Saudi Endodontic Journal

: 2021  |  Volume : 11  |  Issue : 1  |  Page : 100--103

Chloroform skin injury after endodontic Chloroform skin injury after endodontic retreatment: Case report

Sarah Mubarak Alkahtany 
 Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh, Saudi Arabia

Correspondence Address:
Dr. Sarah Mubarak Alkahtany
Department of Restorative Dental Science, College of Dentistry, King Saud University, PO Box 68004, Riyadh 11527
Saudi Arabia


A nonsurgical root canal retreatment was initiated for the upper right second premolar in a 35-year-old healthy female patient as part of her comprehensive dental treatment. She reported severe pain during the treatment, and then the procedure was discontinued due to time limitations. The next day, she returned back to the clinic complaining of a skin injury on the right side of her face. According to the patient's history, she felt a burning sensation during the procedure when the treating clinician began using a solution from a syringe. Extraoral clinical examination revealed a dry, pink-brown skin injury extending from the right labial commissure to the middle cheek area. Since the only solution used during the first visit was chloroform, the skin injury was diagnosed as a first-degree chemical burn due to accidental chloroform skin exposure. The patient was reassured and instructed to use petroleum jelly (Vaseline) until healing was complete. After 2 weeks, the burn had healed completely without scarring, with only slight hyperpigmentation remaining in the affected area. Chloroform use should be limited to cases in which mechanical gutta-percha removal is ineffective. It should be handled with extreme caution. Chemical burns can be prevented if exposure is detected immediately and the area washed thoroughly. This clinical case is made to increase the clinicians' awareness of the hazards of chloroform.

How to cite this article:
Alkahtany SM. Chloroform skin injury after endodontic Chloroform skin injury after endodontic retreatment: Case report.Saudi Endod J 2021;11:100-103

How to cite this URL:
Alkahtany SM. Chloroform skin injury after endodontic Chloroform skin injury after endodontic retreatment: Case report. Saudi Endod J [serial online] 2021 [cited 2021 May 6 ];11:100-103
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Full Text


Chloroform, or trichloromethane, is a clear, colorless, and volatile liquid with an ether-like odor. It was considered an anesthetic agent until it was found to cause death. Currently, it is used in the pesticides and rubber industries, mainly as a solvent for oils, rubber, waxes, resins, and gutta-percha (GP).[1]

Root canal treatment failure is often associated with insufficient cleaning of the root canal system.[2] Nonsurgical root canal retreatment is indicated for those cases. During the retreatment procedure, the clinician must remove the GP thoroughly from the root canal space to enable adequate cleaning and shaping.[3] Different GP removal techniques have been proposed, including the use of chemical solvents such as chloroform, heat, or mechanical removal with Hedstrom stainless steel files and retreatment nickel–titanium rotary files.[4],[5],[6] Chloroform was reported to be the most effective solvent for GP removal.[7] Despite its potential side effects, chloroform is still used in the dental office. While most published guidelines highlight the side effects of accidents involving sodium hypochlorite,[8] the risks associated with chloroform use are not commonly mentioned.[9]

To increase clinicians' awareness about the hazards of chloroform, a clinical case report is presented regarding an accidental chloroform skin injury following the use of chloroform during nonsurgical root canal retreatment performed by a dental student.

 Case Report

A 35-year-old female, unaware of any medical problems, was assigned to a 5th-year dental student in the comprehensive clinical course. Her upper right second premolar (tooth #15) had a previous root canal treatment with symptomatic apical periodontitis [Figure 1]. After examination, a nonsurgical root canal retreatment and full crown were decided for that tooth as part of a comprehensive treatment plan. The patient was informed about the plan and signed a consent form.

Buccal infiltration local anesthesia was given using 2% xylocaine with adrenaline 1:80,000 (Dentsply Sirona, USA). Previous restoration removal, caries excavation, and access cavity preparation were performed for tooth #15 under rubber dam isolation. The GP was removed completely with stainless steel hand files and chloroform in a 1 ml syringe and 26-G needle, and the patient began to feel severe pain. Due to time constraints, the procedure was discontinued, and a Cavit (3M, Germany) temporary restoration was placed. No medication or instructions were given to the patient. The student thought the pain was due to wearing off local anesthesia effect!!{Figure 1}

The next day, the patient returned to the clinic complaining of a skin injury on the right side of her face [Figure 2]a. The dental student was unaware of the cause of the skin injury. An endodontist examined the patient, and a consultation was performed with an oral medicine specialist. Extraoral clinical examination revealed a dry, pink-brown skin injury extending from the right labial commissure to the middle cheek area. Intraorally, the gingiva and oral mucosa were found to be intact with normal color. According to the patient's history, she felt a burning sensation during the root canal retreatment when the treating clinician started using a solution from a syringe.{Figure 2}

The skin injury was diagnosed as a first-degree chemical burn from chloroform use [Figure 2]b. The patient was reassured and instructed to use petroleum jelly (Vaseline) on the affected skin. After 2 weeks, root canal retreatment was completed, and fiber post was cemented [Figure 3]. At that time, complete healing of the skin injury was observed without any scarring [Figure 4]a. Only slight hyperpigmentation was visible in the affected area after 4 months [Figure 4]b.{Figure 3}{Figure 4}


During an endodontic retreatment procedure, accidental errors can occur, including broken instrument, root perforation, oral or dermal exposure to chloroform.[3],[9] Chloroform is rapidly absorbed and metabolized in the tissues by CYP2E1, a member of the cytochrome P450 enzyme.[1] The cytotoxicity of chloroform has been attributed to phosgene, a toxic byproduct that results from chloroform metabolism. Phosgene can bind to cell proteins, leading to a loss of cell function and cell death.[10] Torkelson et al. reported that 24-h application of chloroform to the rabbit skin can induce slight to moderate irritation and delayed healing.[11] According to the available evidence, chloroform does not have significant genotoxic potential. However, it has been classified as possible human carcinogen.[1],[12]

First-degree burns are limited to the outer layer of the skin and the epidermis.[13] They are painful, dry, pink, or red skin lesions, without blisters. According to the literature, superficial burns heal without scarring within 5–14 days.[14] In the current case, the patient was diagnosed with a first-degree facial chemical burn on her right cheek caused by chloroform exposure; it took 2 weeks for the injury to heal completely without scarring. In a 4-month follow-up visit, the affected skin was slightly pigmented due to stimulation of melanocytes during the healing process. With time, this hyperpigmentation will return to the normal skin color.[15]

The present case is considered the only data in dental literature reporting accidental extraoral injury due to chloroform exposure. Previous publications about chloroform accidents reported only intraoral injuries. Verma et al. reported an accident in which the treating clinician injected a chloroform solution instead of local anesthesia that resulted in soft-tissue necrosis and permanent nerve damage.[16] Mohammadzadeh Akhlaghi et al. reported a case of accidental chloroform extrusion through undetected root perforation during nonsurgical retreatment that caused gingival and alveolar bone necrosis.[9] In the current case, the gingiva and oral mucosa were intact with a completely normal appearance. Therefore, we excluded the possibility of chloroform apical extrusion or a leaking rubber dam as the cause of the skin injury. The most likely cause of this injury was chloroform drops from the syringe on the patient's skin or the rubber dam napkin. Clinicians with little experience are not yet adept at perfectly controlling the solution flow from a syringe. When the clinician exerts force on the relatively small plunger, the intra-barrel pressure will increase to become higher than the pressure at the needle tip, leading to fluid flow. During the first few seconds of dispensing a solution from the syringe, there is a rapid increase in pressure due to a delay in the clinician's coordination of the exerted force. Therefore, the flow of the solution will continue, even without any force, due to the previous pressure.[17]

The details of the current case led us to recommend extra caution during the use of chloroform. If mechanical GP removal is ineffective and a solvent is needed, only a limited amount of chloroform should be used inside the root canal under rubber dam isolation, and apical extrusion should be avoided.[18] Moreover, we recommend handling the syringe with care and releasing the pressure of the chloroform syringe away from the patient to avoid accidentally dispensing the chloroform on the patient's skin or eyes. The use of suction is mandatory whenever a solution is dispensed; this will aid in avoiding mucosal or skin exposure.

Unfortunately, the present case was not managed properly because the patient's symptoms and the accidental chloroform skin exposure were not recognized early. The side effects of chloroform could be prevented or minimized, if the accidental chloroform exposure been detected and the affected area washed immediately.[1] The patient's safety is our responsibility; we must always be vigilant for all patient reactions and complaints to prevent or properly manage any potential injury during clinical procedures.


Chloroform in a dental clinic must be handled with extra caution to prevent accidental chloroform skin exposure. Chemical burns can be prevented if the exposure is detected early and the exposed area washed immediately.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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