b>Objective: The aim of this study was to test the effectiveness of a newly developed system, using masking noises with specific frequencies and amplitudes, adjusted to typical noises experienced during dental treatment such as the high-speed hand-held drill. Method and materials: In accordance with an analysis of typical noises experienced during dental treatment, masking noises with specific frequencies (frequency range 0.02 to 20 kHz) and amplitudes were created, with the aim of reducing the patients' awareness of typical treatment noises by overlaying frequencies. Two hundred fifty-four outpatients (113 males, 141 females) with a mean age of 32 years (± 10.5 years) were enrolled in this study. Patients were treated 15 minutes with and 15 minutes without the masking noise. Patients and practitioners filled out questionnaires aimed to evaluate the effectiveness of the system, sensitivity to noise (scale 0 to 10; 0 = effective, 10 = noneffective), psychologic aspects, and statements of fear. Results: There was a significant reduction in patients' awareness of noise using this system during dental treatment. Most of the patients regarded the masking noise as a pleasureable supplementation to common treatment and would select this manner of dental treatment employing the device again (81.5%); 48.2% said they were more relaxed. The system does not, in principle, interfere with dental treatment, and in most instances, the device does not impede the communication between practitioners and patients. Conclusion: The present study demonstrates that using masking noises during dental treatment reduces the sensitivity to drill noise, reduces fear and stress, and may be useful in dental practice as an adjunct to common dental treatment.