METHODS AND ARTICLES FOR TREATING PERIDONTAL DISEASE

Abstract: An article for treatment of periodontal disease. In use, the gingival tissue is separated from a tooth surface in an area where periodontal disease is present. A biocompatible, porous material (22) capable of supporting ingrowth of gingival connective tissue and preventing apical migration of gingival epithelium is placed in a laminar relationship to a portion of the perimeter of the tooth surface. The gingival tissue is repositioned around the tooth and in contact with the porous material, with the porous material positioned between the gingival tissue and the tooth. One preferred article comprises a first portion (22) which is capable of supporting ingrowth of gingival connective tissue and preventing apical migration of gingival epithelium and a second portion (24) which is impermeable to oral tissues.

Description: METHODS AND ARTICLES FOR TREATING PERIDONTAL DISEASE This application is a continuation-in-part application of Serial No. 628,308 filed July 6, 1984. BACKGROUND The present invention relates to methods and articles for treatment of periodontal disease, in particular to methods and articles for inhibiting periodontal pocket formation and healing periodontal defects. Periodontal disease is a disease of the periodontium, the tissues that invest and support the teeth as shown in Fig. 1. These tissues include: gingiva 1, the soft gum tissue of the mouth; gingival epithelium 2, the protective surface layer of the gingiva which seals against the tooth where the tooth passes into the oral cavity; the cementum (not designated in Fig. 1), a natu¬ ral adhesive covering the tooth root; alveolar bone 3, the bone of the jaw surrounding the tooth root; and the periodontal liga¬ ment 4, connective tissue which suspends and supports the tooth between alveolar bone and the tooth root. The gingival tissue surrounding a healthy adult tooth, as illustrated in Fig. 2, forms a sulcus 5 where it attaches to the tooth. In the early stages of periodontal disease, also known as gingivitis, bacteria in the sulcus infect and irritate surrounding gingiva. The bacteria .break down the attachment of the gingival epithelium to the tooth, forcing the epithelium to reattach apically (toward the root) away from infected tissue. Because the tissue is compromised by disease, the new attachment is weak. Further infection progressively moves the attachment apically until the tooth is surrounded by a loose sleeve of dis¬ eased gingiva creating a pocket which is much deeper than the normal sulcus. As depicted- in Fig. 3, the loose sleeve, called a periodontal pocket 6, is difficult to clean because a tooth brush and floss cannot reach the bacteria and plaque which accumulate within the pocket. As disease extends the periodontal pocket, the cementum, periodontal ligament, and supporting alveolar bone are destroyed, leaving a periodontal defect 7 filled with plaque and bacteria. Eventually the loss of the supporting periodontium leads to loss of the tooth. SUBSTITUTE SHEET Periodontal disease is the most common disease known to man. It. is reported in the literature that it affects 75 percent of the adult population and is the major reason for tooth loss after the age of 35, and that fifty-five million teeth are lost to the disease each year in the United States. Conventional treatment of periodontal defects consists of attempts to surgically alter the periodontal pocket morphology or obtain coronal (toward the crown) reattachment of the gingiva to the tooth. One prior art method alters the periodontal pocket morphology, creating a normally-shaped pocket at a site apical to the original attachment. This is accomplished by cutting away the coronal gingival tissue of a periodontal pocket and, if nec¬ essary, reshaping the underlying bone, to create a periodontal pocket similar in depth to a normal sulcus so that regular oral hygiene might be used to maintain the attachment of the gingiva to the tooth. This treatment does not recreate the cororidl at¬ tachment of gingiva to the tooth maintained before the diseased condition and does not replace periodontium lost to the disease. In another conventional treatment known as a gingival flap procedure, one or more flaps of gingival tissue are dis¬ sected away from the tooth. After the tooth is thoroughly cleaned by scaling or curetting, the flaps are reapposed to the cooth, sometimes incorporating gingival grafts from other por¬ tions of the mouth. However, reattachment of gingiva to a tooth surface that has been diseased is difficult to obtain using this procedure. Gingival epithelium migrates rapidly along the tooth root surface toward the apex of the tooth. Because bone and the periodontal ligament heal much more sLowly than the migrating epithelium, the epithelium often migrates apically back to the presurgical level, recreating a periodontal pocket similar in di¬ mension to the pocket before treatment. Although the flap proce¬ dure is commonly used by clinicians, it is mostly successful with three wall defects (referring to the number of boney walls left surrounding a defect), less successful with two wall defects, and not at all successful with one wall defects (Ellegaard, B. , Karring, T. and Loe, H. , "New periodontal attachment procedure based on retardation of epithelial migration," J. Clinical Periodontology 74:1:75-88) . U s-S3 ! _ i J _ -__ '--.i i______ 1 Historically, investigators have attempted to improve upon the treatment of periodontal disease by encouraging the at¬ tachment of gingival tissue to the tooth, speeding the healing of boney defects, or excluding gingival tissue from a healing defect site. By etching the tooth root surface with acids, some re¬ searchers have attempted to cause the gingival connective tissue (the highly vascular connective structure of the gingiva) to at¬ tach to the tooth, thus stopping the apical migration of gingival epithelium. Other researchers have attempted to fill boney de¬ fects with autogenous bone or artificial bone substitutes such as hydroxylapatite or tricalcium phosphate so that the boney portion of the defect might heal despite the rapid apical spread of epi¬ thelium. In another treatment, foils or other membranes into which gingival tissue cannot penetrate are used to separate the gingival tissue from the healing defect. In this method, the epithelium migrates apically- along one side of the membrane or foil, while the defect heals on the opposite side of the mem¬ brane. Previous attempts to correct periodontal defects with synthetic materials have not provided for the attachment of gin¬ gival tissue to the tooth while controlling the apical migration of epithelium. For this reason, these techniques have met with •only limited success. Ideally periodontal disease should be treated by obtaining an attachment of gingival tissue to the tooth which will halt the apical migration of epithelium near the level maintained before the disease. The defect apical to the gingival attachment can then be healed in by the appropriate pe¬ riodontal tissues. SUMMARY OF THE INVENTION The present invention, in one embodiment, provides a method for treatment of periodontal disease comprising: (a) separating the gingival tissue from a tooth surface in an area where periodontal disease is present; (b) fixing a biocompatible, porous material, capable of supporting ingrowth of gingival con¬ nective tissue and preventing apical migration of gingival epi¬ thelium, in a laminar relationship to (i.e. parallel and in inti¬ mate contact with) a portion of the perimeter of the tooth; and s UBJfflT- (c) repositioning the gingival tissue around the tooth and in contact with the porous material, with at least a portion of the porous material positioned between the gingival tissue and the tooth. The present invention further provides an article for the treatment of periodontal disease comprising a length of po¬ rous material capable of supporting ingrowth of gingival connec¬ tive tissue and preventing the apical migration of gingival epi¬ thelium, said length having a biocompatible, non-porous backing on a side capable of being placed in laminar relationship to a tooth surface. Additionally, the present invention provides an article for the treatment of periodontal disease comprising a po¬ rous material capable of supporting gingival connective tissue ingrowth and preventing apical migration of gingival epithelium, said length having at least one filament attached to each of two opposite ends serving to tie said porous material around a tooth. The invention involves placement of a porous material between the tooth surface and gingival tissue in an area in which periodontal disease has caused the attachment of the gingival epithelium to the tooth to migrate apically. Upon placement of the porous material in laminar relationship to a portion of the perimeter of the tooth surface, the gingival tissue is reposi- tioned around the tooth, resulting in the porous material being located between the gingival tissue and the tooth. During healing the porous material fills with gingival connective tissue thus halting the apical downgrowth of gingival epithelium. As such, the area which previously comprised the periodontal pocket fills in with healthy periodontal tissue. Moreover, it has been found that the use of an article wherein a first surface of the article is a porous material capa¬ ble of supporting the ingrowth of gingival connective tissue and preventing the apical migration of gingival epithelium and a sec¬ ond surface of the article is impermeable to oral tissues in a method similar to that set forth above also results in successful treatment of periodontal disease. Thus, the present invention also provides a method for the treatment of periodontal disease comprising: (a) temporarily separating the gingival tissue from a tooth surface in an area where periodontal disease is present; (b) fixing an article in a laminar relationship to a portion per¬ imeter of a tooth surface, wherein the article comprises a member having first and second juxtaposed surfaces meeting at a boundary wherein the boundary is capable of at least partially encircling the perimeter of the tooth to be treated, said first surface com¬ prising a porous, biocompatible material capable of supporting the ingrowth of gingival connective tissue and capable of pre¬ venting the apical migration of gingival epithelium, said first surface further configured so as to surround a portion of the perimeter of the tooth immediately apical to the desired sulcus line with the porous surface abutting the gingival connective tissue, and said second surface being impermeable to oral tissues and configured so as to surround at least a portion of the perim¬ eter of the tooth apical to the first surface, said second sur¬ face positioned so that after healing at least a portion of the first surface is exposed to gingival epithelial tissue in the area of the desired sulcus line and said second surface abutting the gingival connective tissue and (c) reattaching the gingival tissue around the tooth and in contact with the article. For use in the method of this latter embodiment, the present invention also provides an article for the treatment of periodontal disease by promoting gingival tissue attachment . about a desired sulcus line. The article comprises a member having first and second juxtaposed surfaces meeting at a boundary where¬ in said boundary is capable of at least partially encircling the perimeter of a tooth to be treated. The first surface is formed by a porous, biocompatible material capable of supporting ingrowth of gingival connective tissue and preventing the apical migration of gingival epithelium and configured so as to surround at least a portion of the perimeter of the tooth immediately api¬ cal to the desired sulcus line, with the porous surface abutting the gingival connective tissue. The said second surface is formed by a material impermeable to oral tissues and configured so as to surround at least a portion of the perimeter of the tooth apical to the first surfacae so that after healing the first surface is expσsed to gingival epithelial tissue in the OH i ~~ - , - - ■ - i^- - . ■ _ ■ _. --■ e-._ ", ■ _ Λ_Z" area of the desired sulcus line, the impermeable surface abutting the gingival connective tissue. Although the accompanying draw¬ ings show certain preferred shapes and geometries of the article of this invention, they are not to be taken to limit the scope of the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. Additional advantages of the invention will be set forth in part in the detailed description which follows, and in part will be obvious from the description or may be learned by practice of the invention. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate five exem¬ plary embodiments of the invention and, together with the de¬ scription, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a mesial-distal (parallel with jawbone ridge) cross-sectional view of a healthy adult tooth and peri¬ odontium. Figure 2 is a close-up view of the gingival sulcus of Figure 1. Figure 3 is a mesial-distal cross-sectional view of a periodontally diseased tooth with periodontal pocket and defect. Figure 4 is a mesial-distal cross-sectional view of the diseased tooth of Figure 3 repaired with the present invention. Figure 5 is a three-dimensional view of uniaxially ex¬ panded polytetrafluoroethylene. Figure 6 is a three-dimensional view of a first prefer¬ red embodiment of the article of the invention. Figure 7 is a three-dimensional view of a second pre¬ ferred embodiment of the article of the invention. Figure 8 is a three-dimensional view of a third prefer¬ red embodiment of the article of the invention. Figure 9 is a three-dimensional view of a fourth pre¬ ferred embodiment of the article of the invention wherein a first portion of the article is porous and a second portion of the article is impermeable to oral tissues. Figure 9A is a cross-sectional view of the fourth pre¬ ferred embodiment of Fig. 9 taken along line A-B. Figure 10 is a three-dimensional view of a fifth pre¬ ferred embodiment of the article of the invention wherein a first portion of the article is porous and a portion of the article is impermeable to oral tissues. Figure 10A is a cross-sectional view of the firth pre¬ ferred embodiment of Fig. 10 taken along line C-D. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are il¬ lustrated in the accompanying drawings. The present invention in part provides a method for treatment of periodontal disease which comprises: (a) separating the gingival tissue from a tooth surface in an area where periodontal disease is present; (b) fixing a biocompatible, porous material, capable of supporting ingrowth of gingival connective tissue and preventing apical migration of gingival epithelium, in a laminar relation¬ ship to a portion of the perimeter of the tooth; and (c) repositioning the gingival tissue around the tooth and in contact with the porous material, with at least a portion of the porous material positioned between the gingival tissue and the tooth. Preferably, a periodontally diseased tooth is prepared for repair by exposing all diseased portions of the tooth and pe¬ riodontium. For example, one or more buccal (toward cheek) or lingual (toward the tongue) flaps of gingiva can be reflected away from the tooth root and surrounding bone. The exposed de¬ fect can then be cleaned by conventional periodontic techniques such as scaling or curetting. Topical antibiotics may be applied to the diseased sites to discourage the population of bacteria. SUBSTΠ imϋriϊztzT The porous material is placed against the tooth surface and should extend coronally to the level at which repair of the defect is desired to occur. Preferably the porous material is placed to the level on the tooth just apical of where it is de¬ sired for the gingival epithelium (sulcus) to end. The porous material may be wrapped around the entire perimeter of the tooth. It is preferably placed around the por¬ tion of the tooth's perimeter where periodontal tissue attachment has been lost to disease. The porous material may be placed flat against the tooth surface. Preferably the porous material ex¬ tends out from the tooth surface to cover any boney defects sur¬ rounding the tooth. The porous material should be closely apposed to the tooth surface so that gingival epithelium cannot pass between the porous material and the tooth surface. The porous material may simply be placed between the gingival tissue and the tooth sur¬ face or it may be secured to the tooth surface . The porous material may be secured to the tooth surface by adhering the material to the tooth with suitable dental adhe- sives. A suitable dental adhesive is non-toxic to surrounding tissues, is capable of forming an adhesive bond in an open oral environment,- will remain for a sufficient amount of time to allow the defect to be repaired, and is capable of forming a bond be¬ tween a porous surface and a tooth surface. Dental adhesives in¬ clude, but are not limited to, zinc euginol, zinc phosphate, zinc silicophosphate, acrylic, glass ionomer, silicate and polycarboxylate cements . The porous material may also be secured in place around the tooth through the use of sutures or filaments . Sutures may . be used to lash the porous material to surrounding tissue and, thereby, hold it snugly against the tooth. Suture material may also be used to join the ends of porous material together to se¬ cure the porous material around the tooth. A filamentous mate¬ rial may be attached to the ends of the porous material and used to tie the porous material around the tooth. Such suture mate¬ rials or filamentous materials must be biocompatible, i.e. must be materials which do not adversely affect oral tissue. Additionally, the sutures or filamentous materials should not act as a conduit for bacterial invasion nor should they resorb until sufficient time has elapsed to allow periodontal tissues to fill in the defect. A preferred suture material, is Vicryl Suture available from Ethicon Incorporated. Gingival tissue is positioned against the porous mate¬ rial so that the porous material separates some portion of the gingiva from the tooth surface. The coronal portion of the por¬ ous material may extend coronal to the gingival tissue. Prefer¬ ably, as depicted in Fig. 4, the porous material 8 is completely covered with gingival tissue, leaving no portion of the porous material exposed to the oral cavity. The porous material may remain in the mouth for the life of the patient. Alternatively, the porous material may be removed after a time sufficient for the periodontal tissues to fill the defect and attach to the tooth surface. The porous material should be made from biocompatible materials. The porous material must also allow for the rapid in¬ growth of gingival connective tissue to inhibit the apical migra¬ tion of gingival epithelium along the surface of the material. Preferably the porous material is soft and flexible so that it will conform to the curvature of the tooth and surrounding bone and not cause tissue necrosis in the tissues against which it is placed. Suitable biocompatible materials which can be made por¬ ous include, but are not limited to, silicones, polyurethanes, polyethylenes, polysulfones, polyacrylics, polycarboxylates, polyesters, polypropylenes, poly(hydroxyethylmerthacrylates) , and perfluorinated polymers, such as fluorinated ethylene propylene, and polytetrafluoroethylene. The above-mentioned may be made porous by any tech¬ niques known to those of ordinary skill in the art which will render the materials capable of supporting gingival connective tissue ingrowth while preventing apical migration of gingival epithelium. Such techniques include, but are not limited to, sintering carefully controlled sizes of beads; combining the materials with a partially resorbable implant that would resorb or could be resorbed, in vivo or in vitro, to leave a porous W< -I--.___J surface; weaving or knitting fibers together to form a fabric¬ like material; or using a foaming agent during processing to cause bubbles to form and leave pores as the material hardens. The porous material may be treated or filled with bio¬ logically active substances such as antibiotics, fibrin, thrombin, and collagen. These substances may enhance connective tissue formation within the porous material and inhibit infection during healing. The porous material may be backed with a non-porous material on the side of the porous material which juxtaposes the tooth surface. The non-porous material aids in retaining the open, porous structure of the porous material. The non-porous material would also aid in sealing the porous material against the tooth surface by conforming to the irregularities of the sur¬ face. Suitable non-porous materials include, but are not limited to, the porous materials listed above, and combinations thereof. The non-porous material can also be used to secure the porous material to the tooth surface by serving as a surface which bonds to a tooth-adhering adhesive. In this embodiment, a suitable dental adhesive, as set forth above, may be applied to the tooth or the non-porous side of the porous material before adhering the material onto the tooth. In another embodiment, one component of a multi-component adhesive may be incorporated into the non-porous material. The adhesive or the remaining compo¬ nents of the adhesive are introduced immediately before the mate¬ rial is adhered to the tooth. The porous material of the preferred embodiment is ex¬ panded polytetrafluoroethylene (expanded PTFE). Expanded PTFE is an extremely inert and biocompatible material with a history of medical implant use. U.S. Patent Numbers 3,953,566 and 4,187,390, the disclosures of which are incorporated herein by reference, teach methods for producing expanded PTFE and charac¬ terize its porous structure. The porous, structure of expanded PTFE is further illustrated in Figure 5. The microstructure of expanded PTFE is a three-dimensional matrix of nodes 9, connected by fibrils 10. The pore size of expanded PTFE can be characterized by determining the bubble point and the mean flow pressure of the material. Bubble point and mean flow pressure are measured according to the American Society for Testing and Materials Stan¬ dard F316-80 using ethanol. The density of expanded PTFE determines the amount of void space in the material which may become ingrown with connec¬ tive tissue. The density of expanded PTFE is the ratio of the mass of a given sample of expanded PTFE to its volume. The fibril length of expanded PTFE is defined herein as the average of ten measurements between nodes connected by fibrils in the direction of expansion. Although Figure 5 illus¬ trates material expanded in one direction only, PTFE expanded in more than one direction is thought to be equally applicable to the invention. In order to measure the average fibril length of expanded PTFE, two parallel lines are drawn across a photomicro¬ graph of about 40 to 50 times magnification of the surface of the material so as to divide the photograph into three equal areas. If the material has been uniaxially expanded, these lines are drawn in the direction of expansion (i.e. direction of orienta¬ tion of fibrils) . Measuring from left to right, five measure¬ ments of fibril length are made along the top line in the photo¬ graph beginning with the first node to intersect the line near the left edge of the photograph and continuing with consecutive nodes intersecting the line. Five more measurements are made along the other line from right to left beginning with the first node to intersect the line on the right hand side of the photo¬ graph. If the material is expanded in more than one direction, the lines are drawn and fibril lengths measured as above, except when a node is not attached by fibrils to a node intersecting the drawn line. In this case, the fibril length from the node to a node which creates the least angle with the drawn line is mea¬ sured along the fibril's axial orientation. The ten measurements obtained by this method are averaged to obtain the average fibril length of the material. Materials with average fibril lengths greater than about 60 microns, preferably greater than about 100 microns, SUBSTITUTESHEET ethanol bubble points of less than about 2.0 psi, preferably less than about 0.75 psi, ethanol mean flow pressure less than about 10 psi, preferably less than about 3.0 psi, and densities less than about 1 g/cc and preferably about 0.3 to about 0.1 g/cc en¬ hance connective tissue ingrowth and are therefore preferred for use in the present invention. When expanded PTFE is used as the porous material, it is preferred that a number of nodes 9 pass through the wall thickness of the expanded PTFE, as illustrated in Fig. 5, to pro¬ vide channels for tissue ingrowth and a wall resistant to crushing. Expanded PTFE without nodes passing through its wall thickness is more easily crushed by forces of mastication, there¬ by decreasing the pore size, increasing the density, and compro¬ mising ingrowth. Preferably, a majority of the nodes extend across the thickness dimension of the wall. In the preferred em¬ bodiments, an expanded PTFE gingival interface with a wall thickness of approximately Jj-lmm is used. The expanded PTFE may be of several configurations . Figure 6 illustrates one preferred "apron" configuration. The collar 11, of the apron is pulled snugly against the perimeter of the tooth, preferably by tying the ends 12 of the collar together with a pair of filaments 16 attached to ends 12 of the apron col¬ lar. The bib 13 of the apron is positioned coronally over boney defects adjacent to the tooth. Figure 7 illustrates another pre¬ ferred, "collar" configuration. The collar of expanded PTFE is pulled snugly against the perimeter of the tooth, preferably tying the ends 14 of the collar together using filaments not shown. Figure . 8 illustrates an additional preferred "patch" con¬ figuration. The notch 15 of the patch is placed snugly against the tooth, preferably by using suture material to lash the sides 16 of the patch to tissue surrounding the tooth. The present invention also provides an article for the treatment of periodontal disease comprising a length of a porous material capable of supporting ingrowth of gingival connective tissue and preventing apical migration of gingival epithelium, said length having a biocompatible, non-porous backing on one side capable of being placed in a laminar relationship to a tooth surface. This article preferably is shaped as the "apron" of Fig. 6, the "collar" of Fig. 7, or the "patch" of Fig. 8. The biocompatible, non-porous materials that comprise the backing are the same as those set forth above for use in the method for treatment of periodontal disease. The non-porous backing may serve as a surface for placement of an adhesive to secure the article to a tooth sur¬ face. Additionally, an adhesive component may be admixed with the non-porous backing to create a mechanical seal with the tooth surface when the article is used in the method of the present invention to treat periodontal disease. The present invention also provides an article for the treatment of periodontal disease comprising a length of porous material capable of supporting ingrowth of gingival connective tissue and preventing apical migration of gingival epithelium, said length having at least one filament attached to each of two opposite ends of the length. The filament can be used to secure the porous material to the tooth by tying the filaments around the tooth. As stated above, the filamentous material must be bio¬ compatible and should not serve as a conduit for bacterial inva¬ sion. Additionally, the filamentous material should not be resorbed until a sufficient time has elapsed for periodontal tis¬ sue to fill in the defect. The porous material may be shaped as a collar, a patch or an apron, as set forth in the previous embodiment. Prefer¬ ably, the porous material is shaped as an apron with the fila¬ ments serving as the "apron strings" as illustrated in Fig. 6. Preferably, the porous material is expanded PTFE as de¬ scribed above. The filamentous material is preferably an ex¬ panded PTFE suture material, as also described above. The filaments may be attached to the length of porous material by any method which provides an attachment capable of holding the porous material in place until sufficient ingrowth of periodontal tissue has occurred. Preferably, the filaments are tied or sewn to the porous material. If both the porous material and the filaments are comprised of expanded PTFE, the two may be joined by pressure and heat. „-__,._ „,, ,--=f SUBS a s i U a's- -. _-- <■ - * The present invention also provides an alternate method for the treatment of periodontal disease. In this alternate method, the gingival tissue is separated from a tooth surface in an area where periodontal disease is present. An article com¬ prising a member having first and second juxtaposed surfaces meeting at a boundary, wherein the boundary is capable of at least partially encircling the perimenter of a tooth to be treated and is fixed in a laminar relationship to a portion per¬ imeter of the tooth surface. The surface comprises a porous, bio¬ compatible material capable of supporting the ingrowth of gingi¬ val connective tissue and capable of preventing the apical migration of gingival epithelium. The first surface is configured so as to surround at least a portion of the perimenter of the tooth about the desired sulcus line with the porous sur¬ face abutting the gingival epithelial tissue. The second surface is impermeable to oral tissues and configured to surround at least a portion of the perimeter of the tooth apical to the de¬ sired sulcus. The second surface is further positioned so as to leave at least a portion of the first surface exposed to gingival epithelial tissue in the area of the desired sulcus line. The impermeable second surface is intended to abut the gingival con¬ nective tissues. Finally, the gingival tissues are repositioned around the tooth and in contact with the article, such that at least a segment of each of the first and second portions of the article are positioned between the gingival tissue and the tooth. Preferably the gingival tissues are repositioned so that the en¬ tire article is covered by gingival tissue. In the articles intended for use in this method, the porous materials of the first surface are contemplated to be sim¬ ilar to those discussed in detail in connection with the first method for treatment of periodontal disease discussed previously. In particular, it is preferred that the porous material be ex¬ panded PTFE. Materials with average fibril lengths greater than about 60 microns, preferably greater than about 100 microns, ethanol bubble points of less than about 2.0 psi, preferably less than about 0.75 psi, ethanol mean flow pressure less than about 10 psi, preferably less than about 3.0 psi, and densities less than about 1 g/cc and preferably about 0.3 to about 0.1 g/cc en¬ hance connective tissue ingrowth and are therefore preferred for use in the present invention. It is also preferred that a number of nodes pass through the wall thickness of the expanded PTFE. The second, impermeable surface of the article is in¬ tended to be a material which is impermeable to oral tissues but which may or may not be permeable to various body fluids. In this regard, if the material of the second portion is required to be permeable to any body fluids, it has been found that Gortex Surgical membrane material amiable from W.L. Gore & Associates performs satisfactorily. Various materials are contemplated for use in the con¬ struction of the second surface of the article. These materials include, but are not limited to, any of the porous biocompatible materials listed above made impermeable to oral tissues. It should be noted that the impermeable materials should be biocompatible in the sense that they do not cause inflammation of the oral tissues or react adversely with tissues to inhibit the healing process. In one embodiment, various lamination methods might be employed to join the second surface of the article to the first surface. Biocompatible adhesives including, but not limited to, polyurethanes or silicones may be used to join the two articles. In an alternate embodiment, porous materials suitable for the first surface might be rendered impermeable to oral tis¬ sues in areas desired for the second surface by either coating or filling the desired areas with, for example, silicones or urethanes or compressing the desired areas to make them less po¬ rous . In a preferred embodiment, expanded PTFE capable of supporting gingival connective tissue ingrowth is utilized for the first and second surfaces. To construct the second surface, the PTFE is rendered impermeable to tissue ingrowth in desired areas by the application of heat and pressure. In this embodi¬ ment, the porous expanded PTFE of the first surface is an inte¬ gral construction with the impermeable PTFE of the second sur¬ face. The second surface is preferably formed by the application SUBSTITUTE SHEET of plates heated between about 300 and 400°F and pressed against the porous expanded PTFE in the desired areas. In this embodi¬ ment, because the second surfaces is created by compressing the expanded PTFE of the first surface, no means for attachment of the first and second surface of the member are required. The articles for use in this alternate method are placed in the area of the periodontal defect as set forth above, with care being taken to ensure that the first, porous portion of the article is placed coronal to the second, impermeable portion. This article may be secured in the area of the defect, if so de¬ sired, with various biocompatible glues, sutures, filaments and the like as set forth above. Alternatively, either or both of the first and second surfaces of the articles used in conjunction with this alternate method may be backed with any of the variety of non-porous sub¬ stances previously disclosed as components of the articles used in practicing the first method. As noted above, such a backing will serve to retain the open structure of the porous material of the first portion of the article end may assist in the securing of the articles into the area of the defect. The advantage of this second method is that the article may be removed easily. After desired healing of periodontal tis¬ sue has taken place, the first surface of the article, which is ingrown with connective tissue and has stopped the apical migra¬ tion of epithelium, is separated from the gingiva. The second surface of the article can then be removed easily, as it is im¬ permeable to tissue ingrowth. It is generally contemplated that the article of this method will be removed from the perimeter of the tooth at about four weeks after implantation, although the article may be re¬ moved at any time the desired periodontal structures have regen¬ erated. The article may also be kept in place indefinitely. The article inhibits apical migration of gingival epithelium while allowing regeneration of healthy periodontal tissue within the defect. Upon removal of the article, it is believed that peri¬ odontal structures will have regenerated sufficiently to provide improved periodontal health for the tooth. _ ~ - %f-l ~ _-- \_ ~ _- ~ T 1 It is envisioned that the article contemplated for use in this method may be of a variety of constructions. In general, this article is a method for the treatment of peridontal disease comprising: (a) temporarily separating the gingival tissue from a tooth surface in an area where periodontal disease is present; (b) fixing an article in a laminar relationship to a portion per¬ imeter of a tooth surface, wherein the article comprises a member having first and second juxtaposed surfaces meeting at a boundary wherein the boundary is capable of at least partially encircling the perimeter of the tooth to be treated, said first surface com¬ prising a porous, biocompatible material capable of supporting the ingrowth of gingival connective tissue and capable of pre¬ venting the apical migration of gingival epithelium, said first surface further configured so as to surround a portion of the perimeter of the tooth about the desired sulcus line with the po¬ rous surface abutting the gingival epithelial tissue, and said second surface being impermeable to oral tissues and configured so as to surround at least a portion of the perimeter of the tooth apical to the desired sulcus line, said second surface po¬ sitioned to leave at least a portion of the first surface exposed to gingival epithelial tissue in the area of the desired sulcus line and said second surface abutting the gingival connective tissue and (c) repositioning the gingival tissue around the tooth and in contact with the article, with at least a segment of the first portion of the article positioned to lie between the gingival tissue to be reattached and the tooth. This article may be of laminar or integral construction, as noted above. Two preferred embodiments of this article are shown in Figs. 9 and 10. In Fig. 9, the article has a "poncho" shape. In this embodiment, the center 18 of the poncho forms the first, po¬ rous surface and the outer circumference 20 of the poncho forms the second, impermeable surface. A slit 22 or hole may be ren¬ dered in the first portion 18 of the article so that the article may be placed over the tooth with portion 18 surrounding the per¬ imeter of the tooth in the area of the desired sulcus line. In the alternate embodiment of Fig. 10, the article has an apron shape suitable for forming into a collar wherein the Sn• ____*•_»__•T-ii.T5i - " n) i"££_.: " j _ ■ j___..£ ^™£ηjr first, porous surface 22 of the article and the second, imperme¬ able surface 24 of the article are depicted. When the article as shown in Fig. 10 is used in the above method, suture material 16 may be used to secure the article around the perimeter of the tooth. All articles of the present invention are preferably sterilized prior to insertion into a periodontal pocket. Prefer¬ ably, the articles are sterilized and are contained in a package, the interior environment of which is sterile. The following examples were designed to elucidate the teachings of the present invention, and not to limit the scope of the invention. Various other modifications and equivalents of the examples will readily suggest themselves to those of ordinary skill in the art, particularly after issuance of this patent, without departing from the spirit or scope of the present inven¬ tion. Example 1 Expanded PTFE aprons similar to those illustrated in Figure 6 were implanted in dogs. Historically, dogs have been used to test periodontal techniques and materials (Lindhe, J. and Rylander, H. , "Experimental Gingivitis in Young Dogs", Scand. J. Dent. Res. 83:314-326; Hilding, B., "Experimental Studies on Re¬ attachment", Dental Practitioner, Vol. XI, No. 10, 351-354; Ririe, CM., Crigger, M. and Selvig, K.A., 1980 "Healing of peri¬ odontal connective tissue following surgical wounding and appli¬ cation of citric acid in dogs" J. Periodontal Res. 15:314-327; Crigger, M. , Bogle, G. , Nilveus, R. , Egelberg, J. and Selvig, K.A., 1978 "The effect of topical citric acid application on the healing of experimental furcation defects in dogs" J. Periodontal Research. 13:538-549). The expanded PTFE for the aprons was made according to the description in Patent Numbers 4,187,390 and 3,953,566 as fol¬ lows: A mixture of PTFE resin in a liquid lubricant was extruded into a tubular form. The extruded tubular form was dried for approximately 96 hours at about 300°C, which removed the lubri¬ cant. The tubular form, held at a temperature of about 295°C, was then stretched at a constant velocity along the central axis SUBSTITUTE SHEET of the tube at a rate of about 75% per second until it was approximately 10 times its original length, where rate was de¬ fined as ■ifϊT t r x ιoo%- and If = final length, li = initial length, and t = total time of expansion. Subsequent to stretching, the tube was restrained longitudinally and heat treated at about 375 °C for about 75 sec¬ onds. The expanded PTFE tube was then slit longitudinally through its wall and laid flat. The wall was about 1mm thick and had nodes passing through its wall thickness. The ethanol bubble point of the material was about 0.5 psi and the ethanol mean flow pressure was about 1.0 psi. The average fibril length was about 200 microns, and the density was approximately 0.2 g/cc. The bib and collar portion of the apron were cut from the expanded PTFE so that the collar was about 2cm long and 2mm wide, and the bib extended out from the collar about a centime¬ ter. A 6-0 GORE-TEX® Expanded PTFE Suture filament, obtained from W.L. Gore & Associates, Flagstaff, Arizona, was passed through each end of the apron collar. All assembly of the apron took place in a clean room environment. The apron was sterilized prior to implantation. At implantation, buccal and lingual periosteal flaps were reflected around dog premolar teeth. About 2mm of crestal bone was removed circumferentially from the teeth to expose a root surface against which the aprons could be applied. Either a three wall mesial defect or a one wall buccal defect was created adjacent to the teeth using burrs and chisels. The collar of the apron was placed around the perimeter of the tooth with the bib positioned coronally over the created boney defect. The ends of the GORE-TEX® Expanded PTFE sutures were then tied together on the side of the tooth opposite the defect drawing the ends of the collars together and tightening the apron around the tooth. Any excess suture was trimmed off, and the gingival flaps were repositioned over the apron by suturing them in place. A total of five implants were placed in two dogs. m. . -mrnrn. Λ J _ « ■ "• J"" "-J" SUE o * UTϋ oncc i Beginning one week after surgery the implant sites were assessed clinically. After initial healing, probing revealed in all cases a healthy appearing gingiva attached to the apron forming a 2 to 3mm deep, normal appearing sulcus. In one case, a small portion of the apron was inadvertently left exposed to the oral cavity, but all surrounding tissue appeared healthy and healed into the remainder of the apron. Two implants, including the above mentioned case, were harvested at 20 and 30 days and assessed histologically. The ex¬ panded PTFE collar and bib, in all areas except that exposed to the oral cavity, appeared filled with connective tissue. Epi¬ thelium apparently halted its apical migration at or directly coronal to the expanded PTFE, and new bone had filled the created defects . Example 2 Expanded PTFE collars as illustrated in Figure 7 backed with medical grade silicone and polyurethane were implanted in dogs. The medical grade silicone, obtained from Dow-Corning Cor¬ poration, and polyurethane, Cardiomat™ 610 obtained from Kontron Cardiovascular Inc., were applied to the expanded PTFE as a thin backing and allowed to cure. The expanded PTFE had an ethanol bubble point below about 0.75 psi, an ethanol mean flow pressure below about 3 psi, an average fibril length greater than about 100 microns, a density of about 0.3 to- 0.1 g/cc, and a wall thickness of about 1mm. The backed, expanded PTFE was cut into strips (collars) approximately 2mm wide and 2cm long. The collars were sterilized and implanted in premolar sites according to the procedure detailed in example 1 without creating defects. The silicone or polyurethane backed side of the collars was placed against the tooth, and each collar was secured around a tooth by tying its ends together with GORE-TEX® Expanded PTFE Suture. Four implants were retrieved between 19 and 32 days after surgery for histolog- ical analysis. Probing of the implants prior to retrieval revealed a normal appearing sulcus with no inflammation and gingiva attached to the collar. Microscopic examination of the implant revealed SU rΑTiYi ΓΓF C • _ , - - ~τ that the polyurethane and silicone backings were in most places directly apposed to the tooth root. The expanded PTFE had filled with connective tissue, and the gingival epithelium had attached to the connective tissue within the collar, apparently halting its apical migration. Example 3 Expanded PTFE with a urethane backing was adhered to dog teeth using a conventional glass iono er dental cement. The expanded PTFE had an ethanol bubble point below about 0.75 psi, an ethanol mean flow pressure below about 3 psi, an average fibril length greater than about 100 microns, a density of about 0.3 to 0.1 g/cc, and a wall thickness of about 1mm. It was backed with a mixture of glass ionomer powder, Chembond® Glass Ionomer Cement obtained from the L.D. Caulk Company, and liquid urethane, Cardiomat™ 610 Polymer. About 1.2cc of the urethane was mixed with about 1 gram of the powder and spread in a thin coating " on one side of the expanded PTFE. The backing was allowed to cure for about 24 hours. The backed, expanded PTFE was sterilized. A small piece of the backed material approximately 1cm x 0.5cm was adhered to the right maxillary canine root in a dog. After a gingival flap had been reflected, the glass ionomer ce¬ ment was mixed according to the manufacturer's instructions and placed on the root. The backed side of the expanded PTFE was pressed into the cement before the cement had cured, and any ex¬ cess cement was removed. After the adhesive had cured, the gin¬ gival flap was repositioned over the expanded PTFE and sutured in place. Approximately one month after surgery, the implant was retrieved. Microscopic examination revealed that the backing had not remained completely attached to the tooth but that the ex¬ panded PTFE had filled with healthy, vascularized connective tis¬ sue. Gingival epithelium appeared to be attached to the connec¬ tive tissue, apparently halting epithelial apical migration. Example 4 An apron like that described in Example 1 and two col¬ lars like those described in Example 2 were backed with a thin UtJaJJ 5 8 ; i -*_. - - _t J »t__ . line of either silicone or urethane elastomer. Approximately 0.5mm wide lines of Cardiomat™ 610 Urethane or Dow Corning medi¬ cal grade silicone were forced from a syringe onto the expanded PTFE along the length of collar. The lines were placed on the side of the collar meant to fit against the tooth. The expanded PTFE collar was held slack to about 75% of its fully extended length during the application of the elastomer so that after the collar was stretched around the tooth and the ends of the collar tied together with sutures, the elastomer held the collar against the tooth as an elastic waistband holds trousers against the waist. Each implant was sterilized and implanted in premolar sites in a dog with the bib of the apron covering a defect as de¬ scribed in Example 1 and the collars placed in sites with no de¬ fects. In all cases after an initial week of healing, probing revealed healthy appearing gingiva attached to the expanded PTFE forming a normal appearing sulcus adjacent to the tooth. Histological analysis showed the epithelium apparently halting its apical migration at or directly coronal to expanded PTFE filled with connective tissue. New bone had healed in the defect apical to the apron. Example 5 Expanded PTFE was cut into small patches approximately 12mm x 12mm as illustrated in Figure 8. The patches had an ethanol bubble point below about 0.75 psi, an ethanol mean flow pressure below about 3 psi, an average fibril length greater than about 100 microns, a density of about 0.3 to 0.1 g/cc, and a wall thickness of about 1mm. After gingival flaps had been reflected, three wall mesial defects were created adjacent to the roots of two first molars in one dog and the fourth premolar in the mandi¬ ble of another dog. The patches were fitted over the boney de¬ fects and conformed to the boney ridge with the root of the treated tooth resting in the notch of the patch. The gingival flaps were repositioned over the patches and sutured in place. The molar implants were retrieved 19 and 20 days after surgery, and the premolar implant was retrieved 30 days following surgery. ' SI I &d>!IT «5» In all sites approximately 2mm of expanded PTFE re¬ mained exposed to the oral cavity adjacent to the mesial aspect of the treated teeth. Histologiσal analysis revealed that gingi¬ val tissue had filled a space between the notch of the patch and the tooth. New bone had filled the defects, and the patches had apparently inhibited the growth of gingival tissue into the de¬ fect space. The portions of expanded PTFE which had not become exposed to the oral environment were healed in with healthy, vascularized connective tissue. Epithelium had apparently halted its apical migration at the interface between the exposed and healed portions of expanded PTFE. This treatment method was somewhat unsuccessful because gingival tissue managed to grow between the patch and the tooth surfaces. It may be possible to appose the notch of such a patch more tightly against the tooth by lashing the patch to adjacent tissue with sutures or by other suitable means. Such a patch might enable a normal sulcus to be formed around the tooth with¬ out the formation of gingival tissue between the patch and tooth or the exposure of the patch to the oral cavity. The boney de¬ fect would be filled in by the appropriate tissues of the peri¬ odontium as demonstrated in the example. Example 6 Expanded PTFE was adhered to a tooth using acrylic ce¬ ment. The expanded PTFE had an ethanol bubble point below about 0.75 psi, an ethanol mean flow pressure below about 3 psi, an av¬ erage fibril length greater than about 100 microns, a density of about 0.3 to 0.1 g/cc, and a wall thickness of about 1mm. Con¬ cise® and Silar® cements were used as supplied by Dental Prod- ucts/3M. After buccal gingival flaps had been reflected from the maxillary canine of a dog, the exposed root was notched approxi¬ mately 0.5mm deep and 2mm wide directly coronal to the bone sur¬ rounding the root from the mesial to the distal aspect of the ex¬ posed root. Silar® paste mixed according to the manufacturer's instructions was then used to fill the notch. A strip of the expanded PTFE, which had been steril¬ ized, was cut approximately 2mm wide and long enough to extend from the mesial to the distal aspect of the exposed root. Con¬ cise® resin liquids were mixed with Concise® paste components forming a paste which could be spread and adhered on one side of the expanded PTFE strip. The pasted side of the expanded PTFE strip was placed against the Silar® filled notch on the root. The adhesive was allowed to set, and the gingival flap was repositioned over the expanded PTFE strip and sutured in place. After 40 days the implant was retrieved. The expanded PTFE strip appeared well attached to the tooth. Epithelium appeared to end against the expanded PTFE, but gingival tissue surrounding and within the expanded PTFE exhibited an apparent adverse reaction to the adhesive. An adhesive system which would bond an expanded PTFE strip to the tooth and which would be biocompatible with the oral tissue would be a more viable treatment modality. Example 7 Ponchos and aprons, as illustrated in Figures 9 and 10, were made by laminating two structures of expanded PTFE. GORE- TEX® expanded PTFE Surgical Membrane of 0.1 mm thickness obtained from W. L. Gore & Associates, Incorporated was cut into 40 x 25 mm rectangles to form the portion of the ponchos and aprons im¬ permeable to tissue ingrowth. Expanded PTFE, capable of sup¬ porting the ingrowth of gingival connective tissue and preventing the migration of gingival epithelium, was cut into smaller rec¬ tangles, either 10 x 20 mm, 8 x 20 mm, or 5 x 20 mm. These smaller rectangles of expanded PTFE had an ethanol bubble point below about 0.75 psi, an ethanol mean flow pressure below about 3 psi, an average fibril length greater than about 100 microns, a density of about 0.3 to 0.1 g/cc, and a wall thickness of about 0.5 mm. The smaller rectangles were laminated to the Surgical Membrane in roughly the center of the Surgical Membrane rectangles using a thin layer of either biocompatible urethane or silicone adhesive placed between the two expanded PTFE structures. The biocompatible silicone adhesive was obtained from Dow Corning Corporation, and the biocompatible urethane adhesive was a segmented polyether polyurethane obtained from Ethicon Incorporated. SUBSTITU E SHEET After the adhesive had cured, the ponchos and aprons were steam sterilized in preparation for implantation in dogs. During surgery, buccal and lingual periosteal flaps were re¬ flected around dog premolar teeth. Up to 7 mm of crestal bone, ligament and cementum were removed to create horizontal defects with, furcation involvement. The aprons or ponchos were implanted with the surgical membrane material trimmed to cover the prepared defects. The gingival flaps were repositioned over the implanted material by suturing the flaps in place. Shaping of the pieces into either ponchos or aprons took place at the time of surgery by using scalpel or sharp scis¬ sors. If a poncho was to be implanted, a slit was made through the laminate within the area of smaller rectangle of expanded PTFE. The slit was sized to fit over the crowns of the dogs' teeth and fit snugly around the tooth below the cemento-enamel junction (CEJ). The expanded PTFE capable of supporting the ingrowth of gingival connective tissue formed a collar around the tooth coronal to the Surgical Membrane portion which formed a skirt covering the defect. Aprons were formed by cutting a col¬ lar shape out of the smaller expanded PTFE rectangle and a bib shape out of the surgical membrane portion. The collar portions had extended tabs which were wrapped around the circumference of the tooth and drawn together against the tooth by means of absorbable suture. The collars (capable of supporting gingival connective tissue ingrowth) were placed coronal to the bib por¬ tion of the aprons which covered the defects . Approximately 20 to 30 days after surgery, a small in¬ cision around the teeth or, in some cases, a split thickness flap was used to separate tissue which had ingrown into the portion of the implants capable of supporting gingival connective tissue ingrowth. The entire implants, including collars and Surgical Membrane, were removed, and gingival tissue was reapposed to the tooth with suture where necessary. Of eight teeth implanted, two were removed at 37 days, one was removed at 49 days, and one was removed at 61 days post- surgery for microscopic examination. The remaining implants re¬ mained _in vivo for clinical evaluation. . SUSSTST' T-Ξ SHEET All implant sites showed no sign of inflammation and displayed normal sulcus depths. There were no gingival pockets or other signs of apical epithelial migration. The teeth were all immobile. In one case, a tooth that had been made mobile by defect creation at the time of surgery became immobile after healing — evidence that periodontium had regenerated to support the tooth. It will be apparent to those skilled in the art that various modifications and variations can be made in the processes of the present invention. Thus, it is intended that the present invention cover the modifications and variations of this inven¬ tion provided that they come within the scope of the appended claims and their equivalents.

Claims: AMENDED CLAIMS [received by the International Bureau on 6 January 1986 (06.01.86) ; original claims 1-30 unchanged; new claims 31-68 added (6 pages) ] 31. (new) A method for treatment of periodontal disease comprising: (a) temporarily separating the gingival tissue from a too surface in an area where periodontal disease is present; (b) fixing an article comprising on at least one surface biocompatible, porous material capable of supporting ingrowth o gingival connective tissue and preventing apical migration of gingival epithelium in a laminar relationship to a portion of t perimeter of the tooth about the desired sulcur line, said arti cle positioned so as to leave said at least one surface of the article exposed to the gingival connective tissues; and (c) repositioning the gingival tissue around the tooth an in contact with said article, with at least a portion of said article positioned to lie between the gingival tissue to be reattached and said tooth. 32. (new) The method of claim 31 wherein said biocompatible, porous material is selected from the group con¬ sisting of silicones, polyurethanes, polyethylenes, polysulfone polyacrylics, polycarboxylates, polyesters, polypropylenes, pol (hydroxyethyl ethacrylates) and perfluorinated polymers. 33. (new) The method of claim 31 wherein said porous mat rial is expanded polytetrafluoroethylene. 34. (new) The method of claim 33 wherein said polytetra¬ fluoroethylene has an average fibril length of greater than abo 60 microns, an ethanol bubble point of less than about 2.0 psi, an ethanol mean flow pressure of less than about 10 psi and a density of less than about 1 g/cc. 35. (new) The method of claim 34 wherein said polytetra¬ fluoroethylene has an average fibril length of greater than abo 100 microns, an ethanol bubble point of less than about 0.75 ps an ethanol mean flow pressure of less than about 3.0 psi and a density of about 0.3 to about 0.1 g/cc. 36. (new) The method of claim 31 wherein said article co tains a surface which comprises a biocompatible, non-porous mat rial. 37. (new) The method of claim 36 wherein said biocompatible, non-porous material is silicone. 38. (new) The method of claim 36 wherein said biocompat¬ ible, non-porous material is polyurethane. 39. (new) The method of claim 31 wherein said article is secured to the tooth surface by wrapping said article around th tooth and securing said article with sutures. 40. (new) The method of claim 31 wherein said article is secured in the periodontal pocket by lashing said article to th surrounding gingival tissue with sutures. 41. (new) The method of claim 31 wherein said article ha at least one filament attached to each of at least two opposite ends, which filaments are used to tie said porous material arou said tooth. 42. (new) The method of claim 39, 40 or 41 wherein said sutures and filaments are expanded polytetrafluoroethylene. 43. (new) The method of claim 31 wherein said article is in the shape of an apron. 44. (new) The method of claim 31 wherein said article is in the shape of a collar. 45. (new) The method of claim 31 wherein said article is in the shape of a patch. 46. (new) The method of claim 31 wherein a topical antib otic is applied to the article prior to placement of the articl 47. (new) The method of claim 31 wherein a biologically active substance is incorporated into said article. 48. (new) The method of claim 36 wherein said non-porous material contains an adhesive component. 49. (new) The method of claim 48 wherein said adhesive component comprises a glass ionomer powder and urethane. 50. (new) The method of claim 31 wherein the diseased gingival and epithelial tissue is removed prior to fixing said article to said tooth. 51. (new) An article for the treatment of periodontal di ease comprising a length of porous material capable of supporti ingrowth of gingival connective tissue and preventing the apica migration of gingival epithelium, said length having a biocompatible, non-porous backing on a side capable of being placed in a laminar relationship to a tooth surface. 52. (new) The article of claim 51 wherein said porous material is expanded polytetrafluoroethylene. 53. (new) The article of claim 52 wherein said polytetra fluoroethylene has an average fibril length of greater than abo 60 microns, an ethanol bubble point of less than about 2.0 psi, an ethanol mean flow pressure of less than about 10 psi and a density of less than about 1 g/cc. 54. (new) The article of claim 53 wherein said polytetra fluoroethylene has an average fibril length of greater than abo 100 microns, an ethanol bubble point of less than about 0.75 ps an ethanol mean flow pressure of less than about 3.0 psi and a density of about 0.3 to about 0.1 g/cc. 55. (new) The article of claim 51 wherein said non-porou backing is polyurethane. 56. (new) The article of claim 51 wherein said non-porou backing is silicone. 57. (new) An article for the treatment of periodontal di ease comprising a length of porous material capable of supporti ingrowth of gingival connective tissues and preventing apical m gration of gingival epithelium,- said length having at least one filament attached to each of at least two opposite ends. 58. (new) The article of claim 58 wherein said porous material is expanded polytetrafluoroethylene. 59. (new) The article of claim 58 wherein said polytetra fluoroethylene has an average fibril length of greater than abo 60 microns, an ethanol bubble point of less than about 2.0 psi, an ethanol mean flow pressure of less than about 10 psi and a density of less than about 1 g/cc. 60. (new) The article of claim 59 wherein said polytetra fluoroethylene has an average fibril length of greater than abo 100 microns, an ethanol bubble point of less than about 0.75 ps an ethanol mean flow pressure of less than about 3.0 psi and a density of about 0.3 to about 0.1 g/cc. 61. (new) The article of claim 57 wherein said article h a nonporous backing on a side capable of being fixed in a lamin relationship to a tooth surface. 62. (new) The article of claim 57 wherein said filaments are expanded polytetrafluoroethylene. 63. (new) The article of claim 51 or 57 wherein said length s in the shape of a collar. 64 (new) The article of claim 51 or 57 wherein said length s in the shape of a patch. 65 (new) The article of claim 51 or 57 wherein said length is in the shape of an apron. 66 (new) The article of claim 51 or 57 wherein said ar cle has been sterilized and is contained in a package, the int rior environment of which is also sterile. -36- 67. (new) An article of manufacture for use in prostheti implants capable of supporting preferential tissue ingrowth, th article comprising a sintered porous polytetrafluoroethylene me ber having first and second juxtaposed surfaces meeting at a boundary, said first surface for supporting tissue ingrowth and said second surface for preventing tissue ingrowth, wherein the portion of said porous member portion defining said second sur¬ face is compressed relative to the member portion defining said first surface. 68. (new) The article as in claim 67 wherein said sinter porous member is continuous across said boundary. Statement Under Article 19(1) The added claims are directed to an article comprising at least one porous surface. These claims differ fro the origin claims in that the original claims were directed to an article having at least one porous surface and one impermeable surface juxtaposed to the porous surface.

Inventors: AMBRUSTER JEANNE B, DAVIDSON DANIEL F, MOTSINGER SUZANNE, SCANTLEBURY TODD V, AMBRUSTER, JEANNE, B., DAVIDSON, DANIEL, F., MOTSINGER, SUZANNE, SCANTLEBURY, TODD, V.
Applicants: GORE & ASS, W.L. GORE & ASSOCIATES, INC.
Application year: 1985
Main classification: A61C8
IPC codes: A61C5, A61C8, A61C19, A61K6, A61K9