Polishing of 3D-printed restorations: How to achieve a durable shine and hygienic surfaces

3D printing has become an established manufacturing technology in dentistry. Whether in a dental laboratory or a dental office, modern 3D printing materials enable cost-effective production of crowns, splints, or provisional restorations. However, even in a digital workflow, a classic step remains decisive: polishing the surface.

3D-printed restorations exhibit characteristic layer structures and slight surface roughness. Only specific surface finishing makes it possible to smooth these structures and achieve a surface quality that is both functional and esthetic.

Whether resin or filament: A print is ready only when the surface meets the requirements.

Besides resin-based printing technologies, filament printers are gaining importance. One example is SIMPLEX 2 SX, a dental filament printing system for dental offices and laboratories—for example, for 3D printed temporary restorations.

As a result, a very practical question comes into focus in everyday laboratory work:
Which polishing paste is suitable for polishing 3D-printed restorations?

The polishing targets for 3D-printed restorations are the same as for milled restorations, however, with material- and process-specific characteristics. Appropriate polishing primarily meets two key objectives.

Reducing surface roughness

Smoothed surfaces prevent staining. Printed polymers and resins, in particular, exhibit a significantly higher tendency toward color instability when their surfaces are rough. Moreover, surface quality plays an important role with regard to the hygiene and biocompatibility of a restoration. Rough surfaces promote the accumulation of plaque and microbial biofilms. Careful polishing helps prevent these build-ups and contributes to maintaining stable and hygienic surfaces in the oral cavity over the long term.

Improvement of aesthetics

A smooth surface provides stable luster and natural light reflection. It is important to distinguish between short-term optical gloss and true surface polishing. An optical sheen can also be created by oils, for example. However, only professional polishing truly reduces surface roughness and ensures a lasting, long-term high gloss finish.

These aspects are relevant for both temporary and definitive 3D-printed restorations, such as crowns, inlays, onlays, veneers, or prosthetic components.

The Renfert Polish family follows a clear concept: specific polishing pastes for different materials.  The philosophy is simple: one system for everything—but not “one size fits none.” Instead of a universal solution, Renfert relies on clearly separated product lines:

With the new paste „Renfert Polish – 3D-printed materials“ the systematic approach is expanded to include 3D-printed materials.

Color coding for quick orientation

To simplify application in daily lab routine, the polishing pastes are color-coded. This enables quick assignment of the correct paste to the corresponding material and supports a reliable workflow.  Especially in dental laboratories where a wide range of materials is processed, color coding makes it easier to reach for the appropriate paste and helps avoid mix-ups. The Renfert Polish 3D-printed materials polishing paste comes in a neutral beige-gray color.

The diamond polishing paste Renfert Polish 3D-printed materials was developed for polymer-based materials from the 3D printer. Typical applications include, for example:

• Crowns or inlays made of filament or resin
• Temporary restorations (e.g. SIMPLEX filaments temp)

The paste removes or smooths typical printing artifacts such as:

• layer lines
• support remnants
• transitions between printed layers

The goal is not just high-quality polishing, but a well-defined workflow for 3D-printed surface finishing.

The focus is on structured steps that

• reduce processing time,
• ensure long-term stable surface luster,
• enable hygiene-friendly surfaces,
• and standardize the digital workflow. 

Another advantage of the paste is its versatility across different technologies. Renfert Polish 3D-printed materials can be used both for filament-printed restorations made of PMMA and PETG, as well as for crown and bridge restorations made of resin.

Polishing in 3D printing – how it works: Renfert Polish 3D printed materials starter kit

In addition to the paste, Renfert offers the Renfert Polish 3D printed materials starter kit. This is a 4-step polishing system for use on printed objects.

Step 1 – Prepolishing

In the first step, typical printing structures such as layer lines or support remnants are removed. Two different pre-polishers are available for this purpose.

Prepolisher side (e.g., for the vestibular or buccal surfaces of a crown)

• Hard felt polisher
• ideal for larger, flat surfaces
• smooths layer lines and print artifacts
• removes minor support remnants

Prepolisher top (e.g., for occlusal surfaces)

• Silicone lamellar polisher
• flexible lamellar structure
• reaches even deeply recessed structures such as grooves or occlusal surfaces without completely reducing their occlusal structure
• removes minor support remnants

Step 2 – Polishing

In the second step, polishing is carried out using a goat hair brush in combination with the diamond polishing paste Renfert Polish 3D-printed materials The fine natural hairs distribute the polishing paste evenly and adapt flexibly to the surface.

Step 3 – Luster polishing

For a mirror-like finish, luster polishing is performed using a leather buff made of high-quality special leather. It uniformly densifies the surface and ensures homogeneous light reflection.

Step 4 – High-gloss polishing

Final polishing is carried out using a special cotton buff. Cotton fibers dissipate heat better than synthetic microfibers, thereby reducing the risk of deformation in polymer-based materials. Optionally, polishing paste can be used again for this step. Cotton fibers have high capillarity and bind the polishing paste particularly evenly.

After pre-polishing, esthetic customization with stains can be carried out as needed—for example, to depict fissures, translucencies, or cervical nuances on printed crowns. Pre-polishing creates an ideal surface. It reduces print artifacts and provides a uniform base for the stains.

3D printing is changing how dental restorations are manufactured, but it does not change the requirements for their surfaces. With Renfert Polish 3D-printed materials and the associated starter kit, Renfert is expanding its polishing system with a clear, systematic approach for polishing printed restorations.