This study aims to compare the gnathological function of edentulous patient rehabilitated according to the full-arch method (Columbus Bridge Protocol™) with immediate loading with that of dentate patients, through at-home night-time monitoring with Bruxoff® device.

Dental implants are now widely used in dentistry for the rehabilitation of partially or totally edentulous arches. These devices have shown excellent clinical success and are considered a reliable long-term treatment(1). In particular, the rehabilitation of the complete arch with immediate loading supported by maxillary implants has now become a safe and reliable procedure capable of rehabilitating the patient with residual or totally edentulous teeth. A fixed prosthesis supported by implants performed according to an immediate loading protocol represents a valid therapeutic option for the rehabilitation of totally edentulous patients, both from the point of view of patient satisfaction and masticatory performance(2,3,4).

Among the various protocols available in the literature, the one called Columbus Bridge Protocol™, developed by the prosthetic school of the University of Genoa, consists in the rehabilitation of one or both jaws with the insertion of a variable number of 4 to 6 dental implants followed by immediate loading(5). This rehabilitation has been documented to be a reliable implant-prosthetic solution in terms of survival and implant success in the medium and long term(2,6). However, considering the current scientific evidence, there is a lack of information relating to possible alterations in muscle activity following this implant-prosthetic rehabilitation.

For the evaluation of EMG activity of the stomatognathic system, the School of Turin has, for a decade now, tested and validated the use of Bruxoff® portable device for the evaluation of nocturnal bruxism, demonstrating a sensitivity and specificity of 91.6 % and 84.6% respectively (7,8).

Bruxoff® is a portable holter that uses 3 recording channels: 2 for recording the surface electromyographic signals (sEMG) of the two masseter muscles with concentric electrodes positioned on the two muscles (CoDe®: Concentric Detection, Spes Medica, Battipaglia, Italy), and one for heart rate detection (ECG) with a strap incorporating three surface electrodes positioned on the left side of the chest (7,13).

Patients who have been rehabilitated with a full-arch for at least 6 months at the Dental School of Turin and subjects waiting for implant-prosthetic rehabilitation of intercalated edentulism (i.e. single-tooth gap) will be involved.

The recordings will be carried out for 3 randomly selected nights within 3 weeks, with at least 4 hours of sleep per night, according to the method evaluated by Deregibus et al. In particular, the subjects will be instructed to perform 3 maximum voluntary contractions (Maximum Voluntary Clenching, MVC) lasting 2 seconds each and spaced by 5 seconds of rest at the beginning of the recording. The highest measurement among the MVCs is used to normalize the EMG values as a percentage of MVCs. The processing of the data will be carried out automatically and standardized using Bruxmeter software (Bruxmeter®, Spes Medica, Battipaglia, Italy) capable of processing the data recorded from the masseter muscles (surface electromyographic signal) and from the heart (cardiotachymetric signal).

Inclusion Criteria:

• Willingness to participate in the study
• Age >18 years
• M/F sex
• Good general state of health
• Absence of clinical symptoms of bruxism, i.e. sore masticatory muscles(10,11)
• Good level of oral hygiene (assessed with FMPS <25%)
• FMBS <25%

Exclusion Criteria (9):

• Age <18 years
• Presence of severe psychiatric pathologies
• Presence of neuromuscular diseases/ severe neurodegenerative diseases
• Presence of diabetes or other metabolic diseases
• Pharmacological treatment with drugs that compromise the neuromuscular system
• Pharmacological treatment with antipsychotic drugs
• Presence of severe chronic diseases
• Cognitive disability
• Acute inflammation
• Presence of an oncological condition
• Smoking (>10 cigarettes per day) Individuals with alcohol or drug addiction will be excluded. Subjects will also be asked not to consume caffeine, alcohol and tobacco in the 6 hours before starting the night recording with Bruxoff®(12).

Patients with implants affected by peri-implant pathology will be excluded from the Test Group.(15) Subjects suffering from periodontal disease (Stage III/IV Grade B/C) will be excluded from the Control Group (16).

The subjects to be included in the study will be chosen from the list of patients rehabilitated according to the immediate-loading full-arch method (Columbus Bridge Protocol™) at the SCDU of Oral Rehabilitation, Maxillofacial Prosthetics and Dental Implantology (University of Turin) (Test Group) and from the list of subjects waiting for implant-prosthetic rehabilitation of intercalated edentulism (i.e. single-tooth implant) (Control Group).

The subjects of the Control Group will be matched with a 1:1 ratio for the variables sex and age (±5 years) to the patients of the Test Group.

Given the nature of the study (i.e. pilot study), the calculation of the sample size was not possible in the planning phase of the study. However, based on the evidence obtained from similar studies(7), 10 subjects per group are considered sufficient to test this method.