principles of cavity preparation Flashcards
In what year did gv black define cavity classification ?
1896
Who is responsible for the classification of cavities
Green vardiman black
What is a class l cavity?
Occlusal surfaces of pre molars and molars
Buccal pits of molars
What is a class ll cavity?
Approximal surfaces of molars and pre molars
What is a class lll cavity?
Approximal surfaces of incisors and canines
What is class lv cavity?
Inscisal edges of incisors and canines
What is a class v cavity?
Cervical margins
What are the disadvantages of blacks classifications
Pre adhesive materials- re retention
Removes more tooth substance than neccessary
Does not indicate root surface caries and secondary caries
What are the 6 principles of blacks cavity prep?
Outline form Resistance form Retention form Tx of residual caries Correction of enamel margins Cavity debridement
What is meant by outline form ?
Gaining access to caries
Dependant on location of caries
Traditionally by cutting through over lying enamel
What is resistance form ?
To resist occlusal forces
To enable restoration and remaining tooth to withstand mastication forces
Cavity floor at right angle to occlusal forces
Sufficient depth (2mm) amalgam
What is retention form ?
To retain material in the cavity
Grooves in cavity wall Undercut cavity Occlusal keys Bonded amalgam Dentine pins- no longer indicated
Treatment of residual caries
Remove caries from ADJ first
Soft dentine should be removed
Firm but stained dentine can be left
Preserve oblique ridge where possible in max molars
How should caries be removed?
Using a slow rotating bur
Finished with hand excavator
What is the line angle?
Where two surfaces meet
