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Les Kalman is Assistant Professor of Restorative Dentistry and Educational Lead for Persevering with Dental Training at Western College’s Schulich Faculty of Medication & Dentistry. He will likely be collaborating in Additive Manufacturing Methods 2022, Panel 2: Enhancing the affected person expertise with 3D printing.
Introduction
Dental implants stay the gold commonplace for the substitute of a lacking tooth or tooth. If all of the tooth in a single arch are totally lacking (edentulous) then rehabilitation with implants gives sufferers an enchancment in perform, aesthetics and high quality of life. Implant bars are a predictable and cost-effective choice, the place the bar helps and retains the denture, as a substitute of resting on the affected person’s gentle tissues. Implant bars are delivered to sufferers by means of a posh medical workflow and fabricated by means of subtractive manufacturing or milling. The milling course of has its disadvantages, by way of price, effectivity and environmental footprint.
As steel additive manufacturing (AM) matures, it presents a novel alternative for the fabrication of implant bars, which can cut back each the time and price, finally enhancing the accessibility for the therapy. Furthermore, AM could present a extra sustainable strategy, particularly by means of a extra conservative lattice-structured design, lowering dentistry’s environmental footprint. This report explains our workflow developed for the fabrication of additive manufactured stable & lattice-structured titanium alloy dental implant overdenture bars.
Strategies & Supplies
Milled Bar
A dental implant steel bar was sourced from Panthera Dental. This bar was a part of a affected person training mannequin, consisting of the implant bar, mannequin of the affected person’s decrease jaw (mandible) and the simulated gentle tissue (Determine 1). The implant bar was milled from titanium alloy (Ti6Al4V) on a totally robotic CNC machine at a 4.0 manufacturing facility. The bar was monobloc, with no welded areas and no porosity, and had a really correct and passive match with the dental implants on the mannequin. The STL file of the bar was supplied by Panthera Dental.
Determine 1. Affected person gentle tissue mannequin with implants and milled dental implant bar.
Design
The implant bar design file (STL) was reviewed by ADEISS (London, Ontario) to judge the design for additive manufacturing. Assessment for AM decided that the STL design required modifications to include through-holes of two mm in diameter for implant placement, and the general implant bar construction wanted to be thickened to account for AM post-processing the place floor ending was required.
Two implant bar designs have been generated for AM; the primary design was a stable construction to copy a regular implant bar, and the second design included an inner latticed sample inside the bar part. The lattice design was created utilizing commonplace pc aided design (CAD) software program features, with round cross-sectional geometry (Ansys Spaceclaim 3D Modeling Software program) (Figures 2 and 3). Moreover, for the lattice-designed bars, drainage holes of 0.75 mm diameter have been included into the anterior partitions, such that non-consolidated powder from the AM course of may very well be cleaned from the samples in post-processing (Determine 3). The ultimate STL designs for AM have been confirmed to match the size of a comparative milled bar pattern.
Determine 2. Implant bar mannequin with inner lattice sample. (Picture supplied by ADEISS Inc., London, ON, Canada)
Determine 3. Implant bar design with round cross-section inner lattice sample. (Picture supplied by ADEISS Inc., London, ON, Canada)
Selective Laser Melting (3D Printing) and Submit-Processing
STL designs for AM have been ready for printing in medical-grade titanium alloy (Ti6Al4V). Printing was executed utilizing selective laser melting know-how with the Renishaw AM 400 system (Renishaw PLS, Gloucestershire, United Kingdom). The 3D printer makes use of alloy powder inside the vary of 30 – 50 µm in diameter, with a 400W laser of 70 µm diameter, to consolidate the ultimate implant bars inside a 250 mm x 250 mm x 250 mm construct quantity. A complete of 18 implant bars (12 stable, 6 inner lattices) have been fabricated with machine print time of seven hours and 6 minutes.
Following the printing course of, the construct plate with implant bars have been cleaned utilizing compressed air. Air was cycled throughout the construct plate and thru drainage holes till no unfastened powder was additional expelled. Following powder clearance, the implant bars have been uncovered to straightforward warmth therapy in a vacuum furnace, faraway from the construct plate, and floor completed. All implant bars have been processed to a mirror polished end (< 1 µm Ra) utilizing hand tooling (Determine 4). The ultimate processing step included cleansing of all implant bars utilizing ADEISS ultrasonic cleansing strategies to take away any remaining alloy powder and sharpening brokers.
Determine 4. Remaining AM latticed-structured dental implant bar.
Dialogue
The AM workflow fabricated dental implant bars that have been evaluated to be clinically acceptable, primarily based on the match with the unique affected person mannequin and subsequently with the match of a denture (Determine 5). Based mostly on the variety of implant bars that may be fabricated from the construct plate, the time of fabrication and price, the AM fabrication workflow steered benefits over standard milling. Additional analysis is being carried out by means of 4-point testing and will likely be launched within the coming months.
Determine 5. AM implant bar threaded onto dental implants supporting an entire denture.
Conclusion
The AM workflow for each stable and latticed-structured dental implant bars indicated that AM is an appropriate, and maybe a superior, fabrication workflow for implant bars. Additional analysis and metrics are wanted. Workflows that present improved price financial savings, effectivity and sustainability ought to be explored, to not solely enhance the affected person expertise but in addition the sustainability of the career.
Acknowledgements
Panthera Dental supplied the milled implants bars and fashions; all design, manufacturing, and post-processing for AM have been accomplished by the Additive Design in Surgical Options Centre (ADEISS Inc.); Alien Milling Applied sciences supplied the Ivotion denture. This analysis was funded by an Worldwide Congress of Oral Implantologists (ICOI) IDREF grant. Particular because of Dr. Yara Hosein for above and past help.
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