T 2130/11 02-12-2014

I. The appeal of the patent proprietor (appellant) lies against the decision of the opposition division announced at the oral proceedings on 16 June 2011 to revoke European patent 1 502 569. The patent was granted on the basis of 32 claims, claim 1 reading as follows:

"1. A method for providing a dental composition comprising providing a paste/paste two-part self-adhering dental composition comprising

(a) at least one acidic compound containing at least one acidic moiety selected from the group consisting of

FORMULA/TABLE/GRAPHIC

where R is an alkyl or aryl group;

(b) at least one polymerizable monomer without any acidic group where the polymerizable group is selected from the group consisting of an acrylate, a methacrylate and a vinyl group;

(c) at least one finely divided filler;

(d) at least one reducing agent: and

(e) at least one oxidizing agent:

wherein the ratio of the first paste containing (a) to a second paste not containing (a) or containing a lower concentration of (a) is greater than 1:1 (by volume), with the proviso that the composition does not comprise (a), (b), (c), (d) a substituted thiourea selected from the group consisting of 1-(2-pyridyl)-2-thiourea and 1?(2-tetrahydrofurfuryl)-2-thiourea, and (e) a hydroperoxide compound with at least one hydroperoxide group attached to a tertiary carbon."

II. A notice of opposition was filed in which revocation of the patent in its entirety was requested on the grounds of lack of novelty and of inventive step, of insufficiency of disclosure and of extension of the subject-matter beyond the content of the application as filed (Article 100(a), (b) and (c) EPC).

The opposition was based inter alia on the following documents:

D1: EP-A-1 479 364

D3: WO-A-03/086328

III. The decision was based on a set of claims filed as main request with letter dated 17 May 2011 and on three further sets of claims filed as first to third auxiliary requests during oral proceedings on 16 June 2011.

Claim 1 of the main request corresponded to claim 1 as granted with the addition of a process step ("wherein (d) at least one reducing agent and (e) at least one oxidizing agent form a self-cure initiator system in which when (d) at least one reducing agent and (e) at least one oxidizing agent come into contact with each other a redox reaction takes place and initiates polymerisation, leading to curing or hardening of the composition"), of a limitation on the ratio of the first paste to the second paste ("from 1.05:1 (by volume) to about 20:1 (by volume)") and of a second disclaimer worded as follows:

"and with the further proviso that, with reference to Tables 1, 2, and 3 of WO 03/086328, the composition does not comprise,

a first paste (Paste A1) consisting of;6.9 wt % Water, 24.2 wt % HEMA, 0.076 wt % BHT, 38.1 wt % AA:ITA:IEM, 3.5 wt % BisGMA, 2.5 wt % KPS, 24.2 wt % Zr-Si Filler, and 0.5 wt % Aerosil R812S,and a second paste (Paste B1) consisting of;13 wt % Water, 8.7 wt % HEMA, 1.4 wt % ATU, 0.16 wt % TBDMA, 37.2 wt % FAS I, 37.2 wt % FAS II, 0.5 wt % TiO2, and 1.2 wt % Aerosil R812S,

or a first paste (Paste A2) consisting of;

6.8 wt % Water, 1.2 wt % KS, 23.9 wt % HEMA, 0.075 wt % BHT, 37.6 wt % AA:ITA:IEM, 3.4 wt % BisGMA, 2.1 wt % KPS, 23.9 wt % Zr-Si Filler, and 1.0 wt % Aerosil R812S,

and a second paste (Paste B1) consisting of;

13 wt % Water, 8.7 wt % HEMA, 1.4 wt % ATU, 0.16 wt % TBDMA, 37.2 wt % FAS I, 37.2 wt % FAS II, 0.5 wt % TiO2, and 1.2 wt % Aerosil R812S,

or a first paste (Paste A3) consisting of;

11.5 wt % Water, 18.9 wt % HEMA, 0.079 wt % BHT, 42 wt % AA:ITA:IEM, 3.6 wt % BisGMA, 2.4 wt % KPS, 21 wt % Zr-Si Filler, and 0.5 wt % Aerosil R812S,

and a second paste (Paste B2) consisting of;

11.4 wt % Water, 10.3 wt % HEMA, 1.4 wt % ATU, 0.16 wt % TBDMA, 37.6 wt % FAS I, 37.6 wt % FAS II, 0.5 wt % TiO2, and 1.1 wt % Aerosil R812S,

or a first paste (Paste A4) consisting of;

11.5 wt % Water, 1.1 wt % KS, 18.7 wt % HEMA, 0.078 wt % BHT, 41.5 wt % AA:ITA:IEM, 3.6 wt % BisGMA, 2.4 wt % KPS, 20.8 wt % Zr-Si Filler, and 0.5 wt % Aerosil R812S,

and a second paste (Paste B2) consisting of;

11.4 wt % Water, 10.3 wt % HEMA, 1.4 wt % ATU, 0.16 wt % TBDMA, 37.6 wt % FAS I, 37.6 wt % FAS II, 0.5 wt % TiO2, and 1.1 wt % Aerosil R812S,

or a first paste (Paste A5) consisting of;

11.2 wt % Water, 2.6 wt % KDHP, 0.8 wt % KS, 18.3 wt % HEMA, 0.076 wt % BHT, 40.6 wt % AA:ITA:IEM, 3.5 wt % BisGMA, 2.3 wt % KPS, 20.3 wt % Zr-Si Filler, and 0.5 wt % Aerosil R812S,

and a second paste (Paste B2) consisting of;

11.4 wt % Water, 10.3 wt % HEMA, 1.4 wt % ATU, 0.16 wt % TBDMA, 37.6 wt % FAS I, 37.6 wt % FAS II, 0.5 wt % TiO2, and 1.1 wt % Aerosil R812S,

the Water being deionised water,

HEMA being 2-Hydroxyethyl methacrylate containing 150 ppm 4-methoxyphenol as an inhibitor,

BHT being 2,6-Di-tert-butyl-4-methylphenol,

AA:ITA:IEM being a polymer made by reacting AA:ITA copolymer with sufficient 2-isocyanatoethyl methacrylate to convert 16 mole percent of the acid groups of the copolymer to pendent methacrylate groups, according to the dry polymer preparation of Example 11 of U.S. Pat. No. 5,130,347, AA:ITA being a copolymer made from a 4:1 mole ratio of acrylic acid:itaconic acid, prepared according to Example 3 of U.S. Pat. No. 5,130,347,

BisGMA being 2,2-Bis[4-(2-hydroxy-3-methacryloyloxy-propoxy)phenyl]propane,

KPS being potassium persulphate,

Zr-Si Filler being a silane-treated zirconia-silica (Zr-Si) filler prepared as described in U.S. Pat. No. 4,503,169,

Aerosil R812S being a fumed silica,

KS being potassium sulphate,

KDHP being potassium dihydrogen phosphate,

ATU being Allylthiourea,

TBDMA being 4-tert-Butyl dimethylaniline,

FAS I being a fluoroaluminiunsilicate [sic] glass powder having a surface area of 2.8 m**(2)/g that has been silane-treated with a liquid treatment solution, the treatment solution being prepared by combining 4 parts A174 g-methacryloxypropyl trimethoxysilane and 60 parts water, adding glacial acetic acid to a pH of 3.01,and stirring for 0.5 hours, in which the treatment solution is mixed with 100 parts of the glass powder and an additional 67 parts of water to provide a slurry, the pH of the slurry is adjusted to 7.0 by adding 5% ammonium hydroxide and stirred for 30 minutes, dried for 24 hours at 95°C, crushed, and sifted through a 74- micrometer sieve, and

FAS II being a fluoroaluminiunsilicate glass powder having a surface area of 84 m**(2)/g that has been silane-treated with a liquid treatment solution, the treatment solution being prepared by combining 8 parts A174 g-methacryloxypropyl trimethoxysilane and 60 parts water, adding glacial acetic acid to a pH of 3.01,and stirring for 0.5 hours, in which the treatment solution is mixed with 100 parts of the glass powder and an additional 67 parts of water to provide a slurry, the pH of the slurry is adjusted to 7.0 by adding 5% ammonium hydroxide and stirred for 30 minutes, dried for 24 hours at 95°C, crushed, and sifted through a 74- micrometer sieve".

Claim 1 of the first auxiliary request included among other amendments a rewording of the second disclaimer in which the references to some patent documents and the definitions of some of the components of the disclaimed compositions by reference to their method of production were deleted. In claim 1 of the second and third auxiliary requests both disclaimers were deleted and the reducing agent and the oxidising agent were defined as being selected from specific lists.

IV. The decision under appeal can be summarised as follows:

a) Claim 1 of the main request did not meet the requirements of Article 123(2) EPC in view of the disclaimer over document D1, as it excluded more than necessary to restore novelty over D1 and did not have a basis in the original application in view of the combination of individual members from two lists of compounds. The other amendments complied with the requirements of Article 123(2) EPC. This was the case, in particular, for the addition of a process step related to a self-cure initiator system, as the missing wording from the corresponding passage of the description concerned two features, namely a mixing of the two pastes and the generation of free radicals, which were implicit for the skilled person. In addition claim 1 did not meet the requirements of Article 84 EPC in view of the disclaimer over document D3, which was neither clear, nor concise.

b) The amendments of claim 1 of the first auxiliary request were not a fair attempt to overcome the objection relating to Article 84 EPC, so that the requirements of Rule 80 EPC were not met.

c) Claim 1 of the second auxiliary request, which did not contain any of the two disclaimers, was allowable under Article 123(2) EPC, but did not meet the requirements of Article 123(3) EPC, as embodiments excluded in the granted claims by virtue of the disclaimer were now covered by the claim in view of the open wording "comprising".

d) The same objection under Article 123(3) EPC applied to claim 1 of the third auxiliary request, as the wording "dental composition comprising" did not exclude further ingredients to be present.

V. The appellant lodged an appeal against that decision. With the statement setting out the grounds of appeal dated 2 December 2011, the appellant filed 18 sets of claims as main request and first to seventeenth auxiliary requests. An amended version of the fourteenth and the seventeenth auxiliary requests was filed with letter of 18 February 2014.

Claim 1 of the main request corresponded to claim 1 of the main request on which the decision was based.

Claim 1 according to the first and second auxiliary requests corresponded to claim 1 of the main request, with the reformulation of first disclaimer as "with the proviso that the composition does not comprise (a), (b), (c), (d) a substituted thiourea, and (e) a hydroperoxide compound with at least one hydroperoxide group attached to a tertiary carbon" and "with the proviso that the composition does not comprise a hydroperoxide compound with at least one hydroperoxide group attached to a tertiary carbon" respectively.

In claim 1 of the third auxiliary request both disclaimers were deleted with respect to claim 1 of the main request and replaced by a single one which read "with the proviso that the composition does not comprise a substituted thiourea". Claim 14 of the third auxiliary request was identical to granted claim 14 and read as follows:

"14. The method of any preceding claim wherein the reducing agent is selected from the group consisting of aromatic sulfinate salt, aliphatic sulfinate salt, thiourea, ascobic [sic] acid, ascorbic acid derivative and salt, Fe(II) salt, Cu(I) salt, Co(II) salt, barbituric acid, barbituric acid derivative and salt, thiobarbituric acid, thiobarbituric acid derivative and salt, and combinations thereof."

VI. In the reply to the statement of grounds the opponents (respondents) raised inter alia several issues under Articles 84 and 123(2) and (3) EPC against the claims of the requests on file.

VII. In a communication sent in preparation of oral proceedings the Board addressed the objections of the respondents and with regard to the feature related to the self-cure initiator system expressed the preliminary opinion that "the omission of the mixing step and of the generation of free radicals appear to result in an extension of subject-matter with respect to the application as filed" (point 4.1 in the communication).

VIII. With letter of 31 October 2014 the appellant filed a further set of claims as eighteenth auxiliary request, whose claim 1 differed from claim 1 of the main request in that the feature related to the self-cure initiator system had been reworded as "wherein (d) at least one reducing agent and (e) at least one oxidizing agent form a self-cure initiator system in which, when the two pastes are mixed, (d) at least one reducing agent and (e) at least one oxidizing agent come into contact with each other and a redox reaction takes place which generates free radicals and initiates polymerisation of monomers, leading to curing or hardening of the composition" (amendments with respect to the main request are in bold) and anticipated the intention to introduce the same amendments in each of the requests on file.

IX. Oral proceedings were held on 2 December 2014. During the oral proceedings, two objections under Article 84 EPC were raised for the first time by the respondents during the discussion on the third auxiliary request, namely a lack of clarity related to the use of the word "about" in claim 1 and a contradiction related to the presence of thiobarbituric acid and its derivatives in claim 14. After deliberation on the main request and on the first to third auxiliary requests, the appellant filed an amended third auxiliary request, whose claims 1 and 14 read as follows (amendments with respect to the third auxiliary request are in bold, deletions in strike-through):

"1. A method for providing a dental composition comprising providing a paste/paste two-part self-adhering dental composition comprising

(a) at least one acidic compound containing at least one acidic moiety selected from the group consisting of

FORMULA/TABLE/GRAPHIC

where R is an alkyl or aryl group;

(b) at least one polymerizable monomer without any acidic group where the polymerizable group is selected from the group consisting of an acrylate, a methacrylate and a vinyl group;

(c) at least one finely divided filler;

(d) at least one reducing agent: and

(e) at least one oxidizing agent:

wherein (d) at least one reducing agent and (e) at least one oxidizing agent form a self-cure initiator system in which, when the two pastes are mixed, (d) at least one reducing agent and (e) at least one oxidizing agent come into contact with each other and a redox reaction takes place which generates free radicals and initiates polymerisation of monomers, leading to curing or hardening of the composition,

wherein the ratio of the first paste containing (a) to a second paste not containing (a) or containing a lower concentration of (a) ranges from 1.05:1 (by volume) to [deleted: about] 20:1 (by volume),

with the proviso that the composition does not comprise a substituted thiourea."

"14. The method of any preceding claim wherein the reducing agent is selected from the group consisting of aromatic sulfinate salt, aliphatic sulfinate salt, thiourea, ascobic [sic] acid, ascorbic acid derivative and salt, Fe(II) salt, Cu(I) salt, Co(II) salt, barbituric acid, barbituric acid derivative and salt, [deleted: thiobarbituric acid, thiobarbituric acid derivative and salt], and combinations thereof."

X. The arguments of the appellant, as far as relevant to the present decision, can be summarised as follows:

Main request, first and second auxiliary requests - clarity and conciseness

a) A disclaimer over document D3 was legitimate, D3 being prior art under Article 54(3) EPC. The only way to fulfil the provision set out in G 1/03 (OJ EPO 2004, 413) that a disclaimer may not remove more subject-matter than required to restore novelty was to disclaim the five relevant examples of D3 by using the exact terms of such examples. If the subject-matter of such examples was sufficiently clear to be anticipatory, then also a disclaimer repeating it had to be clear. Conciseness was also not an issue, as concise does not mean short, but no longer than needed. It was not fair to make the allowability of a disclaimer dependent on the disclosure of the prior art. As to the specific wording of the disclaimer, the references to patent documents were so precise that the skilled person was not required to search in the documents and product-by-process features were allowable as it was the case for a positive definition of a product.

Third auxiliary request - amendments and clarity

b) The disclaimer excluded an embodiment specifically disclosed in the application as filed and was as such a disclosed disclaimer. A basis was present both for the whole class of reducing agents in generic terms and for the specific compounds which were excluded, so that the insertion of the disclaimer did not result in singling out a not disclosed group of compounds. The conditions in G 2/10 (OJ EPO 2012, 376) for allowing a disclosed disclaimer were therefore met. Whether there were problems of sufficiency for the remaining subject-matter, was not relevant for Article 123(2) EPC. As to the feature related to the self-cure initiator system, the words of the original disclosure which were not present in claim 1 were superfluous, as it was evident to the skilled person that the two pastes were necessarily mixed when applying the dental composition and only free radical polymerisation could take place. Any different polymerisation, such as ionic polymerisation, would be inappropriate for a dental composition in view of the necessary presence of unpleasant catalysts.

c) There was no contradiction between claim 14 and claim 1; while some overlap may be present between the compounds listed in claim 14 and those disclaimed in claim 1, the overlapping compounds were clearly excluded by the disclaimer. The use of the word "about" in claim 1 did not make the wording of the claim unclear.

Amended third auxiliary request - admittance, clarity and amendments

d) The claims of the amended third auxiliary request addressed the two clarity issues raised for the first time at the oral proceedings before the Board and the objection under Article 123(2) EPC which had been raised in the communication of the Board. As to the latter objection, this point had been decided in favour of the appellant in first instance proceedings and the introduced amendment had already been proposed in the eighteenth auxiliary request with the indication that it applied to all requests on file. On that basis the request was a legitimate reaction to a new situation and should be admitted.

e) It was clear from the wording of the feature related to the self-cure initiator system that the cured or hardened composition was the composition resulting from mixing the two pastes. The lack of the word "mixed" did not therefore make the claim unclear, nor did it result in extension of subject-matter beyond the content of the application as filed. As to the other objections, the same reasons applied as detailed for the third auxiliary request.

Remittal

f) A remittal to the first instance was appropriate for consideration of novelty and inventive step.

XI. The arguments of the respondents, as far as relevant to the present decision, can be summarised as follows:

Admissibility of the appeal

a) Admissibility of the appeal was contested in view of the filing of a huge number of requests without clearly pointing out why any of these requests fulfilled the requirements of the EPC while requesting that the case be remitted to the first instance for consideration of novelty and inventive step. This behaviour was considered as a misuse of appeal proceedings and not complying with the Rules of Procedure of the Boards of Appeal.

Main request, first and second auxiliary requests - clarity and conciseness

b) The second disclaimer referred to several patent documents and extended over 67 lines. As summarised by the opposition division, this put an unreasonable burden on the public to find out what was protected and was not, therefore resulting in lack of clarity and of conciseness. The condition that a disclaimer may not remove more than required to restore novelty was not relevant when it came to the analysis of clarity and conciseness and the use of the exact wording of the prior art could not make the claim clear by definition.

Third auxiliary request - amendments and clarity

c) While a basis was available in the application as filed for the positive feature that the reducing agent was a substituted thiourea, there was no basis for the corresponding negative feature and what remained after the exclusion was a subgroup which was not directly and unambiguously derivable from the application as filed. The condition in G 2/10 (supra) on the subject-matter remaining after the introduction of the disclaimer was therefore not met. Moreover, the disclaimer excluded the preferred embodiment and the skilled person had no indication that the invention could work for the remaining subject-matter. The feature related to the self-cure initiator system had no basis in the application as filed, as two elements of the disclosure in the original description, namely the mixing of the two pastes to bring the reducing agent and the oxidising agent into contact and the generation of free radicals by the redox reaction, were not included in the claim. The missing elements could not be considered as implicitly covered by the claim, as "mix" and "come into contact" had clearly different meanings and polymerisation reactions other than free radical polymerisation were possible. As a further point, the definition of a first paste containing (a) and a second paste not containing (a) or containing a lower concentration of (a) did not correspond to the wording in the original application which referred to a first paste containing the acidic compound(s) or higher concentration of acidic compound(s). For all these reasons, the requirements of Article 123(2) EPC were not met.

d) There was a contradiction between the definition of the reducing agent in claim 14 which listed thiobarbituric acid, its derivatives and its salts and the disclaimer in claim 1 which excluded substituted thiourea, as thiobarbituric acid belongs to the excluded class. The use of the term "about" in claim 1 made the definition of the range of the volume ratio of the first paste to the second paste unclear.

Amended third auxiliary request - admittance, clarity and amendments

e) The amended third auxiliary request had to be rejected as late filed. It was relevant in this respect that the appellant had filed only the eighteenth auxiliary request with the reply to the communication of the Board and no other request including the amendment of the self-cure initiator system. The reformulated feature relating to the self-cure initiator system was still not in compliance with Articles 84 and 123(2) EPC in view of the absence of the term "mixed" with reference to the cured or hardened composition. All other objections under Article 123(2) EPC raised for the third auxiliary request still applied.

Remittal

f) A remittal to the first instance was not appropriate. In the present case there was a risk that claim 1 of the amended third auxiliary request was not novel and that further amended version of the claim did not comply with the requirements of Article 123(2) EPC, so that the case could be in a few years again before the Board with no progression. In any case, if the Board decided to remit, reference should be made in the decision to the passages of G 2/10 (supra) relevant for the analysis of novelty and inventive step in the case of a disclosed disclaimer (paragraphs 4.5.5 and 4.6 of the grounds).

XII. The appellant requested that the decision under appeal be set aside and the patent be remitted to the opposition division on the basis of the main request or, in the alternative, on the basis of one of the first to third auxiliary requests, the amended third auxiliary request and the fourth to eighteenth auxiliary requests, the main request and the first to thirteenth, fifteenth and sixteenth auxiliary requests having been filed by letter of 2 December 2011, the fourteenth and seventeenth auxiliary requests having been filed by letter of 18 February 2014, the eighteenth auxiliary request having been filed by letter of 31 October 2014 and the amended third auxiliary request having been filed during the oral proceedings on 2 December 2014.

XIII. The respondents requested that the appeal be rejected as inadmissible, or alternatively be dismissed.