Full-Digital Workflow in Single-Tooth Implant Rehabilitation

The digital workflow in dental implantology has been used for planning the cases with the intraoral scanners and computer tomography, together helping clinicians to be more accurate and precise. Today, thanks to digital technology clinicians can plan from surgical to the final prosthesis using 3D models and cad-cam machines. The aim of this research is to validate the full digital workflow for the single-tooth implant rehabilitation. A total of 19 patients (22 implants) were included in the present study with mean follow-up time of 2 years. A full-digital workflow was performed on each patient through the design and printing of a surgical guide, the taking of the impression with an intraoral scanner and the CAD-CAM design of the crowns.

Study design The present study was a retrospective case series conducted in one clinical center in accordance with the Good Clinical Practice Guidelines (GCPs) following the recommendations of the World Medical Association Declaration of Helsinki-ethical principles for medical research involving human subjects as revised in Fortaleza (2013).

All patients were informed about the benefits and the possible risks of a fully digital workflow and its alternatives finally a signed written consent was obtained. Subject population

The current retrospective study was performed in a private clinic in Rome, Italy, where all patients treated by the same operator between January 2017 and June 2020 were consecutively enrolled:

* Patients older than 18 years
* Patients in good health (Asa 1 or Asa 2)
* Patients with healthy periodontium (probing pocket depth ≤ 4 mm, no bleeding on probing)
* Patients not requiring bone augmentation procedures Patients requiring a single implant supported reconstructions were included in the present study.

Surgical and prosthetic workflow For all patients included in the study, a digital impression was taken using an intraoral scanner (CS3600, Carestream Dental, Atlanta, Ga). During the same day, a CBCT (CS9000 3D, Carestream Dental, Atlanta, Ga) exam was performed on the mandibular or maxillary jaw with the missing tooth. The stl. and the dicom. files were then superimposed to allow the surgical planning (RealGuide, 3Diemme, Cantù, Italy).

One week after planning, implant insertion was performed after the elevation of a flap with a papilla preservation technique. Once designed, the flap was dis-epitelized using a diamond bur. Then it was elevated and reflected to increase the volume on the buccal side and exposed the bone surface. After this point, the implant (Sweden \& Martina, Padua, Italy) was inserted, and another digital impression was taken.

Sutures 6.0 were positioned (monofilament-polyglecaprone suture, Surgiclryl-Monofast ®SMI-Belgium) after healing abutment positioning to stabilize the soft tissues.

In the mean, time, the file of the impression was sent to technician and the final abutment and the provisional were designed and manufactured using cad-cam technology. One week thereafter, definitive abutment was positioned and screwed at 25N/cm Provisional restoration was then cemented using provisional cement (Temp Bond, Kerr Sybron Dental Specialities, Washington, DC, USA) removing all the possible occlusal contacts both in protrusive and in lateral positions.

Sutures were removed 2 weeks postoperative. Three months thereafter, once osteointegration was obtained, definitive zirconia restoration was positioned and cemented.

Eventual deficiencies of the prosthetic rehabilitation at the time of provisional restoration (contact points, esthetics) were noticed and fixed directly adding composite. In all these cases, a new impression after soft tissue maturation was performed and strategically, a new crown in PMMA was designed and realized. Final check before producing the zirconia element was performed positioning the crown on the abutment.

Eligibility Criteria:
Inclusion Criteria:

* Patients older than 18 years
* Patients in good health (Asa 1 or Asa 2)
* Patients with healthy periodontium (probing pocket depth ≤ 4 mm, no bleeding on probing)

Exclusion Criteria:

* Patients requiring bone augmentation procedures