Prospektive Studie zum Vergleich unterschiedlicher Strategien zur Zementierung von monolithischen Zirkonoxidkronen
Clinical evaluation of monolithic zirconia crowns luted with two different resin cements: 6-month results
by Carl Jonas Jochheim
Date of Examination:2025-04-24
Date of issue:2025-03-25
Advisor:Prof. Dr. Matthias Rödiger
Referee:Prof. Dr. Matthias Rödiger
Referee:Prof. Dr. Tina Rödig
Persistent Address:
http://dx.doi.org/10.53846/goediss-11168
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Abstract
English
Zirconia is often used for the fabrication of single crowns (SCs) and other fixed dental prostheses (FDPs) due to its mechanical properties, aesthetics, and excellent biocompatibility (Barão et al. 2010; Manicone et al. 2007; Miyazaki et al. 2013). In several clinical studies zirconia-based SCs show comparable survival and success rates to metal-ceramic FDPs (Pjetursson et al. 2018; Rinke et al. 2016; Sailer et al. 2015; Vigolo und Mutinelli 2012). However, due to its high opacity, veneering with less solid feldspar or glass ceramics is necessary to achieve an aesthetically pleasing overall result (Urapepon und Taenguthai 2015). Similar to metal-ceramic FDPs chipping of the veneering ceramic represents the majority of the technical complications in veneered zirconia FDPs (Schley et al. 2010; Wolfart et al. 2009). To overcome this problem the use of monolithic zirconia FDPs has been introduced. Since there is no need for space of the veneering material only minimal tooth reduction is required (Nakamura et al. 2015). Additionally, the absence of the veneer drastically reduces the occurrence of chipping (Bomicke et al. 2017; Sulaiman et al. 2020; Waldecker et al. 2022). A distinction is now made between four generations of zirconium oxide, which differ in their yttrium content and the addition of aluminum oxide. An increasing yttrium content results in an increase in translucency with a simultaneous reduction in flexural strength (Kolakarnprasert et al. 2019). To address this conflict of objectives, new multilayer materials are being developed that mimic the translucency and color gradient of natural teeth through a hybrid structure while still maintaining good mechanical properties (Pereira et al. 2018; Ueda et al. 2015). Although high-strength materials like zirconia can be luted conventionally the highest bond strength can only be achieved using resin cements (Blatz et al. 2018; Hill und Lott 2011). Similar to adhesive systems used for bonding direct dental restorations, resin cements also come with different application protocols (Perdigao 2020). Some resin cements require the use of an additional adhesive system while others function self-adhesive without any additional steps (Ferracane et al. 2011; Scotti et al. 2017). Adhesive systems that are used in self-etch mode (SE) are often associated with a lower incidence of postoperative hypersensitivity compared to systems that require the use of phosphoric acid as an etching agent. This is thought to be due to the stronger corrosive effect of the phosphoric acid (30%-40%) used in the total-etch (TE) approach (Blatz et al. 2013; Shetty et al. 2012; Yousaf et al. 2014). While various clinical studies suggest that there is no difference in the occurrence of postoperative hypersensitivity between SE and TE adhesive systems for bonding direct restorations (Bekes et al. 2007; Javed et al. 2024; Perdigao et al. 2003; Yamauchi et al. 2019) there is still very limited data comparing both approaches for bonding FDPs. Furthermore, despite the wide use of multi-layered zirconia systems there are very few clinical trials on long-term performance. Therefore, the objective of this study was to evaluate the survival and success of monolithic SCs manufactured with most recent multi-layered zirconia systems and luted with a self-adhesive resin cement and a resin cement using the TE approach. The null hypothesis was that monolithic zirconia SCs show no significant difference in survival and success using the two different luting protocols. It was also assessed if the clinical outcome is influenced by the position of the restoration (anterior versus posterior) or the practitioner (dental student versus dentist).
Keywords: zirconia; crowns; luting; dental
