303 - prevention and control of infection. Flashcards
What is pathology?
Study of disease - disease is condition of suffering from illness.
What are many disease caused by?
Contamination of body cells by microscopic living organisms.
What is microbiology?
The study of different microorganisms and how they live/function.
What are pathogens?
Organisms that have capability of producing a disease.
What is a non-pathogen?
Organisms that do not cause disease.
What are the 3 main groups of pathogenic microorganisms?
- Bacteria
- Viruses
- Fungi
What is bacteria?
- Microscopic single cell organism
- Survives as inactive spore when it can’t grow/reproduce.
What is a virus?
Ultramicroscopic organism that lives within cell wall of other organisms.
What is Fungi?
Type of microscopic plant organism that grows across cells and tissues.
What are prions?
- Not living microorganisms
- Type of special infectious protein that can cause disease.
What disease’s has prions caused?
‘Mad cow disease’ and its variant, Creutzfeldt-Jakob disease (CJD).
Types of bacteria, and their shape?
- Cocci: circular microorganism. Colonies in cluster are staphylococci, chains are streptococci.
- Bacilli: rod shaped with pointed ends, rounded end is Lactobacilli.
- Spirochacetes: spiral shaped like helix.
How do you remove risk of bacterial infection on dental instruments?
- Sterilise instruments
- Use once and discard if single use.
What are anaerobic bacteria?
Bacteria in oral cavity that has adapted to exist in low oxygen level - deep in caries or in a pocket.
What are antibiotics taken for?
- To kill bacteria causing severe illness
- Kills some helpful bacteria naturally found in body.
What are bactericidal agents?
Chemicals used to clean externally (work surfaces) to kill bacteria.
What are bacteriostatic agents?
Chemicals used to clean externally, do not kill bacteria but prevent them reproducing and multiplying.
What is Streptococcus mutans?
Initial infective bacterium found in dental caries.
What is Lactobacillus?
Later colonisation of established carious lesion as deeper tooth tissue becomes infected.
What are
- Actinomyces
- P gingivalis,
- Prevotella intermedia
- Treponema denticola
- Fusobacterium nucleatum
- Campylobacter rectus
Periodontal disease, bacterial infection of supporting structure of teeth.
What is staphylococci?
Skin boils and gingival boils, impetigo.
What is Bacillus fusiformis and Borellia vincentii.
ANUG (acute necrotising ulcerative gingivitis) - periodontal infection when OH is poor.
Where do viruses live?
Within cells of other organisms.
What do viruses exist as?
A protein capsule that contains chemicals a virus needs to reproduce.
What is Hepatitis A, B, C?
A various inflammatory liver disease.
What is HPV (human papillomavirus)
Linked to oral cancer
What is Herpes varciella?
Chickenpox, affects area supplied by trigeminal nerve and torso.
What is HIV (human immunodeficiency virus)
AIDS, blood borne and fatal viral infection.
What is herpes zoster?
Shingles, painful blistering skin rash
What is Herpes simplex type 1?
‘cold sores’: blister lesions on lips, highly infectious in initial stage if touched.
What is Epstein-Barr virus?
Glandular fever, swollen lymph glands.
What is paramyxovirus?
Mumps, viral infection of parotid salivary glands.
What is Coxsackievirus?
Hand, foot and mouth disease - painful blistering in oral cavity and palms of hands/soles of feet.
Where do fungi live?
The outer surface of the body like, skin, oral cavity lining, nails and surface of eye.
What is the main fungal infection in dentistry?
Candida Albicans
Appearance of acute oral candidosis (oral thrush)
removable white film, underlying red sore patches on soft tissue of oral cavity.
Chronic oral candidosis (denture stomatitis)
- beneath denture and removable appliance
- reddened, painless area under palatal section of appliance
- Raised moisture level beneath appliance and poor appliance hygiene.
Angular chelitis
Candida infection that involves angles of mouth, appear as localised area of inflamed, cracked skin.
What are the effects of disease on the body?
- infection/inflammation
- ulceration
- oral white/red patches
- formation of cyst
- formation of tumor
- congenital/developmental defect
What are the five signs of inflammation?
- heat
- swelling
- pain
- redness
- loss of function
What is infection?
The invasion of body cells by pathogens resulting in a inflammatory response.
Examples of dentally relevant infections:
- Dental caries
- Periodontal disease
- Herpes simplex
What is stomatitis?
General inflammatory condition affecting oral cavity.
Who is usually affected by stomatitis?
- Elderly and denture wearers
What is an ulcer?
- A shallow break in the skin or mucous membrane
- Leaves a raw, painful circular base that may bleed
Recurrent ulcerations
Affects 20% population, patient may have nutritional deficiencies
Ulceration due to systemic disease
diseases that affect digestive system exhibit oral ulceration
- Crohn’s disease
- Ulcerative colitis
- Coeliac disease
- Inflammatory bowel disease
What are the causes of oral white patches?
Oral candidosis
What is Leukoplakia?
a white patch with no obvious local cause
premalignant
associated with smoking/heavy alcohol intake
What is Erythroplakia?
a red patch on oral mucosa
sinister sign of premalignancy of soft tissue
What is a cyst?
an abnormal sac of fluid within body tissue developed over period of time
Examples of dentally related cysts?
- Dentigerous cyst: around impacted/unerupted tooth
- periapical cyst: around tooth apex
- trauma to minor salivary gland = mucocele
What is a tumour?
a swelling within the body tissue due to uncontrolled and abnormal growth of body cells.
What is a benign tumour?
A swelling that causes no harm other than displace its surrounding structures.
What is a malignant tumour?
A swelling that invades and damages its surrounding structures.
Examples of dentally relevant tumours?
- squamous cell carcinoma
- osteosarcoma of mandible/maxilla
- salivary gland tumours
- lymphoma
What is a congenital/developmental defect?
An inherited condition or genetic mutation that produces illness or condition present at birth.
Examples of dentally relevant defects
- cleft lip/palate
- congenital absence of some teeth (hypodontia)
- defect of tooth formation (amelogenseis imperfecta)
What are the bodies 3 lines of defence against attack by pathogens?
- Skin and mucous membranes are physical barriers
- Surface secretions onto skin or mucous membranes dilute and neutralise the pathogen e.g. saliva, sweat and tears.
- inflammatory response within body tissues if skin/mucous membranes are breached
Who is most likely to suffer when attacked by pathogens and why?
- Elderly: function of body cells not as efficient
- Young children: immune system not functioning fully/not developed acquired immunity to certain pathogens
- Debilitated: immunocompromised patients as they have underlying illness so immune system can’t fight pathogen well.
In the dental workplace, how can pathogen microorganisms breach the skin or mucous membrane and gain entry?
- Direct contact: bodily fluids like saliva, blood, vomit.
- Airborne droplets: sneezing, coughing or spitting.
- Direct entry: damaged skin, or cuts, grazes.
Aerosol spray: created during use of dental handpieces and water sprays - spray blood/saliva into atmosphere. - inoculation injury: piercing of skin with contaminated instrument like needlestick injury.
How does tissue repair after an inflammatory response?
New leucocytes remove damaged/dead tissue and lay temp layer of repair cells.
What is natural immunity?
present from birth by being randomly inherited
What is passive immunity?
present from birth and inherited directly from mothers pool of antibodies/antitoxins
What is acquired immunity?
creation of necessary antibodies/antitoxins by leucocytes during initial pathogen attack. These remain in body for life.
Vaccination to produce acquired immunity
harmless dose of pathogen given to stimulate leucocytes to develop antibodies/antitoxins without actual disease developing.
What is a leuococyte?
white blood cells
what are erythrocytes?
red blood cells
What must dental staff be vaccinated against?
- Hepatitis B
- MMR
- Tuberculosis and whooping cough
- Poliomyelitis
- Diphtheria and tetanus
- Chickenpox (not naturally immune)
- Meningitis
How do you avoid infection by microorganisms?
- staff vaccination
- ppe during treatment and cleaning
- use of single use disposables
- correct decontamination/sterilisation of instruments
- correct cleaning of clinical area
- thorough hand washing
What are dental caries?
bacterial infection of hard tissue in tooth
what is periodontal disease?
bacterial infection of the gingivae and periodontal supporting tissues
what is oral thrush?
a fungal infection of the oral soft tissues
what is a periapical abscess?
bacterial infection of the tooth pulp, abscess forms at apex
what is a periodontal abscess?
a bacterial infection in a periodontal pocket causing abscess formation
what are aphthous ulcers?
ulceration of oral soft tissues not related to infection
what is herpetic ulceration?
viral infection of oral soft tissue causing ulceration
what is acute necrotising ulcerative gingivitis?
acute bacterial infection of gingivae causing ulceration
what is a dental cyst?
cyst formation associated with tooth, unerupted or erupted
what is an alveolar bone cyst?
cyst formation within jaw bone
what is periocoronitis?
acute bacterial infection of soft tissue associated with partially erupted tooth, especially lower third molars (8)
what is localised osteitis?
bacterial infection of bony walls of extraction socket (dry socket)
what is cellulitis?
bacterial infection spreading from tooth into surrounding deep soft tissue structures
what is a cleft palate?
developmental defect of palate where two bony halves don’t join completely during embryonic development
what is oral cancer?
malignant tumour that usually affects oral soft tissues initially, can spread to underlying tissues if not treated.
What parts of the body does oral cancer affect?
-lip
-tongue
-floor of mouth
-gingiva
oral soft tissues
What is the cancer that affects tonsils and oropharynx region?
oropharyngeal cancers
what is oropharyngeal cancer caused by?
majority by human papillomavirus (HPV)
what does oral cancer initially start as in soft tissues?
squamous cell carcinoma
tobacco habits
tobacco products contain chemicals that can cause cancer and are seen as risk factors e.g. betel quid
high alcohol consumption
alcohol is a solvent for carcinogens - easier entry into deeper layer of soft tissues.
what is a carcinogen?
substances that increase your risk of cancer
what makes you more at risk of squamous cell carcinoma?
smoking and drinking excessively
how is sunlight linked to squamous cell carcinoma?
it affects the lower lip in fair skinned people
what is the link between diet and squamous cell carcinoma?
diet low in fresh fruit and vegetables
genetics link to squamous cell carcinoma
some people are genetically predisposed to developing it
how does the dental team prevent oral cancer and improve survival rate?
- up to date with CPD and early detection of oral cancer
- soft tissue examination at every recall
- refer suspicious lesions appropriately
what should be raised suspicious if found during an examination?
-painless ulcer no obvious cause, failing to heal after 3 weeks
-presence of red or red/white patch more than 3 weeks
-growth of soft tissues producing lump more than 3 weeks
-persistent unexplained lump in neck
who do you refer to when you find something suspicious?
local oral and maxillofacial unit, urgent 2 week referral
what should the dentist consult with if patients admit tobacco use?
ASK: record smoking status
ADVISE: best way of quitting
ACT: build confidence, refer to stop
what is the general advice for pts who drink regularly and wish to seek help and advice?
-dont drink more than 14 units PW
-spread the 14 units over 3 days or more
-regular drinking increase risk
-try have several alcohol-free days
-pregnant women avoid drinking
what are the oral health effects from alcohol and tobacco use?
- develop oral precancerous lesions
- periodontal disease
- poor wound healing
- tendency to develop ‘dry socket’
- stained teeth
-halitosis - tooth erosion
- dental and facial trauma
what are the general health effects from alcohol and tobacco use?
- heart disease
- stroke
- respiratory disease
- other cancers e.g. throat, lung, stomach
what is herpes?
group of viruses that affect oral soft tissues
what is herpes simplex 1?
primary infection in childhood, acute inflammation of oral soft tissues (gingivostomatitis) - painful ulcers
what is herpes labialis?
recurrent condition occurs after initial primary herpes simplex, ‘cold sore’, occurs on lip
appear when stressed, had recent ‘cold’
what is herpes zoster?
shingles - occurs as reactivation of virus in patients previously affected by chickenpox
what area of body can shingles affect?
trigeminal nerve (face and oral cavity) and skin of torso
what is human immunodeficiency virus (HPV)
a virus that is the causative agent of fatal condition, AIDS.
what is oral candidiasis?
extensive fungal infection of oral cavity with heavy coatings of white ‘thrush’ lesions on tongue/palate
what is kaposi’s sarcoma?
characteristic tumour of AIDS sufferers - occur as purplish brown lesion on palate and skin
what is oral hairy leukoplakia?
oral white patch, distinct microscopic appearance on biopsy - premalignant
linked to HIV
what is diabetes?
disorder affecting pancreas characterised by concentration of glucose in blood resulting in inability of body cells metabolising glucose correctly
what is type 1 diabetes
insulin dependent
what is type 2 diabetes
non-insulin dependent
how does diabetes affect oral cavity?
xerostomia - cleansing and lubricating saliva reduced
poor wound healing - peripheral blood supply reduced
infection as peripheral vascular disease and peripheral neuropathy result in reduced blood flow
what is epilepsy?
electrical activity in brain becomes suddenly and temporarily disrupted, results in seizure
what side effect does the drug for epilepsy (Epilim) have?
gingival hyperplasia - gingival tissue overgrowth
what is bulimia?
an eating disorder where the sufferer follows periods of compulsive overeating and periods of self-induced vomiting/fasting
what are the oral effects of vomiting?
enamel erosion: severe pitting and enamel loss, vomit is acidic
soft tissue burns: acidic vomit causes burns
what is crohn’s disease?
chronic inflammatory disease, affects part of GIT, shows orally as ulcerations
what is ulcerative colitis?
chronic inflammatory disease, affects colon and rectal areas of GIT, shows orally as aphthous ulcers
what is coeliac disease?
absorption disorder of small intestines, intolerance to cereal protein gluten, shows orally as ulceration, glossitis and stomatitis
what are antibiotics?
drugs used to specifically fight against infection by bacteria
what are anaerobes?
bacteria that live in oxygen-poor areas
what are aerobic bacteria?
bacteria thrive of living in oxygen- rich environment
what are side effects of antibiotics?
nausea, vomiting, diarrhoea
what are the allergic reactions from antibiotics?
- sensitivity reactions to colour dyes used in capsulated antibiotics
- full anaphylaxis e.g. from penicillin’s
how do antibiotics interact with other drugs?
prevented from working properly or produce serious side effects
what is antibiotic resistance?
the overuse of antibiotics allows resistant strains of bacteria to evolve, these are not killed by usual antibiotics.
Bacteria becomes resistant over prolonged period or repeatedly - justify their use.
what antibiotics are recommended when a pt is suffering from an acute or chronic dento-alveolar infection or periodontal abscess.
amoxicillin
metronidazole
clarithromycin or erythromycin
how is amoxicillin given?
500mg 3x daily for up to 5 days
how is metronidazole given?
safe alternative to amoxicillin - 400mg 3x daily up to 5 days
how is clarithromycin/erythromycin given?
250mg 2x daily up to 5 days - safe alternative to penecillin
other than antibiotics, what operational measures are taken for ANUG?
scaling and appropriate oral hygiene instructions.
chlorhexidine mouthwash
what antibiotics are given for ANUG and pericoronitis?
metronidazole
amoxicillin
what measures taken for pericoronitis?
cleaning the area
irrigate with warm salt water
mouthwash (peroxyl)
why do some implant manufacturers recommend antibiotics during placement of implants?
to prevent:
postoperative infections
pain
peri-implantitis
what implants are given after implant placements?
amoxicillin: 2g taken (4 500mg capsules)
clindamycin: for pt allergic to penicillin, dose of 600mg ( 4 150mg capsules)
both taken 1 hour preoperatively
what are antivirals?
drugs used against infections caused by virus
what antivrial is given for herpes labialis? (coldsores)
aciclovir antiviral cream
apply to lesion 5x daily for 5-10 days
what are antifungals?
drugs used against fungal infections
what antifungal is given for infections causing oral thrush?
lozenges
pastilles
oral gel
what antifungals are prescribed as capsules?
fluconazole: difficult fungal infections
nystatin: oral suspension/lozenges
amphotericin: 10mg lozenges
miconazole: oral gel
what are analgesics?
drugs used primarily to relieve pain
should avoid during pregnancy
what are the frequently used analgesics?
paracetamol: has antipyretic properties - reduce body temp, can cause liver damage
ibuprofen: NSAID and analgesic, can cause stomach ulcers if used excess
aspirin: acts as anticoagulant CANT give after surgical procedures
principles of ‘chain of infection’
infection agent: cause of virus
reservoir: can be person/animal/plant - what pathogen of infectious agent attaches to
portal of exit: microorganism exits through coughing, sneezing, blood transmission, urinary tract
route of transmission: how pathogen passes from one to another e.g. direct/indirect/AGP transmission
portal of entry: when pathogen enters other hosts body through, eyes, nose, mouth
susceptible post: person at risk, risk depends on general health and immune system
what are the routes of transmission of infectious diseases?
direct
indirect
AGP (aerosol generating procedures)
what is direct cross infection?
person in direct contact with contaminated person
through sneezing, coughing, physical contact
what is indirect cross infection?
person that has never been in direct contact with person, infected through contaminated instruments or surfaces
what is aerosol generating procedures?
medical and patient care procedures that result in production of airborne particles.
how does pregnancy affect susceptibility to infection?
immune system protects mum and baby, works harder than usual
different parts are enhanced, some are not needed and are suppressed
balance to prevent infection
how does immunocompromised affect susceptibility to infection?
immune system is weak
e.g. someone with HIV, cancer patient
prone to getting pathogens
how does age affect susceptibility to infection?
immune system weaker
medical conditions - catch infections quicker
how does medical treatment/illness affect susceptibility to infection?
e.g. cancer affects immune system - risk of catching infections
cautious of where they go to not catch illness
what is the basic principle of infection control?
to assume that any patient may be infected with any micro-organism and can pose infection risk
why is medical history taken and updated every visit?
to identify majority problems
what is a carrier?
an individual who is infected by a micro-organism but shows no sign of disease, unaware of risk to others
how do dental staff apply good basic personal hygiene?
regular hand washing to remove microorganisms and reduce risk of cross-infection
how is good basic infection control achieved?
cover wounds with waterproof dressing
wear non-latex gloves
clear blood and bodily fluids using appropriate spillage kit
follow correct procedure for safe disposal of contaminated waste and sharps
what does best practice dictate that good general infection is achieved by?
up to date written infection policy in place
standard precautions used for all patients
correct cleaning of clinical area
correct cleaning/disposal of instrument/handpieces
validation, maintenance and testing of decontamination equipment
how is personal infection control followed by staff?
clinical staff vaccinated against HEP B
staff immunised against current common illnesses
follow correct hand-cleaning procedures
use all PPE appropriately
all inoculation injuries dealt with immediately
what does social cleanliness mean?
clean to a social acceptable standard for personal hygiene but not disinfected/sterilised
what does disinfection mean?
process used to kill or inactivate bacteria and fungi but not spores or some viruses
what does sterilisation mean?
process of killing all micro-organisms and spores to produces asepsis - using autoclaves
what does asepsis mean?
absence of all living pathogenic micro-organisms
what does decontamination mean?
combination of processes used to remove contamination from reusable items so they are safe for further use
what stages does decontaminate involve?
cleaning
disinfection
inspection
packaging
dispose of single-use items
sterilisation
transport
storage