1. Technological Background
The introduction of digital workflows has fundamentally changed the production of dental restorations. CAD models created from intraoral or model scans enable precise design, while modern 5-axis milling machines can reproducibly manufacture even complex geometries. Material selection is closely tied to technological capabilities, as different materials impose different demands on the milling process.
Ceramic materials such as zirconia and lithium disilicate are among the most commonly used today. They are known for high stability and excellent aesthetic properties. Zirconia was originally used mainly for its high flexural strength; however, newer developments increasingly allow for translucent variants with improved light transmission. According to Sulaiman (2020), the trend clearly points toward highly translucent ceramics offering optics similar to e.max.
A second category includes polymer-based materials and hybrid ceramics. These offer better millability due to softer structures and reduced tool wear. Eskandarion (2021) highlights that this material class is particularly relevant for chairside applications because of fast production cycles.
Technological progress is also increasing the relevance of metallic materials in the digital milling process. Titanium and CoCr alloys have traditionally been processed through sintering, but milling technology provides higher precision and improved surface quality. Research by Ruggiero et al. (2025) shows that metallic materials continue to play a key role in laboratories and industrial centers due to their mechanical stability.
At the same time, new material types such as 3D-printed zirconia are emerging. Su et al. (2023) argue that additively manufactured zirconia may become a promising alternative to traditional milling in the future — although its mechanical properties are not yet fully comparable.
2. Practical Application / Use Cases
Zirconia: The Universal Material
Zirconia is considered the standard for crowns and bridges, especially in the posterior region, due to its high mechanical strength. Its applications range from monolithic restorations to frameworks for veneered ceramics. Modern, highly translucent generations also allow aesthetic anterior solutions. A systematic review by Małysa et al. (2025) confirms its high biocompatibility and broad clinical evidence.
Lithium Disilicate: Aesthetics for Anterior Restorations
Lithium disilicate offers exceptional optical properties and good millability. It is ideal for inlays, onlays, veneers, and single-unit crowns. Due to its glass-like structure, it can be manufactured with minimal thickness, allowing minimally invasive preparations. However, its flexural strength is lower than zirconia, making it less suitable for larger bridges.
Hybrid Ceramics and Composite Blocks
Hybrid materials combine polymer matrices with ceramic fillers. They are easy to mill, cause less tool wear, and offer elastic properties beneficial under occlusal stress. Eskandarion (2021) notes that these materials are ideal for chairside workflows since they do not require crystallization firing.
PMMA and Long-Term Provisionals
PMMA is now used not only for short-term temporaries but increasingly for long-term provisionals with high material homogeneity. Industrially polymerized PMMA disks offer improved fracture resistance and aesthetic stability. They are indispensable for temporary bridges, test phases in complex prosthetics, and diagnostic models.
Metals: Titanium and CoCr
Milled titanium is standard today for implant abutments and bar structures due to its biocompatibility and strength. CoCr alloys are widely used for bridge frameworks and metal-ceramic restorations. Ruggiero et al. (2025) show that modern milling technology processes metallic materials with high precision, reducing error rates.
New Materials: Additive Technologies
Su et al. (2023) report that 3D-printed zirconia is an emerging innovation. Its additively produced microstructures may reduce wear over time. However, its clinical use is still in early stages.
3. Benefits for Manufacturing Centers
Dental Laboratories
Material selection is closely tied to productivity, aesthetics, and process reliability. Milling-optimized materials shorten production times and reduce tool costs. PMMA and hybrid ceramics allow fast processing, while zirconia and lithium disilicate enable high-quality definitive restorations. Małysa et al. (2025) support this distinction between temporary and definitive material classes.
Milling Centers
Milling centers often work with a broad material portfolio to serve external clients. Materials influence production capacity, tool lifespan, and machine utilization. High-strength zirconia or titanium require powerful machines but offer high margins and broad indications. Ruggiero et al. (2025) emphasize the role of milling-optimized metals in maintaining process stability.
4. Challenges / Limitations
Material selection also brings challenges. Zirconia can develop internal tension if not sintered correctly or if poorly designed. Lithium disilicate is fracture-prone under heavy occlusal load. Hybrid ceramics may lack long-term stability compared to traditional ceramics. Biocompatibility is another crucial factor: Małysa et al. (2025) highlight that variations in material composition significantly influence tissue response.
Tool wear is another issue. Hard materials like zirconia require diamond tools and optimized spindle speeds. Inadequate process management may lead to quality issues or microfractures.
5. Market & Future Perspectives
Material development is advancing rapidly. Trends include translucent zirconia, new hybrid materials combining strength and aesthetics, and additive manufacturing. According to Su et al. (2023), additive ceramic manufacturing will gain significance, particularly for personalized zirconia structures.
Sustainability is becoming more important as well — energy-efficient milling and recyclable materials are increasingly discussed. New polymer materials may become economically attractive due to fast milling and low tool wear.
6. Conclusion & Recommendations
Material selection is a strategic factor for dental laboratories and milling centers. Zirconia remains the standard for definitive restorations, while hybrid ceramics and PMMA are gaining importance for temporary and chairside workflows. Lithium disilicate is essential for aesthetics, and metals remain important for implant-supported prosthetics.
Labs should design their material portfolio to meet both aesthetic and economic needs flexibly. Milling centers benefit from a broad material base covering wide indications. Based on the literature cited, investments in modern materials improve process reliability and reduce costs long-term.
FAQ:
Which material is best suited for monolithic crowns?
Zirconia is currently considered the preferred material for monolithic crowns because it offers high flexural strength and good long-term properties. Modern translucent variants also enable aesthetic design in the anterior region. Lithium disilicate offers better aesthetics, but is less suitable for higher loads. Laboratories should decide based on the indication.
What are the advantages of using hybrid ceramics for chairside restorations?
Hybrid ceramics can be milled quickly and efficiently because they have a lower hardness than classic ceramics. They do not require crystallization firing, which significantly reduces production time. They also have elastic properties that can be advantageous for occlusal loads. However, ceramics are preferable for long-lasting definitive restorations.
Are PMMA long-term temporary restorations clinically safe?
Industrially polymerized PMMA materials exhibit very good clinical stability and low porosity, making them significantly more resistant than hand-mixed PMMA. Studies confirm their suitability for temporary restorations lasting several months. They are ideal for the test phase of complex restorations and enable precise aesthetic evaluation.
What role do metallic materials play in modern milling centers?
Titanium and CoCr remain essential materials for implant-supported constructions and metal frameworks. Milling processes offer high precision, reproducible fit, and good surface quality. Metallic materials remain indispensable, especially for highly stressed indications, bar constructions, or individual abutments.
How is the market for new materials developing?
The trend is clearly moving toward translucent zirconia, structured hybrid materials, and additively manufactured ceramics. In addition, sustainable materials and energy-efficient production methods are gaining in importance. Research and industry are increasingly working on materials that combine both aesthetic and mechanical properties.
