Temporary cylinder

Abstract: The invention relates to a cylinder 1 designed to be inserted in a temporary, implant-supported dental bridge/dental prosthesis, a so-called temporary cylinder, and which comprises an upper part 2 which is surrounded by the dental bridge/dental prosthesis and a base section 4 for connection to the spacer element 6 of the implant. The cylinder is made of a polymer material and the upper part 2 has a conical outer contour.

Description: The present invention relates to a cylinder of the type which is designed to be inserted in a temporary, implant-supported dental bridge/dental prosthesis, a so-called temporary cylinder, and which is made of a polymer material. The cylinder comprises an upper part which is surrounded by the dental bridge/dental prosthesis, and a base section for connection to the spacer element of the implant. The upper part has a conical outer contour provided with grooves for increased retention against the surrounding bridge/dental prosthesis. It is already known to permanently anchor a dental prosthesis in the jaw with the aid of titanium screws implanted in the jawbone. The screws are anchored in holes in the bone in such a way that the upper part of the screw is located level with or immediately below the top surface of the jawbone. The screw is then covered over with a flap of mucous membrane and is left unloaded for a rest period of 3 to 6 months so that the bone can grow securely to and form a unit with the implanted screw. After the rest period the screw is exposed and a spacer element, preferably also of titanium, is arranged on the screw, after which a dental prosthesis is anchored on the spacer element. The dental prosthesis must in this case be adapted accurately to the actual appearance of the jaw with the implanted titanium elements. After the spacing operation has been carried out, the patient treated wants to have the dental prosthesis ready as soon as possible. At present it takes a relatively long time for an aesthetically optimal dental prosthesis to be produced. This is partly because the skilled work of dental technicians and dentists takes a certain time to carry out, but primarily because the mucous membrane/gum around the spacers in most cases recedes, and this means that the spacers may become visible. In most cases this is undesirable. Many dentists therefore want to produce a temporary dental prosthesis/dental bridge which is relatively simple in its design and in which the aesthetically optimal solution is not sought. In terms of the work involved, such a dental prosthesis is simpler and quicker to produce, which means that the patient is given it very soon after the spacing operation. When the mucous membrane has receded after a month or a few months, it is possible to begin work on the final dental bridge. Hitherto, these temporary solutions have involved the use of gold cylinders which are intended to be cast into the finished dental bridge, However, these cylinders are relatively expensive, primarily on account of high material costs, since they are made of an alloy consisting of gold and platinum. Temporary bridges can be divided into two types: those which are made entirely of acrylic resin and those which have a cast metal skeleton in order to give them increased strength. There are in addition on the market metal cylinders made from less expensive material which are intended for temporary use. These cylinders can be made of, for example, aluminium or stainless steel. However, these materials are not entirely satisfactory: aluminium on account of toxicity, and stainless steel on account of the tendency to corrosion together with titanium. In addition, these cylinders also require a mechanical working which, if it is to be carried out with precision, is relatively costly. FR-A-2 623 709 relates to a tubular dental implant system in which a solid spacer element made of a polyurethane material is used. Such a spacer element is not suitable, however, for a temporary dental bridge. It is not connected to the spacer element, it is connected to the implant by means of an outer threading. Furthermore it does not indicate how to connect the temporary dental bridge by a securing screw. The aim of this invention is to provide a cylinder for temporary use which solves the above problems. The feature which in this case may principally be regarded as characterizing the invention emerges from patent claim 1. One embodiment of the invention is shown diagrammatically on the attached drawing. The cylinder is made of a high-strength, non-toxic structural polymer, for example polyetheretherketone PEEK. It is designed in such a way that greater flexibility is obtained as regards the manner of application. Previously known temporary cylinders have an outer contour of essentially cylindrical shape. This means that they must be joined together with the dental bridge outside the patient's mouth. In most case this is carried out in a dental laboratory. In contrast to these previously known temporary cylinders, the cylinder 1 according to the invention has an upper part 2 of conical outer shape, which means that the joining together can also be performed in the patient's mouth, which can be of great advantage if, for example, it is desired to convert the patient's old dental prosthesis to an implant-supported temporary bridge directly upon connection of the spacer. In this case, the conical seats are filled up in this dental prosthesis and the dental bridge is cemented, or alternatively fitted with so-called cold-setting acrylate, on the temporary cylinders screwed into the patient. The conical upper part 2 merges at the bottom, via an annular shoulder 3, into a conical, downwardly tapering base section 4 which is intended to bear against a shoulder of a conical spacer, for example a conical spacer according to SE 8903038-1, arranged on a fixture. In order to increase the retention against the surrounding dental bridge, the outer contour of the cylinder is provided with grooves 5. The cylinder 1 is sleeve-shaped and has a through-hole (screw-channel) which consists of an upper cylindrical recess 6, a seat 7 for the screw (not shown in the figure) which holds the cylinder securely against the conical spacer, and a lower conical opening 8 inside which the upper conical section of the spacer is accommodated. The conical upper part of the cylinder is made with a cylindrical top portion 9. The cylindrical top portion 9 has substantially the same length as the conical upper part of the cylinder. Such embodiment then provides an increased surface between the cylinder and the temporary bridge, which means increased stability between the cylinder and the acrylic temporary bridge, and also an elongated channel 10 for the bridge securing screw. If this type of cylinder is used with a separate outer sleeve, however, then the cylindrical top portion 9 is shortened, preferably the cylinder is cut at the top groove 5'. The grooves then serve both as retention means and cutting marks for shortening the cylinder.

Claims: Cylinder to be inserted in a temporary, implant-supported dental bridge/dental prosthesis, a so-called temporary cylinder made of a polymer material which cylinder (1) comprises an upper part (2) which is surrounded by the dental bridge/dental prosthesis and a base section (4) for connection to the spacer element of the implant, said upper part (2) having a conical outer contour provided with grooves (5) for increased retention against the surrounding dental bridge/dental prosthesis characterized in that the conical upper part (2) has a cylindrical top portion (9). Cylinder according to claim 1 characterized in that the conical upper part (2) merges into its base section (4) via an annular shoulder (3), and in that the base section too has a conical outer contour which, however, tapers downwards in order to fit to the outer contour of spacer element. Cylinder according to claim 1 characterized in that it is designed to cooperate with an outer sleeve which fits on the cylinder (1) with a suitable play in such a way that any dimensional changes during the casting process or during polymerization of the bridge framework can be accommodated. Cylinder according to claim 3 characterized in that the outer sleeve is made of a burn-out resin. Cylinder according to claim 3 characterized in that the base section of the outer sleeve bears against the annular shoulder (3) of the cylinder. Cylinder according to claim 1 characterized in that the cylindrical top portion (9) has substantially the same length as the conical upper part (2) of the cylinder. Cylinder according to claim 2 characterized in that the upper groove (5') is used as a cutting mark for shortening the cylinder.

Inventors: EDGREN STEFAN, JOERNEUS LARS, SVENSSON THOMAS, EDGREN, STEFAN, JOERNEUS, LARS, SVENSSON, THOMAS, Jörnéus, Lars
Applicants: NOBEL BIOCARE AB, NOBEL BIOCARE AB (REG. NO. 556002-0231)
Application year: 1992
Main classification: A61C8
IPC codes: A61C8, A61C13