Dental aerosols: microbial composition and spatial distribution

Figures & data

Figure 1. Floor plan of the four dental clinics with the placement of agar plates during treatment (passive sampling) and the location of the BioSampler® during active sampling. Passive sampling an active sampling was not performed on the same day. The dental assistant was present in clinic 1 and 3

Table 1. Mean (SD) Log₁₀ of bacterial counts per growth method per location and moment

	Clinic 1			Clinic 2			Clinic 3			Clinic 4
	mean CFU/plate (SD)			mean CFU/plate (SD)			mean CFU/plate (SD)			mean CFU/plate (SD)
	Aerobe	Anaerobe	R2A	Aerobe	Anaerobe	R2A	Aerobe	Anaerobe	R2A	Aerobe	Anaerobe	R2A
Passive sampling
Time point
Before treatment	1.1 (0.5)	1.0 (0.7)	1.3 (1.1)	0.8 (0.5)	0.7 (0.7)	0.9 (0.9)	1.1 (0.9)	1.0 (1.0)	1.3 (1.0)	−0.1 (−0.4)	0.1 (−0.3)	0.1 (−0.3)
After treatment	1.1 (0.8)	0.8 (0.6)	1.0 (0.7)	1.0 (0.8)	0.9 (0.6)	1.1 (1.1)	1.4 (1.1)	1.3 (1.1)	1.3 (0.9)	0.5 (0.2)	−0.1 (−0.1)	0.2 (−0.3)
Location (during treatment)
Chest 30 cm	2.8 (2.7) ^a,b	2.8 (2.7) ^a,b	2.6 (2.6) ^a,b	2.4 (2.4) ^a,b	2.1 (1.1) ^a,b	1.4 (2.7) ^a,b	2.7 (2.7) ^a,b	2.6 (2.7) ^a,b	2.7 (2.7) ^a,b	1.2 (1.2)	1.4 (15)	0.5 (0.4)
Instrument plate	1.4 (1.1) ^a,b	1.4 (1.0) ^a,b	1.3 (0.9) ^a,b	1.6 (1.9) ^a,b	1.3 (1.0) ^a,b	1.5 (1.9) ^a,b	1.5 (1.9) ^a,b	1.5 (1.9)^a,b	1.4 (1.9) ^a,b	0.3 (0.2)	0.7 (1.0)	−0.1 (0)
Control 150 cm	1.2 (1.0)	1.2 (1.1)	1.3 (1.0)	1.2 (0.9)	1.1 (0.9)	1.1 (0.9)	1.3 (1.3)	1.2 (1.3)	1.0 (0.9)	0.2 (−0.2)	0.2 (0.2)	0.1 (−0.1)
Active sampling (during treatment)
	mean CFU/m^3 (SD)			mean CFU/m^3 (SD)			mean CFU/m^3 (SD)			mean CFU/m^3 (SD)
50 cm from oral cavity	2.4 (2.7)	1.8 (2.2)	2.1 (2.5) ^a,b	2.2 (2.0) ^a,b	1.9 (2.0)	2.2 (2.0)	2.5 (2.5)^a,b	1.9 (2.1)	2.6 (3.3)^a,b	1.6 (1.4)	1.4 (1.6)	0 (0)

^aSignificant higher count compared to baseline.

^bSignificant higher count compared to follow up (Mann–Whitney U-test, p < 0.05).

Table 2. Mean, modus and range of number of different taxa identified per sampling time or sample moment. Values are based on all clinics grouped together

	Before treatment	After treatment	Control	Chest	Instruments	Active samples
Human derived taxa (HDT)
Mean	5	5	6.13^a	9	6.64	4.97^a
Modus	5	7	4	7	4	5
Range	1–9	0–10	1–25	1–21	1–15	2-11
Water derived taxa (WDT)
Mean	2.1	2	2.5	2.7	2.57	1.43^a
Modus	1	2	2	2	2	1
Range	1–4	0–7	0–6	0–7	0–6	0–9

* = significant higher number compared to chest sampled area (post-hoc analyses, Bonferroni corrected p < 0.05.

Table

Bacterial genera identified as originating from the human microbiome (oral; skin) per sample
30 min before first treatment
Actinomyces		Aerococcus			Arthrobacter				Bacillus		Brevibacterium
Capnotytophaga		Clostridium			Corynebacterium				Dermabacter		Dermacoccus
Dietza		Enterococcus			Fastidiospilia				Kocuria		Micrococcus
Nesterenkonia		Pantoea			Paracoccus				Rhodococcus		Rothia
Staphylococcus		Streptococcus
30 min after end of treatment
Actinomyces		Aerococcus			Arthrobacter				Bacillus		Brachybacterium
Brevibacterium		Clostridium			Corynebacterium				Dermabacter		Dermacoccus
Fastidiospilia		Frigoribacterium			Gordonia				Granulicatella		Kocuria
Macrococcus		Micrococcus			Nesterenkonia				Paracoccus		Rhodococcus
Selenomonas		Staphylococcus			Streptococcus				Veillonella
During treatment, at 150 cm from head of the patient
Actinomyces		Aerococcus			Anaeroglobus				Arthrobacter		Bacillus
Brachybacterium		Brevibacterium			Campylobacter				Corynebacterium		Dermacoccus
Dialister		Dietza			Eikenella				Fastidiospilia		Fusobacterium
Gemella		Granulicatella			Kocuria				Lactobacillus		Macrococcus
Micrococcus		Neisseria			Nesterenkonia				Pantoea		Paracoccus
Parvimonas		Peptostreptococcus			Prevotella				Prevotella		Serratia
Staphylococcus		Streptococcus			Veillonella
During treatment, on chest area
Actinomyces		Aerococcus			Anaeroglobus				Arthrobacter		Bacillus
Bifidobacteria		Brachybacterium			Brevibacterium				Campylobacter		Capnocytophaga
Corynebacterium		Dermabacter			Dermacoccus				Dialister		Eikenella
Enterobacter		Enterococcus			Fastidiospilia				Frigoribacterium		Fusobacterium
Gemella		Granulicatella			Haemophilus				Kocuria		Lactobacillus
Megasphaeara		Micrococcus			Negativicoccus				Neisseria		Neomicrococcus
Nesterenkonia		Oribacterium			Paeniglutamicibacter				Pantoea		Paracoccus
Parvimonas		Pasteurellaceae			Peptostreptococcus				Prevotella		Rhodococcus
Selenomonas		Staphylococcus			Stomatobaculum				Streptococcus		Veillonella
During treatment, instrument area
Aerococcus		Anaeroglobus			Arthrobacter				Bacillus		Bifidobacteria
Brachybacterium		Brevibacterium			Campylobacter				Capnocytophaga		Corynebacterium
Dermabacter		Dermacoccus			Dialister				Eikenella		Enterobacter
Enterococcus		Fastidiospilia			Frigoribacterium				Fusobacterium		Gemella
Granulicatella		Haemophilus			Kocuria				Lactobacillus		Megasphaeara
Micrococcus		Negativicoccus			Neisseria				Neomicrococcus		Nesterenkonia
Oribacterium		Paeniglutamicibacter			Pantoea				Paracoccus		Parvimonas
Pasteurellaceae		Peptostreptococcus			Prevotella				Rhodococcus		Selenomonas
Staphylococcus		Stomatobaculum			Streptococcus				Veillonella
During treatment, active sampling
Actinomyces	Aerococcus			Arthrobacter				Bacillus			Brachybacterium
Corynebacterium	Dermabacter			Dermacoccus				Dolosigranlum			Enterobacter
Enterococcus	Fastidiospilia			Gemella				Gordonia			Granulicatella
Kocuria	Micrococcus			Neisseria				Nesterenkonia			Pantoea
Paracoccus	Rhodococcus			Serratia				Staphylococcus			Streptococcus
Streptomyces	Veillonella
Bacterial genera identified as originating from the water microbiome per sample
30 min before first treatment
Acinetobacter			Brevundimonas			Caulobacter	Cutibacterium			Enhydrobacter
Moraxella			Sphingomonas			Sporosarcina	Virgibacillus
30 min after end of treatment
Acinetobacter			Bacilus			Brevibacillus	Chryseobacterium			Cutibacterium
Enhydrobacter			Finegoldia			Hymenobacter	Roseomonas			Sphingomonas
Sporosarcina
During treatment, at 150 cm from the head of the patient
Acinetobacter			Brevibacillus			Brevidumonas	Chryseobacterium			Cutibacterium
Deinococcus			Delftia			Enhydrobacter	Finegoldia			Flavobacterium
Hymenobacter			Massilia			Paenibacillus	Pseudomonas			Psychrobacter
Roseomonas			Solibacillus			Sphingomonas	Stenotrophomonas			Virgibacillus
During treatment, on chest area
Acinetobacter			Caulobacter			Chryseobacterium	Delftia			Enhydrobacter
Finegoldia			Hymenobacter			Lysinibacillus	Massilia			Pedobacter
Pseudomonas			Roseomonas			Sphingomonas	Sporosarcina			Stenotrophomonas
During treatment, instrument area
Acinetobacter			Anaerococcus			Brevibacillus	Brevudimonas			Chryseobacterium
Cutibacterium			Delftia			Enhydrobacter	Fictibacillus			Hymenobacter
Lysinibacillus			Lysobacter			Paenibacillus	Pedobacter			Promicromonospora
Pseudomonas			Psychrobacter			Roseomonas	Solibacillus			Sphingomonas
Stenotrophomonas
During treatment, active sampling
Acinetobacter			Brevudimonas			Chryseobacterium	Cutibacterium			Elizabethkingia
Enhydrobacter			Exiguobacterium			Finegoldia	Hymenobacter			Paenibacillus
Pseudomonas			Pseudoxanthomonas			Roseomonas	Sphingomonas			Stenotrophomonas
Virgibacillus
Dental unit waterline effluent water
Bosea			Brevudimonas			Caulobacter	Delftia			Elizabethkingia
Flavobacterium			Methylobacterium			Sphingomonas	Stenotrophomonas