Robert J. Hanlon, Jr. DMD
Charles E. Jerome, DDS
Safe use of Sodium Hypochlorite as an Irrigant


The use of sodium hypochlorite (NaOCl) also known as 5.25% Clorox bleach is an important element in contemporary endodontic treatment. Combined with the mandatory use of a rubber dam, full strength NaOCl can be the most critical element in successful endodontic therapy.

There is an overwhelming amount of clinical research reporting that NaOCl is required to dissolve tissue contained in microscopic spaces.  5.25% NaOCl is very basic (pH 12.02) and very toxic.

Inadvertent extrusion (sodium hypochlorite accident) of NaOCl through the apex of the tooth and into the surrounding tissues can have dramatic inflammatory consequences and must be avoided.  In the month of March, we had two calls from general dentists concerning sodium hypochlorite accidents.

The two most common causes of an accident are (1) excessive pressure during irrigation and (2) wedging the irrigation needle in the canal.

Contraindications for NaOCl use:

·         Pediatric teeth, both deciduous and young permanent teeth with open apices

·         Roots with obvious large radiographic external resorptive defects

·         Roots of maxillary molars with open apices in close proximity to the sinus

Recognizing an accident

·         If the patient complains of pain during an endodontic procedure and you are using NaOCl but not actively instrumenting the tooth, immediately dilute the canals and investigate.

·         If any rapid swelling or tissue discoloration occurs, immediately stop and remove the NaOCl.

Avoiding an accident

·         Use only Luer Lock needles that are side vented or Vista Probe and Max-I-Probe type needles that are closed ended with side-port delivery. Deliver the NaOCl with a stirring and pumping type motion.  Keep the syringe in motion to prevent it from wedging in the canal.


·         Treatment will be palliative and protective because NaOCl cannot be drained

·         Immediately irrigate the canal with sterile saline to dilute the NaOCl

·         Stop treatment and immediately explain to the patient what is happening

·         Inject a long acting anesthetic but in an area remote or posterior to the treated tooth

·         Prescribe a strong narcotic analgesic for pain control, ice the first day, heat the following days

·         Appropriate antibiotics: Penicillin, Cleocin if allergic, place a drain for 3-5 days

·         Follow the patient daily and , if possible, photo document with patient consent

An excellent alternative for NaOCl is 0.12% chlorhexidine (Peridex). Although it has no tissue dissolution property, it will provide substantive anti-bacterial activity. Research is currently being conducted on an endodontic irrigant that may revolutionize the way we attempt to sterilize canals.

Use the time that you save instrumenting the tooth and “invest” in soaking the spaces with NaOCl for maximum tissue dissolution. Remember: vital – dense collagenous connective tissue takes longer to dissolve than necrotic tissue. Follow the guidelines for the safe use of NaOCl and be confident that your cases are cleaner and prepared for a successful outcome. Please do not hesitate to call us or refer patients for evaluation if you have problems with sodium hypochlorite.



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