Response surface optimization of sludge dewatering process: synergistic enhancement by ultrasonic, chitosan and sludge-based biochar.

Due to the colloidal stability, the high compressibility and the high hydration of extracellular polymeric substances (EPS), it is difficult to efficiently dehydrate sludge. In order to enhance sludge dewatering, the process of ultrasonic (US) cracking, chitosan (CTS) re-flocculation and sludge-based biochar (SBB) skeleton adsorption of water-holding substances to regulate sludge dewaterability was proposed. Based on the response surface method, the prediction model of the specific resistance to filtration (SRF) and sludge cake moisture content (MC) was established. The US cracking time and the dosage of CTS and SBB were optimized. The results showed that the optimal parameters of the three were 5.08 s, 10.1 mg/g dry solids (DS) and 0.477 g/g DS, respectively. Meantime, the SRF and MC were 5.4125 × 1011 m/kg and 76.8123%, which significantly improved the sludge dewaterability. According to the variance analysis, it is found that the fitting degree of SRF and MC model is good, which also confirms that there is significant interaction and synergy between US, CTS and SBB, and the contribution of CTS and SBB is greater. Moreover, the process significantly improves the sludge's calorific value and makes its combustion more durable.

Experimental investigation of ultrasonic assisted coating on three-point bending behavior of 3D printed polymeric bone plates for biomedical applications.

3D printed Poly Lactic Acid (PLA) bone plates exhibit limited three-point bending strength, restricting their viability in biomedical applications. The application of polydopamine (PDM) enhances the three-point bending strength by undergoing covalent interactions with PLA molecular structure. However, the heavy nature of PDM particles leads to settling at the container base at higher coating solution concentrations. This study investigates the impact of ultrasonic-assisted coating parameters on the three-point bending strength. Utilizing Response Surface Methodology (RSM) for statistical modeling, the study examines the influence of ultrasonic vibration power (UP), coating solution concentration (CC), and submersion time (TIME). RSM optimization recommended 100 % UP, 6 mg/ml CC, and 150 min TIME, resulting in maximum three-point bending strength of 83.295 MPa. Microscopic images from the comparative analysis revealed non-uniform coating deposition with mean thickness of 6.153 µm under normal coating. In contrast, ultrasonic-assisted coating promoted uniform deposition with mean thickness of 18.05 µm. The results demonstrate that ultrasonic-assisted coating induces PDM particle collision, preventing settling at the container base, and enhances three-point bending strength by 7.27 % to 23.24 % compared to the normal coating condition. This study emphasizes on the potential of ultrasonic-assisted coating to overcome the limitations of direct immersion coating technique.

Cavitron ultrasonic surgical aspirator (CUSA) compared with conventional pancreatic transection in distal pancreatectomy: study protocol for the randomised controlled CUSA-1 pilot trial.

BACKGROUND: Postoperative pancreatic fistula (POPF) remains the most common and serious complication after distal pancreatectomy. Many attempts at lowering fistula rates have led to unrewarding insignificant results as still up to 30% of the patients suffer from clinically relevant POPF. Therefore, the development of new innovative methods and procedures is still a cornerstone of current surgical research.The cavitron ultrasonic surgical aspirator (CUSA) device is a well-known ultrasound-based parenchyma transection method, often used in liver and neurosurgery which has not yet been thoroughly investigated in pancreatic surgery, but the first results seem very promising. METHODS: The CUSA-1 trial is a randomised controlled pilot trial with two parallel study groups. This single-centre trial is assessor and patient blinded. A total of 60 patients with an indication for open distal pancreatectomy will be intraoperatively randomised after informed consent. The patients will be randomly assigned to either the control group with conventional pancreas transection (scalpel or stapler) or the experimental group, with transection using the CUSA device. The primary safety endpoint of this trial will be postoperative complications ≥grade 3 according to the Clavien-Dindo classification. The primary endpoint to investigate the effect will be the rate of POPF within 30 days postoperatively according to the ISGPS definition. Further perioperative outcomes, including postpancreatectomy haemorrhage, length of hospital stay and mortality will be analysed as secondary endpoints. DISCUSSION: Based on the available literature, CUSA may have a beneficial effect on POPF occurrence after distal pancreatectomy. The rationale of the CUSA-1 pilot trial is to investigate the safety and feasibility of the CUSA device in elective open distal pancreatectomy compared with conventional dissection methods and gather the first data on the effect on POPF occurrence. This data will lay the groundwork for a future confirmatory multicentre randomised controlled trial. ETHICS AND DISSEMINATION: The CUSA-1 trial protocol was approved by the ethics committee of the University of Heidelberg (No. S-098/2022). Results will be published in an international peer-reviewed journal and summaries will be provided in lay language to study participants and their relatives. TRIAL REGISTRATION NUMBER: DRKS00027474.

Concern about the risk of aerosol contamination from ultrasonic scaler: a systematic review and meta-analysis.

BACKGROUND: Many instruments used in dentistry are rotary, such as handpieces, water syringes, and ultrasonic scalers that produce aerosols. The spray created by these instruments can carry, in addition to water, droplets of saliva, blood, and microorganisms, which can pose a risk of infections for healthcare professionals and patients. Due to the COVID-19 pandemic, this gained attention. OBJECTIVE: The aim was to carry out a systematic review of the evidence of the scope of the aerosol produced by ultrasonic scaler in environmental contamination and the influence of the use of intraoral suction reduction devices. DESIGN: Scientific literature was searched until June 19, 2021 in 6 databases: Pubmed, EMBASE, Web of science, Scopus, Virtual Health Library and Cochrane Library, without restrictions on language or publication date. Studies that evaluated the range of the aerosol produced by ultrasonic scaler during scaling/prophylaxis and the control of environmental contamination generated by it with the use of low (LVE) and high (HVE) volume evacuation systems were included. RESULTS: Of the 1893 potentially relevant articles, 5 of which were randomized controlled trials (RCTs). The meta-analysis of 3 RCTs showed that, even at different distances from the patient's oral cavity, there was a significant increase in airborne bacteria in the dental environment with the use of ultrasonic scaler. In contrast, when meta-analysis compared the use of HVE with LVE, there was no significant difference (P = 0.40/CI -0.71[-2.37, 0.95]) for aerosol produced in the environment. CONCLUSIONS: There is an increase in the concentration of bioaerosol in the dental environment during the use of ultrasonic scaler in scaling/prophylaxis, reaching up to 2 m away from the patient's mouth and the use of LVE, HVE or a combination of different devices, can be effective in reducing air contamination in the dental environment, with no important difference between different types of suction devices.

Using ultrasonic-assisted sodium bicarbonate treatment to improve the gel and rheological properties of reduced-salt pork myofibrillar protein.

To study the impact of ultrasonic duration (0, 30, and 60 min) and sodium bicarbonate concentration (0% and 0.2%) on the gel properties of reduced-salt pork myofibrillar protein, the changes in cooking yield, colour, water retention, texture properties, and dynamic rheology were investigated. The findings revealed that added sodium bicarbonate significantly increased (P < 0.05) cooking yield, hardness, springiness, and strength of myofibrillar protein while reducing centrifugal loss. Furthermore, the incorporation of sodium bicarbonate led to a significant decrease in L⁎, a⁎, b⁎, and white values of cooked myofibrillar protein; these effects were further amplified with increasing ultrasonic duration (P < 0.05). Additionally, storage modulus (G') significantly increased for myofibrillar protein treated with ultrasonic-assisted sodium bicarbonate treatment resulting in a more compact gel structure post-cooking. In summary, the results demonstrated that ultrasonic-assisted sodium bicarbonate treatment could enhance the tightness of reduced-salt myofibrillar protein gel structure while improving the water retention and texture properties.

Endoscopic resection of third ventricle colloid cysts using an ultrasonic aspirator.

An important step in the performance of endoscopic resection of colloid cysts of the third ventricle is the forced aspiration of cyst contents. The different consistencies these cysts may have can limit their complete resection and increase the likelihood of complications. The introduction of the ultrasonic neuroendoscopic aspirator allows cysts to be emptied more easily than with a conventional rigid aspirator, improving the feasibility of resection even in more solid cysts. The ability to regulate ultrasound and aspiration increases safety in a reduced and highly morbid space such as the third ventricle. Our objective was to determine the safety and efficiency of the ultrasonic aspirator for endoscopic resection of colloid cysts of the third ventricle. This was a retrospective descriptive study of patients with colloid cysts of the third ventricle undergoing neuroendoscopic resection using an ultrasonic aspirator between 2016-2023. Clinical, radiological, and procedural variables were studied. Mean, median and range were analyzed for quantitative variables and percentages and frequencies for qualitative variables. We present a series of 11 patients with colloid cysts of the third ventricle. The mean age was 44 years (27-69). All had biventricular hydrocephalus, with a mean cyst diameter of 15 mm (9-20). The lateral ventricle was accessed using the transforaminal approach in seven patients and the transchoroidal approach in three patients. All patients underwent septostomy. The mean endoscopy time was 40 min (29-68). Complete resection was possible in 10 patients. Median follow-up was 16 months (1-65) with 100% clinical improvement. At the end of follow-up, no patient had recurrence of the lesion. Based on our experience, the ultrasonic aspirator can be used safely and effectively for the resection of colloid cysts of the third ventricle, achieving high rates of complete resection with minimal postoperative complications.

Comparison of Doppler ultrasonic sphygmomanometry, oscillometry and high-definition oscillometry for non-invasive blood pressure measurement in conscious cats.

OBJECTIVES: Systemic arterial hypertension is a common occurrence and can have serious adverse consequences in cats. Therefore, measuring blood pressure is very important. There are many indirect blood pressure measurement devices available. This study compared Doppler, oscillometric (petMAP Graphic II, SunTech Vet20, the Cardell Insight-X0000) and high-definition oscillometry devices for the non-invasive measurement of blood pressure in conscious cats. METHODS: In this prospective study, blood pressure was measured in 32 cats using the different devices according to the recommendations of the American College of Veterinary Internal Medicine Consensus Statement. Blood pressures (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP]), time to complete measurements, number of attempts needed, coefficient of variation (CV) between the blood pressure measurements of the different devices, ease of completing measurements and apparent stress level of the cat were assessed. RESULTS: There was a significant difference between devices in the time taken to obtain blood pressure readings and the number of attempts necessary to obtain six reliable measurements. The CV of the Doppler device was significantly smaller than that of the rest of the devices, but there were no other differences between the devices. The mean SBP, DBP and MAP measured by the petMAP device were significantly higher than the measurements from the other devices. The perceived ease of measurement was not significantly different between the various machines. The perceived level of stress of measurement with the Doppler device was significantly higher compared with the other devices but did not lead to an increased SBP. CONCLUSIONS AND RELEVANCE: Using a Doppler device to measure blood pressure in conscious cats is fast, relatively easy and gives reliable results. A disadvantage is that the Doppler device can only measure SBP, while oscillometric devices also provide DBP and MAP. However, in veterinary medicine, systolic hypertension is considered the most relevant.

Surface Modification of Ultrasonic Cavitation by Surfactants Improves Detection Sensitivity of α-Synuclein Amyloid Seeds.

The rapid amplification and sensitive detection of α-synuclein (αSyn) seeds is an efficient approach for the early diagnosis of Parkinson's disease. Ultrasonication stands out as a promising method for the rapid amplification of αSyn seeds because of its robust fibril fragmentation capability. However, ultrasonication also induces the primary nucleation of αSyn monomers, deteriorating the seed detection sensitivity by generating seed-independent fibrils. In this study, we show that an addition of surfactants to the αSyn monomer solution during αSyn seed detection under ultrasonication remarkably improves the detection sensitivity of the αSyn seeds by a factor of 100-1000. Chemical kinetic analysis reveals that these surfactants reduce the rate of primary nucleation while promoting the fragmentation of the αSyn fibrils under ultrasonication. These effects are attributed to the modification of the ultrasonic cavitation surface by the surfactants. Our study enhances the utility of ultrasonication in clinical assays targeting αSyn seeds as the Parkinson's disease biomarker.

Echo detection thresholds in big brown bats (Eptesicus fuscus) vary with echo spectral content.

Echolocating big brown bats (Eptesicus fuscus) broadcast downward frequency-modulated sweeps covering the ultrasonic range from 100-23 kHz in two harmonics. They perceive target range from the time delay between each broadcast and its returning echo. Previous experiments indicated that the bat's discrimination acuity for broadcast-echo delay declines when the lowest frequencies (23-35 kHz) in the first harmonic of an echo are removed. This experiment examined whether echo detection is similarly impaired. Results show that detection thresholds for echoes missing these lowest frequencies are raised. Increased thresholds for echoes differing in spectra facilitates the bat's ability to discriminate against clutter.

Characterization of the collagen network of human cheek skin using ultrasonic microscopy.

Dermal collagen is the most abundant component of human skin and has a network structure that regulates the mechanical properties of the skin. Therefore, non-invasive characterization of the collagen network would be beneficial for the evaluation of skin conditions. The microscopic substructures of the network, which are individual bundles and fibers, have been optically investigated. However, the macroscopic structure of the collagen network has not been assessed. To evaluate the dermal collagen network, we developed two new indicators, volume filling factor (VFF) and collagen fiber texture (CFT), to analyze three-dimensional echo intensity maps of high-frequency ultrasonic microscopy. By identifying the difference in the elastic modulus components of the dermal layer of facial skin, the density and texture of the collagen network were characterized using VFF and CFT, respectively. These new indicators revealed that the density decreased and the texture became fine with facial age. This study demonstrates that ultrasonic microscopy is useful for investigating skin conditions, paving the way for diagnostic applications in dermatology and aesthetic medicine.

The Mouse Inferior Colliculus Responds Preferentially to Non-Ultrasonic Vocalizations.

The inferior colliculus (IC), the midbrain auditory integration center, analyzes information about social vocalizations and provides substrates for higher level processing of vocal signals. We used multichannel recordings to characterize and localize responses to social vocalizations and synthetic stimuli within the IC of female and male mice, both urethane anesthetized and unanesthetized. We compared responses to ultrasonic vocalizations (USVs) with other vocalizations in the mouse repertoire and related vocal responses to frequency tuning, IC subdivisions, and sex. Responses to lower frequency, broadband social vocalizations were widespread in IC, well represented throughout the tonotopic axis, across subdivisions, and in both sexes. Responses to USVs were much more limited. Although we observed some differences in tonal and vocal responses by sex and subdivision, representations of vocal responses by sex and subdivision were largely the same. For most units, responses to vocal signals occurred only when frequency response areas overlapped with spectra of the vocal signals. Since tuning to frequencies contained within the highest frequency USVs is limited (<15% of IC units), responses to these vocalizations are correspondingly limited (<5% of sound-responsive units). These results highlight a paradox of USV processing in some rodents: although USVs are the most abundant social vocalization, their representation and the representation of corresponding frequencies are less than lower frequency social vocalizations. We interpret this paradox in light of observations suggesting that USVs with lower frequency elements (<50 kHz) are associated with increased emotional intensity and engage a larger population of neurons in the mouse auditory system.

Machine learning modeling for ultrasonic quality attribute assessment of pharmaceutical tablets for continuous manufacturing and real-time release testing.

In in-process quality monitoring for Continuous Manufacturing (CM) and Critical Quality Attributes (CQA) assessment for Real-time Release (RTR) testing, ultrasonic characterization is a critical technology for its direct, non-invasive, rapid, and cost-effective nature. In quality evaluation with ultrasound, relating a pharmaceutical tablet's ultrasonic response to its defect state and quality parameters is essential. However, ultrasonic CQA characterization requires a robust mathematical model, which cannot be obtained with traditional first principles-based modeling approaches. Machine Learning (ML) using experimental data is emerging as a critical analytical tool for overcoming such modeling challenges. In this work, a novel Deep Neural Network-based ML-driven Non-Destructive Evaluation (ML-NDE) modeling framework is developed, and its effectiveness for extracting and predicting three CQAs, namely defect states, compression force levels, and amounts of disintegrant, is demonstrated. Using a robotic tablet handling experimental rig, each attribute's distinct waveform dataset was acquired and utilized for training, validating, and testing the respective ML models. This study details an advanced algorithmic quality assessment framework for pharmaceutical CM in which automated RTR testing is expected to be critical in developing cost-effective in-process real-time monitoring systems. The presented ML-NDE approach has demonstrated its effectiveness through evaluations with separate (unused) test datasets.

Multiple ultrasonic parametric imaging for the detection and monitoring of high-intensity focused ultrasound ablation.

Numerous quantitative ultrasound imaging techniques have demonstrated superior monitoring performance for thermal ablation when compared to conventional ultrasonic B-mode imaging. However, the absence of comparative studies involving various quantitative ultrasound imaging techniques hinders further clinical exploration. In this study, we simultaneously reconstructed ultrasonic Nakagami imaging, ultrasonic horizontally normalized Shannon entropy (hNSE) imaging, and ultrasonic differential attenuation coefficient intercept (DACI) imaging from ultrasound backscattered envelope data collected during high-intensity focused ultrasound ablation treatment. We comprehensively investigated their performance differences through qualitative and quantitative analyses, including the calculation of contrast-to-noise ratios (CNR) for ultrasonic images, receiver operating characteristic (ROC) analysis with corresponding indicators, the analysis of lesion area fitting relationships, and computational time consumption comparison. The mean CNR of hNSE imaging was 10.98 ± 4.48 dB, significantly surpassing the 3.82 ± 1.40 dB (p < 0.001, statistically significant) of Nakagami imaging and the 2.45 ± 0.74 dB (p < 0.001, statistically significant) of DACI imaging. This substantial difference underscores that hNSE imaging offers the highest contrast resolution for lesion recognition. Furthermore, we evaluated the ability of multiple ultrasonic parametric imaging to detect thermal ablation lesions using ROC curves. The area under the curve (AUC) for hNSE was 0.874, exceeding the values of 0.848 for Nakagami imaging and 0.832 for DACI imaging. Additionally, hNSE imaging exhibited the strongest linear correlation coefficient (R = 0.92) in the comparison of lesion area fitting, outperforming Nakagami imaging (R = 0.87) and DACI imaging (R = 0.85). hNSE imaging also performs best in real-time monitoring with each frame taking 6.38 s among multiple ultrasonic parametric imaging. Our findings unequivocally demonstrate that hNSE imaging excels in monitoring HIFU ablation treatment and holds the greatest potential for further clinical exploration.

Degradation of Procion brilliant yellow H-E6G using ultrasonic and hydrodynamic cavitation combined with oxidants with demonstration at pilot scale.

The current study focuses on the degradation of Procion brilliant yellow H-E6G, an azo dye, using ultrasonic and hydrodynamic cavitation (HC), evaluating the impact of various parameters on the extent of degradation. The use of only ultrasound showed less oxidation capacity as indicated by only 19.1% degradation at an optimized power of 140 W, pH of 2.5, temperature of 40°C, and initial dye concentration of 15 ppm. The effectiveness of hybrid approaches involving US + H2 O2 , US + Fenton, and US + H2 O2 + potassium persulfate (KPS) was subsequently evaluated under optimized conditions. A notable enhancement in decolorization extent was observed for combined operations, including US + H2 O2 , US + Fenton, and US + H2 O2 + KPS (dual oxidant scheme) with the actual decolorization extents as 80.6%, 85%, and 92.2% respectively. An optimized scheme of US + H2 O2 + KPS was also utilized to decolorize the dye at a pilot scale using a US flow cell and also an HC reactor that yielded 91.8% and 88% reductions in initial concentration. The dye decolorization was elucidated to follow first-order kinetics for all the individual and combination approaches. The obtained values of the rate constants were also utilized for the evaluation of the synergistic index. A toxicity analysis was also performed on the dye, both before and following treatment, utilizing two bacterial strains. A comparative analysis of various treatment approaches has been presented focusing on factors such as cavitational yield, operational expenses, and energy requirements. The study elucidated that the combination of US + H2 O2 + KPS effectively removes Procion brilliant yellow H-E6G giving 92.2% as the maximum degradation at an operating cost of 0.1862 $/L. PRACTITIONER POINTS: First depiction of cavitative degradation of Procion brilliant yellow H-E6G Optimizing the equipment operating parameters and chemical oxidants Demonstration of optimized treatment scheme at pilot scale Evaluation of various approaches based on synergy and costs of treatment US + H2 O2  + KPS is the best approach for dye degradation.

Effects of a new magnetostrictive ultrasonic scaler and a traditional piezoelectric ultrasonic scaler on root surfaces and patient complaints.

Tooth wear and pain are the primary concerns of patients undergoing periodontal scaling. The aims of this study were to compare the effects of a new magnetostrictive ultrasonic scaler and a traditional piezoelectric ultrasonic scaler on tooth surface roughness and calculus removal and to determine their impacts on patient discomfort during supragingival cleaning. This article had two parts: an in vitro study and a clinical study. In the in vitro study, thirty teeth with subgingival calculus were randomly assigned to two scaling treatment groups: magnetostrictive scalers (n = 15) and piezoelectric scalers (n = 15). Surface roughness measurements were taken at baseline and after scaling, and the root samples were visualised by SEM after scaling. Additionally, a single-centre randomised split-mouth clinical trial was conducted. Eighty-five participants diagnosed with chronic gingivitis or periodontitis were randomly assigned to receive supragingival scaling. The magnetostrictive scaler was used in half of the mouths (n = 85), and the piezoelectric scaler was used in the other half of the mouths (n = 85). Data on pain, noise, and vibration were collected using a VAS questionnaire, and the operating time was recorded. In both in vitro and clinical studies, magnetostrictive scalers were reported to be more effective than piezoelectric scalers in removing dental deposits (P < 0.05). Additionally, the root surface after scaling with the magnetostrictive scaler was smoother than that after scaling with the piezoelectric scaler in the in vitro study (P = 0.02). SEM examination also revealed that fewer dental materials were lost after instrumentation with the magnetostrictive scaler than after instrumentation with the piezoelectric scaler. Piezoelectric scalers caused less discomfort to patients in terms of pain, noise, and vibration than magnetostrictive scalers (P < 0.05). According to this clinical study, the magnetostrictive scaler caused more discomfort during supragingival scaling than the piezoelectric scaler. Moreover, the magnetostrictive scaler was also more efficient and produced a smoother root surface with less material loss after scaling than the piezoelectric scaler, as demonstrated in the in vitro study.

Postendodontic Pain Using Single File System with Different Irrigation Protocols in Single-visit Root Canal Treatment: A Randomized Control Trial.

AIM: To evaluate the intensity of postendodontic pain (PEP) using final irrigation with side-vented needle (SV), EndoActivator (EA), and Ultra X (UX) in single-visit endodontics (SVE) with F-One rotary files. MATERIALS AND METHODS: A total 150 patients indicated for endodontic treatment were selected. Single-visit endodontics treatment was performed under local anesthesia. For the final irrigation protocol, they were divided into three groups: group I (SV), group II (EA), and group III (UX). The severity of PEP was assessed using visual analogue scale (VAS) score after 6, 12, 24, and 48 hours. Analgesics taken by patients, for pain, were also recorded. Finally, the data were tabulated and statistically analyzed using SPSS 20.0 software at a level of significance being 0.05. RESULTS: Postendodontic pain was less in group III (UX) and group II (EA) compared with group I (SV) at 6 and 12 hours, which is statistically significant (p < 0.05). There was no statistically significant difference found after 24 hours and 48 hours. CONCLUSION: The intensity of PEP was minimum in patients treated with EndoActivator and ultrasonic along with single rotary file systems. The incidence of analgesic intake was similar in all three groups. How to cite this article: Kathiria NV, Attur K, Bagda KM, et al. Postendodontic Pain Using Single File System with Different Irrigation Protocols in Single-visit Root Canal Treatment: A Randomized Control Trial. J Contemp Dent Pract 2024;25(2):180-185.

Effect of ultrasonic and sonic instrumentation on shear bond strength of resin composite to enamel: An in vitro study.

PURPOSE: To assess and compare the effects of sonic and ultrasonic instrumentation on shear bond strength (SBS) and investigate the influence of adhesive system application modes (etch&rinse/self-etch) on SBS. METHODS: In this experimental study, 45 extracted sound human molars were selected. Mesial and distal surfaces of the teeth were abraded until 90 smooth enamel surfaces were obtained. Specimens were divided into two groups, with half (N= 45) conditioned in etch&rinse mode and the remaining (N= 45) in self-etch mode using Tetric N Bond Universal. Composite resin discs were produced on these surfaces by filling Teflon molds. All specimens were aged via thermocycling. Each group was further divided into three more groups (n= 15) according to the type of periodontal instrumentation (ultrasonic, sonic or none). SBS values were recorded and analyzed using two-way ANOVA. Fracture sites were examined under a stereomicroscope. RESULTS: The type of periodontal instrumentation had no significant effect on SBS values, whether sonic, ultrasonic or their absence (P= 0.945). The type of adhesive system mode had a significant influence on the shear bond strength values. Etch&rinse groups had significantly higher shear bond strength values than self-etch groups (P< 0.001). CLINICAL SIGNIFICANCE: This study reassures practitioners that sonic and ultrasonic instruments are safe for enamel bonding and highlights the importance of selecting adhesive techniques for optimal restorative outcomes.

Bioresorbable shape-adaptive structures for ultrasonic monitoring of deep-tissue homeostasis.

Monitoring homeostasis is an essential aspect of obtaining pathophysiological insights for treating patients. Accurate, timely assessments of homeostatic dysregulation in deep tissues typically require expensive imaging techniques or invasive biopsies. We introduce a bioresorbable shape-adaptive materials structure that enables real-time monitoring of deep-tissue homeostasis using conventional ultrasound instruments. Collections of small bioresorbable metal disks distributed within thin, pH-responsive hydrogels, deployed by surgical implantation or syringe injection, allow ultrasound-based measurements of spatiotemporal changes in pH for early assessments of anastomotic leaks after gastrointestinal surgeries, and their bioresorption after a recovery period eliminates the need for surgical extraction. Demonstrations in small and large animal models illustrate capabilities in monitoring leakage from the small intestine, the stomach, and the pancreas.

Monitoring homeostasis with ultrasound.

An implant could allow at-home monitoring of deep-tissue changes after surgery.

Ultrasonic irrigation flows in root canals: effects of ultrasound power and file insertion depth.

Ultrasonic irrigation during root canal treatment can enhance biofilm disruption. The challenge is to improve the fluid flow so that the irrigant reaches areas inaccessible to hand instrumentation. The aim of this study is to experimentally investigate how the flow field and hydrodynamic forces induced by ultrasonic irrigation are influenced by the ultrasound power and file insertion depth. A root canal phantom was 3D printed and used as a mold for the fabrication of a PDMS channel. An ultrasonic instrument with a #15K-file provided the irrigation. The flow field was studied by means of Particle Image Velocimetry (PIV). The time averaged velocity and shear stress distributions were found to vary significantly with ultrasound power. Their maximum values increase sharply for low powers and up to a critical power level. At and above this setting, the flow pattern changes, from the high velocity and shear stress region confined in the vicinity of the tip, to one covering the whole root canal domain. Exceeding this threshold also induces a moderate increase in the maximum velocities and shear stresses. The insertion depth was found to have a smaller effect on the measured velocity and shear stresses. Due to the oscillating nature of the flow, instantaneous maximum velocities and shear stresses can reach much higher values than the mean, especially for high powers. Ultrasonic irrigation will benefit from using a higher power setting as this does produce greater shear stresses near the walls of the root canal leading to the potential for increased biofilm removal.