07 September 2023

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Efficiency of 3D-printed composite resin, CAD/CAM materials

By Lorenzo Breschi and Carlo D’Alessandro

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Introduction

Three-dimensional (3D) printing, an additive manufacturing based on computer-aided design (CAD) technologies, has entered the dental market as one of the most innovative technologies. Since then, its use has entered the daily clinical practice of several dental specialties, allowing the fabrication of working models, surgical guides, occlusal splints, removable partial or full dentures, temporary crowns and bridges.

By incorporating ceramic fillers into the polymer resin printing material, improvements have been made in terms of esthetics, durability and biocompatibility. More recently, 3D-printed composite resins have been introduced as viable materials for definitive restorations, including crowns, bridges, veneers, inlays and onlays. However, limited information is available regarding the adhesive interface stability and overall efficiency of these new 3D-printed materials.

In this regard, Daher et al. have conducted a laboratory study to compare the marginal integrity of the adhesive interface before and after thermo-mechanical fatigue between a 3D-printed composite resin and subtractive CAD-CAM materials. The study also sought to evaluate the cost and time efficiency of production for these materials.

Materials and methods

Freshly extracted sound molars were selected for the study and prepared for standardized onlays. Four different materials were used for restorative purposes: 3D-printed composite resin (VarseoSmile Crown Plus), milled composite resin (Tetric CAD), milled PMMA (Telio CAD) and milled lithium disilicate (IPS e.max CAD). Marginal analysis was assessed under a scanning electron microscope before and after subjecting the indirect restorations to fatigue through thermomechanical cyclic loading. The initial and final percentages of continuous margin (%CM) were compared among groups. Additionally, the time required for fabricating each type of restoration was recorded, and a comparative analysis of production costs was conducted.

Results

Before fatigue, there were no statistically significant differences in %CM values between 3D-printed composite, milled composite and lithium disilicate groups (69.8%, 75.9%, and 63.1%, respectively), while milled PMMA exhibited significantly lower results (45.1%) among groups.

After aging, comparable results were shown by 3D-printed and lithium disilicate (44.7% and 43.7%, respectively), which were lower than the milled composite (68.5%), but higher than milled PMMA (20.5%). Moreover, 3D printing demonstrated greater time efficiency compared to both milled composite and PMMA, when fabricating more than 8 restorations. In terms of the cost-efficient production, 3D printing was found to be 5.5, 8.7, and 10.2 times less expensive than PMMA, milled composite and lithium disilicate, respectively. The initial equipment investment cost for the additive manufacturing method was also lower.

Conclusion

Within the limitations of this laboratory study, the authors concluded that long-term indirect restorations may be successfully fabricated using 3D-printed composite resins, offering advantages in terms of consumable cost and production time. The tested 3D-printed material exhibited a better quality of the marginal adaptation compared to milled PMMA and similar performance to lithium disilicate, both before and after thermomechanical cyclic fatigue.

René Daher et al. "Efficiency of 3D-printed composite resin restorations compared with subtractive materials: Evaluation of fatigue behavior, cost, and time of production." J Prosthet Dent. 1 November 2022. https://doi.org/10.1016/j.prosdent.2022.08.001.