Accuracy of Quantitative Computed Tomography Bone Mineral Density Measurements in Mandibles: A Cadaveric Study
Bibliographic record
Abstract
PURPOSE: The aim was to investigate the accuracy of quantitative computed tomography bone mineral density (BMD) measurements in mandibles, comparing measured BMD with calibrated BMD. MATERIALS AND METHODS: Seventy mandibles from adult cadavers were used. Twenty tomographic cuts were made in each mandible. In each tomographic cut, a region of interest was located, and the bone density was measured in Hounsfield unit (HU). A polymethyl methacrylate phantom containing four inserts of different predetermined densities (hydroxyapatite 100, 200, 500, and 700 mg/cm(3) ) was used to calculate calibrated bone density. Correlation between measured and calibrated bone densities was calculated. RESULTS: Mean total correlation between measured and calibrated BMD in the 20 sagittal tomography cuts showed almost perfect positive correlation (r = 0.998, p < .001). However, when average BMD measurements in HU were compared, the measured total BMD (in the 20 sagittal tomography cuts studied) was 54.99 ± 421.59, whereas the total calibrated BMD was 49.28 ± 364.95, with statistically significant difference (p = .001). CONCLUSIONS: There are discrepancies between measured and calibrated BMD; in this sense, a calibrated bone phantom with a predetermined mineral density should be used to determine the exact BMD before dental implants surgery.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".