When using C-CLADS to perform a periodontal ligament anesthesia , the drug dosage and the severity of injection pain were significantly less than those of conventional manual infiltration anesthesia [ drug dosage : ( 0.340.09 ) ml vs. ( 0.550.13 ) ml , P < 0.01 ; VRS : 0.420.73 vs. 1.380.92 , P < 0.01 ; VAS : 1.341.21 vs. 3.101.70 , P < 0.01 ] .