Assessment of respirable aerosol concentrations using local ventilation controls in an open multi-chair dental clinic

Figures & data

Figure 1. Local ventilation controls (A) High-Volume Evacuator (HVE), (B) ISOVAC Dental Isolator Adapter (ISO), and (C) Extraoral Suction Unit (EOS).

Figure 2. Room layout for Phase One, illustrating the centrally located procedure operatory (SidePak monitoring) and the neighboring four operatories (pDR monitoring).

Table 1. Procedures and ventilation control devices evaluated in Phase One.

Abbreviation	Name	Model and manufacturer	Operation/Settings
Dental procedures
AWS	Air-Water Syringe	Sure Tip Plus White, 1600; Henry Schein Inc., Carlsbad, CA, USA	–
HSH	High-Speed Handpiece	EVO.15; Bien Air, Irvine, CA, USA	200,000 RPM, 1:1 L; Brassler 330 or 557 burr
RCP	Rubber Cup Polisher	Young Classic Elite Original LF; Young Dental, Earth City, MO, USA	6000 RPM with polishing paste
US	Ultrasonic Scaler	Cavitron Plus Ultrasonic Scaler with Tap-On Technology; Dentsply Sirona, Mississauga, ON, CA	–
Ventilation control devices
EOS	Extraoral dental suction system	EOS, ADS Dental System, Ontario CA	Positioned 3” from mannequin mouth, Power setting: 7 Face Velocity: 2772 fpm Capture Velocity:125 fpm
EOS	Extraoral dental suction system	EOS, VV-1000 Vector R&D Inc, University Place, WA, USA	Positioned 3” from mannequin mouth, Power setting: Green Face Velocity: 2800 fpm Capture Velocity: 170 fpm Power setting: Orange Face Velocity: 4500 fpm Capture Velocity: 230 fpm
HVE	HVE suction	H.V.E. Vacuum Tips, Hager Worldwide, Hickory, NC, USA	Stainless tip 6” Face Velocity: 8500 fpm. Capture Velocity: NA, used within 1 cm of source
ISO	Dental isolation adapter	Isovac 2, Zyris Inc., Santa Barbara, CA, USA	Face Velocity: 550 fpm Capture Velocity: NA, used within 1 cm of source

Note: feet per minute (fpm).

Figure 3. Clinic overview showing sampler deployment and room occupancy during Phase Two of the study.

Table 2. Concentrations, in µg/m³ using SidePak AM520, and significance test results for concentrations measured near the dental assistant during simulated procedures, for the four local exhaust methods and four dental procedures.

	Extraoral		Intraoral		ISOVAC		None		Between procedure differences
Dental Procedure	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Kruskal–Wallis p	ANOVA, Pr > F
Air Water Syringe (AWS)	14.2	3.3	10.0	3.9	13.2	4.7	25.8	11.9	<0.0001	0.0002*	<0.0001*
High Speed Handpiece (HSH)	11.2	1.5	10.6	2.3	26.0	24.9	32.5	18.2
Rubber Cup Polishing (RCP)	3.0	0.8	3.2	0.8	3.1	0.5	3.3	0.3
Ultrasonic Scaling (US)	17.4	1.4	19.5	4.6	16.7	1.4	18.5	2.0

* Tukey–Kramer multiple comparison found that only Rubber Cup Polish concentrations were significantly different from (lower than) AWS, HSH, and Ultrasonic activities. No other differences between procedures.

Table 3. Summary of time-weighted average respirable aerosol concentration in areas adjacent to simulated dental procedures.

Simulated procedure	Local exhaust method	N	Mean	SD
Air Water Syringe	ExtraOral (EOS)	12	1.8	0.2
	Intraoral (HVE)	12	1.8	0.1
	ISOVAC (ISO)	12	1.7	0.2
	None	12	2.1	0.2
	All	48	1.8	0.2
High Speed Handpiece	ExtraOral (EOS)	12	1.6	0.2
	Intraoral (HVE)	12	1.7	0.2
	ISOVAC (ISO)	12	1.9	0.2
	None	12	2.0	0.1
	All	48	1.8	0.2
Rubber Cup Polishing	ExtraOral (EOS)	12	0.9	0.9
	Intraoral (HVE)	12	0.9	0.7
	ISOVAC (ISO)	12	0.6	0.2
	None	12	0.8	0.3
	All	48	0.8	0.5
Ultrasonic Scaling	ExtraOral (EOS)	12	3.8	0.2
	Intraoral (HVE)	12	4.0	0.3
	ISOVAC (ISO)	12	3.7	0.2
	None	12	3.7	0.2
	All	48	3.8	0.3
All Procedures, Combined	ExtraOral	48	2.0	1.1
	Intraoral	48	2.0	1.2
	ISOVAC	48	2.1	1.2
	None	48	2.0	1.2
	All	192	2.1	1.8

All concentrations are in µg/m³ using the pDRs.

Table 4. Time-weighted averages of respirable aerosol concentrations (µg/m³), by occupancy, during Phase Two sampling, using pDRs.

Activities sampled	Patient occupancy, Phase Two
	25%*	50%	Simulated 100%
Background (AM, Mid, PM)	0.09	1.43	2.97
Procedures (AM, PM)	0.13	0.82	2.62
All Day	0.12	1.13	2.73
(Procedure – Background)	0.04	−0.61	−0.35

* Sampler data at location A excluded due to negative concentration readings in pDR on this day.

Data availability

Field data are available upon reasonable request to T. R. Anthony.