Three-dimensional (3D) printing technologies are advanced manufacturing technologies based on computer-aided design digital models to create personalized 3D objects automatically. They have been widely used in the industry, design, engineering, and manufacturing fields for nearly 30 years. Three-dimensional printing has many advantages in process engineering, with applications in dentistry ranging from the field of prosthodontics, oral and maxillofacial surgery, and oral implantology to orthodontics, endodontics, and periodontology. This review provides a practical and scientific overview of 3D printing technologies. First, it introduces current 3D printing technologies, including powder bed fusion, photopolymerization molding, and fused deposition modeling. Additionally, it introduces various factors affecting 3D printing metrics, such as mechanical properties and accuracy. The final section presents a summary of the clinical applications of 3D printing in dentistry, including manufacturing working models and main applications in the fields of prosthodontics, oral and maxillofacial surgery, and oral implantology. The 3D printing technologies have the advantages of high material utilization and the ability to manufacture a single complex geometry; nevertheless, they have the disadvantages of high cost and time-consuming postprocessing. The development of new materials and technologies will be the future trend of 3D printing in dentistry, and there is no denying that 3D printing will have a bright future.

In this review, we describe the application of thermosensitive hydrogels composed of poloxamer in medicine, especially for oral cavities. Thermosensitive hydrogels remain fluid at room temperature; at body temperature, they become more viscous gels. In this manner, the gelling system can remain localized for considerable durations and control and prolong drug release. The chemical structure of the poloxamer triblock copolymer leads to an amphiphilic aqueous solution and an active surface. Moreover, the poloxamer can gel by forming micelles in an aqueous solution, depending on its critical micelle concentration and critical micelle temperature. Owing to its controlled-release effect, a thermosensitive gel based on poloxamer 407 (P407) is used to deliver drugs with different characteristics. As demonstrated in studies on poloxamer formulations, an increase in gelling viscosity decreases the drug release rate and gel dissolution time to the extent that it prolongs the drug’s duration of action in disease treatment. This property is used for drug delivery and different therapeutic applications. Its unique route of administration, for many oral diseases, is advantageous over traditional routes of administration, such as direct application and systemic treatment. In conclusion, thermosensitive gels based on poloxamers are suitable and have great potential for oral disease treatment.

With the development of ceramic technology, prosthodontic ceramics are becoming a useful option for improving esthetic outcomes in dentistry. In this paper, various ceramic materials were reviewed and evaluated, and their advantages and disadvantages and indications in oral prosthodontics were analyzed objectively. The properties of resin‐based ceramics, polycrystalline ceramics, and silicate ceramics were compared and analyzed. Resin‐based ceramics may replace other ceramic materials in the CAD/CAM field.

Background: The sagittal alignment of the spine changes depending on body posture and degenerative changes. This study aimed to observe changes in sagittal alignment of the lumbar spine with different positions (standing, supine, and various sitting postures) and to verify the effect of aging on lumbar sagittal alignment. Methods: Whole-spine lateral radiographs were obtained for young volunteers (25.4 ± 2.3 years) and elderly volunteers (66.7 ± 1.7 years). Radiographs were obtained in standing, supine, and sitting (30°, 60°, and 90°) positions respectively. We compared the radiological changes in the lordotic and segmental angles in different body positions and at different ages. Upper and lower lumbar lordosis were defined according to differences in anatomical sagittal mobility and kinematic behavior. Results: Lumbar lordosis was greater in a standing position (52.79° and 53.90° in young and old groups, respectively) and tended to decrease as position changed from supine to sitting. Compared with the younger group, the older group showed significantly more lumbar lordosis in supine and 60° and 90° sitting positions (P = 0.043, 0.002, 0.011). Upper lumbar lordosis in the younger group changed dynamically in all changed positions compared with the old group (P = 0.019). Lower lumbar lordosis showed a decreasing pattern in both age groups, significantly changing as position changed from 30° to 60° (P = 0.007, 0.007). Conclusions: Lumbar lordosis decreases as position changes from standing to 90°sitting. The upper lumbar spine is more flexible in individuals in their twenties compared to those in their sixties. Changes in lumbar lordosis were concentrated in the lower lumbar region in the older group in sitting positions.

Guided tissue/bone regeneration (GTR/GBR) is commonly applied in dentistry to aid in the regeneration of bone/tissue at a defective location, where the assistive material eventually degrades to be substituted with newly produced tissue. Membranes separate the rapidly propagating soft tissue from the slow-growing bone tissue for optimal tissue regeneration results. A broad membrane exposure area, biocompatibility, hardness, ductility, cell occlusion, membrane void ratio, tissue integration, and clinical manageability are essential functional properties of a GTR/GBR membrane, although no single modern membrane conforms to all of the necessary characteristics. This review considers ongoing bone/tissue regeneration engineering research and the GTR/GBR materials described in this review fulfill all of the basic ISO requirements for human use, as determined through risk analysis and rigorous testing. Novel modified materials are in the early stages of development and could be classified as synthetic polymer membranes, biological extraction synthetic polymer membranes, or metal membranes. Cell attachment, proliferation, and subsequent tissue development are influenced by the physical features of GTR/GBR membrane materials, including pore size, porosity, and mechanical strength. According to the latest advances, key attributes of nanofillers introduced into a polymer matrix include suitable surface area, better mechanical capacity, and stability, which enhances cell adhesion, proliferation, and differentiation. Therefore, it is essential to construct a bionic membrane that satisfies the requirements for the mechanical barrier, the degradation rate, osteogenesis, and clinical operability.