Non-contact Profilometer Research Articles

Nanocomposites soft and hard denture liners containing ZrO2 nanoparticles: An in vitro evaluation of surface roughness and Candida albicans adhesion.

To investigate the impact of zirconium dioxide nanoparticles (nano-ZrO2) addition to hard and soft liners on the surface roughness and Candida albicans adhesion. Nano-ZrO2 was added to hard and soft chairside reline material in two concentrations (2%wt. and 4%wt.) while an unmodified group of each liner acted as a control, (n=10). Disc-shaped (10×1.3mm) specimens of hard denture reline (N=60) and soft denture reline (N=60) materials were prepared (30/test). A noncontact profilometer was used for surface roughness measurement. A colony-forming unit (CFU/mL) was used to evaluate Candida albicans adhesion. Data was analyzed using ANOVA and a post hoc Tukey's test (α=0.05). No significant change in surface roughness was observed with nano-ZrO2 addition; however, the control groups showed the highest value while 2% nano-ZrO2 showed the lowest value. In comparison to the control groups, nano-ZrO2 addition to the hard and soft liners significantly reduced Candida albicans adhesion (p<0.001), regardless of the concentration. Incorporating nano-ZrO2 into hard and soft liner had no effect on surface roughness while its addition reduced Candida albicans adhesion. Using chairside soft and hard liners containing nano-ZrO2 is recommended to reduce the incidence of denture stomatitis (DS) among denture wearers.

The Staining Susceptibility and Surface Roughness of Teeth Restored by Microabrasion and Resin Infiltration: An In Vitro Study.

This study assessed the susceptibility to staining and surface roughness of white-spot lesions (WSLs) treated with resin infiltration (RIT) and microabrasion (MA) under simulated aging through thermocycling in red wine. Seventy-eight extracted human premolars with artificial WSLs were divided into three groups: untreated WSLs (control), RIT-treated (ICON®, DMG), and MA-treated (Opalustre®, Ultradent). Each group was further split: one subgroup immersed in artificial saliva and the other thermocycled in red wine. The color change (∆E) and surface roughness (Ra) were measured before and after staining using a spectrophotometer and a non-contact profilometer. Thermocycling in red wine increased color change (ΔE) across all groups, with the highest values observed for MA (43.94 ± 3.57), followed by RIT (31.40 ± 4.89). Surface roughness (Ra) was highest in untreated WSLs (0.61 ± 0.18 µm) and lowest in RIT (0.15 ± 0.03 µm). While RIT and MA similarly improved WSL appearance, RIT exhibited superior smoothness. These findings suggest that RIT provides a more durable surface with reduced roughness, although staining susceptibility remains comparable to MA. Moderate positive correlation was found between ΔE and Ra, indicating that roughness is one of the factors influencing color changes.

Evaluation of the Effects of Thermal Aging on the Surface Roughness of Novel Tooth-Colored Restorative Materials.

Background: The development of composite resins has led to novel materials aimed at improving restoration longevity. This study evaluates the surface roughness of four tooth-colored restorative materials after thermal aging. Methods: Eighty Class V preparations were restored with Admira Fusion, Beautifil II, Equia Forte HT, and Filtek. The samples underwent thermocycling, and their surface roughness was measured with a 3D non-contact profilometer at 24 h post-restoration and after simulation for 1, 3, and 5 clinical years. Results: Equia Forte HT showed the highest surface roughness and significant surface deterioration over time, while Admira Fusion maintained the lowest roughness across all intervals. Conclusions: Admira Fusion, Filtek, and Beautifil II demonstrated superior surface stability, with Equia Forte HT showing the least favorable performance.

Surface Roughness and Color Stability of Newly Developed Resin Composites With Color Adjustment Potential After Immersion in Staining Solutions.

The aim of this this study was to evaluate the surface roughness and color stability of resin composites (RCs) with color adjustment potential (CAP): Omnichroma (OM), (Tokuyama Dental, Tokyo, Japan); Neo Spectra ST (NS) (Dentsply Sirona, York, PA,USA); and Charisma Diamond One (CD) (Kulzer, Hanau, Germany), compared to a conventional RC, Filtek Z350XT (FZ) (3M ESPE, St. Paul, MN,USA), after immersion in three staining solutions, cola, coffee, and black tea, with distilled water as a control. Forty specimens (8 mm diameter x 2 mm thickness) were prepared for each RC material and divided into subgroups (n=10/group) based on the immersion solution. Surface roughness was measured at baseline and after 21 days of immersion using a non-contact optical profilometer. Color change (ΔE00) was evaluated at baseline, 1, 7, and 21 days with a spectrophotometer. The results showed that FZ demonstrated the lowest surface roughness (0.14), significantly differing from that of the other RCs with CAP (p<0.05), while no significant differences in surface roughness were observed between RCs with CAP (p>0.05). There were no significant changes in surface roughness before and after immersion in various solutions. The results for color change (ΔE00) were statistically significant. Neo Spectra ST showed the lowest tendency for color change, while Filtek Z350XT displayed a moderate potential, and Omnichroma and Charisma Diamond One showed the highest potential for color change.

Flexural strength, surface roughness, and color stability of various CAD-CAM denture teeth materials.

To assess the flexural strength (FS), surface roughness, and color stability of additive manufactured (AM) and subtractive manufactured (SM) denture teeth materials, as well as the effect of thermocycling on these properties. Eighty strips (20/material type; 64×10×3.3mm) and 60 discs (15/material type; 12×4mm) were fabricated from four different denture teeth materials (Straumann, Flexcera, Ivoclar, and Candulor). The specimens were divided into two subgroups (nonthermal cycled and 5000 thermal cycled,10 per subgroup), and subjected to a 3-point test for FS using a universal testing machine at a crosshead speed of 5.0mm/min. Surface roughness (Ra, µm) and color differences (ΔE00) of disc specimens were measured before and after thermocycling using a noncontact optical profilometer and a spectrophotometer, respectively. The CIEDE2000 formula was used to calculate the color differences (ΔE00) before and after thermocycling. Data were analyzed using 2-way ANOVA followed by post hoc multiple comparison tests (α=0.05). There was no significant difference in flexural strength between nonthermal cycled SM materials (p=0.15), which were significantly higher than AM materials (p<0.001). The flexural strength values of all tested materials weresignificantly reduced after thermocycling (p<0.05). The material type had a significant effect on the Ra values (p<0.001), whereas thermocycling did not (p=0.81). After thermocycling, all materials exhibited color changes lower than the clinical perceptible threshold (ΔE00=2.7). Thermocycling decreased the FS of denture teeth materials manufactured with AM and SM, but did not affect the surface roughness. The FS values of SM groups were significantly higher than AM materials, irrespective of thermocycling. No clinically significant color changes of the denture teeth material were noted.

Effects of Finishing on Surface Roughness of Four Different Glass-Ionomer Cements and One Alkasite: In Vitro Investigation over Time Using Aging Simulation.

In 2017, Europe implemented a ban on amalgam restorations for children aged <15 years and for pregnant/breastfeeding women, highlighting the need for alternative filling materials exhibiting less surface roughness and enhanced longevity. This in vitro study aimed to examine the surface roughness variations of five amalgam-replacement materials across three time points and using six finishing methods: (1) no finishing (control), (2) Arkansas burs, (3) diamond burs, (4) tungsten carbide burs, (5) SofLex discs in descending grit size, and (6) coarse SofLex discs combined with silicone polishing. We prepared 960 samples. Each material group, i.e., Cention Forte (CNF), DeltaFil (DLF), Ketac Universal (KTU), IonoStar Molar (ISM), and Equia Forte HT (EQF), comprised 60 samples (n = 10 per finishing method) created using standardized 3D-printed metal molds. Surface roughness (Sa) was measured immediately after finishing, after 30 days of storage in distilled water, and after thermocycling (5000 cycles) using a non-contact profilometer. The results indicate that conventional and hybrid glass-ionomer cements have smoother surfaces than high-viscosity GICs. The DLF and CNF groups exhibited stable outcomes. These findings underscore the importance of selecting appropriate finishing methods based on the restorative material to minimize surface roughness.

Optical Studies of Silver Oxide Deposited Thin Films Using the RF Sputtering Technique

Background/Objectives: Silver Oxide is an efficient material because it is used in batteries. Apart from this, it is a moderate oxidizing agent in a variety of processes including the oxidation of aldehydes to carboxylic acids. The objective of the study is to synthesize silver oxide films by RF sputtering technique so that synthesized films can be inserted in the spectrophotometer for optical study. Methods: Silver Oxide films were deposited on Fluorine-doped Tin Oxide (FTO) glass using Radio Frequency (RF) sputtering method and annealed at 200 °C, for two hours, and then it was used in DK2 Ratio recording Spectrophotometer to analyze absorption and transmission data. Findings: The thickness of the films was measured using a non-contact optical Profilometer, in the range of (42– 660) nm. The films were subsequently exposed to optical characterization, revealing exceptionally low transmittance and high absorbance. The band gap is estimated to be 2.2 eV. The X-ray diffraction (XRD) studies reveal that the material is crystalline and Miller indices have also been determined. The morphology and topography of the thin films were analyzed using Field Emission Scanning Electron Microscope (FESEM) and the chemical composition was estimated using EDS. Novelty: The present work reveals that the optical properties are highly dependent on the thickness and the material distribution. The direct band gap energy is evaluated from the absorption spectrum which comes out to be 2.2 eV. The XRD spectra synthesized Silver Oxide films are crystalline in nature. Keywords: Silver Oxide, Band gap, XRD, FESEM

To investigate the effect of discharge energy and addition of nano-powder on processing of micro slots using EDM assisted µ-milling operation

ABSTRACT Micro-electric Discharge-Milling (µ-ED-M) is a non-contact process that uses an electrical spark to remove the material from a submerged workpiece with an electrode in a dielectric. The present paper focuses on optimizing process energizing (Capacitor, Voltage) and process stabilizing (Tool Travel Speed, Nano-Powder) parameters for controlling the size and surface characteristics of micro-crater. The present work focuses on the effect of nano-powder concerning dimensional aspects and surface characteristics at high and low capacitance levels. A µ-slot has been generated on the copper material by a tungsten carbide electrode. The experimentation is performed with two capacitor levels and three voltage and tool travel speed levels using full factorial design technique using with and without mixing of nano-powder in dielectric. The desirability functional multi-objective optimization approach is used to analyze the MRR, TWR, Width, and Depth. Field emission scanning electron microscopy (FESEM), non-contact optical profilometer, and x-ray diffraction (XRD) techniques are used to analyze the surface morphology of machined surfaces. The ANOVA is used to optimize the results; at low discharge energy, tool travel speed contributes 41% and promotes a higher thickness of recast layer 12.7 µm, whereas high discharge energy and nano-powder concentration contribute approx.—36% with 8.56 µm of recast layer.

Bacterial adhesion and surface roughness of particulate-filled and short fiber-reinforced composites.

The objective of the study was to assess the initial adhesion of Streptococcus mutans (S. mutans) and surface roughness of different particulate-filled (PFC) and short fiber-reinforced (SFRC) composites. Five PFC composites (CeramX Universal, Filtek Universal, Omnichroma, Tetric Prime and Venus Diamond) and four SFRC composites (everX Posterior, everX Flow Bulk, everX Flow Dentin and experimental packable SFRC) were tested in this study. A non-contact 3D profilometer was employed to assess the surface roughness (Ra) of the polished specimens (using 4000-grit abrasive paper). For the bacterial adhesion test, the specimens (n = 5/group) were immersed in a solution of S. mutans to facilitate initial adhesion. To determine the number of cells on the surfaces of the discs as colony-forming units (CFU), the vials holding the microbial samples were highly agitated using a vortex machine. Subsequently, the samples were diluted multiple times and anaerobically incubated for 48h at 37°C on Mitis Salivarius Agar plates (Difco) supplemented with bacitracin. Bacterial adherence assessment was performed using SEM. The data were analyzed using ANOVA. All tested PFC and SFRC composites showed similar adhesion of S. mutan. The lowest Ra values (0.26µm) (p < 0.05) were found in the flowable SFRCs (everX Flow Bulk & Dentin), while the highest values (p < 0.05) were observed in CeramX and everX Posterior (0.42µm). Experimental SFRC had comparable Ra value (0.38µm) than other commercial composites. The presence of short microfibers in the composite appeared to have no adverse effects on the initial adhesion of bacteria or the surface roughness.

The impact of Streptococcus mutans biofilms on the color stability and topographical features of three lithium disilicate ceramics.

Secondary caries around ceramic restorations is the most common reason for the replacement of fixed dental prostheses (FDPs). Therefore, it is important to examine the susceptibility of different ceramic materials to biofilm formation. This study aimed to evaluate biofilm development and associated roughness and color alterations in three lithium disilicate ceramics: Emax CAD (EC), Emax Press (EP), and LiSi Press (LP). Streptococcus mutans biofilms were grown on the three ceramics (n = 10 per group) for 7 days. Surface roughness values and color alteration were assessed before and after the biofilm using a non-contact profilometer and spectrophotometer, respectively. Biofilm growth was evaluated using colony-forming units (CFUs) and scanning electron microscope (SEM) images. The data were analyzed using one-way ANOVA and Tukey tests. There was a significant (p≤0.001) growth of S. mutans colonies on EC (6.75 ± 0.56) and EP (6.72 ± 0.54) specimens compared to LP, which showed no biofilm growth. The change in average surface roughness (∆Ra, nm) was significantly lower (p < 0.001) in the EC specimens (0.029 ± 0.003) compared to the EP (0.055 ± 0.012) and LP (0.041 ± 0.010). When the changes in the Rv and Rt values were investigated, no significant difference was observed among the groups. Following the biofilm challenge, the change in color (∆E00) was significantly lower (p = 0.005) in the LP group (1.68 ± 1.45) compared to the EC group (3.89 ± 1.50) and no significant difference was observed between the EP group (2.74±1.01) and the other two ceramics (p ≥ 0.05). LP ceramics exhibited superior resistance to S. mutans biofilm formation and associated changes in surface roughness and color compared to the Emax CAD and Emax Press ceramics. These findings suggest that the LiSi Press material may be more favorable to mitigate the risk of secondary caries.

The Micromechanical Properties and Surface Roughness of Orthodontic Retainer Wires-An In Vitro Analysis.

Despite the large variety of retainer wires available, no studies could be found comparing the micromechanical properties and surface roughness of different retainer wires. Such characteristics affect the survival of the fixed retainer in terms of both fracture resistance and resistance to debonding from the tooth. Therefore, the aim of the present study was to examine and compare those characteristics in popular retainer wires. six different popular orthodontic retainer wires were subjected to instrumental indentation based on the Oliver and Pharr method. The geometric surface structure was analysed using a non-contact profilometer. stainless steel wires had a higher hardness and a higher elastic modulus compared to titanium wires and white gold chain. The titanium wire and the white gold chain showed much more roughness than other wires. stainless steel wires are the most resistant, considering both the shape retention capacity and the ability to resist abrasive wear. The titanium wire showed the lowest hardness and, thus, the highest susceptibility to deformation. Bond-a-braid, Retainium and Orthoflex white gold are more resistant to fracture than other steel wires. Titanium wire and chain retainer wires have more roughness, which is a great advantage in terms of mechanical adhesion to composite materials.

A Comparative Evaluation of Surface Hardness and Nanomechanical Properties of Nickel-Titanium Orthodontic Wires: An In Vitro Study.

The study aimed to evaluate the influence of various surface coatings (epoxy, Teflon, and rhodium) on the surface roughness (SR) and nanomechanical characteristics of nickel-titanium (NiTi) archwires. The study compared these coated archwires to uncoated ones from a single manufacturer, which served as a control. There were 15 rectangular samples of four distinct archwires measuring 0.17 × 0.25. These were ultrasonically treated with an alkaline solution at 60°C for 15 minutes before being rinsed with distilled water to remove precipitates. With an orthodontic soft wire cutter, the straight buccal sections of coated and uncoated archwires were cut into 20 mm lengths. A three-dimensional optical noncontact surface profilometer evaluated the surface. Profilometers use contact scanning white light interferometry. Using the Vision64 software (Bruker Corporation, San Jose, CA), the profilometer's nanolens atomic force microscopy module has a completely automated turret with programmed X, Y, and Z motions. Images were taken in five random locations. Five average measurements matched specimen SR. A nanoindenter with a Berkovich diamond indenter measured nanohardness (NH) and elastic modulus (EM). The experimental results were analyzed using the Statistical Package for the Social Sciences software version 26.0 (SPSS Inc., Chicago, IL). To examine mean differences at 5% significance, analysis of variance and Tukey's post hoc test were applied for SR, NH, and EM. Wires coated with epoxy had the highest SR (1.499 ± 0.082), followed by Teflon (0.811 ± 0.023) and rhodium (0.308 ± 0.024). The SR of the control group was 0.289 ± 0.027. Significant differences in SR were found (p < 0.0001). Except for the comparison between rhodium and the control group (p = 0.684), all intergroup comparisons of SR showed significant differences (p < 0.0001). The rhodium-coated wires exhibited the highest NH (0.185 ± 0.014), and the epoxy group had the lowest (0.147 ± 0.017). Variations in NH were significant between the study groups (p < 0.0001). The epoxy, Teflon, and rhodium groups showed significant differences against the control group (p < 0.0001) in intergroup comparisons for NH. The Teflon group had the highest EM (5.367 ± 0.379), and the epoxy group had the lowest (5.012 ± 0.498). The EM of the control group was 56.946 ± 0.737. Results indicate considerable EM changes between the groups (p < 0.05). Comparisons between experimental and control groups showed significant differences (p < 0.0001). The study's findings indicate that the SR of rhodium-coated archwires is substantially comparable to that of uncoated archwires. However, Teflon-, rhodium-, and epoxy-coated archwires had significantly different NH and EM compared to uncoated ones. Further, uncoated archwires have higher NH and EM.

In vitro evaluation of the mechanical and optical properties of 3D printed vs CAD/CAM milled denture teeth materials

This laboratory research aimed to assess the Flexural strength, fracture toughness, Volumetric wear and optical properties of various recent 3D-printed denture tooth materials and compare them to CAD/CAM milled materials. Four 3D-printed denture tooth materials (Lucitone Tooth, OnX, Flexcera Ultra +, and VarseoSmile Crown Plus) and one CAD/CAM milled denture teeth material (Ivotion Dent) were used to fabricate fifteen specimens for each material (with total no. of 300 specimens). Tests were conducted according to ISO standards to assess flexural strength, fracture toughness, color staining, and volumetric wear. All materials were printed, washed, cured, or milled following the manufacturer’s instructions. Flexural strength and fracture toughness values were obtained by a universal testing machine. Volumetric wear was evaluated using a non-contact optical profilometer. Color stability outcomes were obtained via a spectrophotometer for determining L*a*b* values, with color change (ΔE2000) based on the CIEDE2000 formula. Data were analyzed using one-way ANOVA and Tukey post-hoc analysis (α = 0.05). All 3D-printed materials exhibited higher flexural strength values than the milled material (p < 0.05). For fracture toughness, two of the 3D-printed materials showed higher values than the milled material, while the other two had lower values. Insignificant variances in volumetric wear were detected between the materials (p > 0.05). Color staining results varied, with milled materials generally demonstrating better-staining resistance compared to the 3D-printed materials. 3D-printed denture tooth materials exhibit good mechanical and optical properties, presenting a cost-effective and efficient alternative to CAD/CAM milled materials for denture tooth fabrication.

Effect of solid lubricant additives on solid particle erosion characteristics of rigid and toughened epoxy resins

AbstractSolid lubricants are added to polymers to upgrade their tribological properties, especially in cases where adhesive and abrasive friction are valid. However, there are not enough studies on the effects of solid lubricants on particle erosion. This study investigated the effects on solid particle erosion behavior of three different well known solid lubricants (molybdenum disulfide, polytetrafluoroethylene, and graphite). These solid lubricants were added at three different ratios (5, 10, and 15 wt.%) to the two different type (rigid and toughened) epoxy resins. Garnet abrasive particles (180–400 μm) were blasted to the sample surface under 1.5 bar for 15 s to conduct solid particle erosion tests. The erosive wear mechanisms of neat and solid lubricant‐reinforced epoxy resins were investigated in relation to the epoxy type, solid lubricant type, and solid lubricant reinforcement ratio. Statistical analysis was performed according to response surface methodology to support the experimental results, and ANOVA tables were obtained. The wear and deformations that occurred on the surface after solid particle erosion were examined using a noncontact optical profilometer system and scanning electron microscopy, and a significant relationship was detected between the deformation on the surface and particle erosion. Analysis results showed that the factor causing the greatest erosion rate change was the epoxy resin type. Finally, it has been observed that all solid lubricants reduce the erosive wear resistance, and this resistance decreases as the weight ratio increases.Highlights Investigations were conducted into the erosion behavior of two types of epoxy resins: rigid and toughened. The toughened epoxy resin exhibited greater resistance to erosion. Although it has the same type of content, on average, rigid epoxy worn 2–4 times more than toughened epoxy. The effect of adding polytetrafluoroethylene tended to increase the erosion rate of both rigid and toughened epoxy resin less than that of other solid lubricants. Graphite particles increased the erosion rate of toughened epoxy by 1.5–3 times and that of rigid epoxy by 2–3 times, depending on the value of the reinforcement ratio. MoS2 increased the erosion rate of toughened epoxy by 1.5–3 times and that of rigid epoxy by 2–3 times. Using a noncontact optical profilometer (for investigating surface topography), it was proven that there is a significant relationship between the erosion rate and roughness characteristics. Wear mechanisms were identified by SEM analysis.

Study on the tribological performance of self-lubricating thrust ball bearings with different embedded features

PurposeThe purpose of this paper is to develop a new type of embedded solid self-lubricating thrust ball bearing for conditions where grease lubrication cannot be used and to analyze its tribological performance under different lubrication characteristics (lubrication position, width and filling amount).Design/methodology/approachLubrication parameters such as position (a), width (W) and filling amount (Q) were considered. Grooves were made on the raceway with a fiber laser and solid self-lubricating materials were applied through scraping. The frictional behavior of the new bearing was analyzed using a vertical test rig and the bearing’s surface topography was examined with a noncontact profilometer to study wear mechanisms.FindingsThe new inlay thrust ball bearings exhibited excellent lubrication effects and effectively controlled the temperature rise of the bearings. When a is 0 degrees, W is 0.5 mm and Q is 16 mg, the bearing experiences the least wear, and the friction coefficient and temperature are the lowest, measuring 0.001 and 41.52 degrees, respectively. Under the same experimental conditions, compared to smooth bearings without solid lubrication, the friction coefficient decreased by 96.88% and the temperature decreased by 59.74%.Originality/valueThis study presents a self-lubricating thrust ball bearing designed for conditions where grease lubrication is not feasible. A comprehensive investigation was conducted on its surface morphology, wear mechanisms and tribological performance. This work provides valuable insights into the research of self-lubricating thrust ball bearings.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0073/

High-temperature tribological behaviour and machining performance of self-lubricant CrAlNAg coatings for dry milling operations

Tribological and machining performance of CrAlNAg coatings having different Ag content tested against AISI 1045 medium carbon steel were assessed. Wear track was evaluated by scanning electron microscopy and energy dispersive spectroscopy. 3D topography of wear track and ball counterpart was determined by non-contact type profilometer. The formation of different oxide phases on track was confirmed using Raman spectroscopy. CrAlNAg9 and CrAlNAg12 coatings were found beneficial in reducing material adhesion from counterpart thus providing protective layers to counterpart, whereas small addition of Ag did not provide any improvement on CrAlN coating performance. CrAlNAg9 coated milling inserts demonstrated best results in terms of reduction in chip temperature (∼17.5 %), cutting forces, surface roughness (∼47 %) and chip thickness (∼12.7 %) compared to uncoated inserts.

Nanoparticle-Modified 3D-Printed Denture Base Resins: Influence of Denture Cleansers on the Color Stability and Surface Roughness In Vitro.

This study aimed to evaluate the influence of denture cleansers on the color, stability, and surface roughness of three-dimensional (3D)-printed denture base resins modified with zirconium dioxide nanoparticles (nano-ZrO2). A total of 440 specimens were fabricated using one heat-polymerized resin, and two 3D-printed resins (NextDent and ASIGA). According to the nano-ZrO2 content, the specimens for each resin were divided into five groups (0%, 0.5%wt, 1%wt, 3%wt, and 5%wt). Each concentration was divided into four subgroups (n = 10) based on the immersion solution (distilled water, sodium hypochlorite, Corega, and Fittydent) and immersion duration (360 and 720 days). The color changes (∆E00) and surface roughness (Ra, µm) of each specimen were measured at different time intervals (base line, 360 days, 720 days) using a spectrophotometer and a non-contact profilometer, respectively. The results were statistically analyzed using ANOVA and a post hoc Tukey's test (α = 0.05). Sodium hypochlorite showed the highest significant color change of all the denture base resins (p < 0.001). The average value of ΔE00 for sodium hypochlorite was significantly higher than the values for the other solutions (Fittydent, Corega, and water) (p < 0.001). Color stability was significantly affected by immersion time for all types of solutions except Corega (p < 0.001). All of the tested immersion solutions (distilled water, sodium hypochlorite, Corega, and Fittydent) showed a significant increase in the surface roughness of all the denture base resins (p < 0.05). Surface roughness was substantially increased by immersion time for all types of solution except Fittydent (p < 0.001). Denture cleansers can result in substantial color change and affect the surface roughness of unmodified and nanoparticle-modified denture base resins. Therefore, the selection of denture cleanser and appropriate types of material is critical for denture longevity.

Impact of Nanoparticle Addition on the Surface and Color Properties of Three-Dimensional (3D) Printed Polymer-Based Provisional Restorations.

This study aimed to evaluate and compare the impact of additives such as ZrO2 and SiO2 nanoparticles (ZrO2NP or SiO2NP) on the hardness, surface roughness, and color stability of 3D printed provisional restorations. Two hundred samples in total were printed using 3D printed resins (ASIGA, and NextDent). Each resin was modified with ZrO2NPs or SiO2NPs in two different concentrations (0.5 wt% and 1 wt%), while one group was kept unmodified (n = 10). Disc-shaped (15 × 2.5 mm) samples were designed and printed in accordance with the manufacturer's recommendation. Printed discs were evaluated for color changes through parameters CIELAB 2000 system (ΔE00), hardness using Vickers hardness test, and surface roughness (Ra) using a noncontact profilometer. After calculating the means and standard deviations, a three-way ANOVA and Tukey post hoc test were performed at α = 0.05. The addition of ZrO2NPs or SiO2NPs to ASIGA and NextDent resins significantly increased the hardness at a given level of concentration (0.5% or 1%) in comparison with pure (p < 0.001), with no significant difference between the two modified groups per resin type (p > 0.05). The highest hardness value was detected in 1% ZrO2NPs with 29.67 ± 2.3. The addition of ZrO2NPs or SiO2NPs had no effect on the Ra (p > 0.05), with 1% ZrO2NPs showing the highest value 0.36 ± 0.04 µm with NextDent resin. ZrO2NPs induced higher color changes (∆E00), ranging from 4.1 to 5.8, while SiO2NPs showed lower values, ranging from 1.01 to 1.85, and the highest mean ∆E00 was observed in the 1% ZrO2NPs group and NextDent resin. The incorporation of ZrO2NPs and SiO2NPs in 3D printed provisional resins increased the hardness without affecting the surface roughness. The optical parameters were significantly affected by ZrO2NPs and less adversely affected by SiO2NPs. Consequently, care must be taken to choose a concentration that will improve the materials' mechanical performance without detracting from their esthetic value.

The demineralization resistance and mechanical assessments of different bioactive restorative materials for primary and permanent teeth: an in vitro study

ObjectivesThis article examines the efficacy of two bioactive dental composites in preventing demineralization while preserving their mechanical and physical properties.Materials and methodsThe study compares Beautifil Kids and Predicta® Bioactive Bulk-Fill (Predicta) composites with conventional dental composite. Flexural strength and elastic modulus were evaluated using a universal testing machine. A pH-cycling model assessed the composites’ ability to prevent dentin demineralization. Color stability and surface roughness were measured using a spectrophotometer and non-contact profilometer, respectively, before and after pH-cycling, brushing simulation, and thermocycling aging.ResultsBeautifil Kids exhibited the highest flexural strength and elastic modulus among the materials (p < 0.05). Predicta demonstrated the highest increase in dentin surface microhardness following the pH-cycling model (p < 0.05). All groups showed clinically significant color changes after pH-cycling, with no significant differences between them (p > 0.05). Predicta exhibited greater color change after brushing and increased surface roughness after thermocycling aging (p < 0.05). While Beautifil Kids had higher surface roughness after pH-cycling (p < 0.05).Discussion/ConclusionBioactive restorative materials with ion-releasing properties demonstrate excellent resistance to demineralization while maintaining mechanical and physical properties comparable to the control group.

The effect of beverage temperature on the surface roughness, microhardness, and color stability of the monoshade composite resin: An in vitro study

ObjectiveThis study assessed the impact of beverage temperature on the surface roughness, microhardness, and color stability of monoshade composite resin. Materials and MethodsA batch of 70 monoshade composite resin specimens manufactured by Charisma Diamond ONE (Kulzer, Hanau, Germany) was prepared. Initial readings for surface roughness, microhardness, and color were recorded. The specimens were then divided into seven groupings of ten each: Distilled water (control group), Nescafe coffee at 70 °C and 5 °C, Arabic coffee at 70 °C and 37 °C, and cola at 7 °C and 24 °C. These samples underwent 30-min daily immersion in their respective beverages for a duration of 30 days. Final measurements were then taken. A non-contact profilometer was used for measuring surface roughness, a Vickers microhardness machine from Contour GT-I (Bruker Nano GmbH, Berlin, Germany) for microhardness, and a Color-Eye 7000A Spectrophotometer (X-Rite, GretagMacbeth, Michigan USA) for color stability. Statistical analyses, including repeated measure ANOVA for microhardness, roughness, and color, were executed using SPSS version 23. ResultsAll beverages led to changes in composite color and properties. Notably, coffee at 70 °C resulted in significant discoloration of the composite resin surface (p < 0.0001). The beverage that most affected the surface hardness and roughness of the monoshade composite resin was cola at 7 °C (p = 0.008) ConclusionThe inherent chemicals in beverages, coupled with their temperatures, can influence the composite properties of resin, specifically surface discoloration, hardness, and roughness. Clinicians may, therefore, consider instructing patients about the potential negative effects of these beverages.