US5730598A — Prosthetic implants coated with hydroxylapatite a…

Claim 1

Independent Claim 58 words

A method for producing an implant having a coating of at least about 90% by weight of crystalline hydroxylapatite, comprising the steps of: plasma spraying said implant with hydroxylapatite; placing said implant in a sealable, pressurizable vessel; heating said implant in the presence of steam while in said vessel; cooling said implant; and rinsing said implant with water.

Claim 2

Independent Claim 58 words

A method for producing an implant having a coating of at least about 90% by weight of crystalline hydroxylapatite, comprising the steps of: plasma spraying said implant with hydroxylapatite; placing said implant in a sealable, pressurizable vessel; heating said implant in the presence of steam while in said vessel; cooling said implant; and rinsing said implant with water.

Claim 3

Dependent Claim 26 words

The method of claim 1 further comprising the step of removing carbon dioxide (CO 2 ) from said steam before said step of heating said implant.

Claim 4

Dependent Claim 34 words

The method of claim 1 in which said heating step includes heating said implant to at least about 250 degrees Celsius at a final pressure of at least about 270 pounds per square inch.

Claim 5

Dependent Claim 32 words

The method of claim 1 further comprising the steps of: rinsing said implant in acetone to remove water after said rinsing step; and drying said implant in air to remove said acetone.

Claim 6

Independent Claim 86 words

A method for treating a dental implant, comprising the steps of: plasma spraying said implant with a coating of hydroxylapatite, wherein said coating includes a crystalline phase of hydroxylapatite, amorphous calcium phosphate, calcium oxide, tri-calcium phosphates (including α-TCP and β-TCP), and tetracalcium phosphate; heating said implant while in a pressurized environment in the presence of water; converting said amorphous calcium phosphate to crystalline hydroxylapatite; converting said calcium oxide to calcium hydroxide; exposing said implant to an aqueous environment; and dissolving said calcium hydroxide from said coating.

Claim 7

Independent Claim 86 words

A method for treating a dental implant, comprising the steps of: plasma spraying said implant with a coating of hydroxylapatite, wherein said coating includes a crystalline phase of hydroxylapatite, amorphous calcium phosphate, calcium oxide, tri-calcium phosphates (including α-TCP and β-TCP), and tetracalcium phosphate; heating said implant while in a pressurized environment in the presence of water; converting said amorphous calcium phosphate to crystalline hydroxylapatite; converting said calcium oxide to calcium hydroxide; exposing said implant to an aqueous environment; and dissolving said calcium hydroxide from said coating.

Claim 8

Dependent Claim 26 words

The method of claim 5 further comprising the step of removing carbon dioxide (CO 2 ) from said water before said step of heating said implant.

Claim 9

Dependent Claim 59 words

The method of claim 5 in which said heating step includes heating said implant to a final temperature of between about 250 to 300 degrees Celsius at a final pressure of between about 800 to 1100 pounds per square inch, wherein said implant is maintained at said final temperature and said final pressure for about 0 to 20 minutes.

Claim 10

Dependent Claim 29 words

The method of claim 5 further comprising the steps of: converting said tri-calcium phosphates (including α-TCP and β-TCP) to crystalline hydroxylapatite; and converting said tetracalcium phosphate to crystalline hydroxylapatite.

Claim 11

Dependent Claim 23 words

The method of claim 5 in which said exposing step includes submersing said implant in water for between about one to two hours.

Claim 12

Dependent Claim 29 words

The method of claim 5 in which said heating step includes heating said implant until said coating has at most about 5% by weight of said amorphous calcium phosphate.

Claim 13

Dependent Claim 28 words

The method of claim 5 in which said heating step includes heating said implant until said coating has at most about 1% by weight of said calcium hydroxide.

Claim 14

Dependent Claim 135 words

A process for purifying a coating on an implant, comprising the steps of: plasma spraying said implant with hydroxylapatite to produce a first coating including both crystalline hydroxylapatite and non-crystalline hydroxylapatite; hydrothermally treating said first coating at a temperature above 200 degrees Celsius but below a temperature of about 300 degrees Celsius to convert said first coating into a second coating, wherein a portion of said non-crystalline hydroxylapatite of said first coating converts to crystalline hydroxylapatite to produce said second coating having a greater percent by weight of crystalline hydroxylapatite than said first coating; and leaching said second coating to convert said second coating into a final coating, wherein calcium hydroxide in said second coating is dissolved to produce said final coating having a greater percent by weight of crystalline hydroxylapatite than said second coating.

Claim 15

Dependent Claim 135 words

A process for purifying a coating on an implant, comprising the steps of: plasma spraying said implant with hydroxylapatite to produce a first coating including both crystalline hydroxylapatite and non-crystalline hydroxylapatite; hydrothermally treating said first coating at a temperature above 200 degrees Celsius but below a temperature of about 300 degrees Celsius to convert said first coating into a second coating, wherein a portion of said non-crystalline hydroxylapatite of said first coating converts to crystalline hydroxylapatite to produce said second coating having a greater percent by weight of crystalline hydroxylapatite than said first coating; and leaching said second coating to convert said second coating into a final coating, wherein calcium hydroxide in said second coating is dissolved to produce said final coating having a greater percent by weight of crystalline hydroxylapatite than said second coating.

Claim 16

Dependent Claim 26 words

The process of claim 12 in which said steps of hydrothermally treating and leaching produce said final coating having about 97% by weight of crystalline hydroxylapatite.

Claim 17

Dependent Claim 44 words

The process of claim 12 in which: said step of hydrothermally treating further comprises the step of: heating said implant in a pressurized water-vapor environment, and cooling said implant; and said step of leaching further comprises the step of submersing said implant in water.

Claim 18

Dependent Claim 44 words

The process of claim 12 in which: said first portion of said non-crystalline hydroxylapatite includes tri-calcium phosphates (including α-TCP and β-TCP), tetra-calcium phosphate, and amorphous calcium phosphate; and said second portion of said non-crystalline hydroxylapatite includes tri-calcium phosphates, tetra-calcium phosphate, and amorphous calcium hydroxide.

Claim 19

Dependent Claim 105 words

A process for treating an implant for implantation in bone to achieve osseointegration, said process comprising the steps of: providing an implant; plasma-spraying hydroxylapatite on said implant to form a first preliminary coating on said implant; heating said implant and said first preliminary coating in a water-vapor atmosphere to convert said first preliminary coating to a second preliminary coating comprising at least about 90% by weight of crystalline hydroxylapatite; and exposing said implant and said second preliminary coating to liquid water to convert said second preliminary coating to a final coating comprising a greater percentage by weight of crystalline hydroxylapatite than said second preliminary coating.

Claim 20

Dependent Claim 105 words

A process for treating an implant for implantation in bone to achieve osseointegration, said process comprising the steps of: providing an implant; plasma-spraying hydroxylapatite on said implant to form a first preliminary coating on said implant; heating said implant and said first preliminary coating in a water-vapor atmosphere to convert said first preliminary coating to a second preliminary coating comprising at least about 90% by weight of crystalline hydroxylapatite; and exposing said implant and said second preliminary coating to liquid water to convert said second preliminary coating to a final coating comprising a greater percentage by weight of crystalline hydroxylapatite than said second preliminary coating.

Claim 21

Dependent Claim 21 words

The process of claim 16 in which said final coating comprises between about 90% to 98% by weight of crystalline hydroxylapatite.

Claim 22

Dependent Claim 30 words

A dental implant, comprising: a substrate; and a surface coating on said substrate, wherein said coating comprises plasma-sprayed hydroxylapatite having at least about 95 percent by weight of crystalline hydroxylapatite.

Claim 23

Dependent Claim 30 words

A dental implant, comprising: a substrate; and a surface coating on said substrate, wherein said coating comprises plasma-sprayed hydroxylapatite having at least about 95 percent by weight of crystalline hydroxylapatite.

Claim 24

Dependent Claim 19 words

The dental implant of claim 18 in which said coating is essentially free of calcium oxide and calcium hydroxide.

Claim 25

Dependent Claim 95 words

The dental implant of claim 18 in which said surface coating is prepared by: plasma-spraying hydroxylapatite on said substrate to form a first preliminary coating on said substrate; heating said substrate and said first preliminary coating in a water-vapor atmosphere to convert said first preliminary coating to a second preliminary coating comprising at least about 90% by weight of crystalline hydroxylapatite; and exposing said substrate and said second preliminary coating to liquid water to convert said second preliminary coating to a final coating that is essentially free of calcium oxide, calcium hydroxide, and calcium carbonate.

Claim 26

Dependent Claim 64 words

An implant for implantation in bone to achieve osseointegration, comprising: a substrate; and a surface coating on said substrate comprising plasma-sprayed hydroxylapatite, wherein said surface coating, as determined by X-ray diffraction analysis over a range of 20 from about 16° to about 40°, includes at least about 90 percent by weight of crystalline hydroxylapatite and is essentially free of calcium oxide and calcium hydroxide.

Claim 27

Dependent Claim 64 words

An implant for implantation in bone to achieve osseointegration, comprising: a substrate; and a surface coating on said substrate comprising plasma-sprayed hydroxylapatite, wherein said surface coating, as determined by X-ray diffraction analysis over a range of 20 from about 16° to about 40°, includes at least about 90 percent by weight of crystalline hydroxylapatite and is essentially free of calcium oxide and calcium hydroxide.

Claim 28

Dependent Claim 26 words

The implant of claim 21 in which said coating is treated with a two stage process including a hydrothermal treatment stage and then a leaching stage.

Claim 29

Dependent Claim 59 words

The implant of claim 21 in which said coating comprises about 97% by weight of crystalline hydroxylapatite after said substrate is heated in a water-vapor atmosphere to a final temperature of about 300° Celsius and a final pressure of about 1100 pounds per square inch and held at said final temperature and said final pressure for about 15 minutes.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-03-23	2001-09-22	2002-03-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-03-23	2005-09-22	2006-03-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-03-23	2009-09-22	2010-03-24	$7700.00	Window Closed / Lapsed

Prosthetic implants coated with hydroxylapatite and process for treating prosthetic implants plasma-sprayed with hydroxylapatite

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