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PubMedDate not supplied

Ultrasonic atomization for spray drying: a versatile technique for the preparation of protein loaded biodegradable microspheres.

Bovine serum albumin (BDA) loaded microspheres with a spherical shape and smooth surface structure were successfully prepared from poly(lactide-co-glycolide) using an ultrasonic nozzle installed in a Niro laboratory spray dryer. Process and formulation parameters were investigated with respect to their influence on microsphere characteristics, such as particle size, loading capacity, and release properties. Preparation of microspheres in yields of more than 50% was achieved using an ultrasonic atomizer connected to a stream of carrier air. Microsphere characteristics could be modified by changing several technological parameters. An increased polymer concentration of the feed generated larger particles with a significantly reduced initial release of the protein. Moreover, microspheres with a smooth surface structure were obtained from the organic polymer solution with the highest viscosity. Microparticles with a low BSA loading showed a large central cavity surrounded by a thin polymer layer in scanning electron microspheres. A high protein loading led to an enlargement of the shell layer, or even to dense particles without any cavities. A continuous in vitro release pattern of BSA was obtained from the particles with low protein loading. Glass transition temperatures (Tg) of the microspheres before and after lyophilization did not differ from those of the BSA loaded particles prepared by spray drying with a rotary atomizer. Analysis of the polymer by gel permeation chromatography indicated that ultrasonication had no effect on polymer molecular weight. Molecular weight and polydispersity of the pure polymer, placebo microspheres prepared by spray drying, and placebo microspheres prepared using the ultrasonic nozzle were in the same range. In conclusion, ultrasonic atomization represents a versatile and reliable technique for the production of protein loaded biodegradable microspheres without inducing a degradation of the polymer matrix. Particle characteristics can be modified by adjusting formulation parameters and atomization conditions in a simple manner.

Aerosols↗
PubMed2004

Leaching behavior of lead from ultrasonically treated MSWI fly ash.

This study was conducted to evaluate the effect of ultrasound widely used for extraction of contaminants and for synthesis of complexes, on extraction and stabilization of heavy metals in MSWI fly ash. Ten grams of fly ash was treated at 10 of liquid--solid (L/S) ratio with and without ultrasonic irradiation of 20 kHz. The extractability of Pb from fly ash was enhanced by ultrasound at the acidic condition. At neutral and alkaline conditions, however, ultrasound did not affect the enhancement of extractability. The results of the maximum availability leaching test (MALT) of the residues treated under various pH conditions with or without ultrasound indicated that the stability of Pb in the fly ash residues was enhanced after ultrasonic irradiation irrespective of treated pH conditions. However, there was a critical point on the enhancement of lead stability in the residues even though the extraction efficiency of Pb decreased gradually with increasing ultrasonic intensity during fly ash treatment. Ultrasonic irradiation was effective for phosphate stabilization of Pb in fly ash. Irrespective of leaching tests, less amount of Pb was leached out from the phosphate stabilized residues treated with ultrasound than without ultrasound. The extraction efficiency of Pb from fly ash decreased with increasing treatment time but the fractions available for leaching at MALT increased with increasing treatment time. Conclusively, although the effect of ultrasound on the extraction of Pb from fly ash highly depends on the pH condition of solvent, the stability of lead in the fly ash residues can be enhanced with ultrasonic irradiation.

Carbon↗
PubMed2004

Recovery of Salmonella spp. from raw produce surfaces using ultrasonication.

Fresh fruits and vegetables have been increasingly associated with outbreaks of foodborne illness. Microorganisms on the surface of raw produce may be difficult to remove for decontamination or microbial sampling due to entrapped or attached cells and porous surfaces. The objective of this study was to determine if ultrasonic treatment using 40 kHz with varying temperatures and agitation times can enhance removal and recovery of Salmonella spp. from raw produce surfaces. Strawberry, apple, and cantaloupe surfaces were spot inoculated with a fivestrain cocktail of nalidixic acid-resistant Salmonella spp. Produce were immersed in 0.1% buffered peptone water in either a Whirl-Pak bag for manual shaking (60 sec) or a sterile beaker for ultrasonic treatment (60 or 120 sec). Diluent temperatures of either 25 degrees C or 40 degrees C were used with these sampling protocols. Diluents were spiral plated onto tryptic soy agar supplemented with 50 ppm of nalidixic acid. No significant differences were observed between each Salmonella recovery method for each produce type. In this study, ultrasonic treatment using 40 kHz did not enhance recovery of Salmonella spp. from produce surfaces. The ultrasonic frequency, temperatures, and times used in this study did not enhance or diminish bacterial recovery. Additional research is still needed to determine the efficacy of other ultrasonic frequencies, diluents, and diluent temperatures for enhancing the recovery and enumeration of Salmonella spp. and other microorganisms from raw produce surfaces.

Bacterial Adhesion↗
PubMed1990

Physical properties of antibiotic aerosols produced by jet and ultrasonic nebulizers.

The drug stability and the physical properties of aerosol of five different antibiotics were compared for ultrasonic and jet-type nebulization. These antibiotics were used alone, as well as combined with betamethasone sodium phosphate and/or tyloxapol glycerol sodium bicarbonate. The parameters investigated were changes in appearance, pH, temperature, viscosity, specific gravity and the residual potency of the antibiotics. No significant change was shown in appearance, viscosity and specific gravity. Temperatures of the solutions in the ultrasonic nebulizer cup increased with time, though almost no change after 10 minutes in the jet nebulizer. For pH, with antibiotics alone in the ultrasonic nebulizer, some drugs showed an increase, and other drugs showed a decrease, while generally a little change in the jet nebulizer. For residual potency, one drug showed decreased potency in the aerosol, though it was increased in the remnant solution, in contrast, another drug showed a tendency to increased potency in the aerosol and decreased potency in the remnant solution in the ultrasonic nebulizer. In the jet nebulizer, drugs showed generally slight increased potency and no difference among drugs. It was suggested that, with ultrasonic nebulization, in some drugs the solvents were nebulized and the principal ingredient tended to remain behind, while in other drugs the opposite occurred so that the effects were not uniform.

Administration, Inhalation↗
PubMed1992

A comparison of 28kHz- and 160kHz- ultrasonic aerosolization of interferon-alpha.

The efficacy and utility of interferon (IFN) in prophylaxis and treatment of nasal infections have been evaluated in recent investigation. In our basic studies on aerosolization of IFN, we examined the effect of aerosolization on IFN-alpha activity utilizing an ultrasonic inhaler (NE-U05). The effect of ultrasonic treatment (28kHz) on IFN activity was also studied. IFN activity was determined by a conventional cytopathic effect inhibition assay. Although IFN-alpha activity was partially inactivated at a specific frequency of 28kHz, it was not affected by ultrasonic treatment (160kHz) from the ultrasonic inhaler. These results show that the aerosolization of IFN-alpha by the ultrasonic inhaler can be recommended for clinical use without inactivation of IFN-alpha activity.

Administration, Intranasal↗
PubMed2002

Effect of sonic and ultrasonic retrograde cavity preparation on the integrity of root apices of freshly extracted human teeth: scanning electron microscopy analysis.

Sonic and ultrasonic root-end preparation devices permit the preparation of conservative and straight cavities. However, microfractures and marginal chipping can occur due to the vibratory action of such instruments. The purpose of this study was to evaluate the effect of retrograde preparations by using sonic and ultrasonic tips on the integrity of root-end surfaces. Eighty, human anterior teeth were grouped according to size and treated as follows: treatment 1: root-end resection (RR) and root-end cavity preparation (RP) with KIS ultrasonic retrotip; treatment 2: RR and RP with Satelec S12/90 (no diamond coating) ultrasonic retrotip; treatment 3: RR and RP with a diamond-coated retrotip attached to a sonic device (Sonics); treatment 4: RR and RP with Satelec S12/90D (diamond coated) ultrasonic retrotip. The root-end surface topographies were assayed by means of polyvinylsiloxane impressions and epoxy resin replicas. SEM pictures of each sample were taken before and after preparation, and the images were evaluated by using an image processing and analysis system. The parameters evaluated were shape quality, presence of cracks, and marginal chipping. The results showed no statistically significant differences among anatomic groups, treatments, or tooth sizes (p > 0.05). Because treatment 3 removed more dental structure than the others did, its use on small teeth is inadvisable.

Apicoectomy↗
PubMed2000

Failure of ultrasonic vibration as a means of antigen retrieval in routine diagnostic immunocytochemistry.

It was recently reported that certain antigens can be retrieved from paraffin sections of formalin-fixed tissues by ultrasonication using either an expensive and sophisticated ultrasonic cell disrupter probe (cytokeratins 13 and 16) or an inexpensive and generally available ultrasonic cleaning bath (bcl-1). We wished to investigate the routine use of the latter method and therefore tried to retrieve from various tissues 11 antigens that usually require heat-mediated retrieval in citrate buffer. We applied ultrasonic vibration for periods of 30 seconds to 1.5 minutes in a cleaning bath containing citrate buffer or water, with and without the addition of heat, or for 1 minute in hot citrate buffer after microwaving for 10 minutes in the same buffer. Although a slight effect of ultrasound was noted for a few antigens, in no case did the immunostaining reach the level achieved after standard microwave heating in citrate buffer. We conclude that, under the conditions we used, ultrasonic antigen retrieval cannot be used for immunocytochemistry in a routine histopathology laboratory.

Antigens↗
PubMed2006

Ultrasonic technology facilitates minimal access thyroid surgery.

OBJECTIVES: Options for controlling the vasculature during thyroid surgery include suture ligatures, vessel clips, and bipolar cautery. Ultrasonic technology represents an alternative to conventional techniques in which the vessels are simultaneously sealed and divided. We sought to determine the safety and efficacy of thyroidectomy with ultrasonic technology. DESIGN: Nonrandomized, prospective analysis of a series of patients undergoing thyroidectomy at the Medical College of Georgia. METHODS AND MATERIALS: The records of 51 consecutive patients who underwent thyroid surgery between December 2004 and June 2005 were reviewed. Patients in whom ultrasonic technology (Harmonic-ACE, Ethicon Endo-Surgery, Cincinnati, OH) was used comprised the study population. RESULTS: Forty-four of 51 patients underwent thyroidectomy with the assistance of ultrasonic technology. There were 4 males and 40 females with a mean age of 43.5 +/- 15.8 years. Twenty-two patients had a total thyroidectomy, 18 underwent unilateral lobectomy, and 4 underwent completion thyroidectomy. The overall mean incision length was 5.0 +/- 2.6 (range 2-12) cm. A subgroup of patients underwent minimally invasive video-assisted thyroidectomy (n = 13) and had a mean incision length of 29.3 +/- 0.8 mm. There were no cases of permanent injury to the recurrent laryngeal nerve and no cases of persistent hypoparathyroidism. Blood loss ranged from 5 mL to 100 mL, with a mean of 26.7 +/- 21.8 mL. CONCLUSIONS: Ultrasonic technology facilitates thyroid surgery, particularly when a minimally invasive approach is undertaken. It reliably seals and divides the thyroid vasculature and will likely replace other methods of managing the thyroid blood supply.

Adult↗
PubMed2004

The ultrasonically activated scalpel versus bipolar diathermy for tonsillectomy: a prospective, randomized trial.

Among patients undergoing tonsillectomy, the ultrasonic scalpel has been reported to lead to less intraoperative blood loss than cold dissection, and less postoperative pain and faster recovery than monopolar electrocautery. However, the ultrasonic scalpel has not been compared with bipolar diathermy. The present study was a prospective, randomized, single-blind trial, comparing these two techniques with respect to postoperative pain. Twenty-one adults underwent tonsillectomy on one side using the ultrasonic scalpel, and on the other using bipolar diathermy. Pain scores were obtained on postoperative days 1, 2, 7 and week 3. There was no difference between the two treatments at any of the time points (P = 0.6047, 0.4018, 0.6047 and 0.5000, respectively). Inability to control bleeding with the ultrasonic scalpel resulted in the rescue use of an alternative technique of haemostasis in 14 cases. We conclude that the use of the ultrasonic scalpel in adult tonsillectomy is likely to be limited by its substantial costs and difficulties with haemostasis.

Adolescent↗
PubMed1989

Effect of heat and ultrasonic waves on the survival of two strains of Bacillus subtilis.

The combined effect of ultrasonic (20 KHz, 150 W) and heat treatment on the survival of two strains of Bacillus subtilis in three suspending media (distilled water, glycerol and milk) has been studied. When spores suspended in water or milk were subjected to ultrasonic waves before heat treatments a little or no decrease of the heat resistance was observed. However, both sporicidal agents applied simultaneously (thermo-ultrasonication) decreased by 63% (B. subtilis, var. niger-40) and 74% (B. subtilis ATCC 6051) the decimal reduction times for the heat treatment when the spores were suspended in glycerol and by 79% and 40%, respectively when suspended in milk. The thermo-ultrasonication of spores in water markedly reduced the heat resistance of them (between 99.9% and 70%) in the range 70-95 degrees C but the effect of the thermo-ultrasonication significantly diminished as the temperature of the treatment was approached to the boiling point of the water.

Animals↗
PubMed2005

A case of allergic contact dermatitis from propylene glycol in an ultrasonic gel, sensitized at a leakage skin injury due to transcatheter arterial chemoembolization for hepatocellular carcinoma.

A 63-year-old man with hepatocellular carcinoma consequent to chronic viral hepatitis C presented with severe dermatitis on the lower right side of the back after transcatheter arterial chemoembolization (TACE) via the 10th intercostal artery, because his hepatic artery had already collapsed due to repeated usage for TACE. The regional skin showed redness and hardness with pustules. Histologically, there was epidermal and appendage necrosis, as well as exocytosis of red blood cells. With a diagnosis of skin injury due to leakage of lipiodol ultrafluid, mitomycin, and epirubicin, administered via the 10th intercostal artery, onto the skin tissue, topical application of 0.06% fluocinonide-containing cream was prescribed. After several weeks of conservative local treatment, the leakage skin injury improved significantly, leaving pigmentation, hardness, and a small necrotic mass, as reported elsewhere (Honda T, Matsushima S, Fujii S, et al. A case of skin injury following transcatheter arterial chemotherapy through intercostal artery for hepatocellular carcinoma. Skin Res 2003; 2: 18-22). Subsequently, the patient again consulted the Dermatology Department with further dermatitis in an almost identical skin region on the right side of the abdomen (irregularly spreading erythematous and edematous eruptions with itching; Fig. 1). As he had undergone an ultrasonic examination 2 days earlier, allergic contact dermatitis from the ultrasonic gel was suspected. The contact dermatitis was treated with a topical corticosteroid hormone-containing ointment. Patch testing was performed with Ultra Phonic Conductivity Gel (Pharmaceutical Innovations Inc., Newark, NJ, USA), with which the patient had undergone a series of ultrasonic examinations, and Sono Jelly (Toshiba Medical Supply Co., Ltd., Tokyo, Japan) as a reference, as well as white petroleum as a negative control. A positive result was obtained for Ultra Phonic Conductivity Gel, whereas Sono Jelly was negative (Fig. 2a). Pharmaceutical Innovations Inc. kindly supplied the ingredients of the gel: propylene glycol (PG), preservative in PG, color in PG, thickener 1, and thickener 2. The company gave no further details about the preservative, color, and thickeners. Patch testing was performed using these five materials, resulting in a positive reaction for PG, preservative in PG, and color in PG. Thickeners 1 and 2 and lipiodol ultrafluid were negative (Fig. 2b). On the assumption that the causative chemical was PG, commercially obtained PG, free of preservative and color, was then patch tested (original, 10% aqueous, 1% aqueous, and 0.1% aqueous solutions), resulting in original strongly positive, 10% positive, and 1% and 0.1% weakly positive (Fig. 2c). The medical records showed that the patient had received 16 ultrasonic examinations with the same ultrasonic gel before the leakage skin injury. The 17th examination was performed 2 days after leakage dermatitis, and the 18th 3 months after the injury, when contact dermatitis occurred. The 19th examination was performed using Sono Jelly, which contains no PG, and no skin problems were observed.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Effect of ultrasonic stimulation on mRNA abundance of uncoupling protein (UCP) 2 and UCP 3 in gastrocnemius muscle of rats.

1. The hypothesis that ultrasonic stimulation upregulates uncoupling protein (UCP) 2 and UCP3 in gastrocnemius muscle by a different mechanism of exercise was investigated in Wister rats. 2. The ultrasnonic-stimulated group was given ultrasonic stimulation to the leg (1 MHz frequency, 1 W/cm2 intensity, 10 min continuously). 3. The exercise group was given exercise training by swimming for 10 min in plastic barrels filled with warm water. 4. After 3 h, rats were killed and the gastrocnemius muscle was removed rapidly, weighed and frozen in liquid nitrogen for real-time quantitative reverse transcription-polymerase chain reaction analysis. 5. In gastrocnenius muscles of ultrasonic-stimulated rats, UCP3 mRNA abundance was significantly increased 3.6-fold and UCP2 mRNA abundance was significantly increased 2.2-fold compared with control rats. 6. In gastrocnenius muscles of exercised rats, UCP3 mRNA abundance was significantly increased 3.5-fold compared with control rats, but no change in UCP2 mRNA abundance was observed. 7. Plasma free fatty acid (FFA) levels were also significantly increased in the ultrasonic stimulation group, as well as the exercise group, compared with the control group. 8. These findings show that ultrasonic stimulation lipolyses subcutaneous fat into FFA and glycerol and upregulates UCP2 and UCP3 mRNA by a mechanism different to that of exercise.

Animals↗
PubMed1997

External ultrasonic tumescent liposuction. A preliminary study.

BACKGROUND: External ultrasonic tumescent liposuction represents a new application of ultrasound energy to the standard tumescent liposuction procedure. Hoping to retain the in vivo properties of ultrasonic delivery while avoiding the growing number of invasive complications, external ultrasonic tumescent liposuction is a new technique with the potential of improving traditional tumescent liposuction therapy. OBJECTIVE: The purpose of this preliminary study was to evaluate the role of external ultrasonic tumescent liposuction as an adjunct to traditional tumescent liposuction. METHODS: Ten patients underwent standard tumescent liposuction with the addition of 10 minutes of preoperative ultrasound therapy applied to one-half of their targeted treatment regions. Both objective and subjective parameters were assessed during the subsequent side-by-side evaluations. RESULTS: Six of the 10 cases had a measurable increase in the amount of supernatant fat extracted per unit of aspirate volume from those regions pretreated with ultrasound energy. In five of the 10 cases, the operating physician noted slightly easier cannula maneuverability through adipose tissue on the ultrasound side. Roughly half of the patients had an improved postoperative course, with less swelling/edema, less bruising or ecchymoses, more skin retraction, and less postoperative pain/discomfort. CONCLUSION: The favorable results of this preliminary study warrant further investigation and research into external ultrasonic tumescent liposuction as an adjunct to the traditional tumescent liposuction procedure.

Abdominal Muscles↗
PubMed1987

The effect of subgingival debridement with hand and ultrasonic instruments on the subgingival microflora.

The effect of hand or ultrasonic instrumentation on the subgingival microflora of periodontal pockets was investigated. Pockets with probing depths of 6-9 mm were selected in 12 patients and were randomly assigned per patient to the experimental and control groups. After oral hygiene instruction, instrumentation of the experimental pockets was carried out either by ultrasonic or by hand instruments in a split-mouth design. The treatment effect on the subgingival microbiota was evaluated by microscopic and culture studies of subgingival plaque samples, while in addition, supragingival plaque, bleeding after probing and probing pocket depth were scored. Examinations were carried out before and 7, 21 and 49 days after treatment. The hand and ultrasonic treatments were equally effective in reducing probing pocket depths and bleeding scores. At the end of the experimental period, the probing depths of 54% of the hand-treated pockets and 43% of the ultrasonic-treated pockets were reduced to 4 mm or less while the bleeding scores were reduced to 29% and 22%, respectively. The analysis of microscopical and cultural data did not show any differences between hand and ultrasonic debridement. Both treatments reduced the microscopical counts of rods, spirochetes and motiles and reduced the total colony-forming units and number of black-pigmented Bacteroides and Capnocytophaga, resulting in a subgingival microbiota consistent with periodontal health.

Adult↗
PubMed2005

A new ultrasonic device in maintenance therapy: perception of pain and clinical efficacy.

BACKGROUND: A recently introduced piezo-driven ultrasonic device (Vector) generates longitudinal oscillations. As a result, the instrument tip moves parallel to the tooth surface. By avoiding vertical oscillations, maintenance treatment with the Vector device should be less painful than treatment with conventional systems. We investigated whether patients perceive treatment with the Vector device as less painful than with a conventional ultrasonic device, and whether the clinical efficacy of the Vector device is comparable with that of the conventional ultrasonic device in maintenance patients. MATERIAL AND METHODS: Thirty-eight maintenance patients with moderate to advanced periodontal disease took part in this prospective, randomized controlled clinical study. Each patients had to have at least two teeth with probing depths of >4 mm. They were treated either with Dentsply (n=22) at a reduced power setting or with the Vector device (n=16). The observation period was 6 months. Probing pocket depth, attachment level, and bleeding upon probing were assessed at six sites on each treated tooth by a blinded investigator Patient were asked to report perceived pain during instrumentation with a visual analog scale immediately after treatment, in the evening of the treatment day, and in the evenings 1 and 2 days after treatment. RESULTS: Bleeding on probing, probing depth, and attachment level improved in both instrumentation groups from baseline to month 6; however, there was no difference between the two instrumentation modalities. The patients perceived treatment with neither instrument as unpleasant, and their perception of pain intensity both during instrumentation and on the following days did not differ. CONCLUSION: In maintenance therapy, clinical efficacy of the vector device is comparable with that of conventional ultrasonic device. It makes no difference whether the ultrasonic device at a reduced power setting or the Vector device is used, since patients perceive both instruments as causing very little pain.

Adult↗
PubMed2005

Full-mouth ultrasonic debridement versus quadrant scaling and root planing as an initial approach in the treatment of chronic periodontitis.

AIM: To evaluate the clinical efficacy of (i) a single session of "full-mouth ultrasonic debridement" (Fm-UD) as an initial periodontal treatment approach and (ii) re-instrumentation of periodontal pockets not properly responding to initial subgingival instrumentation. METHODS: Forty-one patients, having on the average 35 periodontal sites with probing pocket depth (PPD) > or =5 mm, were randomly assigned to two different treatment protocols following stratification for smoking: a single session of full-mouth subgingival instrumentation using a piezoceramic ultrasonic device (EMS PiezonMaster 400, A+PerioSlim tips) with water coolant (Fm-UD) or quadrant scaling/root planing (Q-SRP) with hand instruments . At 3 months, all sites with remaining PPD> or =5 mm were subjected to repeated debridement with either the ultrasonic device or hand instruments. Plaque, PPD, relative attachment level (RAL) and bleeding following pocket probing (BoP) were assessed at baseline, 3 and 6 months. Primary efficacy variables were percentage of "closed pockets" (PPD< or =4 mm), and changes in BoP, PPD and RAL. RESULTS: The percentage of "closed pockets" was 58% at 3 months for the Fm-UD approach and 66% for the Q-SRP approach (p>0.05). Both treatment groups showed a mean reduction in PPD of 1.8 mm, while the mean RAL gain amounted to 1.3 mm for Fm-UD and 1.2 mm for Q-SRP (p>0.05). The re-treatment at 3 months resulted in a further mean PPD reduction of 0.4 mm and RAL gain of 0.3 mm at 6 months, independent of the use of ultrasonic or hand instruments. The efficiency of the initial treatment phase (time used for instrumentation/number of pockets closed) was significantly higher for the Fm-UD than the Q-SRP approach: 3.3 versus 8.8 min. per closed pocket (p<0.01). The efficiency of the re-treatment session at 3 months was 11.5 min. for ultrasonic and 12.6 min. for hand instrumentation (p>0.05). CONCLUSION: The results demonstrated that a single session of Fm-UD is a justified initial treatment approach that offers tangible benefits for the chronic periodontitis patient.

Adult↗
PubMed2004

In vitro assessment of dentinal permeability after the use of ultrasonic-activated irrigants in the pulp chamber before internal dental bleaching.

This in vitro study aimed to assess dentin permeability quantitatively after the use of different irrigants into the pulp chamber, with or without ultrasonic activation, before the application of an internal bleaching agent. Thirty maxillary anterior teeth, treated endodontically, were randomly assigned to six groups, according to the irrigant used: group I, distilled water; group II, 17% EDTA; group III, 1% sodium hypochlorite; for groups IV, V, and VI, respectively, the same solutions were used, but were ultrasonicated. In groups I, II, and III, the irrigant that filled the pulp chamber was left undisturbed for 15 s and was then aspirated; in groups IV, V, and IV, the irrigants were placed into the pulp chamber, ultrasonic-activated for 15 s, and were then aspirated. This sequence was repeated three times for all groups. Afterwards, for all groups, the pulp chamber was dried, filled with a bleaching agent, and sealed with glass ionomer cement. At each change of the whitening agent, these procedures were repeated. Then, the temporary restorations were removed, access cavities were cleaned, and teeth were immersed in a 10% copper sulfate aqueous solution, submitted to vacuum and immersed in a 1% rubianic acid alcohol solution. Copper ion penetration was revealed by the rubianic acid. After staining, roots were removed at the cemento-enamel junction (CEJ) and sectioned in a mesiodistal direction starting from the cervical plug level. The sections were thinned, observed under an optical microscope, the images were digitized, and copper ion penetration was measured in each section using a specific software. Means and SD were: group I, 2.41 (+/-1.45); group II, 5.22 (+/-1.79); group III, 8.32 (+/-2.55); group IV, 3.73 (+/-0.89); group V, 14.83 (+/-4.99); and group VI, 10.51 (+/-2.65). Statistical analysis using two-way anova and Tukey test showed that, regardless of the irrigant, ultrasonication increased dentinal permeability (P < 0.01). Comparing the overall effectiveness of the tested solutions, EDTA yielded the greatest increase in dentinal permeability (P < 0.01). Based on these results, it may be concluded that use of ultrasonic-activated irrigants in the pulp chamber, before the accomplishment of internal dental bleaching procedures, may result in a remarkable increase of dentin permeability, which may enhance the efficiency of the whitening agent.

Chelating Agents↗
PubMed1980

A relationship between ultrasonic intensity and changes in myocardial mechanics.

The effects of ultrasound on the mechanical properties of isometrically contracting rat papillary muscle have been studied as a function of the intensity of the ultrasonic irradiation. Each muscle was subjected to irradiation at 1.1., 2.2, and 3.3 W/cm2 at a frequency of 2.3 MHz. Ultrasonic irradiation caused heating in the vicinity of the muscle; thus it was necessary to separate the pure thermal and ultrasonic effects. After irradiation the bath temperature was increased so that the muscle reached the same temperature which occurred during ultrasonic irradiation. The mechanical parameters measured during the equivalent thermal procedure were compared with the parameters during irradiation. There was a significant (p less than 0.05) decrease in resting force which was significantly different from the equivalent thermal intervention and could be related to the ultrasonic intensity. Thus, the effect of ultrasound on rat papillary consists of two components, a thermal component which affects all parameters studied and a nonthermal component which affects only the diastolic force.

Animals↗