Dental restoration / Published data reanalysis
Read the attachment mechanics audit
Construct contraction is distinct from native ligament mechanics
Force and shortening in the construct are algebraically linked. Active contraction and passive modulus cannot establish equivalent tissue function, donor-age effects, regenerated bilateral attachment or stable tooth position.
# Attachment function: an executed mechanics audit, with donor-age gaps retained This batch shifts from transcript directions to physical function. It executes a numerical audit of printed human-cell construct and native-PDL summaries. **No accessed source qualifies for donor-age-by-niche analysis or for jointly verified regenerated attachment and physiological recovery.** The new result is a concrete distinction between active contraction, passive tissue mechanics and durable tooth attachment, with every available numerical row retained. The [plan](analysis_plan.json) is post-source exploratory. The three-source set was frozen after inspection; no additional cohort, download retry, contact, wet-lab work or treatment protocol was pursued. ## Human PDL constructs: force and recovery are different observations [Mulimani et al. 2024](https://doi.org/10.1177/00220345241264792) embedded a heterogeneous, healthy-donor PDL-cell population in collagen between silicone posts. The accessed article describes one donor, without numeric age or sex; construct counts do not create independent people. This is not a purified PDLSC age cohort or a root-cementum/bone attachment model. The reported means imply **777 micrometres shortening, or 9.7125%**, relative to the acellular reference. Multiplying shortening by the modeled post stiffness gives **738.15 micronewtons**, versus 739 reported: a 0.115% difference. The bare-post calculation reproduces 408.5 micronewtons exactly. Force and length are algebraically linked here; agreement does not independently validate contractility. Original SEM labels are retained; no uncertainty in post stiffness, recovery distribution or unsupported sample size is supplied. The article reports partial recovery at 4 h, persistent deformation at 24 h and creep at 1 week. The figure caption gives 5/6/6 constructs for stretch/release panels, but individual before/during/after lengths were not obtained. We do not reconstruct numerical recovery fractions from qualitative descriptions or combine different panels into a same-construct joint endpoint. ## Native human attachment: the reference depends on the test regime [Wu et al. 2018](https://doi.org/10.1186/s12938-018-0607-0) tested 18 slices from 6 incisors from 3 male cadavers aged 31–52. All six Table 2 rows are transcribed with their SDs in the [source extract](source_summary_extract.json). Individual ages and donor-to-tooth-to-slice mapping are unavailable. Four cycles per test are repeated observations. | Peak force / loading rate | Tooth class | E1 mean ± SD, MPa | E2 mean ± SD, MPa | E2/E1 ratio of means | | --- | --- | ---: | ---: | ---: | | 1 N / 1 N·min⁻¹ | Central incisor | 0.67 ± 0.45 | 2.63 ± 0.51 | 3.925 | | 1 N / 1 N·min⁻¹ | Lateral incisor | 0.33 ± 0.20 | 2.32 ± 1.15 | 7.030 | | 3 N / 3 N·min⁻¹ | Central incisor | 1.16 ± 0.73 | 4.50 ± 1.01 | 3.879 | | 3 N / 3 N·min⁻¹ | Lateral incisor | 0.52 ± 0.30 | 2.75 ± 1.16 | 5.288 | | 5 N / 5 N·min⁻¹ | Central incisor | 1.82 ± 1.07 | 5.59 ± 1.23 | 3.071 | | 5 N / 5 N·min⁻¹ | Lateral incisor | 0.81 ± 0.36 | 4.14 ± 1.31 | 5.111 | Between the 1 N and 5 N regimes, E1 means rise 2.716-fold centrally and 2.455-fold laterally; E2 means rise 2.125-fold and 1.784-fold. Peak force and loading rate change together, so this does not isolate a rate effect. Ratios of group means are not distributions of donor-paired ratios. Published branch means span 0.33–5.59 MPa. The discussion's 6.82 MPa upper value equals 5.59 + 1.23, the largest E2 mean plus its SD; no individual extreme can be recovered. The source's “ultimate strain” is the bilinear transition described in its methods, not an observed rupture threshold. Neither range supplies a healthy-function acceptance band. ## Exact endpoint eligibility | Required question | Magnetic construct | Native tensile reference | Viscoelastic PDLSC source | | --- | --- | --- | --- | | Traceable individual donor age and age-by-niche crossing | Missing | Missing individual ages/crosswalk; no niche crossing | Six donors aged 18–30; individual crosswalk and age crossing missing | | Numerical mechanics available here | Printed active-force/calibration summaries | All 6 passive tensile summary rows | Context only; underlying data on request | | Numerical per-construct stretch/release recovery | Not obtained | Not a construct-recovery series | Not obtained | | Regenerated fibers inserted at both mineralized interfaces, jointly linked to mechanics | Silicone posts; absent | Native anatomy present, no numerical insertion/mechanics crosswalk | Not established as a joint physiological endpoint | | Original tooth position after finite support withdrawal | Not measured | Not measured | Not established | [Zhang et al. 2024](https://doi.org/10.1002/advs.202309562) supplies relevant human PDLSC niche context, but cultured-cell responses, material rheology and separate rat replantation histology do not establish human attachment function. Hydrogel stiffness and relaxation vary together. Its data statement offers underlying data on request; no author was contacted, animal outcomes were not pooled with human assays, and no age effect was estimated. The complete [source qualification](source_qualification.json) preserves model, unit, access and endpoint limits. ## What changes in the restoration decision An active force reported in micronewtons is not a passive elastic modulus reported in MPa. The post is a sensor/support, not the tissue. The analysis explicitly withholds a tissue-modulus conversion: matched tissue geometry and a passive tissue force–displacement slope are missing. A large force, increased stiffness or aligned collagen cannot independently pass attachment. The next useful dataset must connect **the same donor-derived construct** to its geometry, independently varied niche, insertion at both mineralized interfaces and recoverable mechanical response. A valid native comparator requires matched fixture, anatomical region, loading regime and tissue state; these cross-source numbers do not establish equivalence. Exact donor age and donor/construct/batch IDs are required before age-by-niche effects are tested. Permanent original tooth pose remains a separate orthotopic outcome, alongside living PDL/cementum/socket attachment, youthful gums, pulp and original tooth substance/architecture. Construct recovery after stretch cannot establish that a damaged tooth returns to its original position or stays there after support is removed. These are unresolved required endpoints, not surrogate successes. ## Reproduce and inspect ```text python -B studies/checklist-function-2026-10-19/attachment/analyze_mechanical_summaries.py python -B -m unittest discover -s tests -p test_checklist_function_attachment.py -v ``` The default analysis uses committed aggregate extracts and the standard library. `extract_numeric_summaries.py` repeats extraction from the ignored cache and verifies all four actual response hashes; analysis `--verify-cache` also checks them. [Results](derived/mechanical_summary_results.json) and the [analysis receipt](derived/analysis_receipt.json) pin inputs, plan and scripts. [Fetch receipts](source_receipts.json) distinguish three obtained primary documents from a retained 1816-byte HTML download-challenge response advertised as DOCX. It is **not** counted as an obtained supplement. XML HTTP 500 and publisher HTTP 403 attempts have no fabricated payload hashes or fetch receipts. Raw files stay in the explicitly scoped ignored cache `data/literature/checklist-function-2026-10-19/attachment/`; no challenge was bypassed and no further retry was made after freezing the source set. Source observations belong to their authors. Wu et al.'s numerical table is attributed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). No source figures or article text are redistributed. These are original calculations on published aggregate observations, not new constructs or wet-lab findings. Docker workbench remains stopped.