Dental malocclusions are not just about small and weak bones: assessing the morphology of the mandible with cross-section analysis and geometric morphometrics
Bibliographic record
Abstract
OBJECTIVES: Dental malocclusions in modern populations would be the result of small and weak jaws developing under low masticatory loads. We assess the validity of this by characterising the external and internal morphology of mandibles affected by class II and III malocclusions and comparing them with those from individuals with different masticatory load patterns. MATERIALS AND METHODS: CTs from up to 118 individuals exerting intensive, medium and low masticatory loads with harmonic occlusion, and from class II and III individuals, were used to compare their external shape using geometric morphometrics, as well as their internal amount and distribution of cortical bone. RESULTS: The low-load groups (harmonic, class II and III occlusion) are externally more gracile than the intense and medium load groups. But more relevant in shape variation is a marked allometric pattern, which differentiates class II (small) and III (large) mandibles. Despite gracility, the relative amount of cortical bone in the low-load groups is larger than in the remaining groups. CONCLUSIONS: There is no evidence that the modern mandible, including class II and III individuals, is intrinsically small and weak. Instead, there is a rather large degree of morphological variation, which could be linked to a lack of constraints derived from low masticatory loads. Thus, the effect of other factors such as genetics, but also basal metabolism, should be looked in more depth. CLINICAL RELEVANCE: Dental malocclusions are a common disorder whose aetiology has not been unravelled, and several to be considered in the prevention and therapy of malocclusion.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".