Computer-aided Fabrication Of A Removable Dental Prosthesis

Abstract

A method and system for fabricating a dental prosthesis are provided. High resolution digital scanned images of a patient's oral structures are acquired. Three dimensional (3D) cone beam X-ray images of hard and soft oral tissues are acquired. The scanned images are integrated with the 3D cone beam X-ray images in a 3D space to obtain combined three dimensional images of the oral structures. The occlusal relationship between upper and lower oral structures are digitally simulated using the combined three dimensional images. The dental prosthesis is digitally modeled for planning intra-oral positioning and structure of the dental prosthesis. The digital dental prosthesis model is refined based on simulated force tests performed for assessing interference and retention of the digital dental prosthesis model. A prospective dental prosthesis model is created based on the refined digital dental prosthesis model. The dental prosthesis is fabricated based on a verified prospective dental prosthesis model.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation application of non-provisional patent application Ser. No. 12 / 774,222, titled “Computer-Aided Fabrication Of A Removable Dental Prosthesis” filed on May 5, 2010 in the United States Patent and Trademark Office. The specification of the above application is incorporated by reference herein in its entirety.BACKGROUND[0002]Dental prostheses are prosthetic appliances that replace missing teeth to aid mastication and improve facial esthetics, phonetics, and self esteem. Removable dental prostheses include dentures, partial dentures, and detachable fixed prostheses. The traditional methods of fabricating removable prostheses rely on alginate or silicone impressions of bone, soft tissue structures, and the dentition of a patient. These methods usually require multiple patient visits to obtain a clinically acceptable impression. The impressions are poured with dental stone to obtain model casts or replicas of the upper and ...

AI Technical Summary

Benefits of technology

"The patent describes a computer-aided method and system for designing and fabricating a highly retentive, functional, and esthetic removable dental prosthesis. The system uses three-dimensional images of the patient's oral structures to create a digital model of the dental prosthesis. This model is then used to plan the position and structure of the dental prosthesis to achieve optimal occlusion, retention, and smile profile. The dental prosthesis is fabricated based on the refined digital model and undergoes a milling process for further detailing. The technical effects of the invention include improved design accuracy, reduced interference and improved retention, and improved esthetics and phonetics."

Problems solved by technology

Due to the involvement of the masticular muscle groups, there have been controversies over the definition and method of obtaining accurate occlusion data.

Moreover, these prostheses require extensive adjustments and multiple additional visits, and also do not guarantee patient satisfaction.

While every step in the dental clinic and the dental lab requires tedious and precision-driven labor, human errors are inevitable.

Furthermore, there are many inherent sources of errors that are difficult to control, for example, soft tissue deformation during impression, limitations of the semi-adjustable articulator, controversies over proper form of occlusion, and shrinkage of acrylic material during polymerization.

A major problem involving removable prosthesis is the retention of the prosthesis.

Although the acrylic material adapts to the shape of the plaster cast model initially, the acrylic base shrinks and deforms during the polymerization process, thereby losing its precise seal to the plaster model and the soft tissue.

On the other hand, over retention due to lack of precision in metal framed partial dentures is also a problem.

Over retention not only causes pain and discomfort, but also damages the anchoring teeth in the long term.

Due to the lack of technology to precisely shape the base or anchor area of the prosthesis, current methods mostly rely on multiple clinical adjustments by the dentist using pressure-indicating paste, which still does not warrant a tight seal or fit to the tissue surfaces.

Dentists often spend significant time adjusting the base of the prosthesis and patients are generally unhappy with the outcome.

Another problem is improper occlusion due to inaccurate face bow transfer or the absence of a face bow transfer.

This results in unbalanced occlusion interference, improper teeth alignment, or insufficient occlusion space, which further reduce the retention.

As a result of these unresolved problems, the service of removable prostheses is currently under-valued and under-served in the dental industry.

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