Irradiance Differences in the Violet (405 nm) and Blue (460 nm) Spectral Ranges among Dental Light‐Curing Units
Bibliographic record
Abstract
ABSTRACT Problem: Previous studies identified nonuniformity in the irradiance at the tip end of a variety of dental light‐curing units (LCUs) and correlated those differences with potential clinical implications, but the spectral dependence of the irradiance uniformity has not yet been addressed. Purpose: This study examined the irradiance uniformity across emitting tips of LCUs at two emission wavelengths, 405 and 460 nm. Two broadband emission light units (quartz‐tungsten‐halogen [QTH] and plasma arc [PAC]), and four commercial light‐emitting diode (LED)‐type LCUs were examined. Materials and Methods: The spectral radiant power from six LCUs was measured using a laboratory grade spectroradiometer (Ocean Optics, Dunedin, FL, USA). The spatial and spectral characteristics of irradiance across the emitting tips of these light units were recorded through 10‐nm wide bandpass filters (centered at 405 nm [violet] or 460 nm [blue]) using a laser beam analyzer (Ophir‐Spiricon, Logan, UT, USA). Irradiance distributions were reported using two‐dimensional contour and three‐dimensional isometric color‐coded images. Irradiance uniformity at the tip end was determined using the Top Hat Factor (THF) for each filtered wavelength. Results: Irradiance distributions from the QTH and PAC units were uniformly distributed across the tip end of the light guide, and THF values, measured through the 405 and 460‐nm filters, were not significantly different. However, the three polywave LED units delivered non‐uniform irradiance distributions with THF values differing significantly between the 405 and 460‐nm emission wavelengths for each unit. Areas of nonuniformity were attributed to the locations of the various types of LED chips within the LCUs. Conclusion: All three polywave LED units delivered a nonuniform irradiance distribution across their emitting tip ends at the two important emission wavelengths of 405 nm and 460 nm, whereas the broadband light sources (QTH and PAC) showed no evidence of spectral inhomogeneity at these wavelengths. CLINICAL SIGNIFICANCE Since the rate and extent of polymerization of photo activated restorative materials is highly dependent on delivering radiant energy at specific wavelengths, the nonuniform spectral distribution across the emitting tips of polywave light‐emitting diode curing lights may affect the resulting properties of some photocured resins and their potential for long‐term clinical success. (J Esthet Restor Dent 22:363–378, 2010)
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".