The Efficacy of LED Light Polymerization Units in Private Dental Offices in Toronto, Canada
Bibliographic record
Abstract
Light-emitting-diode (LED) light-polymerization units (LPUs) are currently routinely used for resin-based composites (RBC) photopolymerization. This study aimed to determine the effectiveness of LED-LPUs used in participating private dental practices in Toronto, Canada. One-hundred dental practices were recruited, and 113 LED-LPUs were examined. Part 1 evaluated radiant exposure (RE) of participants’ LED-LPUs. Majority of LPUs (n=87, 77%) passed the study-required criterion (delivering equivalent to 16 J/cm2 in 20s). A strong, negative correlation between LPUs' age, light-probe damage, and RE was found. Part 2 evaluated operator's technique to deliver 8 J/cm2 of RE in 10s to simulated restorations before and post-instructional. Before instructions, 73.6% of participants delivered required-energy to anterior restoration, and 32.2% of participants delivered required-energy to posterior restoration. Following instructions, 94.3% of participants delivered required-energy to anterior restoration, and 73.6% of participants delivered required-energy to posterior restoration. Part 3 examined relative-hardness (RH) of two RBCs polymerized at 1mm and 4mm, tip-to-target distance. Both RBCs polymerized at 1mm had average RH (ratio of mean lower/upper surface hardness) greater than 0.80, but not at 4mm tip-to-target distance. Part 4 evaluated the diametral tensile strength (DTS) of two RBCs polymerized with participating LED-LPUs. No significant difference between mean DTS values of two RBCs was observed. Mean DTS values were highly correlated among the LED-LPUs tested. In conclusion, 23% of LED-LPUs tested were deemed as incompetent for sufficient RBC polymerization. A high percentage of dental practitioners failed to deliver 8 J/cm2 in 10s exposure cycle, even after receiving specific instructions (5.7% to anterior restoration and 26.4% to posterior restoration). The outcome was due to a combination of LPUs performance and operator's technique. This finding is alarming as it relates well to early failure of Class-2 RBC restorations due to insufficient polymerization.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".