1. Infection Control And Sterilization In Dentistry
Dr. Huda Yasir

2. RATIONALE FOR INFECTION CONTROL
Microorganisms can spread from one person to another via direct contact, indirect contact, droplet infection and airborne infection.

3. Direct contact occurs by touching soft tissues or teeth of patients
Direct contact occurs by touching soft tissues or teeth of patients. It causes immediate spread of infection by the source.
Indirect contact results from injuries with contaminated sharp instruments, needle stick injuries or contact with contaminated equipment and surfaces.
Droplet infection occurs by large particle droplets spatter which is transmitted by close contact. Spatter generated during dental procedures may deliver microorganisms to the dentist.

4. CROSS-INFECTION
Cross-infection is transmission of infectious agents among patients and staff within a clinical environment.

5. Different Routes of Spread of Infection
Patient
DHCP
DHCP
Patient
DHCP= dental health care personel
Patient
Patient
Dental office to community
Community to patient

7. OBJECTIVE OF INFECTION CONTROL
The main objective of infection control is elimination or reduction in spread of infection from all types of microorganisms.
Basically two factors are important in infection control:
Prevention of spread of microorganisms from their
hosts.
Killing or removal of microorganisms from objects and
surfaces.

8. The Same Procedures Are Used For All Patients
STANDARD PRECAUTIONS
The Same Procedures Are Used For All Patients
Assume all patients are potentially infectious
Infection control policies are determined by the procedure, not the patient
sterile and non sterile gloves

9. UNIVERSAL PRECAUTIONS
These are as follows:
Immunization
Use of personal protective barrier techniques
Maintaining hand hygiene.
Some strategies have to be followed in order to reduce the risk of infection and transmission caused by blood borne pathogens such as HBV and HIV.

10. IMMUNIZATION:
all members of the dental team (who are exposed to blood or blood contaminated articles) should be vaccinated against hepatitis B.

11. Personal Protection Equipment : Barrier Technique
The use of barrier technique is very important, which includes gown, face mask, protective eyewear and gloves
Masks should be changed regularly and between
patients. • The outer surface of mask can get contaminated with
infectious droplets from spray or from touching the mask with contaminated fingers, so should not be reused.
• If the mask becomes wet,it should be changedbetween patients or even during patient treatment.
• The maximum time for wearing masks should not be more than one hour, since it becomes dampened from respiration, causing its degradation.
• In order to greater protection against splatter, a chin length plastic face shields must be worn, in addition to face masks.
• To remove mask, grasp it only by its strings, not by the mask itself

12. Gloves
Do not wash gloves before use or for reuse
Remove gloves that are cut, torn, or punctured

13. Hand Hygiene:
For most routine dental procedures washing hands with plain, non-antimicrobial soap is sufficient.
For more invasive procedures, such as cutting of gum or tissue, hand antisepsis with either an antiseptic solution or alcohol-based handrub is recommended.

15. Definitions
Cleaning: It is the process which physically removes contamination but does not necessarily destroy microorganisms. It is a prerequisite before decontamination by disinfection or sterilization of instruments since organic material prevents contact with microbes, inactivates disinfectants.
Disinfection: It is the process of using an agent that destroys germs or other harmful microbes or inactivates them. Disinfectant: It is a chemical substance, which causes disinfection. It is used on non-vital objects to kill surface vegetative pathogenic organisms, but not necessarily spore forms or viruses.

16. Antisepsis: It is the destruction of pathogenic micro-organisms existing in their vegetative state on living tissue. Antiseptic: It is a chemical applied to living tissues, such as skin or mucous membrane to reduce the number of microorganisms present
Sterilization: Sterilization involves any process, physical or chemical, that will destroy all forms of life, including bacterial, fungi, spores and viruses.

17. STERILIZATION AND DISINFECTION OF DENTAL INSTRUMENTS

18. CLASSIFICATION BASED ON
DENTAL INSTRUMENTS
CLASSIFICATION BASED ON
RISK OF TRANSMISSION AND NEED OF STERILIZATION
-CRITICAL
-SEMI-CRITICAL
-NON-CRITICAL

19. CRITICAL INSTRUMENTS
Penetrate MUCOUS MEMBRANES or CONTACT BONE, BLOODSTREAM, or other normally sterile tissues
HEAT STERILIZE between uses or use sterile single-use, DISPOSABLE devices
Examples include SURGICAL INSTRUMENTS,
SCALPEL BLADES, PERIODONTAL SCALERS, AND SURGICAL DENTAL BURS
There are three categories of patient-care items depending on their intended use and the potential risk of disease transmission.
Critical items penetrate soft tissue or contact bone, the bloodstream, or other normally sterile tissues of the mouth. They have the highest risk of transmitting infection and should be heat-sterilized between patient uses. Alternatively, use sterile, single-use disposable devices.
Examples include surgical instruments, periodontal scalers, scalpel blades, and surgical dental burs.

20. SEMI-CRITICAL INSTRUMENTS
Contact MUCOUS MEMBRANES but do NOT PENETRATE SOFT TISSUE
HEAT STERILIZE or HIGH-LEVEL DISINFECT
Examples: DENTAL MOUTH MIRRORS, AMALGAM CONDENSERS, AND DENTAL HANDPIECES
Semi-critical items contact only mucous membranes and do not penetrate soft tissues. As such, they have a lower risk of transmission.
Because most items in this category are heat-tolerant, they should be heat sterilized between patient uses. For heat-sensitive instruments, high-level disinfection is appropriate.
Examples of semi-critical instruments include dental mouth mirrors, amalgam condensers, and impression trays. Dental handpieces are a special case. Even though they do not penetrate soft tissue, it is difficult for chemical germicides to reach the internal parts of handpieces. For this reason, they should be heat sterilized using a steam autoclave or chemical vapor sterilizer.

21. NONCRITICAL INSTRUMENTS AND DEVICES
Contact intact SKIN
Clean and disinfect using a LOW TO INTERMEDIATE LEVEL DISINFECTANT
Examples: X-RAY HEADS, FACEBOWS, PULSE OXIMETER, BLOOD PRESSURE CUFF
Noncritical instruments and devices only contact intact (unbroken) skin, which serves as an effective barrier to microorganisms.
These items carry such a low risk of transmitting infections that they usually require only cleaning and low-level disinfection. If using a low-level disinfectant, according to OSHA, it must have a label claim for killing HIV and HBV. However, if an item is visibly bloody, it should be cleaned and disinfected using an intermediate-level disinfectant before use on another patient.
Examples of instruments in this category include X-ray head/cones, facebows, pulse oximeter, and blood pressure cuff.

22. The accepted methods of sterilization in our dental practice are:
Moist/steam heat sterilization
Dry heat sterilization
Chemical vapor pressure sterilization
4. Ethylene oxide sterilization.

23. Moist/steam heat sterilization
AUTOCLAVE
Sterilization with Steam Under Pressure
Time required at 1210 C is 15 mins at 15 psi of pressure.
Advantages
1. Time efficient. 2. Good penetration. 3. The results are consistently good and reliable. 4. The instruments can be wrapped prior
to sterilization.
Disadvantages
Blunting and corrosion of sharp instruments.
2. Damage to rubber goods.
Pounds per square inch – psi

24. Dry heat sterilization
Conventional dry heat ovens:
Achieved at temperature above 1600 C
for 2 hours
Advantages of dry heat sterilization
No corrosion is seen in carbon-steel instruments and burs
Maintains the sharpness of cutting instruments
Low cost of equipment
Disadvantages
Long cycle is required because of poor heat conduction and poor penetrating capacity
High temperature may damage heat sensitive items
such as rubber or plastic goods
Generally not suitable for handpieces
170°C 149°C 2.5 hr 180°C 160°C 2 hr
Time
1 hr 30 min

25. 3.Chemical vapor pressure sterilization
Chemiclaving
Operates at 1320 C and 20 lbs of
pressure for 30 minutes.
Active ingredient – 0.23% Formaldehyde
Advantages
Carbon steel and other carbon sensitive burs, instruments
and pliers are sterilized without rust or corrosion
Disadvantages
Items sensitive to elevated temperature will be damaged
Instruments must be very lightly packed.
Towel and heavy clothing cannot be sterilized.
lbs= pound

26. DISINFECTION OF DENTAL UNIT AND ENVIRONMENTAL SURFACES

27. DENTAL UNIT Cleaned by DISPOSIBLE TOWELING
EPA-ENVIRONMENTAL PROTECTIVE AGENCY
use an EPA registered hospital disinfectant
Cleaning Agents Like
PHENOLICS, IODOPHORS, CHLORINE containing compounds

28. ENVIRONMENTAL SURFACES
CLINICAL CONTACT SURFACES
High potential for DIRECT CONTAMINATION from spray or spatter or by contact with gloved hand.
HOUSEKEEPING SURFACES
Do not come into contact with patients or devices
LIMITED RISK of disease transmission
There are two categories of environmental surfaces.
Clinical contact surfaces have a high potential for direct contamination from patient materials either by direct spray or spatter generated during dental procedures or by contact with DHCP’s gloved hand. These surfaces can later contaminate other instruments, devices, hands, or gloves.
Housekeeping surfaces do not come into contact with patients or devices used in dental procedures. Therefore, they have a limited risk of disease transmission.

29. CLINICAL CONTACT SURFACES
This slide shows some examples of clinical contact surfaces, including a light handle, countertop, bracket tray, dental chair, and door handle (shown by arrows).
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.

30. CLEANING CLINICAL CONTACT SURFACES
Risk of transmitting infections greater than for housekeeping surfaces.
Surface barriers can be used and changed between patients. OR
Clean then disinfect using an EPA-registered low- (HIV/HBV claim) to intermediate-level (tuberculocidal claim) hospital disinfectant.
Because clinical contact surfaces come into direct contact with contaminated gloves, instruments, spray or spatter, their risk of transmitting infection is greater than for housekeeping surfaces. These surfaces can subsequently contaminate other instruments, devices, hands, or gloves.
Surface barriers can be used to protect clinical contact surfaces and changed between patients. Surface barriers are particularly useful for surfaces that are hard to clean, such as switches on dental chairs. This practice will also reduce exposure to harmful chemical disinfectants.
If surface barriers cannot be used, clean and then disinfect the surface with an EPA-registered hospital disinfectant effective against HIV and HBV (low-level disinfectant). If the surface is visibly contaminated with blood or other patient material, clean and then disinfect the surface with an EPA-registered hospital disinfectant with a tuberculocidal claim (intermediate-level disinfectant).

31. HOUSEKEEPING SURFACES
Examples of housekeeping surfaces are walls, sinks, and floors (shown by arrows).
Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great Lakes, IL.

32. Cleaning Housekeeping Surfaces
Routinely clean with SOAP AND WATER or an EPA-REGISTERED DETERGENT/HOSPITAL DISINFECTANT routinely
Clean MOPS AND CLOTHS and allow to dry thoroughly before re-using.
Prepare FRESH CLEANING AND DISINFECTING SOLUTIONS daily and per manufacturer recommendations.
Housekeeping surfaces carry the least risk for transmitting infections in dental settings. On a routine basis, these surfaces should be either cleaned with soap and water or an EPA-registered detergent/hospital disinfectant.
Wet mops and cloths may become contaminated with microorganisms, so clean the mop and cloths after use and allow them to dry thoroughly before re-using.
Prepare fresh cleaning and disinfecting solutions daily and per manufacturer recommendations.

33. THE END