1. Field of the Invention
The present invention relates to prosthetic devices such as implants and abutments, and in particular, to dental prosthetic devices with a surface that promotes soft tissue ingrowth.
2. Description of the Related Art
Dental prosthetic devices are commonly used as anchoring members for dental restorations to provide prosthetic teeth at one or more edentulous sites in a patient's dentition. Known dental implant systems include a dental implant made from a suitable biocompatible material, such as titanium. The dental implant is typically placed into a bore which is drilled into the patient's mandible or maxilla at the edentulous site. The implant provides an anchoring member for a dental abutment, which in turn provides an interface between the implant and a dental restoration or prosthesis. The restoration is typically a porcelain crown fashioned according to known methods.
Many current dental implant surgeries are performed in two stages. In the initial or first stage, an incision is made in the patient's gingiva at an edentulous side, and the bore is drilled into the patient's mandible or maxilla. The implant is then threaded or impacted into the bore using a suitable driver. Such an implant is typically called a subgingival or two-stage implant. The coronal end of the two-stage implant stops at the coronal surface of the alveolar and does not extend through the gingiva. Thereafter, a cap is fitted onto the implant to close the abutment coupling structure of the implant, and the gingiva is sutured over the implant. Over a period of several months, the patient's jaw bone grows around the implant to securely anchor the implant in the surrounding bone, a process known as osseointegration (note that herein jaw refers to either the mandible or maxillae).
In a second stage of the procedure following osseointegration, the dentist reopens the gingiva at the implant site and secures an abutment and optionally, a temporary prosthesis or temporary healing member, to the implant. The gingiva then grows around and against the abutment or healing member. Then, a suitable permanent prosthesis or crown is fashioned, such as from one or more impressions taken of the abutment and the surrounding gingival tissue and dentition. In the final stage, the temporary prosthesis or healing member is removed and replaced with the permanent prosthesis, which is attached to the abutment with cement or with a fastener, for example.
Alternatively, in a single-stage surgery, a transgingival implant extends through the gingival layer coronally of the alveolar. The transgingival implant may be part of a two-piece prosthetic device where the implant still requires an abutment to be placed upon it for loading. Other transgingival implants include a one-piece implant or prosthetic device. The one-piece implant has an integrally formed abutment that supports a prosthesis. In these cases, the gingiva grows around and against the transgingival implant during the healing period.
Before the gingiva has completely healed tightly around a prosthetic device extending through the gingival layer, the space between the gingiva and the prosthetic device may be relatively large. In this state, bone loss can occur when harmful, corrosive bacteria, similar to those encountered in periodontal diseases of natural teeth, grow between the prosthetic device and the gingiva and reach exposed bone adjacent the implant and underneath the gingival layer. One way to prevent such bone loss is to have the patient maintain thorough oral hygiene. To assist with this effort, a smooth surface is provided on the prosthetic device at and near the gingiva so that the implant or abutment is more easily cleaned of plaque, pathogenic organisms, and endotoxins than is a rough surface that has crevices that cannot be reached readily by dental cleaning devices such as brushes. Such a system, however, relies heavily on the oral hygienic habits of the patient who are often neglectful or simply may not be sufficiently skilled to adequately clean such a surface. Thus, improvements to more effectively limit bacteria from reaching bone adjacent a dental prosthetic device is desired.
Referring to
Although the abutment interface structure is shown here with an external hex shape to be received in an internally hex-shaped cavity on an implant, the arrangement may be reversed or may have other types of implant/abutment interfaces, such as threads or splines disclosed by U.S. Pat. No. 5,449,291, the disclosure of which is hereby incorporated by reference, or other geometric shapes such as octagons, lobes, and other shapes. A fastener bore 23 extends through the abutment 12 to receive a fastener to secure the abutment 12 to the implant 21.
In order to limit bacteria from reaching the jaw under the gingiva and adjacent an implant upon which the abutment 12 sits, the body 14 has a soft tissue engagement region 22 formed of porous metal material 24 for the ingrowth of soft tissue 30 (indicated in shadow line on
Thus, in the illustrated form, the soft tissue engagement region 22 forms an outer surface 26 on an emergence profile portion 28 formed on the abutment body 14 and that is embedded within soft tissue 30. The outer surface 26 is inclined to match a desired profile for the emergence profile portion 28 which generally matches the contour of natural teeth. The soft tissue engagement region 22 may also extend radially inward to provide further surface area and network structure for further engaging and holding the soft tissue to strengthen the connection between the soft tissue and the porous metal material 24. The soft tissue engagement region 22 also has an at least partially annular or ring shape. In one alternative form, the soft tissue engaging region 22 at least generally encircles the body 14 as in the illustrated example.
The body 14 has a main portion 32 that forms an annular recess or groove 34 that opens at least radially outward for receiving the porous material 24 to form soft tissue engagement region 22. In one case, only the outer surface 26 of the soft tissue engagement region 22 is exposed. The shape of the recess 34 is annular to coincide with the ring shape of the soft tissue engagement region 22 which, in one form, generally fills the recess.
It will be appreciated that many other shapes and configurations are possible for the soft tissue engagement region such as extending on only a portion or portions of the circumference of the body 14, whether a single continuous piece or separate pieces spaced around the circumference. Likewise, the soft tissue engagement region may only be a thin layer or surface on the body 14 rather than extending significantly radially inward, or may extend radially inward only at certain points or portions of the body 14 rather than all the way around the body 14.
While the illustrated abutment 10 shows the porous metal material 24 only located where soft tissue faces the abutment, it will be understood that the porous metal material 24 may extend conronally or apically beyond this region as may be desired and as explained further below.
In one form, the porous metal material 24 is a porous tantalum portion 40 which is a highly porous biomaterial useful as a bone substitute and/or cell and tissue receptive material. An example of such a material is produced using Trabecular Metal™ technology generally available from Zimmer, Inc., of Warsaw, Ind. Trabecular Metal™ is a trademark of Zimmer Technology, Inc. Such a material may be formed from a reticulated vitreous carbon foam substrate which is infiltrated and coated with a biocompatible metal, such as tantalum, etc., by a chemical vapor deposition (“CVD”) process in the manner disclosed in detail in U.S. Pat. No. 5,282,861, the disclosure of which is fully incorporated herein by reference. Other metals such as niobium, or alloys of tantalum and niobium with one another or with other metals may also be used.
Generally, as shown in
The porous tantalum structure 40 may be made in a variety of densities in order to selectively tailor the structure for particular applications. In particular, as discussed in the above-incorporated U.S. Pat. No. 5,282,861, the porous tantalum may be fabricated to many different desired porosity and pore sizes, and can thus be matched with the surrounding soft tissue (and/or natural bone if desired) in order to provide an improved matrix for soft tissue (and/or bone) in-growth and mineralization. This includes a gradation of pore size on a single implant such that pores are larger on an apical end to match cancellous bone, and smaller on a coronal end to match cortical bone, or even to receive soft tissue ingrowth. Also, the porous tantalum could be made denser with fewer pores in areas of high mechanical stress. This can be accomplished by filling all or some of the pores with a solid material which is described in further detail below.
The main portion 32 may be made of metal, such as titanium, and the porous material 24 may be sintered or otherwise diffusion bonded to the main portion 32. When the main portion 32 is made of a ceramic, polymer, or other composites, the porous material 24 may be adhered to such materials. The porous material 24 may be alternatively or additionally press-fit or friction-fit into the groove 34 on the main portion 32.
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It will also be understood that any of the soft tissue engagement regions described above may be placed on a one-piece prosthetic device with a body that has an implant portion configured for engaging jaw bone tissue and integrally formed with an abutment. In one form, the porous metal may be located only at the soft tissue engaging region on the dental prosthetic device. Alternatively, the porous metal may be placed on other parts of the prosthetic device as described for the other embodiments to additionally engage bone for example
Referring to
For the one-piece dental device 120, the core 122 also is made of a porous metal such as tantalum as described above and may be received by an interior or bore 137 of the sleeve 138. The core 122 can be inserted into the sleeve 138 by various methods such as press-fit or mechanical threading as described above. Alternatively, the sleeve 138 may be integrally formed with the core 122. While the porous metal portion 124 generally remains on the implant portion 130 (i.e. it does not extend substantially onto the abutment portion 126 in this example), the porous metal core 122, in one form, widens and forms the bulk of the abutment portion 126 and forms a strong, reinforcing post that extends from within the implant or anchor portion 130 to within the abutment portion 126. Thus, in this case, the porous metal, and therefore, the porous metal portion 134, may be described as generally extending throughout the prosthetic device 120.
For the dental device 120, the core 122 is impregnated with a filler to provide additional mechanical strength and stability to the porous structure. The filler may be a composite material, which may be the same as the esthetic material 142 as shown in the illustrated example here, and may fill in the vacant open spaces in the porous tantalum. Alternatively, or additionally, the filler material may be a non-resorbable polymer. Examples of non-resorbable polymers for infiltration of the porous structure may include a polyaryl ether ketone (PAEK) such as polyether ketone ketone (PEKK), polyether ether ketone (PEEK), polyether ketone ether ketone ketone (PEKEKK), polymethylacrylate (PMMA), polyetherimide, polysulfone, and polyphenolsulfone.
In the illustrated form, the composite or polymer material fills the pores of the entire length of the core 122 from the proximal end portion 128 to the distal end portion 132 although the filler may be present at less than this. The porous metal portion 124 forming the sleeve 138 and that forms the exterior of the implant portion 130 for engaging bone is substantially free of the esthetic material to receive the ingrowth of bone.
The esthetic material or esthetic portion 142 of the one-piece dental device 120, as mentioned above for the dental device 20, may be disposed at at least the outer portion 134 at the abutment portion 126 for esthetics and to at least partially cover the porous tantalum portion of the core 122 at the proximal portion 128 to limit gingival tissue growth there. Thus, at the proximal end portion 128 of the core 122, the outer portion 134 forms a smooth esthetic skin layer that is substantially free of porous tantalum, and is located around substantially the entire abutment portion 126. The outer portion 134 may have a skin layer that is approximately 0.05 to about 3.0 mm thick. With this configuration, the porous sleeve 138 substantially covers the implant portion 130 of the outer layer of the implant 120 to promote bone growth while the exposed abutment portion 126 with a solid, smooth esthetic outer surface limits the in-growth of soft tissue and bacterial growth against the abutment portion 126.
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In order to promote soft tissue growth to form a strong bacterial seal, however, one or more gaps 144 may be provided on the upper layer 140 to encourage soft tissue ingrowth to form a seal around the perimeter of the implant 120 at the location of the gap 144. This seal coupled with the non-porous outer surface formed by the esthetic portion 142 on the abutment portion 126 forms a barrier that limits bacteria, epithelium or other contaminants from passing through the porous metal of sleeve 138 and into a bone integration area along the implant portion 130. It is clearly inherent that gap 144 may be disposed anywhere on abutment portion 126 to expose empty pores of the porous metal of the core 122 (or porous metal may form a core of the upper layer 140) for soft tissue ingrowth. In this case, the soft tissue grows into the core's porous metal for a strong bond as similarly described for the other embodiments herein. While the gap 144 is shown as a continuous gap around the upper layer 140 it will be appreciated that many other forms are possible, such as non-continuous gaps, spaced holes, or other uniform or more randomly placed openings, to name a few examples.
Referring now to
Examples of resorbable polymers may include polylactic co-glycolic acid (PLGA), polylactic acid (PLA), polyglycolic acid (PGA), polyhydroxybutyrate (PHB), and polyhydroxyvalerate (PHV), and copolymers thereof, polycaprolactone, polyanhydrides, and polyorthoesters. It will be understood that such resorbable filler material may be used on any of the abutment or implant forms described herein.
The porous portion 222 may be made of tantalum or other materials as described above and, in broad terms, an outer portion 240 of the dental device 220 has a color generally replicating the color of natural teeth and comprises an esthetic portion or material 224. More specifically, the dental device 220 has a coronal end portion 234 that forms an abutment portion 232, and the esthetic portion 224 is placed on the abutment portion 232. The porous portion 222 forms a reinforcing core 236 of the abutment portion 232. While the core 236 is shown to extend approximately half the height of the abutment portion 232, it will be understood that other variations are possible including the core 236 extending at or near the terminal coronal end 234 of the abutment portion 232, or being much shorter such that the core 236 extends a relatively small distance into the abutment portion 232. In the illustrated form, the core 236 does not extend near the terminal coronal end 234 so that the esthetic portion 224 disposed coronally of the core 236 is separate from the porous portion 222 and is substantially free of porous metal so that the end 234 is easily shaped similar to coronal upper layer 140 of dental device 120 (
It will be appreciated that the outer portion 240 may be located on any outer part of the abutment portion 232 and may be substantially free of the porous portion 222 as with the other embodiments herein. The outer portion 240 may contain a smooth exterior layer that has a minimal width of about 1 mm on the sides of the core 236 and/or may have a substantial thickness of about 1 to about 5 mm above the coronal end 226 of the core 236.
While the resorbable material 242 is only placed to interface with bone apically of the crest of the alveolar in the illustrated embodiment, it will be understood that the resorbable material may be placed in a transgingival section of the prosthetic device 220 to interface with the soft tissue, or may be placed behind the esthetic material 224 to strengthen the porous structure 222.
When the resorbable material 242 is used for strengthening the porous structure 222 as in the illustrated embodiment, the resorbable material 242 should be placed throughout all of the pores (or at least within the pores that the bone will be able to grow into). It will be understood, however, the resorbable material 242 could be primarily placed to control soft tissue growth. In this case, the resorbable material may optionally be placed only where soft tissue is likely to grow, such as within a range (indicated by brackets 244) of about 3 mm apically from the coronal crest of the alveolar. Alternatively, the resorbable material could be placed to mainly interface with cortical bone rather than cancellous bone.
While the illustrated forms are shown to be dental implants, it will be understood that such structures may be applied to other areas of an animal or human body. Thus, implants with porous material such as a porous metal, or more specifically porous tantalum, for promoting or controlling the ingrowth of soft tissue and/or bone tissue whether or not used with a filler material such as a resorbable material to add strength to the implant may also be used in soft tissue (whether overlaying bone or as part of organs, etc.) and/or bones other than at a mandible or maxillae.
While this invention may have been described as having a preferred design, 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.
This application is a continuation-in-part of pending U.S. patent application Ser. No. 11/847,476, filed Aug. 30, 2007, which is incorporated herein by reference in its entirety for all purposes.
Number | Date | Country | |
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Parent | 11847476 | Aug 2007 | US |
Child | 12167004 | US |