The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with... more The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with the tooth surfaces. The aim of this study was to use scanning laser vibrometry to determine the effects of load and toothpaste on the bristle vibration characteristics of four powered toothbrushes (Oral-B Sonic Complete; Oral-B Professional Care 8000 Series; Sonicare Elite and Ultrasonex). Toothbrushes were initially scanned, with the laser vibrometer, under unloaded conditions to provide baseline readings. Toothbrushes were then assessed under loaded conditions (1.00 N and 2.00 N), with and without toothpaste, to observe the effect on bristle motion. Application of 1.00 N load significantly reduced the displacement amplitudes of all powered toothbrushes (p<0.003) except for the Sonicare (p>0.497). With toothpaste, 1.00 N load caused a significant decrease in vibration displacement amplitude for all brushes (p<0.0001). The application of 2.00 N, with and without toothpaste, significantly reduced all toothbrushes vibration displacement amplitude (p<0.0001). Under all investigation conditions, the Oral-B 8000 had the largest vibration displacement amplitude of the toothbrushes tested. Load and toothpaste significantly affected the performance of powered toothbrushes. Understanding why these factors affect certain toothbrush designs more than others may lead to toothbrushes being designed with greater clinical efficacy.
To assess the vibration characteristics of oscillating objects with the scanning laser vibrometer... more To assess the vibration characteristics of oscillating objects with the scanning laser vibrometer (SLV). A laser is scanned over the surface of a vibrating target and the reflected, Doppler frequency shifted beam is used to determine the displacement amplitude and frequency of the vibration. This communication reports on a preliminary investigation to assess unloaded powered toothbrush oscillations, using Scanning Laser Vibrometry. Four powered toothbrushes were selected for this study including the Sonicare, Philips/Jordan Sensiflex HX2520, Braun 3D and Braun D8. Each toothbrush was clamped in position and 10 area scans of their heads were taken from the side orientation to determine the displacement amplitude and frequency of oscillation. The fundamental frequency of oscillation of each brush was determined: Sonicare: 262.5Hz; Philips: 62.5Hz; 3D: 75Hz and D8: 62.5Hz. The maximum displacement amplitude (half the peak-to-peak excursion) for each brush (at the tips of the longest br...
The aim of this study was to evaluate variations in power output of different Piezon-Master 400 (... more The aim of this study was to evaluate variations in power output of different Piezon-Master 400 (Electro Medical Systems, Nyon, Switzerland) ultrasonically driven generators and analytic handpieces at a range of power settings. A scanning laser vibrometer was used to measure the maximum vibration displacement amplitude of a KiS 2D tip. Ten repeat scans were made of the unloaded tip oscillation at six power settings. Data were acquired from four different generators and handpieces. Linear trend lines fitted to all tip data showed that none of the generator/handpiece combinations produced a linear increase in tip displacement amplitude with increasing power setting. A univariate analysis of variance (general linear model) showed that generator, handpiece, and power were all significant variables (p<0.0001). This study showed that there is significant variability in the power output between generators, and not all Analytic handpieces performed consistently when compared with each ot...
Passive ultrasonic irrigation may be used to improve bacterial reduction within the root canal. T... more Passive ultrasonic irrigation may be used to improve bacterial reduction within the root canal. The technique relies on a small file being driven to oscillate freely within the canal and activating an irrigant solution through biophysical forces such as microstreaming. There is limited information regarding a file's oscillation patterns when operated while surrounded by fluid as is the case within a canal root. Files of different sizes (#10 and #30, 27 mm and 31 mm) were connected to an ultrasound generator via a 120 degrees file holder. Files were immersed in a water bath, and a laser vibrometer set up with measurement lines superimposed over the files. The laser vibrometer was scanned over the oscillating files. Measurements were repeated 10 times for each file/power setting used. File mode shapes are comprised of a series of nodes/antinodes, with thinner, longer files producing more antinodes. The maximum vibration occurred at the free end of the file. Increasing generator po...
Ultrasonic dental scalers are clinically used to remove deposits from tooth surfaces. A metal pro... more Ultrasonic dental scalers are clinically used to remove deposits from tooth surfaces. A metal probe, oscillating at ultrasonic frequencies, is used to chip away deposits from the teeth. To reduce frictional heating, water flows over the operated probe in which a bi-product, cavitation, may be generated. The aim of this study is characterise probe oscillations using scanning laser vibrometry and
vibration. Study design: The vibration displacement amplitude of three designs of scaler insert, ... more vibration. Study design: The vibration displacement amplitude of three designs of scaler insert, including a Slimline tip, TFI-10 and TFI-3 (Dentsply, USA), were assessed unloaded and under 0.50 N and 1.00 N load and with water flow rates of 20 ml/min and 40 ml/min. Vibration analysis was performed us- ing a scanning laser vibrometer. Results: Increasing water flow rate from
The aim of this investigation was to determine if cavitation occurred around dental ultrasonic sc... more The aim of this investigation was to determine if cavitation occurred around dental ultrasonic scalers and to estimate the amount of cavitation occurring. Three styles of tip (3 x TFI-10, 3 x TFI-3, 3 x TFI-1) were used, in conjunction with a Cavitron SPS ultrasonic generator (Dentsply, USA), to insonate terephthalic acid solution. The hydroxyl radical, [*OH], concentration, produced due to cavitation from the scaler tips, was monitored by fluorescence spectroscopy. Cavitational activity was enhanced at higher power settings and at longer operating times. The tip dimensions and geometry as well as the generator power setting are both important factors that affect the production of cavitation.
ABSTRACT Magnetostrictive materials have been utilized for the production of resonant ultrasonic-... more ABSTRACT Magnetostrictive materials have been utilized for the production of resonant ultrasonic-frequency vibrations for a number of years. This effect has been utilised in laminated nickel-based ultrasonic dental scaler cleaning systems. Laser vibrometry measurements were undertaken that showed that a typical dental ultrasonic scaler resonated at 29 kHz due to dynamic magnetostriction of the insert&#39;s laminated nickel &#39;stack.&#39; This, in turn, excited insert probe vibrations that are used to remove dental calculus. 3D Femlab (TM) mechanical finite element models were created to explore the flexural vibration modes associated with the whole insert at the vibration frequency. These models indicated that it was possible to reproduce similar probe vibration mode-shapes to those seen via scanning laser vibrometry measurements. Also, the models indicate that vibrations, useful for dental scaling, can only be achieved if the coupled flexural and longitudinal resonant modes are stimulated at the same drive frequency.
Magnetostrictive materials have been utilized for the production of ultrasonic frequency vibratio... more Magnetostrictive materials have been utilized for the production of ultrasonic frequency vibrations for a number of years. This has particularly been the case in laminated nickel-based ultrasonic dental-scaler cleaning systems. In this study, a comparison has been ...
Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dent... more Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dental personnel and iatrogenic enamel cracking in teeth. However, methods for measuring dental handpiece vibrations have previously been limited and information about vibration characteristics is sparse. This preliminary study aimed to use a novel approach to assess the vibrations of unloaded high-speed handpieces in vitro. Maximum vibration displacement amplitudes of five air turbines and two speed-increasing handpieces were recorded whilst they were operated with and without a rotary cutting instrument (RCI) using a scanning laser vibrometer (SLV). RCI rotation speeds, calculated from frequency peaks, were consistent with expected values. ANOVA statistical analysis indicated significant differences in vibrations between handpiece models (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), although post hoc tests revealed that differences between most individual models were not significant (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.11). Operating handpieces with a RCI resulted in greater vibrations than with no RCI (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Points on the head of the handpiece showed greater vibration displacement amplitudes than points along the body (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Although no single measurement exceeded 4 microm for the handpieces in the current test setup (implying that these vibrations may be unlikely to cause adverse effects), this study has formed the basis for future work which will include handpiece vibration measurements whilst cutting under clinically representative loads.
The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with... more The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with the tooth surfaces. The aim of this study was to use scanning laser vibrometry to determine the effects of load and toothpaste on the bristle vibration characteristics of four powered toothbrushes (Oral-B Sonic Complete; Oral-B Professional Care 8000 Series; Sonicare Elite and Ultrasonex). Toothbrushes were initially scanned, with the laser vibrometer, under unloaded conditions to provide baseline readings. Toothbrushes were then assessed under loaded conditions (1.00 N and 2.00 N), with and without toothpaste, to observe the effect on bristle motion. Application of 1.00 N load significantly reduced the displacement amplitudes of all powered toothbrushes (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.003) except for the Sonicare (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.497). With toothpaste, 1.00 N load caused a significant decrease in vibration displacement amplitude for all brushes (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). The application of 2.00 N, with and without toothpaste, significantly reduced all toothbrushes vibration displacement amplitude (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). Under all investigation conditions, the Oral-B 8000 had the largest vibration displacement amplitude of the toothbrushes tested. Load and toothpaste significantly affected the performance of powered toothbrushes. Understanding why these factors affect certain toothbrush designs more than others may lead to toothbrushes being designed with greater clinical efficacy.
During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effe... more During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip displacement amplitude, using a scanning laser vibrometer. A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration displacement amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. For all tips, load and length were found to be significant variables (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). The scaler tips showed a fall in displacement amplitude with a reduction in tip length. However, all scaler tips showed variability in the amount oscillation that occurred. This was most pronounced with FSI-SLI-10S. This investigation demonstrated that tip wear could affect the performance of dental ultrasonic scaler inserts by reducing their vibration displacement amplitude. Clinicians should be aware of this variability, which may be significant enough to affect clinical procedures.
The aim of this investigation was to assess the effect of loading on ultrasonic scaler tip displa... more The aim of this investigation was to assess the effect of loading on ultrasonic scaler tip displacement amplitude, using a scanning laser vibrometer. Four generators were selected for this investigation including: Cavitron Select (Dentsply), Cavitron SPS (Dentsply), Piezon Master 400 (EMS) and Mini Piezon (EMS). The insert designs used with these generators included the TFI-10 and TFI-3 (with the Dentsply generators) and P-tip (with the EMS generators). The insert tips were contacted against tooth surfaces with loads of 0.25, 0.5 and 1.0 N. The scanning laser vibrometer was then used to scan the vibrating scalers at various generator power settings. The tips generally showed an increase in displacement amplitude with increasing power setting, although this increase was often nonlinear. Displacement amplitudes of like tips were generally found to be significantly different from each other at all loads. For individual inserts, loading caused a significant difference in tip response from the unloaded situation and also between loads. This investigation has demonstrated that there is a high variability associated with dental ultrasonic scaler inserts. Clinicians and researchers should be aware of this variability as it may affect both clinical procedures and future research.
During ultrasonic scaling procedures, contact of the scaler tip with the tooth surface will produ... more During ultrasonic scaling procedures, contact of the scaler tip with the tooth surface will produce frictional heating. The aim of this study was to assess this heat generation using an Agema 900 thermal imaging system. Both the Cavitron sustained performance system (SPS) with TFI-3 tip and the Mini Piezon with P-tip were tested. Handpieces were fixed with their sides facing the thermal camera and thermal image sequences or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;movies&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; created. Measurements were performed with tips under loads of 25, 50 and 100 g, at water flow rates of 10, 20 and 40 ml/min and low, medium and high generator power settings. A measurement point was superimposed on the resulting thermal images at the tip/tooth contact site and the temperature variation with time recorded. All combinations of instrumentation produced an increase in temperature. An increase in temperature was generally observed with increasing load (for given power/water), power setting (for given load/water) and a decrease in water flow rate (for given load/power). Heat generation is minimised by using low/medium power settings and light contact. Care must be taken to ensure adequate water is present at the site of instrumentation to prevent patient discomfort due to excessive heating.
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000
During a root canal treatment, an antimicrobial fluid is injected into the root canal to eradicat... more During a root canal treatment, an antimicrobial fluid is injected into the root canal to eradicate all bacteria from the root canal system. Agitation of the fluid using an ultrasonically vibrating miniature file results in a significant improvement in the cleaning efficacy over conventional syringe irrigation. Numerical analysis of the oscillation characteristics of the file, modeled as a tapered, driven rod, shows a sinusoidal wave pattern with an increase in amplitude and decrease in wavelength toward the free end of the file. Measurements of the file oscillation with a scanning laser vibrometer show good agreement with the numerical simulation. The numerical model of endodontic file oscillation has the potential for predicting the oscillation pattern and fracture likeliness of various file types and the acoustic streaming they induce during passive ultrasonic irrigation.
The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with... more The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with the tooth surfaces. The aim of this study was to use scanning laser vibrometry to determine the effects of load and toothpaste on the bristle vibration characteristics of four powered toothbrushes (Oral-B Sonic Complete; Oral-B Professional Care 8000 Series; Sonicare Elite and Ultrasonex). Toothbrushes were initially scanned, with the laser vibrometer, under unloaded conditions to provide baseline readings. Toothbrushes were then assessed under loaded conditions (1.00 N and 2.00 N), with and without toothpaste, to observe the effect on bristle motion. Application of 1.00 N load significantly reduced the displacement amplitudes of all powered toothbrushes (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.003) except for the Sonicare (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.497). With toothpaste, 1.00 N load caused a significant decrease in vibration displacement amplitude for all brushes (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). The application of 2.00 N, with and without toothpaste, significantly reduced all toothbrushes vibration displacement amplitude (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). Under all investigation conditions, the Oral-B 8000 had the largest vibration displacement amplitude of the toothbrushes tested. Load and toothpaste significantly affected the performance of powered toothbrushes. Understanding why these factors affect certain toothbrush designs more than others may lead to toothbrushes being designed with greater clinical efficacy.
To assess the vibration characteristics of oscillating objects with the scanning laser vibrometer... more To assess the vibration characteristics of oscillating objects with the scanning laser vibrometer (SLV). A laser is scanned over the surface of a vibrating target and the reflected, Doppler frequency shifted beam is used to determine the displacement amplitude and frequency of the vibration. This communication reports on a preliminary investigation to assess unloaded powered toothbrush oscillations, using Scanning Laser Vibrometry. Four powered toothbrushes were selected for this study including the Sonicare, Philips/Jordan Sensiflex HX2520, Braun 3D and Braun D8. Each toothbrush was clamped in position and 10 area scans of their heads were taken from the side orientation to determine the displacement amplitude and frequency of oscillation. The fundamental frequency of oscillation of each brush was determined: Sonicare: 262.5Hz; Philips: 62.5Hz; 3D: 75Hz and D8: 62.5Hz. The maximum displacement amplitude (half the peak-to-peak excursion) for each brush (at the tips of the longest br...
The aim of this study was to evaluate variations in power output of different Piezon-Master 400 (... more The aim of this study was to evaluate variations in power output of different Piezon-Master 400 (Electro Medical Systems, Nyon, Switzerland) ultrasonically driven generators and analytic handpieces at a range of power settings. A scanning laser vibrometer was used to measure the maximum vibration displacement amplitude of a KiS 2D tip. Ten repeat scans were made of the unloaded tip oscillation at six power settings. Data were acquired from four different generators and handpieces. Linear trend lines fitted to all tip data showed that none of the generator/handpiece combinations produced a linear increase in tip displacement amplitude with increasing power setting. A univariate analysis of variance (general linear model) showed that generator, handpiece, and power were all significant variables (p<0.0001). This study showed that there is significant variability in the power output between generators, and not all Analytic handpieces performed consistently when compared with each ot...
Passive ultrasonic irrigation may be used to improve bacterial reduction within the root canal. T... more Passive ultrasonic irrigation may be used to improve bacterial reduction within the root canal. The technique relies on a small file being driven to oscillate freely within the canal and activating an irrigant solution through biophysical forces such as microstreaming. There is limited information regarding a file's oscillation patterns when operated while surrounded by fluid as is the case within a canal root. Files of different sizes (#10 and #30, 27 mm and 31 mm) were connected to an ultrasound generator via a 120 degrees file holder. Files were immersed in a water bath, and a laser vibrometer set up with measurement lines superimposed over the files. The laser vibrometer was scanned over the oscillating files. Measurements were repeated 10 times for each file/power setting used. File mode shapes are comprised of a series of nodes/antinodes, with thinner, longer files producing more antinodes. The maximum vibration occurred at the free end of the file. Increasing generator po...
Ultrasonic dental scalers are clinically used to remove deposits from tooth surfaces. A metal pro... more Ultrasonic dental scalers are clinically used to remove deposits from tooth surfaces. A metal probe, oscillating at ultrasonic frequencies, is used to chip away deposits from the teeth. To reduce frictional heating, water flows over the operated probe in which a bi-product, cavitation, may be generated. The aim of this study is characterise probe oscillations using scanning laser vibrometry and
vibration. Study design: The vibration displacement amplitude of three designs of scaler insert, ... more vibration. Study design: The vibration displacement amplitude of three designs of scaler insert, including a Slimline tip, TFI-10 and TFI-3 (Dentsply, USA), were assessed unloaded and under 0.50 N and 1.00 N load and with water flow rates of 20 ml/min and 40 ml/min. Vibration analysis was performed us- ing a scanning laser vibrometer. Results: Increasing water flow rate from
The aim of this investigation was to determine if cavitation occurred around dental ultrasonic sc... more The aim of this investigation was to determine if cavitation occurred around dental ultrasonic scalers and to estimate the amount of cavitation occurring. Three styles of tip (3 x TFI-10, 3 x TFI-3, 3 x TFI-1) were used, in conjunction with a Cavitron SPS ultrasonic generator (Dentsply, USA), to insonate terephthalic acid solution. The hydroxyl radical, [*OH], concentration, produced due to cavitation from the scaler tips, was monitored by fluorescence spectroscopy. Cavitational activity was enhanced at higher power settings and at longer operating times. The tip dimensions and geometry as well as the generator power setting are both important factors that affect the production of cavitation.
ABSTRACT Magnetostrictive materials have been utilized for the production of resonant ultrasonic-... more ABSTRACT Magnetostrictive materials have been utilized for the production of resonant ultrasonic-frequency vibrations for a number of years. This effect has been utilised in laminated nickel-based ultrasonic dental scaler cleaning systems. Laser vibrometry measurements were undertaken that showed that a typical dental ultrasonic scaler resonated at 29 kHz due to dynamic magnetostriction of the insert&#39;s laminated nickel &#39;stack.&#39; This, in turn, excited insert probe vibrations that are used to remove dental calculus. 3D Femlab (TM) mechanical finite element models were created to explore the flexural vibration modes associated with the whole insert at the vibration frequency. These models indicated that it was possible to reproduce similar probe vibration mode-shapes to those seen via scanning laser vibrometry measurements. Also, the models indicate that vibrations, useful for dental scaling, can only be achieved if the coupled flexural and longitudinal resonant modes are stimulated at the same drive frequency.
Magnetostrictive materials have been utilized for the production of ultrasonic frequency vibratio... more Magnetostrictive materials have been utilized for the production of ultrasonic frequency vibrations for a number of years. This has particularly been the case in laminated nickel-based ultrasonic dental-scaler cleaning systems. In this study, a comparison has been ...
Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dent... more Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dental personnel and iatrogenic enamel cracking in teeth. However, methods for measuring dental handpiece vibrations have previously been limited and information about vibration characteristics is sparse. This preliminary study aimed to use a novel approach to assess the vibrations of unloaded high-speed handpieces in vitro. Maximum vibration displacement amplitudes of five air turbines and two speed-increasing handpieces were recorded whilst they were operated with and without a rotary cutting instrument (RCI) using a scanning laser vibrometer (SLV). RCI rotation speeds, calculated from frequency peaks, were consistent with expected values. ANOVA statistical analysis indicated significant differences in vibrations between handpiece models (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), although post hoc tests revealed that differences between most individual models were not significant (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.11). Operating handpieces with a RCI resulted in greater vibrations than with no RCI (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Points on the head of the handpiece showed greater vibration displacement amplitudes than points along the body (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Although no single measurement exceeded 4 microm for the handpieces in the current test setup (implying that these vibrations may be unlikely to cause adverse effects), this study has formed the basis for future work which will include handpiece vibration measurements whilst cutting under clinically representative loads.
The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with... more The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with the tooth surfaces. The aim of this study was to use scanning laser vibrometry to determine the effects of load and toothpaste on the bristle vibration characteristics of four powered toothbrushes (Oral-B Sonic Complete; Oral-B Professional Care 8000 Series; Sonicare Elite and Ultrasonex). Toothbrushes were initially scanned, with the laser vibrometer, under unloaded conditions to provide baseline readings. Toothbrushes were then assessed under loaded conditions (1.00 N and 2.00 N), with and without toothpaste, to observe the effect on bristle motion. Application of 1.00 N load significantly reduced the displacement amplitudes of all powered toothbrushes (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.003) except for the Sonicare (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.497). With toothpaste, 1.00 N load caused a significant decrease in vibration displacement amplitude for all brushes (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). The application of 2.00 N, with and without toothpaste, significantly reduced all toothbrushes vibration displacement amplitude (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). Under all investigation conditions, the Oral-B 8000 had the largest vibration displacement amplitude of the toothbrushes tested. Load and toothpaste significantly affected the performance of powered toothbrushes. Understanding why these factors affect certain toothbrush designs more than others may lead to toothbrushes being designed with greater clinical efficacy.
During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effe... more During clinical usage, scaler tips may become worn and reduced in length. It is unknown what effect wear has on the magnitude of scaler tip vibrations when they are utilized under typical clinical loads. The aim of this investigation was to assess the effect of simulated wear on ultrasonic scaler tip displacement amplitude, using a scanning laser vibrometer. A Cavitron SPS (Dentsply) ultrasonic generator and three scaler insert designs (FSI-100, FSI-1000 and FSI-SLI-10S) were selected for the investigation. Tip vibration displacement amplitude was assessed unloaded and then contacting against tooth surfaces with loads of 0.5 and 1.0 N. Tips were then ground down by 1 mm and then 2 mm and scans were repeated. For all tips, load and length were found to be significant variables (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). The scaler tips showed a fall in displacement amplitude with a reduction in tip length. However, all scaler tips showed variability in the amount oscillation that occurred. This was most pronounced with FSI-SLI-10S. This investigation demonstrated that tip wear could affect the performance of dental ultrasonic scaler inserts by reducing their vibration displacement amplitude. Clinicians should be aware of this variability, which may be significant enough to affect clinical procedures.
The aim of this investigation was to assess the effect of loading on ultrasonic scaler tip displa... more The aim of this investigation was to assess the effect of loading on ultrasonic scaler tip displacement amplitude, using a scanning laser vibrometer. Four generators were selected for this investigation including: Cavitron Select (Dentsply), Cavitron SPS (Dentsply), Piezon Master 400 (EMS) and Mini Piezon (EMS). The insert designs used with these generators included the TFI-10 and TFI-3 (with the Dentsply generators) and P-tip (with the EMS generators). The insert tips were contacted against tooth surfaces with loads of 0.25, 0.5 and 1.0 N. The scanning laser vibrometer was then used to scan the vibrating scalers at various generator power settings. The tips generally showed an increase in displacement amplitude with increasing power setting, although this increase was often nonlinear. Displacement amplitudes of like tips were generally found to be significantly different from each other at all loads. For individual inserts, loading caused a significant difference in tip response from the unloaded situation and also between loads. This investigation has demonstrated that there is a high variability associated with dental ultrasonic scaler inserts. Clinicians and researchers should be aware of this variability as it may affect both clinical procedures and future research.
During ultrasonic scaling procedures, contact of the scaler tip with the tooth surface will produ... more During ultrasonic scaling procedures, contact of the scaler tip with the tooth surface will produce frictional heating. The aim of this study was to assess this heat generation using an Agema 900 thermal imaging system. Both the Cavitron sustained performance system (SPS) with TFI-3 tip and the Mini Piezon with P-tip were tested. Handpieces were fixed with their sides facing the thermal camera and thermal image sequences or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;movies&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; created. Measurements were performed with tips under loads of 25, 50 and 100 g, at water flow rates of 10, 20 and 40 ml/min and low, medium and high generator power settings. A measurement point was superimposed on the resulting thermal images at the tip/tooth contact site and the temperature variation with time recorded. All combinations of instrumentation produced an increase in temperature. An increase in temperature was generally observed with increasing load (for given power/water), power setting (for given load/water) and a decrease in water flow rate (for given load/power). Heat generation is minimised by using low/medium power settings and light contact. Care must be taken to ensure adequate water is present at the site of instrumentation to prevent patient discomfort due to excessive heating.
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000
During a root canal treatment, an antimicrobial fluid is injected into the root canal to eradicat... more During a root canal treatment, an antimicrobial fluid is injected into the root canal to eradicate all bacteria from the root canal system. Agitation of the fluid using an ultrasonically vibrating miniature file results in a significant improvement in the cleaning efficacy over conventional syringe irrigation. Numerical analysis of the oscillation characteristics of the file, modeled as a tapered, driven rod, shows a sinusoidal wave pattern with an increase in amplitude and decrease in wavelength toward the free end of the file. Measurements of the file oscillation with a scanning laser vibrometer show good agreement with the numerical simulation. The numerical model of endodontic file oscillation has the potential for predicting the oscillation pattern and fracture likeliness of various file types and the acoustic streaming they induce during passive ultrasonic irrigation.
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