CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 62/267,023, filed December 14, 2015, which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[0002] This invention relates generally to the field of oral surgery and periodontics and, in particular, to a gingival socket seal membrane device and methods of using the same to maintain hard and soft tissue architecture of a tooth-extraction site.

BACKGROUND OF THE INVENTION

[0003] In an era of dentistry driven by high aesthetic demands and standards, post- extraction tissue loss can pose a considerable aesthetic, surgical, and/or restorative challenge. In vivo studies report up to about 3-6 mm of bucco-lingual volumetric remodeling within the first six months following extraction of non-molar teeth. This dimensional change is attributed to facial tissue collapse in the edentulous space, which can significantly alter the midfacial gingival architecture and create an unaesthetic "shadowing" effect around the final restoration. It is critical to consider proper tissue management during the treatment planning phase to achieve consistent treatment outcomes.

[0004] Several procedures have been proposed to assist in addressing the disadvantages associated with post-extraction tissue loss. Surgical interventions include extraction socket preservation techniques and immediate implant placement with alveolar bone grafting, which are two clinically-proven methods used to minimize significant post-extraction hard and soft tissue dimensional changes. However, immediate implant placement with bone grafting may not be a viable treatment option in certain clinical situations such as inadequate buccal plate volume post-extraction and patients with medical limitations, limited time, and/or limited finances.

[0005] Limiting factors in conventional extraction socket preservation techniques include the reabsorbable nature of "protective membranes" used to contain hard tissue-grafting material(s). Namely, the membranes tend to dissolve within weeks due to the enzymatic action of saliva, which degrades collagen substrates. Moreover, existing membranes typically do not properly conform to the gingival or "gum side" of an extraction socket since they are not anatomic in shape or tooth-specific. Rather, existing devices generally have geometric shapes such as cylinders, rectangular or triangular sheets or "cones," and "tape." Also, peri-implant soft tissue tends to collapse very shortly after tooth extraction, and the goal of treatment is to revert the soft tissue to its pre-extraction state and gingival morphology.

[0006] It is important to maintain the shape of the edentulous ridge for aesthetic and restorative reasons since periodontal tissues play an essential role in maintaining and preserving the gingival architecture and dental aesthetics of a patient's smile. Maintenance and preservation of existing hard and soft tissues in their anatomic form following tooth removal is generally referred to as guided soft tissue preservation (GSTP) and is a main goal of treatment in sites not immediately receiving a dental implant or a transitional or definitive restoration. The treatment benefit of GSTP in the posterior region of the mouth is functional, where minimizing bucco-lingual collapse minimizes the potential for food impaction.

[0007] The present invention is directed to an improved gingival socket seal membrane device and methods of using the same to maintain hard and soft tissue architecture of a tooth- extraction site.

SUMMARY OF THE INVENTION

[0008] In one embodiment described herein, a soft and hard tissue maintenance and preservation membrane device for a tooth-extraction site is disclosed. The membrane device includes a generally curved apical end. The apical end is configured to rest in a tooth- extraction socket and substantially conform to soft tissue and hard tissue of the tooth- extraction site immediately after a tooth has been extracted. The membrane device further includes an opposing, generally concave coronal end. The coronal end has a perimeter that is configured to substantially correspond and form a seal with gingival tissue surrounding the tooth-extraction site. The membrane device is anatomically shaped and is made from a resorbable material.

[0009] In one process described herein, a dental restoration method is disclosed. The method includes extracting a tooth from a tooth-extraction site. The tooth-extraction site has gingival tissue surrounding the tooth. The extracting results in an extraction socket having soft and hard tissue positioned therein. The method further includes applying a hard tissue- grafting material into the extraction socket. The method further includes selecting a resorbable membrane device having an apical end substantially conforming to a shape of the extraction socket immediately following the extraction and a coronal end having a perimeter substantially conforming to the gingival tissue surrounding the tooth-extraction site immediately following the extraction. The method further includes applying the selected resorbable membrane device to the extraction socket. The resorbable membrane device generally inhibits or prevents the hard tissue-grafting material from exiting the extraction socket. The resorbable membrane device further assists in substantially maintaining the shape of the soft and hard tissue within the extraction socket and the gingival tissue surrounding the tooth-extraction site during healing.

[0010] In another embodiment, a kit of components for maintenance and preservation of a tooth-extraction site is disclosed. The kit includes a plurality of resorbable membrane devices. Each of the plurality of devices has a generally curved apical end and an opposing, generally concave coronal end. The apical end is configured to rest in a tooth-extraction socket and substantially conform to soft tissue and hard tissue of the tooth-extraction site immediately after a tooth has been extracted. The coronal end has a perimeter that is configured to substantially correspond and form a seal with gingival tissue surrounding the tooth-extraction site. The apical and coronal ends of each of the plurality of devices have (1) different shapes, each of the different shapes corresponding with a different tooth-extraction site location, or (2) substantially the same shape and different sizes.

[0011] In another embodiment, a membrane device for a tooth-extraction site is disclosed. The membrane device includes a generally curved apical end having an exterior surface for inhibiting bone-grafting material from exiting the tooth-extraction site. The membrane device further includes a side wall extending away from the apical end. The side wall has an anatomical shape so as to form gingival tissue surrounding the tooth-extraction site into a shape generally corresponding to the anatomical shape. The membrane device is made from a resorbable material, a non-resorbable material, or a combination of resorbable and non-resorbable materials.

[0012] In another embodiment, a dental component system for developing a prosthetic tooth at a tooth-extraction site is disclosed. The system includes a membrane device having an apical end that inhibits bone-grafting material from exiting the tooth-extraction site. The membrane device has a side wall with a shape to form gingival tissue surrounding the tooth- extraction site into an anatomical shape. The system further includes a pontic that includes a first part that fits into the tooth-extraction site and a second part that provides a visible part of the prosthetic tooth. The first part has a shape that generally corresponds with the shape of the side wall of the membrane device. The pontic is used at the tooth-extraction site after tissue has substantially healed by use of the membrane.

[0013] In another embodiment, a dental component system for developing a prosthetic tooth at a tooth-extraction site is disclosed. The system includes a resorbable membrane device having an apical end that inhibits bone-grafting material from exiting the tooth- extraction site. The membrane device has a side wall with a shape to form gingival tissue surrounding the tooth-extraction site into an anatomical shape. The system further includes a pontic that includes a first part that fits into the tooth-extraction site and a second part that provides a visible part of the prosthetic tooth. The first part has a shape that generally corresponds with the shape of the side wall of the membrane device prior to the membrane device being inserted into the tooth-extraction site. The pontic is used at the tooth-extraction site after tissue has healed by use of the membrane device.

[0014] In another embodiment, a dental component system for developing a prosthetic tooth at a tooth-extraction site is disclosed. The system includes a membrane device having an apical end that inhibits hard tissue-grafting material from exiting the tooth-extraction site. The membrane device has a side wall with a shape to form gingival tissue surrounding the tooth-extraction site into an anatomical shape. The system further includes a pontic that includes a first part that fits into the tooth-extraction site and a second part that provides a visible part of the prosthetic tooth. The first part has a shape that generally corresponds with the shape of the side wall of the membrane device but with smaller diametric dimensions to account for dimensional changes in the gingival tissue during gingival healing that may occur during use of the membrane device.

[0015] In another embodiment, a dental restoration method is disclosed. The method includes extracting a tooth from a tooth-extraction site. The extracting results in an extraction socket having soft and hard tissue positioned therein. The method further includes applying a grafting material into the extraction socket adjacent to the hard tissue. The method further includes selecting a membrane device having an apical end substantially conforming to a shape of the extraction socket and a coronal end having a perimeter for forming the gingival tissue into an anatomic shape. The method further includes applying the selected membrane device to the extraction socket so as to inhibit the grafting material from exiting the extraction socket and to form the gingival tissue. The method further includes, after healing of the soft and hard tissue with the membrane device, applying a pontic to the tooth-extraction site. The pontic has a shape that generally corresponds with the shape of the membrane device.

[0016] The above summary of the present invention is not intended to represent each embodiment or every aspect of the present invention. This is the purpose of the figures and the detailed description that follow. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.

[0018] FIG. 1 is a gingival or apical view of a gingival socket seal membrane device according to one embodiment described herein.

[0019] FIG. 2 is a distal view of the membrane device of FIG. 1.

[0020] FIG. 3 is a facial or labial view of the membrane device of FIGs. 1-2.

[0021] FIG. 4 is an occlusal view of the membrane of FIGs. 1-3.

[0022] FIG. 5 is a sequence of related images from tooth extraction to placement of a membrane device.

[0023] FIG. 6 illustrates various views of a kit of gingival socket membrane devices configured to be used, respectively, in different tooth extraction locations in a patient's mouth.

[0024] FIG. 7 illustrates digital images (e.g., from stereolithography (STL) files) corresponding with the devices of FIG. 6.

[0025] FIG. 8 illustrates various views of a membrane device described herein configured to be used following the extraction of a central incisor tooth (#8).

[0026] FIG. 9 illustrates various views of a membrane device described herein configured to be used following the extraction of a molar tooth (#30).

[0027] FIG. 10 illustrates an example of a dental restoration method in accordance with the embodiments described herein.

[0028] FIG. 11 illustrates a pontic device that may be used with the membrane devices described relative to FIGs. 1-10, according to one embodiment.

[0029] FIG. 12 illustrates a 3-unit fixed dental prosthesis in which the central pontic has an apical end with a size and shape that is dictated by the membrane devices described relative to FIGs. 1-10.

[0030] While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION [0031] The embodiments discussed herein are directed to hard and soft tissue maintenance and preservation arrangements for tooth-extraction sites that comprise a gingival socket seal membrane device. The membrane device includes a generally semilunar, curved apical end that substantially corresponds with the shape of soft and/or hard tissue of a tooth- extraction site immediately following tooth removal. The membrane device further includes a second generally opposite, generally concave, coronal end with a perimeter that generally corresponds in shape with the gingival tissue around the tooth-extraction site immediately following tooth removal. The outer perimeter portion of the membrane device contacts the supragingival soft tissue generally without spaces or gaps between the device and the supragingival soft tissue.

[0032] The membrane devices described herein are tooth-specific for capturing the supragingival tissues of an extraction socket and anatomically mimic the cervical portion of the tooth root cervix to maintain the shape and volume of the dentogingival complex following tooth removal. The membrane devices provide a quick, anatomically correct "scaffold" to help support the gingiva after tooth extraction by conforming to and generally maintaining the pre-extraction state of the tooth root cervix.

[0033] FIG. 1 is a gingival or apical view of a gingival socket seal membrane device 10 according to one embodiment for use in replacement of a tooth. The membrane device 10 further includes a side wall extending away from the apical end. The side wall has an anatomical shape so as to form gingival tissue surrounding the tooth-extraction site into a shape generally corresponding to the anatomical shape. As can be seen, the membrane device 10 has a generally scalloped shape in that some portions of the side walls are higher and some portions are lower.

[0034] As illustrated in FIG. 1, the membrane device 10 has a perimeter shape and an apical shape configured to anatomically mimic the soft tissue of the extraction socket that remains immediately after a tooth has been extracted and before the soft tissue of the extraction socket begins to shrink, collapse, and/or shift from its pre-extraction size, shape, and/or position. The outer perimeters of the membrane device 10 include a mesial-apical portion 11, a distal-apical portion 12, a lingual-apical portion 13, and a facial-apical portion 14 configured to contact an outer surface of the gingival tissue around the extraction socket and, optimally, to create a biologic seal of the tissue zone, as shown, for example, in FIG. 5.

[0035] FIG. 2 illustrates a distal view of the membrane device 10 of FIG. 1 showing a buccal portion 15 and a lingual portion 16 of the device 10. The membrane device 10 includes a distal peak 17 that supports the distal papilla and a mesial peak 18 that supports the mesial papilla. The membrane device 10 further includes a rounded or dome-shaped apical portion 19 that rests in the extraction socket and generally adapts to the immediate socket and the gingival soft tissue. The apical portion 19 assists in preventing shrinkage of the extraction socket as well as inhibiting or preventing the outflow of hard tissue-grafting material that may be placed into the extraction socket. The membrane device 10 further includes a distal interface or transition zone 20, a buccal-distal interface 21, and a lingual-distal interface 22 that are configured to contact the junction of the soft tissues and bony walls (bone zone) of the extraction socket. The transition zone 20 is designed to provide an anatomical emergence-profile shape for the soft tissue adjacent to the extraction socket so as to form gingival tissue surrounding a tooth-extraction site into a shape generally corresponding with the pre-extraction anatomical shape.

[0036] FIG. 3 shows a facial view of the membrane device 10 of FIGs. 1 and 2. Lingual interproximal portion 31 generally supports the lingual interproximal aspect of the papilla. Transition interfaces 33, 34 are positioned between the extraction socket bony walls and gingival soft tissues (tissue zone). A facial aspect 36 of the membrane device 10 may optionally connect the membrane device 10 to the coronal portion of a false tooth pontic (see, e.g., FIGs. 11, 12).

[0037] FIG. 4 illustrates an occlusal view of the membrane device 10 of FIGs. 1-3. A semi-open portion 41 of the membrane device 10 may attach to a coronal tooth portion of a pontic. The mesial-occlusal portion 42, the Ungual-occlusal portion 43, the distal-occlusal portion 44, and the bucco-occlusal portion 45 are also shown.

[0038] The membrane devices 10 described herein may provide or assist in providing a physical barrier for hard tissue- (e.g., bone) grafting material that may be placed within the extraction socket during its full maturation phase (which may require up to six months of healing time). The membrane devices 10 may also provide or assist in providing a biological seal for both the soft tissue and the extraction socket, thereby assisting in precluding bacteria and environmental contaminants from soft tissue from entering into the extraction socket during guided soft tissue preservation.

[0039] The gingival socket membrane devices described herein may be constructed of various suitable materials having a known reabsorption rate. For example, the membrane device 10 may be formed from one or more reabsorbing materials having a known resorbtion rate such as, for example, dense collagen (xenograft), polymer of lactic acid or glycolic acid, alloplastic materials, combinations thereof, or the like. The resorbable material(s) may be expected to resorb in, for example, about 3 months to about 6 months. Alternatively, the resorbable material(s) may be selected so as to resorb in less time, such as about 3 weeks to about 8 weeks. In another embodiment, the membrane device 10 may be formed from one or more generally non-reabsorbable materials (e.g., expandable Polytetrafluoroethylene (ePTFE), Polymethymethacrylate (PMMA), hydroxyapatite particles (HA), or the like). Use of collagen and/or PMMA may be desirable, since these materials are generally less prone to plaque accumulation. Collagen is also susceptible to dissolution by salivary enzymes that assist in breaking down the collagen matrix, which may also be desirable.

[0040] The membrane devices 10 described herein may be comprised of multiple materials. For example, a first non-resorbable material may be formed into a matrix-type structure and a second resorbable material (e.g., collagen) may then be used to fill in the voids within the matrix. Alternatively, the apical portion 19 that is adjacent to the bone and bone-grafting material may form a base of the membrane device 10 and comprise a first material, while a second material may be used for the portions of the membrane device 10 that are designed to engage the gingival tissue. In such an arrangement, the first material may be resorbable (or slowly resorbable) while the second material may be non-resorbable (or vice versa).

[0041] In one embodiment, a "hybrid" stratified membrane includes variable reabsorbing materials. For example, a top, coronal portion may be formed of slowly resorbing dense collagen, a middle portion may be formed of a moderately resorbing composite material, and a bottom, apical portion may be formed of a moderately resorbing putty matrix.

[0042] Resorbable membrane devices described herein generally have a thickness from about 2 mm to about 9 mm from the midfacial aspect and from about 5 mm to about 14 mm inter proximally. Non-resorbable membrane devices described herein generally have a thickness from about 2 mm to about 4 mm from the midfacial aspect and from about 5 mm to 9 mm inter proximally. The surfaces of the membrane devices 10 may have different types of roughnesses and micro-porosities. For example, a minimum roughness of about 6 microns to about 20 microns may be used on the gingiva-facing surfaces of the membrane device to promote attachment of soft tissue to the membrane device 10, especially when the membrane device 10 is made of resorbable material.

[0043] The membrane devices 10 described herein may be supplied in a kit that includes one or more membrane devices per tooth-extraction site location in a patient's mouth. As shown, for example, in FIG. 6 (described in more detail below), each tooth to be removed (and corresponding tooth-extraction site location) requires a membrane device having a different shape and/or dimension to correspond therewith. As such, a kit may be provided that includes a plurality of membrane devices, each of which corresponds with a respective tooth-extraction site location. The kit may be presented and/or made such that the membrane devices are (or appear to be) connected to one another.

[0044] A plurality (e.g., a kit) of membrane devices may also be provided for a single tooth-extraction site location, where each of the plurality of devices is more patient-specific. For example, a plurality of membrane devices of varied sizes may be supplied having the same general shape, thereby being configured for use in the same tooth-extraction site location. A dental clinician may select an appropriate size more customized to a particular patient, since tooth and tooth-extraction site sizes will vary among individuals.

[0045] Accordingly, a membrane device 100 may be selected such that the selected membrane device 100 corresponds with (1) the tooth to be removed / tooth-extraction site location and/or (2) the size/dimensions best suited for the specific patient in which the membrane device is to be placed. Once a proper membrane device 10 is selected from the variety of types and/or sizes, it may be placed within the tissue zone of the extraction socket.

[0046] FIG. 6 illustrates one example of a kit 95 including a plurality of membrane devices 100. The first and second rows 110, 120 of FIG. 6 illustrate facial and facial-occlusal views, respectively, of the membrane devices 100. The third row 130 illustrates occlusal views of the membrane devices 100. From left to right, the illustrated membrane devices 100 are configured to be used in a tooth-extraction site corresponding with location of #4 or #5 (bicuspids), #6 (canine), #7 (lateral incisor), #8 (central incisor), #9 (central incisor), #10 (lateral incisor), #11 (canine), and #12 or #13 (bicuspids). Put another way, each column of FIG. 6 shows a tooth-specific membrane device used to replace one of teeth #4-13. Each of the membrane devices 10 is preferably modifiable, predominantly in length, by the clinician to match the tooth-extraction site of the prevailing conditions in the patient's mouth. In other words, the kit of membranes provides the clinician with some flexibility in selecting the best membrane device 10 for a certain tooth, but the clinician may still perform some modifications to make the membrane device 10 even more patient-specific.

[0047] FIG. 7 illustrates images from digital files corresponding to the membrane devices of FIG. 6 for ease of manufacturing. In one embodiment, the files are in a stereolithography (STL) format so that they may be produced from, e.g., a rapid-prototyping manufacturing technique. Such techniques may be used to manufacture the standardized shapes of the membrane devices described herein by tooth number.

[0048] In one embodiment, a patient's natural tooth that has been extracted may undergo a scanning process to determine its overall size and shape. The scanning process results in a data file that permits a 3D image of the patient's natural tooth to be displayed on a display device. An operator may then select a portion of the patient's natural tooth within the trans- gingival region to develop a shape for a patient-specific membrane device 10. The membrane device 10 is then developed with a shape that substantially corresponds with the shape of the patient's natural tooth that has been extracted.

[0049] FIG. 8 illustrates various views of a membrane device 150 described herein configured to be used following the extraction of a central incisor tooth (#8). From left to right, FIG. 8 illustrates the following views: occlusal (O), apical (A) and distal (D), coronal (C), and apical (A) and mesial (M). Similarly, FIG. 9 illustrates various views of a membrane device 160 described herein configured to be used following the extraction of a molar tooth (#30). From left to right, FIG. 9 illustrates the following views: buccal (B), coronal (C), mesial (M), and apical (A).

[0050] A dental restoration method according to one embodiment is illustrated in FIG. 10. At step 200, a dental restoration method includes extracting a tooth from a tooth- extraction site, where the tooth-extraction site has gingival tissue surrounding the tooth. The extraction results in an extraction socket having soft and hard tissue positioned therein. At step 210, a hard tissue-grafting material is applied into the extraction socket. A resorbable membrane device may then be selected at step 220. The method further includes applying the selected resorbable membrane device to the extraction socket at step 230. The membrane device may be stabilized in a proper position with sutures.

[0051] The membrane devices 10 described herein are generally effective in providing structural support to the hard and soft tissue and gingival surface associated with a tooth- extraction site, which assists in preserving the aesthetic and anatomic architecture of the tooth-extraction site after tooth removal. The membrane devices 10 assist with endentulous ridge management (both immediate and delayed) independent of clinical crown position and site development and tissue conditioning prior to delayed implant placement. Additionally, the membrane devices 10 assist in inhibiting the outflow of bone-grafting material that may be inserted adjacent to the hard tissue of the extraction socket resulting from the tooth extraction. As such, the membrane device 10 of the present invention serves two primary functions: (i) maintaining the bone-grafting material within the tooth-extraction site; and (ii) maintaining a more natural gingival profile. As described below, when a pontic device is used after the membrane, the gingival tissue will have a more natural emergence profile, thereby providing enhanced aesthetics for the pontic. [0052] According to one embodiment, the shape and design of the gingival socket membrane device 10 may be scanned into stereolithography (STL) files with the associated volumetric dimensions for the digital (e.g., CAD/CAM) fabrication thereof. STL files are 3- dimensional CAD/CAM (computer-aided design/computer-aided manufacturing) files stored in a computer database. The STL files may be used to create physical pieces of the device. The STL files are generally tooth-specific, accounting for all of the teeth in the dentition of both jaws with the possible exception of the third molars (28 in total). It is contemplated that other technologies may also "print" the devices using, e.g., 3D printing machines, which may add sequential layers of material by spraying onto a substrate and then polymerizing with a light-activated source.

[0053] As discussed below relative to FIG. 11, once the shape and design of the membrane are known, a pontic can be developed that has an apical portion substantially matching the size and shape of the membrane device 10. Once the patient's gingival tissue and bone tissue heals by use of the membrane device 10 after an extraction, the pontic can be placed at the tooth-extraction site and supported by the adjacent teeth or the adjacent dental implants (or a combination thereof). Alternatively, the pontic may have a shape that matches the interior geometry of the membrane device, such that it is slightly smaller in size and shape than the exterior surfaces of the membrane device 10 when initially placed.

[0054] The devices described herein may also be used with a pontic 200 shown in FIG. 11. The membrane device and the pontic 200 may be used as part of a dental component system for developing a prosthetic tooth at a tooth-extraction site. The pontic 200 may be a two-part device having a lower portion 202 that fits into the tooth-extraction site and an upper tooth-shaped portion 204 that provides a visible part of the prosthetic tooth. The lower portion 202 has a shape that generally corresponds with the shape of the side wall of the membrane device but with smaller diametric dimensions to account for dimensional changes in the gingival tissue during gingival healing that may occur during use of the membrane device. The upper portion 204 is typically attached at both side edges to adjacent prosthetic teeth (on the right and left) that are supported by natural tooth roots, by dental implants, or by a combination thereof.

[0055] An example of a 3-unit fixed dental prosthesis 240 is shown in FIG. 12. In one embodiment, a gingival ovate pontic may be applied after the tooth-extraction site/socket has healed and/or when a transitional or conventional bridge is to be applied. A pontic may be used in situations where an immediate implant or transitional restoration is not placed at the time of tooth removal. The tooth-extraction site may be maintained using the membrane device described herein, and a pontic (e.g., a gingival ovate pontic) may later be attached to a fixed prosthesis after tissue has substantially healed by use of the membrane device.

[0056] It is contemplated that the gingival socket membrane device 10 may include one or more apertures through which a suture may be threaded. As such, the gingival socket membrane device 10 may be easily sutured to the tooth-extraction site immediately after a tooth has been extracted.

[0057] The membrane devices described herein may be used in lieu of conventional guided bone regeneration (GBR) for immediate post-extraction socket ridge preservation in Type 1 (intact) extraction sockets. The membrane devices may also be used in combination with a membrane and bone graft for Type 2 (labial plate dentoalveolar dehiscence defects) extraction socket reconstruction.

[0058] While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.