Screw-type dental implant.

p0001The invention relates to a screw implant for fastening dentures to the jaw according to the preamble of claim 1.

p0002are used screw implants for fixing dental prostheses, in particular dentures and individual teeth, the jaw. The screw implants are to largely screwed into a pre-receiving bore in the jaw. Known screw implants of this type have in particular in the head region on a design that leads upon insertion into the receiving bore of the jaw to Verquetschungen in which can cause jaw decelerating Trauma a the healing of the screw implant. Finally, the known screw implants often offer only insufficient maintenance in the jaw.

p0003Proceeding from this, the present invention seeks to provide a screw implant, which can easily be inserted into the jaw and herein einheilt both quickly and firmly.

p0004A serving to achieve this object, screw implant has the features of claim 1. The middle section with a thread of smaller depth two is achieved: firstly, the gum is at the transition to non-threaded head portion due to the lower thread depth is expanded or biased, thereby sealing manner at the central portion of the screw implant. During Einheilprozesses the screw implant into the jaw is prevented by bacteria or other contaminants in a gap between the screw implant and the jaw or gum penetrate. On the other hand is increased by the reduced thread depth of the core diameter at the central portion, whereby here the available wall thickness becomes larger. This allows for easier placement of a tool receiving means, in particular a hexagon socket, inside the screw implant. This Allen can then namely also cover the central portion of both the head portion as.

p0005Advantageous developments of the screw implant will be apparent from the dependent claims.

p0006Preferred embodiments of the invention are described with reference to the drawing. Therein:<dl id="dl0001"><dt>Fig. 1</dt><dd>a greatly enlarged longitudinal section of a screw implant, </dd><dt>FIG. 2</dt><dd>a view of the screw implant of FIG. 1 from above, and</dd><dt>Fig. 3</dt><dd>shows an enlarged detail III of FIG. 1.</dd></dl>

p0007The figures show greatly enlarged a screw implant 81 for screwing or screwing into a prefabricated receiving bore in the jaw. After healing in the jaw, the screw implant forms 81 a fixed, non-rotatable base for screwing, for example, prostheses or artificial (singles) teeth.

p0008The screw implant 81 has an elongate, cylindrical implant body 21. This is formed of a stainless metal material, in particular titanium. Starting from a pine outward face 22 of the implant body 21 is provided with a central threaded bore 23rd This extends toward a longitudinal central axis 24 in the interior of the implant body 21. In the upper end region of the threaded bore 23 is provided with a frustoconical widening 25 which tapers starting from the end face 22 to the threaded bore 23 towards. The taper has referred to the longitudinal central axis 24 at an angle which is slightly smaller than the angle of the frusto-conical widening 25 about corresponding frustoconical approach to a aufzusetzendes on the screw implant 81 (not shown) body part. Characterized the mounting part seals the truncated cone-shaped widening 25 at a position on the end face 22 from edge to prevent the penetration of dirt or the like in the interior of the screw implant 81, in particular the threaded bore 23rd

p0009The outer shell of the implant body 21 is partially provided with an external thread. The outer jacket of the screw implant 81 consists namely of three sections together, namely a lower threaded section 82, an adjoining middle portion 83 and an upper head portion 84. A of a mandibular (lower) end face 31 outbound portion of the external thread is a self-tapping external thread 32 educated. This extends approximately over half the length of the screw implant 81. In the self-cutting external thread 32 joins towards the (upper) end face 22 a pure screw thread 33 on. The external thread is designed as a metric thread, but can also be a trapezoidal or round thread be.

p0010The lower self-tapping external thread 32 is firstly formed from the screw 33, which the self-cutting the upper part of the male thread continuously passes to the (lower) end face 31 to the other has the self-cutting external thread 32 via a plurality of recesses 34. There are shown embodiment four available at every 90 ° staggered recesses 34th They are formed by cut-outs on the periphery of the implant body 21 with mutually orthogonal surfaces. The radially directed surfaces form cutting surfaces 35. They lie on two 90 ° phase-shifted longitudinal midplane of the implant body 21. Perpendicular to the cutting faces 35 running (extended) surfaces define open areas 37 that are parallel to the respective longitudinal center plane. The outer edges of the cutting surfaces 35 form cutting edges 38. The lying on the respective cutting edge 38 tangent to the circumference of the implant body 21 is perpendicular to the cutting surface 35th

p0011A lower portion of the self-tapping external thread 32 tapers toward the (lower) end face 31 of the implant body 21. As a result, the insertion of the screw implant 81 is facilitated in the prepared in the jaw receiving bore and the cutting of the thread.

p0012In implant body 21 a lower blind hole 40 is located. This extends, starting from the (lower) end face 31 of the implant body 21 24, in the direction of its longitudinal central axis of the lower end portion of the blind bore 40 is a transverse to the longitudinal central axis 24 extending (first) associated transverse bore 41st This intersects the blind bore 40 and communicates with this thus in association (Fig. 1). The transverse bore 41 is formed as a through hole, such that it forms opposite openings in the implant body 21st

p0013On the (first) cross-bore 41 a (second) is arranged transverse bore 42nd This is offset by 90 ° to the (first) cross-bore 41, so that their parallel horizontal longitudinal central axes 43, 44 intersect. The longitudinal central axes 43 and 44 also intersect the longitudinal center axis 24 of the implant body 21 (FIG. 1). The distance of the cross bores 41 and 42 is selected such that they do not intersect or touch (Fig. 1).

p0014The central portion 83 has as the threaded portion 82 via an external thread, the external thread of the threaded portion 82 continues to run continuously over the entire central portion 83. The depth of the external thread is at the central portion 83 but less than the threaded portion 82. As shown in the FIG. 3 can be seen, the (normal) core diameter d of the threaded section 82 in the area of ​​the central portion 83 enlarged. This gives the central portion 83 over an increased core diameter dm, which is located approximately between the core diameter d and the pitch diameter D of the regular thread on the threaded portion 82nd The pitch diameter D is both the threaded portion 82 and the central portion 83 of equal size (Fig. 3). The transition between the core diameter d and the enlarged core diameter dm may be formed as the illustrated embodiment of FIG. 3 of a slant 85th But it is also conceivable to design the transition sharp.

p0015The core diameter dm is the same over the entire length of the central portion 83rd But it is also conceivable that the core diameter dm of the threaded portion 82 to the head portion 84 toward increased by expanding from the normal core diameter d at the threaded portion 82 to the diameter of the (smooth) head portion 84th

p0016From Fig. 1 will be seen that the enlarged core diameter dm corresponds to the area of ​​the central portion 83 the diameter of the unthreaded, preferably smooth and polished, where appropriate, the head portion 84. This has the groove base of the grooves of the thread part at the center portion 83 has a diameter corresponding to the diameter of the head portion 84th

p0017The screw implant 81 has a tool receiving means, which is designed as a hexagon socket 86th The hexagon socket 86 is based on the (upper) end face 22 of Sch consuming implant 81 and extends from there over the entire head portion 84 and over the greater part of the middle section 83. Due to the reduction described above, the depth of the external thread at the middle portion 83 is for the hexagon socket 86 so to speak, created space, because the hexagon socket 86 surrounding material of the screw implant 81 both at the top portion 84 and the central portion 83 is approximately equal.

p0018The screw implant 81 may be provided with a coating. The coating consists of a bioactive or biocompatible material. As bioactive material comes particularly hydroxyapatite into consideration. When biocompatible material, it may be titanium (Flame spray) or TiO₂. The areas to be coated are roughened prior to coating, preferably by blasting with corundum. The average roughness of the surfaces to be coated is in the range of R_a2 to 10 .mu.m.

p0019It may be 81 coats the entire screw implant. but it is also conceivable, of the coating, the inner threaded bore 23 and / or the hexagon socket exclude 86th In addition, the entire head portion 84 or an upper portion may be the same uncoated. The uncoated areas of the head section 84 have a smooth surface, in that they are preferably highly polished.