انت هنا الان : شبكة جامعة بابل > موقع الكلية > نظام التعليم الالكتروني > مشاهدة المحاضرة
الكلية كلية طب الاسنان
القسم ترميم ومعالجة الاسنان
المرحلة 4
أستاذ المادة احمد غانم مهدي الهلال
4/17/2011 5:40:36 PM
Sterilization:
Is the process of killing all living microorganisms including bacteria, spores, fungus and viruses to get microorganisms free condition in order to prevent transition of infectious disease.
Disinfection:
Is the process of killing the pathogenic microorganisms leaving the other microorganism.
The oral cavity is always heavily populated with different types of pathogenic and nonpathogenic microorganisms more than ground, tables or any object in the dental clinic, thus sterilization is essential in cleaning and preparing the instruments after using it.
Methods of sterilization:
1. Physical methods.
2. Chemical methods,
3. Combination methods.
1. Physical methods:
A. Autoclaving method (steam pressure):
This performed in a steam autoclave; the time required is 15 minute at (121 ?C) at 15 Ibs of pressure, but for warped instruments 7 min. is enough.
Advantages:
1. Rapid and effective method.
2. Most spores and viruses are killed.
3. Suitable for all dental instruments, clothes and towels.
Disadvantages:
1. Items sensitive to the elevated temperature cannot be autoclaved.
2. Autoclaving tends to rust carbon steel instruments and burs. Steam appears to corrode the steel neck and shank portions of some diamond instruments and carbide burs. Therefore these instruments should be putted in 2 % sodium nitrate solution before sterilization.
B. Dry heat method:
It’s readily achieved at 160 ? C temperature for 45 minutes or 170 ? C for 30 minutes.
Advantages:
1. Carbon steel instruments and burs do not rust, or corrode or loss its cutting edges if its well dried before sterilization.
2. Efficient and cheap.
Disadvantages:
1. The high temperature may damage some heat sensitive items such as rubber or plastic instruments and breaking mirrors.
2. Time consuming.
3. Crowding of instruments will defeat the sterilization.
C. Boiling water:
The instruments should be well cleaned before sterilization, and should be completely immersed in water to boil at 100?C for 10-30 min.
Advantages:
Rapid and cheap.
Disadvantages:
1. Does not kill spores.
2. The instruments will rust, to prevent this; sodium bicarbonate should be added to the water.
D- Ultrasonic vibration:
This depends on ultrasonic waves to clean endodontic instruments and burs prior to sterilization.
Advantages:
1. Six times more effective than hand cleaning.
2. Prevent trauma to operator hands.
3. Decrease the erosion of instruments.
Disadvantages:
It’s cleaning not sterilization method, and cannot kill spores.
E. Radical sterilization:
The sterilization depends on the use of radiation such as ultraviolet or x-ray or gamma ray.
Advantages:
Efficient in sterilization of disposable needles, local anesthesia and drugs.
Disadvantages:
1. Expensive.
2. The ray spend does not return.
2. Chemical methods:
In this method a chemical agent is used.
Properties of ideal chemical agent:
1. Destroy the microorganisms.
2. Should penetrate deeply through bacterial cell.
3. Rapid in action.
4. Does not damage the material or living tissue.
5. Retain its potency.
6. Soluble in water.
7. Not corrosive.
8. Does not stain the instruments.
Factors affecting on efficiency of a chemical agent:
1. Concentration of the chemical agent (according to manufacturer instruction).
2. Exposure time (the longer the best).
3. Temperature: (the higher temp. the more killing of microorganism).
4. PH.
5. Type of bacteria.
3. Combination methods:
In this method a chemical agent and physical method are combined.
A. Chemical vapor pressure (chemiclaving):
Sterilization by chemical vapor under pressure is performed in a chemiclave at 131?C, 20 Ibs and for 30 minutes.
Advantages:
Carbon steel and other corrosion sensitive burs, instruments and pliers are sterilized without rust or corrosion.
Disadvantages:
1. Items sensitive to elevated temperature will be destroyed.
2. Instruments must be tightly packed in a bags provided by the manufacturer.
3. Towels and heavily warped clothes may not be penetrated to provide sterilization.
B. Ethylene oxide sterilization:
It is the best method for sterilization of complex instruments, delicate materials and handpieces, the temperature of sterilization is at room temperature.
Advantages:
Less expensive device operates overnight to produce sterilization at room temperature.
Disadvantages:
Porous and plastic materials absorb the gas and require 24 hours aeration or more before it is safe for them contact skin or tissues.
Minimal dental office infection control program:
1. Sterilization of instruments and handpieces.
2. Comprehensive medical and dental history to detect the infectious diseases.
3. The dentist and dental staff must take hepatitis B vaccine.
4. Using rubber dam, disposable masks and gloves and wearing protective eye glasses.
5. Using surface cleaning and covers.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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