Effect of thickness and irradiance on the polymerization delay at the bottom surface of light-cured resin composites
Bibliographic record
Abstract
Objective To examine the effects of the resin-based composite (RBC) thickness and incident irradiance on the time delay after the light turns on before polymerization starts at the bottom surface of the RBC. Methods The degree of conversion (DC) was determined using Fourier-transform infrared spectroscopy (FT-IR) at a rate of 13 measurements per second. Six commercial RBCs were tested at three thicknesses (0.2, 2 and 4 mm) and four incident irradiance values (472–3985 mW/cm 2 ). Results There was a significant time delay before polymerization began at the bottom of each RBC. At 942 mW/cm 2 , representative of many current LCUs, this delay ranged from 0.12 to 1.11 s at the bottom of 2 mm of RBC. When the thickness was increased to 4 mm, even with an irradiance of 1969 mW/cm 2 , which represents high-power LCUs, the delay ranged from 0.12 to 5.17 s. The highest irradiance of 3985 mW/cm 2 did not fully overcome the inherent lag caused by the thickness of the RBC. At 3985 mW/cm 2 , PowerFlow and PowerFill had the shortest delay times of 0.09 s and 0.30 s, respectively, at the bottom of a 4 mm thick RBC. Significance The presence of a time delay before photo-cured RBCs start to polymerize at the bottom surfaces must now be addressed clinically and when calculating reaction rates.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| 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 | 0.000 | 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".