Anterior Crowns Offer Strength and Aesthetics

Dentistry Today


The Znext Anterior Full Contour Zirconia from Keller Laboratories gives dentists another option for anterior restorations. According to the company, it provides more strength than a traditional lithium disilicate crown and more aesthetics than a posterior all-ceramic crown.

These full-contoured zirconia crowns and bridges have no porcelain overlay. Instead, they are glazed with a smooth surface but designed for the anterior with emphasis on translucency and natural color.

Specimens of the zirconia products were more translucent at 0.5-mm thickness than at 1.0-mm thickness, according to Keller Laboratories. At the 0.5-mm thickness, the translucency parameter ranged from 10.3 to 10.7, and the company claims that Znext was significantly more translucent than other products.

Znext’s 650-MPa flexural strength also is greater than that of pressed ceramics like lithium disilicate to provide completely chip-proof restorations, tested per ISO 6872 specifications, the company says. It is made with biocompatible medical-grade zirconia and fabricated using CAD/CAM technology for a consistent fit.

Keller recommends reinforced glass ionomer cement. For short or over-tapered preparations, dentists should use resin cements. Shoulder preparation is not needed, and a feather edge would be acceptable. Conservative preparation is similar to full cast gold. And while 1.0 mm of occlusal space is ideal, a prep with at least 0.55 mm is acceptable.

Saliva contamination can hinder the bonding of solid zirconia and zirconia oxide copings, according to the company. To successfully remove saliva, Keller suggests cleaning the crown with Ivoclar Vivadent’s Ivoclean zirconia oxide solution after try-in and before priming.

Keller can accept digital scans for Znext, though dentists can use traditional models or impressions as well. Compatible scanning systems include the CEREC (Sirona Dental), True Definition (3M), TRIOS (3Shape), and CS 3500 (CareStream). Single-unit crowns up to 3-unit bridges to the second premolar also are available without a model to save time and money.

For more information, call (800) 325-3056 or visit

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