Removal efficiency of central vacuum system and protective masks to suspended particles from dental treatment

Background High levels of suspended particulate matters (PMs) and bioaerosols are created by dental procedures. The present study aimed to evaluate the size and concentration of PMs produced by drilling and grinding teeth, and to assess the efficiency of central vacuum system and protective masks for the removal of PMs. Methods A total of 20 extracted permanent teeth were collected. A novel experimental system and particle counter were used to evaluate the PMs produced by dental procedures and the PM removal efficiency of a central vacuum system and surgical/N95 masks. Results The number concentration of total PMs produced by drilling and grinding teeth was significantly higher than the indoor background concentration. The average aerodynamic diameter of particle was generally less than 1 mu m. The average number concentration of ultrafine particles was 2.1x10(11) particles/m(3) during tooth drilling and grinding. The efficiency of the central vacuum system was 35.74% for PM >= 0.5 and 35.41% for PM10. For PM >= 0.5, the ratios of inside and outside masks were 0.8-1.34 without vacuum and 1.18-1.36 with vacuum. No difference was found with the use of surgical/N95 masks during dental therapy, with or without vacuum use. Conclusions High levels of PMs were found during tooth drilling and grinding procedures, especially among PM1. The PM removal efficiency of a central vacuum system and surgical/N95 masks were limited.