Dataset for: Myricetin as a Radioprotective Biomodifier for Irradiated Human Root Dentin: Implications for Restorative Care in Head and Neck Oncology
Description
This dataset was generated to test the hypothesis that ionizing radiation, as used in head and neck cancer radiotherapy, compromises the mechanical, enzymatic, and adhesive properties of human root dentin, and that myricetin (MYR), a naturally occurring flavonoid, can mitigate these deleterious effects through antioxidant, anti–matrix metalloproteinase (MMP), and collagen-stabilizing mechanisms. The dataset includes quantitative measurements obtained from an in vitro experimental model using human third molars. Root dentin specimens were allocated to non-irradiated controls or irradiated groups exposed to single cumulative doses of 20, 40, or 60 Gy. For each radiation condition, samples were evaluated either without treatment or after application of 600 µM myricetin for 120 seconds. Mechanical behavior was assessed by three-point bending tests, providing flexural strength, strain, and elastic modulus values. Enzymatic degradation was evaluated through a fluorometric assay measuring total MMP activity in dentin. Adhesive performance was analyzed using microtensile bond strength testing of resin–dentin interfaces, performed both at 24 hours and after thermocycling, along with failure mode classification. The data show a clear dose-dependent effect of radiation, characterized by significant reductions in flexural strength, elastic modulus, and microtensile bond strength, accompanied by increased dentin deformation and marked activation of MMPs, particularly at 60 Gy. Myricetin-treated specimens demonstrated partial or complete recovery of biomechanical parameters, significant suppression of MMP activity, and preservation of adhesive performance comparable to non-irradiated controls, even after aging. Failure mode distributions shifted toward cohesive failures within the resin in myricetin-treated groups, indicating improved interfacial integrity. All raw data are provided in spreadsheet format, organized by experimental group and outcome variable, allowing independent statistical reanalysis or secondary use. This dataset can be used to explore radiation-induced alterations in dentin biomechanics, enzymatic activity, and adhesion, as well as to support the development and validation of biomodification strategies aimed at improving restorative outcomes in irradiated dental tissues.
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Steps to reproduce
Human third molars extracted for therapeutic reasons were collected under institutional ethical approval and stored at 4 °C in 0.9% NaCl containing 0.02% sodium azide for no longer than three months. Teeth free of caries, restorations, or structural defects were selected. After crown removal, root portions were used for all analyses. Specimens were mounted on custom 3D-printed supports to expose the cervical root dentin and assigned to non-irradiated controls or irradiated groups. X-ray irradiation was performed using a medical linear accelerator (Radixact X9, Accuray Inc.) delivering 2 Gy per day until cumulative doses of 20, 40, or 60 Gy were reached, simulating clinical head and neck radiotherapy protocols. Artificial saliva was applied before each irradiation session. Non-irradiated samples were handled identically without radiation exposure. Following irradiation, dentin specimens were sectioned under water cooling using a low-speed diamond saw to obtain standardized beams for mechanical testing (2 × 2 × 10 mm) and blocks for MMP activity assays (3 × 3 × 1 mm). Dimensions were verified with a digital caliper. Samples were randomly allocated to experimental subgroups. Myricetin treatment was performed using a freshly prepared 600 µM solution dissolved in absolute ethanol. Specimens were immersed or surface-treated with myricetin for 120 s, rinsed with phosphate-buffered saline, and stored until testing. Control specimens received ethanol or buffer alone. Mechanical behavior was evaluated using three-point bending tests in a universal testing machine equipped with a 5 kN load cell. Flexural strength, strain, and elastic modulus were calculated from stress–strain curves recorded at a crosshead speed of 0.75 mm/min. Matrix metalloproteinase activity was quantified using a fluorescence resonance energy transfer–based assay. Dentin blocks were incubated with a fluorogenic substrate, and fluorescence was measured using a microplate reader. APMA-treated samples served as activation controls, and results were expressed as relative fluorescence units. For microtensile bond strength testing, cervical root dentin was restored using an ethanol-based universal adhesive in self-etch mode and a resin composite applied incrementally. Restored teeth were sectioned into microbars (≈1 mm²), half of which were thermocycled (10,000 cycles, 5–55 °C). Microtensile testing was performed at 0.5 mm/min, and failure modes were analyzed under stereomicroscopy. Raw data were recorded in spreadsheet format. Statistical analyses were performed using standard software, including normality testing and appropriate parametric or nonparametric comparisons, with significance set at p ≤ 0.05.
Institutions
- Universidad Nacional de ColombiaBogota D.C., Bogotá
- Fundación Santa Fe de BogotáBogota D.C., Bogotá