Effect of Using Manufacturer-recommended Exposure Times to Photo-activate Bulk-fill and Conventional Resin-based Composites
Bibliographic record
Abstract
OBJECTIVES: To analyze the effect of using the resin-based composite manufacturer's recommended exposure time on the degree of conversion (DC), Knoop hardness (KH), and elastic modulus (E) of conventional and bulk-fill resin-based composites (RBCs). METHODS: Three resin-based composites (RBCs) were tested: Tetric EvoCeram Bulk Fill (TET), Opus Bulk Fill APS (OPU), and RBC Vittra APS (VIT). They were photo-activated in 2 mm deep, 6 mm diameter molds for their recommended exposure times of 10 seconds, 20 seconds, or 40 seconds from four light-curing units (LCUs). Two delivered a single emission peak in the blue light region (Optilight Max and Radii-Cal) and two delivered multiple emission peaks in the violet and blue region (VALO Cordless and Bluephase G2). After 24 hours of dry storage at 37°C in the dark, the KH (Kgf/mm2), E (MPa) and DC (%) at the top and bottom surfaces of specimens (n=5) were measured and the results analyzed by 2-way analysis of variance (ANOVA) followed by a Tukey test (α=0.05). RESULTS: The irradiance (mW/cm2) and spectral irradiance (mW/cm2/nm) from the LCUs were reduced significantly (8-35%) after passing through 2.0 mm of RBC (p<0.001). The DC at the bottom of VIT and TET was less than at the top surface (p<0.001). OPU had the same DC at the top and bottom surface (p=0.341). The KH and E values at the top surface of VIT and TET were substantially higher than at the bottom (p<0.001). OPU exposed for 40 seconds achieved higher mechanical properties than TET that was photo-activated for 10 seconds (p<0.001). The opacity of different bulk-fill RBCs changed differently during the polymerization; OPU became more opaque, whereas TET became more transparent. When exposed for their recommended times, the 2 mm thick RBCs that used Ivocerin or the APS photoinitiator system were adequately photo-activated using either the single or multiple emission peak LCUs (p=0.341). CONCLUSION: After 24 hours' storage, all the 2 mm thick RBCs photo-cured in 6 mm diameter molds achieved a bottom-to-top hardness ratio of at least 80% when their recommended exposure times were used. TET, when photo-activated for 10 seconds, achieved lower mechanical properties than OPU that had been photo-activated for 40 seconds. The change in opacity of the RBCs was different during photo-activation.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".