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Troubles Occurring in Post-Processing of 3D Models in Aligner Production
Clear aligners have become one of the most in-demand orthodontic appliances in recent years. Patients are excited about their near-invisible appearance and improved comfort over traditional braces. As the popularity of aligner treatment continues to rise, dental clinics are looking for ways to meet this growing demand while keeping costs manageable—both for themselves and for their patients. This has led many clinics to explore the possibility of in-office aligner production.
The typical aligner manufacturing workflow includes three key components: an input device (intraoral scanner), software for digital treatment planning, and an output device (3D printer). However, there's a significant hurdle: most CAD software doesn't generate 3D models that are fully ready for printing. These files often require additional digital processing before they can be used in production.
In this article, we’ll explore the key challenges that arise during the post-processing phase.
Common Challenges in Post-Processing of 3D Models
Post-processing is a critical—yet regularly overlooked—step in the digital workflow of clear aligner production. The quality of post-processing directly affects not only how well the aligners will fit the patient's teeth, but also how smoothly and efficiently they can be manufactured. Even the most accurate treatment plan can lead to suboptimal results if the 3D model is not properly prepared for printing.
One of the biggest challenges clinics and labs face is that most traditional CAD software, such as Maestro 3D or OnyxCeph, does not generate 3D models that are fully optimized for manufacturing. The exported models often lack essential details and require significant manual edits before they can move into production.
Technicians typically need to perform additional adjustments. These manual interventions can significantly slow down the workflow and introduce variability in production quality. In high-volume or automated environments, this lack of readiness becomes a serious problem.
Labeling and Model Identification
In traditional workflows, it’s common to emboss simple text labels—such as the Case ID, patient name, or stage number—directly onto the digital 3D model. While this may suffice for manual handling in small labs, it quickly becomes inadequate in an industrial environment.
To enable seamless tracking and integration with production management systems, a more advanced approach is needed: machine-readable 3D codes—or Data Matrix codes. These function like QR codes and can be recognized by computer vision systems at every stage of production—from printing and post-curing to trimming and packaging.
Incorporating Data Matrix codes directly into the digital model allows clinics and labs to automate identification, reduce errors, and scale operations more efficiently. Without this step, traceability becomes harder to maintain as production volumes grow.
Fixtures for Automated Trimming
When clear aligners are trimmed using automated cutting machines, the model must be compatible with that equipment. This means adding a digital fixture—a mounting base designed to fit the specific type of trimming device used in the lab.
This fixture isn’t an external part, so it must be embedded directly into the model’s geometry during the digital planning stage. Without it, technicians may need to manually position or adjust each model, negating the benefits of automation and increasing production time. Not every dental CAD software supports digital fixtures, making it difficult for clinics and labs to implement true automation.
Undercuts and Bridges in Edentulous Areas
When a patient is missing one or more teeth, the absence of anatomical support can create significant challenges in aligner production. During thermoforming, aligner material may collapse or deform into the open spaces, compromising the fit and function of the appliance.
To address this, digital bridges (also called pontics) must be added to the model. These structures simulate the missing tooth and help maintain the correct form and thickness of the aligner in that region.
However, not all CAD systems can handle this task correctly. In many workflows, technicians have to manually edit each 3D model or perform physical wax-ups—a time-consuming and inconsistent process. Without the pontics, the final aligner may be uncomfortable for the patient or fail to provide the intended force transmission.
Undercuts between Crowded Teeth
In cases of crowding and narrow gaps between teeth—often referred to as black triangles—can lead to complications during aligner production. These small undercuts may cause the plastic material to flow too deeply into interproximal spaces during thermoforming.
As a result, the aligner may become overly retentive, making it difficult for the patient to insert or remove it without discomfort. In some cases, excessive retention can even lead to damage or distortion of the aligner.
In many small labs, this issue is still handled manually by filling in undercuts with wax before forming. While this approach can be effective, it’s time-consuming and inconsistent, especially at scale. A more reliable and efficient solution is to address these undercuts digitally during post-processing.
Digital Solutions for Better Post-Processing
As discussed, post-processing is a critical step that directly affects aligner fit, production efficiency, and scalability. Traditional CAD software often lacks essential tools for industrial-level automation, which forces technicians to manually modify models. This not only slows down production but also introduces the risk of human error and inconsistent results.
For clinics and labs planning to scale in-office aligner production, it’s crucial to choose software that not only designs aligners but also prepares fully manufacturable 3D models.
eXceed Features
eXceed is a web-based platform built for clear aligner design and treatment planning. Its workflow is simple and intuitive:
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Doctors upload patient data, including 3D intraoral scans, photos, and X-rays
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Trained technicians design a full set of staged models, each representing a treatment step
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Doctors review the digital setup, request modifications if needed, and approve the final plan
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Once approved, fully printable 3D models are delivered—ready for in-office production
What sets eXceed apart from many other aligner providers is flexibility. Doctors retain full control over manufacturing: they receive the digital files but are not obligated to order physical aligners from eXceed. This opens the door for cost-effective, in-office aligner production, significantly lowering treatment costs for patients.
Post-Processing Advantages of eXceed
eXceed addresses the major problems of traditional software with a suite of automated tools designed for real-world manufacturing:
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Embeds Data Matrix codes for machine-readable identification
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Integrates trimming fixtures into each model for seamless use with automated equipment
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Adds digital bridges to edentulous areas for optimal material shaping
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Fills undercuts and black triangles to avoid tight-locking aligners
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Delivers ready-to-print models with no need for manual post-processing
Conclusion
Traditional CAD workflows often fall short when it comes to preparing aligner models for production, creating troubles that slow down manufacturing and increase the risk of human error. As clinics and labs look to scale up and offer in-office aligner solutions, automated post-processing becomes a critical component of successful and efficient production.
Digital tools that embed labeling, fixtures, and model corrections directly into the workflow—like those offered by eXceed—are no longer just convenient; they are essential for delivering consistent, high-quality results in a scalable way.
