Paraformaldehyde has been used in endodontics when effective anaesthesia could not be achieved. However, this agent has many adverse effects including gingival, bone necrosis, osteomyelitis and allergy on account of systemic exposure. Therefore, the use of pastes containing paraformaldehyde should be avoided in contemporary dental practice.

The aim of this case report was to present the application of platelet-rich fibrin(PRF) in combination with a coronally advanced flap in the treatment of gingival and bone necrosis associated with paraformaldehyde containing devitalizing paste toxicity. PRF is an autogenous resorbable membrane composed of platelets, cytokines, leukocytes and growth factors.

Results and conclusions:
Four weeks following burgery, the wound was completely healed with epithelial cells covering the interdental crater. On the basis of literature and of the present case, it can be stated that the use of PRF significantly reduces postoperative pain and promotes tissue healing.

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