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Objectives: To compare marginal gap width and depth with different cementation systems, excess removal, and after polishing. Method and materials: In total, 80 composite crowns were milled, divided into ten groups, and cemented on identical artificial teeth. Eight crowns per group were fixed with (i) zinc phosphate cement (ZnOPh), (ii) glass-ionomer cement (GIC), (iii) resin-reinforced glass-ionomer cement (GIC mod), (iv) dual-curing adhesive composite (Comp dual), or (v) dual-curing self-adhesive composite (Comp SE dual). Excess removal was performed with a scaler after brief light-cure (tack-cure), final light-cure, during rubber or gel phase or by wiping with foam pellet. Curing was completed in chemical, dark cure, or light-curing modus. The specimens were polished and stored in water (37°C). The margins were digitized using a 3D laser-scanning microscope (VK-X100 series, Keyence). The width and the depth of the marginal gap were measured at 10 points between the crown margin and the preparation margin. Results: The width after excess removal varied between 65.1 ± 15.7 µm (Comp dual, wipe, with polishing) and 208.6 ± 266.7 µm (Comp SE dual, dark cure, without polishing). The depth varied between 29.8 ± 22.2 µm (Comp dual, wipe, with polishing) and 89.5 ± 45.2 µm (Comp SE dual, dark cure, without polishing). The impact on gap width and depth was detected for fixation material, excess removal, and polishing. Conclusion: The gap depth and width depend on the luting material and the mode of access removal. Polishing can improve the gap quality, especially for GIC and resin-based systems. [ABSTRACT FROM AUTHOR]

Phase separation was observed in silica glass following low‐temperature heat treatment in high water vapor pressure through the formation of bubbles. Although the 6 day diffusion treatment in saturated water vapor pressure at 250°C does not normally cause phase separation, the reactive fracture surface and subsurface damage caused by polishing with cerium oxide (CeO2) allowed for an increase in water absorption during treatment and heterogeneous nucleation of the bubbles at damaged sites. The sub‐surface damage, characteristic of blunt contact damage, was only revealed when the polished sample was etched. The formation of bubbles and polishing damage were observed in two silica glasses—one containing chlorine impurities and the other containing OH impurities. Raman spectra collected after fracture or polishing and water diffusion treatment demonstrated an increase in the abundance of –OH species including silanol (SiOH) groups and an evolution in the glass structure in the bubble regions compared with the bubble‐free regions. These results indicate an increase in the reactivity between water and glass fracture surfaces relative to the bulk. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusion Clinical Significance The purpose of this in vitro study was to evaluate the effect of staining, glazing, and polishing on the survival probability of monolithic crowns manufactured with preshaded stabilized zirconia with 5 mol% of yttrium oxide (5Y‐TZP).Monolithic crowns in the shape of an upper canine (1.5 mm of thickness) were manufactured by CAD/CAM, adhesively cemented on metallic foundation, and divided into 6 groups (n = 21): C (control), S (staining), G (glazing), P (polishing), SG (staining and glazing), and SP (staining and polishing). The survival probability was determined by step‐stress accelerated life testing with a load applied to the palatine concavity of the crown. First, the specimens were subjected to a single‐load to fracture test (SLF) and next to the fatigue test (5 Hz, thermocycling immersed in water varying 5–55°C), including the light (n = 9), moderate (n = 6), and aggressive (n = 3) loading profiles (load ranged between 20% and 60% of SLF). The survival probability was calculated considering the cycles for failure (CFF) and fatigue failure load (FFL) and illustrated using a Kaplan–Meier graph. The comparison among groups was performed using a Log‐Rank test (α = 0.05).The mean value of SLF was 586.7 N. There was no difference among groups in survival probability, considering CFF and FFL.Staining, glazing, and polishing can be performed safely without damaging the mechanical behavior of 5Y‐TZP monolithic crowns.Staining is used to characterize and improve the esthetic of zirconia monolithic crowns. It can be used to reproduce the color gradient in the cervical region of the crown and pigmented grooves. This study showed that staining, glazing, and polishing did not affect the survival probability and the use of finishing procedures (glazing or polishing) after staining did not improve the survival probability of zirconia monolithic crowns. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the effect of toothbrushing cycles on surface roughness (Ra), gloss (GU), and morphology of two zirconia finishing and polishing protocols. Materials and Methods: An ultra‐translucent zirconia disc was sectioned into rectangular plates (12 mm × 7 mm × 3 mm) and divided into two groups according to the polishing and finishing system used (diamond rubber abrasive/DRA or glazing/GLA). Bovine enamel (BEN) plates with the same dimensions were used as a Control. Specimens of zirconia and enamel were analyzed for Ra and GU (n = 11) and surface morphology by scanning electron microscopy (n = 3) before toothbrushing (baseline) and after 15,000 and 30,000 toothbrushing cycles. Ra and GU data were analyzed by ANOVA two‐way and post‐hoc Tukey's test (α = 0.05), while the surface morphology was analyzed qualitatively. Results: The Ra decreased significantly after 30,000 toothbrushing cycles for DRA and GLA zirconia ceramics. DRA showed a higher GU at the baseline, after 15,000 and 30,000 toothbrushing cycles than GLA and BEN. Toothbrushing polished the zirconia, creating a smooth surface, while no changes were observed for BEN. Conclusions: The increase in toothbrushing cycles (30,000) changed the surface roughness of DRA and GLA zirconia ceramics. DRA zirconia presented the highest GU, which did not change with toothbrushing. [ABSTRACT FROM AUTHOR]

Defects, such as scratches, cleavage fracture, and cleavage pit, occur during surface processing and affect the surface integrity of β-Ga2O3(100) substrates. This study analyzes the effects of polishing materials (polyurethane, lead, and copper) and substrate surface temperatures (25, 10, and 0 ℃) on the polishing results to overcome the effects of such defects on the substrates. Vickers indentation tests were used to detect the effects of the material and surface temperature on the hardness of the disc and substrate, respectively. Machining was verified by conducting ball-disk friction wear and polishing experiments. The experimental results indicate that the material of the polished optical disc significantly affected β-Ga2O3(100) during surface processing. The higher the hardness of the polished optical disc, the greater the material removal rate (MRR) of the substrate surface, and more serious the surface cleavage phenomenon. A lead disc with lower hardness could be used to process β-Ga2O3(100) for realizing a higher MRR, thereby effectively avoiding cleavage fractures and obtaining a surface roughness (Ra) and scratch depth of 3.4 nm and 18 nm, respectively. The hardness and mechanical strength of the substrate could be enhanced at low temperatures, and the indentation depth would become smaller under the action of external forces, effectively inhibiting the formation of scratches and pits on the surface of the substrate during polishing. After polishing the substrate at 0 ℃, the Ra, scratch depth, and total number of cleavage pits were 2.2 nm, 14.3 nm, and 246 nm, respectively. Compared with 25℃, Polishing the substrate at 0 ℃ decreased the Ra, scratch depth, and number of cleavage pits by 35.3, 20.6, and 34.9%, respectively. At 0 ℃, the substrate effectively avoided cleavage fracture and inhibited scratch and pit formation, thereby significantly improving the polishing effect. [ABSTRACT FROM AUTHOR]

Esthetically pleasing temporary prostheses are often necessary for extended periods in a variety of clinical scenarios. Adjustments to the occlusion or margins are commonly needed before cementing the temporary prosthesis. Therefore, it is clinically necessary to repolish the rough surface to avoid biological and esthetic issues associated with rough surfaces. The purpose of this in vitro study was to assess and compare the impact of various polishing protocols on the surface roughness and color stability of three resin materials used for provisional crowns. A total of 150 specimens were fabricated from auto-polymerizing polymethyl methacrylate, bis-acryl composite, and Methyl methacrylate-LC resin using a stainless steel mold. Each material group was divided into five groups (n = 10) based on the applied surface treatment: positive control group (G1): no roughening or surface treatment, Negative control group (G2): acrylic bur-roughened surface without any polishing, the different surface treatment groups of silicon carbide and aluminum oxide stone polishing (G3), diamond-coated rubber twist (G4), and Surface Glaze (G5). An optical profilometer was used to assess the surface roughness of all samples. After undergoing 6000 cycles of thermocycling followed by immersion in a coffee solution for 15 days at 37 °C, color parameters were measured using a spectrophotometer both before and after a storage period to evaluate color differences. A two-way ANOVA test with α = 0.05 significance level was carried out to determine the impacts of both the materials utilized and the polishing protocol. Among the three types of resin examined, the bisacryl group exhibited superior surface quality in positive control groups, while PMMA resin demonstrated higher polishability. The diamond-coated rubber twits resulted in lower Ra values of 0.36 (0.01) µm, 0.52 (0.11) µm, and 0.28 (0.05) µm for PMMA, BAMA, and MMLC resins, respectively. The application of photo-polymerized surface glaze led to a plaque accumulation threshold of 0.2 µm across all resin groups. The greatest mean color change occurred in the negative control group, indicating a propensity for more staining on rougher surfaces. The Bisacryl resin exhibited higher ΔE values, whereas PMMA showed better color stability. The lowest ΔE values were found when the surface glaze was applied to all of the provisional crown resins. Untreated Bisacryl resin exhibited the lowest Ra values, while PMMA resins demonstrated superior surface morphology after polishing. PMMA provisional crown resins showed increased resistance to staining. The use of surface glaze enhanced both smoothness and color stability on the surfaces. [ABSTRACT FROM AUTHOR]

Kodo millet (Paspalum scrobiculatum) is a minor millet with high nutritional properties and exhibits exceptional drought-tolerance and insect-resistance. But, the processing of this millet offers considerable challenges due to the presence of thick layers of hull. Hydrothermal pre-treatment before milling has been reported to reduce grain fragility and nutrient loss. The current study aims to assess the effect of hydrothermal pre-treatments on the dehulling, polishing, and nutritional characteristics of kodo millet. The grains were subjected to soaking (4, 6 & 8 h), steaming (10 min), and drying (till 12% moisture content) before polishing. The hydrothermally treated grain is polished by applying shearing and abrasion forces sequentially. The number of shearing passes (2, 4 & 6), and abrasive polishing time (20, 40 & 60 s) has been varied. Multivariate analysis has also been carried out to understand the correlation between different process variables. Results demonstrated that the treatment conditions significantly affect the dehulling and polishing efficiencies and the nutritional compositions of the grain. The increase in shearing and abrasion action increased the dehulling and polishing efficiencies, respectively. The study's findings could potentially be installed to increase the dehulling and polishing efficiencies while reducing grain losses. [ABSTRACT FROM AUTHOR]

Objective This study aimed to test repolishing effect on color stability, translucency, and surface roughness of aged monochromatic dental composite in artificial saliva, tea, mouthwash, and coffee after 1 month, simulating 2.5 years of clinical use. Materials and Methods Omnichroma, a monochromatic dental composite, and Z250 XT a nanohybrid multishade dental composite were used in this study. Specimens (n = 80) from each dental composite were prepared to determine color stability, translucency parameter, and surface roughness after repolishing of aged specimens in artificial saliva, tea, mouthwash, and coffee for 1 month. Scanning electron microscope and laser scanning microscope were used to study surface topography after repolishing. Data was analyzed using analysis of variance, Scheffe test, and independent t -test. Results A significant difference between both dental composites after repolishing in terms of color stability and translucency parameter as that of Omnichroma was higher but sill color changes of Omnichroma were perceptible. There was no difference between both composites in regard to surface roughness after repolishing; however, values of both composites were above the accepted value of 0.2 µm and laser scanning microscope images confirmed these findings. Conclusions Repolishing did not enhance color and surface roughness of aged monochromatic dental composites. [ABSTRACT FROM AUTHOR]

The paper investigates the feasibility of plasma electrolytic treatment (PET) of 90CrSi tool steel to enhance hardness and wear resistance. The influence of electrophysical parameters of PET (polarity of the active electrode, chemical-thermal treatment, and polishing modes) on the composition, structure, morphology, and tribological properties of the surface was studied. Tribological tests were carried out under dry friction conditions according to the shaft-bushing scheme with fixation of the friction coefficient and temperature in the friction contact zone, measurements of surface microgeometry parameters, morphological analysis of friction tracks, and weight wear. The formation of a surface hardened to 1110–1120 HV due to the formation of quenched martensite is shown. Features of nitrogen diffusion during anodic PET and cathodic PET were revealed, and diffusion coefficients were calculated. The wear resistance of the surface of 90CrSi steel increased by 5–9 times after anodic PET followed by polishing, by 16 times after cathodic PET, and up to 32 times after subsequent polishing. It is shown that in all cases, the violation of frictional bonds occurs through the plastic displacement of the material, and the wear mechanism is fatigue wear during dry friction and plastic contact. [ABSTRACT FROM AUTHOR]

The BP-PSO was used to obtain the optimal process parameters of magnetorheological polishing quartz glass. Specifically, the orthogonal experiments investigated the effect of process parameters on processing properties. A BP prediction model was constructed with process parameters as input and comprehensive evaluation Z as output. Based on the model, PSO was used to optimize process parameters, and experimental validation was conducted. It turns out that the relationship of MRR with workpiece speed is linear, with working gap and polishing disc speed are sinusoidal, and with yaw speed is quadratic. The relationship between Sa and four process parameters are quadratic. The R2 of the model is 0.9609. The error of the predicted Z is less than 3.45%. The optimal combination predicted is: workpiece speed 700r/min, working gap 3.1mm, yaw speed 115mm/min, and polishing disc speed 60r/min. The predicted Z is 39.96, the actual Z is 41.93, with an error of 4.9%. [ABSTRACT FROM AUTHOR]

Featured Application: Few or no finishing systems are specifically available for 3D printable materials for permanent dental restorations. The generic systems tested in this study were generally able to give clinically acceptable results for roughness. Conversely, the outcome was poor for gloss, except for curing in a nitrogen chamber unit. The results suggest the need to develop finishing/polishing systems dedicated to this specific category of prosthetic materials. The object of the study was to assess the effect of different finishing and polishing systems on the roughness and gloss of a 3D-printed permanent restorative material. One 3D printable Permanent material was selected for the study. Squared-shaped specimens (14 mm2; 5 mm thickness) were obtained by designing and printing. Eighty specimens were produced and randomly assigned (n = 10) to 8 finishing and polishing methods: Sof-Lex™ Spiral Wheels (SW), Sof-Lex™ XT Pop-on Disc (SD), Identoflex Lucent no paste (Ln), Identoflex Lucent + paste (Lp), Resin Nitrogen polymerized (NG), Optiglaze (OG), Opti1Step (OS), and HiLusterPLUS (HL). Surface roughness and gloss were then measured by a roughness meter and a glossmeter, respectively. For roughness, statistically significant differences were found (p < 0.001), with NG(a) > SD(b) = OG(b) = Lp(b); Lp(b) = Ln(bc); Ln(bc) = OS(cd); OS(cd) = SW(de); and SW(de) = HL(e). For gloss, statistically significant differences were also identified (p < 0.001) with NG(a) > SD(b) > Lp(c) = OS(c) = OG(cd); OG(cd) = Ln(d) > HL(e) = SW(e). The nitrogen chamber polymerization showed better results for both roughness and gloss. Multi-step finishing/polishing systems were able to produce smoother surfaces than 1-step and 2-step systems. [ABSTRACT FROM AUTHOR]

Ceramic cutting inserts are a type of cutting tool commonly used in high-speed metal cutting applications. However, the wear of these inserts caused by friction between the workpiece and cutting inserts limits their overall effectiveness. In order to improve the tool life and reduce wear, this study introduces an emerging method called magnetic field-assisted batch polishing (MABP) for simultaneously polishing multiple ceramic cutting inserts. Several polishing experiments were conducted under different conditions, and the wear characteristics were clarified by cutting S136H steel. The results showed that after 15 min of polishing, the surface roughness at the flank face, edge, and nose of the inserts was reduced to below 2.5 nm, 6.25 nm, and 45.8 nm, respectively. Furthermore, the nose radii of the inserts did not change significantly, and there were no significant changes in the weight percentage of elements before and after polishing. Additionally, the tool life of the batch polished inserts was found to be up to 1.75 times longer than that of unpolished inserts. These findings suggest that the MABP method is an effective way to mass polish ceramic cutting inserts, resulting in significantly reduced tool wear. Furthermore, this novel method offers new possibilities for polishing other tools. [ABSTRACT FROM AUTHOR]

As an important indicator of the surface quality of workpieces, surface roughness has a great impact on production costs and the quality performance of the finished components. Effective surface roughness prediction can not only increase productivity but also reduce costs. However, the current methods for surface roughness prediction have some limitations. On the one hand, the prediction accuracy of classical experimental and statistical-based surface roughness prediction methods is low. On the other hand, the results of deep learning-based surface roughness prediction methods are uninterpretable due to their black-box learning mechanism. Therefore, this paper presents an ensemble learning with a differential evolution algorithm, applies it to the prediction of surface roughness of abrasive water jet polishing (AWJP), and conducts an interpretability analysis to identify key factors contributing to the prediction accuracy of surface roughness. First, we proposed automatically constructing features by an Evolution Forest algorithm to train the base regression models. The differential evolution algorithm with a simplified encoding mechanism was then used to search for the best weighted-ensemble to integrate the base regression models for obtaining highly accurate prediction results. Extensive experiments have been conducted on AWJP to validate the effectiveness of our proposed methods. The results show that the prediction accuracy of our proposed method is higher than the existing machine learning algorithms. In addition, this is the first of its time for the contributions of machining parameters (i.e., features) on surface roughness prediction by using interpretable analysis methods. The analysis results can provide a reference basis for subsequent experiments and studies. [ABSTRACT FROM AUTHOR]

As a result of studying the mechanism of optical glass polishing by means of disperse systems from ceria powders, it has been established that glass is eliminated via the removal of sludge nanoparticles from the treated surface during its interaction with polishing powder particles, which occurs in an open microresonator formed by the surfaces of the treated material and polishing powder particles due to Förster resonant energy transfer between the energy levels of polishing powder and treated material particles. It has been shown that, in a bimodal system with a discrete spectrum of natural frequencies, the number of sludge nanoparticles generated in the treated surface–disperse system–lap surface grows with an increase in the bulk wear coefficient, the lifetime of the excited state of treated surface clusters, and the microresonator Q factor. A method of calculating the treated material removal rate and the roughness parameters of polished surfaces has been developed to establish that the deviation of the calculated polishing rate from experimental data is less than 2%, and the errors of calculating the arithmetic mean Ra and mean square Rq deviations of the polished surface profile attain 10%, and the calculated maximum profile height Rmax is 40–50% underestimated as compared to experimental data. [ABSTRACT FROM AUTHOR]

The infrared conformal window is one of the most critical components in aircraft. Conformal windows with high performance bring low aberrations, high aerodynamic performance, reliability in extreme working environments, and added value for aircraft. Through the past decades, remarkable advances have been achieved in manufacturing technologies for conformal windows, where the machining accuracy approaches the nanometer level, and the surface form becomes more complex. These advances are critical to aircraft development, and these manufacturing technologies also have significant reference values for other directions of the ultra-precision machining field. In this review, the infrared materials suitable for manufacturing conformal windows are introduced and compared with insights into their performances. The remarkable advances and concrete work accomplished by researchers are reviewed. The challenges in manufacturing conformal windows that should be faced in the future are discussed.

Millets are widely recognized for their nutritional significance; however, the methods employed for their processing are currently lacking. This article primarily focuses on the advanced technologies and progressions in millet dehulling and polishing. These technologies operate based on the fundamental principles of compression-shearing, abrasion-friction, and centrifugal-impact forces. Processing of millets can be challenging because of the physical characteristics and tight attachment of hull and bran to the endosperm. However, several dehullers have been designed to solve this problem for different kinds of millets. In addition, the nutritional and anti-nutritional characteristics undergo alterations due to both dehulling and polishing processes. These alterations are thoroughly examined and discussed in this article. Specifically, anti-nutrients such as tannins and phytate are predominantly found in the outer pericarp of the grain and experience a reduction after undergoing dehulling and polishing. The nutritional properties are also subjected to a reduction; however, this reduction can be mitigated by subjecting the grains to certain pretreatments before dehulling and polishing. These treatments serve to enhance dehulling efficiency and nutrient digestibility while simultaneously reducing the presence of anti-nutrients. Novel thermal and non-thermal methodologies such as microwave, hydrothermal, high-pressure processing, and ohmic heating can be employed for processing millets, thereby diminishing the loss of nutrients. Additional research can be carried out to investigate their impact on the dehulling and polishing of millets.

Abstract Ceramic cutting inserts are a type of cutting tool commonly used in high-speed metal cutting applications. However, the wear of these inserts caused by friction between the workpiece and cutting inserts limits their overall effectiveness. In order to improve the tool life and reduce wear, this study introduces an emerging method called magnetic field-assisted batch polishing (MABP) for simultaneously polishing multiple ceramic cutting inserts. Several polishing experiments were conducted under different conditions, and the wear characteristics were clarified by cutting S136H steel. The results showed that after 15 min of polishing, the surface roughness at the flank face, edge, and nose of the inserts was reduced to below 2.5 nm, 6.25 nm, and 45.8 nm, respectively. Furthermore, the nose radii of the inserts did not change significantly, and there were no significant changes in the weight percentage of elements before and after polishing. Additionally, the tool life of the batch polished inserts was found to be up to 1.75 times longer than that of unpolished inserts. These findings suggest that the MABP method is an effective way to mass polish ceramic cutting inserts, resulting in significantly reduced tool wear. Furthermore, this novel method offers new possibilities for polishing other tools.

A novel approach to enhancing the efficacy and surface quality of magnetic polishing involves the incorporation of a magnetic liquid circulation system for abrasive particle regeneration in conjunction with a circular Halbach array. The continuous renewal of abrasive particles within the polishing zone is realised through a conveyor belt that transports new abrasive particles into the polishing liquid solution. This formation of a continuously circulating polishing system ensures uninterrupted magnetic finishing processes and maintains stability throughout the polishing operation. This study extensively explores polishing force distribution, magnetic field distribution and abrasive grain behaviour in the polishing area facilitated by the magnetic liquid solution. The application of the proposed polishing processes to polymethyl methacrylate, an optical lens material, aims to comprehend the characteristics and validate the feasibility of the polishing method. Key influencing factors in the magnetic polishing process, including abrasive grain size, magnetic particle, polishing distance and conveyor speed to surface quantity, are examined through experimental analysis. Results of the experimental polishing processes demonstrate that the utilisation of circular Halbach arrays with circulating abrasives produces a nanometric surface finish. Even in the polishing of polymethyl methacrylate with an initial rough surface (Ra = 464.895 nm), the process achieves an ultra-fine level with Ra below 9 nm without disruption in the material polishing processes of optical lenses.

Many industrial components, especially those realized through 3D printing undergo surface finishing processes, predominantly, in the form of mechanical polishing. The polishing processes for custom components remain manual and iterative. Determination of the polishing endpoints, i.e., when to stop the process to achieve a desired surface finish, remains a major obstacle to process automation and in the cost-effective custom/3D printing process chains. With the motivation to automate the polishing process of 3D printed materials to a desired level of surface smoothness, we propose a dynamic model of surface morphology evolution of 3D printed materials during a polishing process. The dynamic model can account for both material removal and redistribution during the polishing process. In addition, the model accounts for increased material flow due to heat generated during the polishing process. We also provide an initial random surface model that matches the initial surface statistics. We propose an optimization problem for model parameter estimation based on empirical data using KL-divergence and surface roughness as two metrics of the objective. We validate the proposed model using data from polishing of a 3D printed sample. The procedures developed makes the model applicable to other 3D printed materials and polishing processes. We obtain a network formation model as a representation of the surface evolution from the heights and radii of asperities. We use the network connectivity (Fiedler number) as a metric for surface smoothness that can be used to determine whether a desired level of smoothness is reached or not. [ABSTRACT FROM AUTHOR]

Objective Materials and Methods Results Conclusions Clinical Significance To evaluate the effect of polishing and bleaching on the recovery of lightness, color, whiteness, and relative translucency parameter (RTP) in CAD/CAM materials and changes in these properties when another staining in coffee was conducted after the treatments.Disks of Lava Ultimate (LU), Vita Enamic (VE), IPS Empress CAD (EMP), IPS e.max CAD (EMAX), and Vita Suprinity (VS) were (1) not treated (control), (2) polished with Proxyt or (3) Ceramisté, (4) bleached with Opalescence PF or (5) Whiteness HP Blue, and (6) air polished with Clinpro Prophy Powder. CIE L*a*b* color coordinates were registered at baseline (R0), after staining with coffee for 30 min daily for 36.5 days and treatment (R1), and after another staining (R2). Differences (R1–R0 and R2–R0) in lightness (ΔL00), color (ΔE00), RTP (ΔRTP00), and whiteness (ΔWID) were evaluated by mixed repeated measures ANOVA and 95% confidence intervals (α = 0.05) and interpreted in function of their respective 50:50% PT and AT thresholds. Topography was evaluated by scanning electron microscopy (SEM).In LU, Opalescence PF and Proxyt decreased ΔL00R1–R0$$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$, ΔE00R1–R0$$ {\Delta E}_{00\left({R}_1\hbox{--} {\mathrm{R}}_0\right)} $$, and ΔWIDR1–R0$$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_1\hbox{--} {R}_0\right)} $$ and showed lower ΔL00R2–R0$$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$, ΔE00R2–R0$$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$, and ΔWIDR2–R0$$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$. In VE, all treatments decreased ΔL00R1–R0$$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$, ΔE00R1–R0$$ {\Delta E}_{00\left({R}_1\hbox{--} {R}_0\right)} $$, and ΔWIDR1–R0$$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_1\hbox{--} {R}_0\right)} $$, whereas ΔL00R2–R0$$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$, ΔE00R2–R0$$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$, and ΔWIDR2–R0$$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ were lower in Opalescence PF than in the control group. In both moments, ΔE00 and ΔWID in EMP (also ΔL00) and EMAX were higher in Opalescence PF than in the control group, from which the other treatments did not differ in R1–R0. In EMP, ΔE00R2–R0$$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ in Whiteness HP Blue (also ΔL00R2–R0$$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$) and Proxyt were also higher in comparison to the control group and in VS, Ceramisté decreased ΔL00R1–R0$$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$, ΔE00R1–R0$$ {\Delta E}_{00\left({R}_1\hbox{--} {R}_0\right)} $$, and ΔRTP00R1–R0$$ \varDelta RT{P}_{00\left({R}_1\hbox{--} {R}_0\right)} $$, whereas Opalescence PF increased ΔRTP00R1–R0$$ {\Delta \mathrm{RTP}}_{00\left({R}_1\hbox{--} {R}_0\right)} $$. ΔE00R2–R0$$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ of Ceramisté and ΔWIDR2–R0$$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ and ΔRTP00R2–R0$$ \varDelta RT{P}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ of Proxyt were lower than those of the control group.The most suitable treatment to recover the lightness, color, whiteness, and RTP without changing these properties after another coffee exposure is material‐dependent.Although the effectiveness of the treatment was material‐dependent, Proxyt was the only treatment that promoted clinically acceptable changes for both LU and VE, while for purely ceramic materials, this condition was observed with Ceramisté and Clinpro Prophy Powder. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate how two different polishing techniques affect the color stability, surface roughness, and changes in surface morphology of aged and coffee-stained bulk-fill resin composites. A total of 112 disc-shaped samples were prepared using Omnichroma Flow Bulk (OB), Charisma Bulk Flow One (CB), Estelite Bulk Fill Flow (EB), and Estelite Sigma Quick (control). Samples were divided into two subgroups (n = 16) and aged using thermocycling. A profilometer was used to measure the surface roughness (Ra) and a spectrophotometer was used for color stability (ΔE00). The EB group had the highest Ra values both before aging (disc: 0.23 ± 0.05, twist: 0.42 ± 0.05) and after aging (discs: 0.28 ± 0.04, twist: 0.46 ± 0.05). The OB group had the highest ΔE00 values before and after aging (discs: 3.06 ± 0.54, twist 3.05 ± 0.41) and the highest after coffee-staining (discs: 3.75 ± 0.70, twist: 3.91 ± 0.57). Re-polishing reduced the ΔE00 values in all materials but did not restore all to clinically acceptable levels. According to the results of this study, it can be concluded that the surface roughness and color stability of resin composites are notably influenced by the polishing technique, aging process, and coffee staining. Specimens that were polished using the multi-stage Super-Snap discs consistently exhibited smoother surfaces across all bulk-fill resin composites compared to those polished with the two-stage Diacomp plus Twist. [ABSTRACT FROM AUTHOR]

Nanofinishing of blind-hole cavities is important to produce high quality products without any surface irregularities. The commonly used methods such as grinding or honing are not efficient because of the uncontrolled forces and direct contact of the solid abrasive tool with the workpiece. Magnetorheological (MR) polishing process using smart fluid has proved its effectiveness in achieving the nano-finished surface. The existing tool design uses two different operations for nano-scale finishing of a blind-hole cavity, resulting into a higher production cost. In this present work, a novel tool that can vary its dimensions during finishing operation was developed for enhancing the surface finishing of blind-hole cavities. Distribution of magnetic fields within the entire tool and blind-hole cavity surface was found appropriate and also revealed that the tool surface has maximum magnetic field for stiffening the MR polishing fluid over its surface. After 90 minutes of finishing, it was concluded that the roughness (Ra) change on the blind-hole cavity were reduced by 75.12% (on inner vertical) and 74.21% (on inner bottom). [ABSTRACT FROM AUTHOR]

The precise surface finish and geometric accuracy of cylindrical rollers play a vital role in determining the longevity of bearing. To evaluate the effects of abrasive size and machining load on the surface roughness of GCr15 steel cylindrical rollers in the lapping and polishing process, existing measured data for the process parameters are tabulated as per the Taguchi's L9 OA (orthogonal array). The Analysis of variance (ANOVA) was conducted to determine the optimal process parameters. Empirical relations for the surface roughness (SR) and roundness (R) of the rollers are developed in regard to the process parameters. The adequacy of empirical relationships is demonstrated by measured data. The SR of CNC-turned cylindrical rollers made of GCr15 steel is appreciably reduced with SiC abrasive particle size in the lapping process and further slightly reduced in polishing process with Al2O3 abrasive particle size. This study demonstrates the possibility of achieving a finer surface finish on cylindrical rollers after a lapping and polishing process. [ABSTRACT FROM AUTHOR]

This research has developed a fabricating process of thin‐strain sensor by utilizing wafer‐level‐packaging (WLP) techniques. The thickness of sensor makes thinner, its performance is able to highly increase. However, the thinner sensor was fragile, and so it was difficult to handle in post processes. Thus, a thin sensor with lid by utilizing WLP techniques, which is tough to break even when handled, is proposed in this research. More than 250‐µm‐deep grooves were fabricated around the lid by deep reactive ion etching. After the lid substrate was bonded on the sensor substrate with a resin, the sensor and lid substrates were respectively polished to 50 and 200 µm thickness. The lids were released along the grooves, and the 50‐µm‐thick strain sensors were able to be fabricated by utilizing WLP techniques. This sensor was used as a diaphragm to measure pressure. The sensors were assembled on a stainless steel housing without breakage. The performance of the developed sensor was almost showed with a conventional pressure sensor. [ABSTRACT FROM AUTHOR]

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The scientific basis is established for selecting the fewest surface roughness characteristics in machining by the following methods: turning, face milling, surface grinding, and polishing. [ABSTRACT FROM AUTHOR]

Polishing abrasives play a crucial role in polishing and significantly influence the polishing rate and quality. Current research on direct observation of abrasives under polishing tools with complicated surface textures is limited. In this work, high speed camera is applied to observe the abrasives under morphable polishing tools with smooth, labyrinth and dimple textures at the tool rotational speed (300, 600 and 900 rpm) and tool offset (0.2, 0.5 and 1 mm). The results shows that the number of abrasives in the contact area is increased with the tool rotational speed and decreased with the tool offset. Among the three tools, dimple tools retain more abrasives than labyrinth and smooth tools. Abrasive trajectories are nearly horizontal, in accordance with the polishing velocity direction. The velocity magnitude is mainly influenced by the horizontal velocity u, as the vertical velocity v is relatively small. The velocity magnitude increases with the tool rotational speed and the tool offset. Among the three tools, the velocity is higher under labyrinth and dimple tools than under smooth tools. The pressure and abrasive velocity were increased by ~ 25% and 70%, while the resultant removal volume was increased by 54.2% with a dimple tool than a labyrinth tool. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate how different polishing techniques and coffee thermal cycling affect the surface roughness and stainability of additively and subtractively manufactured resins used for definitive prostheses. Materials and Methods: Two additively manufactured composite resins (Crowntec, CT and VarseoSmile Crown Plus, VS) and a subtractively manufactured resin nanoceramic (Cerasmart, CS) were used to fabricate 90 rectangular‐shaped specimens (14 × 12 × 1 mm) (n = 30). After baseline surface roughness (Ra) measurements, specimens were divided into three groups based on the polishing technique; conventional polishing with a 2‐stage polishing kit (CP) and surface sealant application (Optiglaze, OG or Vita Akzent LC, VA) (n = 10). After polishing, specimens were subjected to 10,000 cycles of coffee thermal cycling. Ra and color coordinate measurements were performed after polishing and after coffee thermal cycling. Color difference (ΔE00) was calculated. Scanning electron microscope images were taken at each time interval. Kruskal–Wallis or 1‐way analysis of variance (ANOVA) were used to evaluate Ra of materials within each polishing‐time interval pair and different polishing techniques within each material‐time interval pair, while Friedman or repeated measures ANOVA were used to evaluate Ra at different time intervals within each material‐polishing pair. ΔE00 was assessed with 2‐way ANOVA (α = 0.05). Results: Other than VA‐after polishing (p = 0.055), tested materials had significantly different Ra within each polishing‐time interval pair (p ≤ 0.038). When Ra differences among different polishing techniques within each material‐time interval pair were considered, CS had differences after coffee thermal cycling, CT had differences before polishing and after coffee thermal cycling, and VS had differences within each time interval (p ≤ 0.038). When Ra differences among different time intervals within each material‐polishing pair were considered, significant differences were observed among all pairs (p ≤ 0.016), except for CS‐VA (p = 0.695) and VS‐VA (p = 0.300). ΔE00 values were affected by material and polishing technique interaction (p = 0.007). Conclusions: Ra of CS was similar to or lower than the Ra of other materials, regardless of the time interval or polishing technique. CP mostly led to lower Ra than other polishing techniques, whereas VA resulted in a high Ra regardless of the material‐time interval pair. Polishing reduced the Ra, while coffee thermal cycling was found to have a small effect. Among tested material‐polishing pairs, only CS‐VA had moderately unacceptable color change when previously reported threshold values were considered. [ABSTRACT FROM AUTHOR]

The investigation into the mechanism of polymethylmethacrylate (PMMA) polishing using dispersed systems of micro- and nanoparticles of polishing powders revealed that the formation of slurry particles in the processed material is driven by Förster resonance energy transfer between the energy levels of the polishing powder particles and the processed material. This transfer occurs within the open microcavity created by the surfaces of the processed material and the polishing powder particles, in a multimode regime. The material removal rate during PMMA polishing is determined by the combined coefficients of volumetric wear and the total lifetime of the excited states of clusters on the processed surface, along with the resulting quality factor of the resonator at all allowed frequencies of the discrete spectrum. The results of the theoretical calculation of the material removal rate during PMMA polishing are in good agreement with the data from the experimental determination of polishing performance, with a deviation of 1–3%. [ABSTRACT FROM AUTHOR]

To overcome the problems of low slurry utilization and poor surface uniformity in conventional small tool polishing of curved surfaces, a small tool polishing method based on slurry dielectrophoresis (STP‐DEP) is proposed. The dielectrophoretic effect distributes the slurry evenly and increases its dwell time in the processing area, enabling more abrasives to participate in polishing, thereby improving the material removal efficiency and surface uniformity of the workpiece. The observation experiment indicates that dielectrophoresis can efficiently distribute the slurry evenly. Compared with the traditional small tool polishing, the results show that the polishing efficiency of the STP‐DEP is improved by 34% on the premise of achieving the same surface roughness Ra of the workpiece. The Taguchi experiments are carried out on K9 convex lens. Results show that the optimal surface roughness Ra 3.3 nm (initial Ra 2400 nm, processing time 120 min) is obtained when the tool speed is 400 rpm, the pressing amount is 1 mm, the infeed angle is 15°, and the abrasive size is 3 μm. The research proves that the STP‐DEP successfully solves the problem of slurry uneven distribution, and realizes efficient surface polishing with high surface uniformity. [ABSTRACT FROM AUTHOR]

Solutions containing hydrofluoric acid (HF), hydrobromic acid (HBr) and bromine (Br2) were investigated as novel acidic, NOx-free mixtures for wet-chemical etching of silicon wafers. HF–Br2-mixtures exhibit isotropic etching behaviour towards silicon, etch rates up to 4.0 ​μm ​min−1 were observed at room temperature, which are higher than the etch rates of commercially used alkaline solutions. HF–HBr–Br2-mixtures show anisotropic etching behaviour, texturing the surface of monocrystalline silicon wafers with random upright or random inverted pyramidal structures. Etch rates up to 2.4 ​μm ​min−1 were observed, the etch rate increases linearly with the concentration of Br2 in the etching solution. Silicon surfaces were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The light trapping efficiency of wafers etched by HF–HBr–Br2 solutions was compared to commercially available textured wafers by UV/Vis-reflectivity measurements indicating lower reflectivities for the HF–HBr–Br2-treated samples. A reaction scheme for the anisotropic dissolution of silicon in bromine-containing aqueous HF-solutions is proposed, which involves bromine as oxidizing agent.

ABSTRACTFinishing and polishing dental ceramics after chairside adjustments is necessary to regain the original surface topography. Though highly subjective, visual and tactile assessment are the most practical ways to assess surface roughness clinically. Several manufacturers recommend polishing kits for specific ceramic materials that differ in efficacy. Proper polishing protocols require the use of sequential polishing instruments that reduce the size of the adjustment abrasions, improve aesthetics and reduce plaque accumulation. If polishing systems are interchanged, stepwise use of a zirconia polishing system may have a “universal” effect on different ceramic substrates. Adjusting zirconia restorations could result in phase transformation and potentially compromise flexural strength. The extent of this degradation is dependent on the yttria content of the zirconia. This may be reduced by appropriate finishing and polishing.

The paper reports on the developed technique for polishing single-crystal silicon substrates using a mechanical lap. The effective substrate roughness was obtained in the spatial frequency range of 0.025–65 µm–1 at the level of 0.37 and 0.18 nm at a frame size on the surface of 2 × 2 µm2. The result obtained is comparable with the results of chemical-mechanical and dynamic polishing of single-crystal silicon wafers for microelectronics. [ABSTRACT FROM AUTHOR]

This in vitro study evaluated the surface roughness (Sa) of two high-strength silicate ceramics, lithium disilicate IPS e.max CAD, Ivoclar Vivadent (LDS group), and zirconia-reinforced lithium silicate Vita Suprinity, VITA Zahnfabrik (ZLS group). The surface roughness was investigated before and after milling using different polishing systems and timings relative to the final crystallization of the ceramics. Forty-eight samples per group were polished by a single calibrated operator using two polishing systems: Dialite LD (Brasseler) and Lithium Silicate Polishers (Meisinger) for the LDS group and Dialite LD (Brasseler) and Vita Suprinity Polishing Set Technical (VITA Zahnfabrik) for the ZLS group, both pre- and post-crystallization. Surface roughness was measured using a confocal laser microscope (OLS4000 LEXT/Olympus), with scanning electron microscopy (SEM) used to evaluate surface morphological changes. Significant differences in Sa values were found between baseline groups, with ZLS exhibiting lower values. All polishing methods significantly reduced surface roughness compared to baseline (p ≤ 0.05). No significant differences were found in LDS samples when polishing pre- or post-crystallization (p = 0.129), while for ZLS samples, post-crystallization polishing achieved significantly smoother surfaces (p < 0.001). The study concluded that the choice of polishing system and timing did not significantly affect surface roughness for LDS. However, it is recommended that post-crystallization polishing be performed for the optimal smoothness of ZLS. This study aimed to evaluate the post-milling polishing procedures of CAD/CAM high-strength restorations, emphasizing the importance of an optimal surface roughness to prevent issues such as increased risk of abrasion on opposing teeth, enhanced plaque adhesion, and mechanical failures. Investigating these polishing techniques enables clinicians to optimize clinical performance, thereby improving the quality and longevity of high-strength silicate ceramics. [ABSTRACT FROM AUTHOR]

When addressing the technical challenges of achieving precise force tracking during the local polishing process of polishing robots, controlling the contact state between the robot and the workpiece surface is essential. To this end, a contact motion-planning strategy based on dynamic systems is designed to generate trajectory routes during local polishing. The trajectory simulation of the local modulation dynamic system is achieved through the employment of the support vector regression (SVR) algorithm with a Gaussian kernel, facilitating the learning process. The feasibility and stability of planning local paths are validated using the local modulation dynamic system. To maintain a constant contact force between the end-effector polishing robot and the workpiece, an integral adaptive impedance control strategy is utilized, enabling the robot's compliant control. Subsequently, an experimental system for the polishing robot is constructed in order to verify the effectiveness of the motion-planning system. The experimental results demonstrate that the proposed motion-planning approach is applicable in practical polishing processes, ensuring smooth contact and maintaining the desired contact force when scanning nonlinear surfaces, and thus showcasing stability and practicality. [ABSTRACT FROM AUTHOR]

During the polishing process of complex curved PMMA parts, the polishing force is an important factor affecting the surface quality and optical performance. In this paper, a force-controlled polishing device integrated into a machining center to maintain the polishing force is investigated. In order to achieve the real-time active control of the polishing force, the linear voice coil motor and force sensors are used for motion and measurement. A compact structure was designed to couple the linear motion of the voice coil motor with the rotation for polishing. The force-controlled polishing system with a high real-time hardware architecture was developed to perform complex curved polishing path movement with precise force control. Next, the polishing force between the device and the workpiece was analyzed to obtain the mathematical model of the device. Considering the impact during the approaching phase of polishing, a fuzzy PI controller was proposed to reduce the overshoot and response time. To implement the control method, the controller model was established on Simulink and the control system was developed based on TwinCAT 3 software with real-time computing capability. Finally, a polishing experiment involving a complex curved PMMA part was conducted by a force-controlled polishing device integrated into a five-axis machining center. The results show that the device can effectively maintain the polishing force to improve surface quality and optical performance. [ABSTRACT FROM AUTHOR]

Precision bearings are key components of mechanical equipment, and their quality almost restricts the overall development level of key technologies in the equipment manufacturing industry. As the critical element of precision bearings, the surface quality of rollers significantly affects their operational performance, reliability, and fatigue life. The development of surface finishing technology for rollers is a practical solution to improve their surface quality. However, there is a lack of systematic exposition of the research status and development direction of this technology. This study provides a comprehensive review and summary of the existing surface finishing technology for cylindrical rollers. First, the article introduces the impact of surface integrity on bearing performance. Second, it provides a comprehensive classification and summary of the current surface finishing technologies for cylindrical rollers, which include centerless grinding, superfinishing, electrochemical mechanical finishing, magnetic fluid grinding, double-side lapping, double-disc straight groove grinding, shear thickening polishing, and mass finishing. Third, the surface roughness and roundness error ranges achieved by different finishing technologies are quantitatively compared, and their processing characteristics are comprehensive compared. Finally, the article forecasts the future development trend of surface finishing technology for cylindrical rollers. [ABSTRACT FROM AUTHOR]

The frictional properties of the coarse aggregate used in asphalt concrete are a major contributor to the friction of the surface mixes. Selecting an aggregate that is not only polish and crush resistant to withstand the mechanical degradation and grinding under traffic loading, but also has a low friction loss rate and reasonable friction life is vital. A laboratory aggregate test program was carried out to evaluate the polishing/friction and crushing performance of 25 different aggregate sources from different locations. Two widely used friction test methods, i.e., British pendulum testing (BPT) and dynamic friction testing (DFT) in conjunction with the three-wheel polishing testing (TWPD) and the aggregate crushing value test (ACV) were used to quantify the polishing and crushing resistance of aggregates, respectively. Several frictional and crushing test parameters were introduced, analyzed, and finally, a correlation analysis was performed to relate different aggregate friction, polishing, and crushing test parameters. All three tests showed low variability when replicate samples were compared. A strong correlation (R value of 0.92) was found between the friction loss rate and the ACV test parameters and a linear correlation with R2 of greater than 0.80 was observed between the final friction life of the aggregate and the BPT test parameters. The ACV and TWPD/BPT tests can be potentially considered as an alternative test for friction evaluation of the coarse aggregates in case the DFT device is not available, with some loss in the sensitivity in characterizing marginal materials. [ABSTRACT FROM AUTHOR]

In this study, an existing superfinishing method used for polishing glass surfaces was refined using a five-joint closed-link compact robot with fixed abrasive grains. In previous studies, a voice coil motor was used to control the constant-pressure pressing force while maintaining the polishing force for a relatively short period. However, maintaining the polishing force for long periods is imperative for achieving a high-quality polished surface. Thus, in this study, a strain gauge load cell was adopted in addition to a conventional piezoelectric force sensor to maintain the polishing force for a long period. First, the amounts of DC drift of the piezoelectric force sensor and strain gauge type load cell were compared to confirm the necessity of signal processing as well as the compatibility of long-term force measurement and high-frequency vibration measurement by application. Further, a method was proposed in which the change in the pressing force was recorded from the connected sensor; when the pressing force fluctuated, chatter vibrations were determined to occur, and the pressing force was temporarily set to 0 N. This method could obtain a better polished surface than the proportional-integral-differential (PID) control, which simply controls the pressing force at a constant value. Finally, chatter vibrations could be determined by detecting high-frequency sounds using a sound level meter. Notably, a finely polished surface could be obtained. [ABSTRACT FROM AUTHOR]

In micro-abrasive water jet polishing (MAWJP) technology, where abrasive particles serve as polishing tools, particles tend to form large clusters, leading to increased nozzle wear and diminished material polishing quality. Achieving a polishing solution with good dispersion stability is crucial for enhancing polishing accuracy and minimizing nozzle wear. Therefore, this study employed three dispersants with distinct dispersion mechanisms to examine the impact of each dispersant's concentration on the dispersion stability of the polishing solution across various abrasive concentrations. Through experimentation, the optimal dispersant type and concentration ratio of abrasive to dispersant were determined, and the effect of the selected dispersant on jet polishing performance was validated. The results of the dispersion stability experiment indicated that, in comparison to Na(PO3)6 and polyethylene glycol (PEG), the polishing solution containing 1.0–2.0 wt% phosphoric ester compounds exhibited a more stable dispersion effect (zeta potential < −50 mV) and superior dispersibility, characterized by a smaller average particle size. Furthermore, K9 optical glass was subjected to fixed-point and local polishing using phosphoric ester compounds as the dispersant. The fixed-point polishing experiment revealed that, at a dispersant concentration of 1.0 wt% and an abrasive concentration of 20 wt%, a smooth and symmetrical material removal profile could be achieved. In the local polishing experiment, the reduction rate of the root mean square of the surface roughness (RMS) increased from 54.33% to 82.24%, and the reduction rate of peak-to-valley height difference in surface (PV) increased from 38.84% to 68.97%. In conclusion, the incorporation of a dispersant proves effective in enhancing the dispersion stability of the polishing solution and dispersibility of the abrasive particles, thereby improving the surface quality of the materials in MAWJP. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of two finishing techniques, glazing or polishing, in comparison with the as‐cut condition, on the biaxial‐flexural‐strength (BFS) of a zirconia‐reinforced lithium silicate ceramic (ZLS). Cylinders were milled from CAD/CAM blocks and sliced to obtain disc‐shaped specimens (ISO6872:2015). Polished and glazed specimens were processed following the manufacturer's instructions. Thirty‐three specimens were obtained for each condition and microstructural and BFS/fractographic characterizations were performed. BFS and roughness data were analyzed using Weibull statistics and ANOVA one‐way with Tukey post‐hoc test, respectively. While a rougher surface was observed for as‐cut specimens, smoother surfaces were observed for polished and glazed ZLS at microscopical evaluation and confirmed through surface‐roughness evaluation. X‐ray spectra depicted a glass phase for all groups and characteristic metasilicate, lithium disilicate, and lithium phosphate peaks for the as‐cut and polished specimens. Glazed specimens showed higher characteristic strength than polished and as‐cut specimens, which did not differ significantly. While higher Weibull‐modulus was observed for the polished than for the as‐cut specimens, no statistically significant differences were noted between glazed and polished, and between glazed and as‐cut specimens. ZLS presents higher strength when glazed, and polishing increases the structural reliability of the material relative to the as‐cut condition. Both finishing techniques reduced surface roughness similarly. [ABSTRACT FROM AUTHOR]

Remediation of disfiguring scratches and abrasions on aging plastics challenges even the most experienced conservator. This study assesses the effect of three NOVUS polishing products on remediation of poly (methyl methacrylate) (PMMA). Samples were prepared to mimic the depth and type of scratches observed during conservation treatment performed on vacuum-formed reliefs from the 1960s. The study compares samples of new/unaged PMMA to naturally aged PMMA samples. Two different methods were successfully used to assess the polishing efficacy, which is notoriously challenging to document in transparent and reflective media: (1) image segmentation analysis of photographs to yield scratched area fractions, using three approaches (Li-thresholding, random forest, and convolution neural network); and (2) optical profilometry measurements, which provide surface root-mean-square roughness (RRMS) values. Both methods support the qualitative observations that polishing with the abrasive NOVUS products significantly reduced the surface damage; scratch area fractions decreased from 50–60% to 1–5% across the aged PMMA types after treatment, corresponding to an ∼85% decrease in surface roughness. Critically, the two methods are complementary: the image segmentation results demonstrated a greater visible difference between two degrees of polishing treatments on the new material, while profilometry results were able to parse differences in the degree of scratch reduction between the aged and new materials. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of different polishing methods on the surface microstructure and roughness of teeth following initial periodontal treatment. Methods: Teeth were divided into three groups (silica onegloss, polishing disc, and polishing strip) in vitro. Tooth surface microstructure was characterized via scanning electron microscopy. Roughness was measured by profilometry and laser scanning confocal microscopy (LSCM). According to the in vitro results, one group was chosen for further clinical trials. Effects of the chosen polishing method on patient plaque control and satisfaction were assessed via plaque staining and visual analog scale (VAS). Results: Electron microscopy results revealed that the polishing disc group had smoother roots and crowns than did the other two groups. Roughness analysis revealed that the crown roughness with the polishing disc and silica onegloss was lower, and the root roughness with the polishing disc was the lowest (p <.05) The LSCM results showed that the pigment deposition depth with the polishing disc and silicon onegloss in the crowns and roots were significantly lower than those with the other two methods (p =.000). The polishing effect of the polishing disc was best among the three groups. Clinical trials were performed to verify the polishing disc effects. Plaque staining results showed that the decrease in plaque in the polishing disc group was greater than that of the rubber cup group (p =.020), which was similar to the results of LSCM. The VAS results showed that the polishing disc made teeth feel smoother, similar to the results of the roughness detection, and the procedure was more comfortable (p <.05). However, there was no significant difference between the two groups regarding foreign body sensation during pronunciation (p =.178). Conclusion: Combining in vitro and in vivo evaluations, the use of a polishing disc following periodontal treatment yielded superior polishing effects on teeth and was better accepted by patients. [ABSTRACT FROM AUTHOR]

The investigation revealed patterns in the formation and localization of deposits of polishing powder wear nanoparticles on the processed surface during the polishing of polymeric materials using disperse systems of micro- and nanopowders. The total scattering cross section of polishing powder wear nanoparticles on sludge nanoparticles increases nonlinearly with the movement of particles, extremally depends on the product of spectral separation for dielectric constant separation between the processed material, polishing powder, and the disperse system, and exponentially increases with the resonator detuning. When polystyrene is polished using cerium dioxide micropowder, deposition on the processed surface is most likely to occur, with the maximum value of the total scattering cross section of polishing powder wear nanoparticles on sludge nanoparticles being at 49.7 Mb. Experimental data indicate that the localization of deposits with polishing powder wear nanoparticles on the processed surface occurs according to the distribution function of the total scattering cross section of polishing powder wear nanoparticles on sludge nanoparticles across circular zones, which aligns well with experimental results, within 12.5%. The experimentally determined average thickness of the deposit fragments of polishing powder wear nanoparticles, forming complete or partial coverage of the component surface, ranges from 1.1 to 1.5 µm. [ABSTRACT FROM AUTHOR]