Computer based systems that allow the creation and use of electronic models of teeth impressions to design some types of dental appliances have been developed over time. Dental appliances include, by way of illustration, restorations, bridges, and implants. Restorations include, by way of illustration, replacements for single teeth including incisors, molars, and pre-molars. Dental appliances are designed to mount to either natural teeth or implanted teeth substitutes. For the sake of convenience, this disclosure will use the term “abutment” to refer to both natural teeth and implanted teeth substitutes.
In some prior systems, an electronic model for a dental restoration is designed to complement an electronic image of an abutment. The electronic image of the abutment can be generated based on a patient's actual abutment or a study cast thereof. The electronic image is then printed in wax using a rapid prototyping machine and cast or pressed using a standard lost-wax manufacturing process. However, these systems generally construct dental restorations as single-piece physical objects fabricated using a single type of material such as gold or ceramic. Furthermore, the wax models are susceptible to warping and deformation when exposed to high temperatures or physical force.
In some other prior systems, dental appliances are constructed by hand from multiple components. These components are designed, sculpted, and fabricated as separate items that are then mated into a single physical structure. Creating these components as separate items makes mating and matching these components difficult. The ability to mate these separate components into a single structure depends upon the skill of the designer or fabricator to construct complimentary components.
An anterior restoration (i.e., a restoration of an incisor or pre-molar) is one example of a dental appliance made by hand in previous systems. Anterior restorations are more visible to onlookers and so greater care is generally taken in their creation to ensure the restoration resembles a natural tooth as much as possible. For example, color may vary over the length or width of a natural tooth. Teeth are generally darker in color closer to the gums. Furthermore, calcium deposits or staining may cause discoloration on the enamel of the tooth. In addition, color striations, often referred to as the Stria of Retzius, are caused by grooves or other such recesses formed in the enamel of the tooth during development. The resulting variation in thickness of the enamel causes an onlooker to see variations in color in the enamel of the tooth. One current solution for creating anterior restorations relies generally on hand painting each restoration to match the patient's other teeth.
The present invention addresses the above and other limitations of prior dental electronic modeling systems.