Patent Publication Number: US-2021186665-A1

Title: Dental implant with porous ingrowth material

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a non-provisional application based upon U.S. provisional patent application Ser. No. 62/950,396, entitled “DENTAL IMPLANT WITH POROUS INGROWTH MATERIAL”, filed Dec. 19, 2019, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to dental implants and, more particularly, to dental implants incorporating features to encourage stable fixation following implantation. 
     2. Description of the Related Art 
     Dental implants are known that can be used to treat defect regions in a mouth of a patient. Known dental implants include a base portion that is fixated in the mouth before a replacement tooth is mounted to the base portion. Before the replacement tooth can be mounted to the base portion, the base portion must be firmly and stably fixated in the mouth. In many cases, the base portion is fixated in the mouth using, for example, fixation screws that are driven into solid tissue, such as tissue of the jawbone. Not only is this fixation painful for the patient, but such fixation is not always sufficient to hold the dental implant in place, which requires a revision surgery and additional pain and recovery time for the patient. 
     What is needed in the art is a reliable way to treat a defect region in a patient&#39;s mouth. 
     SUMMARY OF THE INVENTION 
     Exemplary embodiments disclosed herein provide dental implants that have porous ingrowth material on one or more surfaces of the implant to encourage tissue ingrowth into the material and fixation of the dental implant. 
     In some exemplary embodiments provided according to the present disclosure, a dental implant includes: a base having exterior surfaces and a plug opening formed therein; a plug assembly inserted into the plug opening; and at least one region of porous ingrowth material associated with at least one of the exterior surfaces of the base. 
     In some exemplary embodiments provided according to the present disclosure, a method of treating a defect region in a mouth include placing an implantation bore in the defect region and implanting a dental implant into the implantation bore. The dental implant includes: a base having exterior surfaces and a plug opening formed therein; a plug assembly inserted into the plug opening; and at least one region of porous ingrowth material associated with at least one of the exterior surfaces of the base and in contact with tissue of the defect region. 
     One possible advantage that may be realized by exemplary embodiments provided according to the present disclosure is that the region of ingrowth material can allow the implant to quickly fixate and stabilize in tissue of the defect region. 
     Another possible advantage that may be realized by exemplary embodiments provided according to the present disclosure is that the implant can be easily adjusted to treat both contained and uncontained defect regions. 
     Yet another possible advantage that may be realized by exemplary embodiments provided according to the present disclosure is that the base can include a reservoir to elute one or more therapeutic agents into the defect region and further increase the recovery speed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an exploded perspective view of an exemplary embodiment of a dental implant provided according to the present disclosure; 
         FIG. 2  is an illustration of the dental implant of  FIG. 1  implanted in a defect region of a mouth of a patient; 
         FIG. 3  is an exploded perspective view of another exemplary embodiment of a dental implant provided according to the present disclosure; 
         FIG. 4  is a perspective view of the dental implant of  FIG. 3 ; and 
         FIG. 5  is an illustration of the dental implant of  FIGS. 3-4  implanted in a defect region of a mouth of a patient. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to  FIGS. 1-2 , an exemplary embodiment of a dental implant  100  for implantation within gingival tissue is illustrated. The dental implant  100  generally includes a base  110  with a plug opening  111  formed therein, a plug assembly  120  inserted into the plug opening  111 , and at least one region of ingrowth material  131 ,  132 ,  133 ,  134 , which are also referred to as “ingrowth regions,” associated with one or more respective surfaces  112 A,  112 B,  112 C of the base  110 . In some embodiments, as illustrated in  FIGS. 1-2 , the base  110  defines a generally cylindrical shape with a pair of increased diameter ends  113 A,  113 B and a body portion  114  between and connecting the ends  113 A,  113 B. In some embodiments, the base  110  comprises a generally non-porous material, which may have a porosity of between about 0% and about 10%. The base  110  may comprise one or more biocompatible materials suitable for short-term or long-term placement within an animal body, human or otherwise, which can include, but are not limited to: metals such as titanium, stainless steel, cobalt chrome, and/or tantalum; polymers such as ultra-high molecular weight polyethylene (UHMWPE), other forms of polyethylene, polyether ether ketone (PEEK), polylactic acid (PLA), and/or polyglycolic acid (PGA); and/or ceramics such as hydroxyapatite (HA), high-density alumina, so-called “Bioglass,” and graphite. It should be appreciated that all of the previously mentioned materials are exemplary only, and many other types of biomaterials can be incorporated in the base  110 . 
     In some embodiments, one or more fluid delivery grooves  115 A,  115 B are formed in the body portion  114  to deliver fluid from a reservoir  116  formed inside the base  110  to surrounding tissue, as will be described further herein. The surfaces  112 A and  112 C of the base  110  may also include one or more respective fluid delivery grooves  115 C. In some embodiments, two or more of the delivery grooves, such as grooves  115 A, extend circumferentially about a longitudinal axis LA defined through the base  110  and one or more of the delivery grooves, such as groove  115 B, extend parallel to the longitudinal axis LA to connect the circumferentially extending delivery grooves  115 A. The shape and size of the delivery grooves  115 A,  115 B may be adjusted to give differing fluid delivery behavior from the reservoir  116  of the implant  100  to surrounding tissue. The fluid delivery grooves  115 A,  115 B may fluidly communicate with the reservoir  116  formed in the base  110  via a reservoir opening  117  that is formed in the base  110  to the reservoir  116  and partially surrounded by the delivery groove  115 B. 
     A plug assembly  120  is inserted into the plug opening  111  of the base  110  to close the plug opening  111 . In some embodiments, the plug assembly  120  comprises a base engaging portion  121  with threads  122  that thread into corresponding threads of the base  110  to couple the base engaging portion  121  with the base  110 . The base engaging portion  121  may have a through-hole  123  extending therethrough that extends from one end  124 A of the base engaging portion  121  to an opposite end  124 B. In some embodiments, a stop  125  is formed in the base engaging portion  121  between the ends  124 A,  124 B to prevent the base engaging portion  121  from over-threading into the base  110 . The base engaging portion  121  may be unthreaded on one side of the stop  125 , such as adjacent to the end  124 A, and threaded on the other side of the stop  125 , such as adjacent to the end  124 B. 
     The plug assembly  120  may further include a plug portion  126  that is placed in the through-hole  123  of the base engaging portion  121 . The plug portion  126  may, for example, include a stem  127  with a diameter less than a diameter of the through-hole  123  and a head  128  having a diameter greater than the diameter of the through-hole  123  that is connected to the stem  127 . In some embodiments, the plug portion  126  may comprise a generally inelastic material, such as a thermoset polymer. Alternatively, the plug portion  126  may comprise an elastic material, such as rubber. It should be appreciated that the plug portion  126  should sufficiently fill the through-hole  123  of the base engaging portion  121  to plug the through-hole  123  so fluid from the reservoir  116  does not rapidly leak out of the through-hole  123  when subjected to increase fluid pressure. 
     In some embodiments, the through-hole  123  is formed in a mount  141  of the base engaging portion  121  that is shaped and sized to mount, for example, a replacement tooth thereon. In other words, the plug assembly  120  is configured to mount a replacement tooth thereon. The replacement tooth may fit directly on the mount  141  for fixation within the patient or, alternatively, an adapter may be fit on the mount  141 , with the replacement tooth then being mounted to the adapter. Many such mounts for replacement teeth are known, so further description of the mount  141  is omitted for brevity. 
     At least one region of ingrowth material, illustrated as four regions  131 ,  132 ,  133 ,  134 , is associated with one or more respective surfaces  112 A,  112 B,  112 C of the base  110 . As used herein, the ingrowth regions  131 ,  132 ,  133 ,  134  are “associated with” a respective surface of the base  110  in the sense that each ingrowth region  131 ,  132 ,  133 ,  134  is directly or indirectly fixated to its respective surface  112 A,  112 B,  112 C of the base  110 . To encourage tissue ingrowth, the ingrowth material of each region  131 ,  132 ,  133 ,  134  is porous and comprises a biocompatible material. Each region  131 ,  132 ,  133 ,  134  may comprise the same ingrowth material or, alternatively, one or more of the regions  131 ,  132 ,  133 ,  134  may comprise a different ingrowth material than one or more of the other regions  131 ,  132 ,  133 ,  134 . In some embodiments, the ingrowth material comprises titanium or polyether ether ketone (PEEK) having a porosity of between about 50% and 70%, a mean pore size of between about 500 μm and about 550 μm, a pore interconnectivity of between about 210 μm and about 250 μm, and a nominal thickness of between about 0.25 mm and 1.25 mm. One exemplary ingrowth material that may be used in one or more of the regions  131 ,  132 ,  133 ,  134  is commercially available under the tradename OSTEOSYNC® from SITES MEDICAL® of Columbia City, Ind. It should be appreciated that these characteristics of the ingrowth material(s) are exemplary only. In some embodiments, one of the regions, such as region  131 , is associated with the top surface  112 A of the base  110 ; one of the regions, such as region  132 , is associated with the circumferential surface  112 B of the base  110  between terminal end regions  113 A,  113 B of the base  110 , which are not covered by any ingrowth material; and two of the regions, such as regions  133  and  134 , are associated with the bottom surface  112 C of the base  110 . Each of the surfaces  112 A,  112 B,  112 C may have a through-hole formed through to the reservoir  116  to allow fluid delivery from the reservoir  116  to surrounding tissues through pores of the ingrowth regions  131 ,  132 ,  133 ,  134 . 
     In some embodiments, two of the ingrowth regions associated with the same surface, such as the ingrowth regions  133  and  134  associated with the bottom surface  112 C of the base  110 , differ from one another. For example, the ingrowth region  133 , which may be referred to as a “first region of ingrowth material” and sandwiched between the ingrowth region  134  and the bottom surface  112 C of the base  110 , may comprise a first ingrowth material that has a lower porosity compared to a second ingrowth material of the ingrowth region  134 , which may be referred to as a “second region of ingrowth material.” In other words, the first ingrowth material of the first region of ingrowth material  133  may have a first porosity and the second ingrowth material of the second region of ingrowth material  134  may have a second porosity that differs from the first porosity, e.g., by being greater than the first porosity. By providing the ingrowth region  133  with a lower porosity than the ingrowth region  134 , the fluid delivery rate to surrounding tissues from the reservoir  116  may be limited by the porosity of the ingrowth region  133  while the porosity of the ingrowth region  134  may be greater to encourage tissue ingrowth into the pores of the ingrowth region  134 . Such a configuration can allow long-term fluid delivery from the reservoir  116  to surrounding tissue, due to the relatively low porosity of the ingrowth region  133 , while providing larger pores in the ingrowth region  134  to encourage tissue ingrowth to stabilize the implant  100 . Alternatively, or in addition to, the two ingrowth regions  133 ,  134  may differ from one another by, for example, having different compositions and/or shapes. It should be appreciated that ingrowth regions associated with the same surface may differ from each other in other ways, and the foregoing examples represent only a few of the possible ways that the regions may differ from each other. 
     In some embodiments, a perforated sleeve  142  is placed between the circumferential surface  112 B of the base  110  and the ingrowth region  132  to provide a uniform surface for associating the ingrowth region  132  with the circumferential surface  112 B. As illustrated in FIG.  1 , the circumferential surface  112 B may be relatively non-uniform due to the formation of the fluid delivery grooves  115 A,  115 B, which makes securing the ingrowth region  132  to the surface  112 B difficult. The perforated sleeve  142 , therefore, fits on the circumferential surface  112 B, such as by press fitting, between the terminal end regions  113 A,  113 B of the base  110  to provide a uniformly sized surface for securing the ingrowth region  132 . Further, the size of apertures  143  formed in the perforated sleeve  142  may be adjusted to control fluid delivery through pores of the ingrowth region  132  by controlling the rate of fluid flow to the ingrowth region  132  from the reservoir  116  via the reservoir opening  117 . In this respect, the perforated sleeve  142  assists with associating the ingrowth region  132  with the circumferential surface  112 B of the base  110  as well as controlling fluid delivery from the reservoir  116  to surrounding tissues following implantation. 
     Referring specifically now to  FIG. 2 , the implant  100  is illustrated following implantation into gingival tissue T of a mouth of a patient, which may be a human or other animal. As illustrated in  FIG. 2 , a defect region  200  is present between two adjacent teeth  201 ,  202  in the patient. The defect region  200  previously held a tooth, which has fallen out or otherwise been removed due to, for example, disease or trauma. To replace the tooth, the defect region  200  is cleaned to remove remaining fragments of the removed tooth, other debris, and pathogens. In the case illustrated in  FIG. 2 , the defect region  200  is a contained defect that has sufficient amounts of local gingival and bone tissue to support and fixate the implant  100  without requiring, for example, one or more screws anchoring the implant  100 . 
     An implantation bore  203  is formed in the tissue of the defect region  200  and the implant  100  is placed within the implantation bore  203 . In some embodiments, the implantation bore  203  is formed by removing the tooth (or tooth fragments) that is present in the defect region  200  and is being replaced by the implant  100 . As illustrated, the mount  141  protrudes out of the implantation bore  203  following placement of the implant  100  to accept, for example, a replacement tooth after the implant  100  has sufficiently fixated within the tissue. Initially, however, the mount  141  may be left uncovered in the defect region  200 , exposing the mount  141  and the head  128  of the plug portion  126 . Before, during, or after implantation, the plug portion  126  may be removed from the through-hole  123  in the mount  141  and one or more therapeutic agents may be filled into the reservoir  116  within the base  110  via the through-hole  123 . The therapeutic agent(s) may be, but is not limited to, an antibiotic or other antimicrobial agent, an anti-inflammatory agent, an analgesic, a growth factor, a solution comprising regenerative cells such as stem cells, or any other substance that provides a therapeutic effect on the tissue surrounding the implant  100  following implantation. Alternatively, the therapeutic agent(s) may be filled into the reservoir  116  via, for example, the reservoir opening  117  prior to covering the reservoir opening  117  with the perforated sleeve  142  and the ingrowth region  132 . Thus, it should be appreciated that the reservoir  116  may be initially filled with one or more therapeutic agents in a variety of ways. 
     In some embodiments, the reservoir  116  is initially filled with a first therapeutic agent, which may be one or more antimicrobial agents to reduce the risk of infection, and then refilled with the first therapeutic agent, a second therapeutic agent that is different from the first therapeutic agent, or both while the implant  100  is implanted in the patient. For example, the reservoir  116  may be refilled partially with the first therapeutic agent (an antimicrobial) to continue delivering antimicrobial agent to surrounding tissue to reduce the risk of infection but also filled with a second therapeutic agent, such as a growth factor, to encourage tissue infiltration and ingrowth into the ingrowth regions  131 ,  132 ,  133 ,  134  to encourage a faster and more stable fixation of the implant  100  in the defect region  200 . To refill the reservoir  116 , the plug portion  126  may be pulled out of the through-hole  123  and a tip of a syringe containing the therapeutic agent(s) placed within the through-hole  123  to inject the therapeutic agent(s) from the syringe into the through-hole  123  and the fluidly coupled reservoir  116 . Alternatively, the syringe may also be used to remove fluid, which may be therapeutic agent or biological fluid, from the reservoir  116 . 
     After partially or fully filling the reservoir  116 , the plug portion  126  is replaced in the through-hole  123 . In some embodiments, the plug portion  126  is shaped and sized such that replacement of the plug portion  126  in the through-hole  123  pressurizes the fluid in the reservoir  116 , urging the fluid in the reservoir  116  out to the ingrowth regions  131 ,  132 ,  133 ,  134  via, for example, the reservoir opening  117  formed in the base  110 . In this respect, the plug portion  126  not only seals the through-hole  123 , but also provides an initial pressurization of the reservoir  116  to deliver a bolus of the therapeutic agent(s) to surrounding tissue while the implant  100  is implanted in the patient. After the initial bolus of therapeutic agent(s) is delivered, the remaining therapeutic agent(s) in the reservoir  116  may then travel out of the reservoir  116  into the surrounding tissue by compressive force exerted on the implant  100  “squeezing” out the therapeutic agent(s) as well as by natural diffusion of the therapeutic agent(s) into the tissue. It should be appreciated that the plug portion  126  may be removed from and replaced in the through-hole  123  multiple times throughout the implantation to refill the reservoir  116 . Due to the simplicity of removing and replacing the plug portion  126  to refill the reservoir  116 , the patient in which the implant  100  is implanted may refill the reservoir  116  at home or in other non-clinical settings. 
     While the implant  100  is implanted, native tissues adjacent to the defect region  200 , such as gingival tissue and bone tissue, may infiltrate and grow into the ingrowth regions  131 ,  132 ,  133 ,  134  of the implant  100 . As the native tissues grow into the ingrowth regions  131 ,  132 ,  133 ,  134 , the implant  100  becomes stably fixated within the tissue. After the implant  100  is stably fixated within the tissue, the replacement tooth may be mounted to the mount  141  to finish replacement of the removed tooth. In some embodiments, the replacement tooth may be mounted directly on the mount  141  with the plug portion  126  placed in the through-hole  123  of the base engaging portion  121 . In some embodiments, the plug portion  126  may be replaced with a different plug in the through-hole  123  that is shaped to both fill the through-hole  123  and engage, for example, a socket of the replacement tooth to mount the replacement tooth to the mount  141 . In other embodiments, the base engaging portion  121  may be replaced with a different base engaging portion having a mount for mounting the replacement tooth. It should thus be appreciated that many different ways of mounting a replacement tooth to the implant  100  may be used to fixate the replacement tooth to the implant  100 . 
     It has been discovered that certain ingrowth materials, such as the previously described OSTEOSYNC®, provide surprisingly good tissue ingrowth and fixation characteristics to the implant  100 . When OSTEOSYNC® is used to form the ingrowth regions  131 ,  132 ,  133 ,  134 , the push-out strength of the implant  100  may be roughly equivalent to the push-out strength of native bone after only 5 weeks of implantation. The results were surprising because of the high degree of improvement that such an implant provided compared to known dental implants. Without being bound to any particular theory as to why such results were observed, it is theorized that the ingrowth regions  131 ,  132 ,  133 ,  134 , when comprising OSTEOSYNC® or similar materials, provide an excellent substrate for cortical bone tissue ingrowth. Considering the high concentration of cortical bone tissue adjacent to the jawbone, it is theorized that the stable fixation of the implant  100  at five weeks is at least partly attributable to rapid ingrowth and proliferation of cortical bone tissue in the ingrowth regions  131 ,  132 ,  133 ,  134 . It is thus theorized that implants provided in accordance with the present disclosure are well-suited as dental implants because they simulate the natural fixation of teeth in the gingival tissue and the bone tissue present in the mouth of a patient, i.e., predominantly by ingrowth of and integration with adjacent cortical bone tissue. 
     It has also been found that providing one or more therapeutic agents in the reservoir  116  for therapeutic agent delivery during implantation encourages rapid, stable fixation of the implant  100 . As previously described, the reservoir  116  may be initially filled with one or more antimicrobial agents to reduce the risk of pathogens infecting the defect region  200  and interfering with tissue growth fixating the implant  100 . The reservoir  116  may be refilled one or more times with the antimicrobial agent(s), or other therapeutic agent(s), throughout the implantation, as previously described, to encourage tissue ingrowth into the ingrowth regions  131 ,  132 ,  133 ,  134  and stable fixation of the implant  100 . Therefore, the implants provided in accordance with the present disclosure may also encourage rapid, stable fixation in the surrounding native tissue by delivering one or more therapeutic agents into the surrounding tissue from the reservoir  116  to provide a favorable environment for tissue ingrowth into the ingrowth regions  131 ,  132 ,  133 ,  134 . 
     Referring now to  FIGS. 3-5 , another exemplary embodiment of a dental implant  300  for implantation within gingival tissue that has an uncontained defect is illustrated. Similarly to the previously described implant  100 , the implant  300  includes a base  310  with a plug opening  311  formed therein, a plug assembly  320  inserted into the plug opening  311 , and at least one region of ingrowth material  331 ,  332 ,  333 ,  334 ,  335  associated with one or more respective surfaces  312 A,  312 B,  312 C of the base  310 . As illustrated in  FIG. 3 , for example, the ingrowth regions  331  and  332  may be associated with the top surface  312 A of the base  310 ; the ingrowth region  333  may be associated with the peripheral surface  312 B of the base  310 ; and the ingrowth regions  334  and  335  may be associated with the bottom surface  312 C of the base  310 . Compared to the implant  100 , with a cylindrical base  110  having a generally circular cross-section, the implant  300  has a relatively larger base  310  with an oval cross-section to stabilize the implant  300  in an uncontained defect region  510 , which is illustrated in  FIG. 5  and described further herein. 
     Similarly to the base  110 , the base  310  can have fluid delivery grooves  315 A,  315 B,  315 C formed therein that communicate fluid from a reservoir  316  formed in the base  310  to, for example, the ingrowth regions  331 ,  332 ,  333 ,  334 ,  335  via openings, such as a reservoir opening  317 , formed in the base  310  to the reservoir  316 . The reservoir  316  may be refilled by removing a plug portion  326  from the plug assembly  320  and delivering fluid to the reservoir  316  through a through-hole  323  of the plug assembly  320  using, for example, a syringe or other fluid delivery device. The implant  300  may also include a perforated sleeve  342  between the ingrowth region  333  and the circumferential surface  312 B and have a mount  341  for mounting a replacement tooth, similarly to the implant  100 . 
     The implant  300  is configured to be implanted in an uncontained defect, i.e., a defect where adjacent tissue is diseased, destroyed, and/or otherwise unsuitable for fixating the implant  300  without additional fixation. To provide the additional fixation needed to stably fixate the implant  300 , one or more fixation openings  351 ,  352  may be formed in the base  310 , such as in the circumferential surface  312 B, to accept a respective fixator, such as one or more orthopaedic screws  501  (illustrated in  FIG. 5 ). Corresponding openings  353 ,  354  may also be formed in the perforated sleeve  342  and the ingrowth region  333  so the fixation openings  351 ,  352  are uncovered to accept the screw(s)  501 . The fixation opening(s)  351 ,  352  may be, for example, threaded to couple with the screw(s)  501  in order to fixate the implant  300  within the mouth of the patient. In this respect, implantation and use of the implant  300  is similar to that of the implant  100 , but also includes the additional step of fixating the fixator(s)  501  in a defect region, such as defect region  500  illustrated in  FIG. 5 , and coupling the fixator(s)  501  with the implant  300  by, for example, threading the fixator(s)  501  into the fixation opening(s)  351 ,  352 . In all other respects, implantation and use of the implant  300  may be similar to implantation and use of the implantation  100 , which is previously described. 
     While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.