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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

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Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Publicly available literature without indication of guideline and GLP

Data source

Reference Type:

Materials and methods

Study type:
human medical data
Endpoint addressed:
not applicable
Test guideline
no guideline followed
Principles of method if other than guideline:
Public available literature. No guideline indicated. For details on method see materials and methods section in IUCLID5 dossier (case report).
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium hypochlorite
EC Number:
EC Name:
Sodium hypochlorite
Cas Number:
Molecular formula:
sodium hypochlorite
Details on test material:
Sodium hypochlorite solution is available in commercial bleaches such as Purex and Clorox with average pH of 10.83-10.98 and a chemical composition as follows:• Sodium hypochlorite5.25 %• Sodium carbonate0.20 %• Sodium chloride4.00 %• Free sodium hydroxide0.0005-0.015 %• Water90.00 %


Type of population:
other: patient
Ethical approval:
not applicable
Details on study design:
Persons exposedSex: femaleAge/weight: 23-year-old, weight not indicatedKnown Diseases: allergy to penicillin; deep caries at the mesial aspect of the maxillary right cuspidNumber of persons: 1 This case report relates the accidental injection of sodium hypochlorite through the root canal into the periapical tissues. The case happened at the School of Dentistry of the University of the Pacific, San Francisco, California, USA. The patient had a medical history of allergy to penicillin. Roentgenograms showed deep caries on the mesial aspect of the maxillary right cuspid, the periapical tissues appeared to be normal.A pin-retained composite build-up of the tooth was made and endodontic access was obtained. A pulpectomy was performed. The canal was instrumented to a size No. 45 and medicated with metacresylacetate and sealed with Cavit (Premier Co., Philadelphia, Pa, USA). The following day the root canal was irrigated between instruments with a 5.25 % solution of sodium hypochlorite until the canal was enlarged to a size No. 70. After the final instrumentation, a 25-gauge needle attached to a 10 mL Luer-Lok disposable syringe was inadvertenly wedged in the canal, and approximately 0.5 mL of sodium hypochlorite was forced beyond the apex into the periapical tissues.ExposureReason of exposure: Accidental injectionFrequency of exposure: SingleExposure concentration/dose: Appoximately 0.5 mL of sodium hypochlorite solutionExaminationsTreatment: Therapy measures following accident:- palliative therapy was immediately instituted- elevation of dental chair and cold compresses- medication: two 4 mg tablets of Dimetane, two 325 mg tablets of Tylenol, two 250 mg tablets of tetracycline HCl given orally and instruction for further Dimetane, tetracycline and aspirin or Tylenol intakeAt the pH of 10.83-10.98 the mechanism of injury from undiluted liquid chlorine bleach is primarily oxidation of proteins. The degree of destruction when sodium hypochlorite comes in direct contact with healthy soft tissues is determined by the duration of the contact and the concentration of the sodium hypochlorite.

Results and discussion

Clinical SignsReactions to accidental treatment:- immediate extreme pain (radiated from the right side of the nose in the area of the angular artery and vein, along the side of the face superficial to the parotid gland to the ear, and inferior to the mandible into the area of the gonion)- signs of edema of right cheek and upper lid within 30 seconds- profuse haemorrhaging through the canal, ceased 6 minutes after the accidental injection- rate of aspiration slightly faster- swelling of the face extended slightly to the eye and was more noticeable in the subzygomal areas of the lip and cheek - after 24 h: swollen lips, right eye swollen shut, slight ecchymosis under the left orbit and diffuse ecchymosis over the right side of the face- after 1 week: most of the swelling subsided, lower and upper eyelid had an ecchymotic appearance- after 2 weeks: no swelling, moderate hemosiderin staining- after 1 month: face returned to normalResults of examinationsThe clinical signs observed in this case report can be directly attributed to both the irrigant and the irrigating technique. Total recovery of the patient from clinical signs was reached within one month. In view of the known irritant and corrosive properties of sodium hypochlorite, the effects reported in humans suggest an irritation rather than a sensitizing potential. For prevention of similar cases the author of this study recommends to assure that the needle is not locked in the canal and the irrigant is expressed slowly.

Applicant's summary and conclusion

Sodium hypochlorite accidentally injected beyond root apex causes severe pain, edema and swellings.
Executive summary:
In this case report the sequelae of accidently injecting sodium hypochlorite beyond the root apex of a 23-year-old white woman is described. The accident happened at irrigation of the root canal because the syringe was inadvertenly wedged in the canal and sodium hypochlorite was expressed into periapical tissues. Immediately instituted therapy measures included cold compresses and administration of Dimetane, Tylenol and tetracycline. Clinical signs as reaction to the accidental treatment were mainly severe pain, edema and eye and face swelling. In view of the known irritant and corrosive properties of sodium hypochlorite, the effects reported in humans suggest an irritation rather than a sensitizing potential. Total recovery applying the described therapy measures was achieved within one month. For prevention of similar cases the author of this study recommends to assure that the needle is not locked in the canal and the irrigant is expressed slowly.