3D printed temporary crowns and bridges: resins, workflow and tips

Temporary crowns and bridges can be printed within a few hours of scanning: the designed restoration is printed in a temporary restoration resin, washed, post-cured, polished and, if needed, characterized. The most important choice is the resin, based on how long the temporary restoration will stay in the mouth: for a short try-in, basic temporary restoration resins such as SHINING DENT CB11 are suitable, while for a longer period ceramic-filled resins such as SHINING DENT CB12 are the better choice.

When a temporary restoration is worth printing

A printed temporary restoration is made from the same digital design as the final one. This offers several practical advantages:

• shape, occlusion and contacts are planned in advance, so less adjustment is needed chairside;
• the temporary restoration can become a "trial version" of the final one – the approved shape is transferred to the final restoration;
• if the temporary breaks or wears, it can quickly be reprinted;
• many units can be printed at once, for example several multi-unit bridges.

In the lab this is convenient when a long-term provisional phase is needed (implant healing, increasing the vertical dimension, periodontal treatment), and in the clinic when the temporary is to be made on the same day.

Which resin to choose

The IMMT range includes the following resins for temporary and try-in restorations:

If the restoration is to be permanent, choose resins intended for permanent restorations – SHINING DENT CB200, HeyGears LT Crown UV, Detax Freeprint Crown UV or Graphy TC-80DP. We gave an overview of all resins in the article 3D printing resins in dentistry.

How long a temporary restoration can stay in the mouth

Only the instructions for use of the specific resin can answer this question. In product descriptions, manufacturers indicate a direction but not a specific duration: CB11 – for a temporary wearing period, CB12 – for long-term temporary and semi-permanent work, HeyGears Temp For Try-in UV – also for longer temporary use, TN11 – primarily for try-in. Before planning a provisional phase lasting several months, check the permitted duration in the resin's instructions and, if in doubt, choose a more durable resin. Longevity also depends on the thickness of the restoration, the number of bridge units, the patient's occlusion and bruxism.

Design tips

The SHINING 3D application guide for CB11 and TN11 specifies:

• Cement gap – 0.03–0.05 mm (a slightly larger gap is allowed to accommodate excess cement);
• minimum thickness – about 1 mm, more than 0.5 mm on the buccal surface.

General principles that apply to all temporary resins:

• Provide a sufficient cross-section for bridge connectors – the connector is the weakest point, especially in longer bridges.
• Respect the maximum number of bridge units specified by the resin manufacturer.
• Plan occlusal contacts at the CAD stage – this means less grinding and no damage to the surface.
• If the temporary is a prototype of the final restoration, save the approved file – its shape will become the basis for the final restoration.

Print orientation and supports

The SHINING 3D guide recommends that, for CB11 and TN11 resins, the occlusal surface faces the platform and no supports are placed on the intaglio (fitting) surface. This protects the marginal fit, and the support marks remain in places that are easy to grind away. For these resins, the manufacturer suggests a small resin tank and a small ceramic platform – convenient when only a few units are printed.

Both lab and chairside printers are suitable for temporary restorations: the AccuFab-L4D / L4K with the CreTemp module in the AccuWare software, the compact AccuFab-Aris for clinics, or the HeyGears UltraCraft A2D-HD for HeyGears resins. We discussed the criteria for choosing a printer in a separate knowledge base article.

Washing and post-curing

Temporary restorations are small but have precise margins, so they must be washed carefully. The SHINING 3D guide for CB11 and TN11 specifies:

1. Ultrasonic washing in isopropanol (≥ 75%) for about 2 min, then a second time in clean isopropanol; or in the FabWash station with the "CB" setting.
2. Drying with compressed air and a 5 min rest.
3. Post-curing in the FabCure N2 unit – 10 min at 50 °C.

Please note: the TN11 product description specifies washing with 95% ethanol (20 s by hand and 60 s in an ultrasonic bath), so check the latest instructions for use of the resin before establishing the protocol in your lab. For HeyGears resins, washing and curing are automated by the UltraCraft Wash and UltraCraft AirCure. According to the manufacturer, curing in a nitrogen atmosphere, for example in the Graphy Tera Harz Cure N2, eliminates the tacky surface layer. More in Washing and curing 3D prints.

Polishing, characterization and cementation

Supports are removed after curing, and the support points are smoothed with silicone polishers – the SHINING 3D guide for CB11 specifies a silicone bur of about 150 µm at 15,000–30,000 rpm. Polishing then continues in the usual sequence to a high shine or, as SHINING 3D suggests, a thin layer of glaze is applied and briefly cured in the FabCure N2 in aesthetic mode (30 s in a nitrogen atmosphere).

For characterization, use only the staining and glazing materials permitted by the resin manufacturer. Do not polish the margins or the intaglio surface – this alters the fit.

Temporary restorations are usually cemented with temporary cement. We wrote about choosing a temporary resin cement in the article U-Cem Premium or Care Cem Temp, and you will find the temporary resin cement Vericom Care Cem Temp in our online store. Before cementing, make sure the chosen cement is compatible with resin restorations, and remove the excess before it sets – the surface of a resin temporary restoration is more sensitive to sharp instruments than ceramic.

The most common mistakes

• A temporary resin is used for too long. If treatment has been prolonged, replace the temporary or choose a more durable resin in advance.
• Connectors that are too thin. The bridge connector is the first place where the restoration fractures, so do not skimp on its cross-section.
• Insufficient washing. Residual resin on the intaglio surface prevents the restoration from seating and impairs surface quality.
• Curing in "any" unit. The curing mode must match the resin – otherwise the resin does not achieve its declared properties.
• Support marks on the margins. Grinding them away compromises the marginal fit – plan supports in non-fitting areas.

Frequently asked questions

What is the difference between CB11 and CB12?

CB11 is a basic resin for temporary crowns, bridges and denture teeth, available in 7 shades. CB12 is reinforced with a ceramic filler and, according to the manufacturer, has higher flexural strength and lower water absorption, so it is intended for longer temporary or semi-permanent use.

Can a temporary be printed with a permanent restoration resin?

Yes – a resin intended for permanent restorations, such as CB200, is also suitable for a temporary period. However, it is often more sensible to choose a resin suited to the indication: CB11 or HeyGears Temp For Try-in UV for a short period, CB12 for a longer one.

Why does the printed crown not seat?

The most common causes are a cement gap that is too small, supports on the intaglio surface, insufficiently washed resin or incorrect orientation. Start with the design parameters and support placement.

Is post-curing mandatory?

Yes. The manufacturers of all the resins mentioned state that post-curing is mandatory after printing – without it, the resin does not achieve its declared mechanical properties and biocompatibility.

Which resin should I choose for an All-on-X temporary restoration?

SHINING DENT CX100 and HeyGears On-X Teeth Try-in UV are intended for full-arch implant restorations and, according to the manufacturers, offer high fracture resistance. For such cases, accurate scanning of implant positions is particularly important – you will find a separate article on this in our knowledge base.

Summary

Printed temporary crowns and bridges save time and make it possible to check the shape of the future restoration, but the resin must be chosen according to the planned wearing time, and design, orientation and post-processing must follow the manufacturer's instructions. You will find all crown and bridge resins in the Resins section. Would you like advice on a resin or equipment? Contact IMMT or call +370 601 00030.