Objective: To determine psychological aspects influencing patients' choice between Oraqix® anesthesia gel (AG) and injected Ultracain® D-S forte (LA) during non-surgical periodontal therapy (SRP). Primary endpoints were dental anxiety (DA) and injection fear (IF). Secondary endpoint was the assessment of pain during periodontal probing and SRP. Methods: Thirty-eight patients with periodontitis were included in a randomised, single-blind, split-mouth, and cross-over clinical trial. Periodontal probing pain was recorded at baseline by a visual analogue scale (VAS) and verbal-rating-scale (VRS). Additionally, DA and IF were recorded at baseline. SRP was performed in two appointments; once with the use of AG and once with LA. Patients completed questionnaires as to the current and future preferences for local anesthesia. Results: Twenty-two patients (58%) preferred gel, and 14 patients (36%) preferred injection. One patient was indecisive, and 1 patient missed the recall appointment. DA and IF (P = 0.096, P = 0.254, Mann-Whitney) had no influence on anesthesia choice. Pain perception in AG treatment correlated with choice for injection (VAS P = 0.000, VRS P = 0.000, Mann-Whitney). Conclusion: No psychological aspect showed an influence on anesthesia choice. Assessed pain during treatment was found as the only predictor for patients' preference for future local anesthesia use. Keywords: local anesthesia, non-surgical periodontal therapy, SRP, dental anxiety, injection fear, lidocain, prilocain, anesthesia gel