File Breakage in Conventional Versus Contracted Endodontic Cavities.

Objective: To compare rotations to failure and tip separation length of a nickel-titanium (Ni-Ti) rotary in- strument within a simulated mesio-buccal canal of a mandibular molar with a conventional or contracted endodontic cavity.

Methods: Two identical lithium disilicate #30 crowns were milled. A conventional or contracted endodontic cavity was prepared.