The periodicity of enamel laminations in human deciduous molars
Bibliographic record
Abstract
OBJECTIVE: Enamel laminations are closely spaced incremental lines that run parallel to Retzius lines or the developing enamel surface. Here, the timing of enamel laminations is calculated for naturally exfoliated deciduous molars (n = 111) from three modern-day populations (Aotearoa New Zealand, Britain and Canada). DESIGN: Teeth were sectioned using standard histological methods and examined using a high-powered microscope. Mean daily secretion rates (DSR) were calculated for the outer enamel of each molar in cuspal, lateral and cervical enamel regions. These DSRs were used to determine the periodicity of enamel growth across laminations in each region. Lamination periodicity was compared between populations and sexes, and within molars to assess the relationship between lamination periodicity and the angle between laminations and the outer surface. RESULTS: Laminations were present in 57 % of all molars (n = 63 out of n = 111). Their presence did not vary between populations or by sex. A mean two-day periodicity was observed in cuspal and lateral outer enamel sampling regions. A mean one-day periodicity was observed in the cervical outer enamel. The angle of laminations relative to the outermost surface of the enamel was significantly related to the presence of laminations. CONCLUSIONS: A two-day periodicity for laminations indicates that this incremental marking is not a reliable proxy for a circadian 24-hour rhythm in human deciduous molars. The orientation of laminations was similar to Retzius lines but differed to the orientation of cross-striations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".