Cavity Preps Flashcards
In what cases do we need to end with diverging walls in class I?
When needing to remove enamel undercuts (unsupported enamel)
Where should the pulpal floor be?
Always on Dentin, ideally just below the DEJ
Pulpal floor is flat or follows the rise and fall of occlusal surface
What is the ideal orientation of enamel rods in a prep?
full length of rods, supported by shorter rods both attached to sound dentin
In what cases should we reduce the cusp tips?
when caries covers 1/2 distance from primary groove to cusp tip
when caries covers 2/3 from an adjacent primary groove to the cusp tip
What is a dovetail?
= a primary retention feature (extension for retention)
What is the guideline for formation of the proximal box in class II?
extend gingivally past either caries or occlussal contact (whichever is deeper)
2/3 expense of enamel, 1/3 expense dentin
What form does the axial wall of the proximal box has?
faciolingual contour of proximal tooth surface
In which cases are cusp reductions usually required in class II?
DB cusp of maxillary M2
D cusp of mandibular M1
When is Adjoining restorations permissible?
when the remaining has adequate resistance and retention forms
What do we need to consider for class II on mandibular P1?
- location of pulp chamber
- size of lingual cusp
- entry of bur should be tilted at bisector of angle between long axis of tooth and line perpendicular to faciolingual cusp tips
Where are retention grooves placed in the class II proximal box?
axiolingual and axiofacial line angles always in bisector
Where are retention grooves placed in the lingual prep of 2 surface class I?
distoxaial and mesioaxial line angles
The depth of retention grooves is usually the size of half the diameter of the bur used (0.25 - 0.5 mm deep)
What secondary retention features do we place for class V?
Retention grooves: occlusoaxial and gingivoaxial
Retention coves:
in each axial point angle
If the facial wall is divergent what secondary retention feature is added?
A retention undercut in the faciopulpal line angle
Which area do carries grow faster in?
Pit and fissure