## 3 Results
### Applications in Dental Phobia  
It is estimated that 50-60% of individuals suffer from a specific fear of dental procedures and dental-related stimuli, or from a mild to severe grade of dental anxiety [35; 36]. Fear-related behaviours are considered the most difficult aspect of dental patient management and may interfere with good dental care since the patient with dental phobia (named \"odonto-phobia\") goes to the dentist when the clinical situation is severe. The therapeutic techniques, considered most effective in the treatment of phobias and fears, are the In Vivo Exposure Therapy (IVET) and the Virtual Reality Exposure Therapy (VRET). IVET is a technique based on direct patient confrontation with an object or series of anxious situations to reduce the consequent anxious reaction. This exposure therapy is considered the gold standard therapy in the treatment of specific fears related to the dental care situation [37]. Recently, VRET has become a viable alternative to IVET in the treatment of specific phobias [38]. Using computer-generated VR environments, the patient is gradually exposed to situations which are potentially sources of anxiety [39]. Compared to IVET, VRET is safer because the patients face the virtual representation of their threat more gradually in a controlled manner [40]. VRET is known to elicit a feeling of being \"present\" in the virtual environment, and this represents the main factor for the effectiveness of VRET [41]. Clinically, techniques such as cognitive-behavioural treatments, nitrous oxide, and intravenous sedatives administered during dental treatments have been found to minimize patient pain and discomfort during dental care [42; 43]. In addition to these invasive methods, distracting patients with a movie has been shown to help reduce pain in some medical procedures and during laboratory studies of pain [44]. Following the same concept, VR can serve as an effective non-pharmacologic analgesic for dental pain [45]. Several studies reported that VR reduced their awareness of dental pain and that they were so absorbed in the VR that they did not think often about their pain [46; 47; 48]. The patient's inability to see the dental practitioner and instruments may be one advantage of VR. The effectiveness of VR distraction treatment may depend on how patients feel in the virtual environment [49]. For this reason, video stimulation and audio simulation may be detrimental in making the users' experience more immersive and by trying to decrease the dental pain [8]. For VR application, it is advisable to produce sound in three dimensions, specifically in the binaural format.  
The audio in three dimensions allows the users to hear the sound of objects according to their position in the virtual space. The use of the binaural format, which reproduces the immersive audio with simple headphones, without the aid of a complex hardware set up, will create a greater reality of the VR environment [8]. Consequently, the effectiveness of VR in distracting the patient from medical treatment will be greater. [PERSON] et al. confirmed that 3D sound increases people's sense of immersion in virtual reality [50]. The study showed that people felt more immersed in virtual realities with spatial sound than in virtual realities with non-spatial sound [50; 51]. Moreover, the soundtrack in an immersive audio, more than the stereo format, increases the possibility of modifying the patient's state of mind. Therefore, an adequate sonorization of the VR environment will favour a state of calm and relaxation.