Effect of different polishing methods on roughness and color stability of air-abraded restorative materials after artificial accelerated aging.

PURPOSE: To evaluate the effect of air abrasion and polishing procedures on roughness and color stability of ceramic and composite materials after artificial accelerated aging. METHODS: In this study, six restorative materials were tested: feldspathic ceramic (CEREC Blocks), glass ceramic (IPS e.max CAD), resin-based hybrid ceramic (Cerasmart), microhybrid composite (Charisma Classic), nanohybrid composite (Charisma Diamond) and nanoceramic composite (CeramXOne). Forty square-shaped composite specimens were fabricated from each composite and CAD-CAM ceramic material. Initial surface roughness measurements were performed using a profilometer and color measurements of each specimen with a spectrophotometer. Ten control specimens for each group did not receive air abrasion. The other specimens were treated by an air abrasion device and then were randomly divided into three subgroups of 10 specimens (n= 10). After air abrasion, 10 specimens of each group did not receive polishing (Air abrasion group) and others were repolished with Sof-Lex kit (Sof-Lex group) or a rubber kit (Rubber group). Surface roughness and color measurements were repeated before and after 300 hours of artificial accelerated aging (AAA). The univariate test and then three-way ANOVA and two-way ANOVA were performed for comparison of groups (α= 0.05). RESULTS: The univariate statistical analysis revealed that the restorative materials were differently affected after air abrasion, polishing methods and AAA (P< 0.001). Three-way ANOVA showed that the surface roughness of the restorative materials increased after air abrasion and AAA (P< 0.001). Two-way ANOVA showed statistically significant differences between color changes of ceramic (CEREC and IPS e.max CAD) and composite based restorative materials (P< 0.001). CLINICAL SIGNIFICANCE: Clinicians should be aware that air abrasion at a specified power and time significantly changes the surface roughness of the materials except for CEREC. Additionally, polishing procedures (Sof-Lex, Rubber) did not significantly reduce the surface roughness of the ceramic groups. After air abrasion, depending on the material type used clinically, restorations should be repolished to reduce roughness and ensure color stability.

Correlation between clinical disease activity and sacroiliac magnetic resonance imaging detection in axial spondyloarthropathy.

Objectives: The study aimed to evaluate the correlation between the clinical disease activity of axial spondyloarthropathy (axSpA) and magnetic resonance imaging findings of the sacroiliac joint. Patients and methods: Thirty-two patients (21 males, 11 females; mean age: 39.3±9.2 years; range, 18 to 55 years) who were diagnosed with axSpA according to the Assessment in Spondyloarthritis International Society classification criteria between November 2015 and August 2017 were included in this cross-sectional study. Visual Analog Scale (VAS), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS)-erythrocyte sedimentation rate (ESR), and ASDAS-C-reactive protein (CRP) were used as the indicators of clinical activity. Magnetic resonance imaging of the sacroiliac joint was performed and the Spondyloarthritis Research Consortium of Canada (SPARCC) score was evaluated by a radiologist who was blinded to the clinical and laboratory parameters of the patients. Results: The mean duration of symptom onset was 9.3±7.7 years, and the mean duration of diagnosis was 3.6±2.8 years. Human leukocyte antigen (HLA)-B27 was positive in 16 (50%) patients. There was no correlation between the SPARCC score and VAS, BASDAI, MASES, BASFI, ASDAS-CRP, ASDAS-ESR, ESR, and CRP values (p>0.05). In the HLA-B27 subgroup analyses, a statistically significant correlation was found between HLA-B27-negative patients and SPARCC score (r=0.639, p=0.008). Conclusion: No relationship was found between other clinical disease parameters and sacroiliac joint imaging findings, except for the relationship between the SPARCC and BASDAI in HLA-B27- negative patients with axSpA.

The role of endocannabinoid system and TRPV1 receptors in the antidepressant and anxiolytic effects of dipyrone in chronic unpredictable mild stress in mice.

Although dipyrone is a widely used analgesic and antipyretic, its mechanism of action is not fully clarified. Recent studies have drawn attention to its central effects and its relationship with the endocannabinoid system. The endocannabinoid system plays important roles in processes such as anxiety, depression, fear, and learning-memory. In this study, we aimed to investigate whether endocannabinoid levels change in the amygdala in chronic unpredictable mild stress model in mice and whether cannabinoid and TRPV1 receptors mediate antidepressant and anxiolytic effects of dipyrone. Mice were submitted to chronic unpredictable mild stress protocol of 6-weeks, then behavioral test were performed. In the first part of the study, dipyrone was injected at doses of 150, 300, and 600 mg/kg (i.p.) during behavioral tests. In the second part, the CB1 antagonist AM 251 (1 mg/kg, i.p.), the CB2 antagonist AM630 (1 mg/kg, i.p.), and the TRPV1 antagonist capsazepine (3 mg/kg, i.p.) were administered alone or in combination with 300 mg/kg dipyrone to observe if these receptors mediate dipyrone effects. Endocannabinoid and N-acylethanolamines levels were measured by LC-MS/MS in amygdala. Our results showed that there were no changes in AEA, 2-AG, PEA, OAE levels in the amygdala in mice exposed to chronic unpredictable mild stress model; dipyrone exerted antidepressant and anxiolytic effects at doses of 300 and 600 mg/kg; its anxiolytic effect appears to be mediated via CB1 receptors, whereas TRPV1 receptors seems to mediate its antidepressant action.

Shear bond strength of a self-adhesive resin cement to dentin surface treated with Nd:YAG and femtosecond lasers.

This study aims to evaluate the effect of Nd:YAG and femtosecond lasers irradiation on the shear bond strength (SBS) of a self-adhesive resin cement to the human dentin surface. One hundred extracted third molar teeth were randomly divided into 10 experimental groups according to dentin surface treatments; with and without the bonding agent, Nd:YAG 302 J/cm2 and 440 J/cm2, femtosecond 4 J/cm2 and 7 J/cm2, and control groups were prepared. After surface treatments, a self-adhesive resin cement was luted by using a bonding jig (Ultradent Products Inc.). The specimens were then subjected to shear test at a crosshead speed of 0.5 mm/min, and failure loads were recorded as megapascal (MPa). Two-way analysis of variance and Tukey HSD tests were performed (p Ë‚ 0.05). Representative specimens from each experimental subgroup were examined by means of SEM. The highest SBS values were obtained in Group 302 J/cm2 Nd:YAG with bonding agent, and there is no statistical difference between Group 440 J/cm2 Nd:YAG with bonding and Group 7 J/cm2 femtosecond with bonding (p > 0.05). The lowest SBS values were observed in Group control without bonding agent. Nd:YAG and femtosecond laser treatments improved the adhesion between the dentin surface and the self-adhesive resin cement.