What is the primary advantage of achieving straight-line access in endodontic access cavity preparation?

Straight-line access means that endodontic files can be directed from the access opening to the apical foramen without deflection by coronal tooth structure or canal curvature above the canal orifice. Achieving straight-line access: reduces instrument separation by minimizing stress concentrations, improves tactile sensation for working length determination, facilitates placement of irrigation needles to the working length, and reduces the risk of ledging, transportation, or procedural errors. It is achieved by removing dentinal triangles and other obstructions that would deflect instruments from a direct path to the apex.