Biocompatibility Flashcards
Define biomaterial
Substance/combination of synthetic or natural in origin - can be used for any period of time that treats, augments, replaced any tissues, organ or function of the body
Define biocompatibility - does absolute biocompatibility exist?
Ability of a material to elicit appropriate response in a given application
No absolute biocompatibility
What are the 3 criteria for biocompatibility?
Host (patient)
Material
Function of the material
Name 3 factors that could cause biocompatibility to change
Corrosion/fatigue, occlusion/diet, disease/aging
What is a foreign body reaction
Material reacts with surrounding biological systems
Name some reactions common intra-orally, on hands, the face and lips
Ulceration/blisters/vesicles
Swelling/tenderness/reddening
Name some reactions that affect the general body
Breathing problems/wheezing/asthma
Running/irritated eyes/nose
Coughing/sneezing/sore throat
Headaches/nausea/dizziness
What is the LOAEL and who authorises it?
Lowest observed adverse effect level
- 50ug/m3
- WHO
What is the NOAEL?
No observed adverse effect level
- 25 ug/m3 - factory
- 5 ug/m3 - general public
- 1 ug/m3 - children, sick, pregnant
Name 3 considerations for dental materials
Exposure potential
Human factors
Exposure factors
What are the LOAEL and NOAEL assessments used for?
Assigning the Hg in the air
List 5 exposure factors
Accumulation in tissues Excretion characteristics Length Route Quantity
What is an essential trace element?
Elements that are necessary for physiological functions but toxic in higher than normal concentrations
List the essential trace elements
Zinc Iodine Selenium Iron Cobalt Copper Chromium Molybdenum
Define corrosion
Dissolution/formation of compounds
What disease does absorbing MeHg cause?
Minamata disease
Define a toxic material
A material that releases chemicals in sufficient quantities to kill cells either directly/indirectly through inhibition of key metabolic pathways
What does dose dependent mean?
The toxicity of the material depends on the dose
- one large time dose above the threshold
- repeated small doses
List 5 allergens found in dental materials
Eugenol Mercury Nickel Chromium Components of resin based materials
What is most likely to cause reactions in patients?
Metal
What is most likely to cause reactions in dental surgery staff?
Latex gloves
What is most likely to cause reactions in dental technicians?
Acrylic resin
According to the 1972 ANS/ADA 41 - what are dental materials classed as and what does that mean?
Classed as devices and not drugs
This means they only have to show safety, not efficacy
What is an in vitro test?
Uses cell outside of an organism
What is a usage test?
Intact organism exposed to material without regards to final use
Biological response measured
What is a clinical trial?
Material placed in clinically relevant environment to use of material in clinical practice in humans
Golden standard
List the advantages and disadvantages of in vitro test
- advantages Controllable Isolatable Repeatable Fast Relatively inexpensive and simple
-disadvantages
May provide misleading results
List the advantages and disadvantages of usage tests
- Advantages
most relevant
- Disadvantages expensive time consuming very difficult to control difficult to interpret
