Air Polishing and Aerosol Contamination: What the 2025 Evidence Shows

Air polishing did not increase airborne bacterial contamination above empty-clinic baseline in a 2025 observational study of seven dental procedures. Mensi and colleagues, publishing in the International Journal of Dental Hygiene (DOI 10.1111/idh.12881; PMID 39612250), measured colony-forming units per litre of air after each procedure. The empty-clinic baseline was 1.45 CFU/L. Air polishing, ultrasonic instrumentation, hand instrumentation and rubber-cup polishing produced counts that were not significantly higher. The highest measured contamination, 7.38 CFU/L, came from cavity preparation with a turbine paired with low-volume evacuation. The practical takeaway: routine professional prophylaxis, including air polishing, is not the standout aerosol source in a normally equipped operatory — evacuation choice on restorative procedures is where the airborne bacterial signal actually shows up.

Why the aerosol question matters

Aerosol generation has occupied a disproportionate share of clinical decision-making since 2020. Practices, public health agencies, and accreditation bodies have rewritten standard operating procedures around the assumption that any aerosol-generating procedure in a dental operatory carries an elevated biological-contamination risk. Air polishing — by virtue of using compressed air to deliver a powder slurry — has been swept into that category as a matter of routine, alongside ultrasonic scaling and the high-speed turbine. The clinical-practice question that follows is whether all aerosol-generating procedures are equivalent in measured contamination, or whether some are markedly more burdensome than others. Until the Mensi 2025 data, the empirical answer was largely inferred rather than measured.

This study addresses that gap with direct measurement. It does not say air polishing is aerosol-free — it does say air polishing did not push bacterial CFU/L above the baseline an operatory already produces from ambient turnover and human occupancy. That is a more specific, more useful finding than the prior general framing, and it has direct implications for how clinic managers and hygienists allocate infection-control resources.

Study design and method

The seven procedures evaluated were: air polishing, ultrasonic instrumentation, manual (hand) instrumentation, rubber-cup polishing, cavity preparation using a 1:5 red contra-angle, cavity preparation using a turbine with low-volume evacuation, and cavity preparation using a turbine with high-volume evacuation. For each procedure, the operatory was sampled in its baseline state and again after the procedure. Bacterial loading was reported as CFU per litre of clinic air.

The procedures span the realistic working day of a mixed-practice operatory: hygiene-driven prophylaxis on one end, restorative cutting on the other, with hand and ultrasonic instrumentation in between. The study did not isolate viral aerosols — it counted cultivable bacteria — so it speaks to the broader bacterial-bioburden question rather than to respiratory-virus aerosolisation specifically. That distinction matters when comparing the result to pandemic-era guidance built around viral transmission models.

The numerical picture

The empty-clinic baseline of 1.45 CFU/L is the relevant comparator. Anything that did not push the count significantly above this number was, by the study's standard, not a meaningful contamination source over baseline.

• Air polishing: count not significantly elevated above 1.45 CFU/L baseline.
• Ultrasonic instrumentation: count not significantly elevated above baseline.
• Hand instrumentation: count not significantly elevated above baseline.
• Rubber-cup polishing: count not significantly elevated above baseline.
• Turbine + low-volume evacuator: 7.38 (95% CI 3.87–10.89) CFU/L — the highest contamination measured.

The cleanest reading of these numbers is that procedure type alone is the wrong unit of analysis. A turbine with high-volume evacuation behaves very differently from a turbine with low-volume evacuation. Air polishing, when performed with standard evacuation, falls into the operatory-baseline range. Evacuation, in other words, is doing most of the work — not the type of instrument in the hygienist's hand.

Implications for clinical practice

Three practical consequences follow from these data for a European dental-hygiene practice running an air-polishing protocol.

1. Air polishing is not a special aerosol case

The post-2020 instinct to slot air polishing into the same bucket as turbine restorative work, on aerosol grounds, is not supported by direct measurement. Aerosol-mitigation practices still apply — PPE, evacuation, ventilation — but they apply because they apply to operatory hygiene in general, not because air polishing is a standout contamination source. For background on the broader safety framing, see our overview at is air polishing safe.

2. Evacuation choice is the variable that matters

The study's most striking signal is the gap between low-volume and high-volume evacuation on the same turbine procedure. Low-volume evacuation produced the worst measured contamination of any condition tested. The same logic should be applied to air polishing: standard high-volume evacuation should be the default whenever the device and operatory layout support it. This is consistent with our wider protocol comparison, which treats evacuation discipline as a baseline expectation across all hygiene workflows.

3. Mechanism still matters — powder choice and pressure remain part of the conversation

Aerosol bacterial counts are one slice of the safety question. Powder abrasivity, tissue tolerability, and surface compatibility are independent questions that the Mensi 2025 study does not address and that air polishing literature handles separately. For powder-specific selection, see how to choose the right prophy powder, the comparison in erythritol versus glycine clinical evidence, and the device-side considerations in the subgingival air polishing guide.

What the 2025 study does not settle

It is worth being precise about scope. A single observational study from one clinical environment is informative, not definitive.

• Viral aerosols: the bacterial-CFU endpoint does not directly address respiratory virus transmission risk. Respiratory-virus protocols should continue to follow national infection-control guidance independently.
• Equipment variation: the study did not test every air polisher available in the market. Different devices — for example combined tabletop systems versus dedicated air-polishing handpieces — have different evacuation requirements and different default powder-air pressures. A comparison of those system architectures is in our cordless vs tabletop air polishers review.
• Subgingival versus supragingival: the study did not break down air polishing by depth or nozzle type. The aerosol footprint of supragingival stain-removal work may differ from that of a sub-gingival nozzle delivering a glycine slurry into a 5 mm pocket. Procedure granularity remains an open research question.
• Operator variability: a single-clinic observational design does not capture operator-driven variation in technique, posture, suction discipline, or patient positioning. These remain plausible modifiers of any measured aerosol signal.

How this fits the existing aerosol literature

The Mensi 2025 result is consistent with a more measured emerging picture. A 2025 systematic review and meta-analysis of aerosol-mitigation strategies in dental procedures, published in the American Journal of Infection Control, concluded that integrated preventive strategies — high-volume evacuation, pre-procedural mouth rinses, ventilation upgrades — meaningfully reduce microbial burden across the dental operatory in aggregate. The throughline across both papers is that the variable doing the work is not "procedure category" but the engineering and behavioural controls that surround the procedure. Evacuation, ventilation, PPE, and patient selection move the dial; switching from air polishing to ultrasonic, or vice versa, does not — at least not on bacterial CFU.

For clinic managers planning protocol upgrades — whether driven by regulatory pressure, post-pandemic policy review, or a quality-improvement audit — the practical implication is to allocate investment to evacuation capacity and ventilation, not to procedure substitution. Equipment-level investment context for that decision is in the total cost of ownership analysis and the 2026 air polisher buyer's guide.

What hygienists should take away

For practising hygienists, the working interpretation is straightforward. Maintain standard PPE. Use high-volume evacuation as the default on every aerosol-generating procedure, air polishing included. Screen patients for active respiratory infection on the day of treatment. Beyond that, the procedure-substitution arguments that have circulated since 2020 — "do hand instrumentation instead of ultrasonic, skip air polishing, defer prophylaxis" — are not supported by the direct bacterial-CFU measurement here. The signal that does emerge is about turbine work and evacuation, which is a restorative-side rather than hygiene-side issue.

Equipment and protocol checklist

A practical, evidence-aligned checklist for air-polishing aerosol management in routine prophylaxis:

• High-volume evacuation by default. Confirm the operatory's suction line and HVE tip are functional and the assistant or hygienist is positioned to maintain effective evacuation during the procedure.
• Standard PPE. Mask, eye protection, and shield as per local guidance. Aerosol level matters less than maintaining the baseline practice.
• Patient selection. Screen for active respiratory infection. Defer elective prophylaxis where indicated. See who should get air polishing and is air polishing safe for the broader contraindication discussion.
• Pre-procedural rinse. A chlorhexidine or essential-oil pre-rinse remains a low-cost adjunct supported by the wider aerosol-mitigation literature.
• Operatory ventilation. Functional HVAC and adequate air exchanges per hour materially reduce post-procedure airborne load. Consider this an environmental control, not a procedure-by-procedure variable.
• Powder selection still matters for non-aerosol reasons. For implants, follow the powder-safety logic at can you use air polishing on implants and sodium bicarbonate on implants. For routine prophylaxis powder selection, see how to choose prophy powder.

Conclusion

The 2025 observational data from Mensi and colleagues reframe the air-polishing aerosol question with direct measurement. Air polishing, ultrasonic instrumentation, hand instrumentation and rubber-cup polishing all sit at or near the empty-operatory baseline of 1.45 CFU/L of air. The procedure that pushed bacterial counts the highest — to 7.38 CFU/L — was a turbine paired with low-volume evacuation, which is a restorative workflow with sub-optimal evacuation rather than a hygiene workflow. The clinically actionable conclusion is that infection-control investment should be evacuation-led and ventilation-led, not procedure-substitution-led. Air polishing remains an evidence-supported prophylaxis modality, and the post-2020 instinct to treat it as a special aerosol case is not supported by the direct bacterial-CFU evidence currently in print. Standard precautions and high-volume evacuation remain the working framework — and within that framework, air polishing is operating well inside the safety envelope.