Time Efficiency of Immediate Loading of Full-arch Implant Reconstructions Using Prefabricated Prostheses Located by an Anchor Pin: a Pilot Study.

OBJECTIVE: To investigate the time efficiency of prefabricated prostheses located by an anchor pin stereolithographic attachment system for immediate loading implant reconstruction of completely edentulous jaws and compare it with the conventional protocol. METHODS: Edentulous patients were recruited and randomly assigned into two groups: the full digital workflow group (digital group) and the conventional workflow group (conventional group). In the digital group, a provisional prosthesis was fabricated before surgery using a fully digital workflow and delivered immediately after implant placement. The positioning of the provisional prosthesis was guided precisely by the anchor pin attachment system. In the conventional group, the provisional prosthesis was fabricated after implant placement using a conventional procedure. Clinical and laboratory time efficiency were recorded, and clinician and patient satisfaction were evaluated. RESULTS: Six patients were enrolled in this pilot study and 57 implants were placed following the guided surgery protocol. Of these, 54 were immediately loaded. The total clinical chair time in the digital workflow group was significantly less than that in the conventional workflow group (digital 60.0 ± 13.2 minutes; conventional 106.7 ± 24.7 minutes) (P = 0.045). The total post-surgery procedure took significantly less time in the digital group than the conventional group (digital 202.5 ± 22.5 minutes; conventional 403.7 ± 55.4 minutes) (P = 0.004). The patients' and clinicians' satisfaction with the provisional prostheses was similar in both groups. CONCLUSION: Time efficiency in immediate loading of implant-supported full-arch fixed restorations was improved with prefabricated prostheses located by the anchor-pin-attachment system. Less postoperative chair time was required in the digital group than in the conventional group.

Accuracy of Intraoral Scanning of Edentulous Jaws with and without Resin Markers.

Objective: To evaluate the accuracy of digital models obtained from intraoral scanning of edentulous maxilla and mandible models with and without resin markers. Methods: A pair of standard edentulous models were scanned using a laboratory scanner and saved as reference models. The edentulous models were fixed onto a phantom head and scanned with an intraoral scanner (IOS) five times each. Six resin markers were attached on the maxilla model and two on the mandible model, and another five intraoral scans were taken of each model. The scanning time and number of images were recorded. The digital models obtained using the IOS were superimposed on the reference models using image processing software. The trueness and precision of the models made using the IOS were evaluated, and the scanning time and number of images were also compared. Results: The average trueness and precision of the IOS in the maxilla model with resin markers were 135.50 ± 36.28 µm and 254.55 ± 40.62 µm, respectively, while those in the mandible were 161.40 ± 55.45 µm and 368.75 ± 91.03 µm, respectively. Placing resin markers on the edentulous maxilla and mandible did not improve the trueness of the IOS, but placing resin markers on the edentulous maxilla improved the precision and scanning efficiency. However, placing resin markers on the buccal shelf of the edentulous mandible decreased the precision and increased the scanning time. Conclusion: Resin markers placed on the hard palate of edentulous maxillae could improve the precision of the IOS and improve scanning efficiency. However, they did not affect the trueness of the IOS for edentulous maxillae or mandibles.