4 Years Clinical Behavior of CAD-on-Restorations (Lithium-Disilicate Fused to Zirconium-Oxide-Framework)

Objective:

Clinical evaluation of all-ceramic lithium-disilicate fused to zirconium-oxide-framework (IPS e.max CAD Veneering Solutions) restorations after 4 years of observation.

Method:

25 CAD-on-restorations (IPS e.max CAD HT fused to IPS e.max ZirCAD, Ivoclar Vivadent, Schaan, FL) were manufactured using a new CAD/CAM-methodology (Cerec v.3.80, Sirona, Germany) in combination with an innovative ceramic–fusing-process (Ivomix and IPS e.max CAD Crystall./Connect, Ivoclar Vivadent). The restorations included tooth- and implant retained crowns (n=20) and 3-unit-bridges (n=5). All CAD-on-restorations were cemented conventionally and examined after a clinical observation period of 4 years by means of FDI criteria for evaluation of indirect restorations (Hickel et al. 2010). The evaluation contains esthetic (A), functional (B) and biological (C) properties.

Results:

After 4 years of clinical observation all CAD-on-restorations were scored “excellent” to “good” relative to the esthetic, functional and biological properties which were examined. One crown could not be examined due to a loosening of a core build up of an endodontic treated tooth (= 1drop-out).  

Conclusion:

The clinical study showed that CAD-on restorations combine high strength with natural appearing esthetics. Neither a chipping nor a fracture could be detected. This stands in contrast to relatively high chipping rates reported in literature for conventional veneered zirconium-oxide-framework (Heintze and Rousson 2010). Due to occlusal adjustment after cementation and 4 years of occlusal function, 67% of the restorations showed small areas with silk-mat luster (scored “good”). These surfaces could only be detected by closer examination. In summary, all-ceramic CAD-on-restorations fabricated of IPS e.max CAD fused to IPS e.max ZirCAD seem perfectly indicated for tooth- and implant retained crowns and 3-unit-bridges. These findings were in accordance to the 12, 24 and 36 month data, presented previously.