PATENTS ACT 1952

DECISION OF A DELEGATE OF THE COMMISSIONER OF PATENTS

Re:		Application No. 548207 by DENTSPLY INTERNATIONAL INC., and opposition by BAYER AKTIENGESELLSCHAFT under section 59.

Background

The Office published acceptance of application 548207 in the Official Journal on 28 November 1985.  In a decision dated 5 June 1986, the delegate of the Commissioner allowed Bayer Aktiengesellschaft (Bayer) an extension of time to lodge a notice of opposition.  The opponent lodged notice of opposition under section 59 on 28 April 1986.   

All evidence stages were completed by 28 December 1989. 

The opposition was set down for hearing in Sydney on 9 October 1990.  Dr A Bennett of Counsel, and Mr J O'Connor, patent attorney, and Ms J Newton of Spruson and Ferguson represented Dentsply International Inc (Dentsply).  Mr J Siely, patent attorney, of Arthur S Cave & Co represented Bayer.

The notice of opposition listed grounds (c) to (i) of sub-section 59(1).  At the hearing Mr Siely relied on grounds of prior claiming, prior publication, novelty and non-compliance with section 40.

Subject matter

Dentsply lodged application 548207 under the Patent Cooperation Treaty.  The date of filing was 26 August 1981.  The application claims earliest priority based on US application number 181417 and US application number 293143 of 26 August 1980 and 17 August 1981 respectively.  

The subject matter of the invention relates to the control of dusting in dry powdered dental impression materials.  These materials when mixed with water form an impression paste capable of setting to a solid.

The specification as accepted describes, at page 2, the problem of prior art dental impression materials in the following terms:

	"Prior to mixing the powdered and liquid components, it is common practice for the user to shake the container  in which the various powdered components of the impression material are stored to fluff them.  This fluffing is done to facilitate the measuring or proportioning of the powdered components, using a scoop or ladle which is provided with the container.  Under such circumstances, however, when the top of the container is opened, some of the powder tends to dusting, i.e. becoming airborne and floating out of the container.  Dusting also tends to occur when the powdered components are mixed with water or a water substitute due, at least in part, to the difficulty with which the powdered components are wet by the water.  In practice, the powdered components are placed in a flexible mixing bowl and water is added to it.  The powdered components do not wet immediately and the bulk of the powder floats for a period of time on the surface of the water during mixing, thus permitting some dusting to occur.  The dusting problem is further exaggerated because the harder one stirs the powdered components/water mix the greater is the opportunity for a portion of the powder to become airborne.

	This dusting, which occurs primarily when a portion of the filler in the powdered component separates from the remaining powdered components and becomes airborne upon mixing or shaking, or upon stirring with the liquid component of the impression material has become the cause of concern because of its potential health hazard.  (Woody, R.D. et al., JADA 94, 501. 1977)".

At page 4, the specification goes on to provide a solution to this problem:

	"In accordance with the present invention, the greater ease and speed with which the powdered components are wet by water during mixing, the elimination of airborne particles of powder, and other objects of the invention are achieved when the constituent powdered particles or at least a portion thereof are coated with a minor amount of agent or compound which is readily and rapidly wet, dispersed or dissolved by water or substitute liquid component of the impression material.  This coating of the powdered particles causes the individual particles to be attracted to one another so that they do not easily become airborne, and permits the powdered particles to be easily wet by the water or substitute liquid."

There are 10 accepted claims, including 3 independent claims (claims 1, 2 and 4) and an omnibus claim.  Claims 1, 2 and 4 are as follows:

	"1.	A method for controlling the dusting of a powdered impression material comprising coating at least a portion of the powder with an agent which when dry renders the material in its dry powdered form to have reduced dusting characteristics compared to the same material absent the agent, said agent coated powder portion being readily and rapidly wet, dispersed or dissolved by water to form from the powdered impression material a settable impression paste.

	2.	A method of increasing the speed with which a powdered impression material becomes wet with water upon admixture therewith and for reducing the tendency of the impression material toward dusting, comprising coating the powder or part of it with an agent which is readily and rapidly wet, dispersed or dissolved upon mixing with water to form a paste.

	4.	A dry powdered impression material composition adapted upon mixing with water to form an impression paste capable of setting to a solid, comprising an alginic acid salt component and a filler component, wherein particles of said powdered composition or at least a portion thereof have a coating of coating agent which is readily and rapidly wet, dispersed or dissolved by the water when the impression material composition is mixed for forming the settable paste, said dry powdered impression material composition having reduced dusting characteristics as compared to the same composition absent the coating agent."

Proposed amendments

At the hearing Mr Siely argued that claims 1 and 2 did not comply with section 40.  He said the claims were too wide and should be limited to alginate materials.  Also, he said, they overlapped the prior art presented as evidence in support, particularly exhibits 5 to 13, as claims 1 and 2 were not limited to dental impression materials.

Mr O'Connor, after Mr Siely's arguments and during the hearing, lodged a request under section 77 to amend claims 1 and 2 by limiting the claims to "a powdered alginate or alginate substitute dental impression material".  I asked him whether there was any reason for not treating claim 4 in the same manner.  That is, limiting it to dental impression materials.  In response, Mr O'Connor proposed to amend the claim by inserting "dental" after "powdered" at line 1 of the claim.

As the proposed amendments appear to overcome certain defects under section 40, I will, from this point, consider the specification as proposed to be amended.

Evidence and submissions

Evidence in support was served, by the opponent on 17 August 1987.  This consisted of:

a.	a statutory declaration by Dr Peter Schwabe, dated 6 May 1987, and 13 exhibits; 

	Dr Schwabe, of Leverkusen (Germany), states that:

	.	he is employed by, and is authorised to make the declaration on behalf of, Bayer;

	.	he has qualifications corresponding to a PhD in organo metallic chemistry; and 

	.	he has been employed by Bayer since 1966 and since 1975 in the biomedical and dental field as a research chemist and group leader with responsibility for the development of impression materials suitable for all impression techniques in dental surgery.

b.	a statutory declaration, dated 5 August 1987, by James Siely, patent attorney, and 4 exhibits.  

Evidence in answer, consisting of a statutory declaration, dated 14 September 1988, by Donald Raynor and 1 exhibit was served by the applicant on 17 September 1988.  

	Mr Raynor, of Belgrave Victoria, declares that:

	.	he has been employed by Dentsply and previously, Amalgamated Dental Company Ltd U.K., a company that is now owned by Dentsply, for 35 years.  He has had 13 years experience in the research laboratories of Amalgamated Dental Co and is co-inventor of UK patent number 923,078;

	.	He holds a national certificate in chemistry from South Western Polytechnic in London and a Diploma of the Plastics Institute from Borough Polytechnic in London.

Evidence in reply, consisting of a statutory declaration by Dr Peter Schwabe and 5 exhibits was served by the opponent on 28 December 1989.

Dr Schwabe, in his statutory declaration (evidence in support), deposes as follows:

	"10.	At page 2a final paragraph the specification states that (other) "objects and advantages are achieved when the constituent powdered particles, or at least a portion thereof, are coated with a minor amount of an agent...".  ...I am unclear as to the amount of agent that is employed and how such amount is determined.  The expression "minor amount" is never used again in the text.  Page 3 lines 23-24 discloses an amount of "1-10% by weight based on the total weight of the powdered components" but qualifies this disclosure with the word "usually".  In the various compositions of Example 4 no amount is specified.

	11.	Page 2a-3 states that the "agent or compound" (the coating agent) is "readily and rapidly wet ... by ... water or substitute liquid component of the impression material"."  The expression "substitute liquid component" is also used elsewhere in the text.  However it is never discussed in greater detail or defined.

	12.	It is not clear to me that the specification fully describes the manner in which the coating agent is applied. .... In Example 1 it is stated that the diatomaceous earth filler "was wet with the polypropylene glycol coating agent".  Polypropylene glycols, unless of high molecular weight, are of course liquid - so the reader may conjecture that the diatomaceous earth filler was simply admixed with the liquid to achieve the desired coating.  The reader, however, cannot even conjecture in respect to Example 4.  This Example makes use of several coating agents, the first of which xanthan gum, is a solid.  How this solid substance, and any other solids included in the list page 3, carry out the function attributed to them has not been described.

	14a.	...the specification at page 2 lines 23-26 indicates that the powdered material is a material that includes a "filler. A filler component is not necessarily present in the material of claims 1 and 2 (compare claim 4).

	14b.	The coating is applied to "at least a portion of the powder" (claim 1) or to "the powder or a part of it" (claim 2).  ...how this is carried out is not always clearly described.  The only clear description is in respect of the application of liquid polypropylene glycol to the filler component of the powdered components.

	14c.	There is confusion as to the properties of the "coating agent".  According to the description at page 2a final paragraph the agent is "readily and rapidly wet, dispersed or dissolved by the water...".  Similar language occurs at page 3.  Whilst claim 2 appears to be in substantial agreement with these statements, claim 1 is clearly not in agreement.  In claim 1 is the "agent coated powdered portion" (not the agent itself) which is "readily and rapidly wet...to form...a suitable impression paste".

	14d.	...The only characterisation of the coating agent in claim 1 is the statement that it "when dry renders the material... to have reduced dusting characteristics...the agent".  Firstly, apart from corresponding wording at page 2 there are no passages in the description which explicitly state what the agent will do "when dry".  But further, and of more importance, is the fact that claim 1 would appear to include within its ambit a coating agent which, whilst not readily and rapidly wet..." in itself, can confer these characteristics upon the coated powder.  Such a coating agent is clearly not disclosed in, nor envisaged by, the specification.

	14e.	In claim 2 the amount of coating agent is unspecified.  The claim is broad enough to include within its ambit methods in which the increase in speed and the tendency for dusting to be reduced are both negligible.  A similar criticism applies to claim 1 which in addition is so broad as to cover dust control only.

	15.	Claim 4... is deficient in that the amount of "coating agent" is unspecified.

	16.	...Insofar as claims 6 and 7 specify agents the application of which has not been clearly described, the claims are themselves deficient.

	17.	...It is known to coat powdered particulate materials, as used both in dental and other applications so as to reduce the dusting of materials.  It is known to apply such a coating by means of agents of the type employed in the Dentsply specification - which agents, of their very nature, also serve to increase the wettability of the materials being coated.  

		...such an "invention" is lacking in novelty, and is also obvious, in the light of what is known in the art in Australia on the relevant date of the Dentsply application.

In paragraphs 18-28 of his declaration Dr Schwabe amplifies his comments on the lack of novelty of the invention by reference to UK 1,073, 772 (exhibit 3), DE 25 11 168 (exhibit 4), US 2,844,486 (exhibit 5), US 2,727,827 (exhibit 6), US 32,900,611 (exhibit 7), US 4,136,050 (exhibit 8), CA 979,314 (exhibit 9), US 3,846,240 (exhibit 10), UK 2,053,174 (exhibit 11), UK 1,383,444 (exhibit 12) and UK 1,583,213 (exhibit 13).  These citations all describe aspects of the coating of powdered materials to reduce dusting and increase wettability using coating agents of the type described in the Dentsply specification.

	29.	...the words "when dry" which appear in claim 1.  These words do not appear in the specification (either the description or claims) as filed.  Claim 1 was introduced in September 1985 during the examination of the Dentsply application ....  At the same time page 2a as filed was replaced by amended page 2 and 2a....  If a critical characteristic of the coating agent is now said to be that it carries out its reduced dusting function when dry, two conclusions surely follow. Firstly the characteristic has no basis in the specification as filed.  Secondly any claim which omits the characteristic is presumably inadequate."

The second statutory declaration lodged as evidence in support is by Mr J Siely and provides evidence of the dates of publication of exhibits 3 to 13 and copies of Au 282,721 (equivalent to UK 1,073,772) and CA 979,314.

Section 40

I am faced with a description of the invention, that is, the control of dusting and wettability in dental impression materials, presented in some instances in very broad terms.

Mr Siely mentioned a number of matters referred to in Dr Schwabe's declaration, which he argued, meant the specification failed to comply with section 40.  These concerned the fair basis and clarity of claims 1 and 2 and the sufficiency and clarity of the description.

In summary, the major points of Mr Siely's submission are that:

a.	the meaning of the term "minor amount" (Schwabe para 10) was unclear.  Claims 1, 2 and 4 should specify the amount of "coating agent" (Schwabe paras 14e and 15);

Dr Bennett argued the amount of coating agent is not critical and the term "minor amount" has a well accepted meaning, that is, an amount below 50% of the composition.  

I accept this.  The claims do not need to refer to a "minor amount" of the coating agent.

b.	the expression "substitute liquid component" (Schwabe para 11) is not defined or discussed in any detail;

It is true, as Mr Siely argued, that the term "substitute liquid component" is unclear and examples of substitute liquids have not been disclosed.  The description at page 2a lines 19 to 26, however, states that "In accordance with the present invention ... constituent powdered particles, or at least a portion thereof, are coated with a minor amount of an agent or compound which is readily and rapidly wet, dispersed or dissolved by the water or substitute liquid component ...".  Claims 1, 2 and 4 refer only to water and are clear in this respect.

In my view, the description should be amended to either provide appropriate examples of "substitute liquid components" or to remove references to these materials.

c.	the manner in which the coating agent is applied is not sufficiently described (Schwabe para 12, 14b);

The specification describes a method of applying the coating agent to the powdered impression materials.  In the case of the liquid agents, the process involves mixing components together with the agent.

Dr Schwabe suggests it would be difficult to coat the powdered impression materials with solid xanthan gum.

In the case of a solid material, for example xanthan gum, Mr Raynor, in para 10 of his statutory declaration (evidence in answer), states that:

	"all substances described in example 4 that are normally in the solid state have been previously characterised sufficiently for workers in the field to readily select solvents capable of dissolving the substances.  Thus, in my opinion, persons manufacturing impression materials would be able to select appropriate solvents for such solid coating agents and then apply the liquid solution as described in Example 1".  

Xanthan gums have for some time been known to be readily soluble in water to give highly viscous solutions at low concentrations (see The Merck Index - 9th Edition (1976) p 1297).  

I agree with Mr Raynor's statements and can find no difficulty with the manner in which such solid materials are applied as coating agents.

Mr Siely also argued that the method of claims 1 and 2 is not clear as methods must have a means of "doing" as well as an "object".  I presume by this that Mr Siely contends that the claim should include detail of the process steps involved in applying the coating to the powdered impression material.  

Mr Raynor states (declaration para 13) that:

	"techniques for applying coating agents to particles are well known ... manufacturers of impression materials would have no trouble in understanding this".  

I accept this.  The invention is for the reduction of dusting and increasing the wettability of the powdered impression material and not for a method of coating these materials.  It is not necessary, in my view, for the claims to specify well known coating steps.

d.	claims 1 and 2 should include reference to a "filler material" (Schwabe para 14a);

Mr Siely argued, on the basis of statements on page 2 of the specification, that the claims should include the filler material.  Dr Bennett said that claims 1 and 2 are for methods for improving a known product.  Mr Raynor also said, in his declaration, that the claims relate to a method for controlling dusting and wettability rather than to the impression material per se.  

In my view the "filler material" is not required to be an essential feature of the method.  Claims 1 and 2 do not therefore need to refer to the filler material.

f.	the properties of the "coating agent " are not clear;

	- in claim 1 it is not clear whether the "agent" itself or "the agent coated portion" is "readily and rapidly wet...to form a suitable impression paste" (Schwabe para 14c);

	- there is no support for claiming the use of coating agents other than hydrophilic coating agents (Schwabe para 14d);

	- the words "when dry" were not in the specification as lodged, hence there is no support for the characteristic of the coating agent that it carries out its reduced dusting function when dry (Schwabe para 29);

Dr Bennett argued lines 22-26 on page 2a when read in the context of the whole description make it clear that the relevant words should be read to include the phrase underlined as follows:

	"Other objects and advantages are achieved when the constituent powdered particles, or at least a portion thereof, are coated with a minor amount of an agent or compound, the result of which is readily or rapidly wet, dispersed or dissolved by the water or substitute liquid compound."

It is clear, Dr Bennett said, that what is readily and rapidly wet, dispersed or dissolved is the agent coated powder portion as claimed in claim 1 and that this "clarification is clear upon a reading of page 3 lines 1 to 4" of the specification.

Dr Bennett referred to the rules for construction of claims provided by Sheppard JJ in Decor Corporation Pty Ltd v Dart Industries Inc (1988) 13 IPR 385 as an authority.  

I can not agree that the phrase "the result of" should be read into the paragraph on page 2a as Dr Bennett suggests.

It appears to me, from a reading of the whole specification, including an analysis of the examples of the coating agent given on page 3 lines 6 to 20 (all of which, including block copolymers of polysiloxanes and polyethylene glycols, appear to be themselves wettable), that both the coating agent and the coated powdered impression material are readily and rapidly wet, dispersed or dissolved by the water or substitute liquid component.  The specification only discloses coating agents possessing this property.

I find that claim 1 is unclear and not fairly based.  It should be amended to clearly state that both the coating agent itself and the coated powdered impression material are readily and rapidly wet, dispersed or dissolved upon mixing with water.

The specification discloses on page 3 lines 1 to 4 "This coating of the powdered impression materials causes the individual particles to be attracted to one another so that they do not easily become airborne, and permits the powder particles to be easily wet...".  It seems to me coating " with an agent which when dry renders the material in its dry powdered form to have reduced dusting characteristics compared to the same material absent the agent" is disclosed in the specification as originally lodged.  

In my view the words "when dry" are not objectionable.  

g.	claims 6 and 7 are deficient in that they specify agents the application of which has not been described (Schwabe para 16).

Mr Raynor replies to paragraph 16 of Dr Schwabe's declaration as follows:

	"the preferred method of application is set forth with respect to the polypropylene glycol agent.  Manufacturers of impression agents would readily understand how to apply the coating agents.  Thus I believe that further exemplification is unnecessary."

I accept this and agree that further exemplification is unnecessary.

I have found another instance of non-compliance with section 40.

According to the description, coating agents can be applied "in varying dust reducing, powder wetting enhancing amounts" (page 3 lines 22-23) ... to provide a composition wherein dusting is significantly reduced and the powdered components are significantly more rapidly wet upon mixing as compared to the composition absent the coating agent (page 3 lines 28 to 30). 

In my view, claims 1, 2 and 4 and the corresponding description should refer to using "sufficient coating agent to provide a coated powdered impression composition which has a significant reduction in dusting and is significantly more rapidly wet, compared to the composition absent the coating agent".  The meaning of the phrases "significant reduction in dusting" and "significantly more rapidly wet, dispersed or dissolved by water" should be clearly defined.

Anticipation

Mr Siely argued that Claims 1 and 2, as proposed to be amended, are anticipated by exhibits 3 and 4 of the evidence in support, that is GB 1073772 and DE 2511168.  Exhibits 5 to 13 are only relevant where the claims include impression materials other than dental impression materials.  None of these exhibits refer to dental impression materials and in the light of the amendments proposed at the hearing, they no longer appear to be relevant.

Mr Siely argued that although the preferred embodiment of GB 1,073,772 provides the impression materials in sachets, the description covers other ways of coating the dental impression materials to prevent dusting.  He submitted claims 1 and 2 of application No. 548207 are therefore not novel and prior published by the GB specification.  He directed my attention to the statements on pages 1 and 2 of the GB specification which read as follows:

	"We have found that dental impression material of the kind referred to may be improved by the incorporation of a water soluble film-forming organic polymer ... whilst the film-forming polymer can be incorporated in the remainder of the dental impression material in powdered form it is much preferred to provide it in the form of an individual envelope containing ingredients of the dental impression material."

He cited Griffin v Issacs (1942) AOJP 739 as an authority to support his argument.

Dr Bennett cited General Tyre and Rubber Company v Firestone Tyre and Rubber Company Limited (1972) RPC 457 and argued there are no clear signposts in GB 1,073,772 leading to the method claimed in claims 1 and 2 of the Dentsply application.  The signposts, she said, lead away from the claimed method.

This citation discloses an improved impression material which is both flexible enough to avoid breaking plaster teeth and strong enough to avoid being damaged when the plaster teeth are removed.  The film-forming polymer is not suggested as a means to overcome the dusting problem rather its purpose appears to be to improve the flexibility and elasticity of the impression material.

The citation on page 2 column 2 states that:

	"It is an object of the invention to provide a dental impression material giving a gel of improved flexibility and elasticity, so that the composition is less critical than heretobefore.  Another object is to provide an improved presentation of the dental impression material."

This is followed immediately by the paragraph quoted above.

Now to DE 25 11 168, in particular the certified translation of exhibit 4.  Mr Siely argued this anticipates claims 1 and 2 of the present application in that it relates to dental impression material within the scope of the present claims.

This citation relates to an impression gel with improved accuracy of formation, a finer surface and improved compatibility with gypsum.  It does not relate to reducing dusting or improving wettability and would not lead to the method of the present application.

I find that neither claim 1 nor 2 of the present application are prior published by or not novel in the light of either GB 1073772 or DE 2511168.  

I find nothing to support the contention that the Dentsply invention is obvious.

Mr Siely also argued that section 159A is appropriate to accepted claim 1.  He said amendments lodged on 24 September 1985 include accepted claim 1 which is broader in scope than original claim 1 and hence claims new matter.  Thus according to section 159A, the priority date of the claim should be treated as the date the new matter was disclosed in a statement of proposed amendments, that is 24 September 1985.  Claim 1, he argued, is therefore prior claimed by Bayer AU patent application No. 586169.

I have found earlier that claim 1 as proposed to be amended is unclear and not fairly based.  Claim 1 was broadened by the September 1985 amendment.  The amendment resulted in an accepted claim 1 with broad (and unclear) terminology.  In my opinion it did not result in the claiming of any new matter.  Section 159A is therefore not appropriate as the claim does not claim new matter.  In any case I will consider whether claim 1 is prior claimed by application 586119.

The Bayer specification discloses as coating agent, on page 1a, "certain hydrophobic liquids" (sic) in their powdered form, in particular paraffin.  There is no disclosure, except as prior art, of the coating materials used in the Dentsply application.

Claims 1 to 7 of the accepted Bayer specification are for an impression material per se containing a paraffin coating agent.  Claims 8 to 10 are process claims and claims 11 and 12 are omnibus claims.

Claims 8 to 10 are as follows:

	"8.  Process for the preparation of a moulding material according to claims 1 to 7, characterised in that paraffin is added, with stirring, to the mixture of the components in the form of a powder, or to a portion thereof.

	9.  Process according to claim 8, characterised in that the paraffin treatment is carried out at 50-100oC.

	10. Process according to claims 8 or 9, characterised in that the addition is carried out in a suitable mixer."

Claim 1 of the present application is the only claim in contention.  The claim, as proposed to be amended, is as follows:

	"1.  A method for controlling the dusting of a powdered alginate or alginate substitute dental impression material comprising coating at least a portion of the powder with an agent which when dry renders the material in its dry powder form to have reduced dusting characteristics compared to the same material absent the agent, said agent coated powder portion being readily and rapidly wet, dispersed or dissolved by water to form from the powdered impression material a settable impression paste."

Claims 2 to 10 of application 548207 are clearly not prior claimed by the claims of application number 586169 by Bayer.

Using the principle applied in Travers Corporation's Application (1964) RPC 26, that is, that a distinct claim has to be found "as a matter of substance, not necessarily of words" in the earlier specification, I find that claim 1 of the Dentsply application is not prior claimed by claims 8 to 10 of the Bayer application.

Conclusion

I have found that the opposition succeeds because the specification does not comply with the requirements of section 40 since the claims lack fair basis and are unclear.  I consider these deficiencies can be readily overcome by amendment action.  Amendments have already been proposed under section 77.  I afford the applicant 60 days from the date of this decision to seek further amendment of the specification.

I award costs against the applicant.

Bob Sawyer
Supervising Examiner of Patents

Patent Attorneys for the applicant: Spruson & Ferguson, Sydney
Patent Attorneys for the opponent : Arthur S Cave and Co Sydney