Effect of hydrogen peroxide versus charcoal-based whitening mouthwashes on color, surface roughness, and color stability of enamel.

BACKGROUND: Patients tend to favor the whitening mouthwashes as they are easily applied and affordable. This study aimed to evaluate the effect of hydrogen peroxide versus charcoal-based whitening mouthwashes on color, surface roughness, and color stability of enamel. In the current study, the whitening mouthwashes used have the ability to stop future stains due to their white seal technology. METHODS: A total of 21 permanent central incisor teeth extracted for periodontal reasons were used in the present study. Teeth roots were sectioned and crowns were mounted in self-cured acrylic resin blocks. The specimens were randomly divided into three groups (n = 7) according to the tested whitening mouthwash: Control group ? DW" (Distilled water), ?OW" group: Peroxide-based mouthwash (Colgate Optic White) and ?CP" group: Charcoal-based mouthwash (Colgate® Plax Charcoal). Regarding ?OW" and ?CP" groups, the specimens were immersed in 20 ml of the tested mouthwash in each corresponding group for 1 min twice daily (morning and evening) for a total of 12 uninterrupted weeks. Color change was assessed using VITA Easyshade spectrophotometer and surface roughness (Ra) was measured using a white light interferometer. The specimens were stained using black tea solution and color was measured after 24 h of immersion for assessment of color stability. RESULTS: Color change results revealed that both whitening mouthwashes were able to restore color comparable to the control group with no significant difference between them. Regarding surface roughness, the control group showed the highest mean Ra value, followed by ?OW" group while ?CP" group showed the lowest mean Ra value. While color stability after staining, the control group showed a significantly higher value than the ?CP" and ?OW" groups. CONCLUSION: Hydrogen peroxide and charcoal-based whitening mouthwashes improve the color of enamel with no adverse effect on the surface roughness. Both whitening mouthwashes were beneficial to maintain the color after staining and prevent future enamel stains.

Active Magnesium Boride/Alginate Hydrogels Rejuvenate Senescent Cells.

The clearance of senescent cells may be detrimental to low cell density diseases, such as intervertebral disc degeneration (IVDD), and rejuvenating these cells presents a formidable obstacle. In this study, we investigate a mild-alkalization strategy employing magnesium boride-alginate (MB-ALG) hydrogels to rejuvenate senescent cells associated with age-related diseases. MB-ALG hydrogels proficiently ensnare senescent cells owing to their surface roughness. The hydrolysis of MB-ALG hydrogels liberates hydroxide ions (OH-), effecting a transition from an acidic microenvironment (pH ∼ 6.2) to a mildly alkaline state (pH ∼ 8.0), thereby fostering senescent cell proliferation via activation of the PI3K/Akt/mTOR pathway. Additionally, H2 aids in ROS clearance, which reduces cellular oxidative stress. And, Mg2+ rejuvenates senescent cells by inhibiting Ca2+ influx and fine-tuning the sirt1-p53 signaling pathways. Both in vitro and in vivo experiments conducted on rat intervertebral discs corroborate the sustained antisenescence and rejuvenation properties of MB-ALG hydrogels, with effects persisting for up to 12 weeks postoperation. These discoveries elucidate the role of mild-alkalization in dictating cellular destiny and provide key insights for addressing age-related diseases.

Energy efficiency identification and surface roughness prediction using cutting force signal for computer numerical controlled machine systems.

The energy efficiency identification of machining process plays an indispensable part in achieving energy-efficient manufacturing and improving energy utilization as well as productivity and surface quality. However, there is a great difficulty to track energy efficiency in real-time based on one kind of traditional power signal. Because energy consumption is affected by many factors such as machine tool current performance, tool wear conditions and cutting parameters selection. This paper puts forward an energy efficiency recognition method as well as surface roughness prediction model based on the cutting force signals. The CEEMDAN (Complete Ensemble Empirical Mode Decomposition with Adaptive Noise) algorithm is employed to decompose the cutting force signal into multiple IMF (intrinsic mode function) components; and characterization of energy efficiency of machining process is recognized through proportion of components based on PCA-Fast ICA algorithm. Then, a surface roughness prediction model is proposed using support vector regression (SVR) based on specific cutting energy consumption (SCEC). The orthogonal test is designed considering spindle speed, feed rate, depth of cutting and width of cutting in 3 levels to obtain the influence degree of cutting parameters on cutting force, specific energy consumption, and the surface roughness. The energy efficiency of 27 group experiments is classified into high, medium and low levels according to energy efficiency value. Finally, using the data of orthogonal test, energy efficiency state was identified. The result show that time-frequency of cutting force signals for high, medium and low energy efficiency could be extracted, and the average absolute error of surface roughness predict is 0.058. That illustrated that the proposed method could meet the industry requirement for energy efficiency monitoring and surface roughness prediction to achieve sustainable manufacturing.

Qualitative surface roughness of lithium disilicate endo-crown for pulpotomized primary molars.

Rehabilitation of pulpotomized primary molars with an appropriate restoration is essential for recovering function and safeguarding the durability of the treatment. This study aimed to assess and compare the surface roughness of stainless steel (ST) crowns, zirconia (ZR) crowns, fiberglass (FG) crowns, and lithium disilicate (LD) endo-crowns as a restoration for pulpotomized primary molars also, evaluating the surface roughness of their antagonists. Sixty pulpotomized primary mandibular first molars were used for qualitative surface roughness evaluation and divided into four groups (n = 15/group) according to the crown type (group-ST, group-ZR, group-FG, group-LD). While the other sixty sound, unprepared primary maxillary first molars were used for evaluation of their surface roughness against the tested crowns. Specimens' preparation and cementation were carried out according to each crown type and manufacturer's instructions. The surface roughness was done using a two-body wear test. The data were statistically analyzed. All tested crowns showed an increased change in surface roughness, except group-ZR, which had the least change in surface roughness after mechanical wear with no statistically significant difference(P = 0.681). All crown types significantly increased the surface roughness of their antagonists after mechanical wear, except group-ST which showed insignificant affection (p ≥ 0.05). Zirconia crowns and lithium disilicate endo-crowns had the least change in surface roughness compared to other groups while SSCs showed the least tooth loss in the antagonist enamel.

Comparison of polishing methods for two types of monolithic all-ceramic crowns after occlusal adjustments: Polishing paste versus glazed porcelain.

This study compared the effects of two surface preparation methods on two types of zirconia. Immediately prior to the placement of a monolithic zirconia crown, its morphology may be modified using a rotary cutting instrument for occlusal adjustments. The crown surface is scratched during the grinding process and, thus, requires polishing. Simplified zirconia crowns of 3Y and 5Y were fabricated and used as specimens. The surface roughness and gloss of the occlusal surfaces of specimens were measured and compared when a polishing compound was used after polishing points and when a silica-based coating was sintered. No significant differences were observed in surface roughness between 3Y and 5Y zirconia. The use of polishing compounds was effective because polishing points alone only resulted in a level of surface roughness that may cause wear on antagonist teeth. Although the silica-based coating improved surface properties, the polishing compound more effectively improved surface roughness.

Surface roughness of different types of resin composites after artificial aging procedures: an in vitro study.

BACKGROUND: The temperature changes, chemical agents, and brushing activity that resin composite restorations are exposed to in the oral environment can cause changes in surface roughness. In this study, the aim was to investigate in vitro the clinical one-year surface roughness changes of different types of composites (flowable or conventional) from the same companies by subjecting them to immersion in solutions, brushing, and thermal cycling procedures to simulate intraoral conditions. METHODS: Four different resin composite brands were included in the study using both their conventional (Charisma Smart, 3M Filtek Ultimate Universal, Omnichroma, Beautifil II) and flowable resin composites (Charisma Flow, 3M Filtek Ultimate Flowable, Omnichroma Flow, Beautifil Flow Plus F00), giving 4 groups with 2 types of resin composite in each. 40 samples were prepared for each group/resin type, for a total of 320 samples. After initial surface roughness measurements by a mechanical profilometer, the samples were divided into 4 subgroups (n = 10) and immersed in solutions (distilled water, tea, coffee, or wine) for 12 days. The samples were then subjected to 10,000 cycles of brushing simulation and 10,000 cycles of thermal aging. Surface roughness measurements were repeated after the procedures. For statistical analysis, the 3-way analysis of variance and the Tukey test were used (p < 0.05). RESULTS: It was concluded that composite groups and types had an effect on surface roughness at time t0 (p < 0.001). At time t1, the highest surface roughness value was obtained in the Beautifil-conventional interaction. When the surface roughness values between time t0 and t1 were compared, an increase was observed in the Beautifil II and Beautifil Flow Plus F00, while a decrease was observed in the other composite groups. CONCLUSION: Composite groups, types, and solutions had an effect on the surface roughness of resin composites. After aging procedures, it was concluded that the Beautifil group could not maintain the surface structure as it exceeded the threshold value of 0.2 µm for bacterial adhesion.

Rheological Behavior of an Aqueous Suspension of Oxidized Carbon Nanohorn (CNHox).

Oxidized carbon nanohorn (CNHox) a carbon nanomaterial that has attracted attention due to its unique material properties. It is expected to be applied in various areas like cancer treatment, gene-expression technology, fluids with high thermal conductivity, lubricants, and so on. While the rheological measurements of suspensions provide information on the effective size and interactions of suspended particles, the rheological behaviors of aqueous suspensions of CNHox have never been systematically investigated. To clarify the rheological behaviors of aqueous suspensions of CNHox, their viscosity and dynamic viscoelasticity were measured with changing particle concentration and salt concentration. The viscosity of a CNHox suspension showed yield stress at low shear rates and showed shear-thinning behavior with increasing shear rates. The viscosity of 5 weight % CNHox suspensions was comparable to that of 60 weight % silica suspensions. This high viscosity at a low CNHox concentration is probably due to the porous structure and large effective volume of the CNHox particle. The estimated effective volume of CNHox calculated by the Krieger-Dougherty equation was 18.9 times larger than the actual volume calculated by the mass concentration and density. The dependence of rheological behavior of the CNHox suspension on salt concentration was weak compared to that of the colloidal silica suspension. This weak dependence on salt concentration may be due to the roughness of the particle surface, which would weaken the effect of electric double-layer interactions and/or van der Waals interactions between particles. These rheological behaviors of the aqueous suspension of CNHox shown in this research will be useful in efforts to improve the efficiency of its utilization for the various applications.

Evaluation of Surface Roughness of Translucent Zirconia After Applying Nd:YAG and CO2 Lasers: An In Vitro Study.

BACKGROUND AND OBJECTIVES: Surface roughness is one of the most important factors that play an important role in increasing the connection between the surface of the tooth and the applied restoration. Due to the increased interest in zirconia and the improvement of its mechanical and aesthetic properties, studies have increased that work to improve and increase its surface roughness so that it can be used as a veneer in the future. This study aims to compare the effect of two types of lasers on the surface of highly transparent zirconia to evaluate the surface roughness resulting from the two techniques. METHODOLOGY: The study sample consisted of 20 ceramic cubes made of translucent zirconia (DD cubeX2, Dental Direct, Germany). It was made using a CAD-CAM Zircodenta device (Imes-Icore, Germany) and a zirconia sintering furnace (Imes-Icore, Germany). The study sample was divided into two groups; the first group consisted of 10 cubes exposed to Nd:YAG laser and the second group consisted of 10 discs exposed to continuous wave CO2 laser. The surface roughness test was conducted for the study samples in each of the groups using a surface roughness tester. Data were collected and analyzed using SPSS v25 software. RESULTS: The surface roughness was measured and its mean was 1.208±0.22 in the Nd:YAG laser group and 0.809±0.21 in the CO2 laser group. There was a significant difference between the study groups according to the independent sample T-test. CONCLUSION: This study concluded that the Nd:YAG laser surface roughens of zirconia is greater than the continuous wave CO2 laser, with a substantially significant difference.

Bond strength and surface roughness assessment of novel antimicrobial polymeric coated dental cement.

Resin cement integrated with zein-incorporated magnesium oxide nanoparticles has previously been found to inhibit oral microbes and decrease bacterial biofilm. However, the bond strength and surface features of this biomaterial have yet to be investigated. The objective of this study was to evaluate the shear bond strength, mode of fracture, and surface roughness of resin cement modified with zein-incorporated magnesium oxide nanoparticles. Characterization of the cement was performed by X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. 126 human teeth were divided into 3 groups and cemented to lithium disilicate ceramic using resin cement with zein-incorporated magnesium oxide nanoparticles at concentrations of 0%, 1%, and 2% (n = 42). 21 samples of each group were subjected to the shear bond strength test, while the other 21 underwent thermocycling for 10,000 cycles before the test, after which all samples were evaluated for the mode of fracture. To assess surface roughness, resin cement disks were analyzed by a profilometer before and after undergoing thermocycling for 10,000 cycles. The shear bond strength of the cement with 1% and 2% nanoparticles was significantly higher than the control before thermocycling. The mode of fracture was found to be mainly adhesive with all groups, with the unmodified cement presenting the highest cohesive failure. There was no significant difference in surface roughness between the groups before or after thermocycling. The addition of zein-incorporated magnesium oxide nanoparticles to resin cement improved or maintained the shear bond strength and surface roughness of the resin cement.

Effect of acidic media on surface characteristics of highly filled flowable resin-based composites: An in vitro study.

OBJECTIVE: To analyze and compare the impact of acidic media on the surface characteristics of highly filled flowable resin-based composites. MATERIALS AND METHODS: Two hundred fifty-six specimens were divided into four groups: GUF (G-aenial Universal Flo), GUI (G-aenial Universal Injectable), TEF (Tetric EvoFlow), and FSF (Filtek Supreme Flowable Restorative). Surface characteristics were analyzed before (T0) and after specimens immersion in different media, such as gastric juice (GJ), fizzy drink (FD), citric juice (CJ), or artificial saliva (AS), for 9 h (T1) and 18 h (T2). The analyses included surface roughness (SR) measurements, where average roughness (Ra) was obtained, scanning electron microscopy (SEM) analysis, and surface hardness (SH) evaluation, with Vickers numbers (HV) reported. The differences in values among groups/subgroups within the same stage were assessed using two-way ANOVA and Tukey's post hoc test, whereas repeated measures ANOVA with Bonferroni post hoc test was performed to compare the changes in values through the stages. Data were presented as mean ± standard deviation (SD). RESULTS: At T0, GUI and GUF revealed lower Ra values (p < 0.05), more evenness in SEM micrographs, and higher HV values (p < 0.05) than FSF and TEF. At T1 and T2, specimens of all groups/subgroups demonstrated an increase in Ra and a decrease in HV compared with T0 (p < 0.05), as well as the changes in surface morphology on SEM micrographs. The lowest Ra and highest HV values were observed in GUI group, in contrast to FSF group, and in specimens immersed in GJ. CONCLUSIONS: GUI revealed lower SR and higher SH compared to GUF and FSF both before and after exposure to acidic media. The presence of acidic media, especially GJ, significantly increases SR and decreases SH of tested materials. CLINICAL SIGNIFICANCE: Information on the changes in the surface characteristics of highly filled resin-based composites after exposure to acidic media may be essential for the longevity of restorations like composite veneers fabricated from these materials.

Effect of Nanoscale Surface Roughness and Electron-Phonon Interaction on Vibrational Modes of Cadmium Telluride Using Resonant Raman Spectroscopy.

This study investigates the combined effects of nanoscale surface roughness and electron-phonon interaction on the vibrational modes of cadmium telluride (CdTe) using resonant Raman spectroscopy. Raman spectra simulations aided in identifying the active phonon modes and their dependence on roughness. Our results reveal that increasing surface roughness leads to an asymmetric line shape in the first-order longitudinal optical (1LO) phonon mode, attributed to an increase in the electron-phonon interaction. This asymmetry broadens the entire Raman spectrum. Conversely, the overtone (second-order longitudinal optical [2LO]) mode exhibits a symmetrical line shape that intensifies with roughness. Additionally, we identify and discuss the contributions of surface optical phonon mode and multiphonon modes to the Raman spectra, highlighting their dependence on roughness. This work offers a deeper understanding of how surface roughness and electron-phonon scattering influence the line shape of CdTe resonant Raman spectra, providing valuable insights into its vibrational properties.

An In Vitro Analysis of the Effects of Mouthwashes on the Surface Properties of Composite Resin Restorative Material.

BACKGROUND: Restorative composite resins have clinical prime importance in modern dental practice, but numerous factors influence their prognosis in the oral environment. Their interaction with oral care products, like mouthwashes, is one such factor. This study aimed to evaluate the quantifiable effects of different mouthwashes on the surface properties of the composite resin restorative material. METHODOLOGY: The method involved formulating 90 samples of nanohybrid composite resins (Medicept Dental India Private Limited, Mumbai, India). The samples were treated with 1% alcohol, without alcohol, and with a saline solution (control). Surface roughness (Ra values) and microhardness had been checked before and after an exposure period of 24 hours. Data were thus tabulated, and from that, average values of surface roughness and microhardness were derived. This data was analyzed using the IBM SPSS Statistics for Windows, V. 26.0 (IBM Corp., Armonk, NY). Analysis of variance (ANOVA) and a t-test were used to compare the means of the variables. The level of significance was fixed at p < 0.05. RESULTS: The surface roughness value was significantly highest in the ethanol-containing mouthwash-treated samples after 24 hours of exposure (p < 0.05). The microhardness was statistically lower in these samples (p < 0.05). CONCLUSION: These research data give quantitative information, however, about the mass effect of mouthwashes on the composite resin restorative material. The presented changes, which were illustrated by the values of surface roughness and microhardness, are drawing attention to the fact that a cautious approach must be taken in the recommendations for oral care in the provision of intensive treatments with restorative composite resins.

Evaluation of the Surface Roughness and Color Stability of Two Types of Milled Zirconia Before and After Immersion in Alcoholic Beverages: An In Vitro Study.

Objective This study aims to evaluate the effects of immersion in alcoholic beverages on the surface roughness and color stability of two types of milled zirconia. Materials and methods The sample size included 60 cuboid-shaped samples of two types of zirconia (Z1 and Z2), 30 in each group. Zirconia was milled and sintered at 1,500°C for eight hours. The samples were immersed in artificial saliva (control), red wine, and whiskey three times a day over a 30-day period. After each post-immersion cycle, samples were cleaned ultrasonically. Surface roughness and color parameters were measured using an atomic force microscope (AFM) and spectrophotometer before and after immersion. The collected data was organized into tables, and statistical analysis was conducted using the Statistical Package for the Social Sciences (SPSS) version 27 software (IBM SPSS Statistics, Armonk, NY). For surface roughness, a paired t-test was conducted, while for color change, one-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests were done. Results The mean values of pre- and post-immersion values reveal that whiskey causes the highest difference in surface roughness for Z1 (137.09 nm) and Z2 (86.15 nm) groups, while red wine causes maximum discoloration in both Z1 (2.41) and Z2 (1.94) groups. The paired t-test revealed significant surface roughness changes in Z1 with artificial saliva and red wine, while whiskey (p<0.05), although showing changes, lacked statistical significance (p>0.05). The whiskey group demonstrated a moderate linear association (0.599) between pre- and post-immersion values. For Z2, artificial saliva, red wine, and whiskey (p<0.05) induced statistically significant surface roughness alterations. ANOVA tests indicated significant color changes post-immersion in all three subgroups of Z1 and Z2 (p<0.05 for both). Tukey's HSD test showed significant differences between artificial saliva and red wine (p<0.05), as well as artificial saliva and whiskey (p<0.05) in Z1 and Z2. However, no significant difference was found between red wine and whiskey in both Z1 and Z2 groups (p>0.05). Conclusion Whiskey, red wine, and artificial saliva increased zirconia's surface roughness. Alcoholic solutions altered zirconia's colorimetric parameters, with no significant differences among them.

Optimization of machining parameters for turning operation of heat-treated Ti-6Al-3Mo-2Nb-2Sn-2Zr-1.5Cr alloy by Taguchi method.

TC21 alloy is a high-strength titanium alloy that has been gaining attention in various industries for its excellent combination of strength, toughness, and corrosion resistance. Given that this alloy is hard to cut material, therefore this study aims to optimize the process parameters of Turing this alloy under different conditions (i.e. as-received alloy, and heat-treated alloy). The L9 Taguchi approach-base orthogonal array is used to determine the optimum cutting parameters and the least number of experimental trials required. The achievement of this target, three different cutting parameters are used in the experimental work; each cutting parameter has three levels. The cutting speeds are chosen as 120, 100, and 80 m/min. The feed rates' values are 0.15, 0.1, and 0.05, mm/rev, and the depth of cut values are 0.6, 0.4, and 0.2 mm. After applying three steps of heat treatment (First step: is heating the sample to 920 °C for 1 h then decreasing to 820 °C also for 1 h, second step: cooling the sample to room temperature by water quenching (WQ), the third step: holding the sample at 600 °C for 4 h (Aging process)). The results revealed that the triple heat treatment led to the change in the microstructure from (α + ß) to (α + ß) with secondary α platelets (αs) formed in residual ß matrix leading to a decreased surface roughness by 56.25% and tool wear by 24.18%. The two most critical factors that affect the tool insert wear and surface roughness are the death of cut and cutting speed, which contribute 46.6% and 46.7% of the total, respectively. Feed rate, on the other hand, has the least importance, contributing 20.2% and 31.9% respectively.

The effect of whitening toothpastes on the color stability and surface roughness of stained resin composite.

BACKGROUND: This study aimed to investigate the effect of whitening toothpastes on the color stability and surface roughness of resin composites stained with coffee and cigarette smoke. METHODS: Seventy-two disk-shaped specimens (6 × 2 mm) of suprananohybrid resin composite were randomly divided into two groups and exposed to coffee and cigarette smoke (n = 36). After staining, the samples randomly divided into four groups according to whitening toothpastes and were brushed for 4 min: Opalescence Whitening (OW); Colgate Optic White (COW); Curaprox Black is White (CPX) and, distilled water (control) (n = 9). Color was measured with spectrophotometer at the initial, after staining, and after brushing, and surface roughness was measured with profilometer at the initial and after brushing. A surface morphology analysis was examined using scanning electron microscopy and atomic force microscopy. The obtained data were statistically analyzed. (p < 0.05). RESULTS: Cigarette smoke caused a significantly higher color change than coffee in the resin composite (p < 0.05). Brushing with hydrogen peroxide and silica-containing whitening toothpaste showed significant differences in color change (p < 0.05). The lowest whitening effect was found in activated charcoal-containing toothpaste. While all toothpastes increased the degree of surface roughness of resin composites, the highest roughness was caused by whitening toothpastes containing activated charcoal. (p < 0.05). CONCLUSIONS: The color stability and surface properties of resin composites can be affected by brushing them with whitening toothpaste. The utilization of whitening toothpaste containing hydrogen peroxide can be considered a safe method for increasing the whiteness of discolored resin composites.

Prolonged Lifespan of Superhydrophobic Thin Films and Coatings Using Recycled Polyethylene.

High-density polyethylene (HDPE) waste poses a significant environmental challenge due to its non-biodegradable nature and the vast quantities generated annually. However, conventional recycling methods are energy-intensive and often yield low-quality products. Herein, HDPE waste is upcycled into anti-aging, superhydrophobic thin films suitable for outdoor applications. A two-layer spin-casting method combined with heating-induced crosslinking is utilized to produce an exceptionally rough superhydrophobic surface, featuring a root mean square (RMS) roughness of 50 nm, an average crest height of 222 nm, an average trough depth of -264 nm, and a contact angle (CA) of 148°. To assess durability, weathering tests were conducted, revealing the films' susceptibility to degradation under harsh conditions. The films' resistance to environmental factors is improved by incorporating a UV absorber, maintaining their hydrophobic properties and mechanical strength. Our research demonstrates a sustainable method for upcycling waste into high-performance, weather-resistant, superhydrophobic films.

The effect of detox solution on color stability, roughness, and microhardness of monochromatic universal composite resins.

BACKGROUND: Currently, the advantages of monochromatic universal composite resin restorative materials have increased their use in dentistry. Accordingly, the optical, surface and mechanical properties of these materials have become more important. This study aimed to evaluate the effect of detox solution on discoloration, surface roughness (SR), and microhardness of different monochromatic universal composite resins (Omnichroma [O], Zenchroma [Z], Vittra [V], and Charisma Diamond One [CDO]). Another aim of this study was to evaluate the monomer conversion degree (DC) of the materials. METHODS: A total of 80 specimens were prepared to evaluate the materials (n = 10). After the initial measurements, the specimens were immersed in a red detox solution for 21 days. Statistical data analysis was performed using one-way ANOVA and Tukey's multiple comparisons. RESULTS: The ∆E values of Z were highest on the 21st day. There was an increase in the SR values of the materials immersed in the detox solution. On the 21st day, top surface microhardness of O was lower than the other materials. There was no statistically significant difference at DC values among material groups. CONCLUSIONS: The use of detox solutions for a commercially recommended period of 21 days is suggested. However, this usage period can cause discoloration in restorative materials. Furthermore, especially in the initial one-week period, detox solution may have a negative impact on the microhardness of the materials. In light of all these data, we recommend the cautious use of detox solutions to prevent adverse effects on restorative materials.

A Comparative In Vitro Physicochemical Analysis of Resin Infiltrants Doped With Bioactive Glasses.

Objective This study aimed to investigate the longevity and effectiveness of bioactive glass (BAG)-based dental resin infiltrants. Materials and methods The three types of BAG - 45S5 bioglass (RIS), boron-substituted (RIB), and fluoride-substituted (RIF) - were incorporated with photoinitiated dimethacrylate monomers to create experimental resin infiltrants. ICON® (CN; DMG-America, Ridgefield Park, NJ) and pure resin (PR) were used as control groups in this study. Disc-shaped samples were prepared for the experimental and control groups. The samples were challenged with the pH cycle and immersed in the artificial saliva for 30 days. On Day 0 and Day 30, the pH cycle and artificial saliva immersion, Vicker's microhardness, surface roughness, and surface morphology were investigated. Results The RIF group's disc samples showed the highest Vicker's microhardness values (78.20 ±0.06) on Day 30 of artificial saliva immersion, whereas the CN group's values were the lowest (55.99 ±0.24). Following the pH cycling, the RIF displayed the highest hardness (64.15 ±1.89) whereas the CN group's values were the lowest (33.47 ±1.28). Regarding surface roughness, on Day 30, the RIB resin group exhibited the highest (1.14 ±0.001 µm). In contrast, the CN resin showed the lowest (1.07 ±0.06 µm) values, while immersed in the artificial saliva solution. In the same duration of time, in the pH cycling solution, PR showed the least (0.85 ±0.89 µm), while RIF showed the highest roughness value (0.94 ±0.54 µm). Morphological analysis revealed that following the artificial saliva immersion, the RIB, CN, and PR exhibited smoother surfaces compared to the RIS and RIF groups. However, when immersed in the pH cycling solution, RIB and RIF showed more resistance against acid attack. Conclusions Our results revealed that the experimental resin groups performed much better than the commercial resin infiltrants following artificial saliva and pH cycling challenges.

[Surface roughness of two composite resins after immersion in soda drinks: in vitro study]. / Rugosidad superficial de dos resinas compuestas después de la inmersión en bebidas gaseosas: estudio in vitro.

Objective: Compare the surface roughness of two composite resins after immersion in carbonated beverages. Materials and methods: 160 resin discs (6 x 2 mm) were divided into 8 groups (n=20 per group) according to type of resin (Filtek™ Z350 XT® and Palfique LX5®) and type of immersion in beverages (distilled water, Coca Cola®, Inca Kola® and Kola Escocesa®. The immersions were carried out under a structured cycle: 4 immersions a day for 5 days, intermediate storage in distilled water and overnight incubation for 8 h at 37°C. The measurements with the roughness meter were evaluated in three times: baseline, 7 and 14 days. The three-way Anova test was used at P<0.05. Results: Roughness showed differences only for the individual factors of time (P<0.000) and resin (P=0.000), and for the interaction time*drink (P=0.000) and resin*drink (P=0.003). Roughness was higher with Filtek Z350 XT® immersed with Inca Kola® (0.85 ± 0.37) than 14 days compared to other times (P=0.035) and with Palfique LX5 immersed in Coca Cola® at 7 days (1.61 ± 0.42) and in Inca Kola® at 14 days (1.66 ± 0.56) compared to distilled water (P<0,05). Conclusion: Surface roughness was affected by the type of resin, the type of soft drink and the immersion time. The roughness was greater with the Palfique LX5® nanohybrid resin, the Inca Kola® drink and after 14 days of immersion.

Effect of beverages, denture cleanser and chlorhexidine gluconate on surface roughness of flexible denture base material: an in vitro study.

Purpose: The purpose of the study was to evaluate and compare the effect of beverages, denture cleanser and chlorhexidine gluconate solution on surface roughness of flexible denture base material. Materials and methods: Fifty flexible denture base resin specimens measuring 50±1mm in diameter and 0.5±0.05 mm in thickness were fabricated. The specimens were divided into five groups each containing ten specimens. The specimens were immersed in distilled water (Control group A); hot coffee (Group B); cold beverage (Group C); sodium perborate containing denture cleanser (Group D) and 2% chlorhexidine gluconate solution (Group E). The specimens were immersed for 10 min daily in mentioned solutions for up to 60 days. Surface roughness (Ra) was evaluated on the 1st, 20th and 60th day with the help of atomic force microscope. The statistical analysis was done using two-way ANOVA and Tukey's Post hoc test. Results: The two- way ANOVA revealed that the average Ra values varied significantly depending on the type of solution used for immersion (p<0.001) and the duration of immersion (p<0.001). Variation in surface roughness with cold beverage was highest (p=0.001). On the 60th day the surface roughness of flexible denture base resin material was higher with cold beverage (0.184 µm) and denture cleanser (0.203 µm) than that of distilled water (0.052 µm) hot coffee (0.030 µm) and 2% chlorhexidine gluconate (0.068 µm). Conclusion: Exposure to cold beverage, which was acidic in nature and peroxide containing denture cleanser, produces much rougher surface in the thermoplastic polyamide flexible denture base resin specimens.