Severe tissue necrosis following intra-arterial injection of endodontic calcium hydroxide: a case series.

We present 2 cases of intra-arterial injection of endodontic calcium hydroxide via the root canal system of molar teeth. Nonsetting calcium hydroxide paste was used as a temporary dressing during endodontic treatment and in both cases delivered via an injectable syringe technique. Retrograde flow of the calcium hydroxide occurred along the artery until its origin where orthograde flow continued to the capillary bed. Case 1 demonstrates calcium hydroxide injected into the distal root canal of a lower second molar resulting in its distribution to the external carotid bed and case 2 demonstrates calcium hydroxide injected into the palatal root of an upper second molar with flow into the infraorbital artery. In both cases this resulted in severe clinical signs and symptoms ending in tissue necrosis. Long-term sequelae included scarring, deformity, and chronic pain. This case series illustrates the high toxicity of calcium hydroxide when displaced into vessels and soft tissues. Caution should be exercised when using injectable systems for endodontic calcium hydroxide.