Dentistry – Method or material for testing – treating – restoring – or...
Reexamination Certificate
2000-01-03
2002-03-26
Lucchesi, Nicholas D. (Department: 3732)
Dentistry
Method or material for testing, treating, restoring, or...
C433S173000, C433S201100
Reexamination Certificate
active
06361318
ABSTRACT:
TECHNICAL FIELD
The present invention relates inter alia to a method for producing an elongate support element with associated seats for replacement structure in human body parts (jaw). By means seats of the support element can be applied to implants and/or to spacers on these implants. The longitudinal axes or center axes of the seats connect with or are parallel to the longitudinal axes or center axes of the implants in order to satisfy set accuracy of fit requirements which can be about 2/100 mm. The method starts from the stages of identification and possible modelling of the dental situation in question, supplying information, extracted from the identification and modelling, to computer equipment, operating the computer equipment to use the supplied information and further information input to the computer to simulate and determine the structure of the support element in or at the replacement structure. The method further includes; extracting, from the computer equipment, milling coordinates information or milling coordinates data used for controlling the milling of a blank in milling equipment, transmitting the milling coordinates information and milling coordinates data to the milling equipment and controlling the milling work equipment to produce the support element from the blank.
The invention also relates to an arrangement for producing an elongate support element with associated seats for replacement structure in human body parts/jaw, via by means of which seats the support element can be applied to implants and/or to spacers on these implants, where the center axes of the seats are arranged to connect with or be parallel to the center axes of the implants so that set accuracy of fit requirements are satisfied. The arrangement comprises identification members and possibly modelling members for identification and, respectively, modelling of the respective dental situation. Also included is computer equipment for receiving information extracted from the identification and modelling. Also included are first transmission members for transmitting the extracted information to the computer equipment, with which, on the one hand, the structure of the support element and the positioning in or at the replacement structure can be simulated and can be determined by means of the extracted information and further information input to the computer equipment, and; On other hand, milling coordinates information or milling coordinates data for controlling the milling of a blank in milling equipment can be executed with the aid of the said extracted and input information. Also included are second transmission members for transmitting the milling coordinates information (data) to the milling equipment for controlling the latter to produce from the blank.
The invention also relates to a product in the form of an elongate support element for a replacement structure (for example, dental bridge) for the human body, where the support element is designed with seats by means of which the support element can be applied to implants and/or to spacers on these implants. In accordance with the above, the center axes of the seats connect with the center axes of the implants so that fixed accuracy of fit requirements result.
The invention also relates to the use of recessing directly in the material of a blank in conjunction with the production of a dental product from the blank in milling equipment.
STATE OF THE ART
The features discussed in the introduction are known in the production of dental products, and also to some extent in connection with dental products in the form of elongate support elements of the described type. Reference is made to, inter alia, Swedish patents 9304042-6 and 9402351-2. It is also known to make recesses in dental products by means of so-called direct milling of the product material.
DESCRIPTION OF THE INVENTION
Technical Problem
In connection with the abovementioned methods and arrangements for producing dental products in the form of support elements, there are requirements for very great accuracy in the seat application. The required accuracy is, in accordance with the above, at least about 2/100 mm, and the requirements are set in order to be able to satisfy exact fitting in the jaw or equivalent. Poor fitting gives rise to stresses in the dentine or equivalent and causes discomfort and pain and even collapse of the bone in question, at least in the longer term. This has entailed comparatively technically complicated methods and arrangements for seat applications. The said methods include, inter alia, seat production by means of electro-erosion, in which a produced model is used as electrode part. The hitherto proposed methods and arrangements can include production of modules which are welded together (by laser welding) to form the final support element. Before the modules are put together, seat application can take place separately in one or more modules, for example by means of mechanical or optical measurement. However, the result of welding is a nonhomogeneous material in which the strength varies in the support element. Cavities may possibly arise in the material on account of the melt zone not penetrating down deep enough. When grinding or surface-machining the support element to adapt the shape, such cavities can become exposed, which means that the exactness or fit accuracy requirements cannot be satisfied. It has also been proposed to produce support parts by means of casting processes. In casting, there is the problem that the material may buckle upon cooling. The surface fineness in the contact seats can never be better than the grain size of the mould material. Particularly in the case of titanium casting, the molten metal can react chemically with the mould material, which can mean that the outermost material layer, about 1 mm thick, is heavily oxidized or forms an alloy, cf., for example in titanium casting, in the form of zirconium oxide in which the surface layer will consist of an alloy of titanium and zirconium. The strength will vary in the support element and there may be problems in obtaining support part elements with acceptable strength. In both welding and casting, the chemical composition of the surface therefore varies. In welding, the weld seam differs from the base material, and, in casting, ground areas differ from the raw cast surface. When ceramic is then to be baked onto the surface to form the tooth replacement, the adhesion varies greatly across the surface, the result of this being that there may be difficulties in obtaining products which are durable in the long term and which are suitable for implanting in, for example, the jaw. There is therefore a need for methods and arrangements and finished support elements, and the use of known methods known, which solve the abovementioned problems. The main object of the present invention is to provide a solution to these problems.
Solution
That which can principally be regarded as characterizing a method according to the invention is that the milling equipment, with the aid of the milling information or milling data, in addition to executing the support element shape determined in the computer equipment from the blank, can also be used for control in order to mill out the said seats directly in or out of the blank/support element material.
The arrangement according to the invention can principally be regarded as being characterized in that the milling coordinates information or milling coordinates data is designed, in addition to executing the support element shape determined in the computer equipment from the blank using the milling equipment, also to be used to control the milling equipment to shape and position the seats directly in the blank/support element material using the information likewise set in the computer equipment.
A product according to the invention can principally be regarded as being characterized in that the support element is made of homogeneous material and in that each seat wall is executed directly from the homogeneous support element material.
In embodiments o
Bäck Tomas
Carlsson Lennart
Petersson Anders
Connolly Bove & Lodge & Hutz LLP
Lucchesi Nicholas D.
Nobel Biocare AB
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