de Oliveira MT, Pereira JR, Ghizoni JS, Bittencourt ST, Molina GO. Effects from exposure to dental amalgam on systemic mercury levels in patients and dental school students. Photomedicine and Laser Surgery. 2010 Oct;28 Suppl 2:S111-S114.
Dental teams handle amalgam every day—mixing, placing, polishing, and removing it. Patients also encounter a concentrated exposure when old amalgam is drilled out. Brazilian researchers asked a practical question: do urine mercury levels rise after a student’s first occupational contact with amalgam, and after patients undergo amalgam removal? Their 2010 study used cold-vapor atomic absorption spectrophotometry (CVAAS) on paired urine samples to look for short-term systemic changes.
What the study found
The team collected 40 urine samples from 20 subjects, arranged as four related groups:
- G1A / G1B (n = 10): dental students before and after their first occupational contact with silver amalgam.
- G2A / G2B (n = 10): patients needing restorations, sampled before and after amalgam removal.
A statistically significant difference appeared among the dependent groups (p = 0.0038). The authors report that mercury levels increased considerably after the first occupational contact of all subjects. Even so, they conclude that urine mercury remained below biologic-tolerance limits in every participant—while still framing occupational amalgam work as a potential risk for raising systemic mercury.
[Paywall note: Full text is behind Mary Ann Liebert / Photomedicine and Laser Surgery access. Exact pre/post urine mercury concentrations (µg/L or µg/g creatinine) were not available for verification beyond the PubMed abstract; do not treat this summary as a substitute for the paper’s tables.]
Why it matters for SMART
SMART is built for the moments this study highlights: the student’s first clinic day with amalgam and the patient’s removal appointment. Both involve vapor and particulate that can be absorbed. The finding that levels rose after contact—even when still within tolerance—supports treating amalgam work as an exposure event that deserves barriers, high-volume suction with water, air controls, and PPE, rather than routine “drill and fill” without protection. For training clinics and private practices alike, the message is preventive hygiene from day one—not waiting until biomarkers look alarming.
Practical takeaways
- Treat first contact as real exposure — Students and assistants need full mercury hygiene on their earliest amalgam cases.
- Protect patients during removal — Removals were part of the paired design; ask for SMART-aligned chairside protections.
- Monitor the workplace — Urine or other biomonitoring (when clinically indicated) can flag rising occupational burden.
- Stay below limits ≠ zero risk — Levels within tolerance still rose after contact; minimize dose whenever possible.
- Pair training with engineering controls — Ventilation, scrap storage, and separators complement personal technique.
Bottom line: de Oliveira and colleagues showed a statistically significant rise in urine mercury after first amalgam contact and after removal—yet still within biologic tolerance—reinforcing why SMART-style precautions matter for both dental trainees and patients.