Radiation/Infection Control Flashcards
Image Gently
The Alliance for Radiation Safety in Pediatric Imaging
National alliance with goal of decreasing radiation/being more aware of radiation in pediatrics
Millimeter-Wave Technology Unit
Airport security scanner
Uses non-ionizing radio-frequencies in millimeter wave spectrum to generate an image based on energy reflected from the body
Pregnancy and radiation
Some relationship between antepartum dental radiography and infant low birth weight
More radiation was associated with low birth weight of babies in one study
Many confounders (more periodontal disease, more infection, etc.)
Thought to be related to subclinical hypothyroidism (why ADA recommends thyroid collar for patients)
How are x-rays formed?
Electromagnetic radiation of penetrating power is produced by the bombardment of a substance (usually heavy metal) by a stream of high velocity electrons usually in a vacuum tube
Electromagnetic spectrum
X-rays have high frequency (less than gamma but above everything else)
High frequency = short wavelengths
Spectrum based on wavelength:
Radio > microwave > infrared > visible light > UV > x-ray > gamma
3 interactions of x-ray with matter
Coherent Scattering
Photoelectric absorption
Compton Effect
Compton effect
Some x-rays scatter off of the patient
Why staff should be 6 feet away from x-ray source when taking radiographs
X-rays that scatter lose energy
What percentage of the scattered photons formed during a dental x-ray exposure exit the patient’s head?
30%
Scattered photons travel in all directions
9% pass through without any interaction
Most radiosensitive cells
Those with high mitotic rate
Those that will undergo future mitosis
Cells with primitive differentiation
Deterministic effects
Response is proportional to the magnitude of the dose
Stochastic effect
The response is proportional with the frequency of the dose
Most related to dental radiography
Earth Radiation
Natural radiation is 3.6 mSv/year
83% of this is coming from natural sources (radon is the most, but also cosmic or terrestrial or food radiation)
17% is from artificial sources (medical radiation, of which dental is a very small proportion)
How much radiation is in a bitewing?
3.6mSv / 365 = 0.00986 mSv per day
One posterior bitewing is 0.005 mSv (with rectangular collimation) -> about 0.6 background radiation days
What is the best way to reduce radiation exposure?
Rectangular collimation
Reduces by 50%
Digital imaging versus film
Reduces dose of radiation compared to film
However, ease of retakes and increase in number makes this effect not as large
Dose reduction of digital versus F-speed film
0-50%
Handheld x-ray system
Designed to minimize user’s radiation dose
Doses for handheld system is less than wall-mounted system
Additional shielding efforts will not provide significant benefit nor reduce staff radiation dose
Justification for radiographs (overview)
Patient selection
Positive clinical signs/symptoms
Patient selection for radiographs
Patient selection is the most significant factor influencing per capita dose
Recommendations are subject to clinical judgment
Dentist should NOT prescribe routine radiographs at preset intervals for all patients
When should a dentist prescribe dental radiographs?
Only AFTER clinical evaluation
Radiograph prescription for a child with primary dentition - new patient
Individualized radiographic exam consisting of selected PA/occlusal views and/or posterior bitewings if proximal surfaces cannot be visualized or probed
Patients without evidence of disease and with open proximal contacts may not require a radiographic exam at this time
Radiograph prescription for a child with primary dentition - recall with high caries risk
Posterior bitewing exam at 6-12 months if proximal surfaces cannot be examined visually or with a probe
Radiograph prescription for a child with primary dentition - recall with low caries risk
Posterior bitewing exam at 12-24 month intervals if proximal surfaces cannot be examined visually or with a probe
Radiograph prescription for transitional dentition - new patient
Individualized radiographic exam consisting of posterior bitewings with panoramic exam or posterior bitewings and selected PAs
Radiograph prescription for transitional dentition - recall with high caries risk
Posterior bitewing exam at 6-12 month intervals if proximal surfaces cannot be examined visually or with a probe
Radiograph prescription for transitional dentition - recall with low caries risk
Posterior bitewing exam at 12-24 month intervals if proximal surfaces cannot be visualized or felt with a probe
Radiograph prescription for adolescent in permanent dentition - new patient
Individualized radiographic exam consisting of posterior bitewings with panoramic exam or posterior bitewings and selected periapical images
Full mouth intraoral radiographic exam is preferred when patient has clinical evidence of generalized oral disease or history of extensive dental treatment
Radiograph prescription for adolescent in permanent dentition - recall with high caries risk
Posterior bitewing exam every 6-12 months if proximal surfaces cannot be examined visually or with a probe
Radiograph prescription for adolescent in permanent dentition - recall with low risk
Posterior bitewing exam at 18-36 month intervals
Radiograph prescription for adult patient - new exam
Individualized radiographic exam consisting of posterior bitewings with panoramic exam or posterior bitewings and selected periapical images
Full mouth intraoral radiographic exam is preferred when patient has clinical evidence of generalized oral disease or history of extensive dental treatment
Radiograph prescription for adult patient - recall with high risk
Posterior bitewing exam at 6-18 month intervals
Radiograph prescription for adult patient - recall with low risk
Posterior bitewing exam at 24-36 month intervals
Positive clinical signs and symptoms
Clinical evidence of periodontal disease Large or deep restorations Deep carious lesions Clinically impacted teeth Swelling Evidence of trauma Mobility of teeth Sinus tract Clinical suspected sinus pathology Growth abnormalities Positive neurological symptoms in head and neck Clinical tooth erosion Unexplained bleeding
Standard (universal) precautions
Handwashing Use of gloves/mask/eye protection Patient care equipment Environmental surfaces Injury prevention
Intended to prevent spread of organisms by blood and other sources
Personnel health elements
Education and training Immunizations (strongly recommended) Exposure prevention and management Medical condition management Health record maintenance
Degrees of hand hygiene
Routine hand wash: 15 seconds with soap and water
Antiseptic hand wash: 15 seconds with antimicrobial soap
Antiseptic hand rub: until hands are dry
Surgical antisepsis: antimicrobial soap and water for 2-6 minutes (forearms) or plain soap and water followed by alcohol-based surgical scrub
Mechanical monitor of sterilization
Cycle Time
Pressure
Temperature
Biological Indicators of sterilization
Should be done at least weekly
Should be done with every load containing implantable material
Use control BI from same lot
When should you use biological indicators?
A new type of packaging material or tray is used
After training new sterilization personnel
After repair
After change in loading procedures
Chemical indicators of sterilization
Internal indicator should be placed in every package
External indicator if internal cannot be seen from outside packaging
Medical waste
Not considered infection - discard with regular trash
Regulated medical waste
Potential risk for infection during handling and disposal
Solid waste soaked with blood or saliva
Extracted teeth
Surgically removed hard or soft tissues
Contaminated sharps
Guidelines for exposure determination and prevention
Discharge air and water for 20-30s after each patient
Anti-retraction valves in water lines
Water lines
Regulatory standard for drinking water is less or equal to 500 CFU/mL
Simply using source water containing equal or less than 500 CFU/mL of bacteria in a self containing system will not eliminate bacterial contamination in treatment water if biofilms in water system are not controlled
Requires use of chemical germicides
Categories of patient care instruments
Critical: penetrates soft tissue, contacts bone, enters or contacts bloodstream (scalers, scalpel, burs)
Semi-critical: contacts mucous membranes or non-intact skin (dental mirror, dental trays)
Non-critical: contacts intact skin (radiograph head)
Sterilization definition
Destroy all microorganisms including bacterial spores
Heat automated High Temperature
Low temperature
Liquid immersion
Heat automated high temperature sterilization
Ex: steam, dry heat
Can be used for heat tolerant critical and semi-critical instruments
Low temperature sterilization
Ex: ethylene oxide gas, plasma sterilization
Can be used for heat sensitive critical and semi-critical
Takes 10-16 hours
Liquid immersion sterilization
Ex: chemical sterilant, glutaraldehyde, hydrogen peroxide
Can be used for heat sensitive semi-critical instruments
High-level disinfection definition
Destroy all microorganisms but no necessarily all spores
Heat automated (washer/disinfector) Liquid immersion
Used for semi-critical
Intermediate level disinfection definition
Destroy vegetative bacteria and majority of fungi and viruses
Liquid contact (EPA disinfectant with tuberculocidal activity, chlorine-containing products, quaternary ammonium compounds)
Can be used for non-critical items with visible blood
Low level disinfection
Destroys vegetative bacteria and majority of fungi but does not inactivate mycobacterium
Liquid contact (EPA disinfectant without label claim of antituberculosis activity, chlorine containing products, quaternary ammonium compounds
Can be used for non-critical items with no blood
How to disinfect a dental cast before sending to a lab?
Spray until wet
Use chlorine compounds
How to disinfect alginate?
Disinfect by immersion
Only disinfectants with short term exposure time (chlorine compounds or iodophors)
