This study was carried out in accordance with the fundamental principles of the Declaration of Helsinki. It was approved before commencement by the Ethics Committee of the University of L’Aquila, Italy (no. 16137/2016). One hundred and fifteen patients aged 6–16 years were clinically examined at the Dental Clinic of the University of L’Aquila, Italy. The same clinician performed all examinations. Examinations included the acquisition of dental panoramic radiographs according to European guidelines on radiation protection in dental radiology, extraoral and intraoral photographs, and alginate impressions of both dental arches. Based on these data, the orthodontist created a treatment plan specific to each patient, following the index of orthodontic treatment needs described by Brook and Shaw . The following exclusion criteria were applied: IOTN (INDEX OF ORTHODONTIC TREATMENT NEED) index > 4; presence of epilepsy, systemic disease, TMD, or periodontal disease; and lack of written informed consent from a parent or legal guardian. Inclusion criteria were: skeletal and dental class II malocclusion (divisions 1 and 2); and the presence of OV and OB. Ultimately, 60 patients aged 7–15 years were enrolled in the study, and separated into test and control groups. The test group included 30 patients (14 males, 16 females; mean age, 10.66 ± 2.12 years), who were treated with the EQ Series II. The control group included 30 patients (15 males, 15 females; mean age, 10.76 ± 2.52 years), who were treated with the Occlus-o-Guide. The two groups exhibited the same orthodontic features. OJ and OB were evaluated at two timepoints: T0 (before starting therapy) and T1 (after 1 year). Alginate impression of the dental arches of the two groups were taken by the same orthodontist (AM) at T0 and T1. Dental stone models were constructed using white stone. Plaster models were sent to DTW (Dental Team Work, Preturo, L’Aquila) for scanning and conversion to 3D virtual models using ITero Intraoral scanning. Variables of the study were OJ and OB, which were evaluated using this virtual digital technique.
Each patient in the test group received a medium hardness, orange EQ class II device that was suitable for their dentition phase . This device had a similar shape to a mouthguard, and embraced both dental arches, reaching distally to cover the last molars present in the arch. There are several measures, based on the distance between the palatal cusps of the first premolars. The patient fits the upper and lower splints over their teeth. The device is activated by biting, depending on the soft elastic forces generated by muscle energy. The activator is worn overnight. The equilibrator is a type of orthodontic appliance that stimulates growth and, through the input of muscle movements, elicits tissue development toward a suitable chewing function. Biting this elastomeric device balances tension to the sphenobasilar synchondrosis, based on osteopathic medicine and philosophy .
Each patient in the control group received a G-type (for mixed dentition) Occlus-o-Guide device, depending on their dentition phase. This devise is constructed from an elastomeric material. It is a preformed activator that is considered ideal for use in the early to late mixed dentition phase. This appliance is available in various sizes. The most appropriate size is chosen by measuring the distance between the distal wall of the upper left lateral incisor and the distal wall of the upper right lateral incisor. It is also possible to measure it using the lower lateral incisors. All measurements are completed using a special ruler provided by the manufacturer. Along with the activator properties of this device, it is ideal for correcting class II malocclusion, because it is based on tooth size. These appliances are called EGAs (Eruptive Guidance Appliances), as they also function as a positioner, correcting overbite, and correcting mild to moderate crowding. This device provides depressive forces to the front teeth, while simultaneously causing the posterior elements to erupt in their optimal vertical position. It is necessary, however, to intervene when they erupt, before the periodontal fibers stabilize the definitive vertical level of posterior elements. It is also a myofunctional regulator that tends to properly rebalance muscle forces. It rehabilitates the posture of the tongue, re-educates atypical swallowing, and stimulates correct breathing. The patients were instructed to use the device overnight [5, 8, 9]. The orthodontist checked patients every 30 days to evaluate eventual modifications for optimize the execution of the device.