DAMP1: The 1T1T Concept Versus Conventional Implant Loading Protocol

Overview

The One tooth - One time (1T1T) innovative approach is a straightforward and cost-effective protocol to replace a missing tooth in the posterior region (Lambert and Mainjot 2017) (see Appendix). The digital impression of single unit implants right after the implant placement and the direct manufacturing of a Polymer-Infiltrated Ceramic Network (PICN) screw-retained crown allows the delivery of a final tooth in occlusion within the same day. The absence of lab procedures reduces the number of appointments, providing immediate results and high patient satisfaction. The prosthesis material choice is crucial in this procedure. Indeed, PICN high resilience, i.e. damping effect, could reduce peri-implant strain compared to ceramic materials (Magne, Silva et al. 2013) (Maminskas, Puisys et al. 2016), moreover its elastic modulus is close to tooth tissues, while other CAD-CAM composites value is too low and ceramic materials are too high. The rapid milling and manufacturing process, without any firing procedure, and the ease of adjustments (particularly to adjust proximal and occlusal contact points), make also PICNs well-adapted to chair-side systems. The material low stiffness and hardness can improve patient comfort and promote adaptation of the restorations to occlusal relationships with time. The 1T1T approach was presented as a proof of concept in a first international publication using tissue level implants from Straumann, which describes the whole protocol (Lambert and Mainjot 2017). Currently, a case series including 10 teeth is on-course, showing a 100% survival rate of implants and restorations after a 2-yr follow-up. These results are very promising but further clinical research is needed to validate such a protocol on a larger number of patients, on other implant systems as well as to compare this approach to conventional protocols.

The present study is designed as a single center comparative controlled trial. This study aims to compare immediate (1T1T) versus delayed loading with a final PICN screw-retained crown (DL-PICN), performed with CAD-CAM system. A total of 28 consecutive patients (56 teeth) above the age of 18 and presenting two single-unit edentulous space in the posterior region (molars or premolars, upper or lower jaw), will be considered for possible inclusion in the study, according to the inclusion and exclusion criteria (patients with high occlusal stress will be included). The performance of the different protocols will be tested in terms of (1) prostheses and implants survival and success rates following international standards (2) Patient reported outcome measures (PROMs); (3) time and cost. Moreover, restorations and antagonistic teeth wear will be studied trough ex-vivo analysis by profilometry of replica. The evaluations will be carried out at a follow-up period of 7 days, 2, 6 months and then every year up to 5 years. Hypothesis is that the type of loading technique with a final PICN crown (1T1T or DL-PICN) does not influence prostheses and implants survival and success rates, but that 1T1T protocol improves patient-centered outcomes as well as time and cost effectiveness in comparison with DL-PICN. The overall cost of the restoration treatment will be 1600€ (instead of 2100€), which represents a saving of 500€ for the patient.