Retraction: Eagle Syndrome: A Rare Cause of Stroke in a Young Patient.

[This retracts the article DOI: 10.7759/cureus.21102.].

Influence of ZrO2 Nanoparticle Addition on the Optical Properties of Denture Base Materials Fabricated Using Additive Technologies.

This study investigated the translucency of 3D-printed denture base resins modified with zirconium dioxide nanoparticles (ZrO2NPs) under thermal cycling. A total of 110 specimens were fabricated and divided into 3 groups according to the materials, i.e., heat-polymerized resin, and 3D-printed resins (NextDent, and ASIGA). The 3D-printed resins were modified with 0, 0.5, 1, 3, and 5 wt.% of ZrO2NPs. All the specimens were subjected to 5000 thermal cycles. The translucency was measured using a spectrophotometer. The results showed that the heat-polymerized resin had considerably higher translucency than the 3D-printed resins. Compared to the unmodified group, the translucency decreased significantly after adding 5% ZrO2NPs to NextDent and 3% ZrO2NPs to ASIGA resins. The highest translucency was achieved for NextDent by adding 0.5% ZrO2NPs and for ASIGA without any ZrO2NPs. It was found that the average concentration level in ASIGA was significantly higher than that in NextDent. These findings revealed that 3D-printed resins have lower translucency than heat-polymerized acrylic resin, and adding ZrO2NPs at low concentrations did not affect the translucency of the 3D-printed resins. Therefore, in terms of translucency, 3D-printed nanocomposite denture base resins could be considered for clinical applications when ZrO2NPs are added at low concentrations.

3D-Printed Nanocomposite Denture-Base Resins: Effect of ZrO2 Nanoparticles on the Mechanical and Surface Properties In Vitro.

Due to the low mechanical performances of 3D-printed denture base resins, ZrO2 nanoparticles (ZrO2NPs) were incorporated into different 3D-printed resins and their effects on the flexure strength, elastic modulus, impact strength, hardness, and surface roughness were evaluated. A total of 286 specimens were fabricated in dimensions per respective test and divided according to materials into three groups: heat-polymerized as a control group and two 3D-printed resins (NextDent and ASIGA) which were modified with 0.5 wt.%, 1 wt.%, 3 wt.%, and 5 wt.% ZrO2NPs. The flexure strength and elastic modulus, impact strength, hardness, and surface roughness (µm) were measured using the three-point bending test, Charpy's impact test, Vickers hardness test, and a profilometer, respectively. The data were analyzed by ANOVA and Tukey's post hoc test (α = 0.05). The results showed that, in comparison to heat-polymerized resin, the unmodified 3D-printed resins showed a significant decrease in all tested properties (p < 0.001) except surface roughness (p = 0.11). In between 3D-printed resins, the addition of ZrO2NPs to 3D-printed resins showed a significant increase in flexure strength, impact strength, and hardness (p < 0.05) while showing no significant differences in surface roughness and elastic modulus (p > 0.05). Our study demonstrated that the unmodified 3D-printed resins showed inferior mechanical behavior when compared with heat-polymerized acrylic resin while the addition of ZrO2NPs improved the properties of 3D-printed resins. Therefore, the introduced 3D-printable nanocomposite denture-base resins are suitable for clinical use.

Eagle Syndrome: A Rare Cause of Stroke in a Young Patient.

Stroke is a common acute neurological injury that may develop due to arterial thrombosis or hemorrhage. However, it is uncommon in the young population. The etiologies of stroke in young patients are different compared with those for the elderly population. They include various non-atherosclerotic angiopathies, hematological conditions, and inflammatory disorders. We report the case of a 26-year-old man who presented to the emergency department because he noticed that his right hand had become clumsy. He first noticed this symptom five days before his presentation, but he noticed that his symptom had improved significantly since it began. He reported that he had episodes of neck pain and pain around the ear. He visited the family physician clinic several times for this complaint and was diagnosed as having a temporomandibular joint disorder. Neurological examination revealed decreased muscle strength in the right upper limb with a power of 4/5 along with a sensory deficit. The coordination was intact. No gait ataxia was noted. Considering the patient's age, the initial diagnosis was a demyelinating disorder such as multiple sclerosis. The patient underwent magnetic resonance imaging of the brain. It demonstrated an increased signal intensity in the territory of the left middle cerebral artery representing a left-sided infarction. Subsequently, the patient underwent computed tomography angiography of the head to rule out any structural malformation. The scan showed the presence of an elongated styloid process that appeared in close proximity to the neck vasculature. These radiological findings are consistent with Eagle syndrome. The patient underwent surgical resection of the styloid process. Eagle syndrome is a rare clinical condition that may have a myriad of clinical presentations. A high index of suspicion for this condition is vital to reach the diagnosis. Physicians should keep this condition in the differential diagnosis of stroke in the young population with no risk factors.