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PubMed2004

Inactivation of Saccharomyces cerevisiae by ultrasonic irradiation.

We have investigated the inactivation of Saccharomyces cerevisiae (yeast cells) by ultrasonic irradiation. The amplitude on the vibration face contacting the sample solution was used as an indication of the ultrasonic power intensity. The effects of the amplitude on the vibration face and the initial cell numbers on the sonolytic inactivation of yeast cells have been investigated using a horn-type sonicator (27.5 kHz). The inactivation of the yeast cells by ultrasonic irradiation shows pseudo first-order behavior. The inactivation rate constant varied from 0.0007 to 0.145 s(-1) when the amplitude on the vibration face was in the range of 1-7 microm(p-p). The change in the inactivation rate constant as a function of the amplitude on the vibration face was similar to that of the OH radical formation rate under the same conditions. The threshold of this sonicator was 3 microm(p-p) with the amplitude on the vibration face. The initial cell numbers (from 10(2) to 10(5) mL(-1)) had an influence on the inactivation of the yeast cells by ultrasonic irradiation. The inactivation rate constants varied from 0.023 to 6.4 x 10(-3) s(-1), and the inactivation by ultrasonic irradiation was fastest at the lowest initial cell numbers. In a squeeze-film-type sonicator (26.6 kHz), 90% inactivation of the yeast cells was achieved by ultrasonic irradiation for 60 min.

Animals↗
PubMed2004

Inactivation of Escherichia coli by ultrasonic irradiation.

Ultrasonic inactivation of Escherichia coli XL1-Blue has been investigated by high-intensity ultrasonic waves from horn type sonicator (27.5 kHz) utilizing the "squeeze-film effect". The amplitude of the vibration face contacting the sample solution was used as an indication of the ultrasonic power intensity. The inactivation of the E. coli cells by ultrasonic irradiation shows pseudo first-order behavior. The inactivation rate constant gradually increased with increasing amplitude of the vibration face and showed rapid increase above 3 microm (p-p). In contrast, the H2O2 formation was not observed below 3 microm (p-p), indicating that the ultrasonic shock wave might be more important than indirect effect of OH radicals formed by ultrasonic cavitation in this system. The optimal thickness of the squeeze film was determined as 2 mm for the E. coli inactivation. More than 99% of E. coli cells was inactivated within 180-s sonication at the amplitude of 3 microm (p-p) and 2 mm of the thickness of the squeeze film.

Escherichia coli↗
PubMed1994

Treatment of subgingival implant surfaces with Teflon-coated sonic and ultrasonic scaler tips and various implant curettes. An in vitro study.

Removal of plaque and calculus by means of sonic and ultrasonic scalers causes considerable damage to implants. With a view to avoiding the aggressive effects of these instruments, an experimental study was carried out for which conventional sonic and ultrasonic scalers were coated with Teflon. The effects of these instruments on implant surfaces was then compared with that of plastic and metal implant curettes. Stereo-microscopy, scanning electron microscopy and surface profilometry were used to detect and record damage to implant surfaces and changes in surface roughness. Generation and propagation of heat in subgingival simulation of use of sonic and ultrasonic scalers were also recorded by means of temperature measurements at the implant surface. The results revealed that no discernible damage was caused by Teflon-coated sonic and ultrasonic scalers or implant curettes made of plastic on smooth titanium surfaces. Instrument material residues were found on rough implant surfaces. It was not the intention of this study to provide an analysis of the prerequisites for the cleaning of rough implant surfaces, but rather to determine what type of damage is to be expected when contact is made with smooth and rough surfaces unintentionally. Temperature measurements during the subgingival use of sonic and ultrasonic scalers indicated satisfactory functioning of the cooling system. Coating of sonic and ultrasonic scaler tips with Teflon thus facilitates the use of high-frequency instruments to achieve professional cleaning of implants.

Dental Implants↗
PubMed2000

Lack of antimicrobial effect on periodontopathic bacteria by ultrasonic and sonic scalers in vitro.

BACKGROUND: The purpose of this study was to assess the antimicrobial effects of a sonic and ultrasonic scaler generally used for subgingival scaling on gram-negative and gram-positive periodontopathic bacteria. METHOD: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Campylobacter rectus, or Peptostreptococcus micros were suspended in Schaedler's broth medium and treated by a sonic or a magnetostrictive ultrasonic scaler for 30 s and 150 s in vitro. Bacterial suspensions treated by an ultrasonic cell disruptor served as a positive control and untreated bacterial suspensions served as a negative control. Following sonication, samples were serially diluted, streaked on blood agar plates and incubated for 2-5 days at 37 degrees C. RESULTS: Treatment by the sonic or ultrasonic scaler for up to 150 s did not reduce the viability of any of the tested periodontal pathogens. Compared to untreated controls, the viability of A. actinomycetemcomitans and P. gingivalis was significantly (p<0.05) reduced only following ultrasonication with the cell disruptor after 30 s (0.72 and 0.54 log CFU/ml, respectively) and of A. actinomycetemcomitans, P. gingivalis, C. rectus, and P. micros after 150 s (1.98, 1.34, 1.95 and 1.98 log CFU/ml, respectively). CONCLUSION: The data of the study may indicate that the assessed sonic and ultrasonic scaler used for subgingival debridement do not result in killing of the tested periodontal pathogens.

Colony Count, Microbial↗
PubMed2003

Evaluation of the ultrasonic dissector in thyroid surgery. A prospective randomised study.

BACKGROUND: The use of ultrasonic dissectors in endoscopic surgery has proved to be of value, particularly for the prevention of bleeding and the reduction of electrical internal burns. This prospective randomised study was performed in order to evaluate the efficacy, security and cost of using the ultrasonic hook in thyroid surgery. METHODS: Thirty-four consecutive euthyroid patients with multinodular goitre for whom a total thyroidectomy was indicated, were randomly assigned either to group I, Ultracision or to group II, conventional hemostasis. Pre-, peri-, and postoperative biochemical, clinical, surgical and economical variables were compared between both groups. RESULTS: The use of the ultrasonic hook resulted in a significant reduction in operating time, blood loss, and maybe in "transitory hypoparathyroidism"; postoperative analgesic consumption was also reduced in this group. Considering the cost, the ultrasonic hook was no more expensive than conventional hemostasis, as long as a minimum of 15 patients shared the initial unit cost of the device. CONCLUSION: Even if the use of the ultrasonic dissector is not of major interest in terms of patient management or cost-saving in the context of total thyroidectomy, essential advantages reside in significant reductions of operating time, blood loss and organ injury, (particularly parathyroid). The reduced operating time undoubtedly represents a positive feature of the ultrasonic dissection technique.

Goiter, Nodular↗
PubMed2006

Healing following ultrasonic debridement and PVP-iodine in individuals with severe chronic periodontal disease: a randomized, controlled clinical study.

OBJECTIVE: Antiseptics and antibiotics delivered either locally or systemically have been used as an adjunct to scaling and root planing procedures in order to control the subgingival biofilm and thereby enhancing the treatment outcome. The results presented in the literature are, however, inconclusive. Povidone-iodine (PVP-iodine) has a bactericidal effect and is effective against most bacteria, including putative periodontal pathogens. The aim of the present study was to evaluate the clinical effect of PVP-iodine as an adjunct to ultrasonic scaling in the treatment of severe chronic periodontitis. MATERIAL AND METHODS: Twenty patients were recruited to the study. Each test site and the related quadrant were randomly assigned to one of four different treatment modalities: ultrasonic scaling + subgingival irrigation with 0.5% PVP-iodine for 5 min/tooth, ultrasonic scaling + subgingival irrigation with sterile saline solution for 5 min/tooth, subgingival irrigation with sterile saline solution for 5 min/tooth, and subgingival irrigation with 0.5% PVP-iodine for 5 min/tooth. The individuals were followed longitudinally for 6 months. RESULTS: The present study showed that non-surgical periodontal therapy by means of an ultrasonic device was effective in attaining a healthy periodontal status in patients with severe periodontal lesions. No additive effect was found when PVP-iodine was included. CONCLUSIONS: Ultrasonic debridement using Odontogain is effective in controlling infection in patients with severe chronic periodontitis. PVP-iodine does not add any clinical benefit to the ultrasonic debridement alone under these circumstances.

Adult↗
PubMed2001

Ultrasonic irradiation for blue-green algae bloom control.

A novel application of ultrasonic irradiation for rapid control of blue-green algae (BGA) bloom was investigated. Potassium iodide (KI) experiments demonstrated that frequency and input power are the major factors that affect the ultrasonic irradiation intensity. Short exposure (3 s) to ultrasonic irradiation (120 W input power, 28 kHz) effectively settled naturally growing BGA suspension. Electron microscopy reconfirmed that sedimentation was caused by the disruption and collapse of gas vacuoles after ultrasonic exposure. Moreover, even after 5 min of exposure to ultrasonic irradiation (1200 W input power, 28 kHz) the microcystin concentration in BGA suspensions did not increase. For the same input power (120 W), a lower frequency (28 kHz) was found to be more effective in decreasing the photosynthetic activity of BGA than a higher frequency (100 kHz). The sonicated cells did not proliferate when they were cultured in conditions that simulated the bottom of water bodies (i.e. with limited light (400 lx) or no light and non-aerated or aerated (1 l min-1)). Furthermore, ultrasonic irradiation did not only collapse gas vacuoles and precipitate BGA, but may have also inflicted damage on the photosynthetic system of the BGA.

Cell Culture Techniques↗
PubMed2001

Removal of fractured posts using ultrasonic vibration: an in vivo study.

The purpose of this study was to determine the effectiveness of ultrasonic vibration in the removal of fractured posts from teeth under true clinical conditions. Thirty patients (16 men and 14 women with a mean age of 51 yr, SD 13.13) had ultrasonic vibration applied to the side of a fractured post fragment after creation of a small gutter around the fragment. A piezoelectric ultrasonic scaler was used to apply the vibration for two 15-s periods and then 30-s periods until the post fragment became loose. There was a significant correlation (r = 0.52, p = 0.003) between the cemented length of post fragment (mean length 3.8 mm, SD 1.39) and the time of ultrasonic vibration application (mean time 2.05 min, SD 1.62), but the correlation between post diameter and ultrasonic time did not reach statistical significance (r = 0.35, p = 0.059). The mean ultrasonic time was approximately 25% of that found in previous studies on post removal from extracted teeth probably because of suboptimal cementation of posts in the clinical situation.

Adult↗
PubMed2002

Novel method for driving the ultrasonic motor.

This paper reports a novel driving method for an annular plate-type ultrasonic motor. Instead of the direct current/alternating current (DC/AC) converter type driver using conventional electromagnetic transformer, a compact disc-type piezoelectric transformer is used to obtain high voltage output for driving the ultrasonic motor. The piezoelectric transformer is operated in the radial vibration mode at resonance frequency close to the resonance frequency of the ultrasonic motor. Later, it was found that the piezoelectric transformer could drive the ultrasonic motor, even if their resonance frequencies are not exactly the same by incorporating the matching network in the circuit. The maximum speed of the ultrasonic motor obtained by using this driving method is over 300 rpm. It is believed that the results of this study will have impact on the integration and miniaturization of the ultrasonic motor and its driving circuit.

Acoustics↗
PubMedDate not supplied

Use of an ultrasonically activated scalpel for splenectomy in 10 dogs with naturally occurring splenic disease.

OBJECTIVE: To evaluate the safety and efficacy of an ultrasonically activated scalpel for performing splenectomy, with minimal ligation, in dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: Dogs (10) with naturally occurring splenic disease. METHODS: Between October 2003 and February 2004, splenectomy was performed using an ultrasonically activated scalpel and a double seal method, in 10 dogs with naturally occurring splenic disease. Time for splenectomy and number of ligatures required were recorded. Intraoperative hemostasis, device ease of use, postoperative hemorrhage, and short-term survival were evaluated. RESULTS: Mean operative time for splenectomy, exclusive of celiotomy and closure, was 18 minutes (range, 8-25 minutes). The mean number of ligatures needed to perform splenectomy was 1 (range, 0-2 ligatures). One dog hemorrhaged from the splenic vein after ultrasonic scalpel transection of a vessel >5-mm diameter and required a ligature. The ultrasonic scalpel was easy to use, with a minimal learning curve. None of the dogs had postoperative abdominal hemorrhage; 9 dogs were discharged and 1 dog was euthanatized because of septicemia. CONCLUSION: Ultrasonic activated scalpel may be used to achieve efficient and safe hemostasis of the splenic vascular pedicle in dogs with minimal need for vascular ligation. CLINICAL RELEVANCE: Ultrasonic scalpels can be used to perform splenectomy in dogs with naturally occurring splenic disease.

Animals↗
PubMed1992

Effects of ultrasonic and sonic scalers on dental plaque microflora in vitro and in vivo.

The effects of ultrasonic and sonic scalers on the subgingival microflora were investigated in vitro and in vivo. In the in vitro investigation, 27 plaque samples collected from periodontal pockets were submitted to ultrasonic and sonic vibrations for 10, 30 and 60 s. Bacterial suspensions were examined by darkfield microscopy to detect qualitative changes and cultured to evaluate the total number of cultivable bacteria. Microscopic counts following both instrumentations showed a decrease in the proportions of spirochetes and motile rods and an increase in the % of coccoids and rods. The changes were directly related to the time-period of instrumentation. Comparison between both types of instrumentation showed significant differences and more pronounced changes were observed with the ultrasonic than the sonic scaler. Spirochetes and motile rods were reduced to approximately 0.1% after ultrasonic treatment versus 24.7% after sonic instrumentation. Cultural observations showed a marked increase in total number of colony-forming units following both treatments. The clinical investigation included 66 periodontal pockets which were instrumented subgingivally for 10 and 30 s with ultrasonic or sonic scalers. Qualitative changes were similar to those observed in vitro, i.e., reduction in spirochete and motile rod counts as well as the other morphotypes with an increase in coccoid cells. Total counts of bacteria were reduced following debridement. No difference in the microscopic or cultural data was found between ultrasonic and sonic instrumentation.

Adult↗
PubMed1991

An in vitro comparison of root canal content extrusion using ultrasonic and hand instrumentation.

The purpose of this study was to evaluate apical extrusion of root canal content using ultrasonic and hand instrumentation. Forty-nine tooth models were fabricated with clear resin. Each model contained a canal in the center. Each tooth model was mounted in a plastic cube (1 x 1 x 2 cm) with white dental plaster so that the coronal 2-3 mm of the model was exposed for instrumentation. Methylene blue dye with glycerin was used as a marker for root canal content. The study consisted of three groups. In group I, Enac ultrasonic instrumentation was used 1 mm from the apex; in group II, Enac ultrasonic instrumentation was used 3 mm from the apex; in group III, K files were used with a push-pull instrumentation technique, 1 mm from the apex. After instrumentation the resin models were extracted and the plaster blocks were sectioned through the long axis of the models. Photographs were made of the area of apical leakage and the amount of dye penetration was measured using a planimeter. There were no differences between hand instrumentation and both ultrasonic groups. At p less than 0.05, ultrasonic instrumentation 3 mm from the apex leaked significantly more than the ultrasonic instrumentation 1 mm from the apex.

Dental Cavity Preparation↗
PubMed1991

Transdermal delivery of insulin by ultrasonic vibration.

Ultrasonic vibration has been used to deliver insulin through the skin of hairless mice fasted overnight and partially immersed in an aqueous solution of insulin (20 units mL-1). The skin surface was exposed to ultrasonic vibration in two ultrasonic energy ranges (3000-5000 Pa and 5000-8000 Pa) at 48 kHz for 5 min. Blood glucose concentration was measured before and after exposure to insulin and ultrasonic vibration. In the group subjected to the lower energy vibrations, blood glucose fell rapidly to reach 34 +/- 11.9% of control values in 120 min, while when the animals were exposed to higher energy vibrations, the fall in blood glucose was 22.4 +/- 3.9% of control values at 120 min. The values remained low for the length of the experiment (240 min). Those exposed to insulin alone or ultrasonic vibration alone revealed no significant change in blood glucose concentration. It is postulated that ultrasonic vibration may alter skin permeability resulting in the absorption of insulin. That the blood glucose decrease was greater at the higher of the two energy ranges, suggests this factor could control insulin delivery.

Administration, Cutaneous↗
PubMed1988

Ultrasonic propagation properties (@ 100 MHz) in excessively fatty rat liver.

The effects on the ultrasonic propagation properties of livers of the addition of 1% orotic acid to rat diets were examined. In rats, dietary orotic acid exerts several effects on lipid metabolism; its overall consequence is that excessively high hepatic fat concentrations are built up over a short period of time, thus making this an ideal model to study the ultrasonic propagation properties as a function of sequential development of fatty liver. Over a 16-day period on the orotic acid diet, the supplemented rat liver lipid concentrations increased from a normal range of 2%-4% to the lower 20's%; hepatic water concentration decreased from a normal value of approximately 70% to approximately 50%; total protein concentration decreased slightly from a normal range of 17%-20% to 11%-16%; and rat liver weight increased from approximately 11 g to around 20 g. Ultrasonic attenuation coefficient and speed were assessed in liver tissue with the scanning laser acoustic microscope at 100 MHz. As hepatic lipid increased, ultrasonic attenuation at 100 MHz increased temporally from a normal range of 12-14 dB/mm to a maximum of 54 dB/mm and ultrasonic speed decreased from a normal range of 1553-1584 m/s to a minimum of 1507 m/s. Multivariant linear regression was used in the analysis of covariance to fit the least-squares estimates to the linear regression model. Strong correlates of ultrasonic speed with both water concentration and fat concentration in the liver were observed.

Animals↗
PubMed1987

In vitro comparison of DeVilbiss jet and ultrasonic nebulizers.

Output, droplet size (by laser instrument), and nebulization time have been compared in vitro for eight individual ultrasonic nebulizers (DeVilbiss Pulmosonic) and eight individual jet nebulizers (DeVilbiss 646), the latter operated by compressed air at flows of 6 and 12 L/min. A solution of hypertonic (7 percent) saline was nebulized. The ultrasonic nebulizer retained a higher "dead" volume of solution on completion of nebulization (p less than 0.05), but the increase in saline concentration was less marked than for the jet (p less than 0.01). The mass of NaCl released as aerosol was similar for the ultrasonic and for the jet at 6 L/min but was increased for the jet at 12 L/min (p less than 0.05). There was a fivefold interindividual variation in output for the ultrasonic. Droplet mass median diameters for the ultrasonic (mean 5.4 micron) were slightly lower than those for the jet at 6 L/min (mean 6.0 micron, p less than 0.05) but were higher than those for the jet at 12 L/min (mean 3.7 micron, p less than 0.01). The ultrasonic emitted virtually no droplets less than 2 micron diameter and may be unsuitable for applications requiring high yields of fine particles for delivery to the peripheral lung regions.

Aerosols↗
PubMed2005

Thermal injury through intraradicular heat transfer using ultrasonic devices: precautions and practical preventive strategies.

BACKGROUND: The use of ultrasonic energy is a highly efficient method of removing obstructions and cements within the root canal space when re-treatment or rehabilitation of that ultrasonic energy dislodges and removes cemented objects from the bonded interface of the canal wall. When using this method, there is less potential for structural loss or root damage and significantly less operator stress than when using other methods. CASE DESCRIPTIONS: There is little evidence in published research of the considerable heat transfer that occurs during use of ultrasonic devices to remove posts, pastes and separated instruments in teeth. The authors present three cases of patients who experienced serious burn injuries during application of ultrasonic energy for restorative dentistry. The authors also offer techniques and strategies for safe and effective use of ultrasonic devices. CLINICAL IMPLICATIONS: On the basis of the best available evidence, the authors recommend strategies to provide safe and effective therapy while using ultrasonic devices in intraradicular obstruction removal. The intent of the suggested protocols is to provide advanced and sophisticated therapies in a safe and regulated manner with patient safety as an overriding priority.

Adult↗
PubMed2002

In vivo ultrasonic debridement forces in bicuspids: a pilot study.

BACKGROUND: Hand instruments lead to application of excessive forces, resulting in extensive root substance removal. Ultrasonic debridement primarily removes accretions from root surfaces. However, there is a lack of information on procedural aspects of ultrasonic debridement. The purpose of the present study was to assess the forces applied by different therapists during ultrasonic root surface debridement of bicuspids in periodontal patients in vivo. METHODS: Ten dentists and 10 dental hygienists each debrided 1 aspect of a bicuspid with moderate chronic periodontitis using an ultrasonic curet. The forces applied were recorded using a piezo-electric receiver built into the handle of the ultrasonic curet, an electronic transducer, and an analogous writer. The force recordings were converted from millivolts into Newtons (N). Mean positive and negative forces were calculated for each therapist, and t tests were used to assess differences in these forces between dentists and dental hygienists. RESULTS: The results showed that the mean positive force applied by dentists was 1.00 N (range 0.53 to 1.34 N). The corresponding mean value for dental hygienists was 0.77 N (range 0.20 to 1.22 N). The mean root debridement time was 110.2 seconds (range 38 to 165 seconds) for dentists and 90.8 seconds (range 38 to 244 seconds) for dental hygienists. The mean percentage of total debridement time used for positive force application by dentists was 76.1%, and for dental hygienists 63.9%. Negative forces impacting on the periodontal soft tissues were also recorded. These negative forces reached a mean of 0.16 N for dentists and 0.31 N for dental hygienists. CONCLUSIONS: From these observations, it may be concluded that application of ultrasonic debridement therapy is highly subjective, and that dentists and dental hygienists may not be adequately trained to use these instruments optimally.

Bicuspid↗
PubMed2003

Effect of loading on the vibration characteristics of thin magnetostrictive ultrasonic scaler inserts.

BACKGROUND: The ultrasonic scaler market has seen an increase in availability of thin inserts for periodontal pocket access. While such thin inserts may have advantages in negotiating the periodontal pocket, the relatively narrow structure may be prone to damping under load. The purpose of this study was to assess the vibration characteristics under load of thin, straight, ultrasonic scaler inserts. METHODS: Five types of thin inserts were each obtained from three manufacturers and were operated using an ultrasonic generator at medium power and low water. The displacement amplitude of the scaling tip was measured via a scanning laser vibrometer (SLV). Increasing forces up to 1.0 N were applied either to the base of the tip (up through its center) or while it was loaded from the side. Displacement measurements were obtained using the SLV under these loading conditions. RESULTS: Under loading, there was a drop in displacement amplitude of all tips. Furthermore, loading of the tips resulted in large variations of displacement amplitudes recorded. The mean tip displacements recorded ranged from 10 to 30 microm when unloaded and 7 to 25 microm when loaded. The fundamental frequency of the ultrasonic tips' oscillation was at 30 kHz. However, loading resulted in the production of additional subharmonic frequencies in the region of 6 to 10 kHz. CONCLUSIONS: Thin ultrasonic scaler tips are susceptible to loading. This results in a reduction in the displacement amplitude that shows variation not only between tips of different design but also between those of the same design made by the same manufacturer. Clinicians and researchers should be aware of this variability, which may influence both clinical procedures and future research with thin ultrasonic scaling tips.

Dental Enamel↗