Ultraviolet radiation is a type of Electromagnetic radiation which ranges between the wavelength of 100 and 400nm and are divided into three types based on their wavelength. When exposed to UV radiation even for a short duration of time can cause harmful effects, hence it is very important to make sure that proper care is taken while using UVC for Sterilization procedure in Dental Clinics. As the UV lamps or tube lights produce light radiation from ultraviolet through visible to infrared radiation, UV Radiation is the biggest hazard as it cannot be felt immediately on exposure for both skin and eyes. Usually Symptoms due to UV exposure is felt after 4 to 24 hours after exposure in Acute cases. 

In the times like this, with the ongoing COVID-19 pandemic Sterilization takes up utmost importance in Dental Clinic set-up to give peace of mind to work for the Dental staff. With Coronavirus spread through aerosols it is very important to maintain a sterilized environment to prevent spread of the disease from patient to Dental staff and the other way around as well. 

What are the types of UV Lamps used and which types are used for Sterilization in Dental Clinics or Hospitals?

Ultraviolet Radiation ranges from 100nm to 400nm and the UV spectrum is divided into three types based on its wavelength. 

  • UV-A: It ranges between 315 to 400 nm
  • UV-B: It ranges between 280 to 315 nm
  • UV-C: It ranges between 100-280 nm

The UV radiation produced by Sun which reaches the earth falls under the wavelengths of UV-A, as the harmful UV-B and UV-C spectrum are filtered out by the earths atmosphere protecting us from the harmful effects of UV radiation.  Commonly used spectrum in Dental clinics and hospitals for sterilization are the UV-B and UV-C types. 

Safety Tips for using UV Sterilization in Dental Clinic

Effect of Ultraviolet radiation on Skin and Eyes:

Ultraviolet radiation effect on the body even in short duration is harmful, which depends on many factors such as the the intensity of radiation, time for which you were exposed, wavelength of radiation and sensitivity of the individual. It has been proven in many studies showing a direct connection between skin cancer and exposure to UV radiation below the range of 320nm which include UVB and UVC types. UV radiation is neither visible not felt on the skin or eyes immediately, as symptoms can start from 4 to 24 hours. 

Effect of UV radiation on Skin: It effects the skin in two types based on the time in which the symptoms appear – It is termed Acute where the effects are seen within few hours such as Erythema (sunburn) redness of skin which are not long lasting and reversed immediately. It is termed as Chronic when the symptoms do not appear for a few years and are usually long lasting such as skin aging or skin cancer. 

Effect of UV radiation on Eyes: It effects the outer layer of eyes (cornea and conjunctiva) in two ways, Acute – where the effects are seen within few hours and lead to painful temporary inflammation known as photokeratosis affecting the cornea. The Chronic effects on the Eyes lead to occular cataracts. 

UV radiation is harmful at what wavelengths: 

Ultraviolet light radiation is the most hazardous in wavelengths between 240 and 315nm which includes the UV-B and UV-C regions. 

Safety precautions needed against UV Sterilization:

To prevent any exposure to your Skin and Eyes from the UV radiation certain precautions need to be taken. 

  • Always evacuate the room before starting UVC sterilization 
  • Using either a timer or Bluetooth enabled device which lets you turn on the UV light after leaving the room being sterilized. 
  • Avoid looking at the UV light source directly
  • If you are in the room being sterilized, always wear protective eye wear and full hand sleeves and gloves to avoid any rays to touch your eyes or your skin. 
  • Always sterilize the working area after locking the door and its better to put up a warning sign at the entrance
  • UV tubes have been known to burst or break in case of mis-handling, always handle the tubes using a cloth or cotton gloves, make sure there are no scratches on the tube which can damage the integrity of the tube
  • Always dispose the Tube after it completes its set number of hours to be used. 

Personal Protection Equipment (PPE): It should include a Face Shield, Gloves, Lab coat.

UV absorbing Face Shield: UV absorbing full-face shields are needed to protect your complete face and neck which is not possible with goggles. 

Gloves: Tightly woven fabric gloves, latex and nitrile gloves are recommended as they protect against UV-B and UV-C type of radiation which is not possible by Vinyl gloves and hence are best avoided. 

Coat or Apron: A Fabric lab coat is best which covers till your wrist, neck without leaving any skin exposed.  

Hazard Warning Sings – 

  • High Intensity Ultraviolet Light inside, avoid Eye & Skin Exposure and wear proper Eye & Skin Protection.
  • High Intensity Ultraviolet Light inside, Turn Off UV Light before entering room.

It is very important to follow strict protocols while using UV light Sterilization due to the harmful effects of the UV radiation on the human body. As effective as it is in terms of sterilization it is harmful in the same sense, so taking precautions is the best way to keep yourself safe.