Advances in Dental Restorations: A Comprehensive Review of Machinable and 3D-Printed Ceramic-Reinforced Composites.

Objective: This review aims to evaluate the current understanding and clinical applications of machinable ceramic-reinforced composites (CRCs) and the emerging first generation of 3D-printed CRCs in dental restorations.

Overview: Machinable CRCs, introduced over a decade ago, have shown moderate success in short- to medium-term clinical applications, particularly in low-stress areas. However, their long-term durability limitations, such as increased wear and marginal deterioration, restrict their use in high-stress situations and full crowns. The first generation of 3D-printed CRCs offers customization advantages but is still in early development and exhibits lower mechanical strength and higher wear rates than CAD-CAM CRCs and traditional ceramics. Additionally, the classification and definitions surrounding CRCs remain ambiguous, as ADA categorizations do not clearly differentiate CRCs from ceramics, complicating clinical indication, usage, and billing practices.

Conclusion: Machinable CAD-CAM CRCs are moderately successful in low-stress applications, while 3D-printed CRCs show limitations in wear resistance and durability, raising concerns for their use in definitive restorations. Both require further research and clinical validation.

Clinical Significance: Machinable CAD-CAM CRCs are best suited for low-stress applications, while 3D-printed CRCs may be more appropriate for provisional use. Until long-term clinical data are available, ceramics should be preferred for high-stress or full-coverage restorations. Clearer definitions for porcelain/ceramic and comprehensive application guidelines are urgently needed to support clinician decision-making and improve patient outcomes.