Objective: To compare pain levels between the conventional injection and the Morpheus® device for the nasopalatine nerve block concerning the puncture, needle introduction, and local anesthetic (LA) deposition. Methods: A crossover, double-blind, randomized clinical trial was carried out involving 32 participants. Group I comprised the conventional syringe (control group), while Group II comprised the Morpheus® device (experimental group). The study was developed in two sessions, two weeks apart. The pain was assessed using a 100-mm Visual Analog Scale (VAS). The intragroup analyses were performed using Friedman’s test and Durbin-Conover's post hoc test. The Wilcoxon test was used for intergroup analyses. The significance level was set at p < 0.05. Results: Intragroup analyses showed statistical differences within both groups (Group I, p < 0.001; Group II, p = 0.003). All the evaluated moments of both injection techniques differed statistically, except between the needle introduction and LA deposition within Group II (p = 0.526). In the intergroup analyses, participants of Group I presented higher pain levels, experiencing the highest pain at the LA deposition moment (median 58; 46 - 62). Pain levels were statistically significant between all the corresponding moments of the groups (p < 0.001). Conclusion: Computerized injection with the Morpheus® can be effectively employed to increase comfort during anesthetic injections and patient compliance with dental treatments.