the lesion in line with long axis of the tooth across the maximum gingival occlusal dimension half of each lesion was removed using a sterile excavator subsequently the remaining lesion was exposed to the ozone gas for a period of either 10 s or 20 s at room temperature 23 u00b0 c and maximum detectable ozone level was also measured using this ozone analyzer the maximum ozone detectable level ppm around the cup from lesions for a period of either 10 s table 1 and fig1 or 20 s table 2 and fig2 ozone application during the treatment of root carious lesions were as follows table 2 maximum ozone detectable level ppm after a 20 s of ozone application teeth types sites ozone detection 20 s lower left lateral labial 0 137 lower left 1 premolar buccal 0 177 lower right incisor labial 0 069 upper right canine labial 0 033 upper right lateral labial 0 079 lower left 2 premolar buccal 0 002 lower right 1 molar buccal 0 083 upper left lateral labial 0 004 lower left canine labial 0 056 upper left 1 premolar mesial 0 001 conclusion the use of a cup is a safe way of delivering ozone when ozone was applied.