Hemostatic Suture Technique

As a continuation of the previous articles on suture techniques I am introducing another type of frequently used suture technique – hemostatic techniques. The technique is deemed to stop haemorrhage and reduce threats for patients.


  1. Pass the suture under the skin and across the vessel
  2. Turn 90 degrees and pass the suture perpendicular to the first suture (under the first suture)
  3. Tie a simple instrument knot to close the vessel
  4. Double knots are tied to secure that the vessel will not haemorrhage again



Instrumental Knotting

In a previous post I discussed about the different knots available for instrument ties; today I will like to demonstrate the basic instrument knot and the steps involved in it.


  1. You have your opened wound
  2. Take the plier and lift one side of the woundScreen Shot 2016-05-07 at 12.06.13.png
  3. Take your suture pin holder and pass the suture under the woundScreen Shot 2016-05-07 at 12.07.06.pngScreen Shot 2016-05-07 at 12.07.58.png
  4. Take the plier and lift the other side of the woundScreen Shot 2016-05-07 at 12.08.42.png
  5. Pass the suture from the other sideScreen Shot 2016-05-07 at 12.09.18.png
  6. Apply a double knot on the instrument and pull downScreen Shot 2016-05-07 at 12.09.47.png
  7. Cross the suture and tie it upScreen Shot 2016-05-07 at 12.10.52.png
  8. Apply a single instrument knot and pull tightScreen Shot 2016-05-07 at 12.11.49.pngScreen Shot 2016-05-07 at 12.11.49.png
  9. Cross the suture againScreen Shot 2016-05-07 at 12.13.22.png
  10. Apply another single instrument knot and pull tightScreen Shot 2016-05-07 at 12.14.02.png
  11. Remove excess string with scissorScreen Shot 2016-05-07 at 12.14.56.png

There you have it!

Remember don’t remove too much excess string as it can jeopardise your removal of the suture after patient recovery!

Video on Simple Instrument Knot

Dental Chair Cleaning

Today I want to demonstrate the steps into achieving a successful dental chair cleaning. As notice, this is just a demonstration example on how you can clean your dental chair after work everyday as there is no definite method in cleaning your dental chair. (Example)

Here you can check some basic foundations of dental chair cleaning

Remember gloves and protection are important!

First, take the surface disinfectant and spray across the surfaces of the dental chair.Screen Shot 2016-05-01 at 23.08.40.png

Then, take some paper towels and wipe the surfaces of the dental chair.

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Then take some antimicrobial wipes and wipe tray, handles, instrument panel as well as the light. (All surfaces that can contact soil during clinic hours!)

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Take the disinfectant of the suction tube and apply it.

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Lastly, remove the water filter of the dental chair and clean any soil remaining on the filter.

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Place the filter back in the dental chair and your cleaning process is completed.

Video Tutorial


Types of Sutures
Types of Sutures Available Now

Before talking about suture knotting, it is necessary to discuss the purpose of suture. Suture is to hold a wound together in good apposition until such time as the natural healing process is sufficiently well established to make the support from the suture material unnecessary and redundant.

Good knotting technique is known for its ability to close off a perfect suture; as there are many methods of knotting, scars will be different correlate to the knot. Here is a video on different suture knots currently used in medical practices.


(Suture Material used this time)

A common method is the simple instrument knot. Steps to a successful simple instrument knot:

  1. Carefully remove the suture blade in the front and dispose it into the hazardous item container
  2. Place the string over and under your material
  3. Tie a knot without pulling it completely
  4. Tie the second knot and pull it completely
  5. Test the strength of the knot

This knotting technique can let the suture be closed completely and is easy to remove after recovery. This is a tutorial on how to get a good simple knot by hand.

Surgical Scrub

I want to share my recent learning of the surgical scrubbing technique, as this is an important step before enter an operating room. Before entering an operating room, there are several steps to get you prepared and appropriately looked.

First, special clothes are worn in the operating room. The main purpose is to decrease the transmission of microorganisms between staff and patients. However, before putting on the surgical gown, scrubs are provided and used at the operating room’s changing room.


Steps to a successful scrubbing are–

  1. Turn on the water with your elbow, or if there is a paddle to turn on the water
  2. Rinse in order from fingers, palms, arms, and elbow
  3. Open the scrub pack and remove the scrub
  4. Rub your fingers, palms, arms, and elbow thoroughly (if the scrub is dropped into the sink, throw it into the trash and take a new one)
  5. Dispose the used scrub into the trash can
  6. Wash off all the bubbles from fingertips to the elbow (never from elbow to fingertips)
  7. And you should be good!


(This is the Betadine scrub the school provided.)


Sterilization in Our Own Practice

As mentioned in previous posts, sterilization is an important step in our dentistry practice. Both cross infection and contamination are harmful to our patients, staffs, and ourself. In order to achieve safe evidence-based practices, autoclave sterilization is my primary method regarding sterilizing instruments and supplies. Since gravity displacement autoclave is the currently available autoclave I can obtain, here is how I am going to apply it.
After my dental practice, my instruments are washed with tap water to remove any debris on them and put into 1% glutaraldehyde solutions for disinfection. Then the instruments with the glutaraldehyde solutions are put into the ultrasound cleaner for 15 minutes. The instruments are then transported to the packaging area. A single package consists of three components: a dental mirror, an explorer, and a plier. Other surgical equipments, for example an elevator for extraction of molars or a forcep, are packed as one instrument in one package. Trays are placed directly into the carrier of the autoclave, and cotton balls are put into a closed container for sterilization. Files for endodontic are placed in the specialized box for autoclave. Packages are put into the sterilization box and put into the autoclave.
Autoclave is set at 121°C (250°F) for 30 minutes and the filtered water are poured to the base of the autoclave. The sterilization process is then started. After 30 minutes, the sterilization box is removed from the autoclave and the packages are transported to the storage area. The most frequently used packages (dental mirror, explorer, and plier pack) are put at the first drawer. Other surgical equipments are put at the second drawer and are categorized by functions. Trays are also put at the first drawer.
Since the storage and sterilization need to be separated, the whole procedure will not have any chance of cross contamination. This is to ensure the patients received the best possible health-care we can provide.
(Cross contamination can be harmful)



Gravity Displacement Autoclave


Most medical and surgical devices used in healthcare facilities are made of materials that are heat-stable and therefore undergo heat (primarily steam) sterilization. However since 1950, an increase in medical devices and instruments made of materials that require low-temperature sterilization (i.e. plastics); therefore ethylene oxide gas had since been introduced for heat- and moisture- sensitive medical devices. Within the last two decades, new and improved low-temperature sterilization systems have been developed and utilized.

Sterilization is defined as the destruction of all microorganisms, as pathogenic or saprophytic bacteria, vegetative forms, and spores on the surface of an article or in a fluid to prevent disease transmission associated with the use of that item. Medical devices considered as critical items and should be sterile when used because any microbial contamination could result in disease transmission.

Of all sterilization methods, saturated steam under pressure (steam sterilization) is the most widely used and most dependable as it is nontoxic, inexpensive, rapidly microbicidal, sporicidal, and penetrates fabric. The basic principle of steam sterilization is to expose each item to direct steam contact at the required temperature and pressure for the specified time in an autoclave. There are four parameters of steam sterilization: steam, pressure, temperature, and time. The ideal steam for sterilization is dry saturated steam and entrained water (dryness fraction ≥97%). The ideal pressure is in relation with specific temperature, maintained for a minimal time, of 121°C (250°F) or 132°C (270°F). The required minimum exposure period for sterilization of wrapped healthcare supplies are 30 minutes at 121°C (250°F) in a gravity displacement sterilizer or 4 minutes at 132°C (270°F) in a pre-vacuum sterilizer.

There are two basic types of steam sterilizers (autoclaves): gravity displacement autoclave and high-speed pre-vacuum autoclave. In a gravity displacement autoclave, steam is admitted at the top or the sides of the sterilizing chamber and forces air out the bottom of the chamber through the drain vent. The penetration time into porous items is prolonged because of incomplete air elimination in the sterilizing chamber (i.e. the entrapped air remaining in a load of waste greatly retards steam permeation and heating efficiency). In a high-speed pre-vacuum autoclave however, steam penetration is instantaneous and regardless of porous loads. High speed pre-vacuum autoclave differs from gravity displacement autoclave that it ensures air removal from the sterilizing chamber and load before the steam is admitted.

(Video on Autoclave Process)

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The mode of microbicidal is moist heat destroys microorganisms by the irreversible coagulation and denaturation of enzymes and structural proteins. Steam sterilization should be used whenever possible on all critical and semicritical items that are heat and moisture resistant, even when not essential to prevent pathogen transmission; another use is decontamination of microbiological waste and sharp containers.

Another type of sterilization is flash steam sterilization. This method is applied in a gravity displacement autoclave at 132°C (270°F) for 3 minutes at 27-28 lbs of pressure with unwrapped object. Flash steam sterilization is a modification of conventional steam sterilization as equipments are placed in an open tray or placed in a specially designed, covered, rigid container to allow for rapid penetration of steam. The use of flash sterilization is considered acceptable for processing cleaned patient-care items that cannot be packaged, sterilised and stored before use. It is also used when there is insufficient time to sterilise an item by the preferred package method. Despite the short sterilization period, it is by no means for reasons of convenience or time saving. Several restrictions on the application of this method are: 1) implantable devices 2) orthopaedic screws and 3) plates as they need to be tracked for sterility and evaluated.

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Low temperature sterilization technologies also has been applied in different situations. Ethylene oxide (ETO) has been widely used as a low temperature sterilant as it is used to sterilise temperature- and moisture- sensitive medical devices and supplies in healthcare institutions. There are two types of ETO sterilizers available: mixed gas (ETO with CFC stabilizing agent of a ratio of 12% ETO and 88% CFC) and 100% ETO. However, as part of the Clean Air Act CFC were classified as a Class I substance and were prohibited for use. Alternative technologies have become available include: 100% ETO, ETO with a different stabilizing gas (carbon dioxide or hydrochlorofluorocarbons), immersion in peracetic acid, hydrogen peroxide gas plasma, and ozone.

One new technology is hydrogen peroxide gas plasma. Gas plasmas are generated in an enclosed chamber under deep vacuum using radio frequency or microwave energy to excite the gas molecules and produce charged particles. The free radicals produced within the plasma field with interact with essential cell components and disrupt metabolism of microorganisms. This method inactivates a broad range of microorganisms, including resistant bacterial spores, on materials and devices that cannot tolerate high temperature, humidity, and corrosion-susceptible metal alloys.

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Packing, loading and storing of instruments are necessary after sterilization. There are several packaging methods to maintain sterility of surgical instruments: 1) rigid containers, 2) peel-open pouches, 3) roll stock, 4) reels, and 5) sterilization wraps. The packaging material must allow penetration of the sterilant, provide protection against contact contamination during handling, provide an effective barrier to microbial penetration, and maintain sterility of the processed items after sterilization. An example of ideal sterilization wrap will successfully address barrier effectiveness, penetrability, aeration, ease of use, drape-ability, flexibility, puncture resistance, tear strength, toxicity, odour, waste disposal, linting, cost and transparency.

Loading items into the package must be arranged on all surfaces that will be directly exposed on sterilizing agents. A free circulation of steam (or sterilant) around each item. Several key principles in loading are: allow for proper sterilant circulation, perforated trays should be placed so the tray is parallel to the shelf, non-perforated containers should be placed on their edge, small items should be loosely placed in wire baskets, and peel packs should be placed on edge in perforated or mesh bottom racks or baskets.

Storage time can vary due to various environment and conditions. There are two types of practice currently applied in hospitals: time-related shelf-life practice and event-related shelf-life practice. The latter practice recognizes that the product should remain sterile until some event causes the item to become contaminated. Factors include bioburden, air movement, traffic, location, humidity, insects, vermin, flooding, storage area space, open/close shelves, temperature, and the properties of packages. In hospitals, sterile supplies should be stored far enough from the floor (8 to 10 inches), the ceiling (5 inches and 18 inches from sprinkler head), and the outside wall (2 inches) to allow adequate air circulation, ease of cleaning and compliance with local fire codes. Medical and surgical supplies should not be stored under sinks or in other locations where moist is present. Sterile items that become wet are considered contaminated because moisture brings with it microorganisms from the air and surfaces. Any package that has fallen or been dropped on the floor must be inspected for damage to the packaging and contents.

The sterilization procedure should be monitored routinely by applying a combination of mechanical, chemical and biological indicators to evaluate the sterilizing conditions and microbiologic status of the processed items. Physical monitoring includes checking the pressure gauge, temperature, and cycle time. Chemical monitoring are convenient and inexpensive but indicate that the item has been exposed to the sterilization process. Biological monitoring are recognised by most authorities as being closest to the ideal monitors of the sterilization process as they measure the sterilization process directly by using the most resistant microorganisms. New spore-strip biological indicators are self-contained in plastic vials and can produce a rapid-readout.

New rapid-readout ETO biological indicator has been designed for rapid and reliable monitoring of ETO sterilization processes. It detects the presence of B. atrophaeus by detecting a fluorescent signal.

If a false-positive biological indicator occur from improper testing or faulty indicators, it may be caused by improper storage processing, product contamination, material failure, or variation in resistance of spores. These results should be considered when applying sterilization processes.

Healthcare providers should be aware during all procedures of sterilization as any opportunistic infection can happen in all states. However, if standards and protocols are followed correctly, chances of infections can be greatly reduced and further guarantee a safer environment for patients and healthcare providers.

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(Video on General Overview of Sterilization and Disinfection Process)

Efficacy of Disinfection and Sterilization

Following last week’s article, I will like to talk about what are some factors that affect the efficacy of disinfection and sterilization in health-care facilities. As we all know that the concentration of germicide has far exceeded the bactericidal concentration; however, we also know that germicide can reduce susceptibility due to a number of factors. Some factors are intrinsic qualities of the organism, other factors are the chemical and external physical environment. If we are aware of these factors, we will be able to utilise the maximum effectiveness of the disinfection and sterilization process.

There are seven main factors in Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. First, the number and location of microorganisms. The larger the number of microbes, the more time a germicide needs to destroy all of them. Professor Spaulding demonstrated that it took 30 minutes to kill 10 Bacillus atrophaeus spores but took 3 hours to kill 100,000 Bacillus atrophaeus spores. The guideline recommends cleaning before disinfection or sterilization reduces the number of microorganisms and increases the safety margin of the germicide’s exposure time. The location of microorganisms must also be considered as medical instruments can be disassembled into many pieces. Medical instruments with multiple pieces must be disassembled; equipments such as endoscopes that have crevices, joints, and channels are prone to aggregation of microorganisms. As penetration of the disinfectant of these instruments can be limited due to limited surfaces, disinfection and sterilization process can be compromised.
Second, the innate resistance of microorganisms. As intrinsic resistance mechanisms in microorganisms to disinfectants vary, all disinfection strategies implicitly target the most resistant types of microorganisms to achieve complete destruction. The germicidal resistance demonstrated by gram-positive and gram-negative bacteria is similar with some exceptions. For example Pseudomonas aeruginosaRickettsiaChlamydia, mycoplasma, and Coxiella burnetti. These microorganisms behaved more resistant to disinfectants than other microorganisms.
Third, the concentration and potency of disinfectants. The more concentrated the disinfectant, the greater its efficacy and the shorter the time necessary to achieve microbial kill; however, must be noted that not all disinfectants are similarly affected by concentration adjustments. The disinfection time depends on the potency of the germicide as Professor Spaulding exemplified using Mucin-loop test that 70% isopropyl alcohol destroyed 10000 Mycobacterium tuberculosis in 5 minutes, whereas a simultaneous test with 3% phenolic required 2-3 hours to achieve the same level of microbial kill.
Fourth, physical and chemical factors. There are several factors in consideration that will influence disinfectant procedures: temperature, pH, relative humidity, and water hardness. Activity of most disinfectants increases as temperature increases, but some exceptions as excess increase in temperature causes disinfectants to degrade and weakens its germicidal activity. An increase in pH improves the antimicrobial activity of some disinfectants (i.e. glutaraldehyde, quaternary ammonium compounds) but decreases the antimicrobial activity of others (i.e. phenols, hypochlorites, iodine). Relative humidity is the single most important factor influencing the activity of gaseous disinfectants/sterilants (i.e. EtO, chlorine dioxide, formaldehyde). Water hardness reduces the kill rate of certain disinfectants because divalent cations in hard water interact with the disinfectant to form insoluble precipitates.
Fifth, organic and inorganic matters. Organic matters in the form of serum, blood, pus or fecal material can interfere with antimicrobial activity of disinfectants in two ways. Commonly, chemical reaction occurs between germicide and organic matter resulted into complexes that are less germicidal or non-germicidal thus reduced the active germicides available. Another interaction is organic material protects microorganisms from attack by acting as a physical barrier. Inorganic matters act as protective agents of microorganisms to all sterilization processes which result from occlusion in salt crystals. This further emphasised the importance of thorough cleaning of medical devices before any sterilization or disinfection procedures.
Sixth, duration of exposure. Medical devices and equipments must be exposed to germicide for the appropriate minimum contact time. Since all lumens and channels instruments must contact the disinfectant, air pockets must be eliminated during submersion. The disinfectant must be introduced reliably into the internal channels of the devices; overall, longer contact times are more effective than shorter contact times.
Seventh, biofilms. Biofilms are microbial communities that are tightly attached to surfaces and cannot be easily removed. Microorganisms may be protected from disinfectants by biofilms. Resistance include multiple mechanisms: physical characteristics of older biofilms, genotypic variation of the bacteria, microbial production of neutralising enzymes, and physiologic gradients within the biofilms. The presence of biofilms can significantly compromise the sterilization and disinfection procedures.
Disinfectants available to healthcare personnels and household uses are more similar than different. Disinfectants are not interchangeable and incorrect concentrations and inappropriate disinfectants can result in excessive costs. In this part I will give an overview of the performance characteristics of the two commonly used chemical disinfectants.
Chlorine and chlorine compounds, also known as “household bleach”, is one of the most widely used disinfectant. Hypochlorite is the most widely used of the chlorine disinfectants and is available in liquid (i.e. sodium hypochlorite). They have a broad spectrum of antimicrobial activity, do not leave toxic residues, unaffected by water hardness, are inexpensive and fast acting, remove dries or fixed organisms and biofilms from surfaces, and have low incidence of serious toxicity. Disadvantages of household bleach are ocular irritation, oropharyngeal burn, oesophageal burn, and gastric burn. Other disadvantages include metal corrosion in high concentration, inactivated by inorganic matter, discolouring of fabrics, release of toxic chlorine gas when mixed with ammonia or acid, and relative stability. The mode of action is free chlorine inactivates microorganisms. Microorganisms become inactive due to oxidation of sulfhydryl enzymes and amino acids, ring chlorination of amino acids, loss of intracellular contents, decreased uptake of nutrients, inhibition of protein synthesis, decreased oxygen uptake, oxidation of respiratory components, decreased adenosine triphosphate production, breaks in DNA, and depressed DNA synthesis.
Information of Sodium Hypochlorite
At low concentration, available chlorine have a biocidal effect on mycoplasma (25 ppm) and vegetative bacteria (<5 ppm). At high concentration (1000 ppm), chlorine can kill M. tuberculosis. 100 ppm will kill 99.9% of B. atrophaeus spores within 5 minutes and destroys mycotic agents in <1 hour. 5000 ppm of bleach can inactivate 1000000 Clostridium difficile spores in <10 minutes. Study has also shown that 200 ppm available chlorine can inactivate 25 different viruses in 10 minutes. 500 ppm of chlorine showed inhibition of Candida after 30 seconds of exposure. Data are available for chlorine dioxide that support manufacturers’ bactericidal, fungicidal, sporadical, tuberculocidal, and virucidal claims.
Hypochlorites are widely used in healthcare facilities in a variety of settings. Inorganic chlorine solution is used for disinfecting tonometer heads, spot disinfection of countertops, and floors. Household bleach and tuberculocidal disinfectant have been recommended for decontaminating blood spills. Small spills of blood can be treated with 1:100 dilution on 5.25%-6.15% sodium hypochlorite; however, large spills of blood must be treated with 1:10 diluted final concentration of sodium hypochlorite. CPR training manikins should be decontaminated by at least 500 ppm available chlorine for 10 minutes. Chlorine has long been used as disinfectant of water treatment; Legionella-contaminated hospital water system resulted in dramatic decrease (30% to 1.5%) in the isolation of L. pneumophilia from water outlets and a cessation of healthcare-associated Legionnaires’ disease in an affected unit. Hypochlorite solutions should be stored at room temperature (23 degrees Celsius) in closed opaque plastic containers but can lose up to 40-50% of free available chlorine over 1 month.
Some common bacterial resistance data
Glutaraldehyde is a saturated dialdehyde that has gained wide acceptance as a high-level disinfectant and chemical sterilant. Aqueous solutions of glutaraldehyde are acidic and generally not sporadical in this state. Only when the solution is activated (made alkaline) it becomes sporicidal. However, once activated the shelf life will be limited to 14 days. Later designed glutaraldehyde formulations have a life-span of 28-30 days while generally maintaining excellent microbial activities. The biocidal activity of glutaraldehyde results from its alkylation of sulfhydryl, hydroxyl, carboxyl, and amino groups of microorganisms, which alters RNA, DNA, and protein synthesis. The microbicidal activity can differs by different exposure time. With at least 2 minutes of exposure, glutaraldehyde can effectively kill vegetative bacteria. Within 10 minutes, M. tuberculosis, fungi, and viruses; within 3 hours, spores of Bacillus and Clostridium species. Glutaraldehyde is commonly diluted to 2% as high-level disinfectant and used for medical equipments, spirometry tubing, dialyses, transducers, anaesthesia and respiratory therapy equipment, hemodialysis proportioning and dialyse delivery systems, and reuse of laparoscopic disposable plastic tracers.
Glutaraldehyde Chemical Label
Glutaraldehyde safety handle should be very cautious. Healthcare personnels should be aware that usage of glutaraldehyde can exposed harmful vapour in a poorly ventilated room, so keeping a good ventilation is important. Acute or chronic exposure can result in skin irritation or dermatitis, mucous membrane irritation, or pulmonary symptoms.