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It is relatively atraumatic to the health of the tooth because it involves removing very little (if any) dentin. Usually the skirt extensions are prepared entirely in enamel.
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The preparation of a skirt is done entirely with the slender, flame-shaped, fine-grit diamond instrument. Skirt preparations follow the completion of the proximal gingival bevel and primary flares. However, experienced operators will often prepare the skirt extensions at the same time that the gingival bevel is placed, working from the lingual toward the facial or vice versa.
Indications •
Skirting is to involve defects with more dimensions than those that can be involved in a reverse secondary flare.
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It is required to impart resistance and retention on a cast restoration.
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It is necessary when contact areas and contour of proximal surfaces are to be changed in the contemplated restorations.
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Skirts are essential facially and lingually for tilted teeth in order to restore the occlusal plane and are prepared at the side torwards, which the tooth is tilted.
Features: •
Skirts include facial and lingual surfaces at axial angles to a depth 0.5-1 mm in class –I and II alloys, and a depth of 1.5 – 2 mm for class III, IV and V cast materials.
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The maximum depth of skirts should be at the junction of the surface extension with the cavity preparation.
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For class – I, II and III skirt ends at mesially (or) distally in a chamfer line. For class IV and V the skirt ends in a hollow ground bevel.
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It is sometimes preferable to terminate the skirt mesially or distally in a vertical groove, and is used to accommodate bulky material.
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The depths should be 1-2mm for classes I and II and 2mm for cast ceramics. 57