## 4 Discussion
If a positional patient had spent most of the night with the MAD in a non-supine position, the observed reduction in AHI could be attributed to the change in position during sleep and not just to the effect of the MAD. In our sample, no statistically significant differences were found between the means of the percentage of time spent in the supine position initially (44.6 \(\pm\) 18.7) and finally (42.6 \(\pm\) 21.1), with a \(p\)-value of 0.5738, indicating weak statistical significance (\(p\) > 0.10). From the analysis of this parameter, we can conclude that the patients included in the study maintained their positional habits during sleep despite the application of the device, and that the improvement in polysomnographic outcomes is attributable to the effective action of the F22 MAD. As recommended by the AASM (American Academy of Sleep Medicine), the device was designed to be customized based on the intraoral characteristics of each patient, and titratable, meaning it can be gradually adjusted for advancement [10]. This is achieved through modifications of the position of the metal pin present in the upper plate, tailored to the specific needs of the patient. The literature affirms that the extent of advancement exhibits a dose-dependent effect on the efficacy of the Mandibular Advancement Device (MAD), although this must be balanced against the potential increase in side effects [39]. It is believed that an approach to titration characterized by minimal and gradual increments over time constitutes the preferred method for identifying the optimal level of advancement, with a view to improving polysomnographic outcomes and related symptoms. The F22 MAD emerges as a suitable option for straightforward and simplified titration, efficiently manageable by both the patient and the practitioner, obviating the need for complex components such as screws and connectors. The operator can adjust the degree of device advancement by selecting the numbered upper block most appropriate to the patient's specific clinical needs (STEP 0, +1, -1, etc. ), with lower production costs compared to other MAD devices available on the market. Concerning design, the current literature does not provide specific indications for the optimal device design. The American Academy of Sleep Medicine (AASM) merely recommends the use of customizable and titratable devices, which can be monoblock or bi-block in nature. The F22 MAD takes the form of a customizable and adjustable bi-block device, equipped with an anterior advancement mechanism that prevents mouth opening and permits lateral movements. A particular study has demonstrated that bi-block MAD devices allow greater lateral mobility compared to monoblock variants [40]. Consequently, bi-block devices appear to have a significantly reduced impact on dental pain, occlusal function, and discomfort related to bulkiness, as they enable the masticatory and facial muscles to maintain their physiological rhythmic activity during sleep, thus promoting proper salivary lubrication. This increased freedom of movement appears to enhance patient comfort, reduce the sensation of confinement, and encourage adherence to therapy. Furthermore, to achieve optimal therapeutic outcomes, it is crucial to counteract vertical mouth opening using the device. While many devices require the patient to use vertical elastics, the F22 MAD, owing to its anterior interlocking mechanism between the upper block pin and the lower block slot, prevents mouth opening and maintains good retention while minimizing posterior elevation. The device's slim profile, coupled with good retention and mechanical durability, enhances patient comfort and therapy adherence. Additionally, thanks to the lateral movement capabilities offered by the device, the F22 MAD is a suitable choice for patients affected by nocturnal bruxism.