The dreaded spill: hypochlorite incident in dentistry

HypochloriteHasan Zishan explores some of the problems with using hypochlorite during endodontic treatment and what the alternatives are.

Endodontics is daunting at the best of times. Many of us are guilty of shying away from endodontics, letting potential risks get in the way of us improving our skills.

We have all seen clinical photos of patients who have bruising and swelling from a hypochlorite incident. This is a stressful situation.

Knowing how to reduce the chances of this and understanding appropriate management can therefore help to increase confidence in carrying out endodontic treatment.

What is hypochlorite?

Sodium hypochlorite, better known as bleach, is routinely and regularly used in endodontic treatment as an irrigant.

Why do we use it?

  1. To reduce or eliminate pulpal remnants
  2. To reduce or eliminate bacterial remnants – the major cause of pulpal and peri-radicular pathosis.

Added benefits include:

  • Haemorrhage control of bleeding pulps
  • Reduces friction when using files by providing canal lubrication
  • Cooling effect on the file
  • Improves visualisation by removing debris.

Are there any alternatives?

Manual cleaning alone is insufficient due to the complexity of the root canal space.

  • Chlorohexidine – whilst bacteria is killed, chlorohexidine does not break down pulpal tissue or the smear layer as it does not dissolve organic matter. This residual matter will then reduce the quality of the seal of the permanent root filling
  • Water and saline – this is not great as the main irrigant due to a lack of tissue dissolving and microbial activity
  • EDTA – a useful irrigant in endodontics. Mainly for removing the smear layer, which is packed with microbes and microbial antigens. However, it has little to no antimicrobial activity itself.

Ultimately, sodium hypochlorite is considered the gold standard irrigant solution in endodontic treatment. Despite being cytoxic, its benefits outweigh its risks if used in a safe way.

How to safely use sodium hypochlorite

  • Protecting the patient, yourself and your team is paramount. Wear correct PPE at all times. Including an apron to protect the patient’s clothes from spillage
  • Well fitted patient safety googles (not their own glasses)
  • Use a well-sealed rubber dam, along with caulking agent if necessary
  • Clearly mark and don’t overload syringes and any cups with hypochlorite
  • A side venting delivery needle to prevent hypochlroite being forced through the apex
  • Bend the needle 2-4 mm short of the working length to prevent high pressure at the apex. Bleach will be introduced into the apical portion of the canal with a K file
  • Assistant should use high volume suction as close to the tooth as possible
  • Use light force, with pressure on the plunger applied by the index finger
  • Slow delivery of irrigant
  • Do not use in perforations or open apex
  • The patient should report any strange taste during the procedure
  • Place a cotton pledget/guaze near the access to soak up any spillages
  • Heat and activate the bleach manually, with an ultrasonic or with sonic activation. This increases its efficacy, which is especially useful if you want to use lower concentrations of sodium hypochlorite
  • Use a COSHH-approved medical grade hypochlorite such as Parsans. The DDU advise the following: ‘We are not aware of any national guidance on this or on the best concentration of sodium hypochlorite to use for irrigation. However, from a practical viewpoint, it’s worth considering the potential difficulties of justifying the use of household bleach bought from a supermarket to a non-dentist, such as a judge or a lay member of a GDC fitness to practise panel, especially if it has caused harm to the patient.’
Figure 1: Side vented needle bent 2-4mm short of working length. You can also use a rubber stop to ensure the right length
Figure 2: Use of the index finger to control pressure

When things go wrong, how do we manage the situation?

No standard therapy for managing complications is documented or widely accepted. This is likely due to the incident being so rare and sporadic.

The following is a non exhaustive list of management that can benefit the patient.

If an oral spillage occurs

  • Remove the rubber dam frame and get the patent to rinse out with copious amounts of water. Discourage vomiting as this can further damage the oesophagus
  • When the patient is stable, dress the tooth to prevent bacteria entering the canal space.

Spillage into the eye

  • Make sure you use good fitting goggles at all times
  • Rinse the eye out with water or saline for 15 minutes.

Spillage through the apex

  • Common signs include sudden burning pain, swelling and bruising. Bleeding from the canal may also be seen
  • Provide long acting local anaesthetic for pain relief
  • Flush canal with water or saline to dilute the hypochlorite
  • Tell the patient what has happened and reassure them
  • Post-operative instructions for the patient such as advising them to apply a cold compress every 15 minutes for 24 hours, then a warm compress
  • Prescribe antibiotics to prevent any secondary infection. Amoxicillin 250 mg tds or Metronidazole 200 mg tds in the penicillin allergic patient
  • Contact patient’s GP to prescribe analgesics to manage pain. Advise NSAIDS – adult doses of paracetamol 1 g qds and ibuprofen or ibuprofen 400 mg qds can be used alternately at four-hourly intervals if necessary
  • Call and arrange regular appointments, until it is appropriate to complete the treatment
  • Record accurate clinical notes as well as reporting any incidences in the practice log book
  • Assess airways, breathing and swallowing in all swelling cases. It may also be advisable to seek advice from an emergency department
  • Manage any injuries resulting in significant swellings, ulceration or necrosis in secondary care. You can seek advice from a max fax department.

Inhalation and ingestion are rare occurrences in dentistry.

Figure 3: Facial asymmetry due to swelling and well delineated area of erythema

The future

The issues with sodium hypochlorite is leading to a number of interesting new products.

These products are based on stabilised hypochlorous and this has been shown to kill 99.9999% of harmful organisms before, during and after treatment. Whilst it is also bio compatible and non toxic. Clinicians are currently researching the product as an alternative to sodium hypochlorite but it is too early to be sure.

Further reading

Farook S, Shah V, Lenouvel D, Sheikh O, Sadiq Z, Cascarini L and Webb R (2014) Guidelines for management of sodium hypochlorite extrusion injuries. Br Dent J 217: 679-84

Mohammadi Z (2008) Sodium hypochlorite in endodontics: an update review. Int Dent J 58(6): 329-41

Spencer HR, Ike V and Brennan P (2007) Review: the use of sodium hypochlorite in endodontics — potential complications and their management. Br Dent J 202(9): 555-9

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