Success and Survival of e.Max and KHF2 Etched Zirconia Cemented With Resin Cement - a Randomized Controlled Clinical Study

A randomized controlled clinical study that aims to compare success and survival of potassium hydrogen difluoride (KHF2) etched zirconium dioxide and lithium disilicate reinforced glass ceramic cemented to molars/premolares using dual cure resin cement.

The null hypothesis for the study is that zirconium dioxide and lithium disilicate reinforced glass ceramic will retain equally good tooth substance when cemented with resin cement.

Participants are recruited from the student clinic at Faculty of Dentistry, University of Oslo. Patients who fulfill the inclusion criteria 1) age above 18, 2) require restoration on premolar/molar and 3) are able to come to treatment and recall, are informed about the study and invited to participate. Consent to participation are signed by the patient. At any time and for any reason participants can withdraw from the study.

Personal information will be registered in Service for Sensitive Data, which is a platform to collect, store, analyze and share sensitive data. An encoded research file will be kept separate from the patient journal.The content of this file will be patient journal number and classification of the restoration on a four level scale (Californian Dental Association - CDA) for each recall.

A randomizing tool will be used to decide which ceramic restoration each participant will receive. Treatment will be performed by one clinician. The tooth preparation will be with little retention, and preferably supragingival. For cementing the restorations a standardized protocol for a dual cure resin cement will be used.