Effect of aging on discoloration of two composite surface sealants

Objectives Composite surface sealants were introduced aiming to prevent or decrease the discoloration and microleakage of composite restorations. This study sought to assess the effect of aging on discoloration of two composite surface sealants.Methods In this experimental study, 24 samples were fabricated of Fortify Plus and BisCover LV composite surface sealants (10 mm in diameter and 1 mm in thickness) and their baseline color coordinates were measured using the CIE L* a* b* system by a reflection spectrophotometer. The samples made of each material (n = 12) were randomly divided into 4 groups of 3 and aged in xenon chamber, tea, distilled water and dry ambient environment (control). Color change (ΔE*) was calculated in the reflectance mode. The data were analyzed using two-way ANOVA and t-test (P < 0.05).Results The minimum ∆E* value was 0.95 ± 0.6 belonging to Fortify Plus stored in the dry ambient environment while the maximum ∆E* value was 21.85 ± 4 belonging to BisCover LV aged in tea. Two-way ANOVA showed significant differences in ∆E* among the aging protocols (P < 0.001); the effect of two materials (P < 0.001) and the interaction effect of the type of material and aging were also significant (P = 0.001). Conclusions It can be concluded that aging affects the discoloration of composite surface sealants. Tea caused the greatest discoloration. There were no significant differences in the color change of the two materials after accelerated aging with xenon

Microleakage of Bulk-Fill Composites at Two Different Time Points

Objectives: Microleakage is the main concern in composite restorations. This study aimed to compare the microleakage of two bulk-fill and one conventional composite at two different time points.Methods: Class II cavities were prepared in 60 premolar teeth and divided into six groups of 20. Groups 1 and 4 were incrementally filled with Grandio composite. Groups 2 and 5 were filled with X-tra fil bulk-fill composite. Groups 3 and 6 were filled with Tetric-N-Ceram bulk-fill composite in one layer. The samples were thermocycled for 5000 cycles between 25-55°C. In groups 1-3, the samples were incubated for 24 hours and then immersed in 1% methylene blue dye. Groups 4-6 were incubated for three months and then immersed in dye. All samples were mesiodistally sectioned and degree of microleakage was scored under a light microscope. The data were analyzed using Mann Whitney and Kruskal-Wallis tests.Results: The results showed no significant difference among groups 1-5 and 6 in terms of microleakage (P>0.05) but a significant difference was noted between groups 1 and 4 in this regard (P=0.01). The microleakage in groups 4-6 was higher than that in groups 1-3 (P=0.02). Also, microleakage in gingival margins was greater than that in occlusal margins (P=0.02).Conclusion: The microleakage of bulk-fill composites is comparable to that of conventional composites both at 24 hours and three months after restoration

Cluster Analysis Revealed Two Hidden Phenotypes of Cluster Headache

ObjectiveTo investigate the possible subgroups of patients with Cluster Headache (CH) by using K-means cluster analysis. MethodsA total of 209 individuals (mean (SD) age: 39.8 (11.3) years), diagnosed with CH by headache experts, participated in this cross-sectional multi-center study. All patients completed a semi-structured survey either face to face, preferably, or through phone interviews with a physician. The survey was composed of questions that addressed sociodemographic characteristics as well as detailed clinical features and treatment experiences. ResultsCluster analysis revealed two subgroups. Cluster one patients (n = 81) had younger age at diagnosis (31.04 (9.68) vs. 35.05 (11.02) years; p = 0.009), a higher number of autonomic symptoms (3.28 (1.16) vs. 1.99(0.95); p < 0.001), and showed a better response to triptans (50.00% vs. 28.00; p < 0.001) during attacks, compared with the cluster two subgroup (n = 122). Cluster two patients had higher rates of current smoking (76.0 vs. 33.0%; p=0.002), higher rates of smoking at diagnosis (78.0 vs. 32.0%; p=0.006), higher rates of parental smoking/tobacco exposure during childhood (72.0 vs. 33.0%; p = 0.010), longer duration of attacks with (44.21 (34.44) min. vs. 34.51 (24.97) min; p=0.005) and without (97.50 (63.58) min. vs. (83.95 (49.07) min; p = 0.035) treatment and higher rates of emergency department visits in the last year (81.0 vs. 26.0%; p< 0.001). ConclusionsCluster one and cluster two patients had different phenotypic features, possibly indicating different underlying genetic mechanisms. The cluster 1 phenotype may suggest a genetic or biology-based etiology, whereas the cluster two phenotype may be related to epigenetic mechanisms. Toxic exposure to cigarettes, either personally or secondarily, seems to be an important factor in the cluster two subgroup, inducing drug resistance and longer attacks. We need more studies to elaborate the causal relationship and the missing links of neurobiological pathways of cigarette smoking regarding the identified distinct phenotypic classes of patients with CH

COVID-19 vaccination-related headache showed two different clusters in the long-term course: a prospective multicenter follow-up study (COVA-Head Study)

Abstract Background Although acute headache following COVID-19 vaccination is widely acknowledged, the long-term progression of these headaches remains poorly understood. Our objective was to identify various phenotypes of prolonged or worsened headaches associated with COVID-19 vaccination and document any changes in these phenotypes over an extended period. Additionally, we aimed to document the diverse headache presentations among patients with pre-existing primary headaches. Methods A multinational, prospective observational study was conducted to investigate prolonged or worsened headaches associated with COVID-19 vaccination. Questionnaires assessing COVID-19 vaccination-related headaches at three time points (initial visit, 3rd month follow-up, and 6th month follow-up) were developed for the study. Headache specialists/clinicians evaluated patients using these questionnaires in a prospective manner. Repeated K-means cluster analysis was performed to identify patient profiles with prolonged or worsened headaches related to COVID-19 vaccination. Results Among the 174 patients included in the study, there was a female-to-male ratio of 128 (73.6%) to 46 (26.4%). The mean age of the patient group was 45.2 ± 13.3 years, and 107 patients (61.5%) had a pre-existing history of primary headaches. Through the analysis, two major clusters were identified based on headache characteristics at each visit. During the first visit (n = 174), Cluster 1 primarily comprised patients with a history of primary headaches, frontal localization of pain, throbbing pain type, more severe headaches accompanied by symptoms such as nausea, phonophobia, photophobia, and osmophobia, and worsened by physical activity. In contrast, Cluster 2 consisted of patients with longer headache durations (over one month) and a stabbing/pressing quality of pain. Patients in Cluster 1 had a higher prevalence of migraine as the pre-existing primary headache disorder compared to Cluster 2 (90.48% vs. 68.18%, respectively; p = 0.005). Conclusion The identification of two distinct phenotypes of prolonged or worsened headaches related to COVID-19 vaccination can provide valuable clinical insights. Having an awareness of the potential worsening of headaches following COVID-19 vaccination, particularly in patients with a primary headache disorder such as migraine, can help clinicians and headache experts anticipate and adjust their treatment strategies accordingly. This knowledge can aid in preplanning treatment modifications and optimize patient care