With 3D printing, you can provide chairside ceramic crowns to more patients for a fraction of the cost of other in-office methods. This guide will walk you through the process of data gathering, design, fabrication, preparation, and placement.

Crown Workflow at a High Level

1. Capture Data and Tooth Prep

• Pre-prep scans of the patient (if necessary)
• Tooth preparation
• Post prep scans

2. Plan Treatment

• Design specifics for consideration and best success for in office design
• Submitting Treatment Request for out of office design
• Reviewing and Approving completed design

3. Create Print Job

• Importing into RayWare,
• Verifying setup
• Send to printer

4. 3D Print

• Preparing printer
• Starting the Print Job

5. Clean

• Removal from the build platform
• Removal of supports
• Cleaning with IPA

6. Post Cure Prosthetic

• Using Pro Cure 2
• Using Pro Cure

7. Rinse with IPA

• Second cleaning with IPA

8. Prepare for Placement

• Smoothen the Prosthetic
• Characterize
• Disinfect and Deliver

9. Luting the Crown

• Recommended luting protocol

Workflow Deep Dive

Here we will dive into the recommended Crown workflow into a bit more detail, offering tips and tricks for best success based on real world results.

1. Data Capture and Tooth Prep

During the initial consultation, the patient will be anesthetized and any existing restorations are evaluated. 

Pre-prep Scans

• Digital X-ray
  • Capture an X-ray of the current tooth for documentation and to maximize your anatomical understanding of the patient’s anatomy.
• Intraoral Scans
  • Before the patient is numb, use an intraoral scanner to capture the opposing arch as well as a bite scan. These points of data will be used during the design phase.
  • Intraoral scans should be exported from your scanner in occlusion if using AI Crown

Pro Tip: Pre-op scans are only necessary if you are designing in office. If using SprintRay Cloud Design, it is not necessary to capture this data

Prep Tooth

Evenly reduce the tooth while observing the minimum thickness, creating a circular shoulder with rounded inner edges. Always consult the IFU for the material you’re using. The below are best
practice guidelines when prepping for a 3D printed crown.

Minimum Shoulder width: 0.5 mm (500µm) incisal, 1 mm occlusal

Minimum Vestibular or lingual reduction: 1 mm for anterior, 1 mm for posterior teeth

Incisal edge: 1 mm

For best results, all of the internal finish line angles should have gentle rounded edges or chamfers. Knife or Feathered edges should be avoided for the best accuracy and marginal fit.

Pro Tip: If your intraoral scanner has a High Resolution or HD mode, leaving that setting enabled for scanning the prepped tooth can help give better defined and crisper margin for your prep

For complex or esthetic cases, it is recommended to take photos of the patient when chairside for more accurate color and anatomy matching.

Post Prep Scans

Once you’ve prepped the tooth, it’s time to capture the prepped area and surrounding anatomy.
Take a detailed intraoral scan of the prepped area, as well as the adjacent teeth and gums. This
data will be used in designing the crown.

Before scanning, retract the gum surrounding the prepped tooth, as you’ll need to capture the margin around the prepped area for a good scan.

Pro Tip: Make sure to remove blood and saliva from the affected area
before scanning.

2. Plan Treatment

For Out of Office Design with SprintRay Cloud Design, once the tooth prep is complete and you’ve captured all the necessary data, it’s time to submit for an AI design through SprintRay Cloud. 

Using SprintRay Cloud Design

To submit a design request, visit dashboard.sprintray.com and sign in with your SprintRay account. Select or add your patient, then choose the ‘Crown’ treatment type. Follow the prompts on the screen to upload all the files you gathered during the Data Capture portion.

Thanks to AI technology, you’ll receive a crown design in just a few minutes. Review the design and approve or request a redesign. If your case involves a difficult path of insertion or has other complexities, you may request an expert design, but this will take up to 24 hours. When you approve your design, you’ll be able to download and send it to print.

In Office Design

For in office design, always refer to the IFU for the recommended design parameters for the material you are using.

3. Create a Print Job

Once you’ve approved your design, it’s time to bring your crown to life. If you used SprintRay Cloud Design to create your model, it’s time to bring it into RayWare and prepare it for 3D printing.

Pro Tip: The fastest way to print a crown is with the SprintRay Crown Kit for Pro S. Though not required, we highly recommend the Crown Kit as it saves resin and drastically improves print speed.

Creating a Print Job

Navigate to RayWare Cloud, then start a new print job. Select Crown & Bridge as the job type, then select the printer you’ll use for this job. Select the Crown Kit platform for maximum speed and minimum material waste. For definitive crowns, we recommend SprintRay Ceramic Crown in the shade best suited for your patient. 

Once you upload or import your file, RayWare will automatically orient your model and generate
the ideal support structures

Once your crowns are ready, you can send to any compatible printer that is connected to the same SprintRay Account you are using for Cloud Design and RayWare Cloud.

Pro Tip: Supports should never be placed on the intaglio surface or the margin shoulder, as fitment issues will occur. If you are using RayWare Desktop, you will need to orient the crown STL so that the occlusal surface is facing the platform.

4. 3D Print

Preparing the Printer

It’s time to prepare your 3D printer to fabricate the crown and begin the printing process. The amount of time required for printing will increase if not using the Crown Kit.

Install the Crown Kit or your regular platform and resin tank, following the onscreen prompts to set up.

Once installed, complete the following checklist to make sure your printer is ready:

1. Check that the Crown Kit build plate is attached, clean, and locked
2. Check that the Crown Kit resin tank is seated in its cradle
3. Make sure the resin is filled up to the max line in the tank
4. Use the small squeegee included with the crown kit to mix

Starting the Print

On the printer touchscreen, go to the Queue tab and locate your crown print job. Select Start Print. It may take a few minutes before the printer arm starts to lower, depending on whether or not the resin tank and/or build platform need to be heated up.

You can view the progress of your print on the printer’s touchscreen, including how much time is
left before your job is complete. This information can also be viewed via our cloud Dashboard and on RayWare Cloud.

5. Clean

Remove from Build Platform

Unlock the build platform and gently pull it toward you to release it from the printer. By twisting the prosthetic, you should be able to remove it from the build platform by hand. If it doesn’t release easily, place the platform against a hard surface and use the print removal tool to scrape it off.

Remove Supports

The support structures in RayWare Cloud are specifically designed to twist away from the model by hand. If you have any supports remaining on the prosthetic, use flush cutters to clip them off. Don’t worry if there are still small stubs left on the model, you’ll remove those later.

First Clean

Resins with high ceramic content develop a chalky surface finish if left in contact with IPA for too
long, which requires sandblasting to remove. For most clinics, we recommend washing high ceramic containing resins like Ceramic Crown by hand.

Start by filling a small bowl with ~½ inch (~13mm) of 91% or higher Isopropyl Alcohol (IPA). Then, using a soft, clean shop towel or similar to remove as much liquid resin from the surface of the model as possible

Use a spray bottle with clean IPA and micro brush applicators or cotton swabs to thoroughly clean the intaglio socket. Submerge the crown in the small bowl of IPA for no longer than 30 seconds, and repeat the process of cleaning the intaglio socket with the brushes. Use compressed air to thoroughly remove any IPA residue once complete.

Pro Tip: Do not let IPA stand on the surface of the prosthetic for more than 30 seconds, otherwise it will develop a chalky surface finish.

6. Post cure Prosthetic

Place in Pro Cure 2

To optimize mechanical properties and ensure biocompatibility, your printed crowns must be fully cured.

Place the crown in ProCure 2. On the touchscreen, select the curing profile for the resin you used
to print the prosthetic. If you’re only curing a few crowns at once, place them in the center and
select Bolt Mode curing for the fastest results.

Pro Tip: Users of the original Pro Cure will need to use a Custom Profile for 60 minutes at 60°C

7. Rinse with IPA

Secondary Clean

After the post curing process is completed, the crowns will need to be washed a second time in fresh IPA, utilizing the same method as used previously. Submerge the crown in IPA within a small bowl and brush all surfaces, then remove from IPA and wipe off the surface with shop towel. Use compressed air to thoroughly dry the prosthetic.

Pro Tip:  This secondary wash is critical! This second wash removes any remaining uncured resin or contaminants to ensure proper bonding of the permanent cement and longevity.

8. Prepare for Placement

Before placing the crown, you’ll need to smoothen off any imperfections left by support structures, then characterize.

Smoothen the Prosthetic

Use a fine lab carbide bur or a red Scotch-Brite™ Fuzzies attachment to remove remaining stubs leftover by the support structures until the surface is smooth and uniform.

Characterize

Polish Workflow:

1. Prepolish

• Tool: Lab handpiece
• Polishing Wheel: Meisinger Pink Polisher (9769M-170)
• Technique: Light, consistent pressure
• Speed: 7000-10,000 rpm

Apply light, consistent pressure across all surfaces except the intaglio.

2. High Shine

• Tool: Lab handpiece
• Polishing Wheel: Meisinger Brown Polisher (9790-170)
• Technique: Light, consistent pressure
• Speed: 10,000 rpm

Shine all surfaces of the restoration except the intaglio.

3. High Gloss

• Tool: Cotton buff wheel
• Polishing Wheel: Meisinger Cotton Wheel (150-220)
• Bar: Hatho Polistar Pink bar, Keystone (670546)
• Technique: Consistent pressure

Use polishing compound and cotton wheel to achieve a high gloss on all surfaces except the
intaglio.

Glaze Workflow

1. Prepare

• Tool: IPA and compressed air
• Technique: Clean and dry

Spray the crown with IPA to clean the surface and dry completely with compressed air.

2. Apply

• Tool: Brush and glaze
• Technique: Thin, even coats

Shake bottle thoroughly before use and dispense into a dispensing dish. Apply thinly on the crown
surface with a brush. If applying a second coat of glaze, use an intermediate (short) cure before applying the second coat.

3. Light Cure

• Tool: Handheld curing device with 400-430nm wavelength
  Technique: Light exposure on all surfaces

Use a handheld curing device at an approximate distance of 1cm. Cure each coated surface,
repeating as needed to fully cure any undercuts or areas in shadow.

Note: OptiGlaze cannot be fully cured with ProCure 2; use ProCure 1 or a handheld curing light
with a wavelength of 400-430nm

Pro Tip: Only UV cured stains and glazes should be used with 3D printed restorations. Traditional kiln fired glazes should never be used, as it will damage the printed model! Always refer to the stain and glaze manufacturer's IFU for proper curing techniques

Sterilization

Disinfect the crown using a steamer if possible, then brush lightly with dish soap to disinfect the crown before placement. Ensure that the crown is completely dry before cementation. You can sandblast the intaglio surface of the restoration to improve bond strength.

Cementation

The finished permanent restorations can be cemented using a dual cure resin cement (Panavia V5 recommended). The use of an adhesive primer (e.g. Clearfil) on the intaglio surface of the crown should comply with manufacturer instructions. Please see the Ceramic Crown Cementation Guide for validation of common cementation workflows.

Pro Tip: Follow the manufacturer instructions for use of the luting agent and ensure compatibility with 3D printed crowns. Note that the prep may require etching or priming with certain cements. Do not etch crowns with phosphoric or hydrofluoric acid.

9. Lute the Crown

Follow the SprintRay recommended workflow to maximize the strength between the resin cement
and Ceramic Crown.

The Luting Protocol below elaborates on the top recommended workflow for maximum bond strength which was provided by Panavia™ V5 Resin Cement with Clearfil™ Ceramic Primer Plus. Ceramic Crown is compatible with a wide range of cements and primers.

Luting Protocol

• Check the fit of the restoration on the prep. Make any necessary adjustments to the crown to ensure a proper fit.

• Clean and prepare bonding surfaces of the tooth and crown. This involves removing any residue from the crown by washing thoroughly with IPA and preferably sandblasting the intaglio surface to create roughness for improved bond strength.

• Apply Clearfil™ Ceramic Primer Plus to the intaglio surface of the crown along the bonding interface. After application, dry the entire adherent surface by blowing with air.

•  Clean the surfaces of the prepped tooth or Ti Base
  • For Ti Base:
    
    • Follow the manufacturer’s instructions for Clearfil Ceramic Primer Plus for priming the Ti base.

• •  
  • For Prepped Tooth:
    • Follow manufacturer's instructions for Panvia™ V5 Tooth Primer for priming of the prepped tooth.

• Apply the cement to the inside surface of the crown, making sure to distribute it evenly. Place the crown onto the prepped tooth, using gentle pressure to ensure that it is fully seated.

• Remove any excess cement from the margins of the crown and light cure for 5 seconds. Then remove any excess cement with a proper dental hand instrument. Ask patient to bite softly and hold in occlusion for 3 minutes for initial polymerization.

• Perform a final check of the crown to ensure that it is fully seated, the margins are sealed, and the occlusion is correct.

Note: it is important to follow the manufacturer's instructions for the specific cement being used and to utilize proper techniques to ensure a strong bond.

 

Now you are all done!