Advantages And Disadvantages of Alcohol for Sterilization of Dental Surgical Instruments

一．Dental instruments

Oral surgical instruments is used for oral treatment, restoration of a class of instruments of the general term. Mainly divided into oral knife, chisel, oral scissors, oral forceps, oral forceps, clamps, oral hooks, needles and other instruments. Usually made of stainless steel material, can be reused.

二．ethanol CH3CH2OH

(1) Sterilizing:

95% alcohol is generally used to sterilize instruments. A high concentration of alcohol can be used to sterilize instruments such as UV wipes or camera lenses.

75% alcohol can generally be used for routine disinfection. For example, in clinical skin disinfection, mucous membrane disinfection or object disinfection, too high a concentration of alcohol will form a protective film on the surface of the bacteria, preventing it from entering the body of the bacteria, but it is difficult to kill the bacteria completely. If the concentration of alcohol is too low, although it can enter the bacteria, but it can not solidify the protein in the body, also can not kill the bacteria completely. Among them, 75% of the alcohol disinfection effect is the best.

② Environmental Hazards:

Volatile, flammable and irritating. Its vapor mixed with air into explosive gas. It can burn or explode when it meets high heat and open fire, and reacts violently with oxidizing agent chromic acid, calcium hypochlorite, hydrogen peroxide, nitric acid, silver nitrate, perchlorate, etc., and there is a danger of combustion and explosion. In the fire, the heated container has the danger of explosion. Its vapor is heavier than air, can diffuse to a considerable distance at a lower place, and will lead to backfire when exposed to fire.

(iii) Toxicity:

INHALATION: May irritate respiratory tract and mucous membranes. May cause effects harmful to the central nervous system, with symptoms including euphoria, intoxication, headache, dizziness, drowsiness, blurred vision, fatigue, tremors, seizures, loss of consciousness, lethargy, respiratory arrest and death.

Slightly irritating to the skin.

Exposure of the eyes to liquids, vapors, fumes or droplets may cause moderate irritation, and direct contact may cause irritation, pain, and the cornea may become inflamed or even damaged.

Ingestion: May cause effects harmful to the central nervous system, with symptoms such as "inhalation". Severe acute poisoning may cause hypoglycemia, hypothermia and extensor rigidity. Inhalation into the lungs may cause pneumonia. Chronic poisoning may cause liver, kidney, brain, gastrointestinal tract and myocardial deterioration.

Repeated or prolonged contact with the skin may result in sensitization, desquamation, redness, itching, inflammation, cracking and possible secondary infection.

May cause adverse reproductive effects.

Exposure of people who have had liver disease may increase the hazard.

Co-administration with other drugs may have adverse effects.

III. Disinfection and sterilization

According to the definition of disinfection, the killing and inhibition of microorganisms is divided into four levels, from high to low, namely sterilization, disinfection, antimicrobial and bacteriostatic.

Sterilization: A treatment that kills or removes all microorganisms (including bacterial spores) from the medium of transmission.

Disinfection: The process of killing or eliminating pathogenic microorganisms from a vector to render it harmless.

Antimicrobial: The process of killing bacteria or preventing them from growing and reproducing their activity by chemical or physical means.

Bacteriostasis: the process of inhibiting or hindering the growth and reproduction of bacteria and their activity by chemical or physical means.

Drugs used for disinfection are called disinfectants. According to the relevant national standards and health industry standards, preparations that can kill microorganisms on the transmission media and meet the disinfection requirements are classified into high-level disinfectants, medium-level disinfectants and low-level disinfectants according to the types of microorganisms they kill.

High-level disinfection: kills a wide range of microorganisms, including bacterial spores. Includes two levels, one for sterilization methods, which can deal with highly hazardous items, such as heat sterilization methods, ionizing radiation sterilization methods, ethylene oxide and chemical sterilizers such as formaldehyde and glutaraldehyde; and the second category is for high-efficiency disinfection methods, which can deal with moderately hazardous items, such as chlorine-containing disinfectants, peroxyacetic acid, hydrogen peroxide and so on.

Medium level disinfection: It can kill all kinds of microorganisms except bacterial spores, including all kinds of bacterial propagules, fungi, Mycobacterium tuberculosis, and all kinds of viruses. It can only be used for the disinfection treatment of general articles and the disinfection of skin and mucous membranes, such as iodine-containing disinfectants, alcohol disinfectants (mainly ethanol, isopropanol and n-propanol), phenol disinfectants and ultraviolet rays.

Low level disinfection: can kill bacterial propagules, lipophilic viruses, etc., cannot kill fungi and Mycobacterium tuberculosis, cannot inactivate hepatitis B virus, etc.. Can only be used for cleaning and sterilization, skin and mucous membrane hygiene disinfection, such as ultrasonic, chlorhexidine, quaternary ammonium salt, and so on.

IV. Advantages and disadvantages of alcohol sterilization

(1) Advantages:

①Bactericidal ability

Alcohol is effective in killing a wide range of bacteria and viruses, including common oral pathogens.

Alcohol at a concentration of 75% kills enveloped viruses and bacteria, such as hepatitis B virus, hepatitis C virus, and influenza virus.

Viruses and bacteria with envelopes are generally an enveloped DNA virus, and the presence of such a virus, by spraying with alcohol, can result in the loss of water within the viral envelope and the destruction of the envelope, which serves to inactivate the virus.

Alcohol sterilization is a common form of disinfection in medicine, and if 75% alcohol is used, it can kill most enveloped viruses. Enveloped viruses are viruses that have an envelope outside the protein. The envelope can be dissolved by lipid solvents, and alcohol is a lipid solvent, so it can have a chemical reaction with the viral envelope, thus dissolving the envelope tissue and thus killing the enveloped viruses, such as the influenza virus, the AIDS virus, and the varicella-zoster virus. If less than 75% alcohol is used for disinfection, the concentration of alcohol is too small, then the alcohol may not be able to destroy the virus cells; if a high concentration of alcohol is used but the disinfection time is short, it may not be able to completely destroy the virus, and the disinfection effect cannot be achieved.

Further, alcohol disinfection may be relatively ineffective against some alcohol-resistant microorganisms. Some bacteria and viruses have gradually developed resistance to alcohol, making them less sensitive to alcohol-based disinfectants.

② Alcohol has a faster sterilization rate

Alcohol kills most microorganisms quickly, thus shortening the time it takes to sterilize instruments.

(iii) Alcohol is less toxic and irritating

When used correctly, alcohol does not have significant side effects on the body.

④ Alcohol is characterized by rapid evaporation

Dries surfaces quickly and leaves no residue.

(2) Disadvantages:

① Alcohol is not suitable for killing all types of microorganisms. Specific viruses, fungi or spores are resistant to alcohol. Alcohol is generally not useful for naked viruses.

Naked viruses: are viruses that are not encapsulated by an epitaxial lipid bilayer membrane and have only a nucleus and capsid, and have a very simple structure consisting only of a genome and proteins. It is often parasitized in the host cells, and alcohol cannot achieve the killing effect because it is protected by other tissues of the body. Such viruses generally include hepatitis A virus, poliovirus, rabies virus, adenovirus, and rotavirus. Compared to enveloped viruses, these viruses are more resistant and insensitive to lipid solvents, such as soapy water and ether, and the capsid is highly immunogenic, stimulating the immune system to produce antibodies.

One of the characteristics of naked viruses is that they cannot independently enter the host cell to replicate and need to be transmitted through other vectors such as insect bites, human or animal body fluids. Once a naked virus has entered a host cell, it will use the host cell to replicate and release new virus particles.

② Alcohol is volatile.

Its sterilizing ability may be weakened by volatilization during use. It is necessary for doctors to take care of timely replenishment when using alcohol to sterilize instruments to ensure stable disinfection effect.

(iii) Alcohol has a dissolving effect on some plastics and rubber materials.

If the instrument is not made of a material suitable for contact with alcohol, it may be damaged or rendered ineffective.