Effects of ionizing radiation on mechanical proprieties of restorative materials and enamel in upper molars: an in-vitro study
Bibliographic record
Abstract
Introduction: Radiotherapy is one of the most commonly used treatment modalities for head and neck cancer patients, but the effects of ionizing radiation on restorative tooth materials and enamel are largely unknown.Objectives: This study aimed to assess the effects of ionizing radiation on mechanical properties of restorative materials and enamel in upper molars.Material and methods: A total of 60 extracted human molar teeth (40 with minor occlusal caries and 20 non-carious) were used in this study.Teeth were randomly divided into three groups, including group 1 (control group, samples received no restorative materials), group 2 (teeth were restored in-vitro with glass ionomer cement), and group 3 (teeth were restored in-vitro with flowable resin composite).Each group was divided into two sub-groups: those irradiated with a single dose of 70 Gy and those non-irradiated.Rockwell hardness tests and radiodensity measurements on Hounsfield scale were applied to the teeth before and after irradiation.A compression test was done at the end of the experiment.Results: Radiation therapy caused significant reductions in the surface hardness in the two restorative groups (p < 0.001).Hounsfield units in the flowable resin composite group markedly decreased after radiation (p < 0.001).However, no significant effects in compressive strength were observed in any group treated with radiation.Conclusions: These results showed that radiation has negative effects on the mechanical properties of the teeth.The surface hardness was significantly depressed by ionizing radiation.Since the radiodensity in Hounsfield scale was markedly diminished in the flowable resin composite group, glass ionomer cement could be a better alternative for cementation in teeth subjected to radiation.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".