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At least 685 records · Page 38Linked to original sources

PubMed2000

Effects of ultrasonic dental scaling on pulp vitality in dogs: an experimental study.

We investigated whether dental pulpal damage is produced as a result of the application of an ultrasonic scaler commonly used in clinical veterinary dentistry. Using methods developed in preliminary studies, we examined six dogs. The radiographic thickness of the dentin and pulp cavity was measured. The ultrasonic scaler was applied to maxillary and mandibular premolar teeth for 30, 60, or 90 seconds, without the use of water as a coolant. The temperatures of the room, the pulp canal on untreated incisor teeth, the cheek, the gingival sulcus, and the dentin of the affected teeth were recorded using a probe with a thermistor attached to a resistivity meter and inserted in the dentin to a depth of 1 mm. Two weeks following scaling, the teeth were extracted for microscopic examination. In another dog serving as a control, the temperature of the dentin was increased to between 45 degrees C (113 degrees F) and 47 degrees C (117 degrees F) and the premolar teeth were removed for microscopic examination 15 days later. We concluded that the application of an uncooled ultrasonic scaler for 90 seconds did not increase the temperature of the dentin. However, damage comparable with acute pulpitis resulted as a consequence of the ultrasonic effect, similar to the effects produced by the 45-47 degrees C heat applied in the control animal.

Animals↗

PubMed1983

Ultrasonic and jet aerosolization of phospholipids and the effects on surface activity.

Surface active aerosols were produced from aqueous dispersions of mixed lipids (CLL), extracted from bovine lung lavage. Particle size distributions were measured as a function of humidity for two types of aerosol generators: ultrasonic and jet. Lipid dispersions before aerosolization were prepared by sonication in an ice bath and by mechanical vortexing. Over a range of high humidity greater than 60-70%, ultrasonic nebulization gave CLL aerosols with mass median aerodynamic diameters (MMAD) of 1.4 +/- 0.1 micron, compatible with predicted alveolar deposition fractions of 0.2-0.3 according to current deposition models. For humidities of 30-95%, jet nebulization gave MMAD values of 0.4-0.5 micron, which have lower predicted alveolar deposition. The surface pressure-time (pi - t) adsorption characteristics at 35 +/- 2 degrees C of CLL dispersions prepared initially by vortexing or sonication were not significantly affected by ultrasonic nebulization over a 1-2 h time period. In addition, the dynamic surface tension lowering of both kinds of CLL dispersion was not affected by ultrasonic nebulization (minimum surface tension less than 1 dyne/cm at 37 degrees C and 100% humidity). Current interest in the treatment of the respiratory distress syndrome (RDS) with exogenous surfactant replacement has focused largely on the delivery of surfactant replacement has focused largely on h delivery of surfactants to infants by tracheal instillation at birth. However, the ability to form multi-component surfactant aerosols with appreciable alveolar deposition fractions and high surface activity may help to expand the utility of replacement therapy to patients with aerated lungs.

Adsorption↗

PubMed1981

Acute physiological effects of ultrasonic vibrations on nervous tissue.

We investigated the acute effects of ultrasonically induced lesions on action potential conduction and blood flow in nervous tissues. A Cavitron ultrasonic surgical aspirator (CUSA) was used to emulsify small areas of cat thoracic spinal cord while hydrogen clearance, somatosensory evoked potentials, and vestibulospinal evoked potentials wee monitored. In addition, we examined the effect of direct and indirect application of the vibrating probe on rat sciatic nerves. The CUSA created localized lesions of the spinal cord, sparing the function and blood flow of immediately adjacent white structures. Histological studies revealed a sharp demarcation of the lesion sites with little morphological evidence of tissue injury beyond the borders of the lesions. The rat sciatic nerve experiments showed that, as long as the probe tip did not touch the nerve, ultrasonic vibrations had little effect on the nerve. These results suggest that the destructive effects of the ultrasonic vibrating probe are limited to a small volume at the probe tip. We conclude that, at low power levels sufficient to cause tissue emulsification at the probe tip, the CUSA does not acutely affect the function of nearby white matter. However, our results may not be extendable to higher intensity levels and do not rule out chronic effects.

Action Potentials↗

PubMed1994

Evaluation of the thrombolytic effect of tissue-type plasminogen activator with ultrasonic irradiation: in vitro experiment involving assay of the fibrin degradation products from the clot.

Previous studies show that the combined method using thrombolytic drugs and ultrasonic irradiation enhances the effect of thrombolysis in in vitro and in vivo experiments. However, the mechanism of the clot lysis was unclear. In previous studies the evaluation of the clot lysis effect was determined by the rate of decrease in clot weight or the decrease in radioisotope-labeled fibrinogen in the clot. However, it was unclear whether or not the fibrinogen in the clot was degraded. We measured quantitatively the fibrin degradation product, D-dimer (FDP-DD), produced from clots subjected to recombinant tissue-type plasminogen activator (rt-PA, 2.0 micrograms/ml), with and without ultrasonic irradiation. Two levels of continuous ultrasound were used, 300 kHz (100 V, 0.07 W/cm2) and 1 MHz (20 V, 0.4 W/cm2). The quantity of FDP-DD produced was 1.74 times at 300 kHz and 1.80 times at 1 MHz, greater than that measured in rt-PA solution without ultrasonic irradiation; clot lysis was not observed in normal saline with ultrasonic irradiation. Our experiment clarifies that the mechanism of clot lysis when subjected to a combination of drug and ultrasound leads to degradation of fibrin, allowing a quantitative measurement of the enhancement of clot lysis. A high correlation was observed between the FDP-DD produced from the clots and the rate of decrease in clot weight.

Analysis of Variance↗

PubMed2004

Control of gingival inflammation in a teenager population using ultrasonic prophylaxis.

Gingival inflammation is clinically characterized by gingival redness, swelling and increased tendency of bleeding of the soft tissue. Bacterial biofilm is the etiological agent. If, at this stage, the bacterial biofilm is removed and appropriate control methods are applied, remission of gingival inflammation occurs. This study evaluated the effectiveness of a single session of ultrasonic prophylaxis for the reduction of gingivitis in an adolescent population using the Plaque Index (PI) and Gingival Index (GI). The study sample consisted of 15 male adolescent students selected at a dentist's office of a public high school. Prior to treatment (baseline), plaque index (PI) and bleeding on probing (BOP) were recorded. The patients then received oral hygiene instructions and ultrasonic prophylaxis. Follow-up exams were made 15 and 30 days after the ultrasonic prophylaxis, again recording PI and BOP. The data were analyzed by the Student's t-test for dependent samples. Correlation analysis between presence of biofilm and bleeding on probing was also made using the Pearson correlation test. There was a statistically significant decrease in the plaque index and bleeding on probing between baseline and examinations at both 15 days and 30 days (p<0.05). However, the difference between the means at 15 and 30 days was statistically similar. The correlation analysis showed correlation between both parameters (p<0.05). The results indicate that a single session of ultrasonic prophylaxis associated to oral hygiene instructions is efficient to reverse gingivitis in adolescents.

Adolescent↗

PubMed1988

Hand versus ultrasonic instrumentation in the removal of endotoxins from root surfaces in vitro.

The goal of this study was to determine whether ultrasonic scalers are as effective as curettes in providing fibroblast attachment to the scaled root surfaces. Extracted, peridontally involved teeth were cut along the sagittal plane; then one half of the root was curetted, the other half ultrasonically scaled. In addition, monkey kidney fibroblasts were suspended in a petri dish containing root fragments of the tooth halves. At the same time, control dishes without fragments were mounted. All dishes were treated with radioisotopic techniques. There was no significant difference in fibroblast growth between peridontally involved root surfaces treated using curettes or ultrasonic scalers. Both treatments caused the roots to lose their toxicity. The limitations of ultrasonic scalers in terms of shape, size and awkward handling need to be considered when choosing the approach that best suits each case.

Animals↗

PubMed1991

The penetration of lavage solution into the periodontal pocket during ultrasonic instrumentation.

The purpose of this study was to evaluate the penetration depth of the water coolant for medicament lavage of an ultrasonic device into the periodontal pocket. Patients having teeth previously planned for extraction, and exhibiting probing depths 3 mm or greater were used in this study. A reference notch was placed on the tooth at the level of the gingival margin and the probing attachment level (PAL) was measured from the base of the notch to the base of the pocket. The ultrasonic device, with an EWPP tip and equipped with a reservoir of erythrocin dye colored coolant, was activated and moved in a vertical direction from the gingival margin to the apical extent of the pocket. The tooth was extracted and the penetration depth (PD) of the dye-colored water spray was measured from the reference notch to the apical limit of the stained subgingival plaque. The tooth was counter stained with methylene blue to determine the coronal extent of the connective tissue attachment. Pearsons' Product Moment Correlation Coefficient for the PAL and PD was calculated. Dye-stained root surface was observed along the full extent of the probe tip's penetration path. The dispersion of the dye-colored stain was localized to the area of the ultrasonic probe with very little lateral dispersion. The ultrasonic instrument may be an effective system to mechanically remove plaque and calculus at the same time as delivering a chemotherapeutic agent. The limited dispersion of the liquid dye would indicate that chemical plaque control with this delivery system is dependent upon thorough debridement with the instrument such that all affected surfaces are instrumented.

Connective Tissue↗

PubMed1996

Reduction of aerosols produced by ultrasonic scalers.

There is concern with decreased air quality and potential aerosol contamination in the dental operatory. This problem has been addressed by the Centers for Disease Control and Prevention, which recommends that all sources of blood-contaminated splatter and aerosols be minimized. One of the major sources of potential aerosol contamination in the dental setting is the ultrasonic scaler. This study looks at the use of a high volume evacuator attachment for the ultrasonic scaler handpiece. Artificial teeth were mock-scaled for 1 minute with and without the evacuator attachment. The mock scaling was performed within a plastic enclosure that had a 1 cm grid laid out on 4 sides. Scaling was performed 10 times each by 2 operators. An erythrosin solution was used for the ultrasonic scaler coolant with a coolant volume of 17.5 ml/min. The number of squares containing a red erythrosin spot were counted and considered to represent aerosol contamination. The high volume evacuator attachment produced a 93% reduction in the number of contaminated squares (chi squared significant at P < 0.05). There was no increase in heat transfer to a tooth analogue when the high volume evacuator attachment was used with the ultrasonic scaler as compared to the scaler without the evacuator attachment. It is felt that the high volume evacuator attachment is capable of significantly reducing the amount of aerosol contamination produced within the test system without increased heat transfer to the tooth.

Aerosols↗

PubMed2004

Influence of parameters on root surface roughness following treatment with a magnetostrictive ultrasonic scaler: an in vitro study.

BACKGROUND: This in vitro study aimed to evaluate the influence of different parameters, i.e., lateral force, instrument power setting, and the shape of the working tip, on the roughness of root surfaces following treatment with a magnetostrictive ultrasonic scaling device. METHODS: The study sample comprised a total of 102 extracted human molars, premolars, canines, and incisors. The samples were randomly divided into 10 equal units of 10 each for treatment with the ultrasonic device at a lateral force of 0.5 N and 2.0 N, a low and high instrument power setting, and with a straight and angulated shaped working tip. Twenty samples were treated manually using curets at a lateral force of 0.5 N and 2.0 N. Two samples were left untreated as controls. The mean (Ra) and maximum (Rmax) surface roughness of each sample was recorded. The statistical analysis was performed using analysis of variance (three-way ANOVA) at a level of significance of 5% (P < 0.05). RESULTS: The mean surface roughness (+/-SD) using different parameters ranged from 0.6 +/- 0.1 microm to 1.8 +/- 0.3 microm. The maximum surface roughness (+/-SD) was between 4.8 +/- 1.3 microm and 17.2 +/- 4.3 microm. The mean surface roughness (+/-SD) for samples treated with curets at a lateral force of 0.5 N was 0.5 +/- 0.0 microm and 0.4 +/- 0.1 microm at 2.0 N. The maximum surface roughness (+/-SD) was 3.7 +/- 0.8 microm at 0.5 N and 3.9 +/- 1.4 microm at 2.0 N. CONCLUSIONS: The findings of the present study indicate that the shape of the working tip and the lateral force significantly influence the mean and maximum surface roughness of root surfaces treated with a magnetostrictive ultrasonic scaling device. At any specific parameter, the surface roughness was significantly higher for the ultrasonic scaling device as compared to the hand curet.

Analysis of Variance↗

PubMed2006

Effects of Er:YAG laser and ultrasonic treatment on fibroblast attachment to root surfaces: an in vitro study.

BACKGROUND: The aim of this study was to analyze the effects of erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser and ultrasonic treatment on fibroblast attachment to periodontally diseased root surfaces. METHODS: Thirty single-rooted human periodontally involved teeth were included in this study. A total of 60 specimens were obtained from all selected teeth and were randomly assigned to the following three groups: group A, untreated control group; group B, ultrasonic group; and group C, Er:YAG laser at 160 mJ/pulse at 10 Hz group. All of the specimens were incubated in petri dishes with fibroblast suspension and observed by scanning electron microscopy. RESULTS: Laser-treated specimens showed a significantly higher cell density number, with a mean+/-SD of 3,720+/-316 cells/mm2. The ultrasonically treated group showed a lower cell density number, with a mean+/-SD of 658+/-140 cells/mm2. The untreated control group showed the lowest cell density number, with a mean+/-SD of 130+/-80 cells/mm2. Differences between all groups were significant (P<0.0001). CONCLUSION: The results of the study indicate that untreated control surfaces and ultrasonically treated surfaces exhibited a significantly lower number of attached cells compared to laser-treated specimens, which showed a significantly higher cell density number.

Adult↗

PubMed2007

Calculus removal with diamond-coated ultrasonic inserts in vitro.

BACKGROUND: Efficient calculus removal is a primary goal in periodontal therapy. Diamond-coated ultrasonic inserts (DIs) offer promise for improved scaling and were evaluated in vitro. METHODS: Extracted human teeth with moderate to severe calculus had areas of calculus ( approximately 5 x 5 mm) delineated with small burs. Each calculus area was treated under 2.5x magnification to the point of visible root cleanliness with sharp Gracey curets (hand instruments [HIs]), plain ultrasonic inserts (PIs), or ultrasonic inserts with fine-grit diamond coating; the latter two were used in a magnetostrictive ultrasonic instrument at a medium power setting. Each curet or insert was used for four teeth and then replaced by a new instrument. The time needed to clean each tooth/surface was recorded. The total area treated and the area of the residual calculus were calculated using an imaging analysis program. RESULTS: The mean time required for clinical calculus removal was 29.7 seconds for DIs, 91.9 seconds for PIs, and 49.8 seconds for HIs (all P <0.0001 from each other). Overall, the mean percentage of residual calculus was 6.3% for DIs, 5.4% for PIs, and 3.1% for HIs (significant differences between HIs and the other treatments). CONCLUSIONS: In vitro calculus removal was faster with DIs, followed by HIs and PIs. More residual calculus was found with the DIs; however, the 1% to 3% difference (93.7% clean versus 94.6% clean versus 96.9% clean with DIs, PIs, and HIs, respectively) does not seem to be clinically significant.

Coated Materials, Biocompatible↗

PubMed2001

Effects of changes in power setting of an ultrasonic aspirator on amount of damage to the cerebral cortex of healthy dogs.

OBJECTIVE: To determine the minimal ultrasonic aspirator pressure necessary to damage the cerebral cortex of healthy dogs. ANIMALS: 9 mixed-breed dogs. PROCEDURE: The study comprised 2 parts. In part A, 6 dogs were euthanatized immediately prior to the experiment. In part B, 3 dogs were anesthetized for recording of physiologic variables. In both parts, craniectomy and durotomy were performed to bilaterally expose the lateral aspect of the cerebral cortex. An ultrasonic aspirator was placed in contact with various areas of the cerebral cortex, and aspirator power was altered (10, 20, 30, and 40%). Duration of contact at each power was 5 and 10 seconds. Subsequently, gross morphologic and histologic damage was assessed in the cortex. RESULTS: Gross observations for all dogs were similar. At 10% power, visible or histologic damage was not evident in the cortex. At 20% power, the cortex was slightly indented from contact with the hand piece; however, cortical disruption was not evident. Cortical disruption was initially detectable at 30% power in some dogs and was consistently evident at 40% power in both sets of dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonic aspirator power of < 20% created minimal acute morphologic damage to the cortex. Power settings between 20 and 30% may superficially damage the cerebral cortex in healthy dogs, whereas 40% power consistently damages the cerebral cortex. Knowledge of the degree of damage to cerebral cortex caused by various amounts of power for ultrasonic aspirators will allow surgeons to avoid damaging normal brain tissues during surgery.

Animals↗

PubMed1987

Sound perception in the ultrasonic region.

The mechanism of ultrasonic perception was investigated electrocochleographically in guinea pigs (1) to compare AP responses in normal animals with those in kanamycin-poisoned animals with a damaged outer hair cell system; (2) and to analyse the masking property of continuous ultrasonic sound upon the AP evoked by burst stimuli within the auditory field. The study revealed several facts indicating the breakdown of cochlear sharp frequency analysis in the transduction of ultrasonic sound. We concluded that the sound perception in the ultrasonic region could be performed by the inner hair cell system without any enhancement or modulation of the outer hair cell system, which was regarded as an important process in a recent model of cochlear micromechanics.

Action Potentials↗

PubMed2004

Comparison of waterjet dissection and ultrasonic aspiration: an in vivo study in the rabbit brain.

OBJECT: The waterjet method of dissection has been shown to enable the precise dissection of the parenchyma vessels while preserving blood in cadaveric pig brains. The waterjet device has also been applied clinically to treat various diseases and disorders without complications. Evidence still remains to be gathered as to how the instrument performs in reducing surgical trauma, intraoperative blood loss, and postsurgical brain edema. In the present study the authors investigate these parameters in a comparison between waterjet dissection and ultrasonic aspiration in the rabbit brain in vivo. METHODS: Thirty-one rabbits received identical bilateral frontal corticotomies, which were created using the waterjet device or an ultrasonic aspirator. The animals were killed 1, 3, or 7 days, or 6 weeks after surgery and their brains were processed for immunohistological analysis. Blood vessel preservation, intraoperative hemorrhage, postsurgical brain edema, and posttraumatic microglial and astoglial reactions were evaluated. Only in animals subjected to waterjet dissection were preserved vessels observed within the corticotomies. In addition, less intraoperative bleeding occurred in animals in which the waterjet was used. The microglial reaction was significantly reduced by waterjet dissection compared with ultrasonic aspiration; however, no difference in edema formation or astrocytic reactivity was observed. CONCLUSIONS: These results demonstrate that waterjet dissection appears to be less traumatic than ultrasonic aspiration with respect to intraoperative hemorrhage and postoperative microglial reactivity in the rabbit model. Nevertheless, no difference in edema formation could be demonstrated. It remains to be proven that the observed differences are of clinical relevance.

Animals↗

PubMed2006

Ultrasonic bone curettage for optic canal unroofing and anterior clinoidectomy. Technical note.

Extradural unroofing of the optic canal and subsequent mobilization of the optic nerve is a useful technique in the surgical treatment of parasellar tumors; however, the drilling procedure itself is associated with the risk of optic nerve damage. A safer technique would certainly be beneficial. The ultrasonic bone curette is a device developed in Japan for safer bone removal. Its use in intradural anterior clinoidectomy and opening of the internal auditory meatus has been reported before. In this article the authors describe their experience in using this device for extradural unroofing of the optic canal in patients with parasellar tumors. Between March 2002 and November 2004, the aforementioned technique was used in the treatment of eight patients with parasellar tumors. After undertaking a frontotemporal craniotomy and orbital osteotomy, an ultrasonic bone curette was used to unroof the optic canal via an epidural approach; in five cases anterior clinoidectomy was added subsequently. Using an ultrasonic bone curette, unroofing of the optic canal was completed safely and required much less expertise than that required for standard drilling. The mortality and major morbidity rates were 0%. The visual function outcome was satisfactory, with the overall visual status improving in all seven patients in whom this symptom was present preoperatively. The ultrasonic bone curette makes the unroofing of the optic canal safer and easier, possibly improving the visual outcome of patients undergoing surgery for parasellar tumors.

Craniotomy↗

PubMed1999

Tumour cell dispersion by the ultrasonic aspirator during brain tumour resection.

Ultrasonic aspirators are commonly used to resect brain tumours because they allow safe, rapid and accurate removal of diseased tissue. Since ultrasonic aspirators generate a spray of aerosolized irrigating fluid around the instrument tip, we questioned whether this spray might contain viable tumours cells that could contribute to intraoperative spread of tumour fragments. To test this hypothesis, we collected the spray produced during the resection of nine brain tumours with an ultrasonic aspirator and semi-quantitatively analysed it for tumour presence. The aerosolized irrigation fluid was found to contain intact tumour cells or clumps of tumour cells in all nine instances, and there was a trend of increasing tumour cell dispersion with increasing ultrasonic aspiration times. Further examination is required to determine if this intraoperative dispersion of apparently viable tumour fragments contributes to local neoplasm recurrence.

Brain Neoplasms↗

PubMed1975

[Influence of biophysical factors on redox processes and biological oxidation. 20. Tissue temperatures under ultrasonic administration].

The temperature differences obtaining in the subcutaneous tissues directly below the zone exposed to ultrasonic irradiation, the liver an the myocardium of white rats were measured during and after ultrasonic treatment. The only rise in temperature was observed in the tissues located below the field of ultrasonic irradiation after the second minute. The temperature drop in each of the three types of tissue examined is a characteristic feature. This paradoxical effect produced by ultrasonic intensities of 0.2, 0.6, 1.0, and 1.6 watt/cm-2, which has not as yet been described in the literature, may be explained by the control mechanisms keeping the internal body temperature relatively constant and, in particular, by those mechanisms of temperature regulation which are controlled by the biogenic amines.

Animals↗

PubMed2001

Application of ultrasonic scalpel in gynecologic operative laparoscopy.

OBJECTIVE: To investigate the applied value of the ultrasonic scalpel in gynecologic operative laparoscopy. METHODS: Gynecologic operations were performed using the ultrasonic scalpel under laparoscopy. Operative bleeding and time, perioperative body temperature and hemogram, and tissue damage were observed. RESULTS: Forty-two cases of benign gynecologic diseases were treated with the ultrasonic scalpel under laparoscopy. Among them, there were 4 hysterectomies, 9 ovarian cystectomies, 18 salpingotomies, 4 ectopic pregnancies, 3 myomectomies, 3 adhesiolysis and 1 adnexectomy. The amount of operative bleeding, operating time and the tissue injury were related to the type of operation. The minimual operative bleeding amount, operating time, depth of tissue necrosis, tissue injury score and fibrin deposition score were 24.77 +/- 4.71 ml, 23.39 +/- 3.01 min, 0.22 +/- 0.10 mm, 0.98 +/- 0.21 and 0.38 +/- 0.26, respectively. The maximal operative bleeding amount, operating time, depth of tissue necrosis, tissue injury score and fibrin deposition score were 166.7 +/- 47.18 ml, 127.2 +/- 16.99 min, 0.35 +/- 0.20 mm, 1.25 +/- 0.20 and 0.81 +/- 0.29, respectively. The levels of body temperature, white blood cells and hemoglobin before and after the operations were not statistically different (P > 0.05) except for hysterectomy (P < 0.05). CONCLUSION: The ultrasonic scalpel can be safely applied for gynecologic operative laparoscopy and should be used widely.

Blood Loss, Surgical↗