Philips’s science of dental materials
Hoofdstuk 2
Combination of primary bonds bestaat ook.
- Calciumsulfaat
Hydrogen bond
- Covalent
, Hoofdstuk 3
Thermal conductivity (geleidbaarheid) = k
- Hoog: conducturs
- Laag: insulators
Thermal conductivities:
Polymers < ceramics < metals
Thermal diffusity: h
measure of the speed with which a temperature change will spread through an object when
one surface is heated.
- Material with high density and high specific heat will have a low thermal diffusity
For tandheelkunde
thermal diffusity more imporant than thermal conductivity
Thermal expansion = a (alfa)
When material undergo a temperature increase, the virbrational motion of atoms and mean
interatomic (bond) distances increase
increase in volume (expansion)
delta L
=a
L x deltaT
L= the original lengts
Delta L= change in length
Delta T= temperature change
Electrical properties
Corrosion: electrochemical process and is dependent on the ability to conduct electrical
current
- Free electrons in metals
- Via ions in solution
Most important electrochemical effects
- Toxic
- Allergic responses
In most cases: corrsosion is undesirable
The oral environment is highly conducive to electrochemical action
Tarnish: aanslag(mat)
Tarnish often occurs from the formation of deposits on the surface of a restauration
- Bijv of the formation of thin films (oxides, sulfides, chlorides)
Hoofdstuk 2
Combination of primary bonds bestaat ook.
- Calciumsulfaat
Hydrogen bond
- Covalent
, Hoofdstuk 3
Thermal conductivity (geleidbaarheid) = k
- Hoog: conducturs
- Laag: insulators
Thermal conductivities:
Polymers < ceramics < metals
Thermal diffusity: h
measure of the speed with which a temperature change will spread through an object when
one surface is heated.
- Material with high density and high specific heat will have a low thermal diffusity
For tandheelkunde
thermal diffusity more imporant than thermal conductivity
Thermal expansion = a (alfa)
When material undergo a temperature increase, the virbrational motion of atoms and mean
interatomic (bond) distances increase
increase in volume (expansion)
delta L
=a
L x deltaT
L= the original lengts
Delta L= change in length
Delta T= temperature change
Electrical properties
Corrosion: electrochemical process and is dependent on the ability to conduct electrical
current
- Free electrons in metals
- Via ions in solution
Most important electrochemical effects
- Toxic
- Allergic responses
In most cases: corrsosion is undesirable
The oral environment is highly conducive to electrochemical action
Tarnish: aanslag(mat)
Tarnish often occurs from the formation of deposits on the surface of a restauration
- Bijv of the formation of thin films (oxides, sulfides, chlorides)
