Patent Publication Number: US-2010129772-A1

Title: Captive thread dental implant apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to a dental implant apparatuses, and more specifically relates to captive thread dental implant apparatuses. 
     DESCRIPTION OF BACKGROUND INFORMATION 
     Without limiting the scope of the present invention, its background will be described in relation to a captive thread dental anchor apparatus as an example. 
     Various methods and structures for anchoring appliances in the oral cavity are known in the art. For example, U.S. Pat. No. 4,540,367 issued to Sulc (“the &#39;367 patent”) describes a multi-piece apparatus having a female member which attaches to a surface of a tooth adjacent to an apparatus anchoring site. Also shown in the &#39;367 patent is an oral appliance containing a male member which attaches to the female member. The apparatus and method described by the &#39;367 patent, although particularly useful for attaching to a dental surface adjacent to a desired anchoring site, is not optimal for all anchoring requirements. 
     Another anchoring method and apparatus is described by U.S. Pat. No. 5,749,732 issued to Sendax (“the &#39;732 patent”). The apparatus described by the &#39;732 patent comprises a threaded anchor post having a square male upper extension using a wrench having a square socket, the threaded portion is rotated to attain threaded engagement with a bone. After the threaded portion has penetrated the bone to a suitable depth, the square male upper extension remains above the gum. The threaded post portion has a lower threaded portion and an upper threaded portion separated by an unthreaded land. The &#39;732 patent describes the unthreaded land as functioning to assist bone growth engagement thereby securing the anchor from unthreading. The square upper extension mates with and is secured by adhesive to an oral appliance having a corresponding square receptacle. Additionally, there are commercially available anchors similar to the device described in the &#39;732 patent but without the unthreaded land. 
     The apparatus and method described by the &#39;732 patent and the similarly structured commercial products have shortcomings. One is that the upper extension in its cooperative fit with a dental appliance offers little, if any, adjustment after insertion. More particularly, the orientation of the upper extension is fixed by the rotational angle and insertion angle at the threaded portion. The orientation of this receptacle in the dental appliance which is shaped to correspond to the upper extension is also fixed relative to the appliance. However, after the threaded portion is screwed into the recipient&#39;s bone, changing its angle requires removal and reinsertion. After a period of time, bone growth fixes the rotational position as well. Therefore, after insertion of the threaded anchor, the angle and position of the dental appliance is substantially fixed. 
     Various methods and apparatie for adjusting the angle of a dental appliance anchor are also know. For example U.S. Pat. No. 4,713,004 issued to Linkow, et al. (“the &#39;004 patent”) discloses an implant placed in the bone and rotated into a proper orientation. The &#39;004 patent shows a wedge shaped collar having an angle upper surface which is described as positioned to coincide with the angle of the shaft so that the free end of the shaft extends perpendicularly from the angled surface. The &#39;004 patent further shows a prosthetic tooth anchor threaded onto the free end of the shaft to secure the collar in a fixed orientation. The &#39;004 patent apparatus and method, although directed to an alignment issue, is relatively complex and may have insufficient structural rigidity for some applications. 
     In another example, U.S. Pat. No. 5,195,891 also issued to Sulc (“the &#39;891 patent”) discloses a three piece adjustable dental implant system. The three piece dental implant system includes an implant that is inserted into the bone of a patient and has a threaded cavity which accepts a threaded shaft base. Once the threaded shaft base is threaded into the threaded cavity of the implant, no further rotation of the base is allowed. The upper part of the base includes a cavity which has an interference fit with and angled support thereby providing a three piece adjustable dental implant system. 
     In yet another example, U.S. Pat. No. 6,695,616 issued to Ellison (“the &#39;616 patent”) discloses a two piece apparatus and method for anchoring a dental appliance. This two piece dental appliance includes an upper removal support anchor which snaps into by an interference fit into an anchor implant member which is screwed into the bone of a patient. The upper removal support member may be an angled member such that it accepts a dental prosthesis and fits a desired angle. The anchored implant member includes an upper receptacle and an undercut which receives the upper removable support member and where adhesives may be applied such that the interference fit allows rotation of the upper removal support member prior to setting of the adhesive. 
     SUMMARY OF THE INVENTION 
     The above described problems are solved and technical advances achieved by the present dental anchor apparatus. In one embodiment the present captive thread dental implant apparatus includes a removable support member having a first receptacle on one end and a first threaded shank portion on the other end, the removable support member having a non-threaded shank portion extending between the first threaded shank portion and the first receptacle; and an anchor implant member having a lower body portion on one end and a second receptacle on the other end for receiving the first threaded shank portion of the removable support member, the second receptacle having a second threaded portion located within the second receptacle for engaging the first threaded shank portion, the non-threaded shank portion located adjacent to the second threaded shank portion when the removable support member is joined with the anchor implant member. In one aspect the non-threaded shank portion has a diameter that is less than the diameter of second threaded portion. In another aspect, the second threaded shank portion is disengaged and in a longitudinally captive thread arrangement from the first threaded shank portion when the removable support member is joined with the anchor implant member. 
     In yet another aspect, the removable support member is freely rotatable relative to the anchor implant member when the removable support member is joined with the anchor implant member. Preferably, the removable support member further includes an abutment portion located between the first receptacle and the first threaded portion and extending laterally from the removable support member for abutting against the second receptacle to provide a stop between removable support member and the second receptacle. Additionally, the abutment portion may have a diameter that is one of greater or equal to the outer diameter of the second receptacle. Further, the lower body portion may include a longitudinally extending threaded portion for engaging the bone of a patient for anchoring the anchor implant member to a bone of a patient. 
     In another embodiment, the present captive thread dental implant apparatus includes a removable support member having a first receptacle on one end and a first threaded shank portion on the other end, the removable support member having a non-threaded shank portion extending between the first threaded shank portion and the first receptacle, wherein the first receptacle provides a female interference fit for releasably engaging a male end of a dental prosthesis; and an anchor implant member having a lower body portion on one end and a second receptacle on the other end for receiving the first threaded shank portion of the removable support member, the second receptacle having a second threaded portion located within the second receptacle for engaging the first threaded shank portion, the non-threaded shank portion located adjacent to the second threaded shank portion when the removable support member is joined with the anchor implant member. 
     In one aspect, the non-threaded shank portion may have a diameter that is less than the diameter of second threaded portion. In another aspect, the second threaded shank portion may be disengaged and in a longitudinally captive thread arrangement from the first threaded shank portion when the removable support member is joined with the anchor implant member. Preferably, the female interference fit may include a divergent-convergent-divergent cross-sectional diameter. Additionally, the removable support member may include an abutment portion located between the first receptacle and the first threaded portion and extending laterally from the removable support member for abutting against the second receptacle to provide a stop between removable support member and the second receptacle. Also, the abutment portion may have a diameter that is one of greater or equal to the outer diameter of the second receptacle. 
     In another aspect, the lower body portion may further include a longitudinally extending threaded portion for engaging the bone of a patient for anchoring the anchor implant member to a bone of a patient. In yet another aspect, the first receptacle may further include at least one aperture disposed through the first receptacle. Additionally, the removable support member may include a cavity extending longitudinally from the first threaded shank portion towards the first receptacle. 
     In yet another embodiment, the present captive thread dental implant apparatus may include a removable support member having a first receptacle on one end and a first threaded shank portion on the other end, the removable support member having a non-threaded shank portion extending between the first threaded shank portion and the first receptacle, wherein the first receptacle is adapted to releasably engage a male end of a dental prosthesis; and an anchor implant member having a lower body portion on one end and a second receptacle on the other end for receiving the first threaded shank portion of the removable support member, the second receptacle having a second threaded portion located within the second receptacle for engaging the first threaded shank portion, the non-threaded shank portion located adjacent to the second threaded shank portion when the removable support member is joined with the anchor implant member. 
     In one aspect, the non-threaded shank portion may have a diameter that is less than the diameter of second threaded portion. In another aspect, the lower body portion may further include a longitudinally extending threaded portion for engaging the bone of a patient for anchoring the anchor implant member to the bone of the patient. Preferably, the second threaded shank portion may be disengaged and in a longitudinally captive thread arrangement from the first threaded shank portion when the removable support member is joined with the anchor implant member, wherein the removable support member is freely rotatable relative to the anchor implant member when the removable support member is joined with the anchor implant member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which: 
         FIG. 1  illustrates a perspective exploded view of a dental anchor apparatus according to an embodiment of the present invention; 
         FIG. 2  illustrates a perspective view of a joined dental anchor apparatus of  FIG. 1  according to an embodiment of the present invention; 
         FIG. 3  illustrates another exploded perspective view of the dental anchor apparatus of  FIG. 1  according to an embodiment of the present invention; 
         FIG. 4  illustrates a exploded cross-section view of the dental anchor apparatus of  FIG. 1  according to an embodiment of the present invention; and 
         FIG. 5  illustrates a cross-section view of the joined dental anchor apparatus of  FIG. 1  according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable event of concepts which can be embodied in a wide variety of specific context. The specific embodiments discussed herein are merely illustrated of specific ways to make and use the invention and do not delimit the scope of the present invention. 
     In the following description of the representative embodiments of the invention, directional terms such as “above,” “below,” “upper,” “lower,” etc. are used for convenience in referring to the accompanying drawings. In general, “above,” “upper,” and “upward” and similar terms refer to a direction with respect to the dental anchor apparatus orientated in a generally upward fashion such that a dental prosthesis would snap onto the top of the dental anchor apparatus. Additionally, terms such as “below,” “lower,” and “downward” and similar terms refer to a direction away or opposite of the upward direction. In another embodiment these relative terms may be reversed such that the dental anchor implant apparatus may be in the opposite direction as discussed. For example, if the dental anchor apparatus were to be used in a top row or teeth of a recipient or patient, then the relative direction terms would be the opposite than those used for the dental anchor apparatus being used on the bottom row of teeth of the recipient or patient. 
     Referring initially to  FIGS. 1-3 , an embodiment of a captive thread dental anchor apparatus (“dental anchor apparatus”) is illustrated and generally designated  100 . Dental anchor apparatus  100  may include a removable support member  102  and an anchor implant member  104 . These members may be joined as shown in the figures. Removable support member  102  may include an upper body portion  108 , which may define or form a receptacle  106  for receiving a dental prosthesis, as further described herein. 
     Removable support member  102  may further include an abutment portion  110 , which has a greater diameter then the upper body portion  108 , in one example. In this manner upper body portion  108  extends down to abutment portion  110  of removable support member  102 . Extending from abutment portion  110  downward is a non-threaded shank portion  112 , which generally has a diameter less than abutment portion  110 . In one example, abutment portion  110  and non-threaded shank portion  112  are also generally cylindrical in shape or form. In one aspect, the non-threaded shank portion  112  extends down and terminates in threaded shank portion  114  which contains one or more or plurality of threads  126  as is commonly known in the art. 
     Anchor implant member  104  may also be substantially cylindrically shaped member that includes a receptacle  116  for receiving threads  126 , threaded shank portion  114 , and non-threaded shank portion  112 . In one aspect, receptacle  116  may be formed or shaped by a receptacle base portion  118 , which further is substantially cylindrically shaped or formed. As shown in  FIG. 2 , abutment portion  110  abuts against receptacle base portion  118  when upper body portion  108  is inserted into and joined with anchor implant member  104 . 
     Extending from receptacle base portion  118  downward is upper body portion  120  of anchor implant member  104 . As shown, upper body portion  120  may have a tapering shape or form as it transitions from receptacle base portion  118  to a lower body portion  122 . Lower body portion  122  is shown without threads or threaded portion in one embodiment. In another embodiment, lower body portion  122  may be a threaded portion as depicted by U.S. Pat. No. 6,695,616 issued to Ellison, which is hereby incorporated by reference. In this embodiment, lower body portion  122  includes a threaded portion for threading into the bone of a recipient or patient. 
     Referring now to  FIG. 3 , removable support member  102  can be seen with a cavity  304  extending from a bottom surface  302  of removable support member  102  upward through the interior portion of removable support member  102 . Generally, cavity  304  extends inward through removable support member  102  substantially along it longitudinal axis, for example. Cavity  304  may extend inward from bottom surface  302  to any desired depth within the longitudinal axis generally of the removal support member  102 , for example. 
     Although removable support member  102  is generally shown as a straight or linear cylindrical or substantially cylindrical shaped object, removable support member  102  may further include an angled support member or be an angled shaped former object as disclosed in U.S. Pat. No. 6,695,616 issued to Ellison, which is hereby incorporated by reference. In one embodiment, removable support member  102  may have an upper body portion  108 , which has a longitudinal axis that is angled from the longitudinal axis of abutment portion  110 , nonthreaded shank portion  112 , and threaded shank portion  114 . This is so to accept a dental prosthesis that provides a different angle within the oral cavity of a patient. Thus, although a substantially linear removable support member  102  is shown, dental anchor apparatus  100  further includes embodiments where the removable member  102  has an angled upper body portion  108  relative to the lower portion of removable support member  102 . 
     Removable support member  102  and anchor implant member  104  may be a metal structure and formed of a titanium-aluminum-vanadium alloy or any other metal, composition, or alloy as desired. In another embodiment, removable support member  102  may be made from a different metal, composition, or alloy of materials than anchor implant member  104 . Additionally, the general lateral cross-section shape of removable support member  102  and anchor implant member  104  may be other than substantially cylindrical, such as a polygonal shape, such as hexagonal and pentagonal, for example. Additionally, anchor implant member  104  may have flat surfaces on the upper body portion  120  for accepting a wrench or other tool for inserting the anchor implant member  104  into the bone of a recipient or patient and applying torque, such that the anchor implant member  104  is located substantially below the gum line of a jaw bone (not shown) with the lower body portion  122  threaded into or inserted into the underlying bone of the patient. 
     Referring now to  FIGS. 4 and 5 , an exploded and non-exploded view of dental anchor apparatus  100  is shown. These cross-section views show abutment portion  110  having a wider diameter than the non-threaded shank portion  112 , such that the non-threaded shank portion  112  extends a distance between abutment portion  110  and threads  126  of threaded shank portion  114 . The width (w 1 ) of the diameter of non-threaded shank portion  112  has a smaller diameter than the threaded shank portion  114  which is shown having a diameter of (w 2 ), for example. 
     Anchor implant member  104  is shown having receptacle  116  with a general diameter of the opening of receptacle  116  being shown as (w 3 ). The diameter (w 3 ) of receptacle  116  is greater than the diameter of the threaded portion  412  of anchor implant member  104 , threaded portion  412  located substantially within receptacle  116  of anchor implant member  104 . Likewise, a lower portion of the receptacle  116  noted as lower portion  416  has a greater diameter (w 4 ) than threaded portion  412  of anchor implant member  104 . In one embodiment, as removable support member  102  is joined or inserted into anchor implant member  104 , the threads  126  of removable support member  102  slide down within and through diameter (w 3 ) of receptacle  116 . As threads  126  slide down into receptacle  116 , they stop and engage threaded portion  412  of receptacle  116 . At this point, removable support member  102  may be rotated such that threads  126  engage threaded portion  412  of receptacle  116 . 
     As removable support member  102  is rotated further, threads  126  engage further threaded portion  412  until they clear or fully disposed all the way through threaded portion  412  and are located in lower portion  416  of anchor implant member  104 , as best illustrated as in  FIG. 5 . Continuing now with  FIG. 5 , removable support member  102  can be seen fully joined with anchor implant member  104 ; threads  126  having a diameter (w 2 ) are substantially wider than the threaded shank portion  114  of removable support member  102 . In this way, removable support member  102  is free to continue to rotate within the receptacle  116  of anchor implant member  104  while being retained by the threaded shank portion  114  of lower portion  416  and threaded portion  412  of anchor implant member  104 . Referring back to  FIG. 4 , receptacle  116  may further include a tapered portion  414  that transitions from threaded portion  412  to lower portion  416  of anchor implant member  104 . The tapered portion  414  may have a gradient radial diameter transitioning from threaded portion  412  to lower portion  416 , for example. In one embodiment, the tapered portion  414  further retains threads  126  of removable support member  102  such that the removable support member  102  is captive to anchor implant member  104  and may be rotated freely for further alignment of removable support member  102  within the oral cavity of a patient while being retained or joined longitudinally. 
     As shown, non-threaded shank portion  112  has a length noted as “L 2 ” that may be slightly longer than the length “L 1 ” of the receptacle base portion  118  and upper body portion  120  such that the non-threaded shank portion  112  is adjacent to and rotates against the threaded portion  412  of anchor implant member  104 , for example. Additionally, a space  502  may be provided between the removable support member  102  and the anchor implant member  104  and also further between non-threaded shank portion  112  and threaded portion  412  of anchor implant member  104 . Further, some space or available volume within the receptacle  116  may be provided near or at the bottom surface  302  and the interior bottom of receptacle  116  of implant anchor member  104  for holding an adhesive. By the engagement of threads  126  of removable support member  102  against tapered portion  414  of anchor implant member  104 , it can be seen that removable support member  102  is held captive and may be freely rotated within the receptacle  116  for further positioning and alignment as desired. This captive thread arrangement allows a medical professional to rotate removable support member  102  relative to anchor implant member  104  such as to find a desirable position among the teeth in the oral cavity of a patient prior to joining removable support member  102  with anchor implant member  104  with an adhesive, for example. In this regard, a dental prosthesis may be then inserted into receptacle  106  of removable support member  102  for further alignment and positioning as desired prior to joining the members with an adhesive. 
     By removable support member  102  being freely rotatable relative to anchor implant member  104 , different removable support members  102  may be tried and quickly inserted and removed from anchor implant member  104  until the desired size and shape and angle of removable support member  102  can be found. Additionally, the captive thread arrangement between a removable support member  102  and anchor implant member  104  provides for a secured longitudinal restrained relationship between these two members, thus providing further longitudinal rigidity to removable support member  102  relative to anchor implant member  104  during fitting and adhesion of a dental prosthesis. In one embodiment, once the desired removable support member  102  is located and positioned, it may be removed from anchor implant member  104  such that adhesive may be placed within the receptacle  116  of anchor implant member  104 . Then, later inserting removable support member  102  back into receptacle  116  it can be rotated in the captive thread arrangement as described herein, and later set with adhesive that is placed within the receptacle  116  as would be known by those commonly skilled in the art. 
     It will be understood that the example receptacle  116  described above is for purposes of explaining the operation of and providing general guidance in the practicing of this invention. Upon reading this disclosure, other structures for the receptacle  116  to provide for rotation of the removable support member  102  prior to setting of its adhesive, can be readily identified by persons skilled in the art. 
     As described in the &#39;181 and &#39;367 patents, the male extension within a dental prosthesis (not shown) is preferable formed of a plastic material or other type of material having sufficient strength and durability to permit repeated connection and disconnection with the receptacle  106  of removable support member  102 . In addition, the material of the male extension should develop a retaining friction between it and the material of the receptacle  106  to maintain attachment of the male extension and, accordingly, the attachment of the dental prosthesis. Further, the material of the male extension should permit removal and reinsertion of the male cap when desired. This is preferred because the male extension typically absorbs wear during time and chewing forces, and as a result, should be periodically, or may be periodically replaced. An example material for the male extension may be strong nylon, for example. An example replacement technique by which one male cap is removed and replaced by another is described in the Sulc &#39;367 patent. 
     An example method for installing an anchor implant member  104  and removable support member  102  of this invention will be described. First, the installation site, such as a jaw bone, is prepared using established methods within the dental and oral surgery arts. Next, the bone is predrilled using a drill bit diameter and drilling depth selected by one skilled in the relevant arts. The tapered end of the lower body portion  122  of the anchor implant member  104  is then placed into the drilled area, and using a wrench or other tool, is screwed into the bone until the surface of the lower body portion  122  is at the desired height. 
     Next, using an alignment handle such as described in the &#39;181 patent, or by direct visual inspection, an appropriate angle, whether it be linear or angular of the removable support member  102 , is chosen. Typically, these angles may be zero, five, eleven and seventeen degrees, for example. Therefore, in a typical method according to this invention, the dentist or oral surgeon would have an assortment of angled and linear removable support members  102 , for example. 
     The removable support member  102  is inserted into the receptacle  116  such that threads  126  and threaded shank portion  114  are inserted into the receptacle base portion  118  of anchor implant member  104 . As the threads engage the threaded portion  412  of anchor implant member  104 , the removable support member  102  is rotated by the dentist or oral surgeon such that the threads  126  engage the threaded portion  412  of anchor implant member  104 . 
     Upon the engagement of threads  126 , with the threaded portion  412  of anchor implant member  104 , the removable support member  102  is inserted and screwed into the anchor implant member  104  until the threads  126  of the threaded shank portion  114  pass all the way through threaded portion  412  of anchor implant member  104 . Upon the threads  126  clearing the threaded portion  412  of anchor implant member  104 , threads  126  are then captive within the lower portion  416  of anchor implant member  104 , for example. 
     At this point, removable support member  102  is captive within anchor implant member  104  such that it may be rotated to a desirable rotation where the angle or linear part of the receptacle  106  is aligned with the adjacent teeth. A dental prosthesis may then be placed within receptacle  106  so that the dentist and oral surgeon can determine whether the dental prosthesis is correctly aligned relative to its adjacent teeth within the oral cavity of a recipient or patient. Once it is found that the removable support member  102  is the proper and desired removable support member  102  having a desired angular or linear longitudinal axis, it is then removed, or may be removed from anchor implant member  104  by rotating in an opposite direction such that the threads  126  re-engage threaded portion  412  of anchor implant member  104 . The threads  126  then rotate in the opposite direction and unscrew or unthread from the receptacle  116  of anchor implant member  104 . Once the removable support member  102  has been removed from receptacle  116 , an adhesive may be placed within receptacle  116  and then removable support member  102  may then be inserted and rotated as described herein. A desired rotation and location of removable support member  102  is then finalized within anchor implant member  104  prior to adhesive being set in removable support member  102  to anchor implant member  104 . 
     While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications in combinations of illustrative embodiments as well as other embodiments of the invention will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.