1. Asepsis Or Sterilization ?

2. Welcome

3. Dr. Alan Al-Qassab B.D.S (Bachelor in Dental Surgery)
H.D.D (High Diploma in Orthodontic Dentistry)
M.Sc. (Master in Oral and Maxillofacial surgery)
MOMSRCPS (Doctorate in Oral and Maxillofacial surgery)
Membership in Oral and Maxillofacial surgery in the Royal College of Surgeons Glasgow

4. Definitions

5. Cleaning
It is a process which removes visible contamination, but does not necessarily destroy microorganisms. It is a necessary prerequisite for effective disinfection or sterilization.

6. Asepsis It is the avoidance of pathogenic organisms.
It is the term used to describe methods which prevent contamination of wounds and other sites, by ensuring that only sterile objects and fluids come into contact with them, and that the risk of air-borne contamination is minimized.

7. Antisepsis Antiseptic:
It is the procedure or application of an antiseptic solution, or an agent which inhibits the growth of micro-organisms, while remaining in contact with them,
but does not necessarily imply sterility. The examples are scrubbing up and preparation of operative sites.
Antiseptic:
It is a chemical, applied to living tissues, such as skin or mucous membrane to reduce the number of micro-organisms present, by inhibition of their activity
or by destruction.

8. Disinfection Disinfectant:
It is a process which reduces the number of viable pathogenic micro-organisms to an acceptable level, but may not inactivate some viruses and bacterial endospores.
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.

9. Sterilization
It is the process of destruction or removal of all microbial forms.

10. classification of Instruments and equipment in surgery

11. A. Critical
Instruments which penetrate mucous membrane or contact bone, the bloodstream or other normally sterile internal tissues, e.g. surgical instruments, scalpel, blades, surgical dental burs, needles, periodontal scalers, etc.

12. B. Semicritical Instruments which contact mucous
membrane, but do not penetrate the soft tissues,
e.g. mouth mirrors, dental handpieces, etc.
It is heat sterilize or high level disinfectant.

13. C. Noncritical Instruments which contact intact
skin. For example, X-ray heads, face bows, pulse oximeter, blood pressure cuff, etc.

15. 1. Transport of used items 2. Cleaning and disinfection
Clean and disinfect using a low to intermediate level disinfectant: Correct cleaning, packaging, sterilizer loading procedures, sterilization methods or high level disinfection methods should be followed to ensure patient safety.
1. Transport of used items
2. Cleaning and disinfection
3. Preparation and packing
4. Sterilization
5. Storage.

16. Cleansing of Instruments

17. cleansing agents
They are commonly used for the removal of debris from the instruments. Soaps: They are effective at pH 9 or higher and even in a weak acidic environment, or in one containing soluble salts of calcium and magnesium, precipitation of soap will occur. Detergents: They are compatible with calcium and magnesium ions and maintain their efficiency in neutral or slightly acidic solutions. Some detergents possess bactericidal activity against some specific gram positive organisms. For example, sodium lauryl sulfate is effective against Strep pneumoniae. Other fat solvent solutions: Such as acetone, ether, and xylene, are sometimes used in cleaning.

18. 1. “ Sterile” does not mean safe and clean. 2
1. “ Sterile” does not mean safe and clean. 2. An item heavily loaded with microbiological material will be more difficult to sterilize than one lightly contaminated. 3. Medical devices/instruments must be thoroughly cleaned to reduce organic material before sterilization and as soon as possible after use. This is the most effective stage of any decontamination procedure, which should accompany or precede all disinfection procedures.
4. Dried biological material is much more difficult to remove than fresh deposits. Blood with its content of iron, acid and sodium chloride is highly corrosive.
5. Improperly cleaned instruments if sterilized may be free of living micro-organisms, but they will be smeared with endotoxins—“the corpses of bacteria”, which can trigger very strong inflammatory reactions in the body.
6. Presoak the instruments after use in water or an enzyme solution. This prevents drying of saliva and blood.

19. 7. Manual scrubbing or washing in still/stagnant water increases the microbial count; hence should be avoided. 8. Automated washer disinfectors offer the safest, most reliable option, provided they are suitably monitored and maintained. 9. As an alternative to washer disinfectors (dishwasher), ultrasonic cleaning bath is recommended Use of single use disposable items and equipment whenever possible. 11. Consider items difficult to clean (endofiles, broaches and burs) as single use disposables and discard them after each use.

20. packaging or Wrapping

21. Packing instruments before sterilizing prevents them from becoming contaminated after sterilization till it is opened and used. Instruments must be clean, but not necessarily dry. Closed (non perforated) containers (closed metal trays, capped glass vials) and aluminum foils cannot be used, because they prevent the steam from reaching the inner sections of the packs.

22. marking of packs
Packs should have some external indication, showing that the pack has been processed. Autoclave tapes on packs change color after exposure to sterilization cycle. That does not prove sterilization, hence, it should be used in conjunction with the test for cycle sterilization. Each pack must be labeled with the contents, date of sterilization, autoclave number, and load number. This will help in locating processed items in case of recall.

23. Methods of sterilization

24. Sterilization can be defined as the use of a physical or chemical procedure to destroy all forms of micro-organisms including bacteria, spores, fungi, and viruses. The term sterilization can only be applied to instruments, and not to skin, where only antisepsis can be achieved. A general principle is that all items used to penetrate soft tissue or bone, enter into or contact the blood stream or other normally sterile tissues, should be sterilized and be sterile at the point of use. A sterility requirement for medical products means that the theoretical probability that a living organism will be present on an object after the sterilizing process is equal to or less than one in a million, so-called sterility assurance level (SAL) = 10 degree.

25. Sterility may be achieved by: Heat (2) Chemical
(3) Ionizing radiation.
Most commonly used methods are as follows:
(i) by steam; or moist heat, at a raised
atmospheric pressure, in an autoclave,
(ii) by dry heat/ hot air, at normal atmospheric pressure, in a dry oven,
(iii) by use of ethylene oxide,
(iv) by low-temperature steam and formaldehyde (LTSF) and
(v) by irradiation.

26. principles
1. All used instruments should be thoroughly cleaned; all deposits of blood and debris should be removed before sterilization. 2. It is essential for the sterilizing agent (heat, steam and/or gas) to be in contact with every surface of each item to be sterilized for the specified period of time at the specified temperature. 3. All sterilizing equipment must be regularly serviced and maintained by suitably qualified engineers. Appropriate test must be applied to check temperature, humidity, pressure, and gas content when appropriate; and which proves the elimination of bacteria and spores. 4. The manufacturer’s instructions should be strictly adhered to for its operation and maintenance. Heat is the most common and one of the most effective, simplest methods of sterilization. Heat may be transmitted through air, water, or oil. Heat method can be utilized in two forms: (i) moist heat, and (ii) dry heat.

27. moist/steam Heat sterilization: autoclave
Steam sterilization involves heating water to generate steam in a closed chamber (Autoclave—in which drums and trays with the materials to be sterilized can be kept inside) producing moist heat that rapidly kills microorganisms. There is a mass heat transfer as the steam condenses. Use of saturated steam under pressure is the most practical, quickest, safest, effective, economic method of sterilization, known for the destruction of all forms of microbial life, because of its: (i) high penetrating capacity, and (ii) it gives up a large amount of heat (latent heat) to the surface with which it comes into contact, and on which it condenses as water. The advantages are: (i) the results are consistently good

28. There are two types of autoclaves or steam sterilizers available:
1. Downward (gravitation) displacement sterilizer: This is nonvacuum type autoclave.
2. Steam sterilizers (autoclave) with pre- and postvacuum processes—Class B type

29. dry Heat sterilization
Dry heat sterilization involves heating air with transfer of heat energy from the air to the instruments. It is an alternative method of sterilization of instruments,

30. Hot Air Oven
It is used to sterilize items which do not get damaged by high temperatures, such as laboratory glassware, glass syringes and instruments. Hot air is a poor conductor of heat and has poor penetrating capacity. It does not penetrate grease, oil, and powders; and equipment containing these substances should be sterilized by other methods. High temperature damages fabrics and melts rubber/plastic, hence should not be sterilized by this method.

31. It is achieved by two methods:
1. Dry heat oven type sterilizer (static air): It has coils and heat rises within 60 to 120 minutes at 320ºF or
160ºC.
2. Dry heat: Rapid heat transfer (forced air) at high velocity within 12 minutes at 375ºF/190ºC. For
wrapped items and within 6 minutes at 375ºF for unwrapped items.

33. Ethylene oxide gas sterilization
Ethylene oxide gas is an alkaline, non-corrosive agent, highly penetrative that infiltrates packaged medical devices to kill bacteria, spores and viruses. Eto is toxic and flammable/explosive at low temperatures (flash point of –20ºC) so it is used on products that could get damaged or cannot withstand high temperature processes used to sterilize objects sensitive to temperatures greater than 60º such as plastics, optics and electrical. It destroys micro-organisms by alkylation;

34. Irradiation
Radiation used for sterilization is of two types: (i) ionizing radiation, e.g. X-rays, gamma rays, and high-speed electrons and (ii) nonionizing radiation, e.g. ultraviolet light, and infrared light. These forms of radiation can be used to kill or inactivate microorganisms.

35. disinfection
Disinfection (high level disinfection) is the term used for destruction of all pathogenic organisms, such as, vegetative forms of bacteria, mycobacteria, fungi and viruses, but not bacterial endospores, from inanimate surfaces, such as walls, furnishings, and equipment; and antisepsis is the term applicable to living tissues such as skin and mucous membrane.

37. disinfectants
A disinfectant may be classified, on the basis of their properties, into the following: bactericidal, sporicidal, viricidal and fungicidal. They are usually used for decontamination of inanimate objects. The increase in their efficiency is related to increased toxicity. Certain

38. antiseptics
An antiseptic is a chemical disinfectant (usually bacteriostatic in the concentration it is used) that can be diluted sufficiently to be safe for application to living tissues (intact skin, mucous membranes, and wounds) while still retaining its antimicrobial property. They are less toxic than the disinfectants or the agents used for sterilization. Notable antiseptic agents include: alcohols, aqueous quarternary ammonium compounds, hexachlorophene, and iodophor compounds.