Randomized controlled trial to compare the clinical performance of two self-adhesive resin cements when used with a fiber post and core build-up in endodontically treated teeth

INTERVENTION: Group 1: 3M™ RelyX™ Universal for luting of the fiber post 1.treatment visit approx. 1h: Preparation of post space and insertion of fiber post 3M™RelyX™ Fiber Post 3D using luting agent 3M™ RelyX™ Universal. Afterwards the core build‐up will be done with Filtek One Bulk Fill. After an intraoral scan the provisional crown will be placed. 2. treatment visit approx. 30 min: Permanent crown restoration placement. It will take place latest 30 days after 1. treatment visit 3.‐5. control visit approx. 15 min: During the control visits the respective teeth will be checked i.a.for marginal adaptation , tooth mobility and apical health. Group 2: 3M™ RelyX™ Unicem 2 Automi Xfor luting of the fiber post 1.treatment visit approx. 1h: Preparation of post space and insertion of fiber post 3M™RelyX™ Fiber Post 3D using luting agent 3M™ RelyX™ Unicem 2 Automix. Afterwards the core build‐up will be done with Filtek One Bulk Fill. After an intraoral scan the provisional crown will be placed. 2. treatment visit approx. 30 min: Permanent crown restoration placement. It will take place latest 30 days after 1. treatment visit 3.‐5. control visit approx. 15 min: During the control visits the respective teeth will be checked i.a.for marginal adaptation , tooth mobility and apical health. CONDITION: ; K08 Other disorders of teeth and supporting structures PRIMARY OUTCOME: The primary endpoint will be the retention rate of the glass‐fiber post (post in situ) at 2 years. SECONDARY OUTCOME: Retention rate of the glass‐fiber post (post in situ) at 6 months, 1 year, 3 years (optional), 4 years, (optional), and 5 years (optional) INCLUSION CRITERIA: 1 Subject is at least 18 or older at time of consent. 2 Subject is able to provide their own informed consent. 3 Subject is willing to return for follow‐up examination for at least 5 years 4 Subject needs an indirect crown or 3‐unit bridge restoration 5 Subject has a tooth with one or less cavity walls of the anatomical crown remaining 6 Subject’s tooth has a residual root canal thickness at the orifice of more than 1 mm 7 Subject’s tooth is symptom free with a root canal filling without a radiologically visible periapical lesion. 8 Subject’s tooth has the possibility to prep a 2 mm ferrule 9 Subject’s tooth has a minimum of 8 mm post length within the root canal, with a minimum of 4 mm apical root canal filling 10 Subject’s tooth has no or treated periodontitis with maximum probing depth of 4 mm and no bleeding on probing 11 Subject’s tooth mobility is not more than score II 12 Subject’s tooth has at least one antagonist