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Typical Issues in Dental UV 3D Printing (Part 2)

Release time:

2026-08-13 17:03

Typical Issues in Dental UV 3D Printing (Part 2)

After completion, dental UV‑cured 3D‑printed models must undergo a cleaning process to remove uncured liquid resin adhering to the surface. However, many printed parts exhibit a whitish surface after cleaning, compromising both their aesthetic appeal and clinical usability. The root cause of this issue lies in inadequate cleaning procedures—any oversight, from the selection of cleaning solvents to the standardization of the cleaning workflow, can lead to surface defects.

1. Improper alcohol concentration results in incomplete cleaning.

The concentration of the cleaning alcohol directly affects the cleaning performance. If the alcohol concentration falls below the specified standard, its ability to dissolve uncured resin will be insufficient, failing to effectively remove liquid resin adhering to the model’s surface. Residual resin can subsequently form white spots or a whitish layer during the curing process, compromising the model’s transparency and surface smoothness.

Some operators, in an effort to cut costs, use diluted alcohol for cleaning, a practice that often compromises cleaning performance. It is essential to use alcohol at the prescribed concentration as specified in the material’s instructions and to replace the cleaning solution regularly.

II. Secondary Contamination Caused by Saturated Cleaning Solution

Repeatedly using the same bottle of alcohol to clean multiple printed parts causes the concentration of uncured resin in the cleaning solution to gradually increase. Once the solution reaches saturation, the alcohol’s dissolving power declines significantly; rather than removing residual resin from the part’s surface, it may even redeposit resin dissolved in the alcohol back onto the model’s surface.

This type of secondary contamination, once cured, can manifest as white‑foggy or spotted surface defects that are difficult to remove through subsequent processing. It is recommended to replace the cleaning solution regularly to prevent incomplete cleaning caused by alcohol saturation.

III. Curing Defects Caused by Insufficient Drying

After cleaning, any residual alcohol on the model’s surface must be allowed to evaporate completely before curing. If secondary curing is performed before the alcohol has fully dried, the remaining alcohol may react with the resin during the curing process or form bubbles, resulting in a whitish surface or the appearance of tiny pits.

Some operators, in an effort to expedite the process, wipe the surface with paper towels or dry it with a hair dryer; however, these methods may introduce new contaminants or damage delicate structures. It is recommended to allow the cleaned model to air‑dry in a clean environment, ensuring that all alcohol has fully evaporated before proceeding to the curing stage.

IV. Surface tackiness caused by insufficient secondary curing time

Secondary curing (post‑curing) is a critical step for ensuring complete resin polymerization. If the post‑curing time is insufficient, the resin on the model’s surface will not fully crosslink, and residual unreacted monomers can leave the surface tacky. Such a sticky surface readily attracts dust and may lead to discoloration or white spots during subsequent use.

Research indicates that extending the post‑curing time can enhance the surface cure of printed parts; however, excessive curing may render the material brittle. The optimal curing duration should be determined based on the material type and the settings of the post‑curing equipment.

V. Conclusion

The whitening issue on the surfaces of dental UV‑3D prints primarily stems from improper cleaning procedures. Insufficient alcohol concentration fails to effectively remove uncured resin; saturation of the cleaning solution leads to secondary contamination; inadequate air‑drying allows residual alcohol to create defects during curing; and insufficient post‑curing time results in surface tackiness and white‑spot residues. To address these problems, use alcohol of the specified concentration, replace the cleaning solution regularly, ensure thorough drying of the model, and set an appropriate post‑curing duration. A standardized cleaning protocol is essential for maintaining the surface quality of printed parts.

Disclaimer: The above content has been compiled from publicly available sources and is provided for reference only. If any infringement occurs, please contact us, and we will address it promptly.

Bossin Related Product Recommendations – 3D Printing
Dentistry
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-100M	Bisphenol A epoxy acrylate	Low viscosity, high hardness, high gloss, and high body.
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, contains 20% TPGDA.
B-276H	Aliphatic polyurethane acrylate	High hardness, fast curing, excellent toughness, and low yellowing.
B-296	Aliphatic polyurethane acrylate	Fast curing, chemical resistance, yellowing resistance, impact resistance
B-296M	Polyurethane acrylate	Fast curing, resistant to polar solvents, yellowing-resistant, and impact-resistant.
B-301	Aromatic polyurethane acrylate	Fast curing, excellent toughness, and good sandability.
B-302	Aromatic polyurethane acrylate	Fast curing, high strength, excellent toughness, and good grindability.
B-368	Aliphatic polyurethane acrylate	Good toughness, excellent leveling, excellent bend resistance, and excellent heat resistance.
B-376	Aliphatic polyurethane acrylate	LED yellowing is minimal, and the nail polish formulation exhibits excellent stability.
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, and chemical resistance.
B-79D	Polyester acrylate	High hardness, low yellowing, and high evaporation efficiency at elevated temperatures.
Monomer Recommendation
Product Model/English Abbreviation	Product Name/Product Type	Product Features
BM1211 (HPMA)	Hydroxypropyl methacrylate	HEMA-free, high strength, low irritation, and excellent adhesion
BM2223 (TPGDA)	Dipropylene glycol diacrylate	Good flexibility and low volatility
BM3231 (TMPTA)	Trimethylolpropane triacrylate	High crosslink density, high hardness, high gloss, and excellent wear resistance.
BM3235 (PET3A)	Pentaerythritol triacrylate	Fast curing, high crosslink density, high hardness, and chemical resistance.
BM3380 (3EO-TMPTA)	Pentaerythritol triacrylate	More flexible and less irritating than TMPTA.

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Typical Issues in Dental UV 3D Printing (Part 3)

Typical Issues in Dental UV 3D Printing (Part 1)