title: Time-efficiency analysis of the treatment with monolithic implant crowns in a digital workflow: a randomized controlled trial.
abstract: OBJECTIVE
  The aim of the randomized controlled trial was to analyze time-efficiency of a treatment with implant crowns made of monolithic lithium disilicate (LS2) plus titanium base vs. porcelain fuse to zirconium dioxide (ZrO2) in a digital workflow.
  
  
  METHODS
  Twenty study participants were included for single-tooth replacement in premolar and molar sites. Baseline was the start of the prosthetic treatment. All patients received transocclusal screw-retained implant reconstructions on a soft tissue level-type implant. The 3D implant position was captured with intraoral optical scanning (IOS). After randomization, ten patients were restored with CAD-/CAM-produced monolithic LS2-crowns bonded to prefabricated titanium abutments without any physical models (test), and ten patients with CAD-/CAM-fabricated ZrO2-suprastructures and hand-layered ceramic veneering with milled master models (control). Every single clinical and laboratory work step was timed in minutes and then analyzed for time-efficiency with Wilcoxon Rank Sum Tests. Direct costs were assessed for laboratory fees for first line production in Swiss Francs (CHF).
  
  
  RESULTS
  Two clinical appointments were necessary for IOS and seating of all implant crowns. The mean total production time, as the sum of clinical plus laboratory work steps, was significantly different, resulting in 75.3 min (SD ± 2.1) for test and 156.6 min (SD ± 4.6) for control [P = 0.0001]. Analysis for clinical treatment sessions showed a significantly shorter mean chair time for the complete digital workflow of 20.8 min (SD ± 0.3) compared to 24.1 min (SD ± 1.1) [P = 0.001]. Even more obvious were the results for the mean laboratory work time with a significant reduction of 54.5 min (SD ± 4.9) vs. 132.5 min (SD ± 8.7), respectively [P = 0.0001].
  
  
  CONCLUSIONS
  The test workflow was more time-efficient than the controls for implant-supported crowns; notably, laboratory fabrication steps could be effectively shortened with the digital process of monolithic LS2 plus titanium base resulting in more than 30% reduced overall treatment costs.
authors: Section for Digital Reconstructive Technology & Implant Dentistry [DiRecT+ID], School of Dental Medicine, University of Bern, Bern, Switzerland. tim.joda@zmk.unibe.ch.
authors: Tim
authors: T
authors: Joda
authors: Department of Reconstructive Dentistry & Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors: Urs
authors: U
authors: Brägger
mesh_terms: D017076:Computer-Aided Design; D003442:Crowns; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013996:Time and Motion Studies; D014025:Titanium; D057188:Workflow; D015040:Zirconium
chemical_list: C493120:lithia disilicate; D003776:Dental Porcelain; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
keywords: dental crown; dental implant; digital workflow; economics; time-efficiency