US 5460524

Summary: US Patent 5,460,524 (US5460524A)

Search note

I searched for the specific patent number 5460524 (and its printed form 5,460,524) across USPTO-adjacent sources (Google Patents, Justia, FreePatentsOnline, and the USPTO PDF image copy). No CAFC 2026 docket entries referencing this patent were found — my searches for CAFC 2026 appeals citing this patent number returned no results. This is consistent with the patent's legal status: it lapsed in 2003 for failure to pay maintenance fees and is expired. I have no authoritative information indicating any 2026 CAFC or USPTO proceeding involving this patent, and I did not locate a USPTO Patent Center docket for it.

Bibliographic data

Abstract (paraphrased from the patent)

A dental device for removing saliva and retracting the tongue comprising a retraction unit (22) having a tongue shield (28). A bite handle (30) is connected to the tongue shield (28) to stabilize the unit (22), and is held between the biting teeth. At least one tube holder (36) is secured to the tongue shield (28) adjacent to a rearmost molar tooth, and a suction tube (24) is attached to each tube holder (36). A Y-tube adapter (26) may be used to connect two suction tubes (24) with a single conventional fitting of the operatory suction system. A method for removing saliva and retracting the tongue within an oral cavity includes retraction with a tongue shield (28), stabilizing the tongue shield (28) with a bite handle (30), and removing saliva along a tube holder (36) secured to the tongue shield (28) adjacent to a rearmolar molar tooth.

Independent claims — plain-language overview

The patent has 20 claims. The independent claims are claims 1, 5, and 7 (claims 2–4 depend from claim 1; claim 6 depends from claim 5; claims 8–20 depend from claim 7).

Claim 1 (apparatus). A saliva-removal dental device that retracts both tongue and cheek, having:

• a generally U-shaped tongue shield (with internal surface, external surface, and first and second rear ends) forming a wall between the tongue and the teeth to hold the tongue back;
• a bite handle attached to the shield's external surface forward of the first rear end, projecting outward so it can be clenched between the teeth, stabilizing the shield;
• a tube holder secured near the first rear end, extending outward so it sits behind the rearmost molar when in place;
• a suction tube (anterior end, posterior end, tube wall) whose posterior end attaches to the tube holder, drawing saliva from the holder region and also retracting the cheek; and
• at least one reinforcement (e.g., a wire) carried within the tube wall giving the tube enough stiffness to hold the cheek away.

Claim 5 (method). A method of saliva removal and tongue/cheek retraction away from the molars, comprising:

• (a) retracting the tongue with a generally U-shaped tongue shield;
• (b) stabilizing the shield with a bite handle (attached forward of the first rear end) held between the teeth;
• (c) removing saliva via a suction tube positioned at a tube holder secured near the first rear end, behind the rearmost molar; and
• (d) retracting the cheek with the suction tube, whose wall carries a reinforcement giving the tube enough sturdiness to retract the cheek.

Claim 7 (apparatus, broader functional combination). A dental device for saliva removal, for increasing tooth access by propping the teeth open, and for retracting the tongue and cheek, comprising:

• (a) a retraction unit having (i) the U-shaped tongue shield with internal/external surfaces and first/second rear ends, (ii) a bite handle forward of the first rear end that projects outward and is engaged by the teeth — serving both to stabilize the shield and to prop the teeth open, and (iii) at least one tube holder near the first rear end, projecting outward and sitting behind the rearmost molar;
• (b) a suction tube (with tube wall) connected to the tube holder for saliva removal and cheek retraction; and
• (c) a reinforcement inside the tube wall giving the tube sufficient sturdiness to retract the cheek.

Notable dependent-claim features (claims 2–4, 6, 8–20)

• A bilateral/full-arch version with a second tube holder, second suction tube, and a Y-tube adapter joining both tubes to a single operatory fitting (claim 2), optionally with concentric high-volume and low-volume attachments for compatibility with both standard fitting sizes (claim 3).
• A stabilizing shelf on the shield's internal surface (claim 4); a method step of propping the teeth open with the bite handle (claim 6).
• Removable/reattachable bite handle (claim 8); detachable tongue-shield subunits for packaging (claim 9); a separate cheek-retractor means (claim 10); reinforcement as a ductile wire (claim 11); plastic construction (claim 12); internal (claim 13) or external (claim 14) tube-holder attachment; notched bite handle (claim 15); asymmetric (claim 16) or symmetric (claim 17) shield; anterior vs. posterior bite engagement (claims 18–19); and an extension arm for lateral tube positioning (claim 20).

Uncertainty disclosure

The bibliographic data above is corroborated by the Google Patents record (fetched 2026-09-06), Justia, FreePatentsOnline, and the USPTO PDF at patentimages.storage.googleapis.com/90/ff/25/1510989f87512c/US5460524.pdf. I did not directly query the USPTO Patent Center or the CAFC docket database in this session; my "no CAFC 2026 docket" conclusion is based solely on web searches returning no results and on the patent's expired status, so I cannot rule out the existence of an unindexed or non-public proceeding with complete certainty.

I'll search for litigation involving US Patent 5,460,524 across available sources.

The initial results reference different patents (e.g., a tire-pressure '524 patent and others) — not the dental-device patent at issue. I'll search more precisely.

I've confirmed the patent identity (Ross W. Anderson's dental saliva-suction/tongue-retractor device). Now let me check litigation-specific databases directly.

Based on my searches of the available sources, I have no evidence of any litigation involving US Patent 5,460,524 (the Ross W. Anderson dental device for saliva suction with tongue retractor and bite handle).

Findings

No known litigation identified. I searched for the specific patent number and related identifiers ("5,460,524", "US5460524", "5460524") and found no district-court complaints, IPR/PGR proceedings, CAFC appeals, or PTAB actions naming this patent.

Important — results for similar numbers are unrelated. Several search hits referenced a "'524 patent," but those were different patents and must not be conflated:

• US 5,602,524 — a tire-pressure monitoring patent involved in Wasica Finance GmbH v. Continental Automotive Systems, Inc. (IPR2014-00295, IPR2014-00476, CAFC appeal decided April 4, 2017). Not the dental patent.
• Various other "'524" patents (e.g., a Nuance transcription patent, a Dialight LED patent) also surfaced, none of which is US 5,460,524.

Context supporting the absence of litigation. The patent's USPTO legal-event history (as shown on the Google Patents record) indicates:

• Filed June 24, 1994; granted October 24, 1995;
• Maintenance fee paid in 1998 (year 4);
• Lapsed October 24, 2003 for failure to pay maintenance fees ("LAPS – Lapse for failure to pay maintenance fees"; "PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362"); status: Expired – Fee Related.

The patent expired roughly two decades ago, which is consistent with the absence of any reported litigation.

Caveat

My search coverage was limited to general web/litigation-index searches (including Unified Patents-style sources attempted). I did not exhaustively search every PACER jurisdiction or paywalled docket services (Docket Navigator, RPX, Lexis/ Westlaw litigation tabs). If you need a definitive clearance statement, I recommend a formal docket search (PACER) across all district courts plus the PTAB and CAFC dockets for the exact patent number "5,460,524."

Bottom line: Based on the available information, there is no known litigation involving US Patent 5,460,524 as of the current date.

The initial searches returned no relevant hits — one empty result, one unrelated pharma IPR (IPR2025-00464 on patent 8,895,546). Let me verify further against USPTO and CAFC sources.

Proceedings overview

Total AIA trial proceedings (IPR/PGR/CBM): 0 — zero active, zero with claims invalidated, zero with claims sustained, zero settled, zero institution-denied. The USPTO Open Data Portal (canonical structured data) returns no AIA trial proceedings for US 5,460,524 as of the most recent ingest, and independent web searches confirmed no PTAB docket, PTAB decision, or Federal Circuit appeal referencing this patent. Defensive posture bottom line: this patent has never been through a single AIA trial — but it has been expired since 2003, so no proceeding was ever needed; the patent is unenforceable for any post-expiration conduct, and an IPR-based attack is unnecessary (and untimely) when expiration alone is a complete defense.

Proceedings

No proceedings to report. There are no IPR, PGR, or CBM cases against US 5,460,524.

Per the operating rules, I will not fabricate proceeding numbers, judge panels, grounds, or decisions. The structured USPTO ODP data block included in this prompt — which is the canonical list — contains no AIA trial proceedings. Web searches for "5,460,524" inter partes review, "US5460524" IPR, and site-restricted USPTO/PTAB queries all returned either empty results or unrelated matters (e.g., IPR2025-00464 concerns patent 8,895,546; a Japanese patent numbered 5460524 is an unrelated digital-receiver patent; a Supreme Court cert petition in Tehrani references an "Anderson" prior-art paper in a ventilation case — not this dental patent).

That absence is not a coincidence; it is structural:

• The patent expired before AIA trials existed. US 5,460,524 lapsed 2003-10-24 for failure to pay maintenance fees (USPTO legal events: "LAPS – Lapse for failure to pay maintenance fees"; "PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362"). AIA review proceedings (IPR/PGR/CBM) only became available on 2012-09-16 — nine years after this patent was already dead.
• An IPR petition on an expired patent is only viable where a petitioner faces an actual infringement controversy (e.g., a pending suit seeking pre-expiration damages). The separate litigation review found no district-court actions naming this patent, so no such controversy ever materialized.

Strategic summary

Claim status: all 20 claims (1–20) are UNTESTED in any AIA trial — and equally, all are unenforceable. No PTAB panel has ever canceled, sustained, or construed a single claim of US 5,460,524. The claims are also unenforceable in district court as a matter of law for any act after the patent lapsed in 2003. The only theoretical exposure would be pre-2003 damages in a long-since-barred suit — the statute of limitations and laches foreclose any realistic assertion today.

Estoppel landscape (§ 315(e)(2)): irrelevant, but note the asymmetry. No petitioner exists, so no § 315(e)(2) estoppel has attached to anyone. That said, a defendant does not need a § 102/§ 103 defense at all: the patent's expiration is a complete, non-invalidity defense to infringement (35 U.S.C. § 271 ends at expiration; no remedy lies for post-expiration practice). If a would-be plaintiff is threatening suit over an expired patent, the correct response is not an IPR — it's a declaratory-judgment action or a motion to dismiss asserting no post-expiration liability, plus a hard look at Rule 11 / fee-shifting exposure for the demand letter.

Pattern signals: none. No petitioner has filed multiple IPRs; no defensive aggregator (e.g., Unified Patents) appears in any chain; the patent owner (individual inventor Ross W. Anderson) never pursued PTAB proceedings because there were none to defend. Notably, the inventor's later family of dental dry-field patents (e.g., US 7,785,105, and the related applications US 2004/0101804, US 2005/0074720, US 2007/0148619) cites US 5,460,524 as its own prior art — the inventor built on, rather than enforced, this patent.

Recommended next steps

1. Do not file an IPR. The statutory bar and the complete expiration defense make a PTAB petition wasted spend. The USPTO ODP confirms zero proceedings; there is no FWD to cite and no claim-narrowing to exploit.
2. If you are a defendant facing a demand letter or suit citing US 5,460,524: respond that the patent expired 2003-10-24 (USPTO legal-event record: LAPS/FP — lapsed for nonpayment of maintenance fees; status "Expired – Fee Related"). No cause of action can reach your current or past-recent conduct. If suit is filed, move to dismiss under Fed. R. Civ. P. 12(b)(6) on the ground that the patent is expired, and consider seeking fees under 35 U.S.C. § 285 if the assertion is objectively baseless.
3. Watch for the real risk — a different, live patent. Anderson and related entities hold later, unexpired dental dry-field patents (e.g., US 7,785,105, issued 2010-08-31 and still within its term, plus continuation family members listed in the "Cited By" record such as US 2004/0101804 A1, US 2005/0074720 A1, US 2007/0148619 A1, and Dryshield/Solmetex family members like US 9,788,924 and US 11,589,970). If a demand letter cites US 5,460,524, it may be a decoy or a mistaken cite — check whether the asserted product is actually accused under one of the later, live Anderson-family patents, and run a fresh PTAB ODP and PACER search on those numbers if so.
4. If you want a definitive clearance record: the absence of PTAB activity is already documented via the ODP ingest cited here; for completeness, a formal PACER search across all district courts for the exact patent number "5,460,524" plus assignee "Anderson" will memorialize the no-litigation position. Expect it to confirm what the maintenance-fee lapse already tells you: this patent has been commercially dead for over two decades.

Based on the searches available in this session (which did not include a direct, successful query of the USPTO Assignment Center live database — I was rate-limited before I could load reel/frame results), the following reconstruction is built from Google Patents legal-event data, patent-front-page data, and the inventor's later patent family. Where I could not verify a record directly, I say so rather than fabricate reel/frame entries.

Inventors

• Ross W. Anderson — sole named inventor. His employer at the time of filing (June 24, 1994) is not determinable from the patent record; the patent issued with no corporate assignee. Later filings by the same person (Ross William Anderson, of 6287 Mercedes La., Plymouth, MI 48170, per the front page of USD564658) were made in his own name as an individual, which is consistent with an independent dentist/clinical inventor rather than an employee-inventor of a corporate assignee. No "all inventors departed the assignee" pattern is present — there was no corporate assignee to depart.

Original assignee

• None (individual ownership). Google Patents lists the "Original Assignee" as Individual, and the patent's front page shows no corporate assignee (no (73) entity). There is no evidence that any company shipped a product embodying the claims during the patent's life; the inventor continued developing the concept personally, filing related applications (US 2004/0101804, US 2005/0074720, US 2007/0148619, and US 7,785,105 B2, all titled "Apparatus for Maintaining a Dry Field During Dental Procedures") in his own name through the 2000s. The patent lapsed October 24, 2003 for failure to pay maintenance fees (USPTO legal-event codes: LAPS; "PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362"); status is Expired – Fee Related. The original owner's chain therefore ended by simple expiration, not by sale or bankruptcy.

Assignment timeline

• No recorded assignments located. Searches for the patent number, the application number (08/264,903), and the inventor's name surfaced no recorded conveyances — no execution dates, recording dates, or reel/frame numbers are available to report. Google Patents' legal-event history for US 5,460,524 shows only prosecution/maintenance events (filing 1994-06-24; grant 1995-10-24; maintenance fee paid 1998; lapse 2003-10-24) and no assignment events. Because the patent issued to the inventor as an individual and his later continuation family remained in his own name, the absence of recorded assignments is consistent with the original owner (the individual inventor) holding the patent until expiry.

Caveat: I could not complete a direct query of assignmentcenter.uspto.gov / assignment.uspto.gov within this session's step limit. If a definitive clearance statement is required, verify by searching the USPTO Assignment Center by patent number 5460524 (verification link: https://assignmentcenter.uspto.gov/). Based on all secondary evidence, I expect that search to return no records.

Timeline diagram

timeline
    title Ownership of US 5460524
    1994 : Filed by Ross W Anderson as individual
    1995 : Patent issued to inventor
    1998 : Maintenance fee paid year four
    2003 : Patent lapsed fee not paid
    2003 : Expired fee related status

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No transfer to any LLC, "IP Holdings," licensing entity, or registered-agent address exists in any record located. The patent never left the individual inventor.
2. Known asserter in the chain — not present. No Acacia, Marathon, IV, Wi-LAN, Conversant, or any Unified Patents/RPX-listed entity appears anywhere in the chain (there is no chain to appear in).
3. Repeat correspondent across the chain — not present. With zero recorded conveyances, there is no correspondent of record on any assignment to analyze.
4. Cascading transfers — not present. No consecutive chained assignments exist.
5. Pre-litigation transfer — not present. The prior litigation analysis found no infringement suits naming this patent, and there are no assignments of any kind, let alone transfers timed within six months of a complaint.
6. Bankruptcy fire-sale — not present. The owner was an individual; the patent expired by non-payment of maintenance fees, not through any bankruptcy proceeding.
7. Privateering — not present. No operating company transferred rights to an NPE; there is no evidence of any SEC disclosure or EFF/Patent Progress coverage to that effect.
8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. It terminates at expiration.

Additional affirmative signal against NPE activity: the owner allowed the patent to lapse in 2003 for non-payment of maintenance fees (USPTO legal events, LAPS dated 2003-10-24). An expired, unmaintained patent has no assertion value, which is strongly inconsistent with any NPE acquisition or monetization intent.

Verdict

Insufficient data (no recorded assignments located; the patent issued to the inventor as an individual and expired in 2003).

The absence of any recorded assignment, combined with the inventor-owned continuation family and the patent's lapse for unpaid maintenance fees in 2003, points to a straightforward individual-inventor history with no NPE involvement — but because I could not complete a live USPTO Assignment Center query this session (rate-limited), I cannot certify the assignment record with the reel/frame specificity this analysis normally requires. Verify at https://assignmentcenter.uspto.gov/ (search patent number 5460524) to confirm the expected empty result.

I'll research the cited prior art references for US 5,460,524. Let me start by verifying the patent itself and searching for each cited reference.

Now let me search for the remaining cited references.

I've reached the tool-call limit for this session, so I'll complete the analysis from the verified Google Patents/USPTO record for US 5,460,524 (provided in the task), the patent's own specification, and the search snippets already retrieved. Where I could not independently verify a reference's full text this session, I flag that explicitly.

US 5,460,524 — Prior Art Analysis of the Examiner's Cited References

1. Patent identity and governing law

• Patent: US 5,460,524 A — "Device and method for saliva suction with tongue retractor and bit handle"
• Inventor: Ross W. Anderson (Individual)
• Application: US 08/264,903, filed June 24, 1994; granted October 24, 1995
• Status: Expired — Fee Related (lapsed October 24, 2003 for non-payment of maintenance fees)
• Governing statute: Because the application was filed before March 16, 2013, pre-AIA 35 U.S.C. § 102 applies.
• § 102(b) critical date: More than one year before June 24, 1994 = June 24, 1993. Every one of the eight U.S. patents cited by the examiner issued between 1962 and 1992, i.e., before June 24, 1993. Accordingly, each is prior art under at least pre-AIA § 102(b) (and presumptively § 102(a)). The single non-patent citation ("Denta Pops," May 1993) also predates the critical date.

2. Claim structure of US 5,460,524 (for mapping)

• Independent claims: 1 (device), 5 (method), 7 (device).
• Dependent claims: 2–4 → claim 1; 6 → claim 5; 8–20 → claim 7.
• Limitation clusters that matter for § 102 single-reference analysis:
  1. Generally U-shaped tongue shield (internal/external surfaces; first and second rear ends) forming a wall between tongue and teeth;
  2. Bite handle connected to the external surface of the shield, forward of the first rear end, projecting outward, engaged between the teeth to stabilize the shield (claims 1, 5, 7) and to prop open the teeth (claims 6, 7);
  3. Tube holder secured adjacent to the first rear end, located rearward of the rearmost molar when in place;
  4. Suction tube attached to the holder, removing saliva "along a structural position of said tube holder," and retracting the cheek;
  5. Reinforcement carried within the tube wall of the suction tube giving it sufficient stiffness to retract the cheek (claims 1, 5, 7; "ductile wire" per claim 11).

3. The eight cited U.S. patents (all "cited by examiner" on the record)

3.1 US 3,049,806 A — Cofresi, "Multiple Saliva Ejector"

• Full citation: Cofresi, Rafael, U.S. Patent No. 3,049,806, filed October 9, 1959, issued August 21, 1962, "Multiple Saliva Ejector."
• Description: Tubular saliva ejector with inlet orifices positioned on both sides of a set of teeth, plus an adjustable brace serving as a tongue depressor. Disclosed in the '524 specification as prior art lacking a mechanism for propping open the biting teeth.
• § 102 analysis: Discloses a U-shaped/arch-spanning suction tubular member with orifices on both sides of the teeth and tongue-depressing structure. It does not disclose a bite handle connected to the external surface of a tongue shield and engaged between the teeth for stabilization, a tube holder positioned rearward of the rearmost molar, or a reinforced suction tube performing cheek retraction. Potential anticipation: None of the independent claims (1, 5, or 7) as a single reference — it lacks the bite-handle, rearward tube-holder, and in-wall reinforcement limitations. Best characterized as an element-level reference (dual-side suction orifices; tongue depressing) relevant to claims 1, 5, and 7 sub-combinations under § 103, not § 102.

3.2 US 4,215,984 A — Reichley, "Dental Suction Device"

• Full citation: Reichley, Joseph P., U.S. Patent No. 4,215,984, filed January 15, 1979, issued August 5, 1980, "Dental Suction Device."
• Description: A U-shaped metal tubular suction base with evacuation slots/holes sized to fit inside the lower teeth; an upstanding tubular member carrying an elliptically shaped tongue-depressor plate; and a tubular stem with an adjustable tooth rest (optionally a rubber bite ball) engaged by the upper incisal teeth to hold the patient's mouth open.
• § 102 analysis: This is the closest of the older references to the "engage-between-the-teeth to prop the mouth open" concept (adjustable tooth rest) plus tongue depressing and full-arch U-shaped suction. However, the tooth rest is mounted on a stem/collar rather than being a bite handle connected to the external surface of a U-shaped tongue shield forward of its rear end; there is no separate tube holder positioned rearward of the rearmost molar; and the suction base is rigid metal tubing rather than a plastic suction tube with in-wall reinforcement retracting the cheek. Potential anticipation: Not claim 1, 5, or 7 in full. Relevant to the bite-engagement/propping function (claims 6 and 7's propping limitation) and to U-shaped full-arch saliva removal (claims 1, 5, 7), but under § 103 rather than § 102.

3.3 US 4,259,067 A — Nelson, "Combined Saliva Ejector, Tongue Retractor and Throat Protector"

• Full citation: Nelson, David P., U.S. Patent No. 4,259,067, filed October 25, 1977, issued March 31, 1981, "Combined Saliva Ejector, Tongue Retractor and Throat Protector."
• Description: Disposable foam-elastomeric dental shield placed vertically between the teeth and tongue. A wire frame with palatal and lingual members is resiliently biased apart to compressively engage the roof and floor of the mouth; the lingual member includes a C-shaped saliva-collecting tube (with the wire frame disposed within the tube) having apertures along the lingual edge; a throat-protector extends rearward.
• § 102 analysis: Notably, Nelson places a wire within the saliva tube (resembling the '524 in-wall reinforcement) and combines tongue retraction with saliva ejection from a shield-mounted tube. But Nelson's stabilization mechanism is compressive engagement between palate and mouth floor — not a bite handle engaged between the teeth — and its tube is affixed along the lingual edge rather than to a discrete tube holder rearward of the rearmost molar. The '524 specification itself criticizes Nelson as "numerous complicated parts." Potential anticipation: Does not anticipate claims 1, 5, or 7 in full. Most relevant to the shield+integrated suction tube+in-tube wire combination (claims 1, 5, 7) under § 103; potentially an element reference for claim 4 (stabilizing shelf equivalents) only cumulatively.

3.4 US 4,260,378 A — O'Neil, "Self Stabilizing Intra-Oral Saliva Evacuator"

• Full citation: O'Neil, Robert J., U.S. Patent No. 4,260,378, filed June 1, 1979, issued April 7, 1981, "Self Stabilizing Intra-Oral Saliva Evacuator." (The Google Patents record abbreviates the inventor as "Neil Robert J O"; the patent itself is O'Neil.)
• Description: Self-stabilizing evacuator with a resilient metallic main frame of U-shaped lingual and buccal loops held in spaced relation by bridging members that rest astride the maxillary and mandibular teeth, holding the arches widely open; flexible perforated tubing is telescoped over the loops and connected to a source of evacuation; a lingual guard prevents tongue contact with the molars; a pair of devices can evacuate both sides.
• § 102 analysis: Discloses tongue isolation (lingual guard), saliva evacuation adjacent to the molars on both lingual and buccal sides, and teeth-borne stabilization that props the mouth open. However, the stabilizing structure is arch-straddling bridging members, not a bite handle projecting forward from the external surface of a U-shaped tongue shield; the suction is via tubing over the wire loops, not a suction tube attached to a tube holder rearward of the rearmost molar and used to retract the cheek; and the "reinforcement" is a structural metal frame rather than reinforcement carried within the wall of a suction tube that itself retracts the cheek. Potential anticipation: Not claims 1, 5, or 7 in full. Relevant under § 103 to the full-arch, mouth-propping, bilateral suction concepts (claims 1, 2, 5–7).

3.5 US 4,511,329 A — Diamond, "Moisture Controlling Lingual Dental Mirror"

• Full citation: Diamond, Michael K., U.S. Patent No. 4,511,329, filed January 26, 1984, issued April 16, 1985, "Moisture Controlling Lingual Dental Mirror."
• Description: Hand-held dental mirror instrument for viewing the lingual (inside) tooth surfaces, providing saliva suction, and serving as a tongue retractor; incorporates a bite block. The '524 specification criticizes it as having "a bite block which directly obstructs access to the molars."
• § 102 analysis: A clinician-manipulated mirror instrument, not a self-supporting full-arch retraction unit. It lacks the U-shaped tongue shield with an anterior bite handle on its external surface, the rearward-of-the-molar tube holder, and a reinforced suction tube that retracts the cheek. Potential anticipation: None of claims 1, 5, or 7. Marginal § 103 relevance only (tongue retraction + suction in one instrument).

3.6 US 4,975,057 A — Dyfvermark, "Dental Appliance"

• Full citation: Dyfvermark, Ulf T., U.S. Patent No. 4,975,057, filed February 19, 1988, issued December 4, 1990, "Dental Appliance."
• Description: A bite-block appliance with an aperture serving as an evacuation nozzle for saliva suction. The '524 specification criticizes it as isolating only one-half of the dental arch, having a bite block that obstructs access to the molars, and lacking cheek retraction from the rearmost molar area.
• § 102 analysis: Lacks the U-shaped tongue shield, the forward external bite handle, the rearward tube holder, the cheek-retracting function of the suction tube, and the in-wall reinforcement. Potential anticipation: None of the independent claims. Minimal § 103 relevance (bite block with integrated evacuation nozzle — a feature the '524 claims avoid, not adopt).

3.7 US 5,037,298 A — Hickham, "Apparatus and Improved Process for Removing Saliva While Retracting Cheeks and Lips"

• Full citation: Hickham, John J., U.S. Patent No. 5,037,298, filed November 25, 1985, issued August 6, 1991, "Apparatus and Improved Process for Removing Saliva While Retracting Cheeks and Lips."
• Description: Apparatus for ejecting saliva with a pair of saliva ejectors connected to a tongue retractor and a cheek/lip retractor connected to a tongue retainer secured to the tongue retractor. The '524 specification criticizes it as having numerous complicated parts and no method for propping open the biting teeth.
• § 102 analysis: This reference is the most factually similar to the '524's functional goals (tongue retraction + cheek retraction + saliva ejection simultaneously), but it achieves cheek retraction with a separate cheek-retractor component attached to a tongue retainer — not by a reinforced suction tube whose wall carries a stiffening element and which itself retracts the cheek. It also lacks a bite handle engaged between the teeth for stabilization/propping. Potential anticipation: Not claims 1, 5, or 7 in full, because the cheek-retraction mechanism and the bite-handle limitation are structurally different. Highly relevant § 103 reference against claims 1, 5, 7, and dependent claim 10 (cheek-retractor means); possible § 102 candidate only if the cheek retractor were argued to be equivalent to the reinforced tube, which the claim language does not permit.

3.8 US 5,152,686 A — Duggan, "Dental Appliance"

• Full citation: Duggan, Calvin, U.S. Patent No. 5,152,686, filed April 25, 1991, issued October 6, 1992, "Dental Appliance."
• Description: Appliance for suctioning debris from the oral cavity with a tongue stabilizer and a removable suction tube secured to a bite block. The '524 specification criticizes it as isolating only one-half of the arch, having a bite block obstructing molar access, and lacking cheek retraction from the rearmost molar areas.
• § 102 analysis: Although it has a bite block the patient bites on and a tongue stabilizer, the bite block is positioned posteriorly over the molars (obstructing them) rather than being a bite handle projecting forward from the external surface of a U-shaped tongue shield; there is no rearward tube holder; and there is no reinforced suction tube retracting the cheek. Potential anticipation: None of claims 1, 5, or 7 in full. § 103 relevance only (bite-engaged stabilization + suction, and removable suction tube analogous to dependent claim features).

4. Non-patent citation on the record

• Citation: David Kanas, D.D.S., Denta Pops™ Dry Field Aspirator, Amera Dent Inc. of Nevada, May 1993 (listed twice in the record's Non-Patent Citations).
• Description: A commercial disposable dry-field aspirator product brochure/description (May 1993).
• § 102 analysis: Published May 1993 — before the June 24, 1993 critical date — so it qualifies as prior art under pre-AIA § 102(b). The '524's own file history does not describe its contents in the specification text available to me, and I could not retrieve the full product literature this session. If the Denta Pops device disclosed a bite-held, shield-type aspirator with integrated suction, it could be a strong § 102(b) candidate against claims 1, 5, and/or 7; this requires document-level verification before asserting.

5. Bottom line

• All eight U.S. patents are proper § 102(b) prior art (issued 1962–1992, all more than one year before the June 24, 1994 filing).
• No single cited reference appears to anticipate the full scope of independent claims 1, 5, or 7. Each lacks at least one structural requirement of the claimed combination — most commonly the (i) bite handle connected to the external surface of a U-shaped tongue shield forward of its rear end and engaged between the teeth, (ii) tube holder positioned rearward of the rearmost molar, and (iii) reinforcement within the suction tube wall enabling the tube itself to retract the cheek.
• The closest functional prior art is Hickham '298 (tongue + cheek retraction with saliva ejection) and Reichley '984 (bite-engaged mouth propping with full-arch suction); the closest structural prior art for the reinforced-tube feature is Nelson '067 (wire within the saliva tube).
• Accordingly, the cited references are best characterized as § 103 obviousness combinations (e.g., Reichley or O'Neil for bite-propping/arch-spanning structure + Hickham for cheek retraction + Nelson for in-tube wire reinforcement) rather than as standalone § 102 anticipating references. The examiner's citations appear to support rejections or a § 103-based close examination rather than a single-reference § 102 rejection.

Verification caveat: I fully verified the bibliographic data and the '524 specification/claims from the Google Patents/USPTO record. I retrieved substantive full-text for Reichley '984, Nelson '067, O'Neil '378, and partial content for Cofresi '806. I could not retrieve full texts this session for Diamond '329, Dyfvermark '057, Hickham '298, Duggan '686, or the Denta Pops brochure; their descriptions above rest on the '524 specification's own prior-art discussion (which is authoritative for what the applicant admitted) and my training knowledge. For a formal § 102/§ 103 opinion, each reference's figures and claims should be pulled from the USPTO Patent Center or Patent Public Search and checked element-by-element.

§ 103 Obviousness Analysis — US Patent 5,460,524 (Anderson, "Device and method for saliva suction with tongue retractor and bit handle")

Scope and evidentiary basis

This memorandum evaluates whether the claims of US 5,460,524 would have been obvious under 35 U.S.C. § 103 as of the June 24, 1994 filing date, using only the prior art listed in the "Prior Art" / citations section of the patent record (the eight U.S. patents cited by the examiner and the single non-patent literature item). Where I verified reference content by live search, I ground the analysis in that content; where I could not independently verify details (noted below for Reichley and Neil), I rely only on what the '524 specification itself states about those references and flag the limitation.

Prior-art set under consideration (examiner-cited):

1. US 3,049,806 — Cofresi, "Multiple Saliva Ejector" (1962)
2. US 4,259,067 — Nelson, "Combined Saliva Ejector, Tongue Retractor and Throat Protector" (1981)
3. US 4,215,984 — Reichley, "Dental Suction Device" (1980)
4. US 4,260,378 — Neil, "Self Stabilizing Intra-Oral Saliva Evacuator" (1981)
5. US 4,511,329 — Diamond, "Moisture Controlling Lingual Dental Mirror" (1985)
6. US 4,975,057 — Dyfvermark, "Dental Appliance" (1990)
7. US 5,037,298 — Hickham, "Apparatus and Improved Process for Removing Saliva While Retracting Cheeks and Lips" (1991)
8. US 5,152,686 — Duggan et al., "Dental Appliance" (1992)
9. NPL: David Kanas, D.D.S., "Denta Pops™ Dry Field Aspirator," Amera Dent Inc. of Nevada (May 1993)

I. Legal framework

Obviousness is assessed under the Graham factors: (1) scope and content of the prior art; (2) differences between the prior art and the claims; (3) level of ordinary skill in the art; and (4) objective indicia of non-obviousness. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), confirms that a combination of known elements is obvious when a PHOSITA would have had reason to combine them to achieve a predictable result — "the combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results." Motivation may be found in the nature of the problem, the teachings of the references, and the general knowledge of persons skilled in the art; there is no rigid teaching-suggestion-motivation requirement.

Level of ordinary skill (POSITA): A designer of dental suction/isolation devices — e.g., an individual with a dental degree or a B.S./equivalent in mechanical or biomedical engineering plus roughly 2–5 years of experience designing saliva ejectors, retractors, and isolation mouthpieces for operatory suction systems, familiar with the standard low-volume/high-volume (LV/HVE) operatory fittings, disposable-plastic product economics, and infection-control requirements. The field is crowded and incremental; the POSITA's skill level is moderate.

II. Closest prior art — and the differences the claims present

Hickham (5,037,298) is the closest single reference. Verified content (FreePatentsOnline/Justia) shows Hickham discloses:

• A tongue retractor formed of a cross-over plate and first and second tongue shield plates pivotally secured to it — i.e., a bilateral, arch-shaped shield system that, when opened and placed in the mouth, borders and retracts the tongue;
• Two saliva ejectors/conduits, one secured at each of the two tongue-retractor ends, expressly positioned "behind the last teeth of the lower teeth" (i.e., rearward of the rearmost molar — the same location claimed in '524);
• Saliva removal "along a structural position of said tongue retractor means" (Hickham claim 21(d)) — language nearly identical to '524 claim 1's "removing saliva from along a structural position of said tube holder";
• Cheek and lip retractors for expanding the cheeks away from the teeth;
• An explicit objective that "no part of the apparatus [crosses] over the tops of any teeth," preserving access to molar biting surfaces;
• A process claim (claim 21) covering tongue retraction, cheek/lip retraction, saliva removal along the retractor — substantially anticipating the method of '524 claim 5 minus the bite-handle stabilization and the in-tube-wall reinforcement.

Material differences between Hickham and the independent claims:

1. Bite handle (claims 1, 5, 7): Hickham stabilizes the device by resting the tongue retractor on the floor/base of the oral cavity, using a tongue retainer on top of the tongue and separate cheek retractors — no handle engaged between the biting teeth. Claim 1 requires a bite handle on the external surface of the shield, forward of a rear end, engaged between the teeth; claim 7 additionally requires that the handle prop the teeth open.
2. Reinforcement inside the suction-tube wall (claims 1, 5, 7): Hickham's suction conduits are separate from its cheek retractors. No reference in Hickham teaches a wire/ductile reinforcement carried within the tube wall that gives the tube itself enough stiffness to retract the cheek.
3. Y-tube adapter and dual-tube architecture (claim 2) is not expressly in Hickham (which shows two hoses to a suction source without a single Y-connector fitting).

Those gaps are precisely the kind of known, modular elements a POSITA would have supplied from the other cited references.

III. Proposed combinations and motivation to combine

A. Claim 1 (apparatus) — Hickham + Duggan + Nelson (+ conventional wire-reinforced ejector tube)

Motivation to combine: All references address the same recognized problem — maintaining a clear, dry, full-arch operating field without obstructing the molars (Hickham's background describes the identical unmet need; '524's background repeats it). A POSITA reading Hickham would immediately see that its elaborate support system (pivot hinges, tongue retainer, spring-loaded cheek retractors, base-of-mouth resting) is complicated — the very deficiency '524 concedes in the prior art. Duggan teaches a far simpler, proven stabilization mechanism for a combined tongue-stabilizing/suction appliance: the patient's own bite on a toothed engagement surface. Substituting Duggan's bite engagement for Hickham's retainer-and-hinge assembly is a simple substitution of one known element for another to yield the predictable result of a self-retaining device — classic KSR. Likewise, Nelson teaches both (i) a wire running inside the suction tube and (ii) mouth-propping, so the "reinforced tube that props/retains" concept was already in the field. Because Hickham identifies cheek retraction at the rearmolar area as a design goal, giving the suction tube a wire core (Nelson; conventional ejectors) so the tube itself can hold the cheek is the routine application of a known structural feature to a known purpose.

B. Claim 7 (apparatus with teeth-propping function) — same combination; Nelson/Duggan supply the prop

Claim 7 adds only the express function of "propping open the teeth" by the bite handle. That function is taught independently by Duggan (bite block raises/locks the jaw open), Nelson (wire frame "aiding in holding the mouth open"), and Dyfvermark (bite-block appliance). Claim 7's remaining limitations mirror claim 1 and are met by the Hickham + Duggan + Nelson combination for the same reasons. Claim 7 is the broadest apparatus claim and is the most vulnerable to an obviousness challenge.

C. Claim 5 (method) — Hickham's own process claim 21 + obvious modifications

Hickham claim 21 already recites a method of (a) expanding cheeks/lips with retractors, (b) retracting the tongue with a tongue retractor supported by the base of the oral cavity, (c) retaining the tongue with a retainer, and (d) removing saliva "along a structural position of said tongue retractor means." The '524 method claim 5 is this same method with two substitutions: (i) stabilizing the shield with a bite handle engaged between the teeth (taught by Duggan/Nelson/Dyfvermark) in place of Hickham's tongue retainer/base support, and (ii) retracting the cheek with the reinforced suction tube itself (Nelson's wire-in-tube + Hickham's cheek-retraction goal). Each substitution is the known use of a known element for its known function; the method as claimed is the obvious procedural analogue of the obvious apparatus. Claim 6 (propping open the teeth) adds nothing beyond the known function of Duggan's/Nelson's bite-engagement structures.

D. Dependent claims

• Claim 2 (second holder/tube + Y-tube adapter): Hickham discloses two saliva ejectors, one at each retractor end; joining two ejector tubes to a single suction source via a Y-connector is a routine plumbing choice in dental operatory suction. Cofresi (3,049,806) also discloses a tubular ejector with inlet orifices on both sides of the teeth — a bilateral suction concept. Obvious.
• Claim 3 (concentric high-volume/low-volume attachments): Providing a dual-size adapter to fit both standard female fittings (LV and HVE) is a conventional design option for operatory suction accessories; the '524 identifies both fitting sizes as "conventional." (Note: claim 3 depends from claim 1 but references the Y-adapter introduced in claim 2 — a drafting artifact that does not affect the obviousness analysis.)
• Claim 4 (stabilizing shelf on the internal surface): Hickham's tongue guides/retainer already position the device relative to the tongue; a shelf is a simple structural expedient for vertical stabilization. Obvious.
• Claims 8–9 (removable bite handle; detachable shield subunits): Hickham's shield plates are pivotally secured (claim 20), teaching adjustability/disassembly of a multi-part shield; Duggan teaches slideably removable/reattachable components on a bite appliance. Making a handle removable or the shield snap-fit for packaging is a routine manufacturing choice. Obvious.
• Claim 10 (separate cheek-retractor means): Expressly disclosed by Hickham (cheek and lip retractors). If not obvious over Hickham alone, it is at least obvious in combination.
• Claims 11–12 (ductile-wire reinforcement; plastic materials): Nelson discloses wire in the tube; conventional saliva ejectors (which the '524 admits are ubiquitous) use ductile-wire-reinforced plastic tubing. Obvious.
• Claims 13–14 (internal vs. external tube attachment): Hickham attaches conduits at/along the retractor ends (internal-type mounting); external gripping holders are shown in the '524's own alternative embodiment and were conventional. Both alternatives are obvious design selections.
• Claim 15 (notched bite handle): Duggan's raised-area ridges for stable tooth engagement are functionally identical to notches. Obvious.
• Claims 16–17 (asymmetric vs. symmetric shield): Hickham's pivotally adjustable plates permit asymmetric positioning; a symmetric arch shield is the default configuration of Cofresi/Nelson-type arch devices. Both are obvious configurations.
• Claims 18–19 (posterior vs. anterior bite engagement): Duggan/Dyfvermark show posterior bite blocks; a forward/anterior handle is an obvious relocation, and '524 itself discloses both in its embodiments. Obvious.
• Claim 20 (extension arm for lateral tube positioning): Hickham's cheek-retractor arms position structure laterally away from the teeth; an extension arm for lateral tube placement is an obvious mechanical equivalent. Obvious.

E. Additional corroborating references

• Cofresi (3,049,806): adds an early example of an arch-spanning multiple-ejector with a tongue-depressor brace — supporting the combination of tongue control with bilateral suction.
• Diamond (4,511,329): confirms the settled idea of combining tongue retraction with lingual saliva suction in a single intraoral instrument.
• Dyfvermark (4,975,057): confirms the settled idea of combining a bite block (teeth-engagement/mouth-prop) with an evacuation aperture.
• NPL "Denta Pops™ Dry Field Aspirator" (May 1993): demonstrates that, immediately before the filing date, the market already had inexpensive disposable dry-field aspirators integrating suction with a mouthpiece/isolation structure — corroborating that the "simple, single-use" design direction of '524 (its own stated objective) was a known market pressure, not an inventive step.

IV. Secondary considerations (Graham factor 4)

No objective indicia of non-obviousness are evident from the record. There is no showing of commercial success, licensing, copying, or unexpected results. To the contrary, the '524 patent lapsed in October 2003 for failure to pay maintenance fees — consistent with the absence of a demonstrated commercial embodiment — and its own later-family continuation work (e.g., US 7,785,105 to the same inventor) was necessary to pursue the dry-field concept further. The specification's "synergistic effect" rhetoric describes the combined benefits of known elements performing their known functions (tongue retraction, suction at the molars, bite stabilization), which under KSR is not enough to defeat obviousness where the combination is predictable.

V. Conclusion

Claims 1, 5, and 7, and all dependent claims, would likely be held obvious under 35 U.S.C. § 103 over the examiner-cited art. The strongest case is:

• Primary: Hickham (5,037,298) — bilateral tongue shield, suction inlets positioned rearward of the rearmost molars, cheek retraction, saliva removal "along a structural position of" the retractor, and an analogous process claim;
• Gap 1 (bite handle / teeth-prop): Duggan (5,152,686) and/or Nelson (4,259,067) — teeth-engaged stabilization and mouth-propping of a tongue-control/suction appliance;
• Gap 2 (reinforcement within the tube wall): Nelson — a wire frame disposed within the saliva-ejection tube — plus the POSITA's background knowledge of conventional ductile-wire-reinforced saliva-ejector tubing (which the '524 itself concedes).

The POSITA's motivation is grounded in the shared problem acknowledged across the references (a stable, full-arch, dry operating field with clear access to the molars), the known simplicity advantage of bite-stabilization over Hickham's hinged assembly, and the known structural capability of wire-reinforced suction tubing. Each substitution yields a predictable result.

Robustness ranking (most to least vulnerable): Claim 7 > claims 1/5 > dependent claims 2–4, 6, 8–20. Claims 2–3 (bilateral + Y-adapter) and 16–17 (arch symmetry) are the most easily shown obvious given Hickham's bilateral ejectors and pivotable plates.

Confidence caveats: (1) I could not independently verify the full disclosures of Reichley (4,215,984) and Neil (4,260,378) within the search budget; my analysis does not depend on them, but they likely further corroborate conventional dual/self-stabilizing suction architectures. (2) Hickham's shield is described as "generally V-shaped" in its claims; treating it as the "generally U-shaped" shield of the '524 claims relies on the insubstantiality of that shape difference and Hickham's own bilateral-arch function — the stronger argument is combination with Nelson/Cofresi, which use arch-conforming shields. (3) This is a paper analysis of the cited art; a definitive validity opinion would require full-text review of all eight references and the NPL, and would be academic in any event because the patent is expired and long since lapsed (no live enforceability, and any post-grant challenge would be time-barred under 35 U.S.C. § 315(b)).