Class II Preparation Flashcards
What is the definition of a class II carious lesion?
A smooth surface caries lesion found on the interproximal surface of posterior teeth.
What is the most common location of a class II caries?
Found both mesially & distally usually just below the contact points.
What does the diagnoses of a class II lesion as E2 mean?
That the lesion is an incipient caries, into the inner part of enamel but has not yet broken the DEJ, and should therefore not be restored.
What does the diagnoses of a class II lesion as D2 mean?
A D2 carious lesion is a moderate caries that has penetrated the DEJ and therefore must be restored.
Besides E2 & D2, what are the other classifications of class II caries?
E1 = small incipient D1 = mild caries D3 = Large caries
If a restoration is a ‘compound’ restoration what does that mean? How is a compound restoration named?
Compound restorations are 2 surface preparations. They take the name of both surfaces, i.e. mesio-occlusal (MO).
What is a 3+ restoration called?
Complex
What shape does a class II carious lesion take as it crosses the DEJ and progresses to an E2 stage?
Apex-to-base shape. Class II caries start out as broad decalcifications and come to a point at the DEJ. They then spread out across the DEJ and proceed toward the pulp forming a second apex.
How are class II caries detected?
Class II’s are very difficult to detect w/o the use of an X-ray. May eventually see an opacity over the marginal ridge, however, this is only visible after the caries has progressed and undermined the enamel.
The occlusal surface is usually included in a class II prep to improve retention (“extension for prevention”). What are 3 exceptions to this rule?
- Maxillary molars & their Oblique Ridges
- Mandibular 1st premolar & its Transverse Ridge
- Conservative slot preps w/ Composite
What are point angles and what are the two point angles in a class II prep called?
Point angles are the intersection of THREE walls. In a class II prep there is a Buccoaxiogingival and a linguoaxiogingival point angle.
What is the 1st place you should pack amalgam in a class II restoration? Why?
In the point angles b/c they are the points of greatest retention.
On a mesial class II prep, should the mesiolingual & mesiobuccal walls be convergent or divergent?
convergent
Why is it important to slightly round the axiopulpal line angle?
B/c amalgam hates sharp edges?
What is a butt-joint and what should its angle be?
A butt-joint is the cavosurface angle formed at the buccogingival & linguogingival walls. These walls should be parallel w/ the enamel rods thus creating a 90 degree angle @ the external wall.
