Instructions for Use (IFU) for printing aligners with DLP & LCD printers

This document provides application-specific technical guidance for the printing of orthodontic aligner components using 3Dresyns® photopolymer resin systems on DLP and LCD vat photopolymerization printers.

This document does not replace the general IFU documents and applies only to orthodontic-related additive manufacturing workflows.

Important: 3Dresyns resin systems are supplied as professional manufacturing materials for additive manufacturing. They are not placed on the market as finished medical devices, certified medical components, or CE-marked accessories. Any medical device manufactured using these materials remains under the full regulatory responsibility of its legal manufacturer.

This IFU is part of the structured documentation system described in the Medical & Biocompatible 3D Printing Framework, where performance, safety and biocompatibility are defined at system level.

Scope of application

This IFU applies to:

• printing of orthodontic aligner components and thermoforming molds
• DLP and LCD vat photopolymerization systems
• 3Dresyns resin systems used within orthodontic manufacturing workflows

This IFU does not apply to:

• non-orthodontic dental devices
• laser-based SLA systems unless specifically validated
• off-label or unvalidated clinical workflows

Nature of aligner printing workflows

Orthodontic aligner production is a highly application-sensitive and multivariable manufacturing process.

Final part performance depends on the interaction between:

• resin formulation and version
• printer technology and exposure strategy
• printing orientation and layer thickness
• post-processing and post-curing workflow
• thermoforming conditions

Printed parts must therefore be considered process-dependent manufactured components, whose performance is determined by the complete material–printer–process system, not by intrinsic resin properties alone.

Residual species and thermoforming considerations

Photopolymer conversion is not absolute. Residual unreacted species, additives, photo accelerant residues and reaction by-products may remain within printed parts depending on formulation, exposure conditions and post-processing efficiency.

During thermoforming, printed molds are exposed to:

• elevated temperatures
• mechanical pressure
• polymer sheet contact

These conditions may increase mobility of residual species or alter surface chemistry if polymer conversion and post-processing are not properly controlled.

• resin formulation and raw material selection
• degree of polymer conversion
• post-curing efficiency (light and/or thermal)
• cleaning and drying effectiveness
• geometry and thickness of printed molds

Important: Materials containing reactive or hazardous components prior to curing may retain residual fractions after processing. These residuals may remain trapped within the printed structure and may influence performance under thermoforming conditions.

Monomer Free (MF) resin systems are designed to reduce the presence of reactive residual species at the formulation level, contributing to improved process stability and reduced extractable-related risks when processed under validated conditions.

Printer and exposure considerations (DLP & LCD)

DLP and LCD printers expose entire layers simultaneously. As a result:

• exposure time strongly influences dimensional accuracy
• overcuring may affect surface fidelity and fit
• undercuring may reduce mechanical stability and durability

Layer thickness, exposure time and light intensity must be optimized and validated for each printer–resin combination.

Orientation and support strategy

Aligner components or molds should be oriented to:

• minimize internal stresses
• reduce layer stepping on functional surfaces
• ensure uniform curing

Support structures must avoid contact with critical fitting areas whenever possible. Support removal and surface finishing may influence final dimensional accuracy.

Calibration and validation

Prior to production, users must:

• calibrate exposure parameters for the selected resin and printer
• validate dimensional accuracy using reference geometries
• confirm reproducibility across multiple builds

Internal quality controls and documented validation protocols should be implemented to ensure consistency.

Post-processing and post-curing

Post-processing is a critical manufacturing step.

Washing, drying and post-curing conditions directly influence:

• mechanical behavior
• surface chemistry
• residual species content
• long-term stability

Post-processing must strictly follow the qualified workflows defined in the applicable IFU. Deviations may significantly alter performance characteristics.

Biocompatibility and safety considerations

Where materials are positioned for biocompatibility-oriented workflows, users are responsible for:

• selecting appropriate resin versions
• following the IFU for biocompatible resins
• validating cleaning and post-curing effectiveness
• ensuring that residual reactive substances are adequately reduced

Biocompatibility performance depends on validated processing conditions. The final medical device manufacturer remains solely responsible for device qualification, risk assessment and regulatory compliance under applicable regulations, including Regulation (EU) 2017/745 where applicable.

Quality control and reproducibility

Users should implement internal quality controls including:

• dimensional checks
• visual inspection
• batch traceability
• documented process validation

Controlled and documented workflows are essential to ensure reproducibility.

Limitations and responsibilities

This IFU provides application-specific technical guidance only.

Users are responsible for:

• validating part performance within their manufacturing environment
• ensuring regulatory compliance of any finished medical device
• conducting appropriate risk assessment and conformity evaluation

3Dresyns does not assume responsibility for clinical outcomes, device certification, CE marking, or regulatory approval of final products manufactured using its materials.

Relationship to other Instructions for Use

This IFU must always be used together with:

• Instructions for Use (IFU) & Printing Parameters for DLP & LCD printers
• Instructions for Use (IFU) for Biocompatible Resins
• Instructions for Use (IFU) for Ultra Gloss and Transparency
• any printer-specific IFU relevant to the selected equipment

In case of discrepancy, the most application-specific IFU prevails.

Governing principle