Biocompatability

Question 1

What is the definition of a biomaterial?

Answer 1

Biological materials either synthetic or natural that are used as part of an implanted medical device to replace an organ or bodily function.

Question 2

What can biomaterials be used for?

Answer 2

1. Medical implants
2. Repairing/healing human tissue
3. Cellular scaffolds for regenerating tissues
4. Molecular probes and nanoparticles
5. Biosensors
6. Drug-delievery systems

Question 3

What are the 4 categories of concern when we are considering biocompatability?

Answer 3

1. Safety to patient
2. Safety to staff
3. Regulatory compliance
4. Legal liability

Question 4

What is biocompatability?

Answer 4

The ability of a material to perform with an appropriate host response in a given specific application.

Question 5

What are the key elements that we want a material to have?

Answer 5

• Non toxic
• Non irritant
• Minimal inflammation
• Tissue integration
• Physical and mechanical properties
• Not carcinogenic

Question 6

What two way biological interaction occurs between the implant and the body?

Answer 6

• Effect implant has on body

- Effect body has on inplant

Question 7

What are the 3 effects that the body has on the implant?

Answer 7

1. Protein absorption (proteins in the body cover the implant allowing cells to adhere)
2. Degradation (enzymes from body have an affect on the material and breakdown the implant)
3. Corrosion = need to consider that some metals used in the body are corrosive

Question 8

What affect does the implant have on the body?

Answer 8

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

Question 9

What screening tests do we do to check the biocompatibility of a material?

Answer 9

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.

Question 10

What factors influence the biocompatability?

Answer 10

1. The material
2. The duration of exposure
3. Location of the material (load bearing site)
4. Health of host

Question 11

What 3 tests are in the pyramid of test progression?

Answer 11

In vitro tests (non specific toxicity)

In vivo tests (specific toxicity - using specific cells

Clinical trials

Question 12

What company regulates biocompatabiltiy?

Answer 12

ISO (international organisation for standardisation)

Question 13

What are the two aspects of biocompatibility that we must assess?

Answer 13

1. Biosafety
   - Any damaging effects on the host
2. Biofunctionality
   - Does the material elicit a beneficial host-response for optimal functioning?

Question 14

What are the 2 classifications for in vitro tests?

Answer 14

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.

Question 15

What are the two types of cells we can use in in vitro testing?

Answer 15

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.

Question 16

When we do in vitro testing, there are 3 things we need to make sure that the test has, what are they?

Answer 16

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)

Question 17

What is a common bodily reaction to placing a dental material?

Answer 17

• Inflammation

- Allergic reaction

Question 18

What are the two interfaces that a dental material can be with?

Answer 18

Soft tissue of mouth

Hard tissue of mouth

Question 19

WHO is most at risk when using a toxic dental material?

Answer 19

The dentist.

Question 20

Why is amalgam a potential problem?

Answer 20

Mercury vapour is released during manipulation, placement or removal of amalgam.

Question 21

Are resin composites biocompatable?

Answer 21

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.

Question 22

Do GICs have a good biocompatability?

Answer 22

Minor irritation to the pulp.

GOOD BIOCOMPATIBILITY.

Question 23

What can gold do to the oral cavity?

Answer 23

Might be a pulp reaction due to condensation.

Rare allergic reactions to alloy metals.

Question 24

Can a material still cause an effect in the body and be biocompatiable?

Answer 24

Only if they are short lived.