Higher Surface Roughness Values Research Articles

Effect of polishing methods on the surface roughness of different temporary restorative materials

Aim: The purpose of this study was to evaluate the effects of different polishing methods on the surface roughness of temporary prosthetic restorations. Methodology: In this study, 200 specimens were obtained from Structur 2, Imident, FSM Duo CAD, and Han Temp Crown. All specimens were sanded with 400-, 800-, and 1000-grit silicon carbide. Next, the specimens were divided into five subgroups (n = 10). The specimens in first group were sanded with 1200-, 1600-, and 2000-grit silicon carbide sandpaper. The second group was polished with an aluminum oxide-containing disc. The third group was polished with a diamond-containing pad. A glaze bond was applied to the specimens in the fourth group. The fifth group was glazed with a coat of nano-filled resin. Then, the surface roughness of all specimens was measured with a profilometer. A two-way ANOVA test was performed using SPSS 20.0. Finally, the microstructures of the surfaces were examined by a scanning electron microscope at 5000× magnification. Results: Statistically significant results were obtained between the temporary materials and polishing methods in terms of surface roughness (p < 0.05). For the polishing method, the highest surface roughness values were observed in the control group (0.50 ± 0.15). The lowest surface roughness values were observed in the Equia Forte GC coat group (0.25 ± 0.10). Among the temporary crown materials, the highest roughness was observed in Imicryl specimens. (0.45 ± 0.17), while the least roughness was the polymethyl-methacrylate (PMMA) specimens (0.17 ± 0.10). Conclusion: Surface polishing and finishing procedures might positively affect the surface roughness of temporary materials. Furthermore, materials made via computer-aided design and computer-aided manufacturing (CAD-CAM) demonstrate structural advantages and may be preferable. How to cite this article: How to cite this article: Kavut İ, Uğur M, Tanrıkut ÖO. Effect of polishing methods on the surface roughness of different temporary restorative materials. Int Dent Res 2022;12(3):149-57. https://doi.org/10.5577/intdentres.2022.vol12.no3.7 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Influence of Fiber Laser (1064 nm) on Shear Bond Strength of Titanium Abutment and Resin Cement.

Introduction: The present study was performed to evaluate the influence of a 1064 nm fiber laser on shear bond strength (SBS) at the interface of titanium and resin cement. Methods: Forty titanium discs of 6 mm × 3 mm (diameter and thickness respectively) were categorized into four groups (n=10): control group without any surface treatment and three groups treated with a fiber laser with 81 ns pulse duration, 30 kHz frequency, 10000 mm/s scanning speed, 0.05 mm spot size, and different average power values (3, 5 and 7 W) depending on the tested group. Titanium disc characterization was performed by the scanning electron microscope (SEM) and surface roughness tester. Phase analysis was achieved using an X-ray diffractometer (XRD). Following these tests, resin cement application to titanium discs was performed. SBS values were determined by the universal testing machine. After debonding, the surface of titanium discs was examined by the stereomicroscope for the determination of failure modes. Data analysis was performed using analysis of variance (ANOVA) and Tukey HSD tests (α=0.05). Results: A higher surface roughness value was observed in the 7 W group followed by the 5 W and 3 W groups, and the lowest surface roughness was in the control group. Additionally, the lowest SBS value was obtained from the control group and the highest SBS value was obtained from the 7 W group followed by the 5 W and 3 W groups. Conclusion: SBS between titanium abutment and resin cement can be significantly enhanced by using a fiber laser as a surface treatment considering tested laser parameters; additionally, a positive association between surface roughness and SBS was noted in the experimental groups.

Weathering’s effect on color and roughness in some heat-treated wood species with modified water-based varnish

Heat treatment in wood materials and the use of water-based varnishes (WBV) in furniture made from heat-treated wood materials come to the fore in terms of supporting environmentally friendly production in the wood sector. In this study, the total color changes (ΔΕ*) and surface roughness (SR) were investigated after heat-treated tree species were exposed to natural and accelerated weathering with and without varnish. In this context, test samples were first divided into two groups. Surface treatment was applied to the samples in the first group by applying modified WBV (A1) and normal WBV (A2), and the second group was left unvarnished. Then, one group of the varnished samples was subjected to natural weathering (NAT) for 90 days and the other group was subjected to accelerated weathering (QUV) for 720 h with VAS samples, and then the ΔΕ* and SR values of the samples were calculated. The results revealed that ΔΕ* was the lowest in the QUV WBV group, and NAT was more effective than QUV in ΔΕ*. The highest SR values among all groups were measured in the VAS group, and among the varnished samples, there was no statistical difference between A1 and A2 in SR values, except for Rq.

The Effect of Horn Beetle Nano Chitosan (<i>Xylotrupes gideon</i>) on the Surface Roughness of Glass-Ionomer Cement

The purpose of this study was to evaluate the effect of adding horn beetle nano chitosan (NCH) to Glass Ionomer Cement (GIC) liquid on surface roughness. The evaluation was done before and after the addition of NCH and from the length of time soaking in artificial saliva. The disc sample with a diameter of 6 mm and a height of 3 mm of total 40 samples were divided into four groups: the GIC control group, GIC modified NCH 0.5%, 1%, and 2%. Each sample was immersed for 24 hours and seven days in artificial saliva. Surface roughness before and after immersion was measured using the Surtronic S-100 Series Surface Roughness Tester. Data analysis was performed using a one-way ANOVA test to determine the effect of adding horn beetle NCH and paired t-test to determine the effect of immersion time on the surface roughness of GIC. Although the highest surface roughness values were found in sample GIC modified NCH 1% (2.51±0.86 for 24 hours) and in sample GIC modified NCH 2% (2.64±0.84 for 7 days), there was no significant differences for both the surface roughness with the addition of NCH (p > 0.05) and the length of immersed time (p > 0.05). As the conclusion, there is no effect of horn beetle nano chitosan to GIC surface roughness. However, the addition of horn beetle NCH presented rougher surfaces after immersion. These experiments can help predict the performance of these materials under clinical conditions.

Wear and 3D Micro-Morphological Studies on CAD/CAM Milled Dental Zirconia for Post-Fabrication Dental Processes

The post-fabrication processes on CAD/CAM milled dental Zirconia result in surface roughening, micro-cracking, a decline in surface texture, and loss of strength. Also, the hydrothermal stresses formed due to water, blood, and synovial fluid infiltration into the crack space initiate crack propagation. The present work makes an effort to study the effect of surface morphology due to the post-processing of Yttrium-stabilized tetragonal Zirconia (Y-TZP) after CAD/CAM milling by studying the height, spatial, functional parameters (volume & Stratified surfaces), and 3-D surface roughness parameters in detail. Five groups based on post-processing combinations currently used in clinical conditions were selected for the study. Group 1(G1-S) involved the milling of pre-sintered blocks followed by sintering. Group 2(G2-S+P) consisted of sintering followed by the polishing process. Group 3(G3-S+P+S.B) consisted of sintering, polishing, and sandblasting with Aluminium Oxide (Al2O3) with a particle size of 110µm. Group4 (G4- S+S.B) involved sintering followed by sandblasting. Group5 (G5-S+S.B+P) consisted of sintering, sandblasting, and polishing. The surfaces were evaluated using a 3-D surface profilometer before and after wear. Before wear, the G4 process group responded with the highest surface roughness value, (Average roughness) Sa=1.378±0.409μm, and it was within the limit, which supported osseointegration. Valleys were predominant in almost all the groups, except G4. Also, the peak and core parameters for G3 &G4 were higher and will be of interest for further bone-implant contact (BIC) studies. The groups with sandblasting fabrication processes (G3, G4) exhibited relatively higher 3-D roughness parameters when compared to the groups with fabrication processes (G1, G2, G5). After wear, there was a considerable decline in the material peak. The research revealed that the methods with sandblasting could be suitable for osseointegration, BIC, and in-vivo performance for crown applications. Also, sandblasting followed by polishing (G5) was found to be optimal. Dentists will be able to determine the right clinical adjustments for their chairside CAD/CAM dentistry using 3-D surface roughness morphological analyses. It will also aid researchers in conducting in-depth studies on the issues related to oral cavity.

Quantitative nano-mechanical mapping AFM-based method for elastic modulus and surface roughness measurements of model polymer infiltrated ceramics

ObjectivesThe aim of this in vitro investigation was to assess and compare surface characteristics and nanomechanics of model polymer infiltrated ceramic network (PICN) materials compared to CAD/CAM resin composite blocks. Material and methodsFour model PICN materials sintered at different temperatures (Exp.125, Exp.130, Exp.135 and Exp.155) were investigated along with three CAD/CAM resin composites; Lava Ultimate (LU), Cerasmart (CS) and Grandio Bloc (GB), and one commercial PICN block - Vita Enamic (VE). Forty samples were prepared with dimensions of 14 × 12 × 2 mm for resin ceramic and VE blocks and 15 × 2 mm discs for model PICN materials. All samples were scanned using atomic force microscopy (AFM) (n = 3) at multiple locations and two different scan sizes (20 ×20 µm and 3 ×3 µm). Surface optical gloss (n = 5) at 60° was also determined for all the groups. Data were analysed using one-way ANOVA, and Tukey’s post hoc test (α = 0.05). ResultsResin composite blocks showed smoother surfaces compared to the PICN materials. The average surface roughness values (Ra) ranged from 7.75 nm to 31.21 nm and the gloss value ranged from 56.43 GU to 91.81 GU. The highest surface roughness value was found for Exp.125 (31.21 nm) while LU showed the lowest roughness value (7.75 nm) (the difference being statistically significant: p = 0.001). Variation was noticed in terms of nanomechanical mapping within and between the groups. Images generated from the elastic modulus map values clearly indicated that all PICN materials had more than one phase and very different components. ConclusionsCAD/CAM resin composite blocks exhibited higher gloss and lower roughness values compared to PICN materials. However, both the commercial and model PICN materials showed more stiffness than resin composite with the presence of at least two different phases. Sintering temperature appears to have a significant effect on material topography and nanomechanical properties. The model PICN sintered at 1550 °C showed a comparable range of elastic modulus values to those of enamel.

Antibiofilm Activity, Glucose Absorption, and Surface Roughness of Two Denture Liners Incorporated with Carbon Nanoparticles

This study researched the effect of the addition of carbon nanoparticles (CNs) on the bacterial adhesion, glucose sorption, weight change, and surface roughness of two types of denture liners (Ufigel and Viscogel). CNs were added to liners in four different percentages (0.25%, 0.5%, 1%, and 10%, respectively) by weight (n=10). The biofilm inhibition percentages, glucose sorption, weight change and surface roughness of the CN added denture liners were determined. When the number of independent groups was >2, data analyses were applied using one-way analysis of variance (ANOVA) or the Kruskal-Wallis test, where appropriate. A p value <0.05 was considered to be statistically significant. The highest antibiofilm activity was obtained against C.albicans in the 10% CN added soft denture liner group (51.13%). In terms of the glucose sorption, the addition of CN was not found to have a statistically significant effect on the denture liner groups (p > 0.05). The highest surface roughness values were obtained in the 10% CN added test group (tissue conditioner; 4.95 ± 1.12 μm). This study showed that the addition of CN into two denture liners showed significant antibiofilm effect against C. albicans and S. aureus.

Analisa parameter pada pemotongan plate menggunakan CNC fiber laser cutting terhadap kekasaran permukaan

With the advancement of advanced equipment, Computer Numerical Control (CNC) laser cutting as a manufacturing tool in plate cutting, where industri player make to get maximum result. Laser cutting Cutting is one of the tools used by the industrial world to maximize cutting results. The purpose of this research To find out the results of the difference using the parameters of air pressure and cutting speed on a Q235B carbon steel plate with a thickness of 3 mm using CNC fiber laser cutting on the surface roughness of the material. The method used in this study is a real experimental research method and data analysis to analyze parameters on plate cutting using laser cutting on surface roughness with this number of experiments 9 and 3 replications for the research process by testing surface roughness using Surface Roughness Sj – 210 Mitutoyo. The results showed that the higher the air pressure and the lower the cutting speed, the lower the surface roughness value and vice versa. The lowest surface roughness value is at air pressure of 16 Bar with a cutting speed of 3300/min which is getting a value of 1.499 μm and the highest surface roughness value is at air pressure of 12 bar with a cutting speed of 3400 mm/min which is getting a value of 2.986 μm. dengan kecepatan pemotongan 3400 mm/min yaitu mendapatkan nilai sebesar 2,986 μm.

Effects of Incorporation of Marine Derived Hydroxyapatite on the Microhardness, Surface Roughness, and Fluoride Release of Two Glass-Ionomer Cements

Background: The aim of this study was to evaluate the effects of incorporation of hydroxyapatite (HA) derived from cuttlefish bone on the microhardness, surface roughness (SR), and fluoride release (FR) of conventional cure, and resin-modified glass-ionomer cement. Methods: There were four groups for each tested material; experimental glass-ionomer were made by addition and of 2, 5, and 10 wt % HA respectively to conventional glass-ionomers Fuji II LC and Fuji IX GP Extra. One group was prepared without the addition of HA particles. For SR and microhardness measurements sectional Teflon molds (5 mm in diameter and 2 mm deep) were used to prepare 10 samples per group (n = 80). The samples were stored in distilled water at 37 °C for 7 days prior to testing. The SR was measured using a contact type profilometer and the microhardness was determined using a Vickers micro-hardness tester at a load of 980 g for 15 s. For FR measurements, there were six samples per group (n = 48), prepared in Teflon molds (8 mm in diameter and 2 mm deep). The FR was measured with an ionoselective electrode in triplicates after 24 h, 7 days, and 45 days. Statistical analysis was performed using one-way ANOVA with Tukey post-hoc test. Results and Conclusion: Microhardness values obtained for Fuji II modified with 10 wt % HA were significantly higher compared to the other two groups tested. Comparison of materials with respect to SR showed significant difference between them (p &lt; 0.0001) with Fuji II and Fuji IX modified with HA having higher SR values. Regarding FR, Fuji IX showed statistically significant higher results than Fuji II, independently of HA modification, and groups modified with 2 and 5 wt % HA showed significantly increased fluoride release in all three time points.

Modelling and Analysis of Surface Evolution on Turning of Hard-to-Cut CLARM 30NiCrMoV14 Steel Alloy

Industrial practitioners are working on predictive solutions for the precise evaluation of input parameters and processed surfaces of engineering materials. To aid the aeronautical industry, this study is an effort to develop the mathematical modelling for comprehensive surface analysis of input parameters and surface finish after dry machining of CLARM HBR, a steel alloy with attractive mechanical properties and wide applications in large caliber gun barrels and high-pressure vessels. Feed rate, rotational speed, and depth of cut were taken as quantitative parameters, whereas machining time was considered as a categorical factor with a classification of three levels. Response surface methodology (RSM) with a central component design has been used for the constitution of the experimental design, mathematical modelling, and analysis of developed models. Eighteen samples were prepared to perform the experimentation for the development of prediction models. The adequacy of the developed models was verified using analysis of variance (ANOVA), and the models were validated using confirmatory trial experiments, which revealed the experimental results agreeing with predictions. The feed rate was the most significant parameter in achieving the desired surface finish. An increase in rotational speed at a low feed rate resulted in very fine surface texture, as though it deteriorated the surface finish at higher feed rates. The superior surface quality obtained was 0.137 μm at parametric settings of 0.19 mm/rev feed, 90 rpm speed, 3 mm depth of cut, and 4 min time. Overall, higher values of surface roughness were frecorded in the third level of process variable time. The developed empirical models are expected to aid manufacturers and machining practitioners in the prediction of the desired surface finish concerning different parameters before the experimentations.

Comparison Of The Effect Of Surface Conditioning Methods On The Bond Strength Of Different Zirconia Reinforced Lithium Silicate And Hybrid Ceramics To Resin Cement

OBJECTIVE. The objective of this study was to evaluate the effect of surface conditioning methods on shear bond strength (SBS) of a resin composite bonded to CAD/CAM materials.&#x0D; &#x0D; METHODS. The zirconia-reinforced lithium silicate (Vita Suprinity VS, and Celtra Duo CD) and hybrid ceramics (Vita Enamic, VE and Nacera Hybrid NH) were used. 80 specimens from each material were fabricated following the manufacturer’s instructions and divided into 8 groups according to surface treatments. These were; Gr 1 (control, no treatments (K)), Gr 2 (hydrofluoric acid H), Gr 3 (H+ Silane S), Gr 4 (abraded with 50-micron alumina particles A), Gr 5 (A+ S), Gr 6 (abraded with 30-micron Cojet sand C), Gr 7 (C+S), Gr 8 (S). The average surface roughness (SR) of the specimens was measured. Surface treated specimens were cemented to the resin cement (Panavia F 2.0) for testing the adhesion using the shear bond strength SBS test and were tested. Mean SR and SBS results were analyzed by 2-way ANOVA with the material type and surface treatments as the independent variables. &#x0D; &#x0D; RESULTS. The highest surface roughness values were observed in the A and AS groups. Both hybrid ceramics VE and NH showed the highest SR values among surface treatments. The highest SBS values were found usually on the H and HS treated surfaces. The highest values were observed on the CD material in the HS group (18,01MPa) and followed by the VE material (16,25 MPa) in the CS group. The failure mode for CD and VS materials was found adhesive and cohesive failures and for VE and NH materials adhesive, and mixed cohesive failure was observed.&#x0D; &#x0D; CONCLUSION. The surface treatment showed a significant effect on the SR and SBS values. Although, the SR values of the materials are high in the A and AS group, the highest SBS values were observed in the H and HS treated surfaces.

Effect of Home Bleaching Agents on Color Stability and Surface Roughness of Hybrid Ceramics: An in vitro study.

To evaluate the effect of two different home bleaching agents on the color stability and surface roughness of hybrid ceramics. Three dental hybrid ceramics (Lava Ultimate, CeraSmart, and Vita Enamic) and two different home bleaching agents (hydrogen peroxide [9.5%; HP] and carbamide peroxide [22%; CP]) were used. Thirty specimens with dimensions of 12 x 14 x 1 mm were prepared for each material. Technical polishing kits were applied to one surface of the specimens for the surface finishing procedure. The color parameters (L*a*b*) of specimens were measured. Three subgroups for each ceramic were determined: control (C), HP, and CP (n = 10 each). After bleaching procedures, the color parameters were remeasured, and color differences (ΔE) were calculated. The surface roughness values of the specimens were detected using a profilometer. Surface analysis was performed with a scanning electron microscope on one specimen from each group. Data were analyzed using two-way analysis of variance and Tukey honest significant difference tests. There was an interaction between material and bleaching agent type (P < .05). The highest ΔE values were observed in the CP groups, and the lowest ΔE values were observed in the C groups. For surface roughness, there was no interaction between material and bleaching agent type (P > .05). Material and bleaching agent factors had a significant effect on surface roughness (P Δ .05). The highest surface roughness values were detected in the HP groups. Home bleaching agents caused clinically acceptable color differences on hybrid ceramic materials. HP increased the surface roughness of hybrid ceramics.

EFFECT OF SALBUTAMOL SULFAT EXPOSURE TO THE SURFACE ROUGHNESS OF BIOACTIVE RESIN

ABSTRACTBioactive composite resin is the newest restorative resin material which has good mechanical and aesthetic properties. In the oral cavity, the restoration is degraded due to exposure to acids, one of which is exposure to asthma drugs. Properties of composite resins that can be affected by degradation include surface roughness. This study aims to analyze salbutamol sulfate exposure to the surface roughness of bioactive resins. The research method used was pure experimental design with post test-only with control design. The study used 39 specimens of bioactive resin (8 mm in diameter and 2 mm in thickness), divided into 3 treatment groups, namely the 400µg salbutamol sulfate exposure group, the 800µg salbutamol sulfate exposure group and the artificial saliva control group with treatment every 24 hours for 7 days, subsequently the specimens are tested with the surface roughness of the composite resin using a surface roughness tester. The highest surface roughness value was found in the 800µg group (8.23 ± 0.98 µm), followed by 400 µg group (5.43 ± 1.16 µm) and the lowest in the artificial saliva group (2.63 ± 0.82 µm). There were significant differences in all treatment groups. The exposure of salbutamol sulfate affects the surface roughness of the bioactive composite resin, a higher number of exposure doses indicates a higher surface roughness value.Keywords: bioactive composite resins, salbutamol sulfate, surface roughness

Estimating surface roughness for different EDM processing parameters on Inconel 718 using GEP and ANN

Nickel-based alloys have good mechanical properties along with excellent corrosion and oxidation resistances. Inconel 718, which is in the nickel-based alloy group, has excellent fatigue strength, corrosion resistance, high temperature resistance, and also features such as high strength, toughness and deformation hardening. The biggest disadvantage of Ni alloys is their poor processability. Especially in the machining method, expensive tools should be used. In addition, high surface roughness values ​​obtained as a result of machining in such materials negatively affect the fatigue resistance. On the other hand, difficult-to-machine materials can be manufactured cheaply and easily by methods known as non-traditional production. The most widely used of these methods is the Electrical Discharge Machining (EDM) due to its precision and machining capabilities. The Inconel 718 material used in this study was etched by EDM method using different process parameters. The effects of finishing process parameters on surface roughness after scouring were determined. In the study, the probable surface roughness value estimation model was created by using the process parameters and the surface roughness values ​​obtained as a result of these parameters using the artificial intelligence methods ANN and GEP. For this study, it was concluded that the ANN method is more suitable than the GEP method.

SRTM DEM based Neotectonics from Non-Linear Analysis: A Paradigm through Fractal Analysis

Neotectonics amend the river base and causes landscape erosion. This study explores the DEM based differentiation of neotectonics in the northern regions of Pakistan. This method involves vertical and non-linear dissection base on digital evaluation method. This study uses Gliding Box Technique (GBM and GBT) and Box Counting method to evaluate Lacunarity (LA), Succolarity (SA) or 3-Fractals, and Fractal Dimensions (FD). 3-fractals are an attribute used for the recognition of spatial patterns, specifically to compute and differentiate natural textures including natural patterns. This study also investigates vertical dissection using DEM SRTM having spatial resolution of 90m. DEM SRTM measures surface area, plane area as well as the surface ratio. The vertical areas are investigated to make dissection maps and to identify the affects of neotectonics on the roughness of surface. Low value of surface roughness indicates flattened drainage basins and inclination of slope. The Raikot Fault shows higher values of surface roughness towards NE- SW. The surface roughness is mapped to recognize relative uplifts, uneven regions, depressions and pits. Analysis through non-linear method identifies the regions affected by neotectonics activity. Tectonics activity causes deformation and instability in drainage networks.

WITHDRAWN: Experimental investigation of AA8011 metal matrix composite using grey relational analysis by WEDM

Abstract The metal alloys and composite materials have a fundamental impact in the field of automobile, marine, aircraft, and allied industries. In the ongoing Metal matrix composite (MMC) is made with the consolidation of both AA8011 and silicon carbide which contains properties such as light in weight, resistance to corrosion, and easy maintenance of the final product. MMC is machined by utilizing wire electric discharge machining (WEDM) which cuts all kinds of shapes precisely. Machining operation is performed by utilizing brass wire on an electrically conducting workpiece and it is related to machining performance measures such as material removal rate (MRR), tool wear ratio (TWR), and surface roughness (SR). Low MRR and high SR values thwart considerable appliances of WEDM. The process of optimization is done by utilizing Grey Relational Analysis (GRA). The grey relational grade was determined by a mathematical approach which is conceivable by using the Taguchi method and arranging the parameters in orthogonal array combination.

Depth of Penetration and Surface Roughness Analysis of Al6061 cut by Abrasive Water Jet

In this study, model equations to predict average surface roughness value of abrasive water jet cut aluminium 6061 alloy are developed. Model equations are developed considering water jet pressure, abrasive flow rate and traverse speed of the jet. Model equations help in knowing average surface roughness value on the cutting and deformation wear regions. 27 abrasive water jet cutting experiments are conducted on trapezoidal shaped aluminium 6061 block. Depth of penetration values are found for all experimental cutting conditions. Average surface roughness values are found by non-contact surface roughness tester. Surface roughness testing is carried out along the length of depth of penetration. Low and high average surface roughness values are noticed on the cutting and deformation wear regions respectively. Smooth surface finish and rough surface finish with striations are observed on the cutting and deformation wear regions respectively.

Effects of the granite-forming minerals on the surface roughness in the milling processes

Milling of granite surface is getting increasingly important in the industry. A major problem is that the effect of granite minerals on surface roughness is currently unknown. The research in this article aims to examine these effects. During the experiment, six surfaces with different cutting speeds were examined on the surface of three different granite samples. The color of the various minerals was determined by light microscopy, and a scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to analyze the composition of the samples, and a confocal microscope was used to measure the surface roughness of each mineral. From the results of the investigations, we deduced different correlations between the minerals forming granite and the surface roughness. Area-based surface roughness was used in this study because it results more accurate data. From the results, we conclude that the roughness of different surface-forming minerals varies greatly. This causes a high average surface roughness value.

Effect of Different Surface Treatments on Retention of Cement-Retained, Implant-Supported Crowns

To evaluate the effect of different treatments applied to titanium implant abutment surfaces on the retention of implant-supported cement-retained crowns using resin cement. A total of 72 titanium implant abutments were divided into six groups (n = 12 each) based on the selected surface treatments: (1) untreated; (2) airborne particle abrasion; (3) hydrogen peroxide etching; (4) atmospheric plasma; (5) chemical mechanical polishing; and (6) titanium dioxide (TiO2) nano coating. After the surface treatments, scanning electron microscopy analyses and surface roughness measurements of the abutment surfaces were performed. Seventy-two metal copings were fabricated and cemented on the abutments with dual-curing resin cement. After a thermal cycling process, crown retention was measured using a universal testing machine. The experimental results were statistically evaluated with one-way analysis of variance, Tukey honest significant difference, and Tamhane's T2 tests. The highest surface roughness values were obtained with the airborne-particle abrasion group (1.44 μm), which also resulted in the highest retention values (828.5 N), followed by the hydrogen peroxide-etching group (490.7 N), the atmospheric plasma group (466.5 N), the chemical mechanical polishing group (410.8 N), and the control group (382.6 N). It was determined that airborne particle abrasion, hydrogen peroxide etching, and atmospheric plasma treatments significantly increased the crown retention and that all alternative treatments, except for TiO2 nano coating, worked better than the untreated control.

Investigation into the surface quality and stress corrosion cracking resistance of AISI 316L stainless steel via precision end-milling operation

This study presents a two-fold investigation on precision end-milling of stainless steel (AISI 316L). First, the impact of end-milling variables (cutting speed and feed rate) on the surface quality (surface roughness, microhardness, and surface morphology) was analyzed. The best surface quality with surface roughness (Ra) 0.65 ± 0.02 μm was observed for cutting speed of 140 m/min and 0.025 mm/tooth of feed rate. Microhardness was increased with increment in cutting speed. Second, the impact of surface roughness (Ra) on the stress corrosion cracking under two different mediums, i.e., body solutions (Hank’s solution) and 1 M hydrochloric acid solution, was studied. The investigations showed that the samples with higher surface roughness values were more prone to stress corrosion cracking.