Dental implant system

FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of surgical and prosthetic tools and equipment and more particularly, to a dental implant which incorporates a dental implant with a notched cavity.

BACKGROUND OF THE INVENTION

[0002] The prior art related to the field of dental implants includes various examples of denial implants and insertion tools.

[0003] A typical dental implant according to the prior art includes an external thread which is driven into the bone and an internal thread which accepts an insertion tool. In the past, the insertion tool was screwed into the implant, the implant was screwed into the bone, the insertion tool was unscrewed from the implant and discarded. This process is inherently time consuming and, therefore, disadvantageous.

[0004] Another disadvantage of this type of conventional dental insert is related to the process of unscrewing the dental implant from the insertion tool after the implant has been inserted into the bone. The process of unscrewing the insert is disadvantageous because the process inherently tends to loosen the contact between the insert and the bone.

[0005] Another example of prior art dental inserts is shown in U.S. Pat. No. 4,960,381 issued to Gerald A. Niznick for a Screw-Type Dental Implant Anchor. The Niznick patent shows a screw-type dental implant anchor which includes an externally threaded body portion which includes an internal structure for engaging an insertion tool. The top portion of the implant anchor is open and in registry with an internally-threaded portion. The top portion of the anchor forms a head portion which includes a hex-shaped cavity in its inner wall surfaces for receiving a hex wrench. The internal hex-shaped configuration is intended to allow the insertion of the anchor in the jawbone of a patient using an Allen-type wrench.

[0006] One of the significant disadvantages of the Niznick device is related to the arrangement of the hex-shaped cavity which is positioned directly above the internally threaded portion. As shown and described in the Niznick patent, the smaller distance across the hex-shaped cavity is greater than the external diameter of the internal threads. This configuration creates stress concentrations which results in high stress lines along the hex corners. This problem has resulted in numerous implant fractures.

[0007] Another example of prior art dental inserts is shown in U.S. Pat. No. 6,464,500 to Don D. Popovic for a Dental Implant and Abutment System. The Popovic patent showed a screw-type dental implant anchor which includes an externally threaded body portion which includes an internal structure for engaging an insertion tool. The top portion of the implant anchor includes an internally threaded portion. A hex-shaped cavity is located below the internally threaded portion for the purpose of receiving a hex wrench. As in the Niznick patent previously described, the hex-shaped cavity is intended to facilitate the insertion of the anchor in the jawbone of a patient using an Allen-type wrench. As a result of the location of the hex-shaped cavity below the internally threaded portion, the distance between corners of the hex-shaped cavity is smaller than the internally threaded portion.

[0008] The hex-shaped cavity is therefore so small that at normal insertion torques, there is the distinct possibility of damage to the insertion tool and damage to the insert. This is especially true in the event that the insert binds prematurely in hard bone. This is caused by the required relationship between the internal threads and the hex-shaped cavity. The largest thread normally used has a diameter of about 1.5 millimeters, mm. The distance between the corners of the hex has to be smaller than 1.5 mm, otherwise the insertion tool would not clear the internal threads.

[0009] As a result, neither the configuration of the Niznick device with the hex-shaped cavity above the internally threaded portion nor the Popovic configuration with the hex-shaped cavity below the internally threaded portion provides a satisfactory dental implant.

[0010] Another example of a prior art dental implant is shown in U.S. Design Pat. No. D446,859 issued to Steven M. Hurson for a Multi-Lobed Dental Implant. The Hurson patent shows a screw-type dental implant which includes an externally threaded body portion and an internal cavity for engaging an insertion tool. The Hurson device is generally similar to the Niznick device and the top portion of the implant is open and in registry with an internally threaded portion. The top portion of the implant includes a multi-lobed cavity. In a manner similar to the Niznick device, the multi-lobed cavity extends beyond the external or maximum diameter of the internal threads. As explained in connection with the Niznick device, this configuration creates stress-concentrations where there are discontinuities in the cross-section, such as at the corners of the lobes. As explained previously, these stress concentrations can lead to loss of structural integrity of the implant. These problems are increased when there is an attempt to manufacture the Hurson or the Niznick devices in the relatively narrow configurations which are required for narrow edentulous areas.

[0011] An example of the problems associated with prior art implants is described in an article titled “Ridge Augmentation for Immediate Postextractive Implants: Eight Year Retrospective Study” by A. Ashman, DDS, J. Lo Pinto, DDS, and J. Rosenlicht, DMD, in <i>Practical Periodontics and Aesthetic Dentistry, </i>Vol. 7, No. 2, March 1995, page 89. The article shows an insert with a hex-shaped cavity cut in the internal thread, in which the internal thread was stripped by the insertion tool during surgical placement. This problem resulted in a need to cut a new thread into the implant.

[0012] Despite the developments of the prior art, there remains a need for a dental implant which can be installed in a safe and reliable manner.

OBJECTS AND SUMMARY OF THE INVENTION

[0013] It is an object of the present invention to provide a dental implant system which includes a dental implant having a notched cavity and a complimentary shaped insertion tool.

[0014] Another object of the present invention is to provide a dental implant system which includes a threaded cavity which can accept either a threaded fastener or a multi-lobed insertion tool.

[0015] Another object of the present invention is to provide a dental implant system which can be manufactured in relatively narrow configurations and which can be placed in very narrow edentulous areas.

[0016] Another object of the present invention to provide a dental implant which can accept an insertion tool with a friction fit.

[0017] Another object,of the present invention is to provide a dental implant which does not require a screw-type of connection with the insertion tool.

[0018] Another object of the present invention is to provide a dental implant which can be quickly installed on an insertion tool.

[0019] Another object of the present invention is to provide a dental implant which demonstrates relatively great resistance to fracture thereby providing a safe and reliable installation.

[0020] Another object of the present invention is to provide a dental implant which can be quickly and easily removed from an insertion tool after the dental implant is inserted into the bone.

[0021] Another object of the present invention is to provide a dental implant which does not require being unscrewed from the insertion tool after the dental implant has been inserted into the bone.

[0022] Yet another object of the present invention is to provide a dental implant which facilitates secure transportation from the dental implant pack to the surgical field.

[0023] Other objects and advantages of the invention will become evident hereinafter.

[0024] In accordance with the present invention, there is provided a dental implant system which incorporates a dental implant which includes an external thread for threading into the bone. The implant includes an internally threaded portion which accepts a post for the attachment of a prosthesis. A key feature of the invention is a notched cavity which is cut through the internally threaded portion. The notched cavity preferably has a configuration in the shape of a circular array with six grooves with the external diameter of the grooves approximately equal to the major diameter of the threads and the internal diameter of the grooves approximately equal to the minor diameter of the threads. In addition, the dental insert includes an internally tapered portion. The internally tapered portion and the notched cavity accept an insertion tool of complementary shape.

[0025] The insertion tool can be inserted into the dental implant and then used to transport the dental implant to the surgical field in a safe and convenient manner. The insertion tool can then be used to insert the dental implant into the bone. After the insertion process has been completed, the insertion tool is simply withdrawn from the implant without a need for unscrewing or other cumbersome techniques.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other important objects and advantages of the invention will be apparent from the following detailed description of the invention taken in connection with the accompanying drawings in which:

[0027]FIG. 1 is an overall perspective view of a dental implant made according to the present invention,

[0028]FIG. 2 is another overall perspective view of the dental implant of FIG. 1;

[0029]FIG. 3 is a side elevation view taken along the line <b>3</b>-<b>3</b> of FIG. 1;

[0030]FIG. 4 is an end view along the line <b>4</b>-<b>4</b> of FIG. 3;

[0031]FIG. 5 is a cross-sectional view taken along the line <b>5</b>-<b>5</b> of FIG. 1;

[0032]FIG. 6 is an end view taken along the line <b>6</b>-<b>6</b> of FIG. 3;

[0033]FIG. 7 is an overall perspective view of an abutment for use with the dental implant of FIG. 1;

[0034]FIG. 8 is a side elevation view of the abutment of FIG. 7;

[0035]FIG. 9 shows the start of the insertion of the abutment of FIG. 8 into the dental implant of FIG. 1;

[0036]FIG. 10 shows the abutment inserted into the dental implant;

[0037]FIG. 11 shows an overall perspective view of an insertion tool for use with the dental implant of FIG. 1;

[0038]FIG. 12 is a cross-sectional view showing the insertion tool of FIG. 11 inserted into the dental implant of FIG. 1;

[0039]FIG. 13 is a side view partially in section showing an alternative embodiment of the dental implant of FIG. 1; and

[0040]FIG. 14 is an end view of the dental implant of FIG. 13.

[0041]FIG. 15 is an end view generally similar to FIG. 6 showing another embodiment of the dental implant of FIG. 1;

[0042]FIG. 16 is an end view generally similar to FIG. 6 showing yet another embodiment of the dental implant of FIG. 1; and

[0043]FIG. 17 is a cross-sectional view of an alternative embodiment of the insertion tool shown in FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

[0044] With reference to the drawings, in which like reference numbers designate like or corresponding parts throughout, there is shown in FIGS. 1-12 a dental implant system <b>10</b> made in accordance with the present invention, which includes a dental implant <b>12</b> which has a body portion which has a self-tapping threaded exterior surface <b>16</b>. The end <b>18</b> of the body portion <b>14</b> has a full radius resulting in a convex configuration. The dental implant system <b>10</b> also includes an insertion tool <b>20</b> which will be described presently.

[0045] The following dimensions are by way of example only and are not to be considered as limitations on the present invention. The overall length of the dental implant <b>12</b> is generally between 5 mm and 20 mm. The outside diameter of the dental implant <b>12</b> is generally between 3 mm and 7 mm. The threaded exterior surface <b>16</b> is used to anchor the dental implant <b>12</b> into the patient's bone. The dental implant <b>12</b> includes an internally threaded portion <b>21</b>. The function of the internal thread <b>22</b> is to facilitate attachment of a cover screw and prosthetic components or an abutment <b>24</b>. The internal thread <b>22</b> typically has a major diameter which ranges between 1.3 mm and 2.0 mm.

[0046] The upper portion <b>26</b> of the body portion <b>14</b> is unthreaded and is outwardly flared. The radius of curvature of the surface <b>28</b> of the outwardly flared portion <b>26</b> as shown by the radius “R” in FIG. 3. has a preferred radius in the order of approximately 0.5 inches. The end <b>30</b> of the body portion <b>14</b> has an inwardly tapered cavity <b>32</b> which leads from the end <b>30</b> of the body portion <b>14</b> to an internally threaded portion <b>22</b> which extends inwardly from a plane <b>34</b> at the base <b>36</b> of the tapered cavity <b>32</b>.

[0047] The end <b>30</b> of the body portion <b>14</b> has a chamfered portion <b>38</b> which has a preferred angle in the order of 45 degrees.

[0048] A notched or grooved cavity <b>40</b> which is a key feature of the present invention, extends inwardly from the plane <b>34</b> at the base <b>36</b> of the tapered cavity <b>32</b>. As is best shown in FIGS. 3-6, the grooved cavity <b>40</b> extends past the end <b>42</b> of the internally threaded portion <b>22</b>. The grooved cavity <b>40</b> as shown in FIG. 6 has six grooves <b>44</b>, <b>46</b>, <b>48</b>, <b>50</b>, <b>52</b>, <b>54</b> with the depth of the grooves extending to a point approximately equal to the major diameter of the threaded portion <b>22</b> and with the minor diameter of the groove array approximately equal to the minor diameter of the threaded portion <b>22</b>. Wall portions <b>56</b>, <b>58</b>, <b>60</b>, <b>62</b>, <b>64</b>, <b>66</b> defining the grooves are generally curved.

[0049] The curved wall portions <b>56</b>, <b>58</b>,.<b>60</b>, <b>62</b>, <b>64</b>, <b>66</b> form an important advantage of the present invention <b>10</b>. Prior art cavities used for transmitting torque have generally utilized a hexagonal shape. In a hexagon, the distances between the opposing flat portions of a hexagon are nearly equal to the distances between the opposing corner portions of the hexagon. There is thus a relatively small ratio between the dimensions between the corners of the hexagon and the flat portions of the hexagon.

[0050] The relatively small ratio between the dimensions between the corners of a hexagon and the flat portions of a hexagon results in a tendency to strip or fail especially when a hexagonal cavity is formed in the relatively small sizes required for dental inserts.

[0051] In the grooved or notched cavity <b>40</b>, according to the present invention, which is formed by the concave curved wall portions <b>56</b>, <b>58</b>, <b>60</b>, <b>62</b>, <b>64</b>, <b>66</b>, there is a relatively large ratio between the larger dimension as measured between the corners of the grooves typically indicted by the numerals <b>67</b>, <b>69</b> and the relatively smaller dimension as measured between the closest points of the curved wall portions typically indicated by the numerals <b>68</b>, <b>70</b>. The reference numerals <b>68</b>, <b>70</b> thus indicate the narrowest portion of the grooved cavity <b>40</b>. This relatively large ratio enables the cavity <b>40</b> to be cut into the threads <b>22</b> without the danger of weakening the threads.

[0052] As indicated above in FIG. 6, the grooves or notches <b>44</b>, <b>46</b>, <b>48</b>, <b>50</b>, <b>52</b>, <b>54</b> are formed to a depth which approximates the major diameter of the internal thread <b>22</b> as indicated by the broken lines <b>72</b>.

[0053] As shown in FIGS. 3-6, the end <b>74</b> of the grooved cavity <b>40</b> extends past the inner end <b>42</b> of the internally threaded portion <b>22</b>. Alternatively, the end <b>74</b> of the grooved cavity <b>40</b> may end at the inner: end <b>42</b> of the threaded portion <b>22</b>. In another alternative embodiment, the end <b>74</b> of the grooved cavity <b>40</b> may end at an intermediate portion of the threaded portion <b>22</b> as denoted by the reference numeral <b>78</b> in FIG. 5.

[0054] As is shown in FIGS. 3-6, the internally notched or grooved cavity <b>40</b> is cut through the internally threaded portion <b>22</b> and can easily accept the grooved portion <b>80</b> of the installation tool <b>20</b> which is shown in FIGS. 11 and 12. The grooved portion <b>80</b> of the installation tool <b>20</b> compliments the grooved cavity <b>40</b> of the dental implant <b>10</b>. The insertion tool <b>20</b> is typically made of instrument grade stainless steel.

[0055] After the dental implant <b>12</b> has been inserted into the patient's bone using the installation tool <b>20</b>, the installation tool <b>20</b> is withdrawn. A screw type of abutment <b>24</b> which is shown in FIGS. 7 and 8 is installed into the dental implant <b>12</b> as is shown in FIGS. 9 and 10. The threaded portion <b>82</b> of the abutment <b>24</b> engages the internal thread <b>22</b>. As is best shown in FIG. 10, the tapered cavity <b>32</b> of the dental implant <b>10</b> compliments the tapered portion <b>84</b> of the abutment <b>82</b> resulting in a secure fit. The outwardly flared portion <b>26</b> of the dental implant <b>12</b> and the chamfered portion <b>38</b> cooperate with the abutment <b>82</b> to provide an efficient transfer of the dental forces with a minimum size and weight structure.

[0056] One of the key advantages of the dental implant <b>12</b> of the present invention is related to the relatively great strength of the dental implant <b>12</b> as compared with prior art devices. Torque testing of the dental implant <b>12</b> of the present invention and the hex cavity device shown in the Popovic patent U.S. Pat. No. 6,464,500 is summarized in Table 1. <tables id="TABLE-US-00001" num="1"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="1"><colspec colname="1" colwidth="217PT" align="center" /><thead><row><entry namest="1" nameend="1" align="center">TABLE 1</entry></row></thead><tbody valign="top"><row><entry /></row><row><entry namest="1" nameend="1" align="center" rowsep="1" /></row><row><entry>COMPARATIVE RESISTENCE TO TORQUE</entry></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="3"><colspec colname="1" colwidth="77PT" align="center" /><colspec colname="2" colwidth="70PT" align="center" /><colspec colname="3" colwidth="70PT" align="center" /><tbody valign="top"><row><entry /><entry>APPLIED TORQUE</entry><entry /></row><row><entry>UNIT</entry><entry>(Newton Centimeters)</entry><entry>RESULTS</entry></row><row><entry namest="1" nameend="3" align="center" rowsep="1" /></row><row><entry>Prior art</entry><entry>100</entry><entry>Fracture of</entry></row><row><entry>Hex-cavity device</entry><entry /><entry>the insertion</entry></row><row><entry>Popovic Patent</entry><entry /><entry>tool</entry></row><row><entry>U.S. Pat. 6,464,500</entry></row><row><entry>Dental Implant</entry><entry>150-200</entry><entry>No fracture or</entry></row><row><entry>according to the</entry><entry /><entry>weakening</entry></row><row><entry>present invention</entry></row><row><entry namest="1" nameend="3" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>

[0057] Typical insertion torque is usually 50-130 Ncm. However, this torque can reach higher values if the implant binds prematurely in hard bone.

[0058] The significantly increased resistance to torque experienced during the installation into the bone of a patent by the dental implant <b>12</b> according to the present invention results in a significant increase in the safety and reliability of the installation process.

[0059] The dental implant <b>12</b> may be made of any implantable metal or ceramic material including commercially pure titanium.

[0060] A preferred material for the dental implant <b>12</b> according to the present invention has been found to be 6AL-4V-EL1 titantium.

[0061]FIGS. 13-14 show an alternate embodiment <b>100</b> of the present invention which incorporates an external hex surface <b>102</b> at the upper end <b>104</b> of the implant. The body <b>106</b> of the implant <b>100</b> includes an outside surface <b>108</b> with a thread pattern <b>110</b> for anchoring the implant <b>100</b> into bone and an internal thread <b>112</b> which is similar to the internal thread <b>22</b> previously described. In the embodiment <b>100</b> shown in FIGS. 13-14, the tapered portion <b>32</b> previously described has been eliminated and the grooved cavity <b>114</b>, which is similar to the grooved cavity <b>40</b> previously described, extends to the top surface <b>116</b> of the implant <b>100</b>. The end <b>118</b> of the implant <b>100</b> is flat.

[0062] In the alternative embodiment of the invention <b>200</b> shown in FIG. 15, the ends <b>202</b>, <b>204</b>, <b>206</b>, <b>208</b> of the grooves <b>210</b>, <b>212</b>, <b>214</b>, <b>216</b> extend beyond the major diameter of the internal thread <b>224</b> which is shown in broken lines <b>218</b>. Alternatively, the grooves <b>210</b>, <b>212</b>, <b>214</b>, <b>216</b> may extend to points <b>230</b>, <b>232</b> indicated in FIG. 15 which define a diameter which is smaller than the major diameter <b>218</b> of the internal thread <b>224</b>. As described previously, the grooves <b>210</b>, <b>212</b>, <b>214</b>, <b>216</b> are, in part, defined by curved portions <b>226</b>, <b>228</b>, <b>230</b>, <b>232</b>.

[0063] The alternative embodiment of the invention <b>200</b> shown in FIG. 15 has four (4) grooves <b>210</b>, <b>212</b>, <b>214</b>, <b>216</b> or notches, while the alternative embodiment <b>300</b> shown in FIG. 16 has eight (8) grooves <b>302</b>, <b>304</b>, <b>306</b>, <b>308</b>, <b>310</b>, <b>312</b>, <b>314</b>, <b>316</b> or notches. The number of grooves or notches may have a preferred range between two (2) and eight (8).

[0064] The construction of the grooves <b>302</b>, <b>304</b>, <b>306</b>, <b>308</b>, <b>310</b><b>312</b>, <b>314</b>, <b>316</b> is generally similar to the construction of the grooves previously described in connection with FIGS. 6 and 15. With the exception of the grooved cavities <b>234</b>, <b>318</b>, the overall construction of the embodiments <b>200</b> and <b>300</b> shown in FIGS. 15 and 16 is generally similar to the construction of the insert <b>12</b> shown in FIGS. 1-6. The ends <b>202</b>, <b>204</b>, <b>206</b>, <b>208</b> of each of the grooves <b>210</b>, <b>212</b>, <b>214</b>, <b>216</b> in FIG. 15 are shown as convexly curved. This construction is typical of each of the grooves in the embodiments <b>12</b>, <b>100</b>, <b>288</b>, <b>300</b> shown in FIGS. 1-6, <b>13</b>, and <b>16</b>.

[0065] In the insertion tool <b>20</b> shown in FIGS. 11 and 12, the grooves <b>90</b> are generally parallel to a central axis. In the alternative embodiment of the insertion tool <b>400</b> shown in FIG. 17, the walls <b>404</b>, <b>402</b>, which define the grooves <b>406</b>, <b>408</b>, each include a tapered portion <b>410</b> which facilitates a friction fit with the dental inserts <b>12</b>, <b>100</b>, <b>200</b>, <b>300</b>. The tapered portion <b>410</b> is defined in part by an angular portion designated by the angle “A” in FIG. 7.

[0066] The foregoing specific embodiments of the present invention as set forth in: the specification herein are for illustrative purposes only. Various deviations and modifications may be made within the spirit and scope of the invention without departing from the main theme thereof.