C - FACTOR IN COMPOSITE
CONFIGURATION FACTOR ( C- FACTOR)
- It is a three dimensional configuration of a prepared cavity.
- c - factor was introduced by feilzer in the year 1987
- Configuration factor is calculated by the number of bonded surface to unbounded surface .
- composite resin undergo polymerisation shrinkage : polymerisation shrinkage is a process that occurs when resin gets cured.
- stress generation along bonded area as they are bonded micro mechanically
- free surface - free flow of composite thereby decreasing stress.
NOTE: REFER THE ABOVE IMAGE - In order to get a better understanding on bounded and unbounded surface in a prepared. cavity
REASONS FOR POLYMERISATION SHRINKAGE
- When composite resin gets cured ,during
- the polymerisation process since monomeric particles are more voluminous than polymer ,moneric chains gets unbounded vanderwal force of interaction gets converted to covalent bond.
- matrix generally shrink from cavity wall,material cure towards the centre of bulk pulls material away from interface.
STEPS TO AVOID POLYMERISATION SHRINKAGE:
- Incremental addition of resin
- resin layer should not exceed 2 mm in depth
- oblique layering techniques
- flowable composite liner
- increasing the filler particle content thereby decreasing polymerisation
- different technique of light curing
DETERMINATION OF AMOUNT OF STRESS DISTRIBUTION:
- In class 1 cavity preparation the number of bonded surface is five ,unbounded surface is 1 ( occlusal) in this case the c - factor is 5 that indicates more stress generation
- In class four cavity preparation- the number of bonded surface is one ,unbounded surface is 4 so the c- factor is 0.25
- In class five cavity preparation the number of bounded surface is 5 and number of unbounded is 1 so the configuration factor is 5/1
- IN ABRASIVE LESION : C - FACTOR = 1
- If configuration factor is more than 1 that means it has more potential bond distribution
- wider the cavity prepared less stress.
- Configuration factor is a very important factor to be known while handling dental composite .
- Important keywords to mention are bounded surface and unbounded surface.
- C- FACTOR FOR CLASS 1- 5;CLASS 4 -0.25,CLASS 5-5
- We need to know the steps on how to handle the situation better in a clinical scenario in order to provide the best treatment.