Low Arousal Threshold Estimation Predicts Failure of Mandibular Advancement Devices in Obstructive Sleep Apnea Syndrome.

Introduction: The treatment of choice for obstructive sleep apnea syndrome (OSAS) is continuous positive airway pressure (CPAP). However, CPAP is usually poorly tolerated and mandibular advancement devices (MADs) are an alternative innovative therapeutic approach. Uncertainty still remains as to the most suitable candidates for MAD. Herein, it is hypothesized that the presence of low arousal threshold (low ArTH) could be predictive of MAD treatment failure. Methods: A total of 32 consecutive patients, with OSAS of any severity, who preferred an alternate therapy to CPAP, were treated with a tailored MAD aimed at obtaining 50% of their maximal mandibular advancement. Treatment response after 6 months of therapy was defined as AHI < 5 events per hour or a reduction of AHI ≥ 50% from baseline. Low ArTH was predicted based on the following polysomnography features, as previously shown by Edwards et al.: an AHI of 82.5% and a hypopnea fraction of total respiratory events of >58.3%. Results: There were 25 (78.1%) responders (p-value < 0.01) at 6 months. Thirteen patients (40.6%) in the non-severe group reached AHI lower than 5 events per hour. MAD treatment significantly reduced the median AHI in all patients from a median value of 22.5 to 6.5 (74.7% of reduction, p-value < 0.001). The mandibular advancement device reduced AHI, whatever the disease severity. A significant higher reduction of Delta AHI, after 6 months of treatment, was found for patients without low ArTH. Conclusions: Low ArTH at baseline was associated with a poorer response to MAD treatment and a lower AHI reduction at 6 months. A non-invasive assessment of Low ArTH can be performed through the Edwards' score, which could help to identify an endotype with a lower predicted response to oral appliances in a clinical setting.

Orofacial pain induced by Eagle syndrome in an elderly patient with temporomandibular disorders - a case report.

BACKGROUND: Eagle syndrome (ES) is a rare disorder that can be responsible for orofacial pain. OBJECTIVE: To describe the treatment of an elderly patient affected by ES and temporomandibular disorders (TMD). MATERIALS AND METHODS: A patient complained of constant pain of the right temporomandibular joint (TMJ) and of the sensation of having a foreign body in the throat. Based on the patient's medical history and symptoms, a TMJs internal derangement and concomitant ES were suspected. A magnetic resonance and a computerised tomography confirmed the clinical diagnosis. A conservative treatment was initially performed to re-establish a functional occlusion. RESULTS: The rehabilitative treatment alleviated the pain almost totally. A slight residual uncomfortable sensation of the presence of a foreign body in the throat persisted after the oral rehabilitation but without any influence on the quality of life. CONCLUSION: In elderly patients complaining a chronic orofacial pain, the possibility of a concomitant TMD and ES has to be considered to correctly identify the source of pain. A conservative approach to identify weather TMD is the main source of pain is preferable, avoiding unnecessary invasive treatments.

Eagle's syndrome: signs and symptoms.

Eagle's syndrome, an uncommon sequela of an elongated styloid process, can manifest itself as a sensation of a foreign body in the throat and a retrogoniac or anterolateral neck pain often referred to the TMJ and the ear. When treating patients affected by temporomandibular disorders (TMD), complaining of atypical orofacial pain, and with a concomitant radiographic finding of a bilaterally elongated styloid, the possible coexistence of Eagle's syndrome should always be considered. The aim of this review is to present an overview of the epidemiology, pathophysiology, diagnosis, and therapy for Eagle's syndrome and to help the clinician in differential diagnosis with other conditions that can provide similar signs and symptoms.

Effects of deflection and archwire dimension on the mechanical performance of two self-ligating orthodontic systems.

OBJECTIVES: To analyze the effects of archwire deflection and dimension on the mechanical performance of two self-ligating systems, as passive and active ligation designs. MATERIALS AND METHODS: An experimental model was used that was designed to resemble the full dental arch and to allow vertical displacement of a canine element. Two self-ligating systems were investigated: 1) a passive system; and 2) an active system, both in combination with three thermoactive NiTi archwires, with round sections of 0.014-in, 0.016-in and 0.018-in. The full loading-unloading cycles consisted of either 3mm or 6mm maximum deflection, performed at 37 °C. During unloading, the deactivation forces and energy were recorded. The ratio between the deactivation and activation energies was used as representative of the mechanical efficiencies of the systems. RESULTS: The deactivation force increased in combination with larger archwires and greater deflection. The deactivation energy increased in combination with larger archwires only for the 3-mm deflection cycle, while for the 6-mm deflection cycle, the deactivation energy was not influenced by the archwire dimension, and was not greater than that of the 3-mm deflection cycle. The mechanical efficiency decreased in combination with greater deflection and larger archwires, with a maximum decrease of about 12%. Only minor comparative differences were seen between the systems. CONCLUSIONS: The deflection degree and archwire dimension have large effects on the mechanical performance of self-ligating systems.

Combined aging effects of strain and thermocycling on unload deflection modes of nickel-titanium closed-coil springs: an in-vitro comparative study.

INTRODUCTION: There are no reports on the aging effects of thermocycling of nickel-titanium (NiTi) based coil springs, and few studies have investigated their superelasticity phases in full. In this study, we compared the mechanical properties of NiTi-based closed-coil springs after the combined aging effects of prolonged strain and thermocycling, as a reflection of the clinical situation. METHODS: Ninety NiTi-based closed-coil springs were used, 30 each of the following types: (1) Nitinol (3M Unitek, Monrovia, Calif), (2) Ni-Ti (Ormco, Glendora, Calif), and (3) RMO (Rocky Mountain Orthodontics, Denver, Colo); all had similar dimensions (length, 12 mm). In each sample group, 2 equal subgroups of 15 coil springs were extended by either 50% (to 18 mm) or 150% (to 30 mm), immersed in artificial saliva, and kept at 37°C for 45 days. All springs underwent sessions of 1000 thermocycles (1 minute long) from 5°C to 55°C on days 22 and 45. Unload deflection curves from both the 50% and 150% extensions (according to their strain subgroups) were recorded by using a universal testing machine before the strain (baseline) and at both 22 and 45 days, immediately after thermocycling. RESULTS: At baseline, the loads exerted by the NiTi-based coil springs varied from 99.8 to 245.1 gf for the RMO (50% strain) and Ni-Ti (150% strain) groups. Statistically significant, although small, differences were seen at each time point in both the 50% and 150% strain subgroups; generally, the highest and lowest values were recorded in the Ni-Ti and Nitinol groups (all, P <0.001). Only the Nitinol coil-spring group showed an acceptable superelasticity phase. The strain and thermocycling did not dramatically change the deactivation forces of any coil springs. CONCLUSIONS: NiTi-based closed-coil springs might not have a superelasticity phase, and prolonged strain and thermocycling do not produce clinically relevant alterations in their deactivation forces.