Mean Value Of Surface Roughness Research Articles

In Vitro Evaluation of Remineralization Potential: Whey Extract, Fluoride Varnish, and Fluoride Mouthwash on Bleached Enamel

Background: Extrinsic discoloration is treated with bleaching which increases enamel porosity and roughness. Remineralizing materials is applied to avoid the bleaching side effects. The current study aimed to evaluate time dependent safety of bleaching materials on enamel surfaces roughness, and to assess the remineralizing potential of whey extract as a natural product and to compare it with the commercially available fluoride varnish and fluoride mouthwash after maximum bleaching time (30 min.). Methods: Extracted human incisor teeth without cracks or any enamel defects were used in this study. Teeth were cleaned and decoronated at the level of the cementoenamel junction. A nail varnish was used to cover the entire surface of the crowns of each tooth, leaving a window measuring 4 mm × 4mm. Bleaching material was applied to the enamel of all teeth specimens. The Application of bleaching material was repeated 2 more times, each time for 10 minutes, which amounted in total to 30 min. The specimens in group 1 were soaked in artificial saliva, the specimens in group 2 were soaked in whey extract, the specimens in group 3 were treated with fluoride varnish and group 4 specimens were soaked in fluoride mouthwash. Results: The mean value of the surface roughness of all the teeth specimens was increased significantly after bleaching for 10 minutes, 20 minutes and 30 minutes (p=0.000) when compared with baseline mean value. As well, there was significant direct correlation between application time of bleaching material and mean value of surface roughness (r= 0.94). There were no significant differences (p>0.05) between the specimens of the 4 groups when the mean value of surface roughness compared at baseline and after bleaching. But, after treatment, there was significant difference (p≤0.05) between the 4 groups, with the best result obtained from whey extract and fluoride varnish. Conclusions: The enamel surface roughness is significantly and directly correlated with prolonged application time of bleaching material. Remineralizing materials; whey extract, fluoride varnish and fluoride mouth wash had significantly decreased enamel surface roughness caused by bleaching. Whey extract has statistically the same effect as fluoride varnish on decreasing the surface roughness of bleached enamel surface.

Comparative Evaluation to Surface Roughness of Modified Heat Cured Acrylic Resin by Zinc Oxide Nanoparticles and CAD/CAM Denture Base Materials - In Vitro Study

One of the most promising CAD/CAM approaches is milling denture base materials from highly condensed pre-polymerized resin discs. In an effort to overcome the disadvantages of acrylic resin denture base materials, nano-filler materials have been added as well as denture base chemistry adjusted to strengthen the denture base.This eliminates disadvantages associated with polymerization shrinkage compared to conventional heat-cured acrylic resin. Aim of this study: evaluate the surface roughness of PMMA acrylic resin after strengthening the denture- base by addition of zinc oxide nano-filler material to acrylic resin PMMA with concentration (1%) and compare with milled CAD/CAM and non-modified heat-cured PMMA denture base materials. Materials and methods: thirty specimens of acrylic resin PMMA were prepared and divided into three groups 10 specimens for each groups as follows; Control Group (Group1) without ZnO nanoparticles ; Group (2) with (1%) by weight of ZnO nanoparticles ; Group (3) milled CAD/CAM.Each specimen is of dimension ( 10 x 10 x 3 ) in mm and was fabricated using conventional processing method and milling the CAD/CAM blocks .Results: showed the lowest mean value was recorded by milled CAD/CAM (0.230 Ra) Then the non-significant reduction with mean value (0.312 Ra) by PMMA+ ZnO 1% and highest mean value of surface roughness was recorded by pure PMMA without additive (0.327 Ra).Conclusions: There were significant differences between control group PMMA and milled (CAD/CAM) with slight reduction of surface roughness of PMMA with (1%) Zno nanoparticles.

An assessment of the impact of L.Salvadora persica and G.Tea on the surface roughness and hardness of heat-cured acrylic-based denture soft liners.

Background: Soft denture liners are a type of dental prosthesis that functions as a cushioning material, alleviating the stress induced by the act of chewing. They offer relief to persons who encounter discomfort when wearing complete or partial dentures, particularly when these dentures are situated on rigid surfaces that support the denture. The objective of this study: is to assess the effects of including L.Salvadora persica. and green tea (G.Tea) extract powders on the surface roughness and hardness characteristics of acrylic-based soft liners. Materials & Procedures: 30 specimens were constructed using wax molds and acrylic-based heat-cured denture soft lining material. The standard curing procedure was used. The samples were separated into three equal groups: group A, the control group, with no additives in the soft-liner material; group B, with 5.12% weight percept L.salvadora persica extract powder; and group C, with 5.12% weight present green tea (G.Tea) extract powder. The samples were then prepared for surface hardness and roughness testing. Results: The results revealed that there was a non-significant rise in the mean values of surface roughness for both group B and group C, group B having the highest mean values followed by group C. When compared to the control group, the results showed a considerable rise in the mean values of surface hardness in group (B), which had the highest mean value for surface hardness, followed by group (C). Conclusion: The results of this study indicate that the incorporation of L.salvadora persica at a concentration of 1.024g and green tea (G.Tea) extract powders at a concentration of 1.024g shown a positive impact on the surface hardness of denture soft lining materials

Evaluation of the Effect of Different Glazing Brands on Surface Roughness of Monolithic Zirconia

The effect of glazing on the mechanical properties of monolithic high translucent zirconia is widely used to fabricate highly aesthetic and strong dental restorations using CAD-CAM technology. The purpose of this study was to evaluate the surface roughness of different glazing brands' materials on monolithic Zirconia. 40 specimens from Zirconia block (VITA YZ®XT Color, Diameter 98.4x14mm height) were prepared by computer-aided design/computer-aided manufacturing machined (Imes-Icore, 5 axis, COR TEC 250i dry, Germany). The samples dimension for the surface roughness test (diameter 10 mm and thickness 2 mm) by using a surface roughness testing machine profilometer (TR200, Germany), divided into 3 groups depending on types of glazing brands materials (VITA, VITA AKZENT® Plus, glaze LT, Germany), the second group with (Ivoclar Vivadent, IPS e.max Ceram glaze and stain liquid, Liechtenstein), and the third group with (GC Initial spectrum glaze liquid, Austria). The data were analyzed statistically using the package for social science, (ANOVA) test with the Bonferroni test to accept or reject the statistical hypothesis. For the roughness readings, the GC group had the greatest mean value of surface roughness in zirconia (0.721±0.014), followed Ivoclar group (0.663 ± 0.030), and then the VITA group (0.641±0.021). There was a statistically significant difference between (VITA&GC) and (Ivoclar & GC) with a p-value < 0.05, except between VITA with Ivoclar, there was no statistically significant association with a p-value > 0.05 for both. Zirconia glazed with GC paste (powder, fluid) has higher surface roughness than samples glazed with Ivoclar paste (powder, fluid) followed by the VITA group which has lower surface roughness. The results concluded that the monolithic zirconia glazed with GC glaze material displays a higher surface roughness than Ivoclar and VITA glaze.

Surface properties and Streptococcus mutans biofilm adhesion of ion-releasing resin-based composite materials

ObjectiveTo evaluate the adhesion of Streptococcus mutans (S. mutans) and related surface properties of ion-releasing resin-based composite (RBC) restorative materials. MethodsTwo ion-releasing RBCs, Activa (ACT) and Cention-N (CN), were compared to a conventional RBC (Z350) and a resin-modified glass ionomer cement (Fuji-II-LC). Ten disk-shaped specimens were fabricated for each material (n = 40). After standardized surface polishing procedure, the surface properties of the specimens were evaluated using surface roughness measurements by a profilometer and hydrophobicity using water contact angle measurements. To assess bacterial adhesion, the number of S. mutans bacteria was calculated from colony-forming units (CFU). Confocal laser scanning microscope analysis was done for qualitative & quantitative assessment. The data were analyzed using One-way ANOVA followed by Tukey's post-hoc test to compare the mean values of surface roughness, water contact angle and CFU values. To compare the mean dead cell percentage Kruskal-Wallis rank test and Conover test were used. A p-value of ≤ 0.05 was used to report the statistical significance. ResultsZ350 and ACT had the smoothest surfaces, followed by CN, and the roughest surface was seen in FUJI-II-LC. The lowest water contact angles were seen in CN, and Z350, and the highest were in ACT. S. mutans counts were the highest in ACT and the lowest in Z350 and CN. CN and Fuji-II-LC registered the highest percentage of dead bacterial cells, while the lowest were in ACT. SignificanceSurface properties did not significantly influence bacterial adhesion. More S. mutans bacteria accumulated on ACT than on the nanofilled composite and on CN. CN had antibacterial effects against Streptococcus mutans biofilms.

A Comparative Evaluation of Surface Roughness of Ceramics after Immersion in Different Oral Rinses: An In-vitro Study

Introduction: The novel Coronavirus Disease-2019 (COVID-19) spreads through respiratory droplets, and various strategies have been developed to reduce its spread. One of these strategies is the use of oral rinses, such as chlorhexidine, povidone iodine, and hydrogen peroxide (H2 O2 ), to reduce the viral load. However, while these rinses have advantages in preventing the spread of the virus, they may also have adverse effects on restorative materials in the oral cavity, particularly dental ceramics. The usage of mouthwashes during the pandemic may affect the surface roughness of dental ceramics, leading to plaque accumulation. Aim: The aim of this study was to evaluate the surface roughness of ceramics after immersion in different oral rinses for seven, 15, and 30 days. Materials and Methods: An in vitro study was conducted in the Department of Prosthodontics at Bharati Vidyapeeth Dental College and Hospital, Sangli, Maharashtra, India. The study was conducted over a period of four months, from October 2021 to January 2022. A total of 51 specimens of dental ceramics were fabricated using a mold with dimensions of 10 mm diameter x 2 mm height. These specimens were randomly divided into three groups based on the immersion solution: distilled water, hydrogen peroxide, and povidone iodine. Each immersion cycle lasted for one minute, and the immersion was performed for 30 days. Surface analysis was carried out using a Surftester at intervals of seven, 15, and 30 days. The data were statistically analysed using the Statistical Package for Social Sciences (SPSS) version 26.0. Intergroup comparison (>2 groups) was performed using the Kruskall-Wallis test, and Analysis of Variance (ANOVA) followed by pairwise comparison using the Mann-Whitney U test. A p-value of <0.05 was considered statistically significant. Results: The mean values of surface roughness for povidone iodine were 0.641, 1.569, 2.5047, and 3.4447 at 0, seven, 15, and 30 days, respectively. The mean values of surface roughness for hydrogen peroxide were 0.681, 2.360, 4.0324, and 5.7035 at 0, seven, 15, and 30 days, respectively. The mean values of surface roughness for distilled water were 0.747, 0.994, 1.3312, and 1.6088 at 0, seven, 15, and 30 days, respectively. Conclusion: The surface roughness of ceramics was significantly higher with the use of hydrogen peroxide as a mouthwash, with mean values of 0.681, 2.360, 4.0324, and 5.7035 at 0, seven, 15, and 30 days, respectively, compared to povidone iodine and distilled water. Povidone iodine can be used as a prophylactic oral rinse compared to hydrogen peroxide.

Evaluation of EDM inclusion into the conventional polishing of printed Co-Cr alloy by selective laser melting

Objective: The selective laser melting (SLM) technique used in manufacturing results in a rougher surface that requires more satisfying processing than conventional hand-finishing operations. The electro discharge machine (EDM) has various possibilities in the adjustment of surfaces. The present study assesses whether the participation of the EDM technique with the conventional finishing and polishing methods enables surface improvement for the Cobalt- Chromium alloy fabricated by SLM. Material and Methods: Twenty discs of cobalt chromium alloy were fabricated by SLM, divided equally into two groups: (TF) control group for finishing and polishing in the conventional method in accordance with the manufacturer’s recommendations; and (EF) group for conducting polishing incorporating the EDM method. Results: The EF group recorded the lowest mean value of surface roughness and the highest mean value of micro hardness compared to the TF group. Furthermore, statistically significant differences (P < 0.05) were found for surface roughness as well as micro hardness. Conclusion: Reliance of the electric discharge machine proactively within finishing and polishing procedures promotes competence in the conventional polishing method and improves the surface properties of cobalt chromium alloy printed by SLM technology. KEYWORDS Dental finishing; Cobalt-chromium alloy; Selective laser melting; Electric discharge machine; Additive manufacturing.

Influence of Toothbrush Abrasion and Surface Treatments on Roughness and Gloss of Polymer-Infiltrated Ceramics.

The aim of this study was to compare the surface roughness and gloss of polymer-infiltrated ceramics after simulated in vitro toothbrushing in different storage mediums. Four polymer- infiltrated ceramics were evaluated, Lava ultimate (LU), Vita enamic (EN), Shofu (SH), and Crystal ultra (CU). The control group was a feldspathic ceramic, Vita Mark II (VM). One hundred and twenty specimens (12 × 14 × 2.5 mm) were prepared using a precision saw. For each material (n = 24), the specimens were allocated into two groups, polished and stained. The specimens of each group were stored (for 7 days) in either citric acid (0.2N) or distilled water. Data for surface gloss (ΔE*SCE-SCI) and roughness (Ra) were evaluated before (baseline) and after simulated toothbrushing. For toothbrushing simulation, a toothpaste slurry containing a toothpaste of 100 relative dentin abrasion (RDA) and 0.3 ml distilled water was used for 3650 cycles (7300 strokes) for each specimen. Data were analyzed using t-test and ANOVA. A p-value of ≤ to 0.05 was considered significant. The highest mean value of surface gloss was identified in CU (stained—water) (4.3 (0.47)) (ΔE*) and EN (stained—acid) (4.3 (1.00)) (ΔE*) specimens, whereas the lowest mean value was shown by SH (stained—acid) (2.04 (0.42)) (ΔE*) samples. The highest mean value of surface roughness was observed in SH (0.40 (0.99)) Ra (stained—acid) whereas the lowest in VM (0.13 (0.039)) Ra (polished— water). A significant difference (p < 0.05) was observed in surface roughness and gloss between the materials with simulated toothbrushing, except in VM and LU, respectively. Therefore, it can be concluded that simulated toothbrushing impacts on surface roughness and gloss, irrespective of the storage medium.

The Effect of Addition of Nano hydroxyapatite Powder of Anadara granosa Shells on Surface Roughness of Heat-cured Acrylic Resin

Background: Heat-cured acrylic resin is one of the most widely used denture base materials. However, the residual monomer can reduce its mechanical properties, which affect physical properties such as surface roughness, resulting in high porosity—the results in the growth of fungal colonies. One way to improve these properties is to add a reinforcement material such as nano-hydroxyapatite (HAp) from the Anadara granosa shell. Nano-hydroxyapatite has a large surface area to act as a filler because of its strong bonding capacity and a smoother surface, and a higher density to improve mechanical properties. Purpose: This study aims to determine HAp powder's effect from the Anadara granosa shells on the surface roughness of heat-cured acrylic resin. Methods: This type of research used an experimental laboratory, research design posttest-only control group design. Twenty-four samples were used and divided into three groups: the acrylic resin group with 1%, 3% blood cockles shell HAp, and acrylic resin without HAp with simple random sampling. Results: The results showed that the lowest mean value of surface roughness was in a group with the addition of 3% HAp, at 1.696 ± 0.25058 µm. One-Way ANOVA test on roughness showed a significant difference between groups with p = 0.000 (p &lt;0.05). Conclusion: This study concludes that there is an effect of HAp on the roughness of heat-cured acrylic resin.

Advanced design and manufacturing of custom orthotics insoles based on hybrid Taguchi-response surface method

Herein, a machining strategy to fabricate custom orthotic insoles with high surface finish and wide fit tolerance is presented. CNC milling was used to machine ethylene-vinyl acetate (EVA) foam for insoles with various surface hardness, and the Taguchi-response surface method (TM-RSM) was adopted to optimize the parameters of the CNC milling process (cutting speed, feed rate, tool path strategy, and step over). EVA foam with varying surface hardness and the tolerance of the wide fit insoles corresponding to the surface roughness were analyzed. Subsequently, a mathematical model was established to determine the optimal CNC milling parameters for a standard milling cutter under dry coolants. The results of the six parameters corresponding to the mean values of surface roughness were initially examined using the signal-to-noise ratio of the Taguchi method (TM). The surface roughness obtained with the TM-RSM was up to 4.13% higher than that obtained with the TM. The EVA foam insole with a surface hardness of 50–60 HRC and a wide fit tolerance of 0.75 mm provided the ideal level of comfort and support for patients with diabetes. The results of this study demonstrated that CNC milling provided a better surface finish of orthotic shoe insoles than other methods, which can serve as guidance in the development of machining strategies for insoles made from EVA foam.

Sustainable production of high-uniformity workpiece surface quality in wire electrical discharge machining by fabricating surface microstructure on wire electrode

When the traditional wire electrode is used in wire electrical discharge machining (WEDM), the workpiece surface quality along thickness direction is always nonuniform which has a significant impact to the usability and reliability of workpiece. To address this issue, this paper aims to propose a new method of fabricating surface microstructure on wire electrode (SMWE) for sustainable production of high-uniformity workpiece surface quality. Firstly, an experimental research of workpiece surface quality uniformity is implemented when zinc coated wire electrode (ZCWE) is used. It can be found that the surface roughness (Ra) and surface quality on the middle area are the worst followed by the top area and bottom area. The uniformity of Ra can be up to 0.44. Additionally, the production process of SMWE is described which includes casting, coating, annealing and plastic processing. The forming mechanism of surface microstructure on wire electrode is based on the thermal expansion coefficient of coating layer is lower than that of wire core. And then, compared with ZCWE, the improvements of SMWE on the discharge characteristic and workpiece surface quality uniformity are analyzed. It can be obtained that SWEM can increase the probability of point discharge and the ratio of normal discharge status. Besides, SMWE can reduce the mean value of surface roughness by 17.3%–22.2% and increase the uniformity of surface roughness by 9.5%–52.1%. Namely, the proposed SMWE for sustainable production of high-uniformity workpiece surface quality is feasible. Eventually, the effects of process parameters on the uniformity of surface roughness are also analyzed. It can be found that small discharge peak current, short pulse on time, long pulse off time, high gap reference voltage and appropriate wire speed are recommended for high-uniformity surface quality.

Impact of Hydrofluoric Acid Etching Duration on Translucency, Flexural Strength and Surface Topography of Lithium Silicate Based Glass Ceramic

Purpose: The purpose of the present study is to assess the effect of different hydrofluoric acid etching durations on the translucency, flexural strength and surface topography of a lithium silicate-based glass ceramic (LS). Materials and Methods: Forty LS (Obsidian) samples will were constructed and divided into four groups (n=10 each) according the duration of hydrofluoric acid (HF) application including group (I); (control) as received samples without surface treatment, group (II); ceramic surfaces etched with HF for 10 seconds; following the manufacturer’s recommendations, group (III); ceramic surfaces etched with HF for 30 seconds and group (IV); ceramic surfaces etched with HF for 60 seconds. All treated samples were evaluated for translucency (TP) using spectrophotometer, flexural strength using universal testing machine and surface topographic analysis using SEM and profilometer. Obtained values were statistically analyzed. Results: The highest mean value of translucency and biaxial flexural strength were recorded at the control group. Values then gradually decreased in the subsequent etching times to reach its lowest level after 60 seconds. While the lowest mean value of surface roughness (Ra) was recorded at control group. The mean Ra value gradually increased with the subsequent increase in etching times to reach its highest level after 60 seconds. Conclusions: Increasing HF acid etching duration negatively affects the translucency of lithium silicate based glass ceramic; while it has no effect on its biaxial flexural strength or its surface roughness (Ra).Key WordsBiaxial flexural strength (FS), LS (Obsidian), surface roughness, translucency.

Thin WBx and WyTi1−yBx films deposited by combined magnetron sputtering and pulsed laser deposition technique

The coatings of tungsten borides (WBx) and tungsten borides doped with titanium (WyTi1−yBx) were deposited by using combined magnetron sputtering - pulsed laser deposition technique. In the case of WBx coatings, pure tungsten target was evaporated by a laser pulse at 1064 nm wavelength and pure boron target was sputtered by a magnetron. In the case of WyTi1−yBx coatings, the W2B5 target was sputtered by the magnetron and titanium target was evaporated by the laser pulse at 1064 nm wavelength. The content of titanium dopant changed from 1.1 to 5.5 at.%. The microstructure, chemical and phase composition of deposited coatings were investigated by means of Scanning Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, X-Ray Photoelectron Spectroscopy and X-Ray Diffractometry, respectively. The Vickers hardness and Young's modulus were determined by using the nanoindentation test. Nanocrystalline WB coatings with dominant WB2 phase were obtained at a substrate temperature of 520 °C. The coatings were superhard with a hardness of 47–50 GPa and the mean value of surface roughness was <6 nm. The WBx coatings doped with 5.5 at.% Ti had hardness similar to the coatings sputtered by magnetron from W2B5 target.

Turning titanium metal matrix composites (Ti-MMCs) with carbide and CBN inserts

Despite excellent mechanical and physical features of titanium metal matrix composite (Ti-MMC), hard and abrasive ceramic particles within the matrix structure, as well as high price, may lead to severe difficulties on machining and machinability of Ti-MMCs. Review of literature denotes that only limited studies are available on machining Ti-MMCs with commercial cutting tools under various cutting conditions and cutting tools/inserts. Furthermore, limited studies are available on machinability attributes of Ti-MMC under various cutting conditions used. Therefore, to remedy the lack of knowledge observed, this work intends to report turning Ti-MMCs with carbide, and cubic boron nitride (CBN) inserts under various cutting conditions. The mean values of surface roughness (Ra) and directional cutting forces, as well as flank wear (VB) were studied as the machinability attributes. The microstructural evaluations were conducted to discover the wear modes. Furthermore, the statistical tools were used to present the factors governing machining attributes studied. Adhesion, abrasion, and oxidation were observed as the principle wear modes on the flank sides of the tested inserts. According to experimental results and statistical analysis, the Ra and VB could be controlled by cutting parameters only when CBN inserts were used. Despite the inset used, factors governing both responses were not identical. Although average cutting forces were directly affected by cutting parameters used, however, the relatively low correlation of determination (R2) of directional cutting forces can be attributed to effects of cutting speed, elevated temperature in the cutting zone as well as rapid tool wear which are all correlated to others.

Evaluation of the Functional Impression Technique with Various Impression Materials on the Surface Topography of Dental Stone Casts and Their Effect on Retention

Background: The accuracy of the final prosthesis is affected by the final impression technique and master cast production. The aim of the present study was to evaluate the effect of the functional impression technique with various impression materials on the surface characteristic of dental stone casts and their clinical effect on the retention of complete dentures. Method: Specimens of three impression materials/stone casts were fabricated. The specimens of the impression materials/stone casts were divided into three equal groups (I, II, and III). The impression materials used were as follows: tissue conditioner group (I), zinc oxide (ZEO) (group II) and poly (vinyl siloxane) (PVS) (group III). Cylindrical split aluminium moulds were designed to receive the impression materials and the stone mixture. The surface roughness of the stone cast specimens of the three groups (I, II, and III) was measured with a surface profilometer and analyzed by a scanning electron microscope. A clinical study included five severely resorbed mandibular edentulous alveolar ridges and edentulous maxillary arches. Each subject received three heat-cured acrylic resin dentures, fabricated using the functional impression technique. The three dentures were identical except for the different impression materials used from Groups I, II and III. The retentive force of each denture for each subject was measured. Result: The results of this study revealed that the mean value of surface roughness of the stone cast surface of group I was higher than group II and group III. A statistically significant difference was observed in surface roughness and the retentive dislodging force between the three studied groups. Although using a tissue conditioner as a functional impression material led to a high level of surface roughness and good retention, it could not produce the same smooth surface quality of PVS or ZEO. These data were supported by SEM analysis. The complete dentures for these patients require important oral and denture hygiene care. Conclusion: Complete dentures made using functional impression technique with PVC as a final impression material are more comfortable, retentive and stable.

KEKASARAN PERMUKAAN RESIN KOMPOSIT NANOFILLER SETELAH PERENDAMAN ALAM AIR SUNGAI DAN AIR PDAM

ABSTRACT Background :One of composite resin kinds is often used for tooth restoration, it is nanofilled composite resin. Nanofilled composite resin is a restoration material containing nano size filler particle, so that it can repair the physical characteristic of composite such as reducing the surface roughness. People in Barito Kuala especially in Desa Anjir Pasar, besides using tap water, they also still use water from river for daily use. The water of river in Desa Anjir Pasar has acid characteristic with Ph range 3-5. An acidic environment causes surface roughness of nanofilled composite resin which allow the secunder caries.Purpose : The aim of this research was to know the difference in surface roughness of nanofilled composite resin after being immersed in river water, tap water, and sterile aquades. Method :This research was a true experimental research with post test only and control group design, used nanofilled composite resin disc samples with diameter of 10 mm and 2 mm thick divided into 3 groups of treatment. Each group was immersed in sterile aquades (as control group), tap water, and river water with acid Ph for 8 days (equals to 3 years of exposure), then the surface roughness was measured using surface roughness measurement. Result : Data was tested using parametric analysis one way anova 95% ( = 0,05) and it obtained p = 0,000 (p = < 0,05). Based on the result it can be concluded that there was significant difference in surface roughness on nanofilled composite resin which had been immersed in each water sample for 8 days. Conclusion : Nanofilled resin composite immersed in river water had higher mean value of surface roughness compared to immersion in sterile aquades and tap water. Keywords: Resin Nanofilled Composite, River Water, Tap Water, Surface Roughness

Comparison of Oxygen Plasma Treatment and Sandblasting of Titanium Implant-Abutment Surface on Bond Strength and Surface Topography.

This in vitro study was designed to compare the effects of oxygen plasma and sandblasting treatment of the surface of titanium implant abutments on retention of implant-supported fixed prostheses using eugenol-free provisional cement and surface topography. Cement failure mode and elemental composition were surveyed. Thirty implant abutments were used. They were divided into three groups (n = 10 implants) according to the surface treatment made (no treatment, sandblasting with 50 μm Al2O3, and oxygen plasma). Thirty metal copings were fabricated with an occlusal metal O-ring and cemented using eugenol-free cement. The tensile bond strength was recorded using a universal testing machine, cement failure was recorded, surface topography was determined using the optical method, and elemental composition was determined using energy-dispersive x-ray spectroscopy. Data from all the groups were compared with a one-way analysis of variance (ANOVA; P < .05) and Tukey test. The mean values of tensile bond strength of metal copings bonded to three implant-abutment surface groups with either control, sandblasting, or oxygen plasma were 138.8 ± 10.2, 261.3 ± 20.6, and 264.7 ± 12.8 N, respectively. The cements failed adhesively in the control and oxygen plasma groups and cohesively for sandblasting. The mean values of surface roughness were 1.1 ± 0.2, 2.3 ± 0.5, and 1.0 ± 0.1, respectively. The oxygen plasma-treated group evidenced a decreased level of C and increased levels of O2. The retention of cast crown copings to titanium implant abutments using eugenol-free provisional cement in the sandblasting and oxygen plasma groups was more improved than in the control group.

Residents' journal review

Residents' journal review

Effects of some chemical surface modifications on resin zirconia adhesion

ObjectivesTo evaluate the effects of various chemical surface modifications on adhesion between zirconia and resin adhesive. Material and methodsPre-sintered zirconia discs were sectioned from commercial cylindrical blocks and polished with abrasive papers under running tap water. All the discs were randomly divided into five study groups according to the methods of surface treatment, including: the control group (fully sintered, without any modification), group S (fully sintered and sandblasted with silica coated alumina particles), group HN (fully sintered and etched with a blend of mineral acid solution at 100°C for 25min), group HF (fully sintered and etched with 48% hydrofluoric acid solution at 100°C for 25min), and group Si (coated with silica particles and then fully sintered). The mean value of surface roughness was evaluated before further treatment. Resin stubs (3.6mm in diameter and 3mm in height) were adhered and light cured on each zirconia disc after the application of a silane coupling agent. In each group, all the samples were further divided into three subgroups with each n=12, one for the measurement of initial adhesion strength (shear bond) value and the other two were tested after thermal cycling for 10,000 and 20,000 cycles, respectively. The results were analyzed with two-way ANOVA and Turkey HSD (p<0.05). XRD technique was utilized in the examination of zirconia surface crystallinity. The morphological appearance of zirconia surface after surface treatment was observed with SEM. ResultsThe control group showed the lowest initial shear bond strength (SBS) value (16.8±2.4MPa) and did not survive the aging treatments. All the investigated surface treatments improved resin zirconia bond strength significantly, the group S displaying the highest initial value of 25.1±2.7MPa. However, the highest resistance to the aging effects of thermal cycling was found in group Si. It was further shown in the XRD examination that only the grit-blasting caused the crystalline transformation from tetragonal phase to monoclinic phase (T→M). On the other hand, such a phase transformation could not be detected in all the other four groups. SignificanceResin zirconia adhesion could be effectively improved by both HF etching and silica coating on zirconia surface, without leading to a T→M crystalline phase transformation.

Effect of Nanofiller Technology on Surface Properties of Nanofilled and Nanohybrid Composites

Context: Nanocomposites are becoming popular today because of the manufacturers claiming high surface smoothness and good abrasion resistance properties thus improving the longevity of the restoration. Aims: This in vitro study was carried out to investigate the effect of nanofillers on surface roughness and abrasion resistance of nanofilled composite- Filtek Z350 (3M ESPE) and nanohybrid composite- Tetric N Ceram (Ivoclar Vivadent) after polishing and abrasion. Methods and material: A total of fifteen disc specimens of each category of material were prepared under standardized conditions. The discs were finished and polished according to manufacturer's instructions. The samples were examined for surface roughness using Mahr Perthometer M2 followed by scanning electron microscope examination. In order to assess the performance of the materials in simulated oral conditions the samples were then subjected to toothbrush-dentifrice abrasion and the resultant surface roughness was compared for both the materials. Statistical analysis: Mean value of surface roughness was calculated for both the groups from Ra values before and after toothbrush- dentifrice abrasion followed by calculation of Standard deviation (SD). Paired-t test was then applied to compare the surface roughness values before and after toothbrush-dentifrice abrasion within the same group. Results: Initially the surface roughness of Filtek Z350 were found to be superior to Tetric N Ceram but after subjecting to toothbrush dentifrice abrasion Tetric N Ceram showed greater increase in surface roughness as compared to Filtek Z350. The difference was found to be statistically significant. Conclusions: Nanofiller type, size and distribution significantly influence the surface properties of composites. Though nanohybrid composite showed a better initial surface polish but nanofilled composite showed a better abrasion resistance.