Table 1.

Concentrations of heterotrophic plate counts (HPCs) at 22 °C and 36 °C (colony-forming units (CFU)/mL), L. pneumophila (CFU/L) and P. aeruginosa (CFU/100 mL) in water from hand-pieces and tap water.

		Mean ± SD	Min–Max	Median	Interquartile Range	p Value
HPCs at 22 °C	Hand-piece	1168.53 ± 906.00	145–3200	881.5	548–1710	<0.001
	Tap water	385.27 ± 836.41	2–2880	37.5	15–200
HPCs at 36 °C	Hand-piece	827.90 ± 746.87	27–2116	518.5	109–1620	<0.001
	Tap water	242.93 ± 241.64	2–1860	9.5	5–121
P. aeruginosa	Hand-piece	25.13 ± 77.75	0–308	0	0–0	0.26
	Tap water	0	0–0	0	0–0
L. pneumophila	Hand-piece	676.67 ± 746.34	0–2700	350	200–1300	0.15
	Tap water	343.33 ± 313.69	0–900	300	0–700