Statement of problem
A digital workflow in fixed prosthodontics may use a 3D printer to obtain a cast for porcelain application. Standards exist that define the accuracy of traditional casts, but the accuracy requirements of 3D-printed casts have not been defined.
The purpose of this retrospective study was to investigate how the accuracy of 3D-printed casts affected prosthesis fit and whether they correctly reproduced interproximal contacts.
Material and methods
Copings with different die spacings were used to test different 3D-printed casts of the same dental arch. The accuracy of the 3D casts was assessed by imaging and comparing the resulting standard tessellation language (STL) files with the original through a matching software program. Accuracy scores were then correlated with a score measuring how well the copings fit the casts. The first data set was obtained from a patient receiving restoration of the 4 maxillary incisors. The teeth were prepared, the dental arch was imaged intraorally, and 10 resin casts were printed with four 3D printers. Two sets of 4 zirconia test copings were prepared, and 3 clinicians assessed their fit on each cast. A further set of casts was created from a second patient requiring prosthetic restoration for 5 adjacent teeth to assess whether undersizing affected the best fit of the copings on their dies.
The clinical scores and accuracy scores did not correlate. The results suggested that printed dies showing a certain degree of undersizing might provide a better fit than those showing better correspondence to the actual anatomic structure. The oversized dies were the worst. Only 7 of 17 casts being assessed were deemed suitable for veneering of the copings. The undersized casts tested clinically better than casts printed by using the same printer under standard settings.
This retrospective study indicated that 3D-printed casts that do not allow copings to fit appropriately usually show mean excess oversizing. Axially undersizing the printed dies on casts might allow a better fit of copings to be veneered.
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- Digital versus conventional implant impressions for edentulous patients: accuracy outcomes.Clin Oral Implants Res. 2016; 27: 465-472
- Conventional versus digital impressions for “all-on-four” restorations.Int J Oral Maxillofac Implants. 2016; 31: 324-330
- Accuracy of digital impressions of multiple dental implants: an in vitro study.Clin Oral Implants Res. 2017; 28: 648-653
- Digital workflow for fixed implant rehabilitation of an extremely atrophic edentulous mandible in three appointments.J Esthet Restor Dent. 2017; 29: 178-188
- Digital technology in fixed implant prosthodontics.Periodontol 2000. 2017; 73: 178-192
- ISO 6873. Dentistry - gypsum products.International Organization for Standardization, Geneva2013 (Available at:)http://www.iso.org/iso/home.htmlDate accessed: January 6, 2021
- ANSI/ADA Standard No. 25 dental gypsum products - ADA25-2015D.(Available at:)http://ebusiness.ada.org/productcatalog/75977/Prosthodontic-Materials/ANSIADA-Standard-No-25-Dental-Gypsum-Products/ADA25-2015DDate accessed: July 6, 2019
- Computer aided-designed, 3-dimensionally printed porous tissue bioscaffolds for craniofacial soft tissue reconstruction.Otolaryngol Head Neck Surg. 2015; 152: 57-62
- Digital vs. conventional full-arch implant impressions: a comparative study.Clin Oral Implants Res. 2017; 28: 1360-1367
- An in vitro study of factors influencing the performance of digital intraoral impressions operating on active wavefront sampling technology with multiple implants in the edentulous maxilla.J Prosthodont. 2017; 26: 650-655
- Precision and trueness of dental models manufactured with different 3-dimensional printing techniques.Am J Orthod Dentofacial Orthop. 2018; 153: 144-153
- Accuracy and reproducibility of dental replica models reconstructed by different rapid prototyping techniques.Am J Orthod Dentofacial Orthop. 2014; 145: 108-115
- Zirconia in biomedical applications.Expert Rev Med Devices. 2016; 13: 945-963
- CEREC chairside system to register and design the occlusion in restorative dentistry: a systematic literature review.J Esthet Restor Dent. 2016; 28: 208-220
- Effect of virtual articulator settings on occlusal morphology of CAD/CAM restorations.Int J Comput Dent. 2007; 10: 171-185
- Fracture resistance of monolithic zirconia molar crowns with reduced thickness.Acta Odontol Scand. 2015; 73: 602-608
- Recent advances in dental optics - part I: 3D intraoral scanners for restorative dentistry.Opt Lasers Eng. 2014; 54: 203-221
- Diagnostic accuracy of impression-free digital models.Am J Orthod Dentofacial Orthop. 2013; 144: 916-922
- Use of intraoral digital scanning for a CAD/CAM-fabricated milled bar and superstructure framework for an implant-supported, removable complete dental prosthesis.J Prosthet Dent. 2015; 113: 509-515
- Accuracy of complete-arch dental impressions: a new method of measuring trueness and precision.J Prosthet Dent. 2013; 109: 121-128
- Generation and evaluation of 3D digital casts of maxillary defects based on multisource data registration: a pilot clinical study.J Prosthet Dent. 2017; 118: 790-795
- Surgical and prosthetic dental rehabilitation through a complete digital workflow - a case report.Int J Comput Dent. 2016; 19: 341-349
- 3D Rapid prototyping for otolaryngology-head and neck surgery: applications in image-guidance, surgical simulation and patient-specific modeling.PLoS One. 2015; 10: e0136370
- Use of 3-D stereolithographic models in oral and maxillofacial surgery.J Maxillofac Oral Surg. 2011; 10: 6-13
- Accuracy of implant impressions for partially and completely edentulous patients: a systematic review.Int J Oral Maxillofac Implants. 2014; 29: 836-845
Published online: January 14, 2021
Conflict of interest: Eng. D.P. is an employee of IDI Evolution s.r.l. which owns one of the 3D printers used in this study. Dr D.A.D.S. and Dr G.B.G. are consultants for IDI Evolution s.r.l.
© 2020 by the Editorial Council for the Journal of Prosthetic Dentistry.