Calcium aluminate based paste for stabilizing dental implants and restoring tissue attachment after surgery and methods therefore

Abstract

The present invention relates to a calcium aluminate based paste forming a chemically bonded biomaterial on hydration thereof for in vivo anchoring of new implants, or stabilizing of existing implants in situ to an adjacent bone tissue, which paste provides a controlled pH value and temperature as well as initial hardening time. By virtue of the pH value and temperature the paste exhibits antibacterial and/or bacteriostatic properties. The present invention also relates to a method of preparing implants to be implanted wherein the implant is coated with the paste, a method of implanting a coated implant, as well as methods of preventing and treating implant related conditions, such as periimplantitis, and a kit for preparing the paste. The invention is especially intended for re-stabilization of dental implants, and implantation into low quality bone tissue.

1 . A calcium aluminate based paste forming a chemically bonded biomaterial on hydration thereof obtainable by mixing:
 a powder comprising a powdered cement and optionally, inert filler particles, which cement is based on calcium aluminate; and   an aqueous hydration liquid containing LiCl, characterised in that the calcium aluminate consists of particles of the phases CA and/or C 12 A 7 , and optionally C 3 A, wherein the cement may additionally comprise the calcium silicate phase C 3 S, and wherein the combined amounts of any C 3 A and C 3 S present do not exceed 10% by weight of the cement, and in a mean particle size of the powdered cement within the interval of 2-7 μm, and in that the powder to liquid ratio is within the range of 2.0:1 to 5.0:1.   
     
     
         2 . The paste of  claim 1 , characterised in that the hydration liquid comprises 98-100 wt-% of deionized water and 10-200 mM of LiCl, and preferably also 0.2-2.0 wt-% of a Ca 2+  scavenging chelating agent. 
     
     
         3 . A method of preparing an implant suitable for implantation into low quality bone tissue comprising the following steps:
 providing a powder comprising a powdered cement and optionally, inert filler particles, which cement is based on calcium aluminate;   providing an aqueous hydration liquid containing LiCl; and   mixing the powdered cement and hydration liquid so as to form a paste;   
       characterized in the further step of
 applying the paste thus formed to a surface of an implant, which surface is to be in contact with bone tissue, and in that the calcium aluminate consists of particles of the phases CA and/or C 12 A 7 , and optionally C 3 A, wherein the cement may additionally comprise the calcium silicate phase C 3 S, and wherein the combined amounts of any C 3 A and C 3 S present do not exceed 10% by weight of the cement, and in a mean particle size of the powdered cement within the interval of 2-7 μm, and in that the powder to liquid ratio is within the range of 2.0:1 to 5.0:1. 
 
     
     
         4 . The method of  claim 3 , comprising the further step of treating the implant surface with an aqueous solution of C 3 S, CaO and/or C 3 A before applying the paste to said surface. 
     
     
         5 . The method of  claim 3 , wherein the total volume of paste applied to the implant is less than 0.8 cm 3 , and preferably less than 0.5 cm 3 . 
     
     
         6 . (canceled) 
     
     
         7 . A method of implantation, which method is suitable for implanting a dental implant into low quality bone tissue comprising the following steps:
 providing a powder comprising a powdered cement and optionally, inert filler particles, which cement is based on calcium aluminate;   providing an aqueous hydration liquid containing LiCl; and   mixing the powdered cement and hydration liquid so as to form a paste; also comprising the further steps of   applying the paste to a surface of an implant, which surface is to be in contact with bone tissue, and/or filling the paste into a pre-drilled hole in the bone tissue into which hole the implant is to be inserted; and   implanting the coated implant into the bone tissue;   
       wherein the calcium aluminate consists of particles of the phases CA and/or C 12 A 7 , and optionally C 3 A, wherein the cement may additionally comprise the calcium silicate phase C 3 S, and wherein the combined amounts of any C 3 A and C 3 S present do not exceed 10% by weight of the cement, and wherein the powdered cement exhibit a mean particle size within the interval of 2-7 μm, and the powder to liquid ratio is within the range of 2.0:1 to 5.0:1. 
     
     
         8 . The method of  claim 7  further comprising the step of treating said implant surface and/or said pre-drilled hole with an aqueous solution of C 3 S, CaO and/or C 3 A before applying the paste to said surface, and before filling the paste into said pre-drilled hole, respectively. 
     
     
         9 . The method of  claim 7  for preventing an implant related medical condition, such as periimplantitis, in a subject in the need of an implant. 
     
     
         10 . A method of in situ re-stabilizing an existing implant in bone tissue in a subject, which method is suitable for re-stabilizing a dental implant in low quality bone tissue, comprising the following steps:
 providing a powder comprising a powdered cement and optionally, inert filler particles, which cement is based on calcium aluminate;   providing an aqueous hydration liquid containing LiCl; and   mixing the powdered cement and hydration liquid so as to form a paste; also comprising the further step of   applying the paste to a surface of an existing implant in need of re-stabilization in bone tissue in a subject, which surface is to be in contact with bone tissue;   
       wherein the calcium aluminate consists of particles of the phases CA and/or C 12 A 7 , and optionally C 3 A, wherein the cement may additionally comprise the calcium silicate phase C 3 S, and wherein the combined amounts of any C 3 A and C 3 S present do not exceed 10% by weight of the cement, and wherein the powdered cement exhibit a mean particle size within the interval of 2-7 μm, and the powder to liquid ratio is within the range of 2.0:1 to 5.0:1. 
     
     
         11 . The method of  claim 10  further comprising the step of treating said implant surface with an aqueous solution of C 3 S, CaO and/or C 3 A before applying the paste to said surface. 
     
     
         12 . The method of  claim 10  for in situ treatment of an implant-related illness, such as periimplantitis, in a subject wearing one or more dental implants. 
     
     
         13 . The method of  claim 7 , wherein the pH interval during hydration is controlled to be within the interval of 8.5-12.5, the temperature is controlled to be within the interval of 37-60° C., and the hydration time is controlled to be within the range of 5-60 minutes. 
     
     
         14 . The method of  claim 3 , wherein the total volume of paste applied to the implant is less than 0.8 cm 3 , and preferably less than 0.5 cm 3 . 
     
     
         15 . The paste of  claim 1  for use in preventing and/or treating an implant related disease, such as periimplantitis. 
     
     
         16 . A kit for use in preparing the paste of  claim 1 , comprising:
 a powder comprising a powdered cement and optionally, inert filler particles, which cement is based on calcium aluminate, characterized in that the calcium aluminate consists of particles of the phases CA and/or C 12 A 7 , and optionally C 3 A, wherein the cement may additionally comprise the calcium silicate phase C 3 S, and wherein the combined amounts of any C 3 A and C 3 S present do not exceed 10% by weight of the cement, and in a mean particle size of the powdered cement within the interval of 2-7 μm; and an aqueous hydration liquid containing LiCl in a powder to liquid ratio of 2.0:1 to 5.0:1, in amounts effective to provide no more than 0.8 cm 3  of paste.