Randomized Clinical Trial comparing clinical adjustment times of CAD/CAM screw-retained posterior crowns on ti-base abutments created with digital or conventional impressions. One-year follow-up.

Abstract

ObjectivesThe purpose of this randomized clinical trial was to compare the required time of potential clinical adjustments of posterior screw‐retained monolithic zirconia implant retained crowns based on intraoral optical scanning (IOS) or conventional impressions.Materials and methodsPatients with posterior tissue level implants (Straumann RN) replacing solitary teeth were recruited. Of all patients, impressions were taken with both an IOS (3M™ TDS) and a conventional (polyether) pick‐up impression. Randomization was performed after impression taking and patients were to receive either a crown based on the digital or the conventional impression. The time required for adjustments at placement was recorded. Additionally, restoration survival and mechanical complications with a follow‐up of one year were documented.ResultsThirty two patients with 45 implants were included: 23 restorations in the test (IOS) and 22 in the control (conventional) group. The average adjustment time was 3.35 min (SD ± 3.38, range: 0–11 min) for the digital versus 6.09 min (SD ± 4.63, range: 0–18 min) for the conventional impressions (p = .039). A proper fit (no adjustments required) was achieved 39,1% in the digital and 18,2% conventional group respectively. All 45 restorations could be placed within the two planned appointments and only two minor mechanical complications occurred during the first year of function.ConclusionsThe use of IOS resulted in shorter adjustment times at try‐in than conventional impressions for solitary CAD/CAM implant restorations. Screw‐retained solitary monolithic zirconia restorations on ti‐base abutments show low complication‐ and survival rates in the short term.