CHAPTER 6: ARMAMENTARIUM & STERILIZATION

disinfection

may not inactivate all viruses or bacterial spores

used when sterilization is not possible to help prevent cross-contamination

reduces the number of viable microorganisms to an acceptable level but doesnt kill all of them

examples of disinfectants

alcohols

iodophors

chlorine dioxide

sodium hypochlorite

quaternary ammonium compounds

3 levels of disinfection

high level

intermediate level

low level

sterilization

destroys all microorganisms including viruses, bacteria, fungi, and spores

common cause of inadequate sterilization

• overpacking the sterilizer:

  • prevents proper steam penetration

heat-sensitive indicators

should not be interpreted as proof of sterility

best used to record that package was autoclaved

special tapes change color at sterilizer temperature

• limitations:

  • show only that temperature was reached

  • do not confirm sufficient time for proper killing

5 types of sterilization

dry heat

chemiclave

steam autoclave

ethylene oxide glass

immersion in liquid chemical (disinfection/sterilization)

common sterilization methods in dentistry

autoclaving

chemiclave

cold chemicals

dry heat sterilizer

cold chemicals

used only for heat-sensitive instruments

• limitations:

  • time cycle difficult to monitor

  • not time efficient for dentistry

  • require extended soak times

  • recommended only for items that cannot be heat sterilized

• safety concerns:

  • poisonous

  • harmful to patients even in small amounts

autoclaving

gold standard to sterilize endodontic instruments

uses water heated to produce steam under pressure to sterilize instruments, which is the most common method in healthcare

• statim autoclave → uses higher temps for faster cycles

• key parameters:

  o steam (water), time, pressure, temperature

• (if makwaan ug isa, di mugana so dapat naa tanan)

standard cycle of autoclaving

30 mins at 250°F (121°C) and 15 psi (amount of pressure)

flash sterilization of autoclaving

10 mins at 273°F (134°C) and 30 psi (amount of pressure)

advantages of autoclaving

excellent penetration of moist heat

instruments can be wrapped, extending shelf life

safe for most dental tools and cloth material

disadvantages of autoclaving

can dull or corrode sharp tools

requires air drying to prevent rust

not suitable for heat/moisture-sensitive items (like plastic/rubber, ortho mats)

chemiclave

uses a mix of 72% ethanol and 0.23% formaldehyde instead of water

• key parameters:

  o chemicals, time, pressure, temperature

cycle of chemiclave

270°F (132°C) at 20 psi for 20 minutes (including drying time)

advantages of chemiclave

fast turnaround time

ideal for carbon steel tools

prevents rust and dulling of instruments

disadvantages of chemiclave

requires proper ventilation

instruments may retain smell

releases strong chemical odors (formaldehyde)

not suitable for sterilizing liquids (use steam autoclave instead)

advantages of dry heat sterilizer

using still or forced air

prevent instrument corrosion

require no water or chemicals

disadvantages of dry heat sterilizer

long sterilization time

requires higher temperatures

wrapped items take longer and may need special wraps

cycle of still-air models

sterilize in 1 hour at 375°F (191°C)

forced-air models (like Cox) → do it in 6 minutes

glass bead sterilizer / salt sterilizer

used glass beads to transfer dry heat

uses chair-side sterilization between appointments

not recommended currently bc it is not effective

previously used for sterilizing endodontic instruments during treatment at 450°F (218°C) for a few seconds

—named salt bc it has pebbles of crystals (glass bead) that would heat up and will sterilize the instru

critical items

must be sterilized; single-use items discarded

touch sterile areas or enter the vascular system; penetrate oral mucosa

examples of critical items

files, nerve broaches

most of endo materials since they are introduced in the canals

semi-critical items

touch mucous membranes but do not penetrate tissues

sterilize if possible; otherwise, high-level disinfection

examples of semi-critical items

orthodontic tools

impression trays

nonsurgical burs and stones

examination and operative instruments

saliva ejectors, water syringe tips, lab prostheses

non-critical items

disinfection required

do not contact mucosa

touched by contaminated hands or fluids

examples of non-critical Items

x-ray tube head

instrument tables

dental chair headrest

dental light handles, spittoon

suction and saliva ejector handles

high-level disinfection

destroys all microorganisms except large numbers of bacterial endospores

advantages:

• HIV, fungi

• some spores

• M. tuberculosis

• effective against most microbes

disinfectants of high-level

glutaraldehyde

strong peroxides

o-phthaldehyde

intermediate-level disinfection

inactivates M. tuberculosis, most viruses, fungi, and vegetative bacteria (not spores)

advantages:

• suitable for surfaces and some medical tools

• effective against a wide range of pathogens

disinfectants of intermediate-level

chlorines

phenolics

iodophors

quats with alcohol 

low-level disinfection

kills most bacteria

some viruses and fungi

not effective against TB or spores

advantage:

• safe for general use on non critical surfaces

disinfectants of low-level

some phenolics

some iodophors

quaternary ammonium

common disinfectants for endo materials (gp, sealers, pp)

alcohol

glutaraldehyde

hydrogen peroxide

chlorhexidine (CHX)

polyvinylpyrrolidone iodine

sodium hypochlorite (NaOCI)

mixture tetracycline citric acid & detergent (MTAD)

chlorine dioxide

for instruments

operatory surface disinfection

advantages of chlorine dioxide

no rinsing, no residue

fast-acting (1-3 mins)

disadvantages of chlorine dioxide

corrosive to oxidized metals

must prepare fresh solution each time

sodium hypochlorite

surface disinfection

not for instruments

best friend!!!

advantages of sodium hypochlorite

effective

relatively quick (3-30 mins depending on debris)

disadvantages of sodium hypochlorite

highly corrosive to metals

iodophors

for HBV, TB, etc

broad-spectrum disinfection

advantages of iodophors

effective against many pathogens

slow iodine release enhances effect

disadvantages of iodophors

slower action (-30mins)

inactivated by hard water

alcohols

not accepted by ADA for surface or instrument disinfection

quaternary ammonium compounds

disapproved by ADA for dental use