A dental crown is a custom-made cap placed over a damaged or weakened tooth to restore its original shape, size, strength, and appearance. The creation of a dental crown is a precise partnership between two distinct entities: the clinical team and the technical fabrication team. This collaboration ensures the final prosthetic is functional, durable, and aesthetically blends with the natural dentition.
The Role of the Dental Clinician
The process begins in the dental office, where the dental clinician assumes the role of diagnostician and surgeon. The first step involves preparing the tooth by removing decay and carefully shaping the tooth structure to create a stable foundation for the crown. This preparation is meticulous, as the amount of tooth reduction dictates the final thickness and strength of the restorative material.
After preparation, the clinician captures a three-dimensional record of the prepared tooth and surrounding anatomy. This is often done using impression material or, increasingly, with an intraoral digital scanner that creates a precise computer file. The clinician then issues a detailed prescription, specifying the crown’s required material composition, the exact shade match to adjacent teeth, and the desired fit against the opposing bite, known as occlusion.
The Dental Laboratory: The Crown Fabricators
The physical manufacturing of the crown is the responsibility of the specialized team working in a dedicated dental laboratory. These professionals are Dental Technicians. The laboratory receives the clinician’s prescription and the physical impression or digital scan file.
The technician’s skill lies in translating the prescription into a three-dimensional, functional, and aesthetic restoration. They begin by creating an accurate physical model from the impression or a virtual model from the digital scan. Using this model, the technician designs the crown’s contours, ensuring the margins fit seamlessly onto the prepared tooth structure and that the crown harmonizes with the patient’s bite. This process requires a sophisticated understanding of dental anatomy, material science, and artistic skill.
Methods of Crown Fabrication
Dental laboratories employ two primary approaches to fabricate the final crown, depending on the material and the clinician’s preference. The traditional method relies on lost-wax casting and ceramic layering, used to create metal and Porcelain-Fused-to-Metal (PFM) crowns. This method involves fabricating a wax replica of the final crown, which is then encased in an investment material and burned away, leaving a mold for molten metal or ceramic powders.
Modern fabrication relies on Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) technology. The digital scan or model is imported into CAD software, where the technician designs the crown virtually. Once the design is finalized, the CAM process takes over, either instructing a milling machine to carve the crown from a solid block or utilizing 3D printing. This digital workflow offers enhanced accuracy and efficiency, often allowing for rapid turnaround from the laboratory.
Types of Materials Used in Crown Creation
The selection of material is determined by the tooth’s location, the patient’s bite forces, and aesthetic requirements.
Porcelain-Fused-to-Metal (PFM)
This long-standing option features a metal alloy substructure covered by layers of tooth-colored ceramic. The metal core provides superior strength for back teeth, while the porcelain exterior offers a natural appearance.
All-Ceramic Crowns
All-ceramic crowns have become increasingly popular for their excellent aesthetics and biocompatibility, as they contain no metal.
Lithium Disilicate
Often marketed as E-max, this glass-ceramic material is prized for its translucency. This makes it a preferred choice for highly visible front teeth restorations.
Zirconia
Zirconia is a very dense ceramic oxide known for its exceptional fracture resistance. It is milled from a solid block and provides a blend of strength rivaling metal crowns and a pleasing, tooth-like appearance. This makes it suitable for both anterior and posterior applications.