Often a dentist-orthopedist has to treat an almost completely ruined crown part of the tooth. In these cases we use intracanal pins to provide support for a future crown.
When there are at least 2-3 mm of supragingival tissue left we choose fiberglass pins fixed with a special composite cement. The color of the supragingival part of such a pin fits all the ceramic and zirconia crowns.
When there are places where the tooth is ruined to the gum level or even lower, we use metal golden or cobalt-chromium alloy pins.
750 gold is a perfect material for pins. Coming through the ceramic or zirconia crown light reflects from the golden pin and results in a warm and natural tone of the prosthesis. Besides, gold is softer than cobalt-chromium alloy, so with time it rolls to the root canal walls.
Cobalt-chromium alloy is used with cermet or zirconia crowns where aesthetics is not so important — usually in posterior teeth. Cobalt-chromium intracanal pins are rather cheap, and the technology of their making allows the pin to fit the canal walls accurately.
Zirconium is one of the firmest materials used in dentistry. It's impossible to pour this metal oxide from the form or to stamp it. The only way is to cut it out of a solid metal using a milling machine. In the past zirconia crowns had some disadvantages compared to the ceramical: they were too bright and not transparent. Today these problems have been solved and we can use zirconia crowns at the most aesthetically important areas, even in the front teeth. These crowns boast a great fit accuracy up to 15 microns, that is 0,015 mm.
