Applied surgery part ІІ


Critical items are the objects that can cause a high risk of infection if contamination takes place with any microorganism. It is the entry or the penetration into sterile tissue, cavity or bloodstream. It includes different equipment used in the sterile body cavities such as: surgical instruments, cardiac and urinary catheter and also ultrasound probes. It is necessary to sterilize the equipment with steam in order to kill all the microorganism on the Surface.


Semi-critical is defined as items that are in contact with non-intact skin or mucous membrane but do not penetrate soft tissues as such, they have a low risk of transmission. In this category, most of the items are heat-tolerant, the items should be heat sterilized carefully between patient uses. Some semi-critical items used on the human body include respiratory therapy and anaesthesia equipment. Cleaning process must precede high- level disinfection.

In the dental industry, semi-critical items include dental mouth mirror, amalgam condensers and impression trays. Dental hand pieces are a special case. Even though they don’t penetrate soft tissue, it is difficult for germicides to reach the internal part of the hand piece. Because of this reason, hand pieces should be heat sterilized using a steam autoclave or chemical vapour sterilizer.


Non-critical items require low level of disinfection. It includes items that are in contact only with intact skin. Examples of non-critical items include blood pressure cuffs, stethoscope, hospital beds and furniture.

For more information:

teeth 1

How to keep a sterilized and clean dental clinic

Why is disinfection and sterilization of instruments and devices necessary?

Disinfection is very crucial and necessary in dentistry, why? I´ve mentioned before in my previous post that we are surrounded by many different bacteria and there are bacteria in our presence that are pathogenic which can cause various types of diseases. Sterilization is the main key in dentistry. It is a benefit for the patient and the dentist. It provides a hygienic and sterile atmosphere which provides a better health care service for the patient, which results as positive feedback for the physician.

Critical items that are used should be highly sterilized in order to avoid transmission of pathogenic bacteria. When instruments have been used, they must be sterilized. Before autoclaving the instruments, they should be washed with a brush underneath cold water in order to remove the debris on the instruments. Then being placed in a box filled with an antiseptic solution, leave it in there for a couple of minutes. After a couple of minutes, it is time to pack, load and store the instruments.

Packing: Once the instruments are dry and clean, they should be wrapped and placed in a sterilizing packet in order to place it in an autoclave.

Loading: This step includes the placement and the position of the sterilants materials. It is important to allow free circulation of steam in order for the instruments to be fully sterile. Remember to place small pieces of the instruments in a small basket and place the tray parallel to the shelf in the autoclave.

Storing: when the sterilizing packets are removed from the sterilizer, it is important to store them in a clean,sterile and safe place and they are ready to be utilised again.

It is not only the instruments and the devices that should be clean and sterilized, the dental chair should be clean as well. In order to keep a hygienic dental environment it is important to clean the dental chair and the surrounding with an antiseptic spray, this will generate a positive response from the patients and it will make them comfortable and safe in the hands of the dentist.


Here below are two videos about cleaning instruments and cleaning dental chair (source:

Approach to Disinfection and Sterilization.

In our society, we are surrounded by a variety of different bacteria which can not be seen with a naked eye. That is why asepsis techniques are very essentail in health care departments. Sterilization and disinfection is necessary on medical devices and equipment directed on patient’s care. It is a critical aspect in order to eliminate and reduce the amount of pathogenic microorganisms.

There are different levels of aseptic technique that can be used, but the 3 most common methods are:

STERILIZATION: Defined as killing or removing all forms of microbial life (including endospores) in materials. It can be accomplished by various methods including

-Heat (most common)

-Gas plasma


-Bactericidal compound such as: Ethylene oxide and peracetic acid

-Aqeous compound such as: Gluteraldehyde

DISINFECTION: Defined as reducing the number of pathogenic microorganism to the point when they no longer cause any diseases. Unlike sterilization, disinfection does NOT kill endospores.

CLEANING: This method is used in everyday life and but is the less effective method. It is defined as removing visible soil and is usually applied by using water and detergent or any kinds of enzymatic products. Cleaning method should be done before high-level of disinfection and sterilization because of contamination of surfaces and instruments.


ANTISEPTIC: Is applied on living tissue,using antisepsis which is the absence of significant contamination. The technique that is used is called aseptic technique, this prevents contamination of surgical instruments,medical personnel and the patient during surgery. Aseptic technique are also used to prevent bacterial contamination in food industry.

DISINFECTANTS: Agents that destroy disease-causing microorganisms and their spores. It is applied to inanimate (lifeless) obejcts.

What is the difference between antiseptic and disinfectant?                                        

The difference between antiseptic and disinfectants is that antiseptic is ONLY used on the skin and not for surface disinfection. Whereas disinfectant is used on surface and NOT on the skin, because it can lead to skin injury and damage other tissues.