Pain control is achieved typically by means of injection of local anesthesia for invasive procedures to carry out procedures with as little pain or discomfort as possible. Although this method is highly effective, patients often fear more from the sight of a needle during administration of local anesthetic than from the treatment. Therefore, needleless local anesthesia with a jet injection device has been proposed. With the INJEX (R), anesthetic solution is forced under high pressure into the oral mucosa, leading to mechanical infiltration of the compound through the mucosa. With this study, we aimed to show the effectiveness of the needleless injection for infiltrative anesthesia and compare the acceptance and efficacy between jet injection with INJEX and local infiltration anesthesia. 28 adult patients admitted to our department for tooth extraction were included in the study. Two symmetrical teeth in the same jaw were extracted from each of the patients. Jet injection with the INJEX (R) was performed on one side and classical (needle) infiltration anesthesia on the other side with 0.3 cc Ultracain DS forte (Sanofi Aventis, Istanbul, Turkiye) on buccal and lingual aspects and 0.1 cc on palatal aspects of the teeth. The difference between pain and discomfort scores experienced during tooth extraction was statistically significant (P = 0.026). Accordingly, the pain or discomfort score of the INJEX (R) method during tooth extraction was significantly higher. Jet injection with the INJEX (R) was not found to be effective for local infiltrative anesthesia especially teeth extractions. It may be more acceptable when using for previously classical local infiltration anesthesia by patients. The main problem with jet injection was the "pop" sound when the INJEX (R) device was pressed, and also inadequate suppyling the anesthesia. (C) 2019 Elsevier Masson SAS. All rights reserved.