Dentistry – Prosthodontics – Holding or positioning denture in mouth
Reexamination Certificate
2000-06-07
2001-09-18
Lewis, Ralph A. (Department: 3732)
Dentistry
Prosthodontics
Holding or positioning denture in mouth
Reexamination Certificate
active
06290500
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to restorative dentistry and other medical procedures and more particularly to surgical implementation in the mouth of a patient and to prosthesis systems and methods used with such prosthesis systems.
BACKGROUND OF THE INVENTION
The natural teeth of an individual may be lost as a result of dental disease or trauma, making it desirable to replace such teeth with one or more prosthetic devices. An example of a prosthetic device is the dental implant which is surgically positioned within the mandibular or maxillary alveolar bone.
One type of dental implant has a first implant member for placement in an osteotomy site in the alveolar bone of a patient. Following healing, a head member, commonly called an abutment, is mounted in or on the first implant member and a tooth simulating prosthesis or crown is then mounted on the abutment. A successful system of this type is disclosed in U.S. Pat. No. 4,738,623. In that patent, a first implant or root member having a first or outer end formed with a female socket circumscribed by a shoulder and having a suitable anchoring means, such as outwardly extending fins, is placed in an osteotomy site or implant receiving cavity formed in the alveolar bone with suitable surgical instruments and techniques. The first implant member is inserted into the cavity with the upper portion of the member a selected distance below the opening of the cavity, that is, below the crest of the bone, e.g., two or three millimeters. A healing plug is inserted into a female socket of the first implant member and particles of a natural and/or synthetic bone growth stimulating grafting material are then packed within the cavity around the shoulder of the implant member and the wound is then closed.
Following healing, the dentist accesses and removes the plug and replaces it with an abutment. The abutment has a male portion received within the female socket and an intermediate, outer generally hemispherical surface portion which may extend through the surface of the gingiva and preferably through the surface of the crest of the bone which may have been previously reamed to form a complimentary configuration when forming the cavity. A prosthetic device can then be attached to the abutment forming a smooth continuous surface with the hemispherical surface portion of the abutment with the interface between the prosthetic device and the abutment being supragingival or, for best aesthetics, subgingival, that is, being covered by the gingival tissue. Fabrication of the prosthetic device typically involves making an impression, generally a full arch impression, and pouring a model forming, inter alia, a positive replica, or die, of the abutment head. A laboratory technician then burnishes platinum foil over the die which then serves as a core on which a prosthesis is built. Upon completion and firing of the prosthesis, the platinum is scratched away. Although this procedure has been acceptable, the efficacy of the result is dependent upon the skill of the technician and is highly labor intensive and time consuming. Alternatively, the technician could fabricate the prosthesis by a lost wax technique utilizing a central core of metal, usually a gold palladium alloy, onto which porcelain powders are added and fused in a firing oven. Still other techniques for prosthesis fabrication include the use of implant and abutment analogs, acrylics or composite resins. However, such methods are also highly labor intensive and time consuming.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an implant system and method which minimizes laboratory procedures and concomitant expenses and time delays. Another object of the invention is the provision of an improved implant system and method in which consistent accuracy of the component parts, as well as the implant as a whole, is enhanced. Another object of the invention is the provision of a system and method for overcoming the above noted prior art limitations.
Briefly stated, a first embodiment of the invention comprises an abutment having a central portion between a post portion and a head portion, the post portion being receivable in the bore of a dental implant and the central portion being formed with a smoothly curved, convex outer surface extending from a relatively large periphery progressively down to a smaller periphery which joins the post portion. The head portion has a smaller outer periphery than that of the relatively large periphery of the central portion with a shelf formed between the base of the head portion and the central portion which forms an angle with a plane perpendicular to the longitudinal axis of the head portion within a range of approximately 0-30 degrees to facilitate the forming of a confluent joint with a prosthesis received on the head portion which is compatible with a human body, i.e., one which the body will not try to reject. The shelf slopes downwardly toward the post portion end with respect to a direction going radially outwardly from the longitudinal axis. More preferably, the angle is approximately 15 degrees. The provision of the angled shoulder permits the use of a prosthesis having a matching shoulder at the entrance to a head receiving cavity and having any one of various emergence profiles, that is, the interface of the prosthesis and the abutment can be on the shelf either flush with or inboard of the outer periphery thereof and still be compatible with the human body. Generally, the curved surface of the central portion of the abutment is generally spherical however it can also be of other smoothly curved configurations, such as ellipsoidal. Preferably, the implant is formed with a bore having a self-holding taper of less than 5 degrees and the post is formed with a matching self-holding taper. However, if desired, the bore and post could be threaded or the post could have no taper and be attached to the implant by cement or the like.
According to another feature of the invention, an integrated crowned abutment is formed by providing a sleeve of suitable material, such as porcelain, metal, resin or the like, having an internal head seat with a negative image closely matching that of a head portion of an abutment having a selected configuration so that the sleeve can be fitted precisely onto such a head portion. The sleeve is placed on the head portion of a temporary abutment having the selected configuration and having a post removably inserted in the bore of an implant positioned in an osteotomy site. An impression of moldable material is taken of the removable abutment and the area adjacent to the osteotomy site. The impression is removed from the patient's mouth with the sleeve remaining in the impression. A transfer abutment having a head portion with the same selected configuration is placed within the sleeve and the transfer abutment is inserted in an implant analog. Molding material is then poured into the impression to form a model or replica of the area adjacent to the osteotomy site with the implant analog locked in the model. The model is removed from the impression and the sleeve is removed from the impression and positioned on the transfer abutment in the model. A prosthesis is then built on the sleeve by adding suitable material such as porcelain, metal, resin and the like, and shaping the material within the available space between teeth or prostheses contiguous with and opposing the osteotomy site. The prosthesis is then attached to a permanent abutment having a head portion with the selected configuration by any suitable means, such as cementing, clipping, frictionally engaging as with a self-holding taper, or the like, to form an integrated crowned abutment. The integrated crowned abutment can be polished extraorally to remove extraneous cement when cement is used as the means of attachment and then the finished abutment can be inserted into the implant with the angular position being adjustable to any desired orientation and then locked in place. Preferably, the implant is provided with a bo
Driskell Thomas D
Morgan Vincent J
DIRO, Inc.
Huag John A.
Lewis Ralph A.
LandOfFree
Dental implant system and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dental implant system and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dental implant system and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2521954