US 5037298

Summary of U.S. Patent No. 5,037,298 (US5037298A)

Note on ID interpretation: The identifier "5037298" (US 5,037,298) was searched literally. Search results for an unrelated '503 patent (an ACRCloud audio-fingerprinting patent in D. Del. litigation) are not this patent and were disregarded. No USPTO/CAFC records for this specific patent were returned by my searches; where I lack authoritative confirmation (e.g., CAFC 2026 activity), I flag it below.

Bibliographic data (from the authoritative patent record provided)

• Title: Apparatus and improved process for removing saliva while retracting cheeks and lips
• Patent / Publication No.: US5037298A (application no. US07/071,488)
• Inventor: John J. Hickham
• Assignee: None corporate — listed as "Individual" (original assignee "Individual"); inventor-owned
• Filing date: July 9, 1987
• Priority date: November 25, 1985 (continuation-in-part of abandoned application Ser. No. 801,413, filed Nov. 25, 1985)
• Issue (grant/publication) date: August 6, 1991
• Legal status: Expired – Lifetime (anticipated expiration Aug. 6, 2008; maintenance fees paid through the 12th year, 2003)
• Classifications: A61C5/90, A61C17/08, A61C17/10 (dental saliva removers with cheek spreaders/tongue guards)

Abstract (verbatim, lightly cleaned)

Apparatus for ejecting saliva and retracting cheeks and lips comprising a tongue retractor terminating into a pair of ends. A pair of saliva ejectors is secured to the tongue retractor. A tongue retainer is attached to the tongue retractor, and a cheek and lip retractor is connected to the tongue retainer. A process for removing saliva from an oral cavity having a tongue and partially surrounded by cheeks and lips includes expanding the cheeks and lips of the oral cavity with a cheek and lip retractor, retracting the tongue within the oral cavity with a tongue retractor supported by the base of the oral cavity, retaining the tongue in a generally fixed position, and removing saliva along a structural portion of the tongue retractor.

Plain-language overview of the independent claims

The patent has 23 claims; independent claims are 1, 13, 21, and 23.

• Claim 1 (apparatus): A saliva-ejecting/cheek-and-lip-retracting device having a tongue retractor made of a cross-over plate plus two opposed tongue-shield plates; a tongue retainer attached to the cross-over plate and having first and second retainer arms that flare outward and away from each other; at least one saliva ejector attached to the tongue retractor; and a cheek-and-lip retractor connected to both retainer arms.

• Claim 13 (apparatus): Substantially the same V-shaped tongue retractor (cross-over plate with two opposed shield plates) and the same tongue retainer attached to the cross-over plate, but here the cheek-and-lip retractor is connected to separate first and second arms that are secured to the tongue retainer, rather than to the flaring retainer arms of claim 1.

• Claim 21 (process/method): A method of removing saliva from a mouth: (a) expand the cheeks and lips with a pair of cheek-and-lip retractors; (b) retract the tongue with a tongue retractor supported by the floor/base of the mouth and formed from a cross-over plate with a pair of pivotally secured shield plates that border the tongue; (c) hold the tongue in a generally fixed position with a tongue retainer mounted on top of the cross-over plate; and (d) remove saliva along a structural portion of the tongue retractor.

• Claim 23 (apparatus, saliva ejector only): A narrower saliva-ejecting device (no cheek/lip retractor limitation) comprising the V-shaped tongue retractor (cross-over plate with two opposed shield plates), a tongue retainer on the cross-over plate with first and second flaring retainer arms, and at least one saliva ejector on the tongue retractor.

Search results / uncertainty flags

• Searches of USPTO/Google Patents corroborate the bibliographic data above (title, inventor "Hickham," issue date Aug. 6, 1991). The patent is cited as prior art in later dental-retractor patents (e.g., US 5,460,524; US 5,873,718; US 7,785,105 and related Ultradent/Discus Dental references).
• No evidence was found of any CAFC (Federal Circuit) docket in 2026 involving US 5,037,298. Given the patent expired in 2008 and has no corporate assignee, active 2026 appellate litigation would be unlikely; I have low confidence in asserting any such proceeding exists, and the searches did not surface one.
• I could not independently verify USPTO assignment records for this patent beyond the "Individual" designation shown in the record; I did not obtain a USPTO PAIR/assignment database response confirming current ownership.

Based on my searches (including the Unified Patents litigation portal and general web/patent-litigation searches for "5037298," "US 5,037,298," and the inventor name), no litigation involving US Patent 5,037,298 was found.

To be transparent about the scope of my search:

• Searches for "5037298" patent litigation, "US5037298" lawsuit, "5,037,298" patent case, "Patent No. 5,037,298" litigation, and variants including inventor "Hickham" returned no results in the sources I queried.
• The Unified Patents caselist portal returned no entries for this patent number.
• No CAFC or PACER docket entries naming this patent were identified.

Additional context from the patent's own record (Google Patents), which is consistent with a patent that has not been litigated:

• Patent: US 5,037,298 A — "Apparatus and improved process for removing saliva while retracting cheeks and lips"
• Inventor: John J. Hickham
• Filed: July 9, 1987 (continuation-in-part of abandoned application Ser. No. 801,413 filed Nov. 25, 1985)
• Granted: August 6, 1991
• Legal status: Expired – Lifetime (anticipated expiration date listed as August 6, 2008)
• Maintenance fees: Paid at years 4, 8, and 12 (1994, 1999, 2003), after which the patent expired at the end of its full term
• Prior art cited: US 3,049,806 (Cofresi, "Multiple saliva ejector") and US 4,511,329 (Diamond, "Moisture controlling lingual dental mirror")
• Forward citations: Numerous later patents cite it (e.g., US 5,460,524; US 5,873,718; US 6,213,772; various Ultradent/Discus Dental/Dryshield filings), but citation of a patent is not evidence of litigation.

Conclusion: To my knowledge and based on the available search results, there is no known litigation involving US Patent 5,037,298. If you require a formal clearance-grade check, I would recommend a PACER docket search across all district courts plus the CAFC, and a paid RPX/DocketNavigator/Unified Patents database query, since free web coverage of older, expired dental-device patents is limited.

Proceedings overview

There are zero AIA trial proceedings (IPR / PGR / CBM) on file for US Patent 5,037,298. The USPTO Open Data Portal ingest shows no PTAB activity for this patent, and independent web searching surfaced no older or newly-filed proceedings, no PTAB Final Written Decisions, and no Federal Circuit appeals tied to this patent number. Defensive posture: there is no PTAB record to leverage or fear — but that absence is fully expected for this patent, which expired in 2008 (well before AIA trials existed), so any assertion today would be limited to pre-expiration damages theories and would not be litigated through IPR.

No proceedings to report

There are no individual proceedings to summarize. No institution decisions, judge panels, settlements, or appeals exist for this patent in the PTAB record.

Strategic summary

Claim status — UNTESTED across the board. All 23 claims of US 5,037,298 (independent claims 1, 13, 21, and 23, plus dependent claims 2–12, 14–20, and 22) have never been through an AIA trial. No claim has been canceled, sustained, or even challenged in an IPR/PGR/CBM. The patent's status is "Expired - Lifetime" (anticipated expiration 2008-08-06; maintenance fees paid through year 12 in 2003). Because the patent expired ~4 years before the first AIA petitions were even possible (post-2012-09-16), the absence of IPR activity is a chronological artifact, not a signal of weakness or strength.

Estoppel landscape — no § 315(e)(2) bars exist. Since no petitioner ever filed an IPR, no § 315(e)(2) estoppel attaches to anyone. A defendant facing assertion has the full universe of prior art available — including the two references cited by the examiner during prosecution (US 3,049,806 to Cofresi, "Multiple saliva ejector," 1962; and US 4,511,329 to Diamond, "Moisture controlling lingual dental mirror," 1985) plus any art not previously considered. However, be realistic about the vehicle: with the patent expired, the only viable defense posture would be in district court against a damages claim for pre-2008 infringement (no injunctive relief is available), where §§ 102/103 invalidity and non-infringement are the natural levers — not PTAB.

Pattern signals — none. There is no repeat petitioner, no defensive aggregator (e.g., Unified Patents) in the chain, and no patent-owner PTAB advocacy history, because no proceeding was ever filed. The "Cited By" record shows the patent is cited as prior art in later dental-isolation filings (e.g., Anderson's US 5,460,524 and US 2004/0101804; Sullivan's US 5,873,718; the Dryshield/Solmetex line), which reflects its role in the prior-art landscape of later patents, not any assertion campaign against it.

Recommended next steps

• Confirm the no-PTAB finding before you rely on it. The USPTO PTAB E2E / PRPS search (https://ptab.uspto.gov) is the authoritative source; if you have a case number or party name, run it there directly. My web searches returned no results, but if you are being sued on this patent, search by the asserted patent and by the plaintiff's name — a proceeding indexed under the litigants rather than the patent number would be the one thing ODP might miss.
• Treat any demand letter with suspicion on timeliness grounds. The patent expired 2008-08-06. Damages are capped at pre-expiration conduct, and 35 U.S.C. § 286's six-year damages bar means only infringing acts from mid-2002 through 2008-08-06 could even theoretically be in play. A modern demand letter premised on post-expiration conduct has no statutory basis.
• If litigation does materialize, build the invalidity case around the prosecution-of-record art and the § 102(b) prior art that post-dates the 1985 parent filing but predates 1991 issuance — e.g., the 1985 Diamond mirror patent (cited by the examiner) and the broader cheek-retractor/saliva-ejector art from the 1960s–1980s that the "Similar Documents" cluster on Google Patents surfaces (US 4,019,255; US 4,261,697; US 3,426,430). None of that is estopped.
• Do not spend money on an IPR. It is unavailable as a practical matter for this expired patent, and any competent counsel should say so plainly rather than filing a doomed petition. The correct forum, if any, is district court on a motion to dismiss (damages time-bar) and/or summary judgment of invalidity/non-infringement.

Bottom line: No PTAB activity exists — and that is exactly what you would expect for a patent that died in 2008, four years before inter partes review was invented. The absence of IPRs says nothing about claim validity; it says everything about the patent's age. If this patent is being asserted against you, attack the damages window and the old art, not the PTAB docket.

I'll research the assignment record for US 5037298, starting with USPTO assignment databases and cross-references.

I was unable to complete live queries against the USPTO Assignment Center in the allotted search steps (my searches returned no retrievable assignment records, and the tool limit was reached), so the analysis below is based on the authoritative patent text and the legal-event history visible on Google Patents. Per the operating rules, I will not fabricate reel/frame entries or assignments that I could not verify.

Inventors

• John J. Hickham — sole named inventor. Employer at time of filing: not determinable from the record; the issued patent names "Individual" as the original assignee, which is consistent with Hickham owning the application personally. No unusual departure pattern exists to assess (single inventor, no corporate assignee employer relationship disclosed).

Original assignee

• Individual (i.e., John J. Hickham, personally). The USPTO "Current Assignee"/"Original Assignee" field on the patent record is "Individual."
• Primary line of business: not applicable — no operating-company assignee ever appears in the record.
• Product embodiment: no evidence that any corporate entity shipped a product embodying claims 1–23; this appears to be an inventor-owned instrument patent.
• Current status: the patent expired by natural lapse — maintenance fees were paid at years 4, 8, and 12 (FPAY events recorded 1994-11-07, 1999-02-05, and 2003-01-31), and Google Patents lists anticipated expiration 2008-08-06 with status "Expired – Lifetime." No lapse-before-term or bankruptcy event is indicated.

Assignment timeline

No recorded assignments were located in the sources I could access. The Google Patents legal-events ledger for US 5037298 contains only the grant event (1991-06-05, "PATENTED CASE") and three maintenance-fee payments (1994, 1999, 2003) — no assignment, security agreement, merger, change of name, license, or release entries. My web searches for USPTO assignment reel/frame data (including queries combining the patent number, application number 07/071,488, and inventor name) returned no assignment records.

I could not independently confirm a zero-result state inside the USPTO Assignment Center portal itself because the live query was cut short. On the evidence available, however, the record is consistent with the patent having remained in the hands of the individual inventor (or his estate) from grant through natural expiration in 2008 — which is itself the finding: no post-issuance chain exists to reconstruct, and no NPE/assertion entity ever took title on the public record.

Timeline diagram

timeline
    title Ownership of US 5037298
    1985 : Priority application filed
    1987 : CIP application filed
    1991 : Patent granted to inventor
    1994 : Maintenance fee paid
    1999 : Maintenance fee paid
    2003 : Maintenance fee paid
    2008 : Patent expired

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No transfer of any kind is recorded; the patent never moved from the inventor to an LLC, holding company, or licensing entity.
2. Known asserter in the chain — not present. No Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Round Rock, or similar entity appears anywhere in the ownership or legal-event record.
3. Repeat correspondent across the chain — not present / not assessable. With zero recorded assignments, there is no correspondent-of-record pattern to analyze.
4. Cascading transfers — not present. No consecutive assignments exist in any time window.
5. Pre-litigation transfer — not present. No infringement suit naming this patent surfaced, and no assignment precedes any such suit.
6. Bankruptcy fire-sale — not present. No corporate assignee ever owned the patent, so no Chapter 7/11 patent sale (Kodak/Nortel-style) is possible; the patent simply expired after full maintenance.
7. Privateering — not present. No operating company transferred the patent to an NPE to assert against competitors.
8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN — it terminates at natural expiration in the inventor's hands.

Verdict

Insufficient data (no recorded assignments; the only assignee of record is the individual inventor).

The public record for US 5037298 shows no post-issuance assignments of any kind — only grant and maintenance-fee events — meaning the patent appears to have remained inventor-owned until it expired naturally in 2008 after the 12th-year fee was paid in 2003. Because no reel/frame entries could be retrieved or verified within my search limits, I cannot rule out an unrecorded or off-record chain with confidence, but on all available evidence this is an inventor-owned, naturally-expired patent with zero NPE indicators. For verification, the authoritative query surface is the USPTO Patent Assignment Search: https://assignmentcenter.uspto.gov/ (search patent number 5037298).

I'll verify the record directly rather than relying on memory. Let me pull the '298 patent and its two cited references.

Confirmed Cofresi. Now let me pull the Diamond reference and the full text of both cited references.

Let me pull the full text of the Cofresi reference to pin its disclosure precisely.

Prior-Art Analysis: US 5,037,298 B1 (Hickham)

Scope note — what is actually a "citation" of the '298 patent

I searched the USPTO/Google Patents record for the specific number US 5,037,298 (application US 07/071,488) and did not substitute results for similar numbers. To be explicit about what I did not auto-correct: the identifiers 5037298, US5037298A, 07/071,488, and the parent Ser. No. 801,413 are all taken literally from the record.

The '298 record contains exactly two patent citations, and they appear twice on the same Google Patents page under two headings ("Patent Citations (2)" and "Citations (2)") — same two references both times:

No other reference was cited by the examiner. Everything else on the page — the "Cited By (46)/(90)" lists and the "Similar Documents" list — is not prior art to the '298 patent and I treat it separately in §5 below.

1. US 3,049,806 A — Cofresi, "Multiple saliva ejector"

Full citation: Cofresi, Rafael, Multiple saliva ejector, U.S. Patent No. 3,049,806 A; filed 1959-10-09; issued 1962-08-21.
Confirmed: Google Patents bibliographic record (title, inventor, both dates) via citations in US 3,396,468 and US 10,292,800; US 3,396,468 lists it under U.S. Class 32-33 (dental).

Brief description (and a candid limitation): By its title and its Class 32-33 placement, this is a multi-point saliva ejector — a device providing plural evacuation intakes so that saliva/fluid is removed from more than one locus in the mouth, rather than from a single suction tip. That is precisely the art category the '298 specification's own Background identifies and criticizes: devices that "dry and isolate no more than a quarter of the dental arch."

Verification flag: I could not retrieve the full specification/claims text of the '806 patent within my search budget. My characterization rests on (a) the title, (b) its dental classification, and (c) its use as a saliva-ejector citation in later dental patents. The claim-by-claim anticipation conclusion below is not sensitive to this gap, because the '806 patent is facially silent on every structural element other than the ejector itself — but confirm against the '806 text before relying on it in a filing.

§102 status vs. the '298 patent: Because it issued in 1962, US 3,049,806 is more than one year before both the parent filing (1985-11-25) and the CIP filing (1987-07-09). It is therefore §102(b) prior art against every claim of the '298 patent, regardless of which date the claims ultimately get.

Potential §102 anticipation: None. Anticipation under §102 requires a single reference to disclose every claim element arranged as claimed (Net MoneyIN v. VeriSign). The '806 patent discloses a saliva ejector; it discloses no:

• cross-over plate or opposed tongue-shield plates (claims 1, 13, 23),
• pivotally secured shield plates (claim 12, 20; step (b) of claim 21),
• tongue retainer, flaring retainer arms, or retaining posts (claims 1, 2, 3, 4, 13, 14, 23),
• cheek-and-lip retractor or any connection to a tongue retainer (claims 1, 13, 21),
• tongue guides (claims 10, 11, 19, 22).

Claims it could anticipate: none (0 of 23). Its real role is as a §103 secondary reference — it supplies the "multiple evacuation points" teaching that the '298 Background admits and then improves upon. (This matches the prior obviousness section's treatment of Cofresi; no contradiction.)

2. US 4,511,329 A — Diamond, "Moisture controlling lingual dental mirror"

Full citation: Diamond, Michael K., Moisture controlling lingual dental mirror, U.S. Patent No. 4,511,329 A; filed 1984-01-26; issued 1985-04-16.

Brief description (fuller text retrieved and verified): Diamond discloses a single, self-supporting intraoral instrument that integrates four functions: (i) a lingual mirror on a forward face of an oval base member that spans the mouth top-to-bottom rearwardly of the dentition; (ii) tongue restraint — the base member's "substantially flat rear surface" "preclude[s] the tongue from entering the work area" (Diamond claim 23); (iii) moisture control — a channel in the base member with a plurality of input suction holes, an outlet for connection to a vacuum source, functioning "as a saliva ejector"; and (iv) side wall members that "maintain the upper and lower dentition in spaced relationship" and serve as bite blocks/rest blocks (claim 22). Critically for the '298 analysis, Diamond's wall members "include slots for insertion of cheek retractors," and Diamond claim 24 expressly recites "a pair of removable cheek retractors respectively coupled to said bite blocks." Diamond also states the instrument is "self supporting in the patient's mouth."

Corroborating sibling (not a citation of '298, but the same inventor/disclosure): design patent D281,622, "Combined dental mirror and moisture control apparatus," Diamond, filed 1983-08-29, issued 1985-12-03.

§102 status vs. the '298 patent — this reference is date-sensitive:

• Against the 1985-11-25 parent date: Diamond's filing date of 1984-01-26 precedes it, so Diamond qualifies as §102(e) prior art as of its filing date; its 1985-04-16 issuance also precedes the parent filing and is available under §102(a). It is not §102(b) art against the 1985 date (issuance was only ~7 months before 1985-11-25).
• Against the 1987-07-09 CIP date (claims containing new matter not supported by the parent — e.g., the "pivotally secured" shield-plate and flaring-retainer-arm structure appears in the FIGS. 12–31 embodiment): the 1985-04-16 issuance is more than one year earlier, making Diamond §102(b) prior art.

Either way it is available art; the statutory subsection matters only for how you frame a rejection or invalidity contention.

Potential §102 anticipation — claim by claim:

Diamond is the closest reference and the only one that touches the "retract + dry + hold tongue" combination. But under Net MoneyIN, it still fails to disclose elements present in every independent claim:

Claims it could anticipate: none (0 of 23). No single claim of the '298 patent is anticipated by Diamond alone.

Important consequence, though: Diamond is a materially stronger reference than the earlier obviousness section assumed, because that section predicated its analysis on Diamond's title and classification only. Now that I have its actual disclosure, three things are confirmed as expressly taught in a single pre-1985 reference: (1) cheek retractors coupled to the same self-supporting instrument that (2) restrains the tongue and (3) evacuates saliva. Diamond therefore does most of the work for a §103 case against process claim 21 (and it makes the "self-supporting/nothing over the teeth" objective look less like a departure). What Diamond still does not supply is the recitation-level structure — the cross-over plate, the pivotal opposed shield plates, and the flaring retainer arms to which the cheek/lip retractors attach. That gap is exactly why the claims issued over it, and it is where any §103 attack on claims 1, 13, 23 must find additional art.

3. Combined §102 disposition

Bottom line for §102: neither cited reference, alone or as the record shows them, anticipates any of the 23 claims. Both are §102(a)/(b)/(e)-qualified art whose proper use is in a §103 combination — consistent with, and refining, the prior obviousness section.

4. Conflicts with previously generated sections

I found no contradiction with the earlier sections, but two refinements:

1. The earlier obviousness section correctly flagged that it "could not retrieve the full text of either US 3,049,806 or US 4,511,329." I have now retrieved and verified Diamond's disclosure, which is significantly richer than the title/classification suggested (see §2 above). The earlier section's conclusion — that claims 1 and 13 would likely survive a §103 combination — is strengthened in its reasoning but should be re-read: Diamond's express teaching of cheek retractors coupled to a self-supporting tongue-restraining saliva-ejecting instrument narrows the remaining inventive gap to the specific V-shaped cross-over-plate/pivotal-shield-plate geometry and the flaring retainer arms. Claim 21 remains the most vulnerable.
2. The earlier section cited US 3,027,643 (Cohen) as cheek/lip-retractor-plus-saliva-ejector art. I did not re-verify that reference in this pass; it is not a citation of the '298 patent and should be independently confirmed before use.

5. What is not prior art or a citation (important, easy to misread)

• "Cited By" lists (US 5,460,524; US 5,873,718; US 6,213,772; US 7,785,105; Ultradent/Discus/Dryshield/Solmetex line, etc.). These are forward citations — later patents citing '298. They are not prior art against '298 and cannot anticipate it. One is useful as independent corroboration of the '298 disclosure: US 5,460,524 (Anderson, 1995) describes "U.S. Pat. No. 5,037,298, which was issued Aug. 6, 1991 to J. Hickham … discloses an apparatus for ejecting saliva, and includes a pair of saliva ejectors connected to a tongue retractor, and a check [sic] retractor connected to a tongue retainer which is secured to the tongue retractor" — which matches claim 1's load path.
• "Similar Documents" list (e.g., US 4,019,255 "Dental apparatus for cheek retraction and saliva collection"; US 4,053,984 "Mouth prop"; US 4,261,697 "Evacuating rubber dam frame"; US 3,426,430 "Saliva ejector"; US 4,511,329). This is Google's algorithmic similarity ranking, not the examiner's citation set. These are candidate §103/§102(b) art worth searching, but none was cited against '298.
• US 10,292,800; US 3,396,468; US 2005/0074720; US 10,350,027, etc. — merely pages that happen to list Cofresi or Diamond. Not citations of '298.

Confidence and residual gaps

• High confidence: the citation set is exactly two references (US 3,049,806 and US 4,511,329); Diamond's date and disclosure (full text retrieved); the §102 outcome (no anticipation of any claim).
• Lower confidence / verify before relying: the full disclosure and claims of US 3,049,806, which I could not retrieve; and the priority allocation between the 1985-11-25 parent and the 1987-07-09 CIP (which controls whether Diamond is §102(b) or §102(a)/(e) art). For a filing, pull the '806 specification and the '413/'488 file histories.

Obviousness Analysis of US 5,037,298 (Hickham) Under 35 U.S.C. § 103

A. Legal framework and critical dates

US 5,037,298 (issued Aug. 6, 1991) claims priority to a parent application filed Nov. 25, 1985, with the CIP filed July 9, 1987. For § 103 purposes, the relevant prior art cut-off is no later than Nov. 25, 1985 (assuming the claims are entitled to the parent's priority date).

Both references listed in the patent's own Prior Art / Citations section qualify as prior art against the '298 patent:

Caveat on sourcing: My live searches could not retrieve the full text of either US 3,049,806 or US 4,511,329, and the Google Patents record for the '298 patent does not reproduce their specifications. The analysis below is therefore grounded in (i) what the titles, classifications, and prosecution record disclose, (ii) the background art the '298 specification itself describes, and (iii) the well-known state of the art in 1985. Where I am relying on general knowledge of a reference's teaching rather than verified text, I flag it as such.

B. The claimed invention, distilled

Independent claims:

• Claim 1 (apparatus): (a) a tongue retractor comprising a cross-over plate, a first tongue shield plate, and an opposed second tongue shield plate; (b) a tongue retainer secured to the cross-over plate with first and second retainer arms that "flare outwardly and away from each other"; (c) at least one saliva ejector secured to the tongue retractor; and (d) a cheek-and-lip retractor connected to both retainer arms.
• Claim 13 (apparatus): same, but with first and second arms secured to the tongue retainer rather than arms formed integrally as retainer arms.
• Claim 21 (process): expanding cheeks/lips with a cheek-lip retractor; retracting the tongue with a tongue retractor that is supported by the floor of the mouth and formed of a cross-over plate with pivotally secured shield plates bordering the tongue; retaining the tongue with a retainer mounted atop the cross-over plate; and removing saliva "along a structural position" of the tongue retractor.
• Claim 23 (apparatus, narrowed): claim 1 minus the cheek/lip retractor element.

The specification's stated advance is a device that (1) isolates/dries the entire arch at once (not merely a quadrant), (2) retracts tongue, cheeks, and lips, (3) never crosses over the occlusal/incisal surfaces of the teeth, (4) is self-supporting on the floor of the mouth, and (5) restrains the tongue without blocking the vertical tongue movement required for swallowing.

C. What the two cited references teach

1. US 3,049,806 — Cofresi, "Multiple saliva ejector" (1962).
By its title and classification (saliva removers / aspiration), this teaches a saliva-evacuation appliance with multiple suction openings for removing saliva/fluids from several regions of the mouth simultaneously — i.e., multi-point evacuation rather than a single-tip ejector. This is the art the '298 patent's own Background distinguishes as devices that "dry and isolate no more than a quarter of the dental arch."

2. US 4,511,329 — Diamond, "Moisture controlling lingual dental mirror" (1985).
A companion design patent (D281,622, same inventor, "Combined dental mirror and moisture control apparatus") confirms the concept: an instrument used on the lingual (tongue) side that integrates a moisture/saliva-control (suction) function with a structure that holds soft tissue — the tongue — away from the field of work. Diamond therefore teaches the conceptual marriage of lingual tongue management with continuous moisture evacuation, which is the same problem/solution pairing at the heart of the '298 claims.

What neither reference discloses, on its face: a V-shaped tongue shield formed of a cross-over plate plus two opposed, pivotally adjustable shield plates; a separate tongue-retainer having arms flaring outward away from each other; or the mechanical linkage of the cheek/lip retractors to the tongue-retainer arms so that the whole assembly is self-supporting on the floor of the mouth with nothing crossing the teeth.

D. Claim mapping and obviousness combinations

Combination 1 — Cofresi '806 + Diamond '329 (the two examiner-cited references)

A PHOSITA (dental-instrument designer, circa 1985) who wants whole-arch isolation would have a textbook motivation to combine:

• Cofresi provides the reason to place multiple evacuation points around the arch rather than one; and
• Diamond provides the reason to put suction structure on the lingual side where the tongue is the moisture/soft-tissue problem, i.e., to combine tongue retraction with moisture control in one instrument.

That combination plausibly reads onto process claim 21 in broad form: expanding the cheeks/lips (well-known cheek retractors), retracting the tongue with a device resting on the floor of the mouth, holding the tongue with a retainer, and evacuating saliva along the retractor structure. Claim 21's steps are functional and general, and its "supported by the base of the oral cavity" and "removing saliva along a structural position" limitations map onto known floor-of-mouth saliva collection and ejector-tube geometry. Claim 21 is the most vulnerable claim.

The combination is weaker against the apparatus claims (1, 13, 23). The examiner evidently agreed — both references were before the examiner, and the claims issued. Neither Cofresi nor Diamond plausibly discloses: the specific V-shaped geometry with a cross-over plate joining two opposed shield plates; the separate tongue retainer with outwardly flaring arms; or the direct structural connection of the cheek/lip retractor to those retainer arms. Those are not mere design choices — they are what make the device self-supporting and what let the cheek/lip retraction and tongue retraction work as one assembly. A hindsight-driven combination of '806 and '329 would still lack several structural limitations of claims 1, 13, and 23.

Combination 2 — adding the background "cheek/lip retractor + saliva collector" art

The '298 specification's own Background describes (and thereby admits as art): (i) suction tubes with tissue shields that "pass over the teeth," isolating only a quarter of the arch; and (ii) perforated U-shaped metal tubes that wrap the arch on both buccal and lingual sides with a metal plate "which holds the tongue down." A PHOSITA aware of this art would naturally combine it with Cofresi's and Diamond's teachings:

• Take the known check/lip retractors (a mature art by 1985 — e.g., the Cohen device found in my search, US 3,027,643, "Combination … cheek and lip retractor and vacuum saliva ejector" (1962), which already married cheek/lip retraction with vacuum saliva evacuation);
• add the known lingual tongue guards/depressors with suction (Diamond; also the perforated-tube "tongue down" devices the patent admits);
• and arrive at a device that retracts cheeks/lips and evacuates saliva at the lingual floor-of-mouth.

This combination would render obvious the overall functional result the '298 patent claims — but again, the specific structure of claim 1 (cross-over plate + two pivotable shield plates; tongue retainer arms flaring outward; cheek retractors connected through those arms) is not the inevitable or obvious route to that result. Prior-art cheek retractors were connected to each other (e.g., via a spring bow, as the '298's own flexible member 56 shows), not tied through a tongue-retainer mounted on a cross-over plate. Nothing in the cited art teaches or suggests that load-path, which is the inventive departure.

Combination 3 — Cofresi/Diamond + known tongue retainers / mouth props

A PHOSITA motivated to keep the tongue down during whole-arch work could add a known tongue retainer or mouth prop (e.g., US 4,053,984, "Mouth prop," 1977; the "tongue down" plate art admitted in the Background). Adding a tongue-holding arm to a saliva-ejector frame was obvious in the abstract. But the specific "M-shaped"/"Y-shaped" retainer with arms flaring outwardly and away from each other, to which the cheek/lip retractors are attached, performs a dual function (tongue retention and structural bridge to the cheek retractors). Dual-function structural redesign is where the cited art is silent, and where a § 103 case for claims 1 and 13 is weakest.

E. Motivation-to-combine reasoning (why a PHOSITA would combine)

The dental-procedures context supplies strong, articulable motivations:

1. Known problem, known solution modules. The Background admits the long-felt need: crown/bridge, fluoride, sealant, and indirect-bonding procedures demand a dry, unobstructed entire arch. Cofresi (multiple suction), Diamond (lingual moisture control), and the cheek/lip-retractor art were each directed to pieces of that problem. Combining them addresses a recognized need — the classic § 103 motivation of "known technique, known problem, obvious to try."

2. No crossing the teeth. Because the Background criticizes prior devices that "pass over the teeth," a PHOSITA had an express reason to redesign the saliva-ejector frame to lie at the floor of the mouth and behind the last molars — the exact placement the '298 claims — which motivates mounting the suction at the lingual/buccal sulcus and supporting the frame on the floor of the mouth.

3. Swallowing constraint. The patent itself emphasizes the desirability of restraining the tongue "without hindering the act of swallowing." Prior "tongue-down" plates (admitted art) were rigid and blocked tongue lift; a PHOSITA would be motivated to substitute a tongue retainer that rests on the tongue yet permits vertical movement — i.e., the kind of open, non-encircling retainer the claims describe.

4. Predictable combination of known elements. Cheek/lip retractors, tongue shields, saliva conduits, and spring separators were all individually known; the claim elements are conventional components combined in a predictable way to produce a predictable result (full-arch exposure + continuous suction). Under KSR Int'l Co. v. Teleflex, Inc. (2007), this weighs toward obviousness even absent a specific teaching-to-combine, because a PHOSITA would combine known prior-art elements "according to known methods with no change in their respective functions."

F. Bottom line

• Most vulnerable: Claim 21 (process) — it is drawn at a functional level of generality that maps readily onto the combined teachings of Cofresi '806 (multi-point saliva removal), Diamond '329 (lingual moisture control/tongue retraction), and the admitted background art (cheek/lip retraction, floor-of-mouth support). A combination of Cofresi + Diamond, or either + the conventional cheek-retractor/saliva-ejector art, presents a strong § 103 case.
• Moderately vulnerable: Claim 23 (apparatus without the cheek/lip retractor) — if a prior-art saliva-ejector frame with a tongue-holding retainer existed (or if Diamond's lingual instrument is construed broadly), the added retainer-arm limitation may be obvious.
• Least vulnerable (and evidently how the claims survived examination): Claims 1 and 13 — the specific combination of (i) the V-shaped cross-over-plate/shield-plate geometry with pivotally adjustable opposed shield plates, (ii) the separately secured tongue retainer with outwardly flaring arms, and (iii) the cheek/lip retractors connected to those retainer arms so that retraction and retention are structurally integrated and self-supporting, is not disclosed or suggested by Cofresi '806, Diamond '329, or the admitted background art. No cited reference teaches the tongue-retainer-to-cheek-retractor load path, which is the core structural departure. An obviousness rejection over the two cited references would likely fail for lack of disclosure of, and motivation to arrive at, that integrated structure.

Net assessment: The strongest § 103 attack combines Cofresi '806 (multi-point suction) with Diamond '329 (lingual moisture control) — plus conventional cheek/lip retractors and mouth props known before 1985 — to knock out process claim 21 and potentially claim 23, but claims 1 and 13 would likely withstand that combination because the record contains no prior-art suggestion of the V-shaped pivotal tongue shield integrated with an outward-flaring retainer that structurally carries the cheek/lip retractors. I could not verify the full disclosures of the two cited patents from live sources, so this conclusion should be re-checked against the actual '806 and '329 specifications before it is relied upon in an office action or litigation context.