Lecture 8

Question 1

Adv and disadv of biopolymers/?

Answer 1

Easy to fabricate into forms: films, fabrics, solids
Do not corrode
Only metals can corrode
Close resemblance to tissue (density)
Tissue is 1.1 g/cc 
Good adhesive properties

Poor mechanical properties
Cannot make a bone screw as it cannot take the load
Usually can not be completely polymerized, thus subject to biodegradation and leaching (toxic)
bioincompatibility
Most polymers have additives built in them
Add a filler to make it stronger (glass?)

Question 2

Common characteristics

Answer 2

Abckbone of C or Si, bonds not co linear, canchave more than a single bond, properties dependent on length—e.g. melting point increases eith longer culex

Question 3

structural components of composites

Answer 3

matrix–blend or aromatic or aliphatic dimethacrylate monomers)

filler–glass particles, for reinforcement, reducing shrinkage, dimensional stability

coupling agent–organosilanes to promote adhesion bw matrix and fillers

activator initiator system–free radicals to respond to light

pigments

inhibitors–min blue light to polymerize

optical modifiers–for shading and translucence

Question 4

what ar ethe light activation lamps>

Answer 4

LED lamps: blue part of the spectrum (440 nm- 480 nm)

QTH lamps : 400-500 blue violet

PAC lamps: 400-500 nm

argon laser lamp–single wavelength of 490 nm

Question 5

give examples of biopolymers

Answer 5

UHMWPE–>for TMJ prosthetic; wore away less quickly

PMMA

nylon
polyporpylene
silicone

Question 6

know slide 18

Answer 6

ye