unit 1 microB and infectious disease

• Level I Certified Dental Assistant Skills (CDA)

  • Preparation of the treatment/clinical area
  • Cleaning and sterilization of instruments and hand pieces
  • Passing instruments to the dentist or hygienist (single- and two-handed technique)
  • Proper use of High Volume Evacuator within the Oral Cavity
  • Preparation of Restorative Materials
  • Perform simple laboratory procedures such as the pouring and trimming of study models
  • Maintains supplies and equipment (stocks and replenishes supplies)
  • Monitors inventory
  • Assesses emergency situations, aware of emergency protocols, knowledge of First Aid and CPR
  • Assists in maintaining emergency drug kits
  • Ability to interpret Material Safety Data Sheets
  • Conducts spore/biological indicator tests
  • Recording data on patients' record or chart as directed by the DDS
  • Patient and community education on oral health (extra-oral)
  • Other extra-oral duties as required by the dentist
  • Instruction in care and maintenance of pre-fitted appliances
  • Expose, process, and mount radiographs as specified by HARP
  • Obtains vital signs
• Level II Dental Assistant Skills

  • Mechanical polishing of the coronal portion of the teeth
  • Placement and removal of rubber dam
  • Taking of preliminary impressions of teeth for study models
  • Topical application of anti-cariogenic agents
  • Oral hygiene instruction with an intra-oral component
  • Dietary counseling relative to dentistry
  • Application of materials topically to prepare the surface of the teeth for pit and fissure sealants
  • Application of pit and fissure sealants
  • Application of topical anaesthetics
  • Application of desensitizing agents
  • Whitening of the coronal portion of the teeth using tray-based systems; including application of a liquid dam if required for these tray-based systems
  • Polishing restorations
  • Oral irrigation
• Dental Assisting Program Learning Outcomes

  • Maintain client and personal safety in the practice environment.
  • Contribute to the development of a comprehensive client profile by using a variety of data collection methods in collaboration with the client and other health professionals and in compliance with privacy legislation.
  • Contribute to the development of a comprehensive plan for oral health services and programs in collaboration with the client and other health professionals.
  • Provide oral health services and programs, as identified in the comprehensive plan as permitted within the scope of practice.
  • Contribute to the evaluation and reporting of appropriate aspects of the oral health services and programs by using a variety of sources including the client profile.
  • Act in a professional and competent manner.
  • Maintain client records and manage office procedures in compliance with relevant legislation and regulations.
• Course learning outcomes


  • Explain the process and prevention of infectious disease transmission in the dental setting.
  • Describe the methods of sterilization and maintenance of equipment in the dental environment meeting current infection control guidelines.
  • Describe the technique and elements of oral evacuation, safe instrument transfer, administration of local and topical anaesthetic, rubber dam placement, and hand and rotary instruments as it relates to the role of dental .
  • Outline the role of the Professional Dental Assistant in Ontario.
• Microbiology is the study of microorganisms, micro meaning small and bio means living organisms – the study of small life forms. Understanding microbiology can help to prevent the transmission of disease from person to person.
• Which necessitates our knowledge about infection control
• Microorganisms are


  • more beneficial than harmful to humans
  • Harmful activities of microorganisms include: spoiling food, occluding water lines, causing disease
• Uses of bacteria


  • modern sewage treatment, manufacture of vinegar, vitamins, alcohol, antibiotics, cheese/yogurt, fertilizer
• Fungi known as yeast is used to make bread rise and for beer production
• Louis Pasteur

  • Known as the "Father of Microbiology"
  • He was instrumental in saving the French wine industry by showing that vats of spoiled wine contained acid-producing bacteria and heating the grapes would reduce microorganisms
  • This process was called "pasteurization"
  • Responsible for preparing the 1st vaccine for rabies
• Discovery of rabies vaccine by Louis Pasteur, 1885.
• Non Pathogenic microorganisms


  do not produce human illness
• Pathogenic microorganisms


  are disease producing
• Major groups


  • Bacteria
  • Algae
  • Protozoa
  • Fungi
  • Viruses
  • Prions
• Viruses


  • Smallest of the microorganisms
  • May cause fatal disease
  • Need host
  • Destructive
• Three basic shapes of Bacteria

  • cocci (spherical)
  • bacilli (rod shaped)
  • Spirochetes (curved or spiral)
• Cocci


  • Reproduce by dividing in two.
  • Cocci that form chains are called streptococci (causes strep throat, tonsillitis, pneumonia, endocarditis).
  • Cocci that form clusters are staphylococci (cause skin infections and pneumonia).
• Bacilli


  • A disease caused by bacilli is Tuberculosis (Tb).
  • May be latent or active (only active can be transmitted).
  • One of the deadliest and common major infectious diseases today.
• Spirochetes


  Causes Lyme disease (caused by an infected tick), and syphilis.
• Types of Bacteria


  • Aerobic bacteria - requires oxygen to grow
  • Anaerobic bacteria - grow in the absence of oxygen and are destroyed by oxygen
  • Facultative anaerobes - can grow with or without presence of oxygen
• Pathogenic bacteria usually grow best at temperature of 98.6 degrees (37 degrees Celsius) in a moist, dark environment
• Shapes of Bacteria


  • Spherical (cocci)
  • Rod (bacilli)
  • Spiral (spirochetes)
• Disease producing microorganisms


  are referred to as Pathogenic
• CAPSULES


  • forms a protective layer covering cell wall
  • these bacteria are virulent – may resist body's defense mechanisms and antibiotics
  • Example: Streptococcus Mutans causes Dental Caries (cavities)
• SPORES


  • Under unfavorable conditions, some bacteria change into a highly resistant form called SPORES
  • Spores are the most resistant form of life
  • Survive extreme heat, dryness, chemicals and radiation
• Rickettsiae (Bacilli-rods)


  • Require a host to reproduce
  • Carried by ticks, fleas, lice, mosquitoes
  • Cause Typhus and Rocky mountain spotted fever
• Algae


  • Single or multiple cell organisms such as seaweed or kelp
  • Most do not produce disease
  • Found in freshwater and marine habitats
• PROTOZOA


  • Single-celled organisms
  • Found in freshwater and marine habitats and moist soil
  • Most do not produce disease
  • May survive as cysts for long periods of time outside of their host
  • Can be responsible for intestinal infections in humans
• FUNGI


  • organisms such as mushrooms, yeasts and molds
  • no chlorophyll
  • Candida is a common yeast found in the oral cavity (oral candidiasis)
  • oral candidiasis is caused by the yeast Candida albicans
  • Often seen as an opportunistic infection
  • Treated with an antifungal such as Nystatin
• Viral Diseases


  • Measles, mumps, colds, SARS, West Nile, encephalitis, herpes, HIV, chicken pox, hepatitis, Zika , H1N1, Covid-19
• VIRUSES


  • Smallest of the microorganisms
  • May cause fatal disease
  • Need host
  • Destructive
  • Cause of many newer serious diseases
• Viral Diseases


  • viruses can live and multiply only inside an appropriate host cell
  • Process- virus invades host cell, replicates and then destroys the host cell so viruses are released into the body
  • Have specificity (preference) for particular cell types in order to replicate (example: hepatitis infects only liver cells)
• LATENCY


  • Some establish a latent (dormant) state in host cells and later reactivate
  • Some can cross the placenta and infect the fetus (HIV)
• Treatment - viruses cannot be destroyed by antibiotics
• Transmission of Viruses


  • direct contact
  • insects
  • blood transfusion
  • contaminated food and water
  • inhalation of droplets – coughing or sneezing
• Viruses can be easily destroyed in the external environment (on surfaces or objects) with chemical disinfectants or heat
• PRIONS


  • Abnormally structured protein with no RNA or DNA
  • Rare in Humans, affect brain
  • May be dormant for a long time
  • Highly resistant to heat, chemicals and irradiation
  • No treatment or vaccine available
  • Linked to Mad Cow, Creutzfeldt- Jakob disease, possibly Alzheimer's
• Acute


  often severe and of short duration like the common cold
• Chronic


  long duration. Microorganisms are present for a long time and sometimes for life. Person may be asymptomatic and carry the disease such as in Hepatitis C.
• Latent Infection


  Symptoms may come and go (herpes). Virus enters the body causes the original infection and lies dormant until the immune system is weaker then recurs.