiding future design improvements and ensuring optimal performance in clinical settings. This attention to detail will help in developing file models that enhance mechanical properties while minimizing risks during use.