Conventional versus Digital Impressions for Full Arch Screw-Retained Maxillary Rehabilitations: A Randomized Clinical Trial

Abstract

Background: The objective of this study was to compare conventional versus digital impressions for Full-Arch maxillary rehabilitations. Methods: Patients selected for this study were treated with full-arch screw-retained rehabilitations supported by six immediately loaded dental implants. Patients have been scheduled randomly into control (conventional impression group, CIG) and test (digital impression group, DIG) groups respectively for a fully conventional workflow and a fully digital workflow. In both groups, within 24 h, temporary prostheses were delivered. Four months after the implant positioning, the two groups dealt with the fabrication of definitive restorations: conventional pick-up was performed in the control group, and definitive digital impressions were carried out in the test group. The time involved following these two procedures was recorded. Patients underwent intraoral digital radiographs to evaluate the accuracy of the framework-implant connection, check for the presence of voids at the bar-implant connection and measure bone level. Criteria used to assess success at the prosthetic level were the occurrence of prosthetic maintenance, the absence of fractures of the acrylic resin superstructure and voids. Results: A total of 50 patients received immediately loaded prostheses supported by six implants (total 300 implants). A fixture and prosthetic survival rate of 100% was observed. All digital X-ray examinations revealed a bar-implant connection accuracy and no voids. Differences that were not statistically significant (p > 0.05) in marginal bone loss were found between control and test groups. Significantly less time was spent to perform digital impression procedure (p < 0.05). Conclusions: Clinical and radiological results of the test group advocate a satisfactory accuracy and predictability of the intraoral scanner (IOS) to be a reliable alternative in clinical practice for implant full-arch rehabilitations and suggest fabrication of definitive restorations with a successful marginal fit precision.

Keywords: crestal bone loss; digital impression; digital workflow; full-arch rehabilitations; immediate loading; implant success; implant survival; implant-prosthodontic restorations.

Figure 1

Full-arch digital scan with splinted scan bodies.

Figure 2

(a) Intraoral scanning of soft tissues after a 4-month healing time. (b). Scan of the temporary prosthesis with analogs in position.

Figure 3

Matching of soft tissues, scan bodies and virtual models of related components scans.

Figure 4

Precision match of intra and extraoral scan.

Figure 5

Virtual models of the framework and of the superstructure.

Figure 6

CAM output of the framework and of the suprastructure.

Figure 7

Prosthesis finalization in the laboratory.

Figure 8

Definitive intraorally screw-retained restorations.

Figure 9

Panoramic radiograph at follow-up.