Background and Aim: The placement of dentist during injection is effective on patient’s anxiety. So this research was conducted to compare the effect of standing in front or behind the patient while administering MINB injection on patient’s anxiety at the surgery department of Dental branch of Islamic Azad University in 1392-93. 

Materials and Methods: In this randomized splitmouth clinical trial study, 40 adults with complete awareness of study procedure, were entered in to the study. The patient’s anxiety was determined by a 17item BISS questionnaire .The patients were allocated to the case (injection from behind) and controls (injection from the front) groups by a randomized method. The effect of operator position during injection on the anxiety of patients, was measured at the end of injections and the rate of anxiety was determined. The data was analyzed using MANN-U- WHITNEY test by SPSS version 20. 

Results: The mean changes of anxiety score after injection versus patients statements before injection in group that their injection was from behind, 0.85±0.12 reduced and in the group whose injection was from the front, 0.4±0.74 increased. (P=0.007) 

Conclusion: Probably the patient’s anxiety in MINB injection, for groups whose injection was from behind, was significantly lower than patients whose injections was from front. 

Keywords: Dentist Patient Relations, Injection, Anxieties, Dental.