Experimental investigation on the effect of concentration on the resonance frequency of lipid coated ultrasonically excited microbubbles.

This study presents an experimental investigation of the influence of MB concentration on the resonance frequency of lipid-coated microbubbles (MBs). Expanding on theoretical models and numerical simulations from previous research, this work experimentally investigates the effect of MB size on the rate of resonance frequency increase with concentration, a phenomenon observed across MBs with two different lipid compositions: propylene glycol (PG) and propylene glycol and glycerol (PGG). Employing a custom-designed ultrasound attenuation measurement setup, we measured the frequency-dependent attenuation of MBs, isolating MBs based on size to generate distinct monodisperse sub-populations for analysis.

Numerical investigation of the effect of bubble properties on the linear resonance frequency shift due to inter-bubble interactions in ultrasonically excited lipid coated microbubbles.

Ultrasonically excited microbubbles (MBs) have numerous applications in various fields, such as drug delivery, and imaging. Ultrasonically excited MBs are known to be nonlinear oscillators that generate secondary acoustic emissions in the media when excited by a primary ultrasound wave. The propagation of acoustic waves in the liquid is limited to the speed of sound, resulting in each MB receiving the primary and secondary waves at different times depending on their distance from the ultrasound source and the distance between MBs.

Probing the pressure dependence of sound speed and attenuation in bubbly media: Experimental observations, a theoretical model and numerical calculations.

The problem of attenuation and sound speed of bubbly media has remained partially unsolved. Comprehensive data regarding pressure-dependent changes of the attenuation and sound speed of a bubbly medium are not available. Our theoretical understanding of the problem is limited to linear or semi-linear theoretical models, which are not accurate in the regime of large amplitude bubble oscillations.

The role of primary and secondary delays in the effective resonance frequency of acoustically interacting microbubbles.

Acoustically excited microbubbles (MBs) are known to be nonlinear oscillators with complex dynamics. This has enabled their use in a wide range of applications from medicine to industry and underwater acoustics. To better utilize their potential in applications and possibly invent new ones a comprehensive understanding of their dynamics is required.

A randomized clinical trial comparing the clinical fit and chairside adjustment time for implant-supported crowns fabricated by fully digital and partially digital techniques.

Statement Of Problem: Implant-supported crowns made in both fully and partially digital workflows have been evaluated, but these studies have been mainly performed in vitro. Moreover, data on the comparison of clinical fitting and adjustment time for implant-supported crowns are limited.

Purpose: The purpose of this randomized clinical trial was to evaluate the clinical fit and adjustment time for implant-supported crowns produced by a partially and fully digital workflow in partially edentulous participants.

Effect of on the flexural strength of resin-based restorative materials.

Background: There are a limited number of studies about the effects of microbial aging on the mechanical properties of restorative materials. Therefore, this study aimed to evaluate the effect of simulated aging with on the flexural strength of different resin-based materials.

Materials And Methods: This experimental study was performed on the blocks of different types of restorative materials including composite resin, giomer, and a resin-modified glass ionomer (RMGI).

On the threshold of 1/2 order subharmonic emissions in the oscillations of ultrasonically excited bubbles.

The pressure threshold for 1/2 order subharmonic (SH) emissions and period doubling during the oscillations of ultrasonically excited bubbles is thought to be minimum when the bubble is sonicated with twice its resonance frequency (f). This estimate is based on studies that simplified or neglected the effects of thermal damping. In this work, the nonlinear dynamics of ultrasonically excited bubbles is investigated accounting for the thermal dissipation.

Nonlinear dynamics and bifurcation structure of ultrasonically excited lipid coated microbubbles.

In many applications, microbubbles (MBs) are encapsulated by a lipid coating to increase their stability. However, the complex behavior of the lipid coating including buckling and rupture sophisticates the dynamics of the MBs and as a result the dynamics of the lipid coated MBs (LCMBs) are not well understood. Here, we investigate the nonlinear behavior of the LCMBs by analyzing their bifurcation structure as a function of acoustic pressure.

Nonlinear power loss in the oscillations of coated and uncoated bubbles: Role of thermal, radiation and encapsulating shell damping at various excitation pressures.

This study presents the fundamental equations governing the pressure dependent disipation mechanisms in the oscillations of coated bubbles. A simple generalized model (GM) for coated bubbles accounting for the effect of compressibility of the liquid is presented. The GM was then coupled with nonlinear ODEs that account for the thermal effects.

Critical corrections to models of nonlinear power dissipation of ultrasonically excited bubbles.

Current models for calculating nonlinear power dissipation during the oscillations of acoustically excited bubbles generate non-physical values for the radiation damping (D) term for some frequency and pressure regions that include near resonance oscillations. Moreover, the ratio of the dissipated powers significantly deviate from the values that are calculated by the linear model at low amplitude oscillations (acoustic excitation pressure of P=1 kPa and expansion ratio of <≊1.01).

Comparison of Tensile Bond Strength of Soft Liners to an Acrylic Resin Denture Base with Various Curing Methods and Surface Treatments.

Purpose: To compare the bond strengths of three types of permanent silicone and acrylic resin soft liners to the denture-base acrylic resin by employing both synchronous and asynchronous processing methods and different surface treatments.

Materials And Methods: A total of 198 cylindrical samples were fabricated from denture-base acrylic resin and a 3-mm soft liner. Surface treatments of the samples were classified into five groups (n = 33 each): no treatment (control); erbium:yttrium-aluminum-garnet (Er:YAG) laser; grit-blasting with 150-μm particles; monomer application; and phosphoric acid application.

Collective nonlinear behavior of interacting polydisperse microbubble clusters.

Acoustically excited microbubbles (MBs) have shown to exhibit rich dynamics, enabling them to be employed in various applications ranging from chemistry to medicine. Exploiting the full potential of MBs for applications requires a good understanding of their complex dynamics. Improved understanding of MB oscillations can lead to further enhancement in optimizing their efficacy in many applications and also invent new ones.

A simple method to analyze the super-harmonic and ultra-harmonic behavior of the acoustically excited bubble oscillator.

The bubble oscillator is a highly nonlinear system, which makes it difficult to generate a comprehensive understanding of its oscillatory behavior. One method used to investigate such complex dynamical systems is the bifurcation analysis. Numerous investigations have employed the method of bifurcation diagrams to study the effect of different control parameters on the bubble behavior.

Post-insertion Posterior Single-implant Occlusion Changes at Different Intervals: A T-Scan Computerized Occlusal Analysis.

Aim: The aim of this prospective cohort study was to evaluate the postinsertion posterior single-implant occlusion changes at 3- and 6-month intervals using T-Scan computerized occlusal analysis.

Materials And Methods: A total of 21 patients received single implant, opposed by natural dentition, in posterior regions of the maxilla or mandible (13 premolar, 8 molar) and were finally restored with cemented-retained metal-ceramic crowns. The occlusal contacts were equilibrated according to the implant-protective occlusion concept to develop light contact with heavy occlusion and no contact with light occlusion in maximum inter-cuspation.

Effect of technique and impression material on the vertical misfit of a screw-retained, three-unit implant bridge: An study.

Introduction: A dental impression is a negative imprint of an oral structure that can be used to produce a positive cast of a patient's teeth as a permanent record. The accuracy of the impression affects the accuracy of the cast, and a precise impression is needed in order to create prosthesis with optimal fitting. Minimization of misfit is an important aim in prosthesis science and dental implants.

Three-dimensional accuracy of different impression techniques for dental implants.

Background: Accurate impression making is an essential prerequisite for achieving a passive fit between the implant and the superstructure. The aim of this in vitro study was to compare the three-dimensional accuracy of open-tray and three closed-tray impression techniques.

Materials And Methods: Three acrylic resin mandibular master models with four parallel implants were used: Biohorizons (BIO), Straumann tissue-level (STL), and Straumann bone-level (SBL).

Effect of denture cleansers on color stability and surface roughness of denture base acrylic resin.

Background: Color stability of acrylic resin is one of the most important feature for denture wearers. Many patients use detergent solutions to remove denture stains. The purpose of this study was to evaluate color stability and surface roughness of two common acrylic resins in different detergent and tea solutions.

The microbiology of the peri-implant sulcus following successful implantation of oral prosthetic treatments.

Background: Oral implants are widely used in partially and fully edentulous patients; however, the integration of an implant can be endangered by factors such as intraoral bacteria or inflammatory reactions. The purpose of this study was to evaluate the microbial flora present in the sulcus around dental implants and to assess the relationship between gingival health and microbial flora present.

Materials And Methods: Twenty patients who had received oral implants with no complications were followed for a period of 9 months.