Begin your preparation by first selecting the crown size that best fits the tooth. This is done by holding a crown up to their existing tooth. Alternatively, if you have a digital x-ray system, you may pre-size the crown by taking measurements in your software and match your patients interproximal width to the corresponding crown size. Your Kinder Krowns® kit box has a sizing chart located on the internal aspect of the lid.
Preparation is very similar to that of Pre-veneered Kinder Krowns®. For your incisal reduction, we recommend using a coarse grit wheel diamond bur (1.2mm). However, bur selection depends completely on your preference. Reduce the incisal surface of the tooth approximately 1 - 1.5mm.
Reduce buccal-lingually approximately 1-1.5 mm using a flame-shaped diamond bur. During buccal-lingual reduction, keep the bur parallel to the tooth. Keeping the bur parallel to the tooth ensures consistent reduction from the occlusal down to the gingival tissue.
Next reduce interproximally 1mm using a flame-shaped diamond bur, such as a .368 or a .330 tapered carbide. During interproximal reduction, keep the bur parallel to the tooth and remain supragingival. This technique will reduce the likelihood of contacting the pulp.
Using a flame-shaped diamond bur reduce subgingivally 1-2mm, ending with a feathered margin. Often there is a remaining band of tooth structure, just below the tissue - removing that tooth structure is the key to achieving a passive fit.
The most important key to remember when placing Zirconia Kinder Krowns® is that a passive fit is required. Zirconia Kinder Krowns® are solid ceramic and do not flex. If the crown won’t go into place without resistance, you will need to reduce more tooth structure. The appropriately sized crown will seat passively and subgingivally 1-2 mm and should not alter the gingival tissue.
After the preparation is complete and all of the crowns fit passively, the crowns can be filled with your cement of choice. Many dentists are using a straight-glass ionomer, however a resin-modified glass ionomer is certainly adequate.