Biocompatability Flashcards
What is the definition of a biomaterial?
Biological materials either synthetic or natural that are used as part of an implanted medical device to replace an organ or bodily function.
What can biomaterials be used for?
- Medical implants
- Repairing/healing human tissue
- Cellular scaffolds for regenerating tissues
- Molecular probes and nanoparticles
- Biosensors
- Drug-delievery systems
What are the 4 categories of concern when we are considering biocompatability?
- Safety to patient
- Safety to staff
- Regulatory compliance
- Legal liability
What is biocompatability?
The ability of a material to perform with an appropriate host response in a given specific application.
What are the key elements that we want a material to have?
- Non toxic
- Non irritant
- Minimal inflammation
- Tissue integration
- Physical and mechanical properties
- Not carcinogenic
What two way biological interaction occurs between the implant and the body?
- Effect implant has on body
- Effect body has on inplant
What are the 3 effects that the body has on the implant?
- Protein absorption (proteins in the body cover the implant allowing cells to adhere)
- Degradation (enzymes from body have an affect on the material and breakdown the implant)
- Corrosion = need to consider that some metals used in the body are corrosive
What affect does the implant have on the body?
1 - Blood-clot equilibrium disturbed 2 - Inflammatory response 3 - Chronic inflamamtion 4 - Evokes immune response 5 - wound healing resumed and endothelial cells and fibroblasts regenerate tissues
What screening tests do we do to check the biocompatibility of a material?
Cytotoxicity tests are done that assess cell numbers, metabolic activity and any other reaction.
In vitro tests are rapid and inexpensive.
Once done, move onto in vivo tests in animals before clinical trials.
What factors influence the biocompatability?
- The material
- The duration of exposure
- Location of the material (load bearing site)
- Health of host
What 3 tests are in the pyramid of test progression?
In vitro tests (non specific toxicity)
In vivo tests (specific toxicity - using specific cells
Clinical trials
What company regulates biocompatabiltiy?
ISO (international organisation for standardisation)
What are the two aspects of biocompatibility that we must assess?
- Biosafety
- Any damaging effects on the host - Biofunctionality
- Does the material elicit a beneficial host-response for optimal functioning?
What are the 2 classifications for in vitro tests?
DIRECT = testing the material with the cells it will come into contact with directly
INDIRECT = a barrier between the material and cells are made to see if they are any leachable toxins which affect the cells.
What are the two types of cells we can use in in vitro testing?
Primary cells = cell extracted from a tissue directly
Cell lines = primary cells transfected with a virus which affects the cell at a point in the cell cycle.
When we do in vitro testing, there are 3 things we need to make sure that the test has, what are they?
1 - Specificity - appropriate cells being used
2 - Sensitivity - method used needs to be sensitive enough to pick up toxicity
3 - Quality controls - need to have a control in the test to give a negative outcome (non toxic)
What is a common bodily reaction to placing a dental material?
- Inflammation
- Allergic reaction
What are the two interfaces that a dental material can be with?
Soft tissue of mouth
Hard tissue of mouth
WHO is most at risk when using a toxic dental material?
The dentist.
Why is amalgam a potential problem?
Mercury vapour is released during manipulation, placement or removal of amalgam.
Are resin composites biocompatable?
Components releases from resin can affect a small change in local environment.
Incomplete polymerisation can be an issue as leads to degradation of the material, leaching, and imperfect bonding.
Can get a pulp reactions and develop recurrent caries.
Do GICs have a good biocompatability?
Minor irritation to the pulp.
GOOD BIOCOMPATIBILITY.
What can gold do to the oral cavity?
Might be a pulp reaction due to condensation.
Rare allergic reactions to alloy metals.
Can a material still cause an effect in the body and be biocompatiable?
Only if they are short lived.
