Clean: Absence of all matter in which micro-org. may find a favourable condition for growth.

Contamination: Presence of an infectious agent. (m-organism capable of producing disease)

Terminology

Germicide: Causing death of micro-organism.

Bactericidal: Causing the death of bacteria.

Bacteriostatic: Inhibition of bacterial growth

Terminology

Disinfection: Destruction of pathogenic agents. ( < than sterilization )

Sterilization: Destruction of all forms of life.

Terminology

Objectives of infection control

Never introduce microbes Never introduce microbes into the root canal system during endo. ttt.

Decrease the N. of existing microbesDecrease the N. of existing microbes to that normal body resistance can prevent infection.

Prevent cross-infection Prevent cross-infection disease.

Cleaning Disinfection Sterilization

Is 1st step where debris can be mechanical removed

How ? 1- Instruments should be wiped in

alcohol immediately.

Cleaning

2- Scrubbing gross debris on instrument with detergent in warm water using a BRUSH.

Ordinary Soap..............? alkaline film

3- An Ultrasonic Cleaner can be used in addition to hand scrubbing.

A-Chemical solutions:

B-Boiling and steam:

DisinfectionDisinfection

A-Chemical solutions: For thermo labile materials Gutta-Percha

Soln. Glutraldehyde, Iodophors Soln, → HIV & HBV.o Conc. changed regularly, in closed container o Disinfectant cycle starts, the addition of contaminated

instruments would disrupt the procedure.o Corrosion of instruments & Pt. sensitivity

Surface disinf. by NaOCL, Alcohols, Ammonium cop.

B-Boiling and steam:

Not capable of destroying all bacteria and spores and inefficient against Hepatitis virus.

They can not be used for sterilization.

1-Autoclaving2- Dry heat3-Chemical vapour 4-Ethylene oxide gas5- Salt (Glass) bead Sterilizers6- Flaming

SterilizationSterilization

1- Autoclaving: special closed system 100% steam Pressure 1-2.15 bar. Temp. 121-134 °C Time: 3-30 min.

Autoclaving

The disadvantageThe disadvantage (pressurized steam) are - Erosion of glass surface; - corrosive effect on sharp metal instruments, - Not suitable for paper, oils, powders and cotton

2- Dry heat:

At 160 °C for 60-90 min. suitable for sharp instruments, paper points, oils, and powders.

it is less effective for handpieces and rubber.

3- Chemical vapour

*Formaldehyde and alcohol with heat and pressure. *Temp: 137 °C under 1-1.5 bar pressure

*It is effective in killing all organisms * The corrosion is eliminated

*. Slightly longer times than the autoclaves.

4- Ethylene oxide gas: For heat labile materials .Powders, plastics,

delicate sharp instruments, motors & hand-pieces

Conc.: 450 mg/litre. Temp: 60 °C is used Time: several hours

Porous materials absorb some of the gas.

5- Salt (Glass) bead Sterilizers:This method is rapid & on bracket T. & just before RCT., not affect the sharp cutting edge

At 218 °C for 5-10 sec

Used to sterilize: Instrument’s tips. files Silver cones & Paper points cotton pellets (will chare off if kept in the sterilizer too long).

6- Flaming:

Effective only at actually touches. Ruin the cutting edge of the instruments.

Nowadays, not commonly used.