Dentistry – Apparatus – Having gauge or guide
Reexamination Certificate
1999-03-02
2001-11-20
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Having gauge or guide
C433S173000
Reexamination Certificate
active
06319000
ABSTRACT:
The present invention relates, in its first aspect, to a dental prosthesis system of the type set forth in the preamble to claim
1
. Other aspects of the invention relate to a positioning device of the type set forth in the preamble to claim
21
, to a drill-guiding insert of the type set forth in the preamble to claim
27
, to a set of such drill-guiding inserts of the type set forth in the preamble to claim
30
, to a fixture-guiding insert of the type set forth in the preamble to claim
31
, to a fixture-aligning device of the type set forth in the preamble to claim
32
and to a superstructure of the type set forth in the preamble to claim
34
. All of these other aspects of the invention are related to components intended for use with a dental prosthesis system in accordance with the invention's first aspect. The invention relates, in addition, to a method of attaching a superstructure to fixtures of the type set forth in the preamble to claim
39
, to a method for aligning a drilling device for making fixture holes of the type set forth in the preamble to claim
40
and to a method for emplacing a superstructure of the type set forth in the preamble to claim
45
.
It is known to implant fixtures in the jawbone of a toothless person. To make certain the fixtures are anchored permanently, a number of factors must be fulfilled with regard to, among other things, material selections and operation techniques. In practice, fixtures developed by Professor Branemark made of pure titanium with a micro-pitted surface have displayed very good long-term anchoring properties. The screw-shaped fixtures are operated into the jawbone where they are allowed to heal in—osseointegrate—throughout a certain time period, usually a few months. Teeth can thereafter be mounted in the fixtures, Most types of these implanted elements are provided with external threads—and are thus implanted screws—and they are attached by screwing them into holes made in the bone tissue. The holes are usually pre-threaded, but it is also possible to screw in self-tapping screws. Implanted elements normally require shorter or longer times for healing-in before they should be exposed to significant loads. On implanted elements, one can attach individual teeth, i.e. one tooth per element, but a number of implanted elements, at least two, can also serve as attachment points for a bridge structure containing several teeth or even a complete row of teeth. For this purpose, a suitable design for the free end of an implanted element could comprise, for example, internal threads in a cylindrical bore in a tooth element that engage external threads on the cylindrical attachment part of a single-tooth prosthesis.
A simple bridge structure intended for attachment to at least two implanted elements is known through SE-448 599 (patent application No. 8503580-6). The bridge structure incorporates an essentially rigid bridge base which is attached directly to the titanium elements by means of screws and mounting devices for removable attachment of a row of teeth on the bridge base. The advantages of a rigid bridge base include the fact that the row of teeth can be attached in a simple manner and that the bridge base is easy to produce. This known device is, however, disadvantageous because the spacer elements must be attached in the jawbone with precise parallelism and with their free ends in a pre-determined plane and spaced a pre-determined distance apart so that it will be possible to mount the bridge base without strain, instead of requiring individual adaptation in advance to the positions of the spacer element's free ends.
If this degree of accuracy cannot be achieved, which is probably the normal case, it is necessary to individually adapt the bridge base to the spacer elements. This adaptation is facilitated, as set forth for example in Swedish published specification No. 446 370, by a pillar-shaped spacer element that is mounted between each implanted element and the bridge structure. Both ends of the spacer element are conically tapered. The free end has a threaded bore so that it can be screwed into a mating hole in a dental prosthesis. Between the dental prosthesis and the conically-shaped free end part there is an arrangement consisting of a sleeve-shaped part having conical internal and external shell-surfaces. Even though this known device has a certain flexibility, the aforesaid specification calls for an impression of the pillar element positions, and possible necessary adjustment of the fit between the conical surfaces of the bridge and the sleeve-shaped parts before final mounting can take place.
To some extent, these disadvantages are avoided by a device that affixes dental bridges in accordance with Swedish patent application No. 8800082-3. Here, the spacer elements have cone-shaped free ends, and the bearing bridge structure incorporates sleeves designed with conical bores that are used to mount the conical ends of the spacer elements, wherewith each sleeve has two lateral vanes. The adjoining vanes on adjacent sleeves overlap each other, and they are joined by means of screws. However, the design/construction of this device is not optimal with regard to, among other things, hygiene, strength and mounting simplicity for a row of teeth.
The mounting of dental bridges requires a great deal of work, and as a result the costs of reconstructing a complete upper or lower jaw are relatively high. Moreover, reconstruction is very time-consuming, even for the patient. It is therefor desirable to reduce, by means of user-friendly implanting and mounting solutions, the amount of time and work needed for full-jaw reconstructions—including reconstructions that only involve a significant contiguous part of a row of teeth.
Through SE-501 174, a dental prosthesis system is known in which a dental bridge is attached with fixtures via fitting agents arranged between each fixture and the dental bridge's fastening devices. The fitting agents fit precisely the individual fixture's spacer elements and they also fit, but with a certain amount of clearance, the respective fastening devices on the dental bridge. The bridge can be affixed to the fitting agents by means of adhesive or hardening layers applied in the clearances, and the fitting agents are removably attachable to the respective spacer elements.
Through SE-500 851 a dental prosthesis system is also known in which a bridge base is fastened to fixtures attached in a person's jawbone. The fixtures are attached in the jawbone in four holes that are drilled using a jig. The bridge base can be supplied as a prefabricated element selected from an existing assortment of bridge bases.
When using dental bridges that require little or no processing in order to be adapted to the fixtures implanted in a person's jawbone, a technique has thus been used which is based on introducing adjustment or adaptation provisions for the bridge's attachment and also a technique in which a drilling jig is used in an attempt to achieve the necessary precision. This latter alternative imposes stringent requirements regarding how such a drilling jig or other positioning device is applied and handled when holes for the fixture are being drilled.
Against this background, the purpose of the present invention is to provide a dental prosthesis system and components for such a dental prosthesis system that will permit the use of prefabricated superstructures with minimized risk of misfits, thereby minimizing the need for individual adaptation of the superstructure when it is attached to the patient.
In accordance with the invention, this has been achieved through a dental prosthesis system of the type set forth in the preamble to claim
1
which displays the special properties set forth in the characterizing clause of this claim, through the use of a positioning device in accordance with the preamble to claim
21
, a drill-guiding insert in accordance with the preamble to claim
27
, a fixture-guiding insert in accordance with the preamble to claim
31
, a fixture-aligni
Lewis Ralph A.
Medevelop AB
Ostrolenk Faber Gerb & Soffen, LLP
LandOfFree
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