US 6729876

I'll search for authoritative information on this specific patent number.

US Patent 6,729,876 — Analyst Summary

Verification note: Patent number checked literally as 6,729,876. The USPTO/Google Patents record and the PTAB exhibit copy of the granted patent (USOO6729876B2) both match. No results for adjacent numbers were substituted.

Sources consulted: Google Patents (https://patents.google.com/patent/[US6729876](/patent/US6729876)/en), FreePatentsOnline (https://www.freepatentsonline.com/6729876.html), Patexia (https://patexia.com/us/patent/06729876), the PTAB exhibit copy of the patent (IPR2025-00816, Ex. 1005), CourtListener opinion for Align Technology, Inc. v. ITC, 771 F.3d 1317 (Fed. Cir. 2014), and the Align investor-relations litigation disclosures.

1. Bibliographic data

Abstract (verbatim): "Systems and methods are disclosed to prepare a malocclusion treatment plan by selecting a tooth treatment pattern from a library of predetermined tooth treatment patterns; and generating the malocclusion treatment plan implementing the selected tooth treatment pattern."

2. Plain-language overview of the independent claims

The claims are directed to computer-assisted automated staging of orthodontic treatment: rather than a clinician manually sequencing tooth movement, the software picks a predefined movement pattern from a stored library and derives tooth paths and stages from it. Based on the granted claim set, the independent claims are claim 1, the "producing data sets" method claim (appearing as claim 21), the computer-readable-medium claim (claim 24), the automated-staging method claim (28), and the two system claims (30 and 31). Claim numbering for the intermediate independent claims is inferred from the published claim ordering; the claim text below is what the sources show.

• Claim 1 (computer-implemented method — the flagship claim): Select a tooth treatment pattern from a library of predetermined tooth treatment patterns; generate the malocclusion treatment plan implementing the selected pattern; and generate a series of successive tooth arrangements progressing from a first to a second tooth arrangement. (FreePatentsOnline renders the third step as "generating a series of successive tooth arrangements…")

• Claim 21 (method, data-set variant): Same selection and generation steps, but the output is data representing a series of successive tooth arrangements from a first to a second arrangement (i.e., the digital data set rather than the plan per se).

• Claim 24 (computer-readable medium): Code to select one tooth treatment pattern from the library; code to generate the malocclusion treatment plan in accordance with the selected pattern; and code to generate the series of successive tooth arrangements. (Claims 25–26 add fabrication-machine control: successive positive models and/or a negative appliance, e.g., laser-scanning a non-hardened polymeric resin.)

• Claim 28 (method — automated staging tied to manufacture): Select one teeth treatment pattern from a plurality of predetermined patterns; generate a treatment plan in accordance with the selected move pattern by (a) generating a tooth path for each tooth and (b) determining a series of treatment stages; then control a fabrication machine to produce successive appliances for the tooth arrangements.

• Claim 30 (computer system): A processor, a display coupled to the processor, and a data storage device containing code to select a tooth treatment pattern from the library and code to generate the malocclusion treatment plan implementing the selected pattern.

• Claim 31 (computer system, means-plus-function): Means for selecting a tooth treatment pattern from the library and means for generating the malocclusion treatment plan implementing the selected pattern on a digital model of the patient's teeth.

Representative dependent-claim subject matter (material to the disclosure, though not independent): determining collision-free shortest tooth paths (claim 3); clinical prescriptions such as space closure, reproximation, dental expansion, flaring, proclination, distalization, and lower incisor extraction (claims 4–5); staging with per-stage movement limits (claims 6–7); appliance generation per stage (claim 8); and the described library of movement patterns — all-equal (X-type), A-shaped, V-shaped, M-shaped, W-shaped, symmetric/asymmetric staircase, and equal-equal (XX-type) — implemented by the recursive frame-subdivision, A-shape, PreEqual/equal, and V-shape routines of Figs. 14–20B.

Minor source discrepancy to flag: the granted claim 5 wording retrieved from FreePatentsOnline reads "…flaring, proclination, distalization…", while the Google Patents summary/definition text for the same sentence reads "…flaring, distalization…" without "proclination." Treat the granted-claim text (with "proclination") as controlling.

3. Litigation / proceedings

The patent is expired (June 21, 2019), so it cannot be asserted for ongoing infringement; its recent appearances are as prior art, not as an asserted patent.

• ITC Inv. No. 337-TA-562 (2006) — Certain Incremental Dental Positioning Adjustment Appliances, Align v. OrthoClear. US 6,729,876 was listed among the patents in the 2006 Consent Order (along with 6,685,469; 6,450,807; 6,394,801; 6,398,548; 6,722,880; 6,629,840; 6,699,037; 6,318,994; 6,602,070; 6,471,511; and 6,227,850).
• CAFC Nos. 2013-1240 and 2013-1363 — Align Technology, Inc. v. International Trade Commission, 771 F.3d 1317 (Fed. Cir. July 17, 2014). Enforcement of that Consent Order; the '876 patent appears in the appendix list of Consent Order patents. There is no CAFC 2026 docket for US 6,729,876 that I could find.
• Current (2025–2026) proceedings where '876 appears only as prior art: IPR2025-00815 and IPR2025-00816 (and a related petition family), filed April 12, 2025 by ClearCorrect Operating LLC against Align patents; US 6,729,876 is Petitioner's Exhibit 1005 ("Chishti-876"). Notably, Align has argued (and the Board has credited in a related IPR) that Chishti-876 teaches away from "round-tripping" — i.e., from moving a tooth further than absolutely necessary (see Ex. 1005, 14:46–51; also 17:1–7 on the A-type movement as evidence of a "schedule of movement").
• Concurrent Align district-court matter: Align Technology, Inc. v. ClearCorrect Operating, LLC, et al., No. 6:24-cv-00187-ADA-DTG (W.D. Tex.), with a motion hearing set for May 27, 2026 (§ 101 invalidity and preclusion motions). I found no indication that US 6,729,876 is an asserted patent in that case.
• Also unrelated to this number: Align's 2026 UPC/ITC and China actions against Angelalign concern "treatment planning," "bite ramp/power ridge," multilayer-material, and extraction-closure patents — not US 6,729,876.

4. Confidence and uncertainties

• High confidence: title, inventors, assignee, application number, filing date, priority date, issue date, abstract, expiration, terminal disclaimer/PTA, ITC 337-TA-562 listing, and the 2014 CAFC citation.
• Moderate confidence: exact claim numbering for the intermediate independent claims (21 and 24 are inferred from claim-dependency ordering in the published claim list, not read verbatim from the patent).
• Explicit uncertainties: (a) My final search for a dedicated IPR2025-00816 institution decision on US 6,729,876 returned no result before my search budget was exhausted, so I cannot confirm whether the Board instituted any IPR naming '876 as the challenged patent (as opposed to prior art). (b) The Google Patents "Definitions" transcript and the granted claim text differ slightly on claim 5's list of prescriptions; I flagged this rather than auto-correcting it. (c) The Google Patents full text as fetched is truncated mid-PAR discussion ("In additio…"); column/line cites for some passages therefore come from the PTAB exhibit copy rather than the fetched page.

I'll research litigation involving US patent 6729876. Let me search multiple sources.

Let me dig deeper into the specific litigation records for the '876 patent.

Let me verify the appellate proceedings and check for any other assertions of the '876 patent.

Litigation Involving U.S. Patent No. 6,729,876

Identification first (no auto-correction applied): The number as given, 6729876, corresponds to US 6,729,876 B2 — "Tooth path treatment plan," inventors Muhammad Chishti, Huafeng Wen, and Woncheol Choi, assignee Align Technology, Inc.; filed 2001‑08‑29; granted 2004‑05‑04; priority date 1999‑05‑13; expired 2019‑06‑21. In the briefs and orders below it is referred to as "the '876 patent." This is confirmed by the patent's own Google Patents record, which also carries a "Family has litigation" tag: https://patents.google.com/patent/US6729876/en

Bottom line: Every known assertion of the '876 patent that I could locate arose from the 2005–2007 Align Technology v. OrthoClear dispute (ITC + parallel district court actions), all of which were resolved by the October 2006 global settlement. I found no evidence that the '876 patent was asserted in any later Align campaign (e.g., the ClearCorrect matters, which asserted different patents).

1. ITC Investigation No. 337‑TA‑562 (the core proceeding on the '876 patent)

• Caption/Subject: Certain Incremental Dental Positioning Adjustment Appliances and Methods of Producing Same
• Complainant/Plaintiff: Align Technology, Inc. (Santa Clara/San Jose, CA)
• Respondents/Defendants: OrthoClear, Inc. (San Francisco, CA); OrthoClear Holdings, Inc. (Tortola, BVI); OrthoClear Pakistan Pvt., Ltd. (Lahore, Pakistan)
• Jurisdiction: U.S. International Trade Commission (Section 337, 19 U.S.C. §1337)
• Filing date: Complaint filed January 11, 2006; investigation instituted February 2006 (notice at 71 Fed. Reg. 7995, Feb. 15, 2006).
• '876 patent asserted: Claims 1–22 and 28 of U.S. Patent No. 6,729,876 (11 patents + trade‑secret misappropriation were asserted in total).
• Outcome: Terminated by consent order on November 13, 2006 (ALJ Order No. 32 granting the joint motion filed Oct. 13, 2006). The consent order bars importation/sale of the accused aligners and any infringing articles until expiration of the last to expire of the patents‑in‑suit, which expressly include the '876 patent.

Sources:

• ITC Notice of Investigation: https://www.usitc.gov/secretary/fed_reg_notices/337/337-ta-562.institution.1139514931_0.pdf
• 71 Fed. Reg. 7995 (Feb. 15, 2006): https://www.federalregister.gov/documents/full_text/xml/2006/02/15/E6-2164.xml
• Commission notice of termination / Consent Order: https://www.govinfo.gov/content/pkg/FR-2006-11-17/pdf/E6-19446.pdf and https://investor.aligntech.com/static-files/1656ec96-b2d1-4244-838c-af3ebae08db8

2. Parallel district court actions (OrthoClear)

The October 2006 settlement (Intellectual Property Transfer Agreement, effective Oct. 12, 2006) listed the following actions as settled by the parties; all were dismissed. The '876 patent was asserted only in the Wisconsin action:

Sources / evidence:

• Align 8‑K (Aug. 10, 2006) describing the Wisconsin action and listing 6,729,876 among the asserted patents: https://investor.aligntech.com/static-files/1c700b84-6ca7-495f-a112-3cc1de27de1d
• IP Transfer Agreement listing all five "Actions": https://aligntech.gcs-web.com/node/13486/html
• N.D. Cal. docket (3:05‑cv‑02948): https://www.courtlistener.com/docket/[5734805](/patent/5734805)/align-technology-inc-v-orthoclear-inc/ (see Docs. 336 and 342)

Settlement outcome (Oct. 2006): OrthoClear discontinued worldwide design/manufacture/sale of removable aligners, assigned its IP to Align, consented to the ITC exclusion/consent order, and all lawsuits were dismissed; Align made a one‑time $20 million payment to OrthoClear Holdings. (8‑K and IP Transfer Agreement, above.)

3. ITC enforcement proceeding under the '562 Consent Order (2012–2013)

• Complainant: Align Technology, Inc.
• Respondents: ClearCorrect Operating, LLC (Houston, TX); ClearCorrect Pakistan (Private), Ltd. (Lahore); and bound officers Mudassar Rathore, Waqas Wahab, Nadeem Arif, and Asim Waheed
• Jurisdiction: U.S. International Trade Commission (enforcement of the '562 consent order, 19 C.F.R. §210.75)
• Filing date: Complaint filed March 1, 2012 (corrected March 22, 2012); instituted April 25, 2012.
• '876 patent: Not asserted in the enforcement action — Align's enforcement complaint was based only on the '511 and '880 patents. The '876 patent remained one of the patents covered by the underlying consent order but was not itself litigated in the enforcement.
• Outcome: ALJ Order No. 57 found the accused digital datasets were "articles manufactured" within the consent order, but the Commission reversed (Jan. 23, 2013) and terminated with a finding of no violation, holding that the consent order did not expressly cover electronic transmissions. Align appealed.

Sources: 77 Fed. Reg. notice of institution https://www.govinfo.gov/content/pkg/FR-2012-05-01/pdf/2012-10366.pdf ; USITC Pub. 4555 (background of the '562 and '833 matters) https://www.usitc.gov/publications/337/pub4555.pdf

4. Federal Circuit appeals

The patent's Google Patents litigation record and USITC Pub. 4555 identify two Federal Circuit appeals arising from the '562 enforcement matter:

• Align Technology, Inc. v. ITC, Nos. 2013‑1240 and 2013‑1363 (Fed. Cir.)

The appeal addressed whether the ITC's Section 337 jurisdiction reaches the electronic transmission of digital data. A panel opinion issued July 17, 2014 (https://cafc.uscourts.gov/opinions-orders/13-1240.opinion.7-17-2014.1.pdf); the issue was ultimately decided en banc in ClearCorrect Operating, LLC v. ITC, 810 F.3d 1283 (Fed. Cir. 2016) (en banc), holding that the ITC's authority does not extend to electronic transmissions of digital data.

⚠️ Caveat: I was able to confirm the docket numbers and the panel opinion URL, and my training data indicates the en banc ClearCorrect decision is the reported outcome of this line of appeals, but I could not independently verify within the search results reviewed the exact per‑docket disposition of 2013‑1240 vs. 2013‑1363. Please confirm the final mandate directly via PACER/CM‑ECF before relying on it.

Summary table

What I did not find

• No assertion of the '876 patent in the later ClearCorrect ITC investigation 337‑TA‑833 — that investigation asserted U.S. Patent Nos. 6,217,325; 6,471,511; 6,705,863; 6,722,880; 7,134,874; and 8,070,487. (See the ALJ's Final ID excerpt: https://www.docketalarm.com/cases/[PTAB](/ptab)/IPR2016-00270/...)
• No district‑court or ITC case other than the OrthoClear matters above in which I could confirm the '876 patent was a patent‑in‑suit.
• No IPR/PGR identified against the '876 patent specifically (the IPR2016‑00270 at Docket Alarm is an inter partes review of the '037 patent, not the '876 patent).

If you need the authoritative docket‑level confirmation (especially the exact Federal Circuit disposition and any post‑2013 assertions), the next steps would be a PACER/CM‑ECF pull for the five case numbers above and the two Federal Circuit dockets, plus a Darts‑IP "family 23215135" litigation report (linked from the Google Patents page). I could not complete those pulls within the search steps available, so I have flagged those items rather than asserting them as confirmed.

I'll verify the PTAB landscape for this patent, both from the canonical structured block and via web search for anything the ODP may not have indexed.

Let me pin down what the 2025 ClearCorrect petitions actually challenge, and check for any reexamination or other AIA trial naming '876 as the challenged patent.

Proceedings overview

Zero (0) AIA trial proceedings — IPR, PGR, or CBM — have ever named US 6,729,876 as the challenged patent: the canonical PTAB proceedings block (USPTO ODP) is empty, and independent web searching of PTAB dockets, IPR2025 petition families, and Align/ClearCorrect trial papers surfaced no petition against '876. Breakdown by status: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. The defensive posture this creates is not "the patent has survived two IPRs and is hardened" and not "claims 1–5 have been canceled" — it is a third posture: the '876 patent is entirely untested at the Board, and it expired on 2019-06-21, so an IPR against it is a practical dead end; its real relevance today is as the prior-art reference ClearCorrect and Align are litigating around, not as a patent you can knock out.

No AIA trial proceeding on file — US 6,729,876

• Type: N/A (no Inter Partes Review, Post-Grant Review, or Covered Business Method review identified)
• Filed: N/A
• Status: "No AIA trial proceedings for this patent as of the most recent ingest" (verbatim from the structured PTAB proceedings block). No contrary proceeding was surfaced by web search.
• Judge panel: N/A
• Petition grounds: N/A
• Institution decision: N/A
• Final Written Decision: N/A — no claim of '876 has ever been construed, canceled, or confirmed by a PTAB panel.
• Settlement / termination: N/A
• Appeal: No PTAB-FWD appeal exists for '876. (The Federal Circuit activity on the Google Patents record — Nos. 2013-1240, 2013-1363 — is the ITC consent-order enforcement appeal, not a PTAB appeal; see the previously generated litigation section.)
• Defensive value: There is no § 315(e)(2) estoppel attaching to '876, because estoppel requires an instituted IPR. Any prior-art ground against '876 is therefore legally unblocked — but the patent is expired and cannot be asserted going forward, so an IPR on '876 buys a defendant nothing. Do not spend petition budget here.

Adjacent proceedings where '876 appears — context only, NOT challenges to '876

These are included because they are the only PTAB traffic involving the '876 patent, and they matter to strategy. In each, '876 is prior art (Petitioner's Exhibit 1005, "Chishti-876"), never the patent under review. Do not cite any of these as a validity ruling on '876.

IPR2025-00816 — ClearCorrect Operating, LLC v. Align Technology, Inc.

• Type: Inter Partes Review
• Filed: 2025-04-12
• Challenged patent: US 11,369,456 B2 ("the '456 patent") — not '876. '876 is Ex. 1005, the Chishti reference
• Status: Pending as of the last docket entry I could verify; Patent Owner's Brief in Support of Discretionary Denial filed 2025-07-08. ⚠️ I could not confirm an institution or denial decision for -00816 within this research window — flag rather than assume.
• Judge panel: not confirmed for this docket
• Petition grounds: § 103 obviousness over Chishti-'511 / Chishti-'876-based combinations, plus Becker, directed at claims including independent claims 1, 8, 11, and 13 of the '456 patent.
• Institution decision: not confirmed
• Defensive value for '876: This is where '876 does its work. Align's discretionary-denial brief argues that the Board, in an earlier IPR against a family member, "found that the same prior art Petitioner relies on now actually taught away from the modification Petitioner proposes in ground 2," and that "Chishti-876['s] … instruction to avoid 'round-tripping'" defeats the obviousness theory. That teaching-away finding is the single most useful statement in the record about '876 as a reference — it cuts against anyone trying to build a round-tripping/staggering invalidity case out of '876.

IPR2025-00815 — ClearCorrect Operating, LLC v. Align Technology, Inc.

• Type: Inter Partes Review
• Filed: 2025-04-12
• Challenged patent: US 10,524,879 B2 ("the '879 patent") — not '876. '876 cited as Ex. 1005
• Status: Institution denied (35 U.S.C. § 314) on 2025-10-23.
• Judge panel: Kevin F. Turner, Kristina M. Kalan, Cynthia M. Hardman (Hardman, A.P.J., writing)
• Petition grounds: § 103, claims 1–24 of the '879 patent, over Chishti-'876 / Chishti-'511-based movement-pattern combinations with Sachdeva and Becker.
• Institution decision: Denied 2025-10-23 — the panel found Petitioner did not establish a reasonable likelihood of prevailing on at least one challenged claim, after construing Chishti-'876's own text against the Petitioner: "the scheduling algorithm determines the treatment path while avoiding 'round-tripping,' i.e., while avoiding moving a tooth along a distance greater than absolutely necessary to straighten the teeth … [s]uch motion is highly undesirable, and has potential negative effects on the patient" (quoting Chishti-'876, 14:46–51). The Director had earlier declined to deny on discretionary grounds and referred the petition to the Board.
• Settlement / termination: N/A
• Appeal: none identified
• Defensive value: A ready-made, panel-authored rebuke of the exact "use Chishti-'876's movement patterns" theory. If an adversary hands you a § 103 chart built on '876 + round-tripping, quote the -00815 denial.

IPR2017-01829 — ClearCorrect Operating, LLC v. Align Technology, Inc.

• Type: Inter Partes Review
• Filed: 2017 (docket number index only)
• Challenged patent: US 8,038,444 B2 ("the '444 patent") — not '876
• Status: Institution denied ("The Board did not institute the '444 IPR")
• Petition grounds: § 103 over Snow, Hultgren/Kesling, and Lemchen; Chishti-'876 cited as prior art.
• Institution decision: Denied. The panel rejected the combination as to claims 1, 2, 9, and 10, and specifically rejected the Petitioner's use of Chishti-'876's general teachings to supply a "staggering" limitation — noting Chishti-'876 is "silent as to any consideration of purposefully 'delaying' the movement of a tooth."
• Defensive value: Second independent confirmation that panel practice treats '876 as teaching away from deliberate delayed/staggered movement, i.e., the opposite of what modern Align continuation claims recite.

IPR2025-00814 / -00817 / -00818 / -00819 / -00820 / -00821 — ClearCorrect Operating, LLC v. Align Technology, Inc.

• Type: Inter Partes Review (companion family, all filed April 2025)
• Challenged patents (per Align's mandatory notices, Paper 3, in IPR2025-00815): -00814 = US 10,456,217; -00817 = US 10,791,936; -00818 = US 10,973,613; -00819 = US 11,154,384; -00820 = US 11,648,090; -00821 = US 11,648,091. None is '876.
• Defensive value: Confirms the 2025 campaign is a coordinated multi-patent attack on Align's post-2004 continuation family, using '876 as the historical prior-art anchor. '876 is the ammunition, not the target.

IPR2016-00270 — ClearCorrect v. Align (context)

• Challenged patent: US 6,699,037 — not '876. Included only because it is often mistakenly conflated with an '876 proceeding.

Ex parte reexaminations (2015–2017) — flag, unverified for '876

• Align's brief states ClearCorrect filed 26 ex parte reexamination requests against Align patents between 2015 and 2017 (Reexam Control Nos. 90/013,581; 90/013,947; 90/013,457; 90/013,904; 90/013,905; 90/013,917; 90/013,6xx, and others). I could not verify whether any of these named US 6,729,876. Reexaminations are not AIA trials and create no § 315(e) estoppel, so they do not change the analysis — but if a defendant wants a complete post-issuance file history for '876, this docket family is the place to pull the file wrapper.

Strategic summary

Claim status of '876: everything is UNTESTED. Claims 1–31 are all unadjudicated — none canceled, none confirmed, none construed by any PTAB panel. There is no narrowing through AIA trial, no surviving-claims list, and no FWD to quote. The patent also carries a terminal disclaimer and expired 2019-06-21, so it is not an assertable patent going forward. If someone sends a demand letter citing 6729876, the correct response is not "its claims are dead at the PTAB" (they are not — they were never tested); it is "this patent expired in 2019, and it is cited by the industry as prior art against Align's later patents, not asserted by Align."

Estoppel landscape: clean slate, no barriers. Because no IPR was ever instituted against '876, no petitioner (and no privy) is estopped under § 315(e)(2) as to '876, and there is no § 325(e) issue. ClearCorrect's estoppel exposure runs to the '456, '879, '444, '217, '936, '613, '384, '090 and '091 patents from its own 2025 petitions and its 2017 petition — not to '876. Practically, a defendant has every prior-art ground available against '876. That is cold comfort, since an expired patent cannot be infringed.

Pattern signals. The same petitioner — ClearCorrect Operating, LLC (with ClearCorrect Holdings, Straumann USA, LLC, and Institut Straumann AG as identified RPIs) — has filed a large coordinated IPR family against Align in 2025 (-00814 through -00821), on top of a 2015–2017 reexamination campaign and earlier IPRs (-00270, -01829) against family members. There is no defensive aggregator (e.g., Unified Patents) in the chain for '876. The patent owner (Align) is litigating aggressively and defensively: it briefed discretionary denial in the 2025 IPRs and lost the discretionary fight in -00815 before losing on the merits. The recurring theme across every PTAB record involving '876 is Chishti-'876's own teaching away from "round-tripping" (avoid moving a tooth further than absolutely necessary) — a finding the Board credited and Align weaponized against ClearCorrect's obviousness theories.

Recommended next steps

• If you are a defendant being asserted against '876 specifically: verify the assertion date against the 2019-06-21 expiration and the terminal disclaimer. Any pre-suit or post-expiration demand premised on '876 is defective on its face; the patent cannot support ongoing infringement. There is no PTAB FWD to link for this patent because none exists — say that plainly rather than implying a validity ruling.
• If you are defending against Align's continuation patents (e.g., the '444, '217, '879, '456 family) where '876 is offered as prior art: use the two panel findings above — IPR2025-00815 institution denial, 2025-10-23 ("avoiding 'round-tripping' … potential negative effects on the patient," quoting Chishti-'876 14:46–51) and the IPR2017-01829 denial ("Chishti-'876 is silent as to any consideration of purposefully 'delaying' the movement of a tooth"). Both are directly available as Ex. 1008 in the 2025 dockets.
• If you need to know the fate of the 2025 petitions themselves: the -00815 denial is public; the dispositions of -00814, -00816, -00817, -00818, -00819, -00820, and -00821 were not confirmable in this research window. Pull them from USPTO PTAB E2E (https://e2e.uspto.gov) or the PTAB public-information API rather than relying on secondary dockets. Under the current 1-year statutory trial clock (§ 316(a)(11)), any instituted petition from April 2025 would have an FWD due on or about April 2026.
• Do not file an IPR against '876. Absence of PTAB activity here is not a signal that the patent is "hardened" — it is a signal that the patent is expired and low-value as a target. The industry's energy is spent using '876 as art, and that is where a defendant's forensic effort should go.
• Gap to close: whether any of the 26 ClearCorrect ex parte reexaminations (2015–2017) touched '876. I could not verify this; the file wrapper is the only reliable source. Flagging rather than asserting it either way.

(Cross-reference note: the earlier "PTAB proceedings on file" block and the litigation summary are consistent — the litigation sections correctly identify the '876 patent as an ITC/Court patent and the 2025 IPRs as ClearCorrect-as-prior-art-user. One earlier caveat, that the -00816 disposition was unconfirmed, still stands; -00815's denial is now confirmed at 2025-10-23.)

I'll research the assignment record for US 6,729,876 across the USPTO Assignment Center and cross-referenced sources.

Let me look for the specific assignment reel/frame for this patent and any post-issuance transfers.

Let me dig into the specific assignment records via assignment databases.

Assignment & Ownership Analysis — US 6,729,876

Identification (literal, no auto-correction): patent number 6729876 = US 6,729,876 B2, "Tooth path treatment plan," Chishti et al., application 09/943,097, filed 2001‑08‑29, issued 2004‑05‑04, priority 1999‑05‑13, assignee Align Technology, Inc.

Tool limitation (stated up front): The USPTO Assignment Search pages (assignmentcenter.uspto.gov and assignment.uspto.gov) are JavaScript‑driven and did not render to my search tools, and my search budget was exhausted before I could pull a raw reel/frame page for this specific patent. The assignment picture below is reconstructed from the Google Patents Legal‑Events record (which is populated from the same USPTO assignment data) plus corroborating Align/OrthoClear filings. Where a reel/frame or correspondent is not provable, I say so rather than invent one.

Inventors

Unusual pattern to flag: This is not the fire‑sale pattern the brief describes (all inventors leaving before a portfolio dump). It is the opposite and more notable: two of the three inventors, Chishti and Wen, later left Align to build a competitor (OrthoClear) — and the '876 patent was among the Align patents Align then asserted against them at the ITC in 2006. The inventors' departures did not disrupt Align's chain of title; the assignment to Align (recorded 2002) was already perfected and was never unwound.

Original assignee

• Entity on the issued patent: Align Technology, Inc. — a Delaware corporation; at the relevant time located at 881 Martin Avenue, Santa Clara, CA 95050 (later 2560/2820 Orchard Parkway, San Jose, CA 95131).
• Product embodying the claims: Yes. Align conceived and shipped the Invisalign clear‑aligner system — the very "incremental position adjustment appliances" and computer‑generated staged treatment plans the '876 claims are directed to. The patent describes the appliance as a polymeric shell whose cavity geometry corresponds to each intermediate tooth arrangement (US 6,729,876, Fig. 2C / "polymeric shell 111").
• Primary line of business: design, manufacture and sale of orthodontic clear aligners and intra‑oral scanners (medical devices); publicly traded (NASDAQ: ALGN).
• Current status: Operating, solvent, and still the assignee. No bankruptcy, no acquisition, no dissolution. Align never filed for bankruptcy protection (the closest event in the record was the 2006 OrthoClear settlement, in which Align paid OrthoClear $20M — i.e., Align was the purchaser, not a distressed seller).

Assignment timeline

Search returned one recorded assignment in this chain. There is no post‑issuance transfer — no NPE, no security interest, no merger, no change of name.

• executed ~2002‑01‑09 / recorded 2002‑01‑09 — Reel/frame not retrievable (Assignment Center page did not render; recorder is the USPTO Assignment Division, Office of Public Records)
  • Conveyance: Assignment (recorded brief: "ASSIGNMENT OF ASSIGNOR'S INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: Chishti, Muhammad; Choi, Woncheol; Wen, Huafeng (inventors)
  • Assignee: ALIGN TECHNOLOGY, INC. (Delaware corporation)
  • Correspondent: Not surfaced in the records I could retrieve. (Note: the prosecution agent of record is Townsend and Townsend and Crew LLP / Bao Tran; the "ALIGN TECHNOLOGY, INC." address block is the only assignee‑side addressee visible. I cannot confirm the assignment‑recording correspondent, so I will not name one.)
  • Context: Ordinary inventor→employer assignment perfecting title; this is the foundational transfer that gives Align clean standing. It is the only recorded link.

Related‑but‑distinct recording to avoid a mis‑attribution (explicitly flagged):
Google Patents Legal Events on other Align patents (e.g., US 7,819,659) show an "INTELLECTUAL PROPERTY TRANSFER AGREEMENT; ASSIGNORS: ORTHOCLEAR HOLDINGS, INC.; ORTHOCLEAR PAKISTAN PVT LTD.; WEN, HUAFENG; REEL/FRAME 018746/0929," recorded 2006‑10‑13. That is the OrthoClear‑portfolio‑to‑Align conveyance executed under the October 2006 global settlement. It does not appear to be recorded against US 6,729,876 (Align already owned '876, so there was nothing for OrthoClear to assign on this patent), and I found no evidence it was recorded against '876. I am calling it out only so it is not mistaken for a transfer in this chain.

Cross‑reference check: Align's own Google Patents Legal‑Events record for '876 lists only the 2002‑01‑09 "ASSIGNMENT OF ASSIGNOR'S INTEREST" — consistent with a single owner for the patent's entire life. SEC filings (Align 10‑K/8‑K) describe Align asserting the '876 patent (ITC 337‑TA‑562) rather than selling or licensing it out, which corroborates that Align retained title.

If you need the exact reel/frame and correspondent for the 2002‑01‑09 recording, the authoritative pull is a direct query at https://assignment.uspto.gov/patent/index.html (search patent 6729876) or https://assignmentcenter.uspto.gov/ — the assignee record should return a single hit, reel ~012‑013xxx, Correspondent block listing Align's then‑outside IP counsel (likely the same firm that handled contemporaneous Align recordings, e.g., the 013235/0606 recording for App. 10/225,889). I could not verify the exact frame, so I am not asserting it.

Timeline diagram

timeline
    title Ownership of US 6729876
    1999 : Priority application filed 09 313 289
    2001 : CIP application 09 943 097 filed
    2002 : Inventors assign to Align Technology
    2004 : Patent US 6729876 issued to Align
    2006 : Align asserts patent at ITC 337 TA 562
    2006 : Global settlement with OrthoClear
    2019 : Patent expires

NPE / troll-pattern signals

1. Shell‑entity transfer — Not present. The only recorded assignee is ALIGN TECHNOLOGY, INC., an operating medical‑device company, recorded 2002‑01‑09. No name‑suffix "IP/Holdings/Licensing/Ventures" entity appears in the chain; there is no second link to examine.

2. Known asserter in the chain — Not present. Align Technology appears on none of the referenced NPE registers (Acacia, Marathon, Intellectual Ventures, Wi‑LAN, Vringo, Pendrell, Round Rock, etc.). The chain has one assignee and it is the original operating company.

3. Repeat correspondent across the chain — Not present / insufficient data. There is only one recorded assignment, and its correspondent field was not retrievable. A single, unrecovered correspondent entry cannot establish a recurrence signal (and the brief correctly warns that even one appearance is not a finding).

4. Cascading transfers — Not present. One assignment only; no chained LLCs, no multiple transfers within 24 months, no shared correspondent addresses to compare.

5. Pre‑litigation transfer — Not present. The '876 patent was asserted by Align itself in ITC Inv. 337‑TA‑562 (complaint filed 2006‑01‑11), and its title had been with Align since 2002‑01‑09 — i.e., no transfer preceded the suit; no "standing cleanup" or venue‑shopping assignment exists.

6. Bankruptcy fire‑sale — Not present. Align has never been in bankruptcy. The 2006 event was a settlement in which Align paid out ($20M to OrthoClear Holdings) and received OrthoClear's IP — the opposite of a distressed sale.

7. Privateering — Not present. Align litigated its own patents directly (ITC 337‑TA‑562; N.D. Cal.; W.D. Wis.), not through a proxy NPE. The competitor it sued (OrthoClear) was founded by its own ex‑founders, which is direct enforcement, not privateering.

8. Defensive aggregator (anti‑NPE) — Not present. The chain does not end at RPX, AST, LOT, Unified, or OIN. (Note: the '876 patent now appears as Petitioner's prior art in ClearCorrect's IPR2025‑00815/00816 — Exhibit 1005 — but that is third‑party challenge use, not an assignment.)

Verdict

Operating‑company assertion.

Justification: The permanent, sole recorded assignment is the 2002‑01‑09 inventor‑to‑Align Technology, Inc. conveyance, and no subsequent assignment, LLC, security interest, or NPE ever appears in the chain. Align is an operating medical‑device company that ships the Invisalign system embodying the claims and asserted this very patent directly and in its own name in ITC 337‑TA‑562 (claims 1–22 and 28) on 2006‑01‑11, with no intervening transfer. Every enumerated NPE/troll signal is not present, so the activity is genuine competitor enforcement by the original owner rather than an NPE pattern.

Verification link: https://assignment.uspto.gov/patent/index.html → search patent number 6729876 (mirror: https://assignmentcenter.uspto.gov/). Expected result: a single "Assignment of Assignor's Interest" recorded 2002‑01‑09 to Align Technology, Inc. — retrieve the reel/frame and correspondent block at source to close the one remaining gap in this report.

I'll research the prior-art citations for US 6,729,876. Let me run several searches.

Let me get the full front-page citation lists and foreign references.

Prior Art Cited in U.S. Patent No. 6,729,876 — "Tooth Path Treatment Plan"

Identification (no auto-correction): the number as given, 6729876, resolves to US 6,729,876 B2, Chishti / Wen / Choi, Align Technology, Inc., filed 2001‑08‑29, priority 1999‑05‑13, granted 2004‑05‑04, 31 claims. Sources: Google Patents (https://patents.google.com/patent/US6729876/en), FreePatentsOnline (https://www.freepatentsonline.com/6729876.html), and the granted‑patent facsimile used as Petitioner's Ex. 1005 in IPR2025‑00815/‑00816 (https://www.docketalarm.com/cases/[PTAB](/ptab)/IPR2025-00816/ClearCorrect_Operating_LLC/04-12-2025-Petitioner/Exhibit-1005-US_6,729,876_Chishti_876/). Building on the earlier sections, I do not repeat bibliographic, claim‑overview, or litigation content — I extend it with the citation inventory and a § 102 mapping.

0. Important methodological caveat (read first)

The "References Cited" block on the face of a U.S. patent lists art the examiner or applicant considered. It does not state which reference was applied against which claim. Neither Google Patents, FreePatentsOnline, nor the Ex. 1005 facsimile publishes the examiner's per‑claim rejection mapping for the '876 patent. Therefore the "which claim(s) it potentially anticipates" column below is my analytical assessment, not a record of an actual USPTO rejection, and is flagged accordingly. Where I could not verify a filing date or a foreign country code, I say so rather than guessing.

Legal framework used (the '876 patent is pre‑AIA):

Because the '876 patent is a CIP of App. Ser. No. 09/313,289 (US 6,318,994), the critical date is claim‑limitation‑specific: limitations carried over from the parent get 1999‑05‑13; limitations new to the 2001 CIP get 2001‑08‑29. This materially affects which references are even prior art, and I flag it where relevant.

1. U.S. patent references cited on the face of '876

All are "Date of Patent" (grant) dates as listed. Descriptions are my summaries drawn from the cited titles and the patent's own background discussion.

1A. Align / immediate‑predecessor art (strongest § 102 significance)

1B. Computer‑aided dentistry / 3D scanning and modeling art (§ 102(b) — all pre‑1998‑05‑13)

1C. Ormco / Andreiko custom‑appliance art (§ 102(b)) — the principal pre‑Align "custom appliance from a digital model" family

Potential § 102 relevance: collectively these teach deriving a custom orthodontic appliance set from a digitized model of the patient's teeth — relevant to the "generating the malocclusion treatment plan" and "generating an appliance" limitations, but they do not disclose a library of predetermined tooth‑movement patterns.

1D. Positioner / aligner manufacture art (§ 102(b))

Potential § 102 relevance: relevant only to the "polymeric shell appliance" and "produce successive appliances" claims (e.g., claim 8 and the fabrication‑machine dependent claims 25–26). None discloses automated staging.

1E. Miscellaneous

2. Foreign patent documents cited

These appear on the '876 face in the "Foreign Patent Documents" block, reproduced literally as the facsimile renders them (Ex. 1005 shows "2369 828," "WO94/10935," "WO98/32394"):

3. Non‑patent literature cited ("Other Publications")

4. Most relevant art, ranked (§ 102 focus)

1. US 5,975,893 (Chishti et al.) — § 102(e), filed 1997‑10‑08. The only cited reference that discloses a complete digital‑treatment‑plan → staged aligner series → fabrication flow. Discloses the "series of successive tooth arrangements" and appliance‑producing elements of claims 1, 21, 24, 28; the open question is whether it discloses the "library of predetermined tooth treatment patterns" that every independent claim of '876 recites. My assessment: strong § 103 art; a facially weak § 102 anticipation absent a pattern‑library disclosure — but this is also the reference Align has argued (and the Board credited in the '444 IPR) teaches away from "round‑tripping."

2. US 6,217,334 (Hultgren) and US 6,152,731 (Jordan) — § 102(a)/(e). Scanning‑to‑digital‑data and digital articulation/occlusion, respectively. Best mapped to the data‑acquisition and final‑position/occlusion dependent claims.

3. US 5,605,459 (Kuroda), US 5,607,305 & US 5,587,912 (Andersson), US 5,338,198 (Wu), US 5,452,219 (Dehoff), US 5,011,405 (Lemchen), US 5,342,202 (Deshayes), US 5,340,309 (Robertson), US 5,273,429 (Rekow) — § 102(b) background establishing the state of computer‑aided dentistry (scanning, 3D modeling, occlusal modeling, fabrication). Relevant primarily to the "generating a three‑dimensional model for the teeth" and "control a fabrication machine" limitations, not to the pattern‑selection core.

4. Andreiko/Ormco family — § 102(b). "Custom appliance from a digital model," but derives the appliance geometrically, not by selecting from a library of movement patterns.

5. Kesling (1946) and the positioner/aligner‑manufacture art — the closest prior‑art language for the "predetermined pattern" concept, but wholly non‑computerized.

Bottom line on § 102: On the face of the record, no single cited reference appears to anticipate the independent claims, because each independent claim (1, 21, 24, 28, 30, 31) contains the "select a tooth treatment pattern from a library of predetermined tooth treatment patterns" element that the cited scanning/modeling/appliance art does not teach. The cited references are predominantly § 103 background art. I could not locate a per‑claim examiner rejection map for '876, so this is analytical, not documentary.

5. A live, non‑obvious "prior art" role for this very patent (flag)

In the current IPR2025‑00815 / IPR2025‑00816 family (ClearCorrect v. Align), US 6,729,876 is itself the prior‑art reference (Ex. 1005, "Chishti‑876"), not the challenged patent. Per the PTAB paper available at https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1557670](/patent/1557670)/download-documents..., Align argued — and the Board reportedly credited in the related '444 IPR — that Chishti‑876 "teaches away from round‑tripping" and disparages moving a tooth farther than necessary. That is a § 103 "teaching away" position, and it is a useful cross‑check on the § 102/§ 103 character of the '876 disclosure: it is being used as disclosing pattern‑library treatment plans (supports § 102/§ 103 against others) while simultaneously limiting obviousness combinations.

6. Confidence and items to verify

High confidence: the identity of the patent; that the "References Cited" inventory above reflects the '876 face as shown in FreePatentsOnline and the Ex. 1005 facsimile; the grant dates transcribed for the § 1A–1D entries; the presence of Chishti‑876 as Ex. 1005 in IPR2025‑00815/‑00816.

Moderate confidence: the brief descriptions of the very old/foreign items (esp. 2369 828, 4,505,673, 3,860,803, WO 94/10935, WO 98/32394), which I could not independently open within the search budget; the claim‑number mapping (which relies on the previously generated section's note that intermediate independent‑claim numbering — 21 and 24 — is inferred, not read verbatim).

Explicit uncertainties / corrections to flag:

• I could not retrieve the USPTO examiner's actual per‑claim rejections/allowance reasons for '876, so the § 102 column is my assessment. A USPTO PatentCenter/IFW file‑wrapper pull (Application 09/943,097) would give the authoritative rejection map.
• Filing dates for Hultgren '334 and Jordan '731 were not verified, so their precise § 102(e) status against the 1999‑05‑13 priority is stated conditionally.
• The country code for 2369 828 is unresolved in the sources reviewed; I have deliberately not guessed it.
• Potential internal discrepancy to note: the earlier "Patent summary" section lists the movement‑pattern library as including "all equal, A‑shaped, V‑shaped, M‑shaped, W‑shaped, symmetric staircase, asymmetric staircase, and equal‑equal," but the granted specification text fetched here (Figs. 14–20B and the Summary) actually implements only all‑equal (X‑type), A‑shaped, V‑shaped, pre‑equal/equal, random, left‑shift, right‑shift, and XX (equal‑equal) paths. If the "M‑shaped/W‑shaped/symmetric‑asymmetric staircase" list is being relied on for any claim‑charting, it should be re‑verified against the granted claim text, as the routines in the specification do not appear to include M‑/W‑/staircase calculators. This is a discrepancy I am flagging rather than auto‑resolving.

I'll research the prior-art landscape and any §103 challenges specific to this patent before building the analysis.

Useful leads. Let me dig into the specific prior-art references and any PTAB record directly addressing the '876 patent.

Obviousness Analysis — U.S. Patent 6,729,876 ("Tooth path treatment plan")

Identifier checked literally: 6729876 → US 6,729,876 B2, Chishti, Wen & Choi, Align Technology, Inc., App. 09/943,097 filed 2001‑08‑29, granted 2004‑05‑04, expired 2019‑06‑21. No auto-correction applied. (Google Patents record: https://patents.google.com/patent/US6729876/en)

Scope note on sources. The "Prior Art" material available to me consists of (a) the references cited on the face of the '876 patent itself (front‑page "References Cited": e.g., 3,660,900 Andrews; 3,860,803 Levine; 4,348,178 Kurz; 4,504,225 Yoshii; 4,755,139 Abbatte; 4,793,803 Martz; 4,798,534 Breads; 4,856,991 Breads…; foreign: DE 2369828, WO 94/10935, WO 98/32394), (b) the prior art named in the '876 specification, and (c) the art actually deployed against Align patents in the PTAB/litigation record (Sachdeva‑918, Snow‑482, Hultgren‑334, Kesling, Becker, Chishti‑511/‑876). The Google Patents "References Cited" list is truncated in my fetch (it breaks off at 4,856,991), so the full front page was not machine‑readable; where I rely on a reference's date or content I flag it.

1. Threshold: which §102/§103 date and statute govern

App. 09/943,097 was filed 2001‑08‑29 → pre‑AIA §102/§103 apply (AIA §3(n)(1) reaches only applications filed on/after 2013‑03‑16). The '876 patent is a CIP of App. 09/313,289 (filed 1999‑05‑13, now US 6,318,994, same title, same inventors, Align‑owned).

Under PowerOasis/In re Chu, §120 benefit is claim‑by‑claim and limitation‑by‑limitation. The CIP added, among other things, Figs. 10–13 (X/A/V/XX movement diagrams) and Figs. 14–20B (the pattern‑selection and recursive frame‑subdivision routines), plus the express statement that "the system plans tooth path in accordance with a library of movements." If that subject matter is not carried in the 1999 parent, the claimed "library of predetermined tooth treatment patterns" gets only the 2001‑08‑29 date. That single question controls the whole prior‑art field:

I recommend the second scenario as the primary working hypothesis, because the pattern‑library limitation is precisely the CIP's new matter. I flag this rather than assert it: I could not retrieve App. 09/313,289's as‑filed text to confirm whether the pattern library is in the parent.

Critical §103(c) caveat (this is the single biggest trap in any '876 obviousness case). Pre‑AIA §103(c) disqualifies, for §103 purposes, subject matter that qualifies as prior art only under §102(e)/(f)/(g) and that was commonly owned when the invention was made. Align's sibling patents — 6,471,511 (filed 1998‑10‑08, issued 2002‑10‑29), 6,450,807, 6,227,850, 6,217,325, 6,318,994 (issued 2001‑11‑20) — all issued after both candidate critical dates, so they are §102(e)‑only art and, being commonly owned by Align, are disqualified as §103 references against '876. Petitioners in IPR2017‑01829 and IPR2025‑00815/816 could freely use Chishti‑511 against the 2006‑priority patents (there it is §102(b) art), but that reasoning does not transfer back to '876. Any ground built on "Chishti‑511 + Chishti‑876" against '876 itself is legally defective at the threshold.

2. What the claims require (for §103 mapping)

From the granted claim set (per Patexia's reproduction, https://patexia.com/us/patent/06729876):

• (1)(A) selecting a tooth treatment pattern from a library of predetermined tooth treatment patterns;
• (1)(B) generating the malocclusion treatment plan implementing the selected pattern;
• (1)(C) generating a series of successive tooth arrangements from a first to a second arrangement.
• Independent variants: claim 21 (data sets), claim 24 (computer‑readable medium), claim 28 (staging + controlling a fabrication machine), claim 30 (processor/display/storage system), claim 31 (means‑plus‑function on a digital model).
• Key dependents: collision‑free shortest path (3); clinical prescriptions — space closure, reproximation, dental expansion, flaring, distalization, lower incisor extraction (4–5); stage division with per‑stage movement caps (6–7, incl. 0.2–0.4 mm and 5–10° per stage); appliance per stage (8); named patterns (X/all‑equal, A, V, M, W, symmetric/asymmetric staircase, equal‑equal) (14–18); arrays indexed by stage (19–20); fabrication‑machine code incl. laser‑curing resin (25–27).

Note the patent's own admissions that materially narrow the non‑obviousness case: "On average, each aligner should be able to accomplish move about 0.25‑0.33 mm and to rotate about 5‑10 degrees within a 2‑week period"; "various movements such as distalization, tip, and torque can have separate parameters"; and "the algorithm schedules treatment paths by drawing upon a database of preferred treatments for exemplary tooth arrangements… constructed over time by observing various courses of treatment." Those are applicant‑side characterizations of the claimed subject matter as conventional tooling.

3. Prior‑art inventory and what each element supplies

About Chishti‑511 / Chishti‑876 as references: both are unusable here. Chishti‑511 issues after the critical date and is §103(c)‑disqualified; Chishti‑876 is the patent on the stand. Note also that the Board has repeatedly held that Chishti‑876 itself "teaches away" from round‑tripping (IPR2017‑01829 institution decision, Ex‑1008 at 11‑12; PO Preliminary Response, IPR2025‑00815/816/817/820, at §§III.B). That finding cuts against the use of '876 as art against others; it cannot be turned into a defense of '876's own claims, because a patent's specification cannot teach away from its own claims. It does, however, tell us what '876's core disclosure is: a database of established treatment patterns (Pet. 1, IPR2025‑00816: "Chishti‑876 discloses a database of established treatment patterns for creating treatment plans").

4. Proposed §103 grounds

Ground 1 — Sachdeva‑918 as primary, in view of Snow‑482 and Andreiko‑type "prescription/template" art (targets claims 1, 21, 24, 28, 30, 31 and broad dependents)

• Elements (B) and (C): Sachdeva‑918 discloses determining a 3‑D direct path per tooth from actual and desired digital models and simulating movement over a sequence of stages, with conflict detection and resolution and treatment constraints — i.e., generating a malocclusion treatment plan and a series of successive tooth arrangements.
• Element (A): Andreiko‑family art discloses computing appliance placement by reference to a predefined "ideal"/prescription archform template chosen from a defined set applied to the individual patient; the orthodontic art already used named "prescriptions" (standard bracket/positioning schemes) as a fixed menu rather than a bespoke solution. Adding a menu of movement schedules to a treatment‑planning engine is the same design move.
• Motivation: KSR‑type rationales — (i) predictability and reproducibility ("conversion of the practice of orthodontics from an art to a science," Sachdeva‑918's own stated goal); (ii) clinical efficiency, since pattern‑by‑pattern staging eliminates manual, case‑by‑case staging (the '876 patent's stated advantage); (iii) both references are in the same field of endeavor and are reasonably pertinent to the same problem (aligner treatment planning) — the analogous‑art predicate is satisfied on the face of it.

Ground 2 — Sachdeva‑918 + Snow‑482 + Hultgren‑334 + Kesling (targets appliance/fabrication claims 8–13, 25–27, 29)

Sachdeva/Snow supply the treatment plan and digital data sets; Hultgren supplies fabricating successive positive models from those data sets; Kesling/Warunek supply producing a negative polymeric shell (positioner) over each model. This is precisely the combination the Board instituted and then held unpatentable in IPR2016‑00270 (Snow + Hultgren + Kesling → '037 patent claims), so the motivation analysis is already Board‑tested: "the natural progression of using digital technology to assist in the fabrication of dental appliances." Laser‑curing of photosensitive resin (claim 26) is standard stereolithography art (Hull‑type) and the '876 specification itself describes it generically.

Ground 3 — Sachdeva‑918 + Becker (targets the "sequencing" dependents and the named‑pattern dependents 14–18)

The dependent claims recite exactly the alternatives a clinician chooses among: move everything together (all‑equal), anterior‑first (A), posterior‑first (V), two‑phase (equal‑equal/XX), and stepped/staircase schedules. Sachdeva‑918 supplies staged movement with priority‑tooth ordering (its "priority tooth… moved independently of other tooth movement or in parallel"), and Becker supplies deliberately moving one tooth out of another's path — the same clinical decisions. A POSITA designing a staging engine would enumerate precisely this small, closed set of schedules (KSR: "a finite number of identified, predictable solutions"). The patent's own admissions of a "database of preferred treatments" and "movements such as distalization, tip, and torque [having] separate parameters" make the enumeration routine optimization.

Ground 4 — Sachdeva‑918 (collision) + Gottschalk OBBTree (targets claims 2–3 and the collision‑detection dependents)

Claim 3's collision‑free shortest path is met by Sachdeva's direct path + conflict resolution; the specific OBB‑tree recursion the '876 specification adopts is verbatim prior art (Gottschalk 1996). The "neutral plane / signed‑distance / sum ≤ 0" test of Figs. 8–9 is a z‑buffer/depth‑map proximity test, a standard computer‑graphics technique a POSITA would substitute for OBB‑tree triangle intersection when speed matters (express motivation: the specification itself justifies it by resolution/performance).

Ground 5 — Routine‑optimization attack on the numerical and data‑structure dependents (claims 7, 19–20)

Claim 7 (≈0.2–0.4 mm translation, 5–10° rotation per stage) and claim 19 (array indexed by stage/tooth) are, by the applicant's own specification, conventional parameters ("about 0.25‑0.33 mm… 5‑10 degrees within a 2‑week period") and a conventional data structure. Under In re Aller/KSR, discovering optimal or workable parameter values is not inventive where the parameters are result‑effective and the methods of varying them are known.

5. Anticipated defenses and how the grounds should be built to survive them

1. Priority/§103(c) attack on the grounds themselves. Anticipate Align arguing that (a) the claims do get 1999 benefit (which removes Sachdeva‑918), and (b) any Align‑owned reference is §103(c)‑disqualified. Response: build the ground on third‑party art only (OraMetrix/Sachdeva‑918, Snow, Hultgren, Andreiko/Ormco, Kesling/Warunek, Gottschalk). Do not lean on Chishti‑511/‑876 or the parent 6,318,994.
2. "Library of predetermined tooth treatment patterns" is the point of novelty. The strongest non‑obviousness argument is that nothing in the art stores a selectable menu of movement schedules. The patent‑owner will point out that the examiner allowed over the 3‑D‑scanning/positioner art. Response: the "prescription"/ideal‑archform‑template art (Andreiko/Lemchen) plus the '876 specification's own admission of a "database of preferred treatments" closes this gap; in the alternative, the claim construction of "library" (any collection of pre‑stored patterns) should be pressed, and the dependent claims' pattern names treated as species of a genus that was itself known.
3. Teaching away / criticality. '876 disparages "round‑tripping" and prescribes the minimum‑movement path. That is irrelevant to its own validity, but a petitioner using the A/V/X patterns must show the schedules, not the round‑trip steps, are what is claimed.
4. Secondary considerations. Align can point to the Invisalign franchise, the 2006 OrthoClear consent order and $20M payment (https://aligntech.gcs-web.com/node/13716/html), and the CAFC's 2006 ruling invalidating claims of Align's 6,398,548 and 6,554,611 as obvious (10‑K: https://www.sec.gov/Archives/edgar/data/[1097149](/patent/1097149)/000110465907018240/a07-5886_110k.htm) — which, notably, is adverse to a strong secondary‑considerations story. Nexus is the vulnerable point: commercial success is attributable to the aligner system as a whole, not to the claimed "select‑from‑a‑library‑of‑patterns" feature.
5. Prosecution‑history benefit. No examiner‑considered third‑party art appears to address pattern‑library selection, so Grounds 1–4 are not cumulative for §325(d)/§102‑prior‑art purposes. No ex parte reexamination of '876 was ever granted (the 2006 reexam campaign covered 5,975,893; 6,398,548; 6,309,215; 6,705,863; 6,217,325; 6,318,994 and IPRs of 6,629,840; 6,685,469 — https://www.sec.gov/Archives/edgar/data/1097149/000110465907018240/a07-5886_110k.htm).

6. Bottom line by claim group

Confidence: high on the §103(c) disqualification of Chishti‑511/‑876‑family references (mechanically follows from pre‑AIA §103(c)); high on Sachdeva‑918's content (verified verbatim claim text and specification excerpts); moderate on the effective‑date analysis, since I could not read the 1999 parent, and on the exact filing dates of Snow‑482 and Hultgren‑334, which must be confirmed against the applicable critical date before any ground is finalized.

Items I could not verify and therefore do not assert: (i) whether the pattern library appears in App. 09/313,289; (ii) Snow‑482's and Hultgren‑334's precise §102(e) dates; (iii) the content of WO 94/10935 and WO 98/32394 as cited on the '876 face; (iv) whether any 2025–2026 PTAB proceeding names '876 itself as the challenged patent — everything I found uses '876 only as prior art (Ex‑1005/Ex‑1004 in IPR2025‑00815‑00821 and IPR2017‑01829), which is consistent with, and does not contradict, the earlier sections of this analysis.