Sodium Hypochlorite Accident during Canal Treatment: Report of Four Cases Documented According to New Standards

Hypochlorite accidents are relatively rare events. Therefore, there is a lack of precise and accurate reports in the scientific literature that could help clinicians better understand the phenomenon and associated risk factors. This study reported four hypochlorite accidents attributable to 5% NaOCl extrusion in patients who had undergone treatment of the maxillary elements canal treatments. In all cases, the accidents occurred during the irrigation phase and were characterised by intracanal bleeding, ecchymosis, and swelling on the hemiface corresponding to the treated tooth. Antibiotics, paracetamol, NSAID, corticosteroids, and cold or warm compresses for oedema were prescribed to treat the symptoms of the accidents. Significant improvement of symptoms was observed in all patients after 5–6 days. Anatomic risk factors such as apical fenestration, root perforation, and large foramina were identified as possible risk factors for the accidents. After the accidents, clinicians applied endodontic procedures for which there is no scientific evidence to continue endodontic treatments, such as changing the type of irrigant or the irrigation method. Our results suggest that using a standardised approach to document each hypochlorite accident will allow researchers to collect more accurate and detailed data that can subsequently be used to identify potential risk factors and better manage the symptomatology of hypochlorite accidents.