Radiation/Infection Control

Question 1

Image Gently

Answer 1

The Alliance for Radiation Safety in Pediatric Imaging

National alliance with goal of decreasing radiation/being more aware of radiation in pediatrics

Question 2

Millimeter-Wave Technology Unit

Answer 2

Airport security scanner

Uses non-ionizing radio-frequencies in millimeter wave spectrum to generate an image based on energy reflected from the body

Question 3

Pregnancy and radiation

Answer 3

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)

Question 4

How are x-rays formed?

Answer 4

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

Question 5

Electromagnetic spectrum

Answer 5

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

Question 6

3 interactions of x-ray with matter

Answer 6

Coherent Scattering

Photoelectric absorption

Compton Effect

Question 7

Compton effect

Answer 7

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

Question 8

What percentage of the scattered photons formed during a dental x-ray exposure exit the patient’s head?

Answer 8

30%

Scattered photons travel in all directions

9% pass through without any interaction

Question 9

Most radiosensitive cells

Answer 9

Those with high mitotic rate

Those that will undergo future mitosis

Cells with primitive differentiation

Question 10

Deterministic effects

Answer 10

Response is proportional to the magnitude of the dose

Question 11

Stochastic effect

Answer 11

The response is proportional with the frequency of the dose

Most related to dental radiography

Question 12

Earth Radiation

Answer 12

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)

Question 13

How much radiation is in a bitewing?

Answer 13

3.6mSv / 365 = 0.00986 mSv per day

One posterior bitewing is 0.005 mSv (with rectangular collimation) -> about 0.6 background radiation days

Question 14

What is the best way to reduce radiation exposure?

Answer 14

Rectangular collimation

Reduces by 50%

Question 15

Digital imaging versus film

Answer 15

Reduces dose of radiation compared to film

However, ease of retakes and increase in number makes this effect not as large

Question 16

Dose reduction of digital versus F-speed film

Answer 16

0-50%

Question 17

Handheld x-ray system

Answer 17

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

Question 18

Justification for radiographs (overview)

Answer 18

Patient selection

Positive clinical signs/symptoms

Question 19

Patient selection for radiographs

Answer 19

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

Question 20

When should a dentist prescribe dental radiographs?

Answer 20

Only AFTER clinical evaluation

Question 21

Radiograph prescription for a child with primary dentition - new patient

Answer 21

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

Question 22

Radiograph prescription for a child with primary dentition - recall with high caries risk

Answer 22

Posterior bitewing exam at 6-12 months if proximal surfaces cannot be examined visually or with a probe

Question 23

Radiograph prescription for a child with primary dentition - recall with low caries risk

Answer 23

Posterior bitewing exam at 12-24 month intervals if proximal surfaces cannot be examined visually or with a probe

Question 24

Radiograph prescription for transitional dentition - new patient

Answer 24

Individualized radiographic exam consisting of posterior bitewings with panoramic exam or posterior bitewings and selected PAs

Question 25

Radiograph prescription for transitional dentition - recall with high caries risk

Answer 25

Posterior bitewing exam at 6-12 month intervals if proximal surfaces cannot be examined visually or with a probe

Question 26

Radiograph prescription for transitional dentition - recall with low caries risk

Answer 26

Posterior bitewing exam at 12-24 month intervals if proximal surfaces cannot be visualized or felt with a probe

Question 27

Radiograph prescription for adolescent in permanent dentition - new patient

Answer 27

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

Question 28

Radiograph prescription for adolescent in permanent dentition - recall with high caries risk

Answer 28

Posterior bitewing exam every 6-12 months if proximal surfaces cannot be examined visually or with a probe

Question 29

Radiograph prescription for adolescent in permanent dentition - recall with low risk

Answer 29

Posterior bitewing exam at 18-36 month intervals

Question 30

Radiograph prescription for adult patient - new exam

Answer 30

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

Question 31

Radiograph prescription for adult patient - recall with high risk

Answer 31

Posterior bitewing exam at 6-18 month intervals

Question 32

Radiograph prescription for adult patient - recall with low risk

Answer 32

Posterior bitewing exam at 24-36 month intervals

Question 33

Positive clinical signs and symptoms

Answer 33

``` 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 ```

Question 34

Standard (universal) precautions

Answer 34

``` 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

Question 35

Personnel health elements

Answer 35

``` Education and training Immunizations (strongly recommended) Exposure prevention and management Medical condition management Health record maintenance ```

Question 36

Degrees of hand hygiene

Answer 36

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

Question 37

Mechanical monitor of sterilization

Answer 37

Cycle Time Pressure Temperature

Question 38

Biological Indicators of sterilization

Answer 38

Should be done at least weekly Should be done with every load containing implantable material Use control BI from same lot

Question 39

When should you use biological indicators?

Answer 39

A new type of packaging material or tray is used After training new sterilization personnel After repair After change in loading procedures

Question 40

Chemical indicators of sterilization

Answer 40

Internal indicator should be placed in every package External indicator if internal cannot be seen from outside packaging

Question 41

Medical waste

Answer 41

Not considered infection - discard with regular trash

Question 42

Regulated medical waste

Answer 42

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

Question 43

Guidelines for exposure determination and prevention

Answer 43

Discharge air and water for 20-30s after each patient Anti-retraction valves in water lines

Question 44

Water lines

Answer 44

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

Question 45

Categories of patient care instruments

Answer 45

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)

Question 46

Sterilization definition

Answer 46

Destroy all microorganisms including bacterial spores Heat automated High Temperature Low temperature Liquid immersion

Question 47

Heat automated high temperature sterilization

Answer 47

Ex: steam, dry heat Can be used for heat tolerant critical and semi-critical instruments

Question 48

Low temperature sterilization

Answer 48

Ex: ethylene oxide gas, plasma sterilization Can be used for heat sensitive critical and semi-critical Takes 10-16 hours

Question 49

Liquid immersion sterilization

Answer 49

Ex: chemical sterilant, glutaraldehyde, hydrogen peroxide Can be used for heat sensitive semi-critical instruments

Question 50

High-level disinfection definition

Answer 50

Destroy all microorganisms but no necessarily all spores ``` Heat automated (washer/disinfector) Liquid immersion ``` Used for semi-critical

Question 51

Intermediate level disinfection definition

Answer 51

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

Question 52

Low level disinfection

Answer 52

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

Question 53

How to disinfect a dental cast before sending to a lab?

Answer 53

Spray until wet Use chlorine compounds

Question 54

How to disinfect alginate?

Answer 54

Disinfect by immersion | Only disinfectants with short term exposure time (chlorine compounds or iodophors)