PDF: Maximizing Durability of CAD/CAM Resin-Based Ceramics: Milled vs. 3D-Printed Ultra-Thin Occlusal Veneers and Luting Strategies

Addressing the growing issue of pathological tooth wear, this in vitro study explores the potential of ultra-thin occlusal veneers as a more conservative restorative alternative to full-coverage crowns, inlays, or onlays.

To evaluate how fabrication methods (milled vs. 3D-printed resin‑based ceramics) and varying luting (cementation) strategies affect the fracture resistance of these ultra-thin veneers after thermomechanical cyclic loading.

Materials & Methods

★ Specimens: 60 ultra‑thin veneers were fabricated (thickness 0.8 mm) and divided equally into two material groups: milled (Cerasmart®, GC Corp.) and 3D‑printed (VarseoSmile Crown plus A3, BEGO).

★ Each group was subdivided into three subgroups (n = 10) according to the luting method:

1. Adhesive resin cement (RC – RelyX Ultimate).

2. Bulk-fill flowable composite (BF – Surefil SDR flow).

3. Preheated bulk-fill nano‑hybrid resin composite (PN – Tetric EvoCeram).

★ All specimens were cemented onto anatomical 3D‑printed resin dies and subjected to thermomechanical load cycling, followed by fracture resistance testing using a universal testing machine.

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Results

★ Fracture resistance was significantly influenced by both the fabrication method and the luting approach (p  0.001).

★ Milled veneers demonstrated significantly higher fracture resistance than their 3D‑printed counterparts (P = 0.001).

★ Within the milled group, veneers cemented with PN outperformed those with RC (P = 0.009), while in the 3D‑printed group, PN also provided better results than RC (P = 0.008).

★ Overall, the highest strength was achieved with milled veneers cemented using PN; the lowest, with 3D‑printed veneers using BF.

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Conclusions

The type of resin cement notably influences fracture resistance in both milled and 3D‑printed resin‑based ceramic veneers.

The combination of milled veneers with preheated nano‑hybrid resin composite (PN) yielded the greatest fracture resistance, suggesting optimal longevity in clinical applications.

These ultra‑thin veneers represent a minimally invasive restorative option for reducing further tooth wear and avoiding full coverage crown preparations.

★ I warmly invite you to dive deeper into this compelling work—available in full via PDF on the BMC Oral Health site. It offers valuable insights into optimizing fracture resistance in ultra-thin occlusal veneers using current CAD/CAM and luting technologies.