## 3 Fabrication Methods
### Other Emerging Methods
Soon, 5 Dp will surpass all 3D and 4D printing methods. Five-dimensional printing is a new method to design several orthodontic components, crowns, implanted devices, and accessories used in healthcare and dental surgery. Furthermore, 5 Dp devices will be more durable than 3D- and 4D-based printing devices. The emerging technology of 5 Dp holds significant promise for creating curved shape designs in various fields, including dentistry. Applications such as dentures, artificial bones, stents, and complex dental tools can greatly benefit from 5 Dp's ability to produce intricate and custom-shaped objects. Moreover, this innovative technology is expected to facilitate the development of wearable sensors for dental applications. With its unique capabilities, 5 Dp is poised to enable the creation of complex wearable instruments that can enhance dental diagnostics and treatment. As a result, we can anticipate a wide range of successful applications for 5 Dp in the field of dentistry and beyond. Figure 14: (**a**) Schematic diagram of 5D printing [204], and (**b**) printing of cap using 5 Dp [204]. Figure 13: (**a**) 3 Dp and 4 Dp [197], and (**b**) temporary and recovered shapes of 4 Dp shapes [200]. A recent study conducted in Greece introduced the concept of 6D printing (6 Dp) in the literature. Figure 15 showcases the integration of 4 Dp and 5 Dp technologies within the 6 Dp process. The study suggests that 6 Dp will utilise five dimensions to generate designs that possess intelligent properties and the ability to change shape in response to environmental stimuli. By leveraging the advancements made in 5 Dp, the development of smart materials has paved the way for the creation of 6 Dp products with unique and intelligent behaviour [206]. Moreover, the utilisation of 6 Dp in the food industry holds promise for the creation of robust and highly responsive materials. In orthopaedics, 6 Dp technology can be employed to develop smart casts that offer innovative solutions for treating conditions like clubfoot and bone fractures, including congenital talipes equinovarus. The utilisation of smart materials (SMs) in 6 Dp technology allows for the precise application of mechanical loads, facilitating optimal alignment of fractured forearms or malleoli in orthopaedic applications. The smart cast can adapt its shape based on the presence or absence of oedema in the affected limb. This approach offers significant advantages, including the potential to eliminate the need for serial casting and the ability to customise the cast to gently guide the foot into the correct position for clubfoot treatment. Furthermore, the inherent flexibility of the 6 Dp process, along with efficient setup configurations, may lead to reduced material consumption and faster processing times [204]. The concept for the new printing method, which combines the 4 Dp and 5 Dp, is depicted in Figure 15[205; 206; 207]. To summarise, the emerging technologies of 4D, 5D, and 6D printing are currently being explored by researchers to enhance the design and production of intelligent structures using AM techniques. The integration of multi-dimensional capabilities with 4D printing offers the potential to create highly advanced smart objects, leading to significant advancements in medical and orthopaedic applications. The continuous investigation and improvement of these techniques will contribute to the overall impact of AM methods in various domains, benefiting society. Six-dimensional printing is a relatively new area of AM; it is anticipated to expedite the research into finding complex materials. It produces lighter, stronger designs that are more sensitive to their environment. However, the setup and operation costs for 6 Dp are anticipated to be signifi  
Figure 15: 1D to 6D printing method in the visual (**a–d**): dimensionality clarification [205; 206]. will continue to advance toward diversifying the materials, architectures, and fabrication techniques.