Steralization in Endodontics

Endodontics is an important branch of dentistry which deals with the Diagnosis, Prevention and Treatment of diseases concerned with the hard tissues(Enamel, dentin) and soft tissues(Pulp) of the tooth.

So for every Dental Student and Dental Practitioner it is important and necessary to learn the sterilization techniques followed in Endodontics which will  directly or indirectly lead to the success and good prognosis of your Endodontic treatment procedure.

Under given are the Basic and the Primitive methods of Sterilization followed in Endodontics regardless of any specific instruments

• Sterilize instruments by dipping in alcohol and flame 2-3 times where the composition is 3 parts of ethyl alcohol and 1 part formalin which will destroys even spores.
• Clean debris before any sterilization procedure regardless of method of sterilization.
• Wipe with 2*2 gauze moistened with hydrogen peroxide or alcohol which will clean the instruments.

Now lets discuss about the various types of Modern Sterilization techniques used :

1. Cold Steralization
2. Hot Salt Sterilizer
3. Glass Bead Sterilizer
4. Autoclave
5. Dry Heat Autoclave

Cold Sterilization:

Cold sterilization is a technique of sterilization which uses Chemical solutions to sterilize instruments.

The Various Solutions used are:

• Quaternary ammonia compounds-useful for vegetative microorganisms
• Ethyl alcohol and isopropyl alcohol-useful for vegetative bacteria and tubercle bacilli
• Alcohol –formalin solution- useful for vegetative bacteria, tubercle bacilli and spores.
• Orthophenylphenol and benzyl-para chlorophenol– Useful for Vegetative bacteria, tubercle bacilli, certain fungi and viruses, but not on spores.

SPORICIDIN :It is a solution of

• Phenol-7.05%
• Sodium tetraborate-2.35%
• Glutaraldehyde-2%
• Sodium phenate-1.2%

Which Disinfects instruments in 10 mins at room temperature and Sterilizes in 6.75 hours

Not recommended for 2 reasons:

1. Not effective against all varieties of microbial life
2. Time taken is long, Minimum 20 mins is required for complete and proper sterilization

Hot Salt Sterilizer:

It is used to sterilize:

• Absorbent points
• Broaches
• Files, reamers and other Root canal instruments should be sterilized just before usage

Technique and method of Sterilization using Hot salt sterilizer

• The instruments desired to be sterilized are put into the sterilizer and left for a period of time, where different instruments have diff time limits
• Hottest part of the salt bath is along the outer rim, starting at the bottom.
• Immerse instrument at least a quarter inch below salt’s surface and in the peripheral area.
• Consists of a metal cup in which table salt is kept at a temperature of 425*F[218*C] to 475*F[246*C].
• Thermometer to monitor temperature of the salt is necessary.
• Broaches,files and reamers are sterilized in 5 sec.
• Absorbent points and cotton pellets in 10 sec.
• It has superseded molten metal sterilizer and glass bead sterilizer because the metal or the glass beads occasionally cling to the wet instrument and tend to clog root canal.

Advantages Of Hot Salt Sterilizer:

• Use of table salt [readily available].
• Contains small amounts of sodium silicoaluminate,magnesium carbonate or sodium carbonate , so it pours readily and does not become fused under heat.
• Any salt carried in to RC can be irrigated easily.
• Salt should be changed weekly, or more often depending on the degree of humidity.
• Cost effective as salt is cheap and easily available

Glass Bead Sterilizer:

TEMPERATURE-218*C-246*C.

Glass beads should be less than 1mm in size because larger beads are not effective in transferring heat due to large air spaces between the beads.

• The instruments to be sterilized are immersed into the heated up glass beads and left for a period of time which is spefic for each instrument, which is mentioned below.
• RC instruments-5 secs
• Absorbent points[butt end first]and cotton pellets-10secs.
• Infected endodontic instruments exposed for 3 secs to a laser beam destroys microorganisms including spores.
• Dappen dishes can be sterilized before use by swabbing with tincture of thimerosal [merthiolate] under pressure.
• Long handled instruments, tips of cotton pliers, blades of scissors and other implements-dip in alcohol and flame twice.

This method is considered to be only an auxiliary method of sterilization.

Disadvantages:

• The Glass beads which are less than 1mm in diameter sometimes get stuck in the instruments like broaches or cotton pellets, and are introduced into the root canal.
• These small glass beads can prevent proper Root canal preparation.
• Costlier than the salt sterilizer

AUTOCLAVE

15lb pressure at 120*C[248*F] for 15 mins.

Carbon steel instruments tend to rust with autoclaving.

DRY HEAT AUTOCLAVE

Time consuming because it requires 2 hrs at a temperature of 320*F,1 hr at 340*F,or 30 min at 380*F.

Individual instruments can be sterilized in the following ways:

• Glass slab can be sterilized by swabbing with tincture of thimerosal,followed by a double swabbing with alcohol.
• Gutta-percha cones may be kept in sterile screw capped vials containing alcohol.
• To sterilize gutta-percha cone freshly removed from the box- immerse in 5.2% sodium hypochlorite for 1 min, then rinse with hydrogen peroxide and dry between 2 layers of sterile gauze.
• Silver cones are sterilized by passing them through a flame 3-4 times or by immersion in hot salt sterilizer for 5 secs.
• Use of instrument case in which root canal instruments are kept sterile by vapors of formaldehyde – not recommended. Because to be effective, formaldehyde gas must be in solution form or must enter in to solution with bacterial protoplasm.
• Bacteria on RC instruments are in a dry state,so bactericidal effect is reduced.