Sterilization is one of the most important basic aspects in the whole of medical practice. Adequate attention has not been given to the prevention of cross contamination in the dental offices. This has occurred because we think that orthodontic procedures are usually non tissue invasive and also since the disease most identified with dentistry like hepatitis-B, was thought to be transmitted only by contact with blood of an infected carrier.
Individuals who are at the greatest occupational risk from cross infection in dental practice are the health professionals themselves. Recent studies indicate that orthodontists have the second highest incidence among dental professionals of acquiring hepatitis-B. Most orthodontic practices today are seeing patients from a much broader age group and socio-economic status. These people have a high risk of infectivity especially hepatitis-B.
Individuals undergoing treatment in dental office, like undetected hepatitis- B carriers and patients secreting herpes simplex viruses in saliva are asymptomatic and have the potential for transmitting the diseases. Diseases such as hepatitis-B and tuberculosis have long incubation period and so it is difficult to trace the source.
It would be very easy for an orthodontist to become involved in litigation, if a group of people were to develop a particular disease such as hepatitis with their only common source, the orthodontic office. The main concern facing the dentist is cross-infection, specifically, by the hepatitis virus. Hepatitis-B causes more death and practice disruption in dentistry than any other pathogen.
Hepatitis-B used to be called serum hepatitis and was thought to be transmitted only by parental routes. However, recent studies indicate that hepatitis-B can also spread through saliva and any instrument which comes into contact with blood or saliva of an infected or a carrier person. This virus can be transmitted from patient to dentist or patient to patient.
The greatest danger for orthodontist and his staff is from puncturing of the skin with contaminated instruments, sharp edges of orthodontic appliance, as any cuts or abrasions will allow micro-organisms to enter into the body. The microorganisms can also spread by direct contact with a lesion, by indirect contact through contaminated instruments or office equipments, by inhalation of aerosols induced by hand pieces and ultrasonic cleaners, and while scrubbing of instruments.
DEFINITION OF TERMS
Infection
This is an invasion and multiplication of micro-organisms in body tissues which may be clinically unapparent or results in local cellular injury due to competitive metabolism, toxins, intracellular replication or antigen antibody reactions response.
Cross Infection
This is the passage of micro-organisms from one person to another. The potential for cross infection in the dental office exists for direct or indirect transmission, as well as via aerosols routinely created during clinical procedures.
Disinfection
This refers only to the inhibition or destruction of pathogens. This is an adequate treatment for cleaning working surfaces of a dental unit. Disinfectant is a chemical agent that kills pathogenic and non-pathogenic micro-organisms but not spores. Recent studies say that there is no difference between pathogenic and nonpathogenic organisms. All micro-organisms can be pathogenic under certain circumstances.
Sterilization
It is the destruction or removal of all forms of life, with particular reference o micro-organisms; in other words destruction of bacteria, viruses, spores and fungi. The criterion of sterility is the absence of microbial growth in suitable media. The instrument used for sterilization is called sterilizer and the agents capable of this are called as sterilizing agents.
WHAT IS INFECTION CONTROL?
This is the governing or the limiting of the spread of infections via different channels, in a specific or general environment.
The procedures in the orthodontic office are of two major categories.
1. Those which interfere with the spread of infectious agents by reducing contamination.
2. Those which remove or kill the disease agents after contamination has occurred.
Need for Infection control
Orthodontic professionals are exposed to a wide variety of micro-organisms in the blood and saliva of the patients. These micro-organisms may cause infections such as Common cold (influenza), Pneumonia, T. B., Herpes, Hepatitis, A I D S etc. The use of effective infection control procedures in the orthodontic office prevent cross contamination that may extend to the dentist, other staff and patients.
Primary Goals of Infection control
To lower the risk of cross contamination by reducing the levels of pathogens.
To correct any break in aseptic technique.
To use universal precautions with every patient (treat every patient and instrument as potentially infectious).
To protect patients and personnel from occupational infections.
INFECTION CONTROL IN ORTHODONTICS
Diseases transmitted in an orthodontic office
a) Hepatitis-A: - Commonly known as infectious or contact hepatitis. It is often transmitted through the food chain. If it is treated properly, one would not become carrier.
b) Hepatitis-B: - This virus can survive for a week on hand pieces, equipments or uniforms.
c) Hepatitis non-A non-B: - The most common form of hepatitis, it usually results from blood transfusions.
d) Delta hepatitis: - It kills 12 to 22% of those infected. It is transmitted primarily through intravenous drug use.
e) Tuberculosis
f) Herpes Simplex: - Herpes I virus is the most easily transmitted; Herpes II, the venereal herpes, can’t be transmitted through saliva.
g) A I D S: - This deadly virus can be transmitted only through blood.
h) C M V (Cytomegalo Virus): - (Day care disease) A herpes like virus, spreads through improper sanitation.
Areas of infection control
1. Orthodontist and staff.
Basically, good personnel hygiene is the keystone of protection. The most important aspect of this is careful hand washing. They should be washed at least for a minute in cold water with germicidal soap. Cold water is suggested because hot water may cause pores to open. Then the use of a hand disinfectant is administered. Of course, after all preparations, proper gloves should be used. As far as the Orthodontist is concerned a reasonably complete medical history of his patient is important in determining who are
more likely to carry pathogenic organisms.
2. Instruments
The Orthodontist must decide for himself, which instruments need to be sterilized. Instruments can be of three categories.
a) Critical: - Instruments that penetrate the mucosa must be sterilized. E.g. Bands, band removers, ligature directors, band forming pliers etc.
b) Semi Critical: - Instruments that touches the mucosa should be sterilized. E.g. Mirror, retractors etc.
c) Least Critical: - Instruments such as Ligature tier and distal-end cutter, tying pliers, arch forming pliers, torquing keys, boons gauge etc. should be disinfected.
3. Operator site.
We should have in mind that our chair, table, light handles, spittoon, three way syringes etc., all become contaminated. It should be wiped frequently with 70% isopropyl alcohol. It is advisable to have straight tubing for your hand piece, three-way syringe etc. and to have hand pieces fitted with nonretraction valve. Minimize the no. of tubing and wires which can accumulate dust.
Primary Infection Control Measures
Patient Screening
A regular informative medical history of the patient can help to identify factors that assist in the diagnosis of oral and systemic disorders. Many patients often fail to give the information. Every patient should be treated as potentially infectious. This important fundamental application of infection control is termed as UNIVERSAL PRECAUTIONS. The blood and body fluid precautions substantially reduce the clinical guess work of a patient’s infection status.
Personal Protection
Repeated exposure to saliva and blood during the dental treatment procedures may challenge the dentist’s immune defense with a wide range of microbial agents. In this context, immunological protection and barrier protection are required
Immunological Protection
For immunological protection the operator should go for available vaccines of proven efficacy to prevent the onset of clinical or sub-clinical infection. The occupational risk of contacting hepatitis B, measles, rubella, influenza and certain other microbial infections can be minimized by stimulating artificial active immunity. The Orthodontists, their family members & the staff should undergo vaccination.
a) Hepatitis: - It needs a booster.
b) Rubella Vaccination:- It is against measles & does not need a booster.
c) Tetanus Immunization: - It needs a booster dose every ten years.
Barrier Control
Barrier protection is against the range of potential pathogens encountered during patient treatment. The physical barriers like disposable gloves, face masks, protective eyewear during treatment procedure will minimize the infectious exposure.
1. Use of disposable gloves, masks, protective clothing, protective eye wear, surface coverings and disposable materials.
2. Gowns must be cleaned daily.
3. Avoid rings bracelets, watches etc.
4. Should scrub the hands and use disinfectant before use of glove.
5. Gloves should be changed after every patient.
6. Use protective coverings, cover for dental light, handle, tray, covers and tubing for hand pieces, aspirator and air water syringe.
7. Let the patient rinse with antimicrobial mouth wash before treatment.
8. Except for few backup instruments, all instruments and pliers should be kept on sterilized trays / sterilizer.
9. Avoid handling the chart, telephone, pen, pencil etc., in between patients.
10.Use sensor lights instead of switches wherever possible.
11.Use sensor controlled water filter / foot operated water tap.
12.Disposable items should be burned immediately.
13.Impression should be disinfected immediately in the lab.
14.Protective eye-wear should be used in the lab.
15.Should not allow the splash from the lathe or other waste materials to be on the floor or table.
16.Avoid reusing the mixed pumice powder. Gloves Cuts and abrasions often found in fingers will serve as roots of microbial entry into the system when ungloved hands are placed in patient’s oral cavity – WET FINGERED DENTISTRY. Hand washing is not a substitute for use of gloves. Improper fitting gloves and reuse of gloves are not recommended. Washing of gloves with antiseptics increases the size and number of pinholes.
Protective eye wear
Eyes are more susceptible to physical and microbial injury because of their limited vascularity and diminished immune capacities. Droplets containing microbial contaminants can lead to conjunctivitis. Operator should have a protective eye wear during working. If protection eye wear is available for patients, it is advisable because hand pieces, sharp instruments, arch wires etc. are routinely passed over the patients face. Removing a patient’s glasses during dental treatment for the sake of comfort can no longer be recommended.
Masks
Face masks can protect the operator from microbe-laden aerosolized droplets. The best mask can filter 95% of droplets of 3.0 to 3.2 microns in diameter. Mask should fit around the entire periphery of the face. It is better to change the mask between each patient.
Washing and care of hands
Everything that is used inside the patient’s mouth in a clinic should besterile. Short nails will avoid tears in gloves and decrease the chance of patient discomfort and reduce the number of bacteria that can get trapped below it. Jewelry also should be avoided. Hand washing procedure should begin with scrubbing of all surfaces of nails, fingers, hands and lower arms with an antimicrobial preparation or detergent, followed by 2-3 minutes rinse with cold water and then application of a disinfectant. Hands should be dried with hot air or disposable paper towels, and should be followed by the use of disposable gloves. Use of gloves is not a substitute for routine hand washing.
Avoidance
Reduce the number of items that become contaminated. Reduce reusable items as much as possible. Most of the dental instruments are now available in disposable form.
Proper clinical attire
Appropriate dental clinic attire is a misunderstood area. Many practitioners place too much emphasis on choice of attire and not enough emphasis on correct protocol.
Current recommendations state that clinical attire should be changed at least once a day or when it becomes visibly soiled. Studies have shown that clinical attire easily becomes contaminated whenever a rotary instrument is used in the mouth. For this reason, a disposable cover must be worn over the gown when using rotary instruments. Either a cotton weave or preferably a polyester-cotton blend is acceptable.
Although OSHA (Occupational Safety and Health Administration) statement indicates that all exposed skin surfaces should be covered, short sleeved uniform may be acceptable. Intact skin is an adequate barrier against blood borne pathogens. Gowns should be with less buckles and buttons.
OSHA emphasizes that Street clothes and shoes must not be worn during patient treatment. Personnel must not wear clinic attire to and from the work place. Aprons / lab coats are to be used wisely. It is mandatory to use the aprons while examining patients or while working in the laboratory. These procedures will inevitably sow microorganisms into the fabric of the apron. Wearing the same garment to public places can result in distribution of the microorganisms to the areas visited and vice-versa. Wearing an apron does not necessarily badge you as doctor. Misusing clinical attire is as bad as not
following it.
Isolation
In a polyclinic or a multichaired clinic it is better to have isolation between the chairs. Ultrasonic cleaner, three way syringe etc. will cause transmission of organisms through aerosols.
Other barriers
Use of mouth wash
The use of an appropriate mouth wash prior to treatment procedure will reduce the total number of microbes in the oral cavity. Such a mouth rinse can reduce the number of oral microbes over a period while dental procedures are being performed.
Sharps disposal system
A sharps container is a mandatory part of the overall waste disposal system with in the dental office. Sharps container must be rigid, puncture proof, leak resistant and should be sterilizable.
Disinfection
Please note that disinfection procedures are advised only for those operatory surfaces and materials that cannot be routinely sterilized, such as, the table, dental chair and working surfaces, and for certain orthodontic instruments.
Surface disinfection
The operatory surfaces may become contaminated with saliva, blood or exudates. Disinfection of environmental surface is a two step procedure. An initial mechanical removal of tenacious organic debris is required. This is followed by application of an appropriate disinfectant. Separate surface cleaners and surface disinfectants may be employed. Surface disinfection can be done by scrubbing the surface with the iodophor-soaked gauze pads and allowed to dry. Then 70% isopropyl alcohol should be used to remove the residue. Vita wipes can be used instead of iodophors to avoid staining.
Use of Quaternary Ammonium Compounds and chemical agents are not advisable for orthodontic instrument. 8% solution of formaldehyde in alcohol and 2% aqueous solution of activated gluteraldehyde are acceptable.
Impressions / casts
The following four methods are acceptable for the disinfection of impressions:
Immersion in a chemical disinfectant such as 0.5 % - 1% sodium hypochlorite containing 1% chlorine, 2% gluteraldehyde for 60 minutes, 4% formaldehyde for 10 minutes. Even though gluteraldehyde is not effective against HIV and HBV, it is generally accepted.
Spraying of a disinfectant on the impression – 0.5% chlorhexidine in 70% alchohol
Usage of an ultraviolet disinfection unit.
Usage of an antiseptic containing alginate impression material.
Dental casts may be disinfected by adding discinfectant like iodophor or neutral gluteraldehyde to dry gypsum during the mixing process.
Instruments
Soaking in 2% gluteraldehyde for 100 minutes at room temperature is acceptable for disinfection of those orthodontic instruments which have been categorized as Least Critical instruments. These instruments should be scrubbed in soap water and then rinsed gently before use of the disinfectant.
Sterilization
Types of sterilization
Steam autoclave sterilization: - This process is very robust having excellent penetrating power. Unfortunately, it will corrode carbon steel items like burs, cutting instruments, orthodontic instruments etc. It will produce wet pouches at the end of the sterilization process. After steam sterilization the wet pouches should not be removed from the sterilizer until they are dry. Wet pouches will easily tear when handled. Some steam sterilizers have a post sterilization dry cycle and that should be used.
Dry heat sterilization: - It has a cycle time that is longer than most steam sterilizers but there is no corrosion of carbon steel instruments as long as the instruments are dry when loaded. Dry heat sterilizer yields completely dry packages.
Unsaturated chemical vapor sterilization : - This has a cycle time similar to the steam autoclave, and there is no corrosion of carbon steel instruments as long as the instruments are dry when loaded and are dry at the end of sterilization.
Liquid chemical sterilization: - This can be used only for items that cannot be heat sterilized. To achieve sterilization rather than incomplete microbial kill, these liquid chemical sterilants must be used for the proper contact time ranging from 3 – 12 hrs. depending on the sterilants being used. Instruments The instruments that are indicated for sterilization should be washed in soap water and then rinsed in running water to remove all debris, blood stains etc. Then it should be kept in ultrasonic cleaner. After ultrasonic cleaning, dry the instruments thoroughly (either by hand drying or by applying alcohol) and use water soluble oil to lubricate the hinged instruments to prevent corrosion. The sterilization method used can be selected according to our choice.
It is advisable to have a sterilizer, which has a steam sterilizing facility, a self drying and a storing facility. Dipping of instruments and bands in a solution of 1% sodium nitrate in deionised water and shaking them to remove excess solution will help in resisting rust formation.
Orthodontic Bands Heat sterilization of orthodontic bands destroys the ink that indicates band size. By using a plastic box with holes and dipping in gluteraldehyde solution, bands can be sterilized Ready cassettes are also available in the market for sterilization of
instruments and bands.
Packaging of instruments
Packaging the instruments before placing them into the sterilizer keeps the instruments in functional sets and protects them from re-contamination when they are removed from the sterilizer and during storage. Unwrapped instruments and unwrapped instrument cassettes have a zero-sterile shelf life after removal from the sterilizer.
Monitoring sterilization
Monitoring the effectiveness of the sterilization process in a particular time interval is very important. Spores of Bacillus stearothermophilus are used to monitor steam and unsaturated chemical vapor sterilizers, and spores of Bacillus subtilis are used to monitor dry heat sterilizers. In spore testing the biological indicators (spore strips or vials) are kept inside a regular instrument package. Spore testing can measure the use and functioning efficiency of sterilizers.
The other way is chemical monitoring which uses a special ink that changes color or form when exposed to sterilizing temperatures. These are in the form of autoclave tape, strips or tabs or special marking on the outside of the pouches.
Storage of sterilized instruments
Unpackaged instruments removed from the sterilizer have a zero –sterile shelf life. Do not allow packages to become compressed. Store the packages in a low dust area. The sterile shelf life is dependent upon the integrity of the packaging material. This is determined by assuring that the package never becomes wet, by observing the packaging for tears upon removed from storage, and when delivered to chair side for use on the next patient.
Hardness and Corrosion of instruments during sterilization.
Hardness
The stainless steel used in the manufacture of orthodontic pliers is formed at 18000 – 20000 F and tempered at 8000 - 9000 F. So these pliers cannot be damaged at temperature less than 8000 F. Carbide inserts in pliers can be damaged only at temperatures above 15000 F.
Studies shows cutters gain an increase in hardness after 500 cycles of sterilization. Dry heat produced the least and autoclave the most. Surface discoloration was visible on every plier after 500 cycles. The worst discoloration was seen in the chemiclaved instruments.
Corrosion
It is an electrolytic process in which the contact of two dissimilar metals or dissimilar areas within a single metal sets up a potential difference resulting in an electron flow. The electron flow leaves behind reactive ions that readily combine with atmospheric oxygen to form oxides (rust).
There are five types of electrolytic corrosion:
A) Solution corrosion: strong solutions such as blood or saliva formed electrolyte and caused corrosion as either an acid or base.
B) Debris corrosion: debris such as cement or dried blood sets up a potential difference resulting in electron flow and rust at the edges.
C) Heat corrosion: heat accelerates the corrosion process by increasing the rate of molecular reaction; heat itself will not cause corrosion.
D) Stress corrosion: it involves lattice distortion at the point of stress in metals, producing an area of differential electrochemical attack that may lead to breakage and corrosion.
E) Pit corrosion: the invaginated surface caused by scratches, hinge ware, or previous corrosion will produce pit corrosion. Galvanic reaction between dissimilar metals can also cause pitting.
Conditions such as extreme temperatures, physical abrasion, galvanism, or reactive extraneous ions that disrupt the chromium oxide layer will render the steel vulnerable to corrosion. Instruments made of carbon or 400 series steel are more susceptible than those of 300 series steel.
Recent studies showed no significant difference in mean wear whether sterilized with steam autoclave or dry heat.
To reduce corrosion:
Clean and remove debris from the instruments and rinse with distilled water.
Avoid tap water which contains dissolved alkali and metallic ions.
Water must be deionized and of good quality.
Keep the pH of steam above 6.4; otherwise pitting will occur.
Chrome plated instruments and stainless steel instruments should be sterilized separately because the electrolyte action can carry carbon particles from the exposed metal of a chromium plated instrument and get deposited on stainless steel.
It is better to keep the instruments in wrapping. Detergents with chloride bases should be avoided because chloride residue unites with steam to form HCl.
Detergents with pH of more than 8.5 may disrupt chromium oxide layer.
CONCLUSION
Effective infection control must be a routine component of professional activity. The use of universal precautions in the management of all patients greatly minimizes occupational exposure to microbial pathogens.
Discrepancy between “the ideal” and “the real” in dental asepsis provide fertile ground for rash statements of two kinds “sterilize everything versus do nothing, the mouth is a dirty place”.
Both are expressions of compulsion, fear or frustration about a seemingly impossible dilemma. They may reflect the sentiment “go away; let me alone”.
It is incumbent upon each orthodontist to conduct his practice in a manner that will not cause harm to anyone. By following the procedures outlined here, the orthodontist can minimize and even prevent the possibility of cross infection. This may be the best protection against the transmission of hepatitis and other diseases and perhaps, the filing of a malpractice suit. Practical reality, of course dictates that to prevent possible spread of
infectious diseases, dental professionals must be provided with up-to-date information that can be utilized to develop an optimal programme of asepsis.
Individuals who are at the greatest occupational risk from cross infection in dental practice are the health professionals themselves. Recent studies indicate that orthodontists have the second highest incidence among dental professionals of acquiring hepatitis-B. Most orthodontic practices today are seeing patients from a much broader age group and socio-economic status. These people have a high risk of infectivity especially hepatitis-B.
Individuals undergoing treatment in dental office, like undetected hepatitis- B carriers and patients secreting herpes simplex viruses in saliva are asymptomatic and have the potential for transmitting the diseases. Diseases such as hepatitis-B and tuberculosis have long incubation period and so it is difficult to trace the source.
It would be very easy for an orthodontist to become involved in litigation, if a group of people were to develop a particular disease such as hepatitis with their only common source, the orthodontic office. The main concern facing the dentist is cross-infection, specifically, by the hepatitis virus. Hepatitis-B causes more death and practice disruption in dentistry than any other pathogen.
Hepatitis-B used to be called serum hepatitis and was thought to be transmitted only by parental routes. However, recent studies indicate that hepatitis-B can also spread through saliva and any instrument which comes into contact with blood or saliva of an infected or a carrier person. This virus can be transmitted from patient to dentist or patient to patient.
The greatest danger for orthodontist and his staff is from puncturing of the skin with contaminated instruments, sharp edges of orthodontic appliance, as any cuts or abrasions will allow micro-organisms to enter into the body. The microorganisms can also spread by direct contact with a lesion, by indirect contact through contaminated instruments or office equipments, by inhalation of aerosols induced by hand pieces and ultrasonic cleaners, and while scrubbing of instruments.
DEFINITION OF TERMS
Infection
This is an invasion and multiplication of micro-organisms in body tissues which may be clinically unapparent or results in local cellular injury due to competitive metabolism, toxins, intracellular replication or antigen antibody reactions response.
Cross Infection
This is the passage of micro-organisms from one person to another. The potential for cross infection in the dental office exists for direct or indirect transmission, as well as via aerosols routinely created during clinical procedures.
Disinfection
This refers only to the inhibition or destruction of pathogens. This is an adequate treatment for cleaning working surfaces of a dental unit. Disinfectant is a chemical agent that kills pathogenic and non-pathogenic micro-organisms but not spores. Recent studies say that there is no difference between pathogenic and nonpathogenic organisms. All micro-organisms can be pathogenic under certain circumstances.
Sterilization
It is the destruction or removal of all forms of life, with particular reference o micro-organisms; in other words destruction of bacteria, viruses, spores and fungi. The criterion of sterility is the absence of microbial growth in suitable media. The instrument used for sterilization is called sterilizer and the agents capable of this are called as sterilizing agents.
WHAT IS INFECTION CONTROL?
This is the governing or the limiting of the spread of infections via different channels, in a specific or general environment.
The procedures in the orthodontic office are of two major categories.
1. Those which interfere with the spread of infectious agents by reducing contamination.
2. Those which remove or kill the disease agents after contamination has occurred.
Need for Infection control
Orthodontic professionals are exposed to a wide variety of micro-organisms in the blood and saliva of the patients. These micro-organisms may cause infections such as Common cold (influenza), Pneumonia, T. B., Herpes, Hepatitis, A I D S etc. The use of effective infection control procedures in the orthodontic office prevent cross contamination that may extend to the dentist, other staff and patients.
Primary Goals of Infection control
To lower the risk of cross contamination by reducing the levels of pathogens.
To correct any break in aseptic technique.
To use universal precautions with every patient (treat every patient and instrument as potentially infectious).
To protect patients and personnel from occupational infections.
INFECTION CONTROL IN ORTHODONTICS
Diseases transmitted in an orthodontic office
a) Hepatitis-A: - Commonly known as infectious or contact hepatitis. It is often transmitted through the food chain. If it is treated properly, one would not become carrier.
b) Hepatitis-B: - This virus can survive for a week on hand pieces, equipments or uniforms.
c) Hepatitis non-A non-B: - The most common form of hepatitis, it usually results from blood transfusions.
d) Delta hepatitis: - It kills 12 to 22% of those infected. It is transmitted primarily through intravenous drug use.
e) Tuberculosis
f) Herpes Simplex: - Herpes I virus is the most easily transmitted; Herpes II, the venereal herpes, can’t be transmitted through saliva.
g) A I D S: - This deadly virus can be transmitted only through blood.
h) C M V (Cytomegalo Virus): - (Day care disease) A herpes like virus, spreads through improper sanitation.
Areas of infection control
1. Orthodontist and staff.
Basically, good personnel hygiene is the keystone of protection. The most important aspect of this is careful hand washing. They should be washed at least for a minute in cold water with germicidal soap. Cold water is suggested because hot water may cause pores to open. Then the use of a hand disinfectant is administered. Of course, after all preparations, proper gloves should be used. As far as the Orthodontist is concerned a reasonably complete medical history of his patient is important in determining who are
more likely to carry pathogenic organisms.
2. Instruments
The Orthodontist must decide for himself, which instruments need to be sterilized. Instruments can be of three categories.
a) Critical: - Instruments that penetrate the mucosa must be sterilized. E.g. Bands, band removers, ligature directors, band forming pliers etc.
b) Semi Critical: - Instruments that touches the mucosa should be sterilized. E.g. Mirror, retractors etc.
c) Least Critical: - Instruments such as Ligature tier and distal-end cutter, tying pliers, arch forming pliers, torquing keys, boons gauge etc. should be disinfected.
3. Operator site.
We should have in mind that our chair, table, light handles, spittoon, three way syringes etc., all become contaminated. It should be wiped frequently with 70% isopropyl alcohol. It is advisable to have straight tubing for your hand piece, three-way syringe etc. and to have hand pieces fitted with nonretraction valve. Minimize the no. of tubing and wires which can accumulate dust.
Primary Infection Control Measures
Patient Screening
A regular informative medical history of the patient can help to identify factors that assist in the diagnosis of oral and systemic disorders. Many patients often fail to give the information. Every patient should be treated as potentially infectious. This important fundamental application of infection control is termed as UNIVERSAL PRECAUTIONS. The blood and body fluid precautions substantially reduce the clinical guess work of a patient’s infection status.
Personal Protection
Repeated exposure to saliva and blood during the dental treatment procedures may challenge the dentist’s immune defense with a wide range of microbial agents. In this context, immunological protection and barrier protection are required
Immunological Protection
For immunological protection the operator should go for available vaccines of proven efficacy to prevent the onset of clinical or sub-clinical infection. The occupational risk of contacting hepatitis B, measles, rubella, influenza and certain other microbial infections can be minimized by stimulating artificial active immunity. The Orthodontists, their family members & the staff should undergo vaccination.
a) Hepatitis: - It needs a booster.
b) Rubella Vaccination:- It is against measles & does not need a booster.
c) Tetanus Immunization: - It needs a booster dose every ten years.
Barrier Control
Barrier protection is against the range of potential pathogens encountered during patient treatment. The physical barriers like disposable gloves, face masks, protective eyewear during treatment procedure will minimize the infectious exposure.
1. Use of disposable gloves, masks, protective clothing, protective eye wear, surface coverings and disposable materials.
2. Gowns must be cleaned daily.
3. Avoid rings bracelets, watches etc.
4. Should scrub the hands and use disinfectant before use of glove.
5. Gloves should be changed after every patient.
6. Use protective coverings, cover for dental light, handle, tray, covers and tubing for hand pieces, aspirator and air water syringe.
7. Let the patient rinse with antimicrobial mouth wash before treatment.
8. Except for few backup instruments, all instruments and pliers should be kept on sterilized trays / sterilizer.
9. Avoid handling the chart, telephone, pen, pencil etc., in between patients.
10.Use sensor lights instead of switches wherever possible.
11.Use sensor controlled water filter / foot operated water tap.
12.Disposable items should be burned immediately.
13.Impression should be disinfected immediately in the lab.
14.Protective eye-wear should be used in the lab.
15.Should not allow the splash from the lathe or other waste materials to be on the floor or table.
16.Avoid reusing the mixed pumice powder. Gloves Cuts and abrasions often found in fingers will serve as roots of microbial entry into the system when ungloved hands are placed in patient’s oral cavity – WET FINGERED DENTISTRY. Hand washing is not a substitute for use of gloves. Improper fitting gloves and reuse of gloves are not recommended. Washing of gloves with antiseptics increases the size and number of pinholes.
Protective eye wear
Eyes are more susceptible to physical and microbial injury because of their limited vascularity and diminished immune capacities. Droplets containing microbial contaminants can lead to conjunctivitis. Operator should have a protective eye wear during working. If protection eye wear is available for patients, it is advisable because hand pieces, sharp instruments, arch wires etc. are routinely passed over the patients face. Removing a patient’s glasses during dental treatment for the sake of comfort can no longer be recommended.
Masks
Face masks can protect the operator from microbe-laden aerosolized droplets. The best mask can filter 95% of droplets of 3.0 to 3.2 microns in diameter. Mask should fit around the entire periphery of the face. It is better to change the mask between each patient.
Washing and care of hands
Everything that is used inside the patient’s mouth in a clinic should besterile. Short nails will avoid tears in gloves and decrease the chance of patient discomfort and reduce the number of bacteria that can get trapped below it. Jewelry also should be avoided. Hand washing procedure should begin with scrubbing of all surfaces of nails, fingers, hands and lower arms with an antimicrobial preparation or detergent, followed by 2-3 minutes rinse with cold water and then application of a disinfectant. Hands should be dried with hot air or disposable paper towels, and should be followed by the use of disposable gloves. Use of gloves is not a substitute for routine hand washing.
Avoidance
Reduce the number of items that become contaminated. Reduce reusable items as much as possible. Most of the dental instruments are now available in disposable form.
Proper clinical attire
Appropriate dental clinic attire is a misunderstood area. Many practitioners place too much emphasis on choice of attire and not enough emphasis on correct protocol.
Current recommendations state that clinical attire should be changed at least once a day or when it becomes visibly soiled. Studies have shown that clinical attire easily becomes contaminated whenever a rotary instrument is used in the mouth. For this reason, a disposable cover must be worn over the gown when using rotary instruments. Either a cotton weave or preferably a polyester-cotton blend is acceptable.
Although OSHA (Occupational Safety and Health Administration) statement indicates that all exposed skin surfaces should be covered, short sleeved uniform may be acceptable. Intact skin is an adequate barrier against blood borne pathogens. Gowns should be with less buckles and buttons.
OSHA emphasizes that Street clothes and shoes must not be worn during patient treatment. Personnel must not wear clinic attire to and from the work place. Aprons / lab coats are to be used wisely. It is mandatory to use the aprons while examining patients or while working in the laboratory. These procedures will inevitably sow microorganisms into the fabric of the apron. Wearing the same garment to public places can result in distribution of the microorganisms to the areas visited and vice-versa. Wearing an apron does not necessarily badge you as doctor. Misusing clinical attire is as bad as not
following it.
Isolation
In a polyclinic or a multichaired clinic it is better to have isolation between the chairs. Ultrasonic cleaner, three way syringe etc. will cause transmission of organisms through aerosols.
Other barriers
Use of mouth wash
The use of an appropriate mouth wash prior to treatment procedure will reduce the total number of microbes in the oral cavity. Such a mouth rinse can reduce the number of oral microbes over a period while dental procedures are being performed.
Sharps disposal system
A sharps container is a mandatory part of the overall waste disposal system with in the dental office. Sharps container must be rigid, puncture proof, leak resistant and should be sterilizable.
Disinfection
Please note that disinfection procedures are advised only for those operatory surfaces and materials that cannot be routinely sterilized, such as, the table, dental chair and working surfaces, and for certain orthodontic instruments.
Surface disinfection
The operatory surfaces may become contaminated with saliva, blood or exudates. Disinfection of environmental surface is a two step procedure. An initial mechanical removal of tenacious organic debris is required. This is followed by application of an appropriate disinfectant. Separate surface cleaners and surface disinfectants may be employed. Surface disinfection can be done by scrubbing the surface with the iodophor-soaked gauze pads and allowed to dry. Then 70% isopropyl alcohol should be used to remove the residue. Vita wipes can be used instead of iodophors to avoid staining.
Use of Quaternary Ammonium Compounds and chemical agents are not advisable for orthodontic instrument. 8% solution of formaldehyde in alcohol and 2% aqueous solution of activated gluteraldehyde are acceptable.
Impressions / casts
The following four methods are acceptable for the disinfection of impressions:
Immersion in a chemical disinfectant such as 0.5 % - 1% sodium hypochlorite containing 1% chlorine, 2% gluteraldehyde for 60 minutes, 4% formaldehyde for 10 minutes. Even though gluteraldehyde is not effective against HIV and HBV, it is generally accepted.
Spraying of a disinfectant on the impression – 0.5% chlorhexidine in 70% alchohol
Usage of an ultraviolet disinfection unit.
Usage of an antiseptic containing alginate impression material.
Dental casts may be disinfected by adding discinfectant like iodophor or neutral gluteraldehyde to dry gypsum during the mixing process.
Instruments
Soaking in 2% gluteraldehyde for 100 minutes at room temperature is acceptable for disinfection of those orthodontic instruments which have been categorized as Least Critical instruments. These instruments should be scrubbed in soap water and then rinsed gently before use of the disinfectant.
Sterilization
Types of sterilization
Steam autoclave sterilization: - This process is very robust having excellent penetrating power. Unfortunately, it will corrode carbon steel items like burs, cutting instruments, orthodontic instruments etc. It will produce wet pouches at the end of the sterilization process. After steam sterilization the wet pouches should not be removed from the sterilizer until they are dry. Wet pouches will easily tear when handled. Some steam sterilizers have a post sterilization dry cycle and that should be used.
Dry heat sterilization: - It has a cycle time that is longer than most steam sterilizers but there is no corrosion of carbon steel instruments as long as the instruments are dry when loaded. Dry heat sterilizer yields completely dry packages.
Unsaturated chemical vapor sterilization : - This has a cycle time similar to the steam autoclave, and there is no corrosion of carbon steel instruments as long as the instruments are dry when loaded and are dry at the end of sterilization.
Liquid chemical sterilization: - This can be used only for items that cannot be heat sterilized. To achieve sterilization rather than incomplete microbial kill, these liquid chemical sterilants must be used for the proper contact time ranging from 3 – 12 hrs. depending on the sterilants being used. Instruments The instruments that are indicated for sterilization should be washed in soap water and then rinsed in running water to remove all debris, blood stains etc. Then it should be kept in ultrasonic cleaner. After ultrasonic cleaning, dry the instruments thoroughly (either by hand drying or by applying alcohol) and use water soluble oil to lubricate the hinged instruments to prevent corrosion. The sterilization method used can be selected according to our choice.
It is advisable to have a sterilizer, which has a steam sterilizing facility, a self drying and a storing facility. Dipping of instruments and bands in a solution of 1% sodium nitrate in deionised water and shaking them to remove excess solution will help in resisting rust formation.
Orthodontic Bands Heat sterilization of orthodontic bands destroys the ink that indicates band size. By using a plastic box with holes and dipping in gluteraldehyde solution, bands can be sterilized Ready cassettes are also available in the market for sterilization of
instruments and bands.
Packaging of instruments
Packaging the instruments before placing them into the sterilizer keeps the instruments in functional sets and protects them from re-contamination when they are removed from the sterilizer and during storage. Unwrapped instruments and unwrapped instrument cassettes have a zero-sterile shelf life after removal from the sterilizer.
Monitoring sterilization
Monitoring the effectiveness of the sterilization process in a particular time interval is very important. Spores of Bacillus stearothermophilus are used to monitor steam and unsaturated chemical vapor sterilizers, and spores of Bacillus subtilis are used to monitor dry heat sterilizers. In spore testing the biological indicators (spore strips or vials) are kept inside a regular instrument package. Spore testing can measure the use and functioning efficiency of sterilizers.
The other way is chemical monitoring which uses a special ink that changes color or form when exposed to sterilizing temperatures. These are in the form of autoclave tape, strips or tabs or special marking on the outside of the pouches.
Storage of sterilized instruments
Unpackaged instruments removed from the sterilizer have a zero –sterile shelf life. Do not allow packages to become compressed. Store the packages in a low dust area. The sterile shelf life is dependent upon the integrity of the packaging material. This is determined by assuring that the package never becomes wet, by observing the packaging for tears upon removed from storage, and when delivered to chair side for use on the next patient.
Hardness and Corrosion of instruments during sterilization.
Hardness
The stainless steel used in the manufacture of orthodontic pliers is formed at 18000 – 20000 F and tempered at 8000 - 9000 F. So these pliers cannot be damaged at temperature less than 8000 F. Carbide inserts in pliers can be damaged only at temperatures above 15000 F.
Studies shows cutters gain an increase in hardness after 500 cycles of sterilization. Dry heat produced the least and autoclave the most. Surface discoloration was visible on every plier after 500 cycles. The worst discoloration was seen in the chemiclaved instruments.
Corrosion
It is an electrolytic process in which the contact of two dissimilar metals or dissimilar areas within a single metal sets up a potential difference resulting in an electron flow. The electron flow leaves behind reactive ions that readily combine with atmospheric oxygen to form oxides (rust).
There are five types of electrolytic corrosion:
A) Solution corrosion: strong solutions such as blood or saliva formed electrolyte and caused corrosion as either an acid or base.
B) Debris corrosion: debris such as cement or dried blood sets up a potential difference resulting in electron flow and rust at the edges.
C) Heat corrosion: heat accelerates the corrosion process by increasing the rate of molecular reaction; heat itself will not cause corrosion.
D) Stress corrosion: it involves lattice distortion at the point of stress in metals, producing an area of differential electrochemical attack that may lead to breakage and corrosion.
E) Pit corrosion: the invaginated surface caused by scratches, hinge ware, or previous corrosion will produce pit corrosion. Galvanic reaction between dissimilar metals can also cause pitting.
Conditions such as extreme temperatures, physical abrasion, galvanism, or reactive extraneous ions that disrupt the chromium oxide layer will render the steel vulnerable to corrosion. Instruments made of carbon or 400 series steel are more susceptible than those of 300 series steel.
Recent studies showed no significant difference in mean wear whether sterilized with steam autoclave or dry heat.
To reduce corrosion:
Clean and remove debris from the instruments and rinse with distilled water.
Avoid tap water which contains dissolved alkali and metallic ions.
Water must be deionized and of good quality.
Keep the pH of steam above 6.4; otherwise pitting will occur.
Chrome plated instruments and stainless steel instruments should be sterilized separately because the electrolyte action can carry carbon particles from the exposed metal of a chromium plated instrument and get deposited on stainless steel.
It is better to keep the instruments in wrapping. Detergents with chloride bases should be avoided because chloride residue unites with steam to form HCl.
Detergents with pH of more than 8.5 may disrupt chromium oxide layer.
CONCLUSION
Effective infection control must be a routine component of professional activity. The use of universal precautions in the management of all patients greatly minimizes occupational exposure to microbial pathogens.
Discrepancy between “the ideal” and “the real” in dental asepsis provide fertile ground for rash statements of two kinds “sterilize everything versus do nothing, the mouth is a dirty place”.
Both are expressions of compulsion, fear or frustration about a seemingly impossible dilemma. They may reflect the sentiment “go away; let me alone”.
It is incumbent upon each orthodontist to conduct his practice in a manner that will not cause harm to anyone. By following the procedures outlined here, the orthodontist can minimize and even prevent the possibility of cross infection. This may be the best protection against the transmission of hepatitis and other diseases and perhaps, the filing of a malpractice suit. Practical reality, of course dictates that to prevent possible spread of
infectious diseases, dental professionals must be provided with up-to-date information that can be utilized to develop an optimal programme of asepsis.
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