Search Results (29)

Novel high-entropy perovskite oxide powders were synthesized using a sol-gel process. The B-site contained five cations: chromium, cobalt, iron, manganese, and nickel. The B-site cations were present on an equiatomic basis. The A-site cation was lanthanum, with calcium doping. The amount of A-site doping varied from 0 to 30 at%, yielding a composition of La_1−xCa_x(Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)O_3−δ. The resulting perovskite powders were pressurelessly sintered in air at 1400 °C for 2 h. Sintered densities were measured, and the grain structure was imaged via scanning electron microscopy to investigate the effect of doping. Samples were cut and polished, and their resistance was measured at varying temperatures in air to obtain the electrical conductivity and the mechanism that governs it. Plots of electrical conductivity as a function of composition and temperature indicate that the increased configurational entropy of the perovskite materials has a demonstrable effect. Full article

Background: Supragingival polishing is a crucial part of nonsurgical periodontal therapy. In recent years, air polishing has been used for this purpose, introducing different polishing powders. The purpose of the following study was to investigate the damage to the gingival margin during air polishing by an inexperienced operator. Methods: Five porcine models were polished by means of three different polishing powders: calcium carbonate, sodium bicarbonate, and erythritol. Their impact on the gingival margin was examined by means of histological and scanning electron microscopical observations and compared to healthy samples and samples polished with a polishing brush and paste. Results: The histological observations revealed superficial to minor lesions limited in the epithelium by all the groups tested. Both examination protocols demonstrated less invasiveness of the erythritol-based polishing powder. Conclusions: Within the limitations of the present study, it could be concluded that air polishing is a safe instrumentation method for periodontal therapy even in inexperienced hands when the exact protocol is followed. The erythritol-based polishing powder seems to provide less of an impact on the gingival margin. Full article

Surface roughness is a critical factor in restorative dentistry, as it influences both the esthetic and functional outcomes of dental materials. The choice of abrasive powders used during the air polishing of dental restorations can significantly impact the surface roughness, potentially affecting the longevity and performance of the restoration. This study aimed to compare the effects of three different air-polishing powders—sodium bicarbonate, erythritol, and glycine—on the surface roughness of a 3M Filtek™ Supreme XTE (3M St. Paul, Minnesota 55144-1000) United States composite resin and a Fuji™ IX glass ionomer cement. This study also examined how different application times (5 and 10 s) influenced these outcomes. Materials and Methods: An in vitro study was conducted using standardized blocks of 3M Filtek™ Supreme XTE composite resin and Fuji™ IX glass ionomer cement. Each material was treated with sodium bicarbonate, erythritol, and glycine at two different exposure times (5 s and 10 s) using a professional air-polishing device. Surface roughness (Ra) was measured before and after the treatments using a contact profilometer. The data were statistically analyzed using ANOVA and Tukey’s post hoc test to compare the mean roughness values among the different groups, with a significance level set at p < 0.05. Results: The results showed significant differences in surface roughness between the materials, powders, and application times. The composite resin exhibited lower roughness and variability compared with the Fuji™ IX, indicating a more uniform and predictable surface. Sodium bicarbonate produced the highest roughness values, particularly after 10 s of application, while glycine resulted in the lowest roughness with greater variability. Erythritol produced intermediate roughness with moderate variability. For the Fuji™ IX, sodium bicarbonate caused the greatest variability in roughness, while glycine produced the smoothest surfaces. The ANOVA results confirmed significant differences in mean roughness among the abrasive groups, with Tukey’s post hoc test showing that glycine had significantly lower roughness than sodium bicarbonate, and erythritol had higher roughness than glycine but was lower than sodium bicarbonate. Conclusions: This study demonstrated that the choice of air-polishing powder and application time significantly affected the surface roughness of both 3M Filtek™ Supreme XTE composite resin and Fuji™ IX glass ionomer cement. Glycine consistently produced the smoothest surfaces, making it a preferable option for clinical scenarios where minimal surface roughness is desired. Sodium bicarbonate, while effective in cleaning, resulted in rougher surfaces, particularly after longer exposure times. These findings suggest that careful selection of polishing powders can enhance the esthetic and functional outcomes of dental restorations, contributing to their longevity. Full article

Carbohydrates have a dietary role, but excessive consumption of high-calorie sugars can contribute to an increased incidence of metabolic diseases and dental caries. Recently, carbohydrates with sweetening properties and low caloric value, such as D-tagatose, have been investigated as alternative sugars. D-tagatose is a rare sugar that has nutritional and functional properties of great interest for health. This literature review presents an approach to the biological effects of D-tagatose, emphasizing its benefits for oral health. Studies report that D-tagatose has antioxidant and prebiotic effects, low digestibility, reduced glycemic and insulinemic responses, and the potential to improve the lipid profile, constituting an alternative for diabetes mellitus and obesity. It can also be observed that D-tagatose has an antioxidant action, favoring the elimination of free radicals and, consequently, causing a reduction in cellular oxidative stress. Furthermore, it also has antibacterial potential against oral species. Regarding oral health, studies have shown that D-tagatose efficiently reversed bacterial coaggregations, including periodontopathogenic species, and impaired the activity and growth of cariogenic bacteria, such as S. mutans. D-tagatose significantly inhibited biofilm formation, pH decrease and insoluble glucan synthesis in S. mutans cultures. Salivary S. mutans counts were also significantly reduced by the consumption of chewing gum containing D-tagatose and xylitol. In addition, there is evidence that tagatose is effective as an air-polishing powder for biofilm decontamination. The literature indicates that D-tagatose can contribute to the prevention of systemic diseases, also constituting a promising agent to improve oral health. Full article

Introduction: Wetting affects chemical and physical properties. In aluminum, superhydrophobic surfaces keep fog, ice, and corrosion at bay. Biomimicry replicates natural processes. The high surface energy of aluminum limits its intrinsic dewetting properties. Existing surface modification methods have disadvantages, such as hazardous chemicals, high costs, and harsh processing conditions. This work is environmentally friendly and overcomes traditional limitations. Methods: Aluminum alloy plates (AA5083) of commercial grade (ASTM-B-209M) were used in the study. Stationary friction stir processing (sFSP) was carried out on a universal milling machine focused solely on surface characteristics using transition metal powders (99% purity). The prepared samples were polished with abrasive papers to 1000 grit after processing. In the microwave hot water treatment (mHWT), processed and unprocessed samples were processed for 10 min at 800 W. A silanization agent was vapor-deposited on the samples following mHWT at 55 °C for 60 min. Results: The low-strain-rate sFSP of aluminum alloys results in substantial grain refinement, reaching ~1 µm for processed samples and ~30 µm for unprocessed samples. Refined grains have a dense and networked nanostructure after mHWT. After silanization, the samples exhibit excellent contact angles (>155°), low tilt angles (10°), and low contact angle hysteresis (5°). The processed samples, featuring highly refined grains, demonstrate low water adhesion (~16 µN) compared to unprocessed samples (~50 μN), attributed to the high interfacial energy of the Cassie state, effectively entrapping air. These processed samples exhibit remarkable de-wetting properties and mechanical resilience, owing to the strong negative capillary pressure (>1100 kPa) generated by highly dense networked nanostructures. Conclusions: In conclusion, the research helps to develop sustainable and durable superhydrophobic aluminum surfaces. The environmentally friendly and cost-effective strategies explored have far-reaching implications for industrial applications, emphasizing opportunities for advancements and practical utilization across various industries. Full article

Complications such as peri-implantitis could ultimately affect the survival of a dental implant. The prevention and treatment of peri-implant diseases require managing bacterial biofilm and controlling environmental risks, including the presence of pro-inflammatory titanium (Ti) particles in the peri-implant niche. Objectives included the evaluation of the size and quantity of Ti particles released from moderately roughened Ti surfaces during common mechanical surface decontamination methods. One hundred and forty moderately roughened Ti discs were divided into seven groups (n = 20 per group); six groups received mechanical decontamination procedures (ultrasonic scaling (US) with a metal tip and poly-ether-ketone (PEEK) under low and medium power settings, air-polishing with erythritol powder, and Ti brush), and the control group underwent air–water spray using a dental triplex. The rinsing solution was collected for Ti mass analysis using inductively coupled plasma mass spectrometry (ICPMS), as well as for Ti particle size and count analysis under scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). US metal tip instrumentation generated 34.00 ± 12.54 μg and 34.44 ± 6.08 μg of Ti under low and medium power settings, respectively. This amount of Ti generation was significantly higher than other instrumentation methods. The mean Ti particle size of the US groups ranged from 0.89 ± 0.27 μm to 1.25 ± 0.24 μm. No statistically significant difference was found in the particle size among US groups and Ti brush group (1.05 ± 0.11 μm), except for US with the PEEK tip, where a significantly smaller mean particle diameter was found at the low power setting (0.89 ± 0.27 μm). Mechanical instrumentation can produce Ti particulates and modify the implant surfaces. US using a metal tip generated the highest amount of Ti with smaller Ti size particles compared to all other commonly used mechanical surface instrumentations. The EDS analysis confirmed Ti in PEEK US tips. It can be suggested that deterioration from the PEEK US tip and Ti brush, as observed under SEM, is an additional source of Ti release during Ti surface decontamination. Full article

Titanium dioxide coatings (TiO₂) were sprayed using a water-stabilized plasma gun (WSP) to form robust self-supporting bodies with the character of a ceramic disc capacitor (CDC). Agglomerated nanometric powder was used as feedstock. Argon was applied for powder feeding as well as coating–cooling to minimize the influence of ambient air. Stainless steel was used as a substrate, and the coatings were released after cooling. A more than three-millimeter-thick self-supporting TiO₂ plate was observed using HR-TEM and SEM. Porosity was studied by image analysis on polished sections. Thermal post-treatment on the coating was conducted at a rather low temperature of 500 °C. The results of the subsequent dielectric measurement showed high permittivity, but this was strongly frequency-dependent and accompanied by a progressively decreasing loss tangent. On the other hand, the plasma-sprayed TiO₂ exhibited persistent DC photoconductivity under and after illumination with a standard bulb. Full article

Effective subgingival biofilm removal is crucial for achieving positive and stable outcomes in periodontal therapy, forming an indispensable part of any periodontal treatment approach. The development of air-polishing tools has emerged as a promising alternative to hand and ultrasonic scalers for dental biofilm removal. The objective of this systematic review was to assess existing literature regarding the subgingival use of various types of air-polishing powders, as an effective method of subgingival biofilm control. For this, 55 articles on this subjected were sourced from searched databases and subjected to an evaluation process of their contained information, which was subsequently structured and compiled into this manuscript. The existing literature acknowledges that good subgingival biofilm control is essential for the success of periodontal therapy, including through subgingival air-polishing, as an adjunctive procedure. This approach has the potential to enhance patient comfort during and after subgingival mechanical plaque removal, thereby mitigating damage to periodontal structures. Consequently, it may lead to improved healing capabilities within the periodontal tissues and the formation of a more stable reparative gingival junctional epithelium. Full article

Air-polishing powders are used to remove stains from the enamel and various restorative materials, but their effect on the discoloration of CAD/CAM blocks remains scarce. Therefore, this study investigated the effect of various air-polishing powders on the color changes in different CAD/CAM blocks to predict the esthetic outcomes. Specimens were prepared from CAD/CAM blocks (Vita Mark II, Paradigm MZ100, Lava Ultimate, Cerasmart, Vita Enamic) and divided into five groups (n = 10) according to the air-polishing powder: sodium bicarbonate; aluminum trihydroxide; calcium carbonate; glycine; and erythritol. Color parameters were measured with a spectrophotometer before and after air-polishing. The color difference was calculated with the ΔE₀₀ formula. Data were statistically evaluated with one-way ANOVA, Tukey, and two-way ANOVA tests (α = 0.05). The CAD/CAM block type and the air-polishing powder type significantly influenced the ΔE₀₀ value, whereas their interactions did not affect it significantly. Calcium carbonate and aluminum trihydroxide significantly increased the ΔE₀₀ values of Lava Ultimate and Cerasmart. Although none of the groups exceeded the acceptability threshold (ΔE₀₀ = 1.8), most exceeded the perceptibility threshold (ΔE₀₀ = 0.8). Consequently, dentists should avoid air-polishing or should repolish with care, depending on restorative material knowledge, to maintain color stability when uncertain about the material encountered clinically. Full article

Aim: To evaluate the effects of two air-polishing powders, during orthodontic treatment, on the surface roughness of sound and demineralised enamel. Materials and methods: Forty-two caries-free human molars were collected, and the enamel surfaces were flattened and polished. Teeth were assigned to two groups (n = 21 each), a sound- and a demineralised-enamel group (subjected to pH-cycling over 2 weeks to create artificially induced white spot-like lesions). Within each group, teeth were further assigned to three groups (n = 7 each), air polished with either sodium bicarbonate, erythritol, or a negative control (water). Each sample was treated for 5 and 150 s. The average surface roughness (Ra) for each sample was measured using white-light-sensor profilometry. Results: On sound enamel, the Ra was roughly 0.17 ± 0.07 μm. After 150 s of air polishing, the Ra increased with erythritol (by 0.28 μm), and even more so with bicarbonate treatment (by 0.68 μm) (p < 0.01). On demineralised enamel, the Ra was roughly 0.79 ± 0.56 μm. The Ra increased after 5 s of air-polishing treatment similarly with erythritol and bicarbonate powders (by 1.03 μm and 1.04 μm, respectively) (p = 0.025), and even more after 150 s (by 2.48 μm and 2.49 μm, respectively) (p < 0.001). Conclusions: On white spot lesions, one should be aware that enamel surface roughness will increase with both erythritol and bicarbonate air-polishing powders, especially with longer exposure times. Full article

Abrasive blasting, sometimes known as sandblasting, is a method used to change the surface condition of materials, clean surfaces, and prepare surfaces for applications such as paint, bonding, coating, etc. The abrasive materials used in abrasive blasting are applied to the surface with compressed air or water and vary according to the purpose of application. The abrasive materials used have negative effects on the environment and human health. So far, organic materials have been used in limited applications in abrasive blasting. However, these materials have a high potential of usage since they are environmentally friendly, safe for human health, and have non-toxic and sustainable properties. In this study, the usability of three different organic wastes (walnut shell, olive pomace and mussel shell) recovered by recycling in abrasive blasting was investigated. In addition, the effect of blasting distance (5, 10 and 15 mm), blasting time (10, 20 and 30 s), powder type (mussel shell, olive pomace and walnut shell) and grain size (38, 45 and 63 µm) on surface roughness have been investigated using the Taguchi L9 experimental design. Regression models were built using ANOVA (Analysis of Variance). Moreover, the surface condition after abrasive blasting was examined using an Al₂O₃ abrasive and compared with other samples. As a result, 5 mm, 30 s, mussel shell and 45 µm test sets were recommended for “larger is better” and it was determined that the blasting time had the greatest effect on the surface roughness by 50.19%. On the other hand, 10 mm, 20 s, walnut shell and 63 µm test sets were recommended for “smaller is better”, and it was determined that blasting time had the greatest effect on the surface roughness by 39.02%. While there was an increase compared to the surface roughness values before abrasive blasting in the first set of experiments, it was determined that the organic material had a polishing rather than an abrasion effect in the second set of experiments. Full article

We aimed to assess the influence of professional dental prophylaxis on the translucency and color stability of a novel simplified shade nanohybrid composite material. Sixty composite disks (5 mm in diameter and 2 mm thick) of light (n = 30) and dark (n = 30) shades were prepared. The specimens were randomly divided into the following three groups (n = 10) according to the prophylaxis procedure used: ultrasonic scaling, air-powder polishing with sodium bicarbonate, and controls. The specimens were submitted to translucency and color analysis based on the CIELab system. Two measurements were performed before and after 48-h storage in coffee. Translucency values of untreated light and dark specimens were 9.15 ± 0.38 and 5.28 ± 1.10, respectively. Air-powder polishing decreased the translucency of the light composite specimens. Storage in coffee resulted in color changes (∆E) ranging between 2.69 and 12.05 and a mean translucency decrease ranging between −0.88 and −6.91. The samples in the light group tended to exhibit greater staining; the treatment method had no effect on ∆E. It can be concluded that light-shade composite restorations are more prone to translucency and color changes resulting from air-powder polishing and contact with staining media. However, further research using other composites and powders is required. Full article

Coix seed is a kind of widespread cereal, and it is used as a folk medicine in China. The present work focuses on the analysis of changes in triacylglycerols (TAGs) content and mycotoxins of coix seed during the processing and storage period for its quality control. Using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS) and high-performance liquid chromatography coupled with evaporative light-scattering detector (HPLC-ELSD) techniques, 42 lipid components in coix seeds were identified, and seven molecular species of TAG in coix seeds from different localities in China were measured and compared, respectively. A correlation analysis between the morphological features and TAGs contents revealed the integrity instead of the particle size of the seed, displaying a highly positive correlation with its quality. The higher contents of TAGs in hulled coix seed than in polished coix seed proposed an alternative processing way. During storage, the changes in TAGs contents of seeds indicated that the storage period should be less than 3 months, and the intact seeds could maintain lipid stability better than the powder. Furthermore, the air humidity and temperature should be controlled during coix seed storage to prevent the production of mycotoxins. These results provide significant insight into the effective control of coix seed quality during processing and storage. Full article

Background: The aim of this study, a prospective case series, was to evaluate the clinical, microbiological, and biochemical impact of the surgical treatment of peri-implantitis. Methods: Thirty subjects with diagnosis of peri-implantitis were treated following a surgical protocol including access flaps, surface decontamination with ultrasonics and glycine powder air-polishing, and systemic antibiotics. Disease resolution was defined by the composite outcome including presence of probing depths (PD) ≤5 mm, absence of bleeding on probing (BoP)/suppuration, and no additional radiographic bone loss (>1 mm). Regression analysis was used to evaluate the patient-, implant-, and prosthetic-related factors possibly influencing treatment outcomes. Results: Patients were evaluated at 6 months post treatment, demonstrating statistically significant reductions in PD (2.14 ± 1.07 mm) and increase in mucosal recession (1.0 ± 0.77 mm). Plaque, BoP, and suppuration were also reduced by 40.56%, 62.22%, and 7.78%, respectively. Disease resolution was achieved in 56.67% of patients. No significant changes were detected in microbiological parameters except for a significant reduction in proportions of Parvimonas micra. Similarly, the levels of the biomarker interleukin-8 in crevicular fluid were significantly lower at 6 months. Conclusions: The proposed surgical treatment of peri-implantitis demonstrated statistically significant clinical improvements although the impact on microbiological and biochemical parameters was scarce. Full article

This umbrella review was conducted to assess the existing literature and scientific evidence on air powder water jet technology (APWJT) in periodontal and peri-implantitis therapy. A systematic literature search for systematic reviews and meta-analyses of the last decade on the use of APWJT in periodontitis and implant patients was performed in the databases of MEDLINE/Ovid, Embase, Cochrane library and Scopus. An additional hand search on PubMed and Google Scholar was conducted. Ten articles that fit the inclusion criteria were selected after the full-text screening. Two systematic reviews, including one with a meta-analysis, investigated the use of APWJT in active periodontal therapy. The use of APWJT as an adjunct to conventional scaling and root planing (SRP) in active periodontal treatment showed improved results in the test group. Six articles, including two with a meta-analysis, reported on the use of APWJT as a stand-alone therapy or as an adjunct in supportive periodontal therapy. Similarly significant improved results were reported for the use of APWJT. Regarding the active treatment of peri-implant mucositis and peri-implantitis, four systematic reviews could not show an improved clinical outcome when APWJT was used as an adjunct to conventional treatment measures. Furthermore, one article investigated APWJT as a stand-alone therapy or as an adjunct in supportive peri-implant mucositis and peri-implantitis therapy. In systematic reviews that also investigated patient perception, APWJT was generally well-tolerated by the patient. Within the limitations of this umbrella review, it can be concluded that the use of APWJT with low-abrasive powders such as glycine, erythritol or trehalose as an adjunct in active periodontitis therapy shows similar clinical results compared to conventional SRP alone. In surgical peri-implantitis treatment, APWJT can be used adjunctively. It could be considered that the use of APWJT in supportive periodontal treatment results in a comparable clinical outcome and an enhanced patient perception, as well as a shorter clinical time. Full article