DENT 1111 Section 3 Notes PDF

Chapter 18 - Microbiology Understanding Microbiology understanding the nature of pathogens and ways to prevent the transmission of diseases microbiology - study of microorganisms nonpathogenic - do not produce human illnesses Major Groups of Microorganisms Bacteria makeup large group of one celled m...

Chapter 18 - Microbiology Understanding Microbiology understanding the nature of pathogens and ways to prevent the transmission of diseases microbiology - study of microorganisms nonpathogenic - do not produce human illnesses Major Groups of Microorganisms Bacteria makeup large group of one celled microorganisms that vary in shape, size and arrangement. most bacteria are capable of living independently under favourable conditions. human body is the host of many harmless bacteria on skin, in respiratory tract, and gastrointestinal tract; called normal flora shape - most bacteria can be classified according to shape when under a microscope. ◦ cocci (spherical) - dividing in two, forming chains called streptococci ◦ bacilli (rod) ◦ spirochetes (spiral) - bacteria has flexible cell walls capable of movement gram-positive and gram-negative bacteria - danish bacteriologist Hans Christian Gram, developed 4 step staining process to different cell walls. ◦ gram stain - process requires sequential use of crystal violet dye, iofine solution, alcohol solution, and safranin dye ◦ gram-positive - by violet dye, appears dark purple under microscope ◦ gram-negative - do not hold violet, appear pink to red need for oxygen ◦ aerobes - bacteria that require oxygen to grow ◦ anaerobes - bacteria that grow in the absence to oxygen and are destroyed by oxygen ◦ faculative anaerobes - organisms that can grow in the presence of oxygen or absence of oxygen capsules - protective layer that covers the cell wall. bacteria with capsules enhance its ability to resist the body's defence mechanisms. the capsule may also prevent antibiotic agents from affecting the bacteria spores - bacteria that are highly resistant. bacteria remain alive in spore form but are inactive. spores represent the most resistant forms of life known they can survive extreme heat and dryness and even the presence of radiation. Protozoa - consists of single-cell organisms that have complex internal structure, either free living or parasites. they live in water and organic material with out a rigid cell wall. can be found in freshwater and marine habitats and in moist soil. thick cell walls prevent them from drying; cysts are viable protozoa outside hosts Fungi - organisms such as: mushrooms, yeasts, molds oral candidiasis - caused by candida albicans, all forms are considered opportunistic infections. Viruses - much smaller than bacteria. despite tiny size, many viruses are fetal. viruses can live and multiply ONLY INSIDE an appropriate host cell. viruses invade then replicate then destroy host cell and the virus is then released into the body specificity - must be specific (preference) for particular cell types to replicate latency - dormant state of host cell known as provirus. then can be reactiviated in the future to produce additional infective viral particles. treatment of viral diseases - viruses cause many clinically significant diseases in humans. most viral can only be treated symptomatically. cannot be destroyed by antibiotics. viruses are capable of mutating allowing it to survive longer transmission of viral diseases ◦ direct contact ◦ insects ◦ percutaneous injury ◦ blood transfusion ◦ contaminated water or food ◦ inhalation of droplets expelled by coughing or sneezing Viruses in the environment - can be destroyed easily in the external environment. widely used chemicals are bleach, iodine, phenol and formaldehyde effectively destroy viruses on surfaces and objects. however are toxic internally. Rickettsiae short, nonmotile rods that normally live in the intestinal tract of insects like lice, fleas, ticks and mosquitoes organisms are very small and require host cell to reproduce Algae typically in nonflowing aquatic plants and can range from microscopic to larger multi cells organisms. can appear green/ yellow or brown/red. algae do not produce human diseases. Viral Diseases "Perfect parasites" Viral Hepatitis - 5 types Hepatitis A - source is fecal-oral, route of transmission is fecal oral, not chronic, prevention through vaccine Hepatitis B - source is blood and bodily fluids, route of transmission percutaneous and mucosal tissues, is chronic, prevention through immunization Hepatitis C - source is blood and bodily fluids, route of transmission percutaneous and mucosal tissues, is chronic, prevention is to preform blood donor screening; modify risky behaviour Hepatitis D - source is blood and bodily fluids, route of transmission is percutaneous and mucosal tissues, is chronic, HBV vaccine Hepatitis E - source is fecal-oral, route of transmission is fecal-oral, non chronic, prevention is ensure safe drinking water Human Immunodeficiency Virus (HIV) - blood borne infection, where the body's immune system breaks down. AIDS is causes by HIV. HIV infects special T-cells. T-cells have special receptors on their surface and are primarily responsible for immunity. as T-cells die due to HIV, the body cannot fight infections. HIV is spread through sexual contact and by sharing needles. HIV can be transmitted to fetus in urtero Herpesvirus Herpes simplex virus (HSV) ◦ type 1 - causes primarily oral lesions ◦ type 2 - causes primarily genital lesions Herpes Zoster virus (HZV) - causes herpes zoster = chickenpox and shingles Cytomegalovirus (CMV) - normally latent (does not cause disease) may become active when immune system is damaged; once active; highly contagious and is transmitted through most body fluids Epstein-Barr Virus (EBV) - causes infectious mononucleosis and burkitt's lyphoma, which is a malignancy of the lymph tissues West neil virus - common in Africa, West Asia, and Middle East, virus carried by mosquitoes, affect nervous system, causing inflammation of brain and spinal cord, symptoms are fever, headache, tiredness, aches, and rashes sometimes. H1N1 Flu virus (swine flu) - respiratory disease of pigs. spreads easliy from person to person. contaminated droplets from a cough or sneeze can be on surfaces, maticulous hand hygiene and H1N1 vaccine help prevent disease. Ebola virus - rare but fetal virus causes bleeding inside and outside body. ebola is spread through direct contact of broken skin or mucous membrane with blood and bodily fluids. person is not considered contagious unless symptoms present. Guidelines for Dental professionals on the Ebola virus - person cannot have dental treatment until 21 days after their arrival back to north america and without symptoms Zika Virus - spread to people through bite of an infectious aedes species mosquito. Zika can spread from mother to fetus, which lead to serious birth defects to the brain called microcephaly. no vaccine to prevent disease. SARS-CoV2 "Covid-19" - spread person to person through droplets when infected person breaths, talks, coughs or sneezes. virus originated from an animal and mutated to infect humans. Symptoms vary and can appear within 2-14days after exposure. Bacterial Diseases occurs when a pathological or harmful strain of bacteria enters the body and causes an illness. can infect any area of the body by reproducing and emitting toxins that damage the body. bacterial disease cause many lifethreatening complications are are usually contagious. Tuberculosis - caused by M. tuberculosis attacking the lungs but can damage kidney, spine and brain. spread through air when person talks or coughs or sneezes. TB is a Latent disease and is the leading cause of death from infectious disease worldwide. TB kill time is the bench mark for surface disinfectants Legionnaires Disease - caused by legionella pneumonphila and is responsible for 2 acute bacterial diseases. pontiac fever - causes acute flu-like symptoms legionnaires disease - transmitted through areoslization and aspiration of contaminated water Tetanus "lockjaw" - extremely dangerous often fetal disease caused by spore forming bacillus found in soil, dust, or animal or human feces. usually introduced through a wound or break in skin. organisms that cause tetanus produce severe muscle spasms and rigidity. prevented by vaccine. Syphilis - STD by Treponema pallidum spirochete. fragile outside body, direct cross-infection may occur during dental procedures through contact of lesion. stage 1 is characterized by presence of painless ulcerating sores known as chancre which is infectious on contact stage 2 is also infectious and immediate infection may occur through contact with an open sore. ◦ split papules at corner of mouth ◦ grayish-white moist mucus patches ◦ generalized measles-type rash, pox like pustules, oozing sores, hair loss Methicillin-Resistantt Staphylococcus Aureus MRSA - resistant to some antibiotics throuhg over use of penicillin. common bacterium that is caried on skin or in the nose of healthy people. about 30% of world pop carry this bacterium. always maintain good hand hygiene never squeeze or try to drain any sore keep wounds covered until it has healed do not share personal items such as towels, razors, sheets, and clothes Prions new and separate class, different from bacterium, fungi and viruses and all other known pathogens. defined as small proteinaceous infectious particles prions refer to abnormal pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal proteins found in the brain. prions change the shape of normal proteins inhibiting usual functions Diseases from prions are ◦ Cretzfeldt-Jakob disease ◦ Alzheimer disease Chapter 19 - Disease Transmission and Infection Prevention Chain of Infection - each link is a condition that MUST be present for infection or disease to occur. A break anywhere in the chain and you break infection process. infectious/ pathogenic agent - identification of agent; virus, fungus, bacterium, protozoan reservoir - stay healthy, sterilization, disinfection, water asepsis; saliva, blood, feces, water, environment animals, insects portal of exit - hand hygiene, barriers, minimize spattering, waste containment; secretions, excretions, droplets, aerosols mode of spread - hand hygiene, surface barriers, gloves, masks, aspectic technique; direct contact, droplets, sterilization, disinfection, clothing, eyewear; indirect contact, airborne portal on entry - gloves, eyewear, clothing, masks, aseptic technique; inhalation, ingestion, mucous membranes, broken skin susceptible host - immunizations, manage underlying diseases; person at risk Course of Infection - infection can flow a different course depending on the pathogen and a person's immune system response to host acute infection - symptoms often severe and usually appear soon after initial infection occurs. acute infections are of short duration. chronic infection - microorganism is present for a long duration; some presist for life. a person may be a carrier but be asymptomatic. latent infection - a persistent infection which symptoms "come and go" opportunistic infection - caused by normally non-pathogenic organisms in individuals whose resistance is decreased or compromised. Common in pts with autoimmune diseases or diabetes and an elderly persons. The Immune System Naturally acquired - occurs when a person is recovering from a contracted disease and recovered; when the body was fighting an invading pathogen and formed antibodies to provide future resistance. ◦ active immunity - the body of the host is actively involved in the process ◦ passive immunity - fetus receives antibodies from mother's placenta, passive because antibodies were acquired from outside source artificially acquired immunity - via immunization and vaccination Disease Transmission in the Dental Office Patient to Dental Team ◦ most common route through direct contact ◦ droplet infection affects mucous surfaces of eyes, nose, and mouth ◦ indirect contact can occur when team member touches contaminated surface or instruments. Cuts or punctures of contaminated needles, burs or instruments ‣ gloves ‣ handwashing ‣ masks ‣ face shields and goggles ‣ hair coverings ‣ dental dams ‣ HVE ‣ Pt mouth rinses ‣ air filters Dental Team to Pt ◦ rare if safety precautions are followed ‣ mask ‣ gloves ‣ face shields and goggles ‣ handwashing ‣ immunization Pt to Pt - by contamination of instruments used on one pt then transferred to the next ◦ infection control measures help prevent ‣ instrument sterilization ‣ surface barriers ‣ handwashing ‣ gloves Dental office to community ◦ microorganisms leave dental office and enter community by contaminated impressions sent to laboratory. From dental team members clothing, hands, hair ‣ handwashing ‣ removal of PPE ‣ wearing hair coverings ‣ disinfecting impressions and contaminated equipment community to dental office to pt ◦ municipal water Infection control program hand hygiene - handwashing, use of antiseptic hand rub, and surgical hand antisepsis Personal Protective Equipment (PPE) - goggles, face shields, masks, gloves, closetoes shoes easily wipeable. Protective clothing - lab coat with cuff sleeves and high neck line or gowns Mask types and functions ◦ level 1 - minimal fluid, spray, and aerosols generated ◦ level 2- low amounts of fluid, spray and aerosols generated ◦ level 3 - "surgical" moderate to heavy amounts of fluid, spray and aerosols generated. Chapter 20 - Principles and techniques of Disinfection Disinfection Processes During dental treatment surfaces are likely to become contaminated with saliva or aerosol-containing blood and saliva. Frequently touched surfaces can act as reservoirs for microorganisms. Studies have shown these microorganisms can survive on environmental surfaces for different lengths of time. Safest approach is to assume everything is contaminated with infectious material Environmental Infection Control CDChas guidelines for household and clinical surfaces ◦ clinical surfaces - directly contaminated by direct spray or splatter generated during dental treatment or by contact of gloved surfaces ◦ household surfaces - floors, walls, sinks with much lower risk of disease transmission Clinical Contact Surfaces - touch and transfer surfaces should be barrier protected to make for easy pt turn over and wipe down quicker. ◦ touch surfaces - directly touched and contaminated during treatment; surfaces are dental light handles, dental unit cords, chair switches, chairside computers, pens, containers of dental materials, and drawer handles ◦ transfer surfaces - indirectly touches but are still contaminated by instruments; surfaces are instrument trays, handpeices, air/water syringe, and suction receptors and radiograph equipment ◦ splash, spatter, and droplet surfaces - considered housekeeping surfaces, not in actual contact with members of dental team and contaminated instruments/supplies. examples are floors, sinks, and walls Surface Contamination prevent surface from becoming contaminated by use of surface barriers ◦ advantages: protects surfaces, prevents contamination, less time consuming, reduces handling and storage of chemicals, provides pt with visual of cleanliness, does not damage equipment ◦ disadvantages: adds plastics to environment ◦ may be more expensive than precleaning and disinfecting, requires a variety of shapes and sizes, may become dislodged during treatment preclean and disinfect the surfaces between pts ◦ advantages: may be less expensive than surface barriers, does not add plastic to environment, some dentists do not like the appearance of surface barriers ◦ disadvantages: requires lots more time to be done properly, not all surfaces can be adequately precleaned, over time some chemical s are distructive to dental equipment, no method to determin whether microbes have been removed or killed, some disinfectants must be prepared fresh daily, chemicals are added to environment upon disposal smooth hard surfaces that are easy to wipe keep clear grooved surface barrier Precleaning and disinfection although no cases of cross contamination are linked to dental treatment. cleaning and disinfecting of these surfaces are an important component of an effective infection control program. Precleaning cleaning before disinfecting - removal of bioburden. if a surface is not clean it cannot be disinfected precleaning techniques work best on smooth easily accessible surfaces Disinfecting intended to kill disease-causing microorganisms that remain on surfaces after percleaning. spores are not killed during the disinfection procedure disinfectant= chemicals applied to inanimante objects is counter and dental chair antisecptic = antimicrobial used for living tissue ie hands terms used for disinfecting process precleaning = reducing the number of microorganisms that are present by physically removing debris disinfection = process that kills disease-causing microorganisms but not necessarily all microbial life low-level disinfection = ineffective against M. tuberculosis and should only be used in the dental office for housekeeping purposes intermediate level disinfection = inactivates M. tuberculosis and destroys less- resistant organisms such as hep B and HIV high level disinfection = process that kills some but not all bacterial endospores and inactivates M. tuberculosis sterilization = process that inactivates all microbial life, including spores, bacteria, viruses, and fungi. Disinfectants EPA is responsible for registering and regulating disinfectants and sterilants according to chemical classification in dentisry only hospital grade disinfectants with tuberculocidal should be used to disinfect dental treatment areas sporicidal = capable of killing spores virucidal = capable of killing viruses fungicidal = capable of killing fungi Iodophors - EPA intermediate level disinfectant works within 5-10 mins. inactivated by hard water synthetic phenol compounds - EPA intermediate level disinfectant with borad spectrum activity; kills wide variety of microbes sodium hypoclorite - bleach no longer used in dentistry but still classified as intermediate level disinfectant alcohol - ineffective at removing bioburden therefore not used in dentistry Immersion disinfectants glutaraldehyde = liquid sterilant Chapter 21 - Principles and Techniques of Instrument Processing and Sterilization Sterilization techniques instrument processing involves much more than sterilization. proper processing of contaminated dental instruments is a 7 step process 1. transport - transport contaminated instruments to the processing area in a manner that minimizes the risk for exposure to persons and the environment. Use of proper PPE and a rigid leak proof container 2. Cleaning - clean instruments with a hands free, mechanical process such as an ultasonic cleaner or instrument washer. if instruments cannot be cleaned immediately, use a holding solution like glutaraldehyde 3. Packaging - wrap/ package instruments in appropriate materials. place a chemical indicator inside the package(integrator) with instruments. if a process indicator is not present on the outside of the package place an external indicator on outside of package. 4. Sterilization - load sterilizer accourding to instructions. label packages. do not over load sterilizer. place packages on their edge in single layers or on racks to increase circulation to the steilizing agent. allow packages to cool before removing from sterilizer and handling. 5. Storage - store instruments in a clean, dry environment tat maintains integrity of the package, rotate packages so that the oldest sterilization dates will be used first 6. Delivery - delivery packages to point of use in manner that maintains sterility of instruments until they are used. inspect each package for damage. open package aseptically 7. Quality - an effective quality assurance program should incorporate training, record keeping, maintenance, and use of biologic indicators. Classification of Instruments and Practices Critical - function: touch bone or penetrate soft tissue, intra oral use, disease transmission rick very high, procedure sterilization. Ex) surgical, forceps, scaples, bone chisels, scalers, burs semi-critical - function: touch mucous membranes but will not touch bone or penetrate soft tissue, intra oral use, disease transmission risk moderate, procedure: sterilization or high level disinfection. Ex) mouth mirrors, amalgam condensers non-critical - contact only with intact skin, no intra oral use, Procedure: intermediate to low levell disinfection/ basic cleaning. Ex) external dental x-ray head Instrument processing area = uni directional with signs of direction and if dirty, contaminated, cleaned, sterile and sterilization Ultrasonic cleaner testing ultrasonic cleaner with 5x5 lightweight aluminum foil Methods of sterilization steam autoclave ◦ advantages: short duration, no corrosion, instruments dry quickly ◦ Disadvantages: damages some rubber and plastic items, requires use of distilled water, may rust nonstainless steel instruments or burs, cannot use closed containers unsaturated chemical vapour ◦ advantages: short time, good penetration of steam, commonly used in dental offices ◦ disadvantages: instruments must be dry, damages some plastic and rubber items, requires special solution and good ventilation, cannot sterilize liquids, cannot use closed containers, cloth wrap may absorb chemicals Dry heat oven type(static air) ◦ advantages: no corrosion, can use closed containers, items are dry after cycle ◦ disadvantages: long sterilization time, instruments must be pre-dried, damages some plastic and rubber items, cannot sterilize liquids Rapid heat transfer(forced air) ◦ advantages: very fast, no corrosion, items are dry after cycle ◦ disadvantages: damages some plastic and rubber items, instruments must be pre-dried, cannot sterilze liquids Sterilization monitoring physical chemical - external and interal, process integrators or multi-parameter indicators= into each packet, respond to combination of pressure, temp, and time; process indicators or single-parameter indicators = reached certain temp. biological = spore testing Handpiece sterilization flushing - attach pressurized handpiece to cleaner to where all debirs will be flushed out sterilizing - steam only Chapter 22 - Regulatory and Advisory Agencies Government Agencies Food and drug administration FDA ◦ regulates manufacturing and labeling of medical devices Environmental protection agency EPA ◦ regulates safety and effectivness of disinfectants and waste management of materials Public health agency of Canada PHAC roles: ◦ promote good physical and mental health ◦ prevent and control chronic diseases and injuries ◦ prevent and control infectious diseases ◦ prepare for and respond to public health emergencies Occupational safety and health administration OSHA ◦ regulates workplace safety and health with hazard communication standards ◦ OSHA inspects ‣ when an employee or Pt complaint is made ‣ randomly in an office with 11 or more employees ‣ on request of the dentist for a consultation visit ◦ OSHA hazard communication ‣ staff training ‣ how chemicals are handled in the office, including information on all labeling and safety mesasures ‣ how to respond to chemical emergencies such as spills or exposures Chapter 23 - Chemical Waste Management Exposure to chemicals inhalation of chemical vapour absorption of chemical through skin ingestion of chemical (eating or drinking) Classification of waste General waste ◦ examples: paper towel, paper mixing pads, empty food containers ◦ handling reqs: discard in covered containers made of durable materials such as plastic or metal Hazardous waste ◦ examples: waste the presents a danger to humans or to the environment (toxic chemicals) ◦ handling reqs: follow your specific, local regulations Contaminated waste ◦ examples: waste that has been in contact with blood or other bodily fluids(used barriers, pt napkins) ◦ handling reqs: generally disposed with general waste Infectious or regulated waste (biohazardous) ◦ examples: waste capable of transmitting an infectious disease ◦ handling reqs: follow local regulations blood and blood soaked materials ◦ examples: blood or saliva that can be squeezed out, or dried blood that may flake off of an item ◦ handling reqs: containers for all 3 types of infectious waste must be labelled biohazardous Pathogenic waste ◦ examples: soft tissue and extracted teeth ◦ handling reqs: follow local regulations sharps ◦ examples: contaminated needles, scalpel blades, orthodontic wires, endodontic instruments ◦ handling reqs: closable, leak proof, puncture resistant containers; containers should be colour coded red and marked with biohazard symbol, container should be located close as possible to work area Regulated waste terminology infectious waste ◦ medical waste that could be capable of causing an infectious disease ◦ Description: ‣ liquid or semi-liquid blood, saliva, or other potentially infectious materials (OPIM) ‣ items contaminated with blood or OPIM that would release these substances in a liquid or semiliquid state if compressed ‣ items that are caked with dried blood or OPIM and are capable of contaminating during handling Pathogenic waste ◦ medical waste that can be contaminated and cause infectious disease ◦ description: ‣ body material derived from biopsies or surgical procedures, such as gingival tissue, bone, and extracted teeth Contaminated sharps ◦ waste that can be contaminated and pose a threat to humans ◦ description: ‣ Needles, glass carpules, burs, acid etch tips, file, blades, orthdontic wires, etc Hazardous waste ◦ waste that poses threat to humans or the environment ◦ description: ‣ usually refers to toxic chemicals or materials such as amalgam, lead foil and certain disinfectants general waste ◦ description: ‣ non-hazardous, non regulated waste Chapter 24 - Dental Unit Waterlines Chapter 25 - Ergonomics