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Primary flares also have a special angulation i.e. 45째 to the inner dentinal wall proper.
They bring the facial and lingual margins of the cavity preparation to cleansable finishable areas. They are indicated for any facial or lingual proximal wall of an intracoronal cavity preparation.
Secondary flare: -
It is almost always a flat plane super imposed peripherally to a primary flare.
-
It is usually prepared solely in enamel.
-
Unlike primary flares, secondary flares may have different angulations, involvement and extent depending on their function.
Indicated in very widely extended lesions bucco-lingually and in very broad contact areas or malposed area.
4. Mechanical problems for cast restorations and preparation design solutions in general. The numerous auxiliary means of retention for cast restorations are: a. Luting cements -
Action is primarily mechanical, locking the casting
to tooth
structure by filling the space between them, wetting the details of both the casting and tooth preparation and filling in the vacancies or irregularities.
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