Introduction: Local anesthetics are used to alleviate pain, but the prick of the injection delivering anesthesia is known to cause anxiety and pain that affect dental treatment. The most difficult aspect of pediatric dentistry is minimizing discomfort while the intraoral local anesthetic is administered. This pain has been treated using physical, psychological, pharmacological, and combinations of these approaches. Recently, the idea of vibration, which is based on the gates control theory, has gained popularity as a way to reduce discomfort while local anesthesia (LA) is being administered. Aim: The aim of this trial was to evaluate the efficacy of mucosal vibrators in children aged 6–10 years to alleviate pain associated with LA administration. Materials and methods: A total of 60 patients aged 6–10 years requiring inferior alveolar nerve block were enrolled for this randomized, single-blind clinical trial. In group I, before and during LA administration, the customized mucosal vibrator was placed at the injection site. In group II, the topical local anesthetic gel was applied to the injection site prior to the administration of LA. Then, the local anesthetic solution was deposited using a disposable syringe needle on both groups. The pain was evaluated using the physiological scale (pulse rate and oxygen saturation), the subjective scale (Wong–Baker scale), and the objective scale [Face, Legs, Activity, Cry, Consolability (FLACC) scale] by an experienced assistant who was unaware of the procedure. Results: A customized mucosal vibrator along with local anesthetic injections resulted in significantly less pain (p = 0.001*) when compared with the injections with topical anesthetic gel. Conclusion: The results show that the customized mucosal vibrator is an effective and inexpensive means to reduce pain during LA administration.