Mean Ra Research Articles

Influence of thermal and pH cycles on surface characteristics lithium disilicate glass-ceramic dental crowns milled with CAD/CAM process

PurposeThe paper aims to evaluate the influence of thermo-chemical cycles of oral fluids on the surface attributes (roughness and microhardness) of lithium disilicate glass-ceramic (LDC) crown restorations manufactured with CAD/CAM technology.Design/methodology/approachThere have been 24 LDC crowns manufactured using the CAD/CAM process for their respective preparation dies ply methyl methacrylate (PMMA) of mandibular left second premolar tooth (n = 8 each group). The standard procedure was used to glaze 16 crown samples (Groups 2 and 3).Samples of Group 3 were aged with thermal (563°C and 5563°C) and pH (2–14) cycles. All 24 samples were tested with a Profilometer and a Vicker hardness tester was used for their surface roughness and hardness measurement, respectively.FindingsIn statistical examination on SPSS Statistics 20 (IBM) software, of surface roughness values (Ra) and Vicker hardness values from different groups, Tukey HSD test was executed in one-way ANOVA (a = 0.05). The means Ra for groups were accordingly Group 3 > Group1 > Group 2 (p < 0.001). Similarly, micro-hardness was in order of Group 2 > Group 1 > Group 3 (p < 0.001).Research limitations/implicationsThe research work does not have any limitations.Originality/valueSurrounding temperature and pH significantly impact the surface characteristics of lithium disilicate crown restoration. The study also reveals the inverse relationship between surface roughness and surface hardness parameters. The observed results and facts revealed well in agreement with the past research studies.

Study of the Influence of the Different Parameters of the Atmospheric DBD Treatment on the Surface Roughness and the Electric Potential Distribution Generated After the Tribocharging of Polypropylene

Square plates of polypropylene (PP), dimensions 100 mm × 100 mm × 4.5 mm, were treated by atmospheric dielectric barrier discharge (DBD) generated between two disk-type electrodes (Ø 75 mm), energized from an ac amplifier 30 kV, 20 mA. The study aimed at evaluating the factors that affect the roughness and the triboelectric behavior of the plasma-treated samples. The alteration of surface aspect after each treatment was clearly visible with the naked eye and the changes were confirmed by measurements carried out with a portable roughness meter (Surftest SJ-210) and a digital microscope (Keyence VHX-7000). The roughness of the PP samples increased from an initial arithmetic mean Ra = 0.06 μm (±0.01 μm) and standard deviation Rq = 0.08 μm (±0.01 μm) to Ra = 0.22 μm (±0.03 μm) and Rq = 0.25 μm (±0.03 μm), respectively. These increases were highly dependent on the air gap distance (10.5-13.5 mm), the treatment time (5-20 min), and the configuration of the DBD cell, i.e., the number (one or two) and the thickness (4-5 mm) of the glass dielectric barriers. Untreated and DBD-treated samples were tribocharged in a linear tribometer, to evaluate the effect of the cold plasma treatment on the electric potential generated on the polymer surface by the triboelectric effect. The electric potential measured by a noncontact electrostatic voltmeter (Trek, 341B) was higher and better distributed over the surface of the plasma-treated samples.

Surface roughness and gloss of polished nanofilled and nanohybrid resin composites

Background/purposeThere is limited literature on the polishability of new launched nanofilled and nanohybrid. The aim of this study is to evaluate the polishability of nanofilled and nanohybrid composites by measuring surface roughness and gloss values and explore the surface qualities of composite before and after polishing in vitro.Materials and methodsOne nanofilled resin composite, two nanohybrid resin composites and one microhybrid resin composite were selected. All specimens were light cured against celluloid matrix strips. Then surface roughness(Ra) and gloss(GU) values were tested as negative control. Specimens were roughened with a 600-grit silicon carbide paper for 30 s to serve as positive control and then polished with Sof-Lex polishing disk system. Mean Ra and GU values of each step were measured with a profilometer and a small-area glossmeter. The surface qualities were observed by scanning electron microscope.ResultsRa values of polished surfaces were significantly higher than negative control and lower than positive control(P < 0.05). All materials showed no significant difference on Ra values after polishing(P > 0.05). GU values of polished surfaces were significantly lower than negative control and higher than positive control(P < 0.05). After polishing the microhybrid resin composite showed lower GU values than nanofilled and nanohybrid resin composite groups. The SEM images showed surface textures and irregularities were corresponded to the results of surface roughness and gloss.ConclusionNo significant differences were noted on surface roughness among nanofilled, nanohybrid, and microhybrid composites after polishing with Sof-Lex disc system. Microhybrid composite presented lower gloss values than nanofilled and nanohybrid resin composites.

Influence of the magnetic field on the structural characteristics of granular CoxAg100-x thin film alloys

ABSTRACT We investigated structural-phase state, magnetic and magnetoresistive properties in as-deposited CoxAg100-x thin film alloys with a thickness of 35 nm as a function of composition (20 ≤ x ≤ 80 at.%). The aim of this work was to obtain a granular thin film alloy CoxAg100-x with the maximum amplitude of the giant magnetoresistance (GMR) and study of the magnetic field effect on structural characteristics of its surface. Studies of the effect of the magnetic field on the structural characteristics of the surface of the granular thin film alloy Co39Ag61, that characterized by the highest amplitude of GMR at room temperature, were performed. The GMR value for this sample was 14.7 % in transverse and 13.6 % in longitudinal measurement geometries under the magnetic field Bmax = 1.5 T. The application of the magnetic field led to a decrease in arithmetic mean Ra and the root mean square Rq values of the surface roughness, as well as the structural entropy of the system. At the first application of the magnetic field, the greatest decrease in the roughness of Ra by 19 % and Rq by 16 %, respectively, was observed. These changes persisted with increasing field strength up to B = 0.1 T. During the relaxation process (18 hours after the field was switched off), the structural characteristics of the sample were permanent.

Systematic review and meta-analysis of the risk of rheumatoid arthritis-associated interstitial lung disease related to anti-cyclic citrullinated peptide (CCP) antibody

ObjectiveTo clarify the risk of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) related to anti-cyclic citrullinated peptide (CCP) antibody.Eligibility criteriaPatients with RA with and without ILD were eligible. The primary outcome...

Right atrial strain by speckle-tracking echocardiography as a prognostic predictor in a pulmonary hypertension cohort

Abstract Funding Acknowledgements Type of funding sources: None. Background Right atrial (RA) strain is as a promising technique for assessment of RA function and several studies have suggested it is a powerful prognostic marker in pulmonary hypertension (PH) patients (pts). Our aim was to assess the prognostic power of RA strain in Pulmonary Arterial Hypertension (PAH) and Chronic Thromboembolic Pulmonary Hypertension (CTEPH) pts. Methods Pts with PH were prospectively studied and several clinical/demographic/echocardiographic were retrieved as well as data from six-minute walk test (6MWT) and brain natriuretic peptide (BNP). Correlation between RA strain and other variables was tested with Pearson"s correlation analysis. Regression and survival analysis were performed to assess the combined endpoint of all-cause mortality or hospitalization in the first follow-up year (MH1). Results A total of 51 PH pts (mean age 54 ± 46 years, 33.3% male, baseline BNP of 342.4 ± 439.9pg/mL and baseline pulmonary artery systolic pressure – PASP - of 78 ± 26mmHg), of which 64.7% had PAH and 35.3% presented CTEPH. 19 ots (37.3%) met the primary endpoint. The mean RA strain was -21.9 ± -4.9%, with no significant difference between groups (-23.4% vs -17.8%, p = 0.150), however male pts had a significantly lower RA strain (-15.9% vs -25.1%, p = 0.014). There was a statistically significant (p &amp;lt; 0.05) correlation between RA strain and age (r = -0.287), indexed RA area (r = -0.539), index RA volume (r = -0.522) and right ventricular strain (r = -0.453). There was no correlation between RA strain and BNP value (p = 0.150), 6MWT distance (p = 0.145) or PASP (p = 0.072). RA strain was a predictor of MH1 (OR = 0.94, 95% CI: 0.894-0.998, p = 0.048). Pts who met the primary endpoint had a significantly worse RA strain (-17.0 vs -24.6%, p = 0.032). Those with a RA strain worse than -19% presented a significantly lower survival free of events during the first follow-up year (log rank p = 0.022). Conclusion RA strain is a powerful predictor of adverse events in a PH population and should be systematically assessed in order to improve risk stratification. Abstract Figure.

In Vitro Effects of Fluoride, Hydroxyapatite, and Bromelain-Containing Toothpaste Types on Surface Roughness of Different Restorative Materials

Aim: To examine the effects of fluoride, hydroxyapatite, and bromelain-containing toothpaste types on the surface roughness of nanohybrid, nanofilled, flowable, and bulk-fill composites; conventional, light-curing, and low-viscosity glass ionomers; and compomers. Materials and Methods: A total of 160 specimens were fabricated using nanohybrid, nanofilled, flowable, and bulk-fill composites; conventional, light-curing, and low-viscosity glass ionomers; and compomers. Each material group was divided into four subgroups ( n = 5) as follows: Control (C), fluoride toothpaste (FT), bromelain toothpaste (BT), and hydroxyapatite toothpaste (HT). Surface roughness values of all specimens were examined using an optical profilometer and a scanning electron microscope at 500, 1,000, and 3,500 magnifications. Results: The highest average roughness value (Ra; µm) was obtained from the conventional glass ionomer material ( P &lt; .001). While the mean Ra value was 0.155±0.116 µm at baseline, it was 0.262±0.203 µm in the fluoride group, 0.237±0.192 µm in the hydroxyapatite group, 0.260±0.293 µm in the bromelain group, and 0.198± 0.187 µm in the control group ( P &lt; .001). Conclusion: We have found that brushing with various types of toothpaste containing fluoride, bromelain, and hydroxyapatite may not result in obtaining different surface roughness values from different types of restorative materials. Differences in surface roughness values of restorative materials may be found at different magnifications under scanning electron microscope.

Effect of 2% Sodium Hypochlorite, Denture Cleansing Tablet and Tea on the Discolouration and Surface Roughness on Two Types of Denture Acrylic Resin: An In vitro Study

Introduction: Denture cleansers affect the physical properties of denture materials, such as colour and surface roughness. Using denture cleanser with the least side effects in the best choice. There are only limited studies available evaluating the effects of denture cleaners in association with staining solutions on acrylic resins. Aim: This study aimed to investigate the effect of denture cleansers in association with staining solution (tea), on the denture colour and surface roughness. Materials and Methods: In this in vitro study conducted at Dental Faculty of Tabriz Medical University of Science, Tabriz, East Azarbaijan, Iran, from May 2018 to June 2019, 56 samples each were prepared from two types of acrylic resin (Acrosun and TDV Dental). The 2% Sodium Hypochlorite (NaOCl) solution and professional cleansing tablets were used as detergents, and tea was used as a dye. The samples were assigned to seven groups (n=8 samples in each group) for each type of acrylic used. The study groups consisted of group 1 (NaOCl solution for 10 minutes), group 2 (NaOCl solution for 8 hours), group 3 (cleansing tablet solution for 8 hours), group 4 (tea solution for 2 hours), group 5 (first tea solution and then NaOCl), group 6 (tea solution and then cleansing tablets) and group 7 (distilled water). Surface roughness was analysed with Ra and Rz indices, and colour changes were evaluated with CIELAB index before and after the experiment, and the data were recorded. Finally, data analysis was performed with Statistical Package for the Social Sciences (SPSS) version 21.0. The p-value less than 0.05 was considered as significant. Results: The results of 112 disk-shaped samples prepared showed that in all the study groups, the colour change of Acrosun acrylic resin was more severe compared to that in TDV dental acrylic resin, which was significant only in groups 1, 2, and 5 (p-value &lt;0.05). Comparison of the mean Ra index showed that surface roughness was the maximum and minimum in groups 6 and 1, respectively, compared to other groups. A comparison of the effect of different cleaning methods on acrylic resin surface roughness showed that the surface roughness indices of Ra and Rz were not significantly different in any of the groups (p-value &gt;0.05). Conclusion: The two types of acrylic resin did not differ significantly in surface roughness after the experiments. However, the TDV dental acrylic resin was superior in terms of colour stability.

Comparison of Different Finishing-Polishing Systems on Surface Roughness of Nanofilled Composite Resin

Aim: This in vitro study was conducted to evaluate the effectiveness of different finishing and polishingsystems on the surface roughness of nanofilled (Z350XT) composite resin.Materials and Methods: A total of 60 disc-shaped samples were prepared in composite resin usingstandardized cylindrical metal mold (10 mm in diameter and 2 mm thick). The specimens were randomlydivided into six groups (n= 10): Group 1- Mylar strip, Group 2- Sof-Lex polishing system, Group 3- SuperSnap polishing system, Group 4- OptiDisc polishing system, Group 5- Opti1Step polishing system andGroup 6- OneGloss polishing system. The average surface roughness (Ra) of each specimen was measuredthree times and the mean Ra values were determined using a surface profilometer.Results: According to the one-way analysis of variance, surface roughness was in the following order:Mylar strip < Super Snap polishing system < OptiDisc polishing system < Opti1Step polishing system <SofLex polishing system < OneGloss polishing system. This difference in surface roughness was statisticallysignificant (P < 0.05) in all the six experimental groups.Conclusion: Composite surface roughness depends on the composition, number of steps and flexibility ofthe finishing and polishing system used.

Impact of dietary acids on the surface roughness and morphology of composite resins.

This in vitro study was performed to evaluate the surface roughness (Ra) and morphology by scanning electron microscopy (SEM) of composite resins that had been stored in acidic solutions typical of those present in the diet. Three composite resins (4 Seasons, Z250, and P90) were selected and divided into three groups (n = 7) according to the solutions tested: G1: distilled water; G2, Coca-cola, and G3: orange juice. The Ra test was repeated after immersion periods of 15, 90, and 180 days. The mean Ra values were subjected to LS means analysis and the Tukey-Kramer (P < 0.05). One test specimen of each composite resin was selected for SEM analysis after each period. The Ra data indicated that P90 had the lowest Ra values. 4 Seasons and Z250 had statistically similar roughness values for all the solutions and evaluation periods. With the exception of 180-day immersion in Coca-cola, 4 Seasons showed significantly higher values than Z250. SEM analysis showed that P90 was the composite resin most resistant to the actions of all acid solutions for the periods analyzed. Interaction between components of the solutions and the active components of other dietary items, as well as oral hygiene, may affect the chemical degradation of composite resins.

Accuracy of Physical Exam in Covid Era

IntroductionPhysical examination remains central to the management of heart failure patients. The assessment of volume status guides medical management and estimation of prognosis. Jugular venous pressure (JVP) estimation is the most important and accurate part of the physical examination in heart failure patients to assess volume status. Telemedicine visits are now a common place across the nation due to the current pandemic. In this unique situation we conducted a study to assess the accuracy of JVP estimation during a telemedicine visit.MethodsThis is a retrospective observational study. All the patients who were seen via telemedicine visit in the advanced heart failure, LVAD and transplant clinics were considered. The patients who underwent a right heart catheterization (RHC) within two weeks of the telemedicine clinic visit were included in the study. JVP measured by physical examination was obtained from chart review. Invasive hemodynamic data was obtained from RHC. JVP assessment was done via tele assessment with the patient in sitting position. For the purpose of this study JVP on examination was estimated by the clinician as either a numerical number or by distance in relation to the clavicle and jaw. Majority of the patients were male (n = 10) and had a mean age of 57 years. Mean BMI of the patients was 30. Eight of the eleven were post heart transplant patients. Two patients had a left ventricular assist device (Heartmate II and HVAD devices) placed as Destination therapy.ResultsFrom April 1st 2020 to May 21st 2020 twenty patients were identified who underwent RHC two weeks after their telemedicine visit. Of these eleven patients had JVP documented at the time of telemedicine visit and were included in the study. Seven patients had JVD not detectable above the level of clavicle on examination. 85% (n = 6) of these patients had mean RA pressure less than 7 mm Hg on RHC. One patient had mean RA pressure 8 mm Hg. Two patients were documented to have a JVP of 10 cm H2O. Both these patients had JVP of 8 mm Hg on RHC. Two patients were documented to have JVP of more than 10 cm H20 and both these patients had mean RA pressure more than or equal to 12 mm Hg on RHC.90% (n = 10) of patients had accurate assessment of right-sided filling pressures by examination via tele visit.

English

The radical increase in consumption of acidic (sour) candies amongst children and teenagers is considered a significant public health concern. The purpose of this study was to evaluate the erosive potential of sour candy in comparison with their regular counterparts at different exposure times. Sixteen prepared tooth samples were randomly assigned into four groups, namely: sour candy (n=8), regular candy (n=8); each of these was prepared to have protected (unexposed) and exposed surfaces in respective candy solutions for 15 min and 2 h (n=4). An Atomic Force Microscope (AFM) was used to measure the surface roughness (Ra) between the exposed and unexposed enamel surfaces for each sample group. The mean Ra measured was used for statistical analysis whilst the elemental loss was assessed using Energy Dispersive Spectroscopy (EDX). The findings showed that sour candy significantly eroded the exposed enamel samples (P&lt;0.01). Overall, the samples exposed to the sour candy for 2 h had the highest eroded Ra values. The study suggests that frequent and long-time consumption of sour candies may pose a negative impact on the tooth as they are found to be highly erosive. Key words: Candy; erosion, tooth enamel, sour candy. &nbsp

Atomic Force Microscope Surface Roughness Analysis of Surface Treated Ceramics

AIM: The purpose of this study was to evaluate the surface roughness of two types of ceramic after different surface treatments using an atomic force microscope (AFM).&#x0D; MATERIALS AND METHODS: One hundred sixty disks were fabricated of the two types of ceramic eighty disks of lithium disilicate (LD) (IPS e. max computer-aided design [CAD]) and eighty disks of hybrid ceramic (VITA Suprinity pc). Disks were subdivided into four groups according to the surface treatment (n = 20). Eighty disks of (IPS e. max CAD) were subdivided into LD I: control (no treatment), LD II: Sandblasting (Al2O3, 50 μm particle size), LD III: Hydrofluoric acid etching, and LD IV: Tribochemical surface treatment. Eighty disks of (VITA Suprinity pc) were subdivided into HD I: control (no treatment), HD II: Sandblasting (Al2O3, 50 μm particle size), HD III: Hydrofluoric acid etching, and HD IV: Tribochemical surface treatment. Then, surface treated disks surface roughness was analyzed by AFM (ThermoMicroscope, Bruker, Santa Barbara, CA, USA). The results were analyzed using SPSS program software version 25. Statistical analysis was done by one-way ANOVA and Tukey’s post hoc test with significance level 0.05.&#x0D; RESULTS: Tribochemical surface treatment groups of both types of ceramic L.D IV (279 ± 147 nm) and H.D IV (269.8 ± 142.2 nm) had the highest mean Ra values followed by surface abrasion with Al2O3 50 μ; L.D II (265.5 ± 140 nm), H.D II (204.5 ± 107.7 nm), hydrofluoric acid etching then control groups.&#x0D; CONCLUSION: Different surface treatments increased surface roughness significantly for both types of ceramic.

Fatigue performance of adhesively luted glass or polycrystalline CAD-CAM monolithic crowns

Statement of problemData comparing the fatigue performance of adhesively luted glass or polycrystalline ceramic systems for computer-aided design and computer-aided manufacturing (CAD-CAM) are scarce. PurposeThe purpose of this in vitro study was to evaluate and compare the fatigue performance of monolithic crowns manufactured from glass or polycrystalline CAD-CAM ceramic systems adhesively luted to a dentin analog. Materials and MethodsFifty-four pairs of standardized preparations of dentin analog (NEMA Grade G10) and simplified ceramic crowns of 1.5-mm thickness were obtained with 3 ceramic materials: lithium disilicate (LD) glass-ceramic (IPS e.max CAD); zirconia-reinforced lithium silicate (ZLS) glass-ceramic (Vita Suprinity); and translucent yttrium fully stabilized polycrystalline zirconia (Trans YZ) (Prettau Anterior). The simplified crowns (n=15) were adhesively cemented onto the preparations and subjected to step-stress fatigue test (initial load of 400 N, 20 Hz, 10 000 cycles, followed by 100-N increment steps until failure). Collected data (fatigue failure load [FFL] and cycles for failure [CFF]) were submitted to survival analysis with the Kaplan-Meier and Mantel-Cox post hoc tests (α=.05) and to Weibull analysis (Weibull modulus and its respective 95% confidence interval). Failed crowns were submitted to fractography analysis. The surface characteristics of the internal surface (roughness, fractal dimension) of additional crowns were accessed, and the occlusal cement thickness obtained in each luted system was measured. ResultsTrans YZ crowns presented the highest values of FFL, CFF, and survival rates, followed by ZLS and LD (mean FFL: 1740 N>1187 N>987 N; mean CFF: 149 000>92 613>73 667). Weibull modulus and cement thickness were similar for all tested materials. LD presented the roughest internal surface, followed by ZLS (mean Ra: 226 nm>169 nm>93 nm). The LD and ZLS internal surfaces also showed higher fractal dimension, pointing to a more complex surface topography (mean fractal dimension: 2.242=2.238>2.147). ConclusionsCAD-CAM monolithic crowns of Trans YZ show the best fatigue performance. In addition, ZLS crowns also showed better performance than LD crowns.

Effect of Repeated Firings on the Color Change and Surface Roughness of Two All-ceramic Systems

Purpose: This study aimed to evaluate the effect of repeated firings on the color change and surface roughness of two all-ceramic systems. Materials and Methods: Forty disc shaped ceramic specimens ( 10 mm x 1 mm ) were fabricated from two commercially available all-ceramic system (IPS E.max press, Ivoclar-Vivadent, Schaan, Liechtenstien, Germany and zirconia Nacera Pearl, DOCERAM Medical Ceramics, Germany) (N=20). Color measurement of the specimens was made using Reflective spectrophotometer and surface roughness (Ra) was measured using USB digital profile guage, (Elcometer 224/2, Elcometer Instruments, Great Britain) after 1, 3, 5 and 7 repeated firing. Results: The mean color change (ΔE) was clinically acceptable for both types of ceramics. As regards the effect of ceramic material on (ΔE), e.max showed statistically significantly higher mean color change (ΔE) than Zirconia. As regards the effect of repeated firings on (ΔE), 7 repeated firings showed statistically significantly higher mean (ΔE) than 5 repeated firings which in turn showed statistically significantly higher mean (ΔE) than 3 repeated firings. Surface roughness measurements showed that there were significant difference between E.max and zirconia and that zirconia showed higher mean (Ra) than e.max. Also the results of the current study showed that there were a significant difference between mean (Ra) and numbers of firing as roughness decrease with increasing the number of firing. Conclusions: Repeated firings negatively affecting the color change and surface roughness and should be minimized as possible.

Alterations in Surface Roughness and Chemical Characteristics of Sandblasted and Acid-Etched Titanium Implants after Irradiation with Different Diode Lasers

The purpose of this study was to evaluate the effects of diode laser irradiation with different wavelengths on the surface roughness (Ra) and chemical composition of sandblasted and acid-etched (SLA) titanium implants. Three types of diode lasers with different wavelengths were irradiated on the titanium implants at output powers of 1.0, 2.0, and 3.0 W. The mean Ra values for all spots were measured using a scanning probe microscope. Analysis of variance tests were performed to verify the differences in the Ra between groups according to the type of lasers or power out (α = 0.05). For analyzing chemical composition, atomic and weight percent ratios of titanium, oxygen, and carbon were measured using energy-dispersive spectrometry (EDS). The mean Ra of titanium disc was higher in the 3.0-W output than in 1.0-W or 2.0-W output, but there was no statistically significant difference (p &gt; 0.05). In EDS analysis, it was difficult to find a clear difference in the titanium, oxygen, and carbon element ratios between the laser-irradiated and nonirradiated groups. The irradiation of diode laser with 1.0, 2.0, and 3.0 W output for 15 s decontaminated the SLA titanium surface without damage. However, additional clinical trials will be needed to verify the results of the present study.

Cumulative patient-based disease activity monitoring in rheumatoid arthritis – predicts sustained remission, flare and treatment escalation

ObjectivePatient-based Disease Activity Score 2 (PDAS2) had been developed for RA patients to self-assess and record disease activity in between clinic visits. This study explored the clinical utility of time-integrated cumulative PDAS2 (cPDAS2) on predicting sustained remission or low disease activity state (LDAS), flare and treatment escalation. MethodsWe recruited 100 patients to record PDAS2 at home fortnightly between two consecutive clinic visits. Rheumatologists adjusted treatment according to disease activity recorded during clinic consultation while blinded to home PDAS2 scores. cPDAS2 calculated from the area-under-curve of all PDAS2 scores were compared with disease activities at both visits. cPDAS2 and ΔcPDAS2 (change from PDAS2 at the first visit) were tested to determine their ability to predict ACR/EULAR remission, SDAI flare-up (from remission/LDAS to moderate/high disease activity) and treatment escalation. Optimal cut-points were determined by Receiver Operator Characteristic curve. ResultsMean age of the patients was 59 years, mean RA duration 14 years, 90% were female, 71% seropositive and 64% in remission/LDAS. The home PDAS2 completion rate was 92%. PDAS2 scores were done 7.5 times every 15 days over a 16-week follow-up (all medians). The sensitivity of cPDAS2 in predicting Boolean/SDAI remission at two visits, DAS28, SDAI and CDAI remission or LDAS were 93%, 84%, 73% and 80% respectively. cPDAS2 ≥ 0.29 predicted flare (P = 0.04), with specificity 79% and negative predicting value (NPV) 88%. Rheumatologists' decision to escalate treatment was predicted by (cPDAS2 ≥ 4.33 and ΔcPDAS2 ≥ 0.059) (P = 0.007) with specificity 88% and NPV 89%, and (cPDAS2 ≥ 4.33 or ΔcPDAS2 ≥ 0.059) (P = 0.02) with both sensitivity and NPV 100%. ConclusionPDAS2 monitoring at home is feasible. cPDAS2 is useful to predict flare and treatment escalation.

Effect of In-Office Bleaching Techniques and Topical Fluoride Application on Color and Surface Roughness of Two Types of Dental Ceramics (In-Vitro Study)

Objective: This in-Vitro study was to assess the effect of 2 bleaching techniques & topical Fl application on color & Ra of 2 types of CAD/CAM ceramics. Materials&methods:40 discs of 2 CAD/CAM ceramics were used IPS e.max(E)&Suprinity(S). Baseline measurements for color & Ra were taken using spectrophotometer &AFM. The specimens were divided into 2subgroups according to the bleaching agent used Zoom(Z) & Opalescence Boost 40%(O). 2 measurements of color & Ra were done: immediately after bleaching (I)& after 1week from the last bleaching session(D). Specimens were exposed to APF application & final measurements of color & Ra values were done. Results: Bleaching had a statistically significant effect on mean ∆E of all groups. No significant difference on mean ∆E of the 2ceramic materials. O showed higher statistically significant difference in ∆E than Z. S showed higher statistically significant difference in ∆E than E. Ceramic type & bleaching agents had a statistically significant effect on mean Ra. In I, SZ showed the highest mean Ra value while in D&F,EO showed the highest mean Ra. After F, Ra of ceramic materials demonstrated higher values than bleaching only. There was a +ve correlation between ∆E&Ra. Conclusions: The influence of in-office bleaching agents on color was material dependent. The changes in color & Ra were time dependent. Fl application following bleaching of ceramic materials showed higher color & Ra changes than bleaching only in groups. Recommendation: The ceramic restoration should be protected before bleaching&/or Fl application to avoid esthetic deterioration.

O08 Development and validation of a new tool to assess inflammatory foot disease activity in RA: the Rheumatoid Arthritis Foot Disease Activity Index

Abstract Background Rheumatoid arthritis (RA) commonly affects the feet, resulting in pain, walking difficulties, and disability. Omission of foot joints from the disease activity score-28 (DAS-28) may lead to underestimation of foot disease and suboptimal medical and non-medical management. Therefore, the overall objective of this study is to evaluate the measurement properties of the Rheumatoid Arthritis Foot Disease Activity Index-5 (RADAI-F5), a newly developed 5-item (0-10 numerical rating scale) patient-reported outcome measure (PROM) with a summary score (0-10) for measuring foot disease activity in people with RA. Methods Participants with RA recruited from NHS rheumatology outpatient clinics completed the RADAI-F5, a self-modified Rheumatoid Arthritis Disease Activity Index (mRADAI-5) which is a self-reported measure of global disease activity, the Foot function index (FFI), Foot Impact Scale impairment/footwear (FIS-IF) and activity/participation (FIS-AP) subscales. DAS-28 was also recorded for each participant whenever possible. Participants completed RADAI-F5 again at 1 week to allow evaluation of 1-week reproducibility. Construct validity was evaluated using Spearman’s rho to test a priori hypotheses for expected strength of associations between the RADAI-F5 and the alternative disease activity and foot-related disability scales at baseline. Internal consistency was evaluated using Cronbach’s alpha. One-week reproducibility was evaluated using the intraclass correlation coefficient (ICC), 90% smallest detectable change (SDC90), and 95% limits of agreement (LOA). Content validity was evaluated using 5-point Likert scales for readability and relevance. Results Of 142 respondents, 103 were female and 36 were males with a mean (SD) age of 55 years (12.5) and mean (SD) RA disease duration of 39 months (70.4). Mean (SD, range) RADAI-F5 scores for the sample were 5.02 (2.47, 9.2). Associations were largely consistent with a priori hypotheses for construct validity. Strong associations were observed between the RADAI-F5 and MRADAI-5 (0.789, CI 0.73-0.85), the FFI (0.713, CI 0.62-0.79) and FIS-IS (0.695, CI 0.66-0.82) (p &amp;lt; 0.001). Moderate associations were observed with the FFI-AP (0.478, p &amp;lt; 0.001, CI 0.37-0.63). A weak association was observed between the RADAI-F5 and the DAS-28 (0.379, p &amp;lt; 0.001, CI 0.26-0.57). The RADAI-F5 demonstrated high internal consistency (Cronbach’s Alpha=0.82), and floor and ceiling effects were both absent. The RADAI-F5 demonstrated good reproducibility (ICC=0.868, p &amp;lt; 0.001, CI 0.80-0.91) and the value for SDC90 was 2.26. The upper and lower bounds for 95% LOA were -2.57 to 2.80, with 97% of scores observed within these bounds. Content validity was confirmed with 82% and 84% of participants rating the instrument as relevant and easy to understand respectively. The median time for completion was 5 minutes. Conclusion The RADAI-F5 is a highly valid and reliable PROM for measuring foot disease activity in RA patients. Furthermore, the RADAI-F5 appears to be feasible for use in clinical practice and can be used as an adjunct to the DAS28 to measure foot disease activity. Disclosures A. Hoque: Grants/research support; Stipend from Versus Arthritis to complete the Versus Arthritis MSK internship 2019 at Glasgow Caledonian University.

The effect of repressing on surface topography and microshear bond strength of two pressable ceramics

Objective: This in-vitro study was carried out to investigate the effect of repressing on surface topography and micro-shear bond strength of Lithium di-silicate (IPS e.max press) and zirconia reinforced lithium di-silicate (Celtra press). Materials and Methods: Two commercially available glass ceramic materials were used in this study; IPS e.max press (Ivoclar, vivadent) and Celtra press (Dentsply, Sirona). The two materials were used to fabricate disc samples. A total of thirty two ceramic disc specimens with 1.2 mm height and 12 mm diameter were constructed. The flat round disc samples for each material(n=16) were randomly divided into two equal groups: group I: Pressed ceramic discs and group II: Repressed ceramic discs (n=8).The disc samples were further subdivided into two equal subgroups according to the type of cement used (n=4): subgroup A: samples were cemented with Multilink automixed ,self-adhesive resin cement. Subgroup B: samples were cemented with Rely X-unicem 2 automixed, self-adhesive resin cement. Fabrication of disc samples for the two tested materials, surface treatment and cementation procedures were done for both types of cements according to manufacturer instructions. Results: For IPS e.max or Celtra press; there was no statistically significant difference between mean Ra value (µm) of press and repress conditions. IPS e.max showed statistically significantly higher mean micro-shear bond strength than Celtra press. Conclusions: Pressing of glass ceramics for one injection is recommended. Repressing of glass ceramics improved surface topography but compromises the bond strength.