Lecture 15

Question 1

define biocompatilibity?

Answer 1

the ability of a material to do its job without eliciting any adverse affects from the pt

Question 2

what are the ways to evaluate biocomp.?

Answer 2

• compositional analysis
• surface degradation tests
• cell culture tests
• ex vivo (blood)
• animal models test
• clinical testing in humans

Question 3

what are the factors biocompatibility depends on?

Answer 3

• chem nature of components
• physical nature of the components
• types and location of pt tissue exposed to a biomaterial
• duration of exposure
• surface characteristics
• amount and nature of eluted substances

Question 4

define adverse rxn?

Answer 4

any unintended, unexpected, harmful response of the pt to a biomaterial

Question 5

what is critical adverse effect?

Answer 5

first event that is observed at the lowest exposure level

Question 6

what is critical tissue/organ

Answer 6

location of the adverse effect

Question 7

what is critical concentration?

Answer 7

conc that produces the adverse effect

Question 8

what are the regulatory classes of materials?

Answer 8

class I: low risk (eg. ortho wires)-- do not need 510 (K) submission
class II: moderate risk (e.g. bone screws) (need 510 K submission)
class III: high risk e.g. drugs

Question 9

what are potential adverse effects of dental amalgam?

Answer 9

• contact dermatitis or sensitization to metal elements
• lichenoid lesion
• adverse pulpal rxn or sensitivity
• thermal sensitivity (ag transfer heat)
• acute/systemic Hg toxicity

Question 10

potential adverse effects of resin-based composed?

Answer 10

• contacts dermatitis sensatization to methacrylates
• lichenoid lesion
• estrogenic effects of bis phenol A
• cytotoxicty systemic effect
• systemic effects of free monomer or leaches substance

Question 11

potential adverse effects of cast metal and condensed foil

Answer 11

• contacts dermatitis sensatization to metals (e.g. Ni, Cu, Be)
• lichenoid lesion
• thermal sensitivity of pulp
• systemic effects of leached metal ions

Question 12

potential adverse effects of ceramic

Answer 12

• resp effects from silica dust, excessive wear of opposite teeth
• susc. to chipping

Question 13

define estrogenicity

Answer 13

potential of a chem to act in the body in a manner similar to that of estrogen

Question 14

define lethal dose fifty

Answer 14

calc. dose of a substane expected to kill 50% of the experimental animal population

Question 15

what is LOAEL?

Answer 15

lowest observed adverse effect level –> lowest tested dose of a substance that has been reported to cause harmful effects in animals or humans

Question 16

what is NOAEL?

Answer 16

no observed adverse effect level

-highest tested dose of a substance that has been reported to have no harmful effects in people or animals

Question 17

requirement for biocompatibility testing

Answer 17

1. the test should be performed under condition that stimulate the actual use of the material in the body
2. the test condition should reflect the effects of the material time in the body on the biological response
3. stresses induced in the material under its intended function should be considered in the interpretation of the biological response

Question 18

specificis of biocompatibility testing conditions

Answer 18

1. contact of the material with soft or mineralized tissue
2. will the material be positioned external to the oral epithelium
3. will the material serve as an endosseous implants
4. exposure of the material directly to bone, tissue, fluid, blood, and saliva
5. will there be a barrier such as dentin to separate the material from living cells

Question 19

what is biointegration?

Answer 19

The process of forming an interface between bone or other living tissue and an implanted material with no intervening space.

Question 20

define chronic exposure

Answer 20

The contact with a substance that occurs over a long time (more than 1 year)

Question 21

describe osseointegration

Answer 21

The process of forming a direct structural and functional interface between live bone and an artificial implant surface without any intervening fibrous connective tissue

Question 22

what is reference dose?

Answer 22

An Environmental Protection Agency (EPA) estimate, with uncertainty or safety factors built in, of the daily lifetime dose of a substance that is unlikely to cause harm in humans

Question 23

define safety

Answer 23

The absence (freedom) from unacceptable risks.

Question 24

describe sensitization

Answer 24

The process by which an allergy antibody is produced, which reacts specifically to the causative foreign substance.

Question 25

whata re the main factors that determine the success of dental mateirals?

Answer 25

(1) material properties, (2) the design of the dental device, and (3) the biocompatibility of component materials.

Question 26

what are the types of adverse rxns?

Answer 26

allergic reaction, chemical burn, pulp irritation, pulp damage, thermal injury, tissue irritation, and toxic reaction

Question 27

ere are no direct tests for the diagnosis of toxicity reactions. Speci c tests such as urinary mercury con- centration can help clinicians complement their di erential diagnoses. Toxicity diagnoses are also based on the signs and symptoms presented by the patient and by a review of the history of possible exposures to a suspected toxin

Answer 27

ye