Ultrasonic assessment of fresh cheese composition

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Does the Ultrasonic Cleaning Medium Affect the Adhesion of Resin Cement to Feldspathic Ceramic?

Purpose: To evaluate the effect of different cleaning media on the adhesion of resin cement to feldspathic ceramic after etching.Materials and Methods: The cementation surfaces of ceramic blocks (N = 20, n = 5 per group) were etched with 10% hydrofluoric acid (HF) gel for 20 s and rinsed for 60 s. They were then randomly assigned to 4 groups: G1: air-water spray+drying (control); G2: ultrasonic cleaning in distilled water for 4 min+drying; G3: ultrasonic cleaning in 99.5% acetone for 4 min+drying; G4: ultrasonic cleaning in 70% alcohol for 4 min+drying. The ceramic blocks were silanized and cemented (RelyX ARC) to the composite blocks. Subsequently, the microtensile bond strength test (mu TBS) was performed. In addition, EDS analysis was made to assess the elemental composition of the conditioned and cleaned ceramic surfaces.Results: A significantly higher mean mu TBS was obtained when specimens had been ultrasonically cleaned in distilled water (G2: 18.8 +/- 0.4 MPa) (p < 0.05) compared to other groups (G1: 16.6 +/- 0.5; G3: 16.1 +/- 0.9; G4: 15.8 +/- 1.4) (one-way ANOVA). EDS analysis indicated the presence of F- only in G1. Dissolved precipitates after HF etching were removed by ultrasonic cleaning.Conclusion: Cleaning the HF-etched ceramic surface ultrasonically in distilled water is recommended, instead of rinsing it with air-water spray only.

Ultrasonic versus high-speed cavity preparation: Analysis of increases in pulpal temperature and time to complete preparation

Statement of problem. The use of ultrasonic tips has become an alternative for cavity preparation. However, there are concerns about this type of device, particularly with respect to intrapulpal temperatures and cavity preparation time.Purpose. The purpose of this study was to analyze pulpal temperature increases generated by an ultrasonic cavity preparation with chemical vapor deposition (CVD) tips, in comparison to preparation with a high-speed handpiece with a diamond rotary cutting instrument. The time required to complete the cavity preparation with each system was also evaluated.Material and methods. Thermocouples were positioned in the pulp chamber of 20 extracted human third molars. Slot-type cavities (3 x 3 x 2 mm) were prepared on the buccal and the lingual surfaces of each tooth. The test groups were: high-speed cavity preparation with diamond rotary cutting instruments (n = 20) and ultrasonic cavity preparation with CVD points (n = 20). During cavity preparation, the increases In pulpal temperature, and the time required for the preparation, were recorded and analyzed by Student's t test for paired samples (alpha = .05).Results. The average pulpal temperature increases were 4.3 degrees C for the high-speed preparation and 3.8 degrees C for the ultrasonic preparation, which were statistically similar (P = .052). However, significant differences were found (P < .001) for the time expended (3.3 minutes for the high-speed bur and 13.77 minutes for the ultrasound device).Conclusions. The intrapulpal temperatures produced during cavity preparation by ultrasonic tips versus high-speed bur preparation were similar. However, the use of the ultrasonic device required 4 times longer for the completion of a cavity preparation.

Determination of Zinc in Lubricating Oil by Flame MS Employing Ultrasonic Extraction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Preparation and characterization of LiNi0.8Co0.2O2/PANI microcomposite electrode materials under assisted ultrasonic irradiation

A preparation method for a new electrode material based on the LiNi0.8Co0.2O2/polyaniline (PANI) composite is reported. This material is prepared by in situ polymerization of aniline in the presence of LiNi0.8Co0.2O2 assisted by ultrasonic irradiation. The materials are characterized by XRD, TG-DTA, FTIR, XPS, SEM-EDX, AFM, nitrogen adsorption (BET surface area) and electrical conductivity measurements. PANI in the emeraldine salt form interacts with metal-oxide particles to assure good connectivity. The dc electrical conductivity measurements at room temperature indicate that conductivity values are one order of magnitude higher in the composite than in the oxide alone. This behavior determines better reversibility for Li-insertion in charge-discharge cycles compared to the pristine mixed oxide when used as electrode of lithium batteries. (c) 2005 Elsevier B.V. All rights reserved.

Thermal characterization of an ultrasonic density-measurement cell

An ultrasonic density-measurement cell is experimentally characterized as a function of temperature. The measurement of propagation velocity and density of several liquids is performed in the 15 degrees C-40 degrees C temperature range. Results are compared to the tabulated values in the case of distilled water, showing an accuracy of 0.07% for the propagation velocity. The cell was tested with distilled water, alcohol, and homogenized milk, and density values are compared to those obtained with a pycnometer, showing 0.2% accuracy in density measurement for stabilized temperature and 0.4% accuracy under thermal gradient conditions.

The Combination of Amoxicillin and Metronidazole Improves Clinical and Microbiologic Results of One-Stage, Full-Mouth, Ultrasonic Debridement in Aggressive Periodontitis Treatment

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrasonic characterization of emulsions: milk and water in oil

Measurements of ultrasonic attenuation and velocity in milk and low concentration water-in-oil (W/O) emulsion were conducted, using a measurement cell with a double-element transducer that eliminates diffraction losses. The milk is characterized by the attenuation coefficient, while in the case of water-in-oil emulsions, the characterization is best represented by the propagation velocity.

Energy method to calculate the density of liquids using ultrasonic reflection techniques

In this work it is introduced a new approach to calculate the density of liquids in terms of the energies of the acoustic signals. This method is compared to other methods in the time domain (peak-to-peak amplitudes) and frequency domain magnitudes at a single frequency. It is used a measurement cell based on a multiple reflection technique, and it is developed an acoustic model for the cell. Simulations and experiments using several liquids are presented, showing that the energy method a less sensitive to noise than the other techniques. The relative errors in the density are smaller than 0.2% when compared to the values measured with a pycnometer.

Thermodynamic response of an ultrasonic densitometer

An ultrasonic densitometer is experimentally characterized as a function of temperature. The measurement of propagation velocity and density of several liquids is performed in the 15 to 40°C temperature range. Results are compared to tabulated values in the case of distilled water, showing accuracy of 0.07% for the propagation velocity. Density values are compared to those obtained with a pycnometer, showing 0.2% accuracy in density measurement for stabilized temperature and 0.4% under thermal gradient conditions.

Efficacy of ultrasonic, electric and manual toothbrushes in patients with fixed orthodontic appliances

Objective: This crossover study compared the efficacy of an ultrasonic toothbrush for the reduction of plaque, gingival inflammation, and levels of Streptococcus mutans, in relation to an electric and a manual toothbrush. Materials and Methods: Twenty-one patients with orthodontic appliances were divided into three groups. All patients were evaluated by a periodontist and samples of saliva were collected for quantification of S mutans. The patients received their first brushes with appropriate instructions. For each crossover leg, patients used each toothbrush for a period of 30 days. At the end of each washout period, participants received a periodontal evaluation and new samples of saliva were collected. After 15 days of using their own toothbrushes, patients received the next toothbrushes in the experimental sequence. Results: The ultrasonic brush group presented significant improvement in the reduction of visible plaque on the buccal surfaces (-6.36%, P = .007). The counts of S mutans decreased in the electric (2.04 × 105 to 1.36 × 105 colony-forming units [CFU]/mL) and ultrasonic (2.98 × 105 to 1.84 × 105 CFU/mL) groups. There were no statistical differences among the three brushes for the clinical and microbiological parameters evaluated. Conclusions: This study did not demonstrate that the ultrasonic toothbrush was better in reducing gingival inflammation in adolescent orthodontic patients, but plaque scores were lowered on buccal surfaces of teeth with orthodontic brackets. In addition, S mutans counts were markedly decreased in the electric and ultrasonic groups, which should be related to a reduced risk of oral disease. © 2006 by The EH Angle Education and Research Foundation, Inc.

Comparison of manual versus sonic and ultrasonic toothbrushes: a review.

PURPOSE: This review of the literature intends to evaluate the effect of brushes with high frequency motion when compared with manual toothbrushes regarding the indices of plaque and gingival bleeding. METHODS: Patients presenting gingivitis and/or chronic periodontitis were evaluated in addition to patients having osseointegrated implants and fixed orthodontic appliances. Pertinent literature was reviewed to select articles according to previously defined inclusion criteria. RESULTS: In the assessed studies results showed significant decreases in plaque and gingival indices by utilization of both types of brushes. However, in the selected studies where sonic brushes were tested in orthodontic and dental implant patients there was a more significant decrease in the indices. Furthermore, there was no indication of gingival recession attributed to product use. CONCLUSION: Future studies with a more homogeneous methodology and better experiment designs will be needed.

Effect of ultrasonic instrumentation on the bond strength of crowns cemented with zinc phosphate cement to natural teeth. An in vitro study

Several studies have reported the benefits of sonic and/or ultrasonic instrumentation for root debridement, with most of them focusing on changes in periodontal clinical parameters. The present study investigated possible alterations in the tensile bond strength of crowns cemented with zinc phosphate cement to natural teeth after ultrasonic instrumentation. Forty recently extracted intact human third molars were selected, cleaned and stored in physiologic serum at 4°C. They received standard preparations, at a 16° convergence angle, and AgPd alloy crowns. The crowns were cemented with zinc phosphate cement and then divided into four groups of 10 teeth each. Each group was then subdivided into two subgroups, with one of the subgroups being submitted to 5,000 thermal cycles ranging from 55 ± 2 to 5 ± 2°C, while the other was not. Each group was submitted to ultrasonic instrumentation for different periods of time: group 1 - 0 min (control), group 2 - 5 min, group 3 - 10 min, and group 4 - 15 min. Tensile bond strength tests were performed with an Instron testing machine (model 4310). Statistical analysis was performed using ANOVA and Tukey's test at the 5% level of significance. A significant reduction in the tensile bond strength of crowns cemented with zinc phosphate and submitted to thermal cycles was observed at 15 min (196.75 N versus 0 min = 452.01 N, 5 min = 444.23 N and 10 min = 470.85 N). Thermal cycling and ultrasonic instrumentation for 15 min caused a significant reduction in tensile bond strength (p < .05).