The demand for tooth-colored dental restorations has increased rapidly within the last few years. Ceramic restorations can often meet these requirements. In dental implantology, zirconia especially—due to its esthetical advantage as well as high flexural strength and outstanding biocompatibility—has gained importance [1]. On the other hand, one-piece zirconia implants are not yet commonly used because the surgical possibilities do not always meet the prosthodontics requirements. Besides, angled one-piece zirconia implants are not yet available. The superstructure can only be cemented to the zirconia implant which may result in remaining excess cement and peri-implant inflammation [2].

Implant and superstructure provide a complex system, which has to withstand oral conditions. Concerning the brittleness of many ceramics, fractures are a greatly feared issue. Therefore, PICNs were developed. They are composed of a ceramic and a composite network and are supposed to combine the advantages of both materials [3]. One of these PICN materials is known under the trade name Vita Enamic (VE) (Vita Zahnfabrik, Bad Säckingen, Germany). It consists of 86 wt% feldspathic ceramic and 14 wt% polymer network. The two networks entirely interpenetrate one another which is supposed to result in a high fracture resistance [4].

Low hardness and high fracture stability differentiate PICNs from conventional feldspathic ceramics [5]. Because of a high elastic modulus [6], PICN crowns on one-piece zirconia implants could absorb forces to prevent the system from fracturing when sustaining oral forces. Recommendations for the material of superstructures on zirconia implants are still lacking, and only one study investigates PICN crowns on these types of implants [5].

Accordingly, this study aimed to examine PICN crowns on one-piece zirconia implants regarding bond strength and surface wear after long-term chewing simulation. The number of cycles during chewing simulation (CS) corresponds roughly to an in vivo load of 5 years [7].