DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The reply filed on January 23, 2026 has been entered into the prosecution for the application. Currently, claims 1-3, 5-9, and 11-20 are pending. Claims 4 and 10 have been cancelled. Claims 16-18 are withdrawn. Claims 1, 6, 15, and 16 have been amended. Claims 19 and 20 are new.
In view of the amendments to claim 15, the previous rejection of that claim under 35 U.S.C. 112(b) is withdrawn as moot.
All prior art grounds of rejection are withdrawn.
Applicant’s amendments necessitated the new ground(s) of rejection.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim(s) 1-3, 5-9, 11-15, and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pat. Pub. 2018/0244564 to Ritzberger et al. (hereinafter “Ritzberger”).
Regarding claim 1, Ritzberger teaches a lithium silicate glass ceramic (Abstract) which comprises from 0 to 3.0 wt.-% tin, calculated as SnO2 (¶ 0029). Ritzberger further teaches wherein the lithium silicate glass ceramic comprises 0 to 9.0 wt.-% P2O5 (¶ 0037; claim 4). These ranges substantially overlap the claimed ranges. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05). Ritzberger teaches wherein lithium disilicate is the main crystal phase (¶ 0041).
Regarding claim 2, Ritzberger teaches the lithium silicate glass ceramic comprising 68.0 to 79.0 wt.-% SiO2 (¶ 0015), a range which lies inside the claimed range.
Regarding claim 3, Ritzberger teaches the lithium silicate glass ceramic preferably comprising 10.0 to 13.5 wt.-% Li2O (¶ 0016), a range which substantially lies inside the claimed range of 10.0 to 21.0 wt.-% Li2O.
Regarding claim 5, Ritzberger teaches the lithium silicate glass ceramic comprising 2.0 to 7.0 wt.-% oxide of monovalent elements MeI2O selected from the group of K2O, Na2O, Rb2O, Cs2O and mixtures thereof (¶ 0018), a range which substantially lies inside the claimed range.
Regarding claim 6, Ritzberger teaches the lithium silicate glass ceramic comprising 0 to 5.0 wt.-% K2O (¶ 0020), a range which substantially lies inside the claimed range.
Regarding claim 7, Ritzberger teaches the lithium silicate glass ceramic comprising preferably 3.0 to 7.0 wt.-% oxide of divalent elements MeIIO selected from the group of CaO, MgO, SrO, ZnO and mixtures thereof (¶ 0021), a range which substantially overlaps the claimed range. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 8, Ritzberger teaches the lithium silicate glass ceramic comprising 0 to 8.0 wt.-% oxide of trivalent elements MeIII 2O3 selected from the group of Al2O3, B2O3, Y2O3, La2O3, Ga2O3, In2O3 and mixtures thereof (¶ 0025).
Regarding claim 9, Ritzberger teaches the lithium silicate glass ceramic comprising 1.0 to 6.0 and preferably 2.0 to 5.0 wt.-% Al2O3 (¶ 0027).
Regarding claim 11, Ritzberger teaches wherein the lithium silicate glass ceramic comprises lithium metasilicate (¶ 0041). Ritzberger further teaches that the lithium silicate glass ceramic preferably includes 30 to 55 wt.-% lithium disilicate crystals (¶ 0043) and preferably includes 0.5 to 25 wt.-% low quartz crystals (¶ 0044). Guided by these teachings and working within the constraints of the taught preferred ranges, one of ordinary skill in the art would have found it obvious to prepare a lithium silicate glass ceramic according to the present invention in which the glass ceramic comprises 1.0 to 50.0 wt.-% lithium metasilicate crystals. For example, a glass ceramic that included 45 wt.-% lithium disilicate crystals, 30 wt.-% lithium metasilicate crystals, and 25 wt.-% low quartz crystals would be consistent with the teachings of preferred ranges outlined above and would have lithium metasilicate as main crystal phase; such a glass ceramic would read on every limitation of claim 11. Thus, a glass ceramic which comprises 1.0 to 50.0 wt.-% lithium metasilicate crystals would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention.
Regarding claim 12, Ritzberger teaches wherein the lithium silicate glass ceramic preferably comprises 30 to 55 wt.-% lithium disilicate crystals (¶ 0043), a range which overlaps the claimed range of 50.0 to 90.0 wt.-%. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 13, Ritzberger teaches a starting glass (see ¶ 0052) which comprises the components of the glass ceramic according to claim 1 (see above, p. 3).
Regarding claim 14, Ritzberger teaches the starting glass which comprises nuclei for the crystallization of lithium disilicate (see ¶¶ 0052, 0055).
Regarding claim 15, Ritzberger teaches a glass ceramic which comprises the components of the glass ceramic according to claim 1 (see above, p. 3) and wherein the glass ceramic is in the form of a powder, a granulate, a blank or a dental restoration (¶ 0071; claim 17).
Regarding claims 19 and 20, Ritzberger teaches the glass ceramic comprising 0 to 3.0 wt.-% tin, calculated as SnO2 (¶ 0038); this taught range substantially overlaps the recited ranges in both claim 19 and claim 20. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Claim(s) 1-3, 5-9, 13-15, and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over CA 2,252,660 A1 to Schweiger et al. (hereinafter “Schweiger”).
Regarding claim 1, Schweiger teaches a lithium silicate glass ceramic (Abstract) comprising 0.01 to 3.0 wt.-% tin, calculated as SnO2 (p. 6, line 17), and 0 to 8.0 wt.-% P2O5 (p. 5, line 28); thus, in the case of both SnO2 and P2O5, Schweiger teaches a wt.-% range that overlaps the claimed range. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05). Lithium disilicate is the only crystal phase mentioned for the glass ceramic disclosed by Schweiger (see p. 1, line 2; claim 1; Abstract), and therefore one of ordinary skill in the art reasonably would conclude that lithium disilicate is the main crystal phase of the taught lithium silicate glass ceramic.
Regarding claim 2, Schweiger teaches the lithium silicate glass ceramic comprising 57.0 to 75.0 wt.-% SiO2 (p. 5, line 20), a range which substantially overlaps the claimed range. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 3, Schweiger teaches the lithium silicate glass ceramic comprising 13.0 to 19.0 wt.-% Li2O (p. 5, line 27), a range which substantially overlaps the claimed range. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claims 5 and 6, Schweiger teaches the lithium silicate glass ceramic comprising 0.5 to 7.0 wt.-% K2O (p. 5, line 26), a range which falls within the recited range of claim 5 and substantially overlaps the recited range of claim 6. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 7, Schweiger teaches the lithium silicate glass ceramic comprising 0.1 to 5.0 wt.-% MgO and 0 to 6.0 wt.-% ZnO (p. 5, lines 23-24); in combination, these ranges fall within the claimed range of 0 to 15.0 wt.-% recited in claim 7. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 8, Schweiger teaches the lithium silicate glass ceramic comprising 0 to 2.5 wt.-% Al2O3 and 0.1 to 4.0 wt.-% La2O3 (p. 5, lines 21-22); in combination, these ranges fall within the claimed range of 0 to 15.0 wt.-% recited in claim 8. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 9, Schweiger teaches Schweiger teaches the lithium silicate glass ceramic comprising 0 to 2.5 wt.-% Al2O3 (p. 5, line 21), a range which substantially overlaps the claimed range. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 13, Schweiger teaches a starting glass of the glass ceramic (see p. 4, lines 25-25; p. 7, lines 11-12; claim 1).
Regarding claim 14, Schweiger teaches wherein the starting glass comprises nuclei for crystallization of lithium disilicate (p. 8, lines 8-14, teaching that it is possible to produce a glass—including a starting glass—with nuclei; lithium disilicate is the only crystal phase mentioned, see claim 1; Abstract).
Regarding claim 15, Schweiger teaches the glass ceramic in the form of a blank (p. 7, lines 32-34) or a dental restoration (p. 8, lines 21-22).
Regarding claim 19, Schweiger teaches lithium silicate glass ceramic (Abstract) comprising 0.01 to 3.0 wt.-% tin, calculated as SnO2 (p. 6, line 17), a range which substantially overlaps the claimed range. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Regarding claim 20, Schweiger teaches lithium silicate glass ceramic (Abstract) comprising 0.01 to 3.0 wt.-% tin, calculated as SnO2 (p. 6, line 17), a range which substantially overlaps the claimed range. In a case where claimed ranges “overlap or lie inside ranges disclosed by the prior art,” a prima facie case of obviousness exists (see MPEP 2144.05).
Response to Arguments
Applicant’s arguments filed January 23, 2026 have been fully considered but they are not persuasive. On page 5 of the Remarks submitted with the reply filed January 23, 2026 (hereinafter “Remarks”), Applicant points out that Ritzberger recites that the glass ceramic “preferably” comprises 2.0 to 6.0 wt.-% P2O5 (see Ritzberger at ¶ 0017) and that all of the disclosed example embodiments in Ritzberger that include lithium disilicate as the main crystal phase include at least 3.3 wt.-% P2O5 (see Ritzberger at Table 1). However, a prior art reference is prior art for all that it teaches (MPEP 2121.01), and “[d]isclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments” (MPEP 2123). Thus, Ritzberger still teaches the full range of 0 to 9.0 wt.-% P2O5, overlapping the range recited in claim 1 as amended; even if Ritzberger’s preferred range and disclosed examples fall outside the claimed range, one of ordinary skill in the art, guided by Ritzberger’s teachings, would have found it obvious to select a content of P2O5 from any point within the full taught range. Applicant argues that “a skilled person would understand that in order for P2O5 to act as nucleating agent, it should be present in an amount of at least 2.0 et.-%. Moreover, in the absence of P2O5 as nucleating agent, the glass ceramics of Ritzberger cannot be expected to form lithium disilicate as main crystal phase” (Remarks at pp. 5-6). These conclusions go beyond the explicit teachings of Ritzberger and do not necessarily follow from the Ritzberger data. In the first place, P2O5 is not the only possible nucleating agent (see, e.g., Ritzberger at ¶ 0040, indicating that ZrO2, for example, can serve as a nucleating agent). Secondly, Ritzberger does not explicitly teach that 2.0 wt.-% P2O5 is the lower limit for P2O5 being effective for inducing nucleation; that is speculation and argument by Applicant. Arguments presented by Applicant cannot take the place of factually supported objective evidence (MPEP 2145).
Conclusion
Applicant’s amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/P.A.F./Examiner, Art Unit 1731
/JENNIFER A SMITH/Primary Patent Examiner, Art Unit 1731