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Practical How To: How do you clean your light curing unit?

This post was prepared in collaboration with BlueLight Analytics

On an experimental basis, we have asked a limited number of companies to provide us with practical “How To” answers to clinical questions. We were prompted to conduct this experiment when dental team members told us that they visit company websites and consult company representatives for practical clinical information. We look forward to receiving your feedback on this experiment. 

Please refer to your specific Light Curing Unit (LCU) “Directions for Use” to find the curing light maintenance and care instructions.

If maintenance instructions have not been provided or are not accessible for the LCU, refer to the following guidelines based on instructions from the major dental LCU manufacturers.

Several studies researching the condition and use of curing lights in private practice have identified the need for clinicians to regularly care for and maintain their curing lights (1, 2, 3). This practical “How-To” article is provided as a resource to dentists and their teams on the essentials of maintaining their curing lights and these steps are of paramount importance as the condition of the curing light and its appropriate use greatly affect the longevity of resin composite restorations. In Canada, CDSPI has made it essential that curing lights be regularly maintained and tested to protect clinicians against malpractice claims (4).

Cleaning the light guide or fixed light tips

  • Clean, disinfect and sterilize the light guide before every use
  • Use an infection control barrier

Light Curing table


Cleaning Light Guides

Light GuidesClean and disinfect before every use. Always use single use infection control barrier/sleeve.

STEP 1 – Remove gross contamination from the light guide after using (max 2 hrs).

STEP 2 – Rinse the light guide off thoroughly (~ 10s) under running water or use a suitable disinfectant solution without aldehyde.

STEP 3 – Use a soft brush/cloth to manually remove contaminants.  Any composite adhered to the light should be removed, alcohol, and/or a plastic spatula may help in removing the material.  Do NOT use any sharp or pointed tools that may scratch the surface of the light guide.

STEP 4 – Place the light guide for the specified application time into the solution, ensuring it is completely covered.  (As required, use ultrasonic support or careful brushing with a soft brush.)  A neutral enzymatic cleaning agent is recommended (e.g. Cidezyme/Enzol – J&J).

STEP 5 – Remove the light guide from the solution and rinse thoroughly (~10s) in regular tap water.

STEP 6 – To disinfect, place the cleaned light guide for the specified application time into the solution, ensuring it is completely covered. Disinfectants containing o-phthalaldehyde are recommended (e. g. Cidex OPA – Johnson & Johnson).

STEP 7 – Remove the light guide from the solution and rinse thoroughly (~10s) in regular tap water.

STEP 8 – Dry the light guide with a clean cloth and check for damaged surfaces, discoloration and/or contamination.  If the light guide is still contaminated, repeat the cleaning and disinfection.  Do not use damaged light guides.

(Damaged light guides require replacement; however, damaged fixed light tips will require replacement of the light.)

STEP 9 – Cleaning and disinfection are essential for effective sterilization.  ONLY steam sterilization is approved. 

(If an infection control barrier has been used, autoclaving is not required.)


  • Maximum sterilization temperature 134 °C (273 °F)
  • Light guides must be sterilized before each use (unless disposable protective barriers/sleeves are used)
  • Autoclaving light guides reduces light output (Reference)

Cleaning Fixed Light Tips

Fixed Light TipsClean and disinfect before every use. Always use single use infection control barrier/sleeve.

Do NOT submerse in liquids or allow any liquid or other foreign substance to enter the handpiece.
Do NOT steam sterilize fixed light tips.
Do NOT clean or disinfect with highly aggressive agents. (See Table above)


STEP 1 – Immediately after use, remove sleeve taking care not to contaminate device.

STEP 2 – Use clean examination gloves. If the device is visually contaminated, clean the device with a detergent compatible to the disinfectant solution.  After cleaning, wipe the device with a cloth soaked with water to remove instrument detergent and dry with a clean, lint-free, single use cloth (eg. Kimiwipes or regular kitchen paper towels).

STEP 3 – Thoroughly wipe device using a single use cloth soaked with a bactericidal, virucidal, fungicidal alcohol-based instrument disinfectant solution approved according to local regulations and use according to instrument disinfectant manufacturer’s instructions for use. Pay special attention to device seams and insertions.

Cleaning the Charger, Handpiece, and Glare Shield 

Clean periodically or if the devices are visibly contaminated.

STEP 1 – Ensure all charging units are disconnected from the power outlet.

STEP 2 – Clean all components with a soft cloth and, if necessary, a mild cleaning agent (e.g. dish-washing detergent). Do not use solvents or abrasive cleaners which contain orange oil or ethanol content >40%.  Cleaning agents must not enter the unit.

STEP 3 To disinfect all components, spray the disinfectant on a towel and use it to disinfect the unit. Do not spray the disinfectant directly on the device. Disinfectant agents must not enter the unit.

STEP 4 – Dry residual disinfectants on the device with a soft and fluff-free cloth, as they can damage the plastic components. Clean the protective glass with a soft and fluff-free cloth. Beware of scratches.

Caution – Make sure that charge contact pins remain dry and are not contacted by metallic or greasy parts. Do not bend the charge contact pins during drying. Wet charge contact pins will cause an operating error.

LCU Damage

In case of damage, repair LCU if possible, or replace bulb, light guide or LCU.

Test Light Output  

Test LCU output regularly – all LCUs degrade with use.

Prior to each use  ensure that the LCU is in good working order.


  1. El-Mowafy O, El-Badrawy W, Lewis DW, Shokati B, Kermalli J, Soliman O, Encioiu A, Zawi R, Rajwani F. Intensity of quartz-tungsten-halogen light-curing units used in private practice in TorontoJ Am Dent Assoc 2005;136(6):766-773.
  2. Martin FE. A survey of the efficiency of visible light curing unitsJ Dent 1998;26(3):239-243.
  3. Miyazaki M, Hattori T, Ichiishi Y, Kondo M, Onose H, Moore BK. Evaluation of curing units used in private dental officesOper Dent 1998;23(2):50-54.
  4. Barghi N, Berry T, Hatton C. Evaluating intensity output of curing lights in private dental officesJ Am Dent Assoc 1994;125(7):992-996
  5. Malpractice and You, CDPSI 
  6. Al Shaafi (via this web link:  http://www.sciencedirect.com/science/article/pii/S2210815712000352)


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