Abstract
Statement of problem
Information on the fabrication of metal by selective laser melting (SLM) systems positioned
at different angles is sparse.
Purpose
The purpose of this in vitro study was to evaluate the extent of marginal and internal
gaps in metal copings fabricated at different angles by using an SLM fabrication system.
Material and methods
A master metal model was produced and replicated (N=10) with silicone impressions
and dental stone. Standard tessellation language (STL) files of the 10 coping designs
were then obtained by using a model scanner and a 3D design software program on a
scannable working die. Co-Cr alloy metal copings were fabricated by the SLM fabrication
system at 45, 90, and 180 degrees. The marginal and internal gaps were measured by
the silicone replica technique. The measured data were analyzed by using the nonparametric
Kruskal-Wallis H test (α=.05).
Results
The specimens fabricated at 180 degrees showed the best fit in terms of the marginal
gap, while the worst fit was observed in the specimens fabricated at 90 degrees. Statistically
significant differences were seen among the marginal gaps produced in the 3 groups
(P<.001). In terms of internal fit, the axial wall gap showed the best fit, and the
occlusal gap the worst. The best fit overall was 66 μm at the axial wall of the 180-degree
group, and the worst in the 90-degree group, at 663 μm. Statistically significant
differences were observed between the chamfers, axial walls, and the occlusal gaps
of the 3 groups (P<.001).
Conclusions
Restorations fabricated by using an SLM system at 180 degrees were clinically acceptable.
However, more research is required to investigate the performance of metal copings
produced at 45 and 90 degrees to evaluate their clinical acceptability.
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Journal of Prosthetic DentistryAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- The use of CAD/CAM in dentistry.Dent Clin North Am. 2011; 55: 559-570
- CAD/CAM imaging in dentistry.Curr Opin Dent. 1991; 1: 150-154
- In vitro evaluation of marginal discrepancy of monolithic zirconia restorations fabricated with different CAD-CAM systems.J Prosthet Dent. 2017; 117: 762-766
- Resin-composite blocks for dental CAD/CAM applications.J Dent Res. 2014; 93: 1232-1234
- A 3-dimensional accuracy analysis of chairside CAD/CAM milling processes.J Prosthet Dent. 2014; 112: 1425-1431
- Interference-free toolpath generation using enveloping element for five-axis machining of spatial cam.J Mater Process Technol. 2007; 187: 10-13
- A method to predict the ultimate tensile strength of 3D printing polylactic acid (PLA) materials with different printing orientations.Compos B Eng. 2019; 163: 393-402
- 3D printed versus conventionally cured provisional crown and bridge dental materials.Dent Mater. 2018; 34: 192-200
- Current status of bioinks for micro-extrusion-based 3D bioprinting.Molecules. 2016; 21: 685
- The future of dental devices is digital.Dent Mater. 2012; 28: 3-12
- Internal and marginal fit of cobalt-chromium fixed dental prostheses fabricated with 3 different techniques.J Prosthet Dent. 2015; 114: 686-692
- Evaluation of the mechanical properties and porcelain bond strength of cobalt-chromium dental alloy fabricated by selective laser melting.J Prosthet Dent. 2014; 111: 51-55
- The marginal fit of selective laser melting–fabricated metal crowns: an in vitro study.J Prosthet Dent. 2014; 112: 1437-1440
- Comparison and evaluation of marginal and internal gaps in cobalt–chromium alloy copings fabricated using subtractive and additive manufacturing.J Prosthodont Res. 2018; 62: 56-64
- Numerical investigation and an effective modelling on the selective laser melting (SLM) process with aluminum alloy 6061.Int J Heat Mass Transf. 2015; 80: 288-300
- Three-dimensional evaluation of gaps associated with fixed dental prostheses fabricated with new technologies.J Prosthet Dent. 2014; 112: 1432-1436
- Effects of repeated firing on the marginal accuracy of Co-Cr copings fabricated by selective laser melting.J Prosthet Dent. 2015; 113: 135-139
- Depletion of intracellular ascorbate by the carcinogenic metals nickel and cobalt results in the induction of hypoxic stress.J Biol Chem. 2004; 279: 40337-40344
- Evaluation of marginal and internal gaps of Ni-Cr and Co-Cr alloy copings manufactured by microstereolithography.J Adv Prosthodont. 2017; 9: 176-181
- Nickel-based (Ni-Cr and Ni-Cr-Be) alloys used in dental restorations may be a potential cause for immune-mediated hypersensitivity.Med Hypotheses. 2009; 73: 716-717
- An investigation of dental luting cement solubility as a function of the marginal gap.J Prosthet Dent. 1991; 65: 436-442
- Effect of CNC-milling on the marginal and internal fit of dental ceramics: a pilot study.Dent Mater. 2013; 29: 851-858
- The estimation of cement film thickness by an in vivo technique.Br Dent J. 1971; 131: 107-111
- Cavity design and mathematics: their effect on gaps at the margins of cast restorations.Oper Dent. 1985; 10: 122-137
- A comparison of the marginal fit of In-Ceram, IPS Empress, and Procera crowns.Int J Prosthodont. 1997; 10: 478-484
- Internal and external fit of CAM-made zirconia bridge frameworks-a pilot study.Dtsch Zahnärztl Z. 2006; 61: 38-42
- The effect of preparation designs on the marginal and internal gaps in Cerec3 partial ceramic crowns.J Dent. 2009; 37: 374-382
- Comparison of marginal fit between CAD-CAM and hot-press lithium disilicate crowns.J Prosthet Dent. 2019; 121: 124-128
- Accuracy of marginal fit and axial wall contour for lithium disilicate crowns fabricated using three digital workflows.J Prosthet Dent. 2019; 123: 121-127
- Fit of single tooth zirconia copings: comparison between various manufacturing processes.J Prosthet Dent. 2011; 105: 249-255
- The fit of gold inlays and three ceramic inlay systems: a clinical and in vitro study.Acta Odontol Scand. 1993; 51: 201-206
Article info
Publication history
Published online: February 11, 2021
Identification
Copyright
© 2020 by the Editorial Council for the Journal of Prosthetic Dentistry.
