[Comparison between different methods to monitor the microbial level of indoor air contamination in the dental office].

There is no unanimous consensus on the best methodology to monitor the microbial contamination level of the air in the dental offices. Therefore, we compared a precise but expensive and complex active air sampler (Surface Air System--SAS) with a passive method (Air Microbiological Index--AMI) and a microbial parameter of salivary microrganisms, (oral streptococci--OS), with other, more simply detectable, yet more generic, parameters (staphilococci--ST total viable flora--TVF). We tested the various combinations of systems and parameters in three multi-chair dental departments, for two different weekdays, before (T0) and during (T1) the working period. Using non-parametric statistical tests we analysed, (i) the difference between T0 and T1 contamination levels assessed by various methods, in order to confirm their efficacy; (ii) the association between parameters, in order to assess whether generic parameters were as reliable as the specific parameter; (iii) the association between sampling systems, in order to test whether AMI could efficaciously substitute the active samplers. The microbial levels were significantly higher at T1 than at T0, excluding ST assessed by SAS. The parameters were highly inter-correlated. However, for low SO levels, the level of the association of this parameter with the others decreased. The results provided by SAS and AMI were also significantly correlated. However, for low contamination levels this association was not significant. In conclusion, the complex and expensive method (SO level assessed by SAS) seems more reliable for low aerial contamination levels, whereas for high levels, more simple and cheap methods could also be used.