Dental Scaler Research Articles

Eye Movements of Dental Hygienist Students When Choosing a Dental Scaler : In Case of the Curette Type for a Specific Region of the Tooth

Eye Movements of Dental Hygienist Students When Choosing a Dental Scaler : In Case of the Curette Type for a Specific Region of the Tooth

Cavitation occurrence around ultrasonic dental scalers

Ultrasonic scalers are used in dentistry to remove calculus and other contaminants from teeth. One mechanism which may assist in the cleaning is cavitation generated in cooling water around the scaler. The vibratory motion of three designs of scaler tip in a water bath has been characterised by laser vibrometry, and compared with the spatial distribution of cavitation around the scaler tips observed using sonochemiluminescence from a luminol solution. The type of cavitation was confirmed by acoustic emission analysed by a ‘Cavimeter’ supplied by NPL. A node/antinode vibration pattern was observed, with the maximum displacement of each type of tip occurring at the free end. High levels of cavitation activity occurred in areas surrounding the vibration antinodes, although minimal levels were observed at the free end of the tip. There was also good correlation between vibration amplitude and sonochemiluminescence at other points along the scaler tip. ‘Cavimeter’ analysis correlated well with luminol observations, suggesting the presence of primarily transient cavitation.

Difference in physiological responses to sound stimulation in subjects with and without fear of dental treatments

The effects of sound generated by an ultrasonic dental scaler and a dental turbine on heart rate, systolic and diastolic blood pressure, and hemodynamic changes in the frontal cortex were measured and compared with those of pure tone stimulation in 17 young volunteers. Near-infrared spectroscopy and the Finapres technique were used to measure hemodynamic and cardiovascular responses, respectively. The dental sound changed the various physiological parameters. To determine if this change was related to participants' previous experiences with dental treatment, participants were divided into two groups: those who had a previous unpleasant experience with dental treatment and those who had not. Participants with previous unpleasant dental experiences showed a significant decrease in cerebral blood flow. Participants who had not had an unpleasant dental experience did not show significant changes in cerebral blood flow. Thus, although sounds associated with dental treatment may reduce cerebral blood flow, this effect may depend on the dental experiences of the patient. It is recommended that dentists treat patients gently and with empathy to promote a friendly image of dentistry.

A comparison of and the compensation for magnetostrictive core inductances in magnetic transducer systems

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 made between the impedances of a number of magnetostrictive stacks of 50 mm×4 mm×∼0.3 mm strips at frequencies in the range of 10–50 kHz in a coil used for the excitation of a stack in a dental-scaler system. The magnetostrictive stacks tested comprised of potential replacement materials for standard nickel ones. The study showed that it was possible to compensate for the inductive ‘imaginary’ components of the impedance through the use of a tuned, series capacitance so that only the ‘real’ resistive component of the impedance remained. This reduced the electrical losses associated with the excitation of the magnetostrictive stacks as a result of the frequency-dependent inductance of the coil system. Consequently, the maximum power transfer from an amplifier to the transducer was increased. Also, the investigation showed how the ‘real’ component of impedance of the different stacks varied with frequency. In a tuned resonant electrical circuit, the resistive component of the impedance, if considered as a loss, would be the lowest that could be achieved with such a magnetic circuit. Consequently, the losses associated with resonant magnetostrictive devices, like dental scalers, can be reduced.

Evaluation of Sharpness of Dental Scalers Using Optical Reflection of Blades Rotated in Two Directions

Dentists and dental hygienists remove dental calculus using a cutting tool called dental scaler. The evaluation of sharpness of dental scalers requires skill which depends on sensory examination. The aim of this research is to evaluate the sharpness of scalers objectively by estimating optical reflection images of blades rotated in two directions. For taking photos of blades at various angles using CCD camera, the scaler to be inspected was fixed on a turn table driven by a stepping motor. In this research, the angle of a scaler fixture on the turn table was also changed by a RC servo motor. As a result, the optical reflection patterns of the cutting edge could be obtained more precisely than before. Next, an image processing method was examined for calculating the area and the length of optical reflection patterns of the cutting edge from the photos obtained from various angles. And the relation between these values and the sensory evaluated values was examined using multiple regression analysis. As a result, it was confirmed that this method can evaluate the sharpness of scalers objectively and precisely. And it was also confirmed that the angle of the scaler fixture is also an important factor for this evaluation method as well as the angle of the scaler.

스테인레스계열(17-4PH, 316L, 440C) 분말을 이용한 Dental Scaler Tip 분말사출금형 개발

Powder injection molding(PIM) is widely used for many parts in the field of automotives, electronics and medical industries, due to the capability of net shaping for complex 3-D geometry. Powder injection mold design for the dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip which has complex geometry. Both product design and mold design for dental scaler tip were presented. A PIM feedstock was made of stainless series(17-4PH, 316L, 440C) powder and a wax based binder. The 'rapid mold' concept was applied to manufacture the various forms and materials of dental scaler tip including vibration characteristics.

Computer Aided Engineering Design of Powder Injection Molding Process for a Dental Scaler Tip Mold Design

Powder Injection Molding (PIM) has recently been recognized as an advanced manufacturing technology for low-cost mass production of metal or ceramic parts of complicated geometry. With this regards, design technology of dental scaler tip PIM mold, which has complex shape and a slim core pin of 0.6 mm diameter, with the help of computer-aided analysis for powder injection molding process was developed. Computer-aided analysis for dental scaler tip mold was implemented by finite element method with non-Newtonian fluid, modified Cross model viscosity, PvT data of powder/binder mixture. The core deflection analysis of dental scaler tip PIM mold during PIM filling process was also investigated. Compter-aided analysis results, such as filling pattern, weldline formation, and air vent position prediction were investigated and eventually showed good agreements with experimental results.

415 共振周波数追従機能を利用した超音波スケーラによる歯科診断

415 共振周波数追従機能を利用した超音波スケーラによる歯科診断

Development of Dental Scaler Tip Mold with Powder Injection Molding Process

With the capability of net shaping for complex 3D geometry, powder injection molding (PIM) is widely used for automotive parts, electronics and medical industry. In this study, an ultrasonic dental scaler tip produced by machining process was redesigned for the PIM process. An injection mold was designed and machined to produce the dental scaler tip by the PIM process. The mold design was aided by CAE analysis. A PIM feedstock was made of SUS316L powder and a wax based binder. The filling balance in the mold was checked by a short shot test with LDPE and the PIM feedstock. Production capability of the PIM process for the dental scaler tip was examined with the mold. Although there were minor problems such as a discoloration around the gate and a flashing at the air vent, the PIM process turned out to be an excellent substitute for machining process to manufacture the ultrasonic dental scaler tip.

Application of Ultrasonic Dental Scaler for Diagnosis

Ultrasonic dental scaler is an instrument to remove dental calculi using ultrasonic vibration of a transducer. The conventional transducer has a hose to provide water to scaling point. The hose causes attenuation of the ultrasonic vibration. This paper describes a new transducer design to avoid the attenuation. Design decision by comparison of two types of transducer designs is reported. Additionally, the ultrasonic transducer is used in resonance condition. The resonance frequency, however, is shifted according to value of input voltage to the transducer and condition of contact with tooth or gum. This paper presents a resonance frequency tracing system to solve the frequency shift. Step responses are specified as evaluation of the system. Application of the system to diagnosis is also discussed. Experiments on measurement of object properties are reported. The results indicate possibility that dental health can be investigated by observing the frequency shift during the scaler operation.

Ultrasonically set glass polyalkenoate cements for orthodontic applications

There is an accepted clinical requirement for a luting cement that can be command set upon satisfactory placement of an orthodontic appliance onto dentition. This work evaluates the suitability of ultrasound, imparted from a dental scaler, as a potential mechanism for achieving this. The net setting times and subsequent compressive strengths of a range of commercial and experimental glass polyalkenoate cements (GPCs) were evaluated, using modified ISO 9917 methods, when set both chemically and by ultrasound. The ultrasound was applied to the GPC through an orthodontic brace. It was possible to command set GPCs by the application of five to ten seconds of ultrasound; the exact time required being dependent upon the composition of the GPC in question. The compressive strengths of these cements can be improved by around 90% with the command set when the optimum PAA molecular weight and tartaric acid content is employed.

Control of tip oscillation in magnetostrictive dental scalers

Ultrasonic dental scalers are electronically powered dental cleaning tools which are commonly used by clinicians for dental cleaning. They were developed in the mid 1950s [S.C. Trenter, A.D. Walmsley, G. Landini, J.M. Shippen, Assessment of the ultrasonic dental scaler insert, Med. Eng. Phy. 24 (2002) 139–144]. Ultrasonic scalers are being widely used with few studies on the correct methods and techniques that should be used to obtain their maximum efficiency. Different types of inserts/tips do not show clearly which particular designs are best suited to the task of removing dental calculus to combat periodontal disease. The aim of this study is to begin preliminary investigation on whether the performance of these clinical instruments may be improved if the displacement waveform of the scaler tip could be controlled.

Development of Ultrasonic Dental Scaler with A Diagnosis Function

An ultrasonic dental scaler is an equipment to remove dental calculi from teeth. A conventional scaler consists of handpiece with a Langevin type ultrasonic transducer and a driver circuit to vibrate at resonance frequency. The transducer has a horn to enhance vibration and a tip to scale the calculi. On the back of the transducer, a rubber hose is connected to supply water to the scaling points. Such a transducer has two problems. One is vibration damping due to the water hose. The other is resonance frequency shift according to contact load on the tip. Two types of transducer are fabricated to compare influence of the hose connecting method. Measuring electric Q factor with water flowing, side connection seems to decrease the damping rather than back connection. A new transducer is designed based on the comparison result. To trace the frequency shift, we develop a resonance trace system. Arranging operating frequency based on detected current phase, the system can trace mechanical resonance with time delay of 17 ms. We also propose teeth diagnosis using the resonance trace system. Observing the resonance frequency shift when the tip contacts a material, stiffness of the material can be estimated. The shift comparison result between a damaged tooth and a fine tooth shows possibility of dental caries diagnosis.

The effect of multilayer filtered arc coatings on mechanical properties, corrosion resistance and performance of periodontal dental instruments

A large-area filtered arc deposition (LAFAD) process was used to deposit various multi-layer cermet coatings on dental scalers made of martensitic stainless steel. A custom mechanical stroking device was used to include features capable of simulating the load and motion of dental scalers against enamel or dentin tooth surfaces in an aqueous environment. Subjecting the coated instruments to vibratory tumbling in a vat containing cellulose filler and an abrasive tested the abrasion resistance of the coating. The working edge wear was then investigated by means of optical and electron microscopy as well as by metallurgical cross-section profile analysis. Coating adhesion was determined by measuring delamination during Rockwell testing. Corrosion resistance of dental instruments with multi-layer coatings was studied by subjecting the instruments to repeated conventional autoclave sterilization procedures. Comparison of the laboratory tests with the field testing results in dental clinical practice is presented. The mass production yield of high-quality scalers with LAFAD coatings is discussed.

치과용 스케일러 금형의 분말사출성형 CAE 해석설계

Powder Injection Molding(PIM) has recently been recognized as an advanced manufacturing technology for low-cost mass production of metal or ceramic parts of complicated geometry With this regards, design technology of dental scaler tip PIM mold, which has complex shape and small core pin (diameter=0.6mm), with the help of computer-aided analysis of powder injection molding process was developed. Computer-aided analysis for dental scaler tip mold was implemented by finite element method with non-Newtonian fluid, modified Cross model viscosity, PvT data of powder/binder mixture. Compter-aided analysis results, such as filling pattern, weldline formation, air vent position prediction were compared with experimental result, and eventually have been shown good agreement. The core pin (diameter=0.6mm) deflection analysis of dental scaler tip PIM mold during PIM filling process was also investigated before mold fabrication.

Evaluation of Sharpness of Dental Scalers Using Optical Reflection

Dentists and dental hygienists remove dental calculus using a cutting tool called dental scaler. The evaluation of sharpness of dental scalers requires skill which depends on sensory examination. The aim of this research is to evaluate the sharpness of scalers objectively. First, an apparatus for taking images of scalers was developed by taking into account the evaluation method of observing the cutting edge reflection used by experts. The scaler to be inspected was fixed on a turn table driven by a stepping motor. The angle of the scaler was changed by the stepping motor and images of the cutting edge of the scaler were taken at various angles by a CCD camera. Next, the area and the length of optical reflection pattern of the cutting edge were measured using some images taken from different angles. And the relation between these values and the sensory evaluation was examined. As a result, the implications between them were found out. And, it was confirmed that this method can evaluate the sharpness of scalers objectively.

621 診断機能を備えた歯科用超音波スケーラの開発

Ultrasonic dental scaler is an instrument to remove dental calculus using ultrasonic vibration of a transducer. The transducer is used in resonant condition. However, its resonance frequency changes with value of input voltage to the transducer and condition of contact with tooth or gum. To solve the problem, we produced a system that traces change of resonance frequency and generates driving signal with that frequency. In addition, a novel diagnosis of dental abnormality using the fabricated system was proposed and discussed.

Ultrasonic dental scaler: associated hazards.

The ultrasonic dental scaler is a valuable tool in the prevention of periodontal disease; however, this equipment has a number of hazards with which it is associated. These include heating of the tooth during scaling, vibrational hazards causing cell disruption, possible platelet damage by cavitation, associated electromagnetic fields that can interrupt pacemakers, auditory damage to patient and clinician and the release of aerosols containing dangerous bacteria. To collate the research reported on the various hazards associated with the ultrasonic dental scaler and discuss possible future research areas. The scientific literature was searched using Web of Science, EMBASE and Medline, and the results of these were then hand-searched to eliminate nonrelevant papers. This review outlines some of the research conducted into these areas of associated hazard in order to assess their significance in the clinical situation, and discusses ideas for future research. Suggestions of recommendations are given, which have been previously investigated for their aid in reducing possible hazards, to ensure the safe working of ultrasonic scalers in the dental practice.

Assessment of the ultrasonic dental scaler insert

The ultrasonic dental scaler is an invaluable tool in the fight against dental calculus and periodontal disease. The purpose of this study was to assess the natural frequency of the straight internal ultrasonic scaler insert 30K™ FSI®-SLI™-10S (Dentsply International, York, USA) and to measure the displacement observed at the tip when operated under different generator settings. Two approaches were used: finite element analysis and scanning laser vibrometry. The Finite Element Analysis method was employed to calculate the expected modes of vibration of the insert. Scanning laser vibrometry was used to measure displacements of the tip during operation. It was found the insert had two modes of vibration around the operating frequency of 30kHz; these modes were first order bending in two orthogonal planes.

Evaluation of Sharpness for Dental Scalers

As a plaque control method, the removal of calculus deposited on the teeth surface is indispensable in the prevention and treatment of periodontal disease. The hand scalar, which is used for removing calculus, must be sharpened just after used it in order to keep it original sharpness. But the qualitative checking method is not established yet. The authors have designed and made an apparatus as an experiment for the evaluation of a model scalar' s sharpeness. The model scalar is straight and large as compared with a real hand scalar. This report deals with the apparatus and it's chracteristics.The ranges of rake angles of the scalers covers from-20deg to 0 deg, and speeds of the bed on which the model teeth(test piece)is fixed from0.5mm/ sec to3.0mm/ sec. Vertical pushing force of the scalar to the test piece and cutting resistance are measured by the use of strain gages. Metals such as steel and aluminum, glass are used as the material for the model teeth.Plastics cement which were dripped on the surface of model teeth are used as the material of calculus. After the cement became solid and set up the parameters such as speed of the bed and pushing force to the scaler, it is ready to scrub away the cement. In the case of the dripped cement were removed and impulsive force data were observed, then it may conclude that the scaler is sharp.