Brush Movement Research Articles

Cervical wear pathobiology by robot-simulated 3-year toothbrushing – New methodological approach

ObjectivesAn ex-vivo study was aimed at (i) programming clinically validated robot three-year random toothbrushing, (ii) evaluating cervical macro- and microwear patterns on all tooth groups of different functional age, (iii) documenting and codificating wear related morphological features at the cemento-enamel junction in young teeth and on roots in older teeth. DesignFollowing ethical approval random toothbrushing (44 strokes per tooth horizontally, rotating, vertically; 2x/d) with manual toothbrushes and low-abrasive dentifrice was performed in an artificial oral cavity with brushing-force 3.5 N on 14 extracted human teeth. Morphological features were examined by SEM at baseline and after simulated 3 years using the replication technique. 3D-SEM analyses were carried out with a four-quadrant back scattered electron detector. Wilcoxon-Mann-Whitney-test was used for statistical analyses. Results3-year random toothbrushing with horizontal, rotating and vertical brushing movements revealed morphological features classified as four enamel patterns, one dentin pattern and three cervical patterns. Negative impacts were enamel, cementum and dentin loss. Positive impact on oral health was removing dental calculus and straightening cervical traumatic and iatrogenic damages. The volume loss varied from x̅=34.25nl to x̅=87.75nl. Wear extended apically from 100 to 1500 micrometres. ConclusionRobot simulated toothbrushing in an artificial oral cavity, with subsequent SEM and 3D-SEM assessment, elucidated both negative and oral health-contributing micromorphology patterns of cervical wear after simulated 3-year random toothbrushing. Cervical macro- and microwear of cementum revealed, for the first time, what we describe as overhanging enamel peninsulas and enamel islands on roots in young teeth, but no enamel islands on roots from older teeth after root cementum loss. In contrast, many older teeth exhibited enamel peninsulas.

The Effect of Educational Games on Tooth Brushing Skills in Preschool Children

Educational regarding proper tooth brushing procedures needs to be carried out since preschool, because this is a golden time to build a habit. However, the proportion of correct brushing behavior based on RISKESDAS 2019 is only 2.8%. To overcome this behavior, it is necessary to provide treatment that attracts children's attention, such as providing educational games. The educational game that designed by researchers is about Tooth brushing Simulation using the Doctor Toys Set Educational Game Tool and video for how to play. The purpose of this study was to determine the effect of educational games to improve toothbrushing skills in Atikan Kindergarten, Bandung City. This research method uses a pre-experimental one group pre-test – post-test design which was carried out in April 2022 with a total sampling of 20 children. Toothbrushing skills were observed 2 times, before treatment (pre-test) and after treatment with educational games (post-test). Data analysis used paired-T test. The average score of the correct brushing movement before and after doing the Educational Game on Simulation of Brushing Teeth was 6.65 and 11.85 and there was a significant difference based on the mean score (p<0.05). The conclusion is that an Educational Game about Simulation of Brushing Teeth with Doctor Toys Set and a video of how to play the tool can be used to improve tooth brushing skills in pre-school children.

Impact of manual toothbrush design on plaque removal efficacy

BackgroundEffective dental plaque removal is essential for oral health. Different toothbrush parameters including head-size, filament-diameter and interdent-height and different brushing movements like horizontal, rotating and vertical may affect plaque removal efficacy. The purpose of the study was to examine plaque removal efficacy of different design parameters of manual toothbrushes.MethodsEight manual toothbrushes were tested using a validated robot test to examine efficacy of toothbrush on replicated human teeth. Characteristics tested were: (i) head-size, (ii) filament-diameter, (iii) cutting-height, (iv) hardness, (v) interdental-height. Each test ran five times in horizontal, rotating, vertical movements. Simulated Plaque removal was evaluated using automated plaque planimetry: 30 fields/tooth, 13 areas representing buccal, lingual, proximal tooth sites. The Kolmogorov-Smirnov-test was applied to test tooth surface variables for normal distribution of plaque removal values. Parameters were analysed by independent two-sample t-test to assess mean differences. Where null hypothesis of normality was rejected, the Wilcoxon-Mann-Whitney-U-test was used.ResultsPlaque removal was significantly better with toothbrush having smaller head-size (compact vs. full-size); smaller filament-diameter (0.12 mm vs. 0.15 mm); larger cutting-height (12 mm vs. 9 mm); softer filaments (0.15 or 0.18 mm vs. 0.23 mm) and greater interdent-height difference (8.5/11 mm vs. 10/11 mm).ConclusionsManual brushes allowing filaments free to flex with longer, softer and/or having a difference in filament length overall removed significantly more simulated plaque as compared to more standard flat trim, stiff brushes with shorter, harder bristles and a larger head size. While limited by the in vitro nature of the study design, this indicates that the advances in toothbrush design can further enhance plaque removal.

Impact of different brushing/abrasion protocols on erosive tooth wear for in vitro studies

ObjectiveTo investigate the influence of different toothbrushing (with dentifrice) protocols on the progression of erosive tooth wear for in vitro studies. DesignBovine enamel specimens were randomly distributed into 12 experimental groups (n = 10), according to the study factors: (1) brushing movement (horizontal or circular); (2) slurry diluent (artificial saliva or distilled water); (3) toothpaste dilution ratio (1:2, 1:3 or 1:4). A 5-day erosion-abrasion cycling model was performed, each consisting of 4 erosive challenges (0.3 % citric acid, pH=2.6) followed by 60 min exposure to artificial saliva. Brushing with fluoride toothpaste (15 s, 1400 ppm F-, AmF) was carried out 2x/day. Enamel surface loss (SL) was determined by optical profilometry. Data were statistically analyzed with three-way ANOVA and Tukey tests (α = 0.05). ResultsSL was lower for the horizontal movement than for the circular (p = 0.044). There were no significant differences among the dilution ratios for artificial saliva. For distilled water, the more concentrated slurry (1:2) presented greater surface loss than the less concentrated slurries (1:3 and 1:4, p = 0.049 and p = 0.014, respectively). Dilutions with artificial saliva at ratios 1:3 and 1:4 presented higher surface loss than with distilled water (p = 0.008 and p < 0.001, respectively); however, for 1:2 ratio, there were no significant differences between the diluents. ConclusionsThe in vitro progression of enamel SL was influenced by the brushing movement, as well as the combination of the dilution ratio and the diluent of the toothpaste slurry, and therefore, all these factors must be considered when comparing results from different studies.

Physicochemically Constructed Unidirectional Aluminum Bismuth Gallium Zinc Oxide Film for Enhanced Nematic Liquid Crystal System Using a Brush‐Coating Method

We propose a convenient brush coating method for liquid crystal (LC) alignment. This method enables film deposition and an alignment layer treatment process simultaneously. Aluminum bismuth gallium zinc oxide (AlBiGaZnO) is used as the alignment layer. After the curing process, a unidirectional AlBiGaZnO film is formed; its surface morphology and chemical composition were verified using scanning electron microscopy and X-ray photoelectron spectroscopy. This oriented structure of the surface was produced by shear-stress which originated from brush movement. That structure induced a surface anisotropic characteristic and resulted in a uniform LC alignment. The uniform and homogeneous LC alignment state on the film was confirmed using polarized optical microscopy and pre-tilt angle analysis. The brush coated AlBiGaZnO film exhibited excellent thermal budget for advanced LC system. The film exhibited enhanced electro-optical performance with a low operating voltage. These results demonstrate the potential of LC alignment technology via the brush coating method.

Implementing Healthy Life and Self and Environmental Clean on Orphans in Islahul Hidayat Orphanage

Clean and healthy living behavior (PHBS) is a step that must be taken to achieve optimal health degrees for everyone including in the foundation. The emergence of various diseases that often affect children aged (5-11 years) is generally related to Clean and Healthy Living Behavior (PHBS). Some children exhibit unhealthy behaviors such as preferring to consume unhealthy foods that are high in fat, sugar, salt, low in fiber, increase the risk of hypertension, diabetes mellitus, obesity, and so on. In addition, it was also found that children who did not brush their teeth when after eating and before going to bed so that their teeth cavities. This condition must be anticipated immediately by improving a healthy lifestyle through PHBS. Based on surveys and interviews conducted with children at Rumah Yatim and Duafa Yayasan Islahul Hayat, Pondok Petir said it did not know how to brush teeth properly and correctly. This community service (PKM) aims to improve the knowledge and degree of health of children in Rumah Yatim and Duafa Yayasan Islahul Hayat, Pondok Petir by counseling to maintain dental health and how to brush teeth properly and mass brushing activities. This PKM activity was carried out in accordance with the planning and lasted for one day. PHBS Dental Health Counseling and The Right Teeth brushing Movement is effective to realize health education to instill PHBS values so that it has the potential as a change agent to promote PHBS both in school, family, and community environments.

What characterizes effective tooth brushing of daily users of powered versus manual toothbrushes?

BackgroundRecent data show comparable deficits in oral cleanliness after tooth brushing in habitual users of powered toothbrushes (PT) and manual toothbrushes (MT). The present analysis explores the origin of these deficits by relating aspects of the observed tooth brushing behaviour to plaque after tooth brushing.MethodsUsers of rotating-oscillating PT (N = 48) and of MT (N = 52) brushed their teeth the best they could while being filmed. Video analyses assessed brushing time, number of sextants brushed sufficiently long (7.5 s per surface; NSBSL), brushing of outer surfaces with closed jaws, and brushing movements. Correlation analyses examined the relationship between these parameters and plaque after brushing (Marginal Plaque Index (MPI); Turesky modification of Quigley Hein Index (TQHI)) and gingivitis (Papillary Bleeding Index (PBI)).ResultsIn PT users, correlations between behaviour and MPI-scores were significant for the NSBSL (outer surfaces: rho = − 0.249; inner surfaces: rho = − 0.510) and brushing duration (outer surfaces: rho = − 0.399; inner surfaces: rho = − 0.509). In MT users, vertical movements on the outer surfaces were positively related to MPI (rho = 0.299). In contrast, circular movements correlated negatively with MPI in those who brushed all outer sextants sufficiently long (n = 47: rho = − 0.294). In both groups, PBI-scores on the inner surfaces were negatively correlated to NSBSL and brushing duration (rho = − 0.327 − rho = − 0.246).ConclusionNSBSL and brushing duration appear to play an important role for brushing effectiveness and gingival health in PT and MT users. Whether PT users apply brushing movements or not apparently does not affect the result. In MT users, circular movements seem to be more efficient than vertical movements on the outer surfaces.

Tooth brushing performance in adolescents as compared to the best-practice demonstrated in group prophylaxis programs: an observational study

BackgroundResearch indicates that adolescents may have difficulties to adopt the tooth brushing recommendations delivered in prophylaxis programs. However, it is not clear whether these difficulties are seen amongst the entire age range of adolescence (10–19 years) or only occur at certain developmental stages of the adolescence. The present study analyzes the tooth brushing performance of adolescents and compares it to the best-practice of tooth brushing demonstrated during prophylaxis programs.MethodsA random sample of N = 66 adolescents, comprising 10-year-olds (n = 42) and 15-year-olds (n = 24), were asked to perform oral hygiene to the best of their abilities in front of a tablet camera. Videos were analyzed for tooth brushing duration, location, and brushing movements, and the difference between the actual and expected behaviour was tested for consistency using repeated measures ANOVAs and Student’s t-tests. For the direct comparison across different age groups, already available data from 12- and 18-year-olds were reanalysed.ResultsThe average brushing time (mean ± SD) of the 10-year-olds and 15-year-olds was 195.8 s (74.6 s) and 196.1 s (75.8 s), respectively. Regardless of age, the adolescents distributed their brushing time unevenly across the inner, outer and occlusal surfaces. The inner surfaces in particular were neglected to a considerable extent, as no age group spent more than 15.8% of the total brushing time on them. Furthermore, all age groups showed a high proportion of horizontal movements on the inner and outer surfaces, regardless of the movements instructed for the respective surfaces.ConclusionEven if adolescents brush to the best of their abilities, they neglect or skip one or many of the tooth surfaces. The reasons for the lack of compliance to tooth brushing instructions are discussed in light of the methods used in prophylaxis programs and the influence of parents.

Oral Health-Related Risk Factors Among Students in Southeast Serbia

BackgroundAn association between insufficient or irregular oral hygiene with the occurrence of dental caries, gingival/periodontal diseases, and consequently general diseases has been established.The null hypothesis that there is no difference in the oral health status among students in a preclinical medical program and those who went through a clinical medical program was tested. The main objective of the study was to analyze oral health risk factors (oral hygiene practices, attitudes, and behavior) as well as their impact on oral health by using convenience sampling.Material/MethodsWe investigated risk factors for oral health conditions by examining oral hygiene practices, attitudes, and behaviors among the students in the medical program of the University of Niš, collecting data using questionnaires. The study included 396 students of medicine, dentistry, pharmacy, and vocational studies. Participants filled out the anonymous questionnaire.ResultsIn both groups, parents were mostly employed, with the representation of employed fathers significantly higher in student group 1 (P<0.05), which is also the only statistically significant difference between the groups. In terms of oral hygiene practices, students were most often trained by parents (68.69%). A very high percentage of students brushed their teeth every day (97.22%), and 54.55% did this twice a day. Of the total number of students, 78.28% thought that it was necessary to use interdental brushes/floss/toothpick. The duration of teeth cleaning was 3 minutes in 39.39%, whereas 55.30% thought that it should be longer than 3 minutes. The most common brushing movements were combined movements and were used by 60.35% of all students. Of all students, 253 (63.89%) never smoked, 182 (49.96%) regularly went to the dentist, and 141 (35.61%) visited the dentist 6 months ago. The majority of students, 265 (66.92%), obtained the greatest amount of information about oral and tooth care from their dentist, which was the case in both age groups.ConclusionsThis study highlights oral health risk factors among students at the University of Niš. It is essential to determine their oral health knowledge, as it is of great significance both to patients and to students. Also, these students will be the major providers of health services and will be responsible for public oral health promotion. It could help in reformation of the oral health education program. The results of this research indicate that it is necessary to educate preclinical students to solve oral health issues.

Calligraphy Brush Trajectory Control of by a Robotic Arm

This study proposed a calligraphy brush trajectory model for the behavior of brush movements and provided the three-dimensional handle coordinates for a robotic arm to write calligraphy. This study dealt with basic footprints and bent lines of calligraphy and proceeded as follows. The shape of brush footprints on paper was measured, which provided the positions of the brush relative to its handle. These brush footprints were scanned and corrected for skew using the Direct Linear Transformation. The outer frame of each basic footprint was characterized using Bézier curves. Bent lines were drawn to derive the brush trajectory model, and it was used to derive the relationship between the trajectories of the brush and handle. By characterizing the changes in the footprints with handle displacement, we obtained the relationship between the handle coordinates and the position and shape of the brush footprints. The written characters were evaluated based on their size, position, and stroke balance, with a maximum score of 100 in each category. The average score of the “Yong” character written using our brush trajectory model was approximately 94 points; when the handle coordinates were fixed to the center of each footprint, the average score was only 88 points.

Study on surface quality improvement of the plane magnetic abrasive finishing process

Magnetic abrasive finishing (MAF) is an effective surface finishing method. At present, most of the research on plane MAF focuses on finishing characteristics. However, due to the “edge effect” of the magnetic field and the rotational movement of the magnetic brush, the uniformity and flatness of the finished surface are poor. In order to further improve the accuracy of the finished surface, the surface uniformity and flatness are improved by changing the shape of the magnetic pole and the trajectory of the magnetic brush. At the same time, the surface flatness is evaluated not only by the maximum height difference of the cross section but also by the standard deviation to evaluate the surface uniformity and flatness. Through magnetic field simulation and experiments, it is proved that the bottom groove of the magnetic pole helps to make the magnetic particle distribution more uniform in the processing area, which can effectively improve the surface quality. In addition, through experiments, changing the trajectory of the magnetic brush can also effectively improve the surface flatness of the finished surface.

In vitro effect of children's toothpaste on brushing abrasion of eroded primary enamel.

Emerging data have suggested that acid erosion has become an increasing clinical problem in pediatric dentistry. This study aimed to investigate the abrasive effects of two commercial toothpastes on primary enamel eroded by orange juice using an in vitro model. Thirty enamel slabs were obtained from primary teeth and then randomly assigned to three groups (n = 8) comprising two different toothpastes: G1-control-distilled water; G2-Dentifrice A (containing no fluoride); and G3-Dentifrice B (1.100 ppmF-NaF). Each slab had one half protected to provide a control side, and the other one was subjected to treatments. The slabs were submitted to daily erosive challenges (3×/day, 2min) in concentrated orange juice (pH 3.38) associated with abrasive challenges using a tooth-brushing machine (150 brush movements for each cycle). During the experimental period, the slabs were kept in 37°C artificial saliva, and the experiment was carried out for 5days. The depths of the resulting eroded areas were measured by stylus profilometry. The data were analyzed using ANOVA and the Tukey-Kramer test (α = 5%). Tooth loss (µm, mean ± SD) was 2.46 ± 1.18 for G1, 3.32 ± 2.12 for G2 and 2.14 ± 1.03 for G3. Therefore, the NaF dentifrice (Dentifrice B) produced significantly less mineral loss (p = 0.04) than dentifrice A. The findings suggest that fluoride toothpaste could protect primary enamel against erosion.

Wooam Song Si-yeol's letter calligraphy

본고는 17세기 조선의 주자학을 선도했던 우암(尤庵) 송시열(宋時烈, 1607-1689)의 간찰서예를 연구한 것이다. 우암의 한문간찰과 한글간찰의 서체를 분석하고, 간찰에 드러난 미적 요소와 그에 내재된 서예풍격을 조명하였다. 우암은 상당수의 간찰을 남겼는데, 그 가운데 몇 점을 선별해서 분석한 결과, 넉넉한 결구와 유려한 필세 및 호방한 필의가 두드러졌다. 정중한 해서에 행서의 기운을 넣어 자형의 기울기를 줌으로써 정적이고 점잖아 보이면서도 한편 필세의 자연스러운 흐름이이 돋보였다. 거리낌 없는 자유분방한 운필과 필획의 흐름, 마지막 세로획의 절묘한 비백과 탄력적인 필세, 묵직한 끝맺음 등은 초서의 멋스러움과 더불어 우암의 호방하면서도 강직한 성품을 확인할 수 있었다. 법도에 어긋남 없이 매우 경쾌한 가운데서도 절제의 미가 돋보였으며, 특히 필획의 강약변화와 필세의 다양한 흐름에서는 역동적 기운과 필단의연(筆斷意連)의 운치가 융합되어 있다. 능숙한 한문서예 필법을 토대로 서사한 우암의 한글간찰은 자간의 연결과 필맥의 흐름이 뛰어나다. 형식에 얽매이지 않고 운필과 자형, 자간과 행간 등을 자연스럽게 포치함으로써 소박한 가운데 절주미가 두드러진다. 우암의 한문필법은 그의 한글서예에도 고스란히 담겨있었다. 다만 한문 편지는 평소에 늘 사용했기 때문에 깊이 있고 웅장하고 근엄하며 자유자재로 운필하는 등필력이 지극히 느껴지는 반면, 한글간찰은 드물게 쓴 것이어서인지 섬세하면서도 부드럽고 유려함마저 느껴진다. 그럼에도 불구하고 행서와 초서의 필법에 뿌리를 두어 엄정하고 단아한 필획으로 조선시대 사대부 특유의 한글을 구현하였다. 특히 한문간찰과 한글간찰을 비교한 결과 비슷한 자형이라도 어느 획 하나 중복되거나 동일한 표현이 없어 우암 서체의 변화무쌍한 풍격을 확인할 수 있었다.This paper is to examine letter calligraphy of Wooam Song Si-yeol (尤庵宋時烈, 1607-1689), a leader of Neo-Confucianism in the 17th century Joseon. Wooam’s letter calligraphy is of remarkably restricted beauty in spite of unrestrained, free use of brush and flow of brush strokes. Particularly in dynamic change of brush strokes and diverse flows in strength of brush movement, energetic spirit and quaint beauty in discontinued strokes but continuous right attitude on calligraphy (筆斷意連) are combined. Wooam’s Korean calligraphy work, all of which are letter calligraphy, have been passed down and this study analyzed three of them. Letters written in Korean characters described on the basis on his skilled calligraphic technique for Chinese calligraphy are of superb connection between characters and flow in calligraphic context. Not restricted by formality and naturally spreading his use of brush, shape of characters, space between letters and lines, his works are artless with remarkable beauty of dynamics. Comparison between letters written in Chinese and Korean characters did not demonstrate any single stroke duplicated or repeated expression even with similar character shape, which confirmed ever-changing style of Wooam chirography.

Pattern Classification using Three Axis Accelerometer and Magnetic Sensor Toothbrush

The idea of savvy toothbrush, fit for observing brushing movement, introduction through the hold pivot, amid tooth brushing was recommended in our past investigation. In this investigation, we depict a tooth brushing design order calculation utilizing three-pivot accelerometer and three-hub attractive sensor. We have discovered that wrong tooth brushing design indicated explicit moving examples. So as to follow the position and introduction of toothbrush in a mouth, we have to know outright organize data of toothbrush. By applying tilt-repaid azimuth (heading) figuring calculation, which is commonly utilized in little telemetries gadgets, we could discover the tendency and introduction data of toothbrush. To evaluate the plausibility of the proposed calculation, 8 brushing examples were performed by 6 individual solid subjects. The proposed calculation demonstrated the discovery proportion of 98%. This investigation demonstrated that the proposed checking framework was imagined to help dental consideration faculty in patient training and guidance in oral cleanliness with respect to brushing style

Real Time Nanoscale Cleaning Phenomenon Observation during PVA Brush Scrubbing by Evanescent Field

Cleaning process is indispensable in Post chemical mechanical polishing (Post-CMP) to remove the abrasive nano-particles remaining on the polished wafer surface. There are two main types of the cleaning process. One is contact cleaning with polyvinyl alcohol (PVA) sponge brush scrubbing, and the other is non-contact cleaning enforced with mega sonic by piezoelectric unit or dual (gas-liquid phase spray) jet cleaning. We have been focusing on the phenomenon of PVA brush contact cleaning process. Generally, cleaning phenomenon is considered as abrasive nano-particle behaviors, which are removed from a wafer surface and occasionally reattach to the surface or still stay on the surface to be a residual contamination. However, these contaminations on a wafer surface are usually inspected before and after cleaning process, not during the cleaning process. Hence, we have been duplicated experimental cleaning process of thin film material on a silica glass surface, and have also been proposing a real time observing method to inspect the removal of abrasive nano-particle behaviors during the cleaning process. Because these behaviors occur in a few hundred nm range from the wafer surface. Therefore, an evanescent light that localizes on the surface being cleaned in range of a few hundred nm can be applied to limitedly optically illuminate to observe either abrasive nano-particle behaviors or PVA brush movement. By this optical illumination, the contaminated nano-particles and/or PVA brush existing in an evanescent field will scatter their evanescent field to be the propagating light, which can reach to a camera in a microscopy to visualize the brush scrubbing cleaning phenomenon (figure(a)). However, both scattering lights from PVA brush and nano-particles are same wavelength of illuminated laser. In this paper, 100±20 nm fluorescence silica-nano-particles were employed to identify the contaminated silica particles by fluorescent wavelength (λ=600 nm) that different from the illuminated laser wavelength (λ=450 nm). A typical result of optical method is shown in figure(b). A silica particle that was already adhered on a glass surface was removed by sliding of PVA brush in pure water. Evidently, fluorescence scattering light (red light intensity : λ=600 nm) and PVA brush scattering light (blue light intensity : λ=450 nm) could be distinguished in the recorded phenomenon in rate of 120 frame per second by a RGB color camera. Before coming of PVA brush, 100 nm silica particle already adhered on a glass surface. Next, PVA brush moved with a sliding speed of 2.5 mm per second by a rotation motor. Where the sliding speed was calculated by distance of PVA brush movement during 1/120 s (≈8.3 ms). Then, 100 nm silica particle was removed from surface after 33.3 ms as quantitatively shown in figure(c). These results imply that nano-particle was removing away at the same time during the attachment of PVA brush to the nano-particle or the approach near to the nano-particle. By using evanescent field and fluorescent nano-particle, we can observe nanoscale cleaning phenomenon during PVA brush scrubbing in real time. Figure 1

Determination wear intensity of electrical brushes in DC machines considering impact of collector’s surface

One of the most loaded units affecting the reliability of DC machines is the collector-brush unit. There is a continuous process of mechanical, electrical and chemical interaction of the electric brushes with the collector during operation of the DC motor, which increases the wear of the electric brushes. In a result of the analysis of the works, devoted to the study of the operation of the collector-brush unit’s elements, the authors proposed a mathematical model for determining the intensity of wear of electric brushes, which allows taking into account the effect of the collector profile on the electric brushes wear intensity. The basic data and dependencies for modelling the movement of the electric brush on the collector surface, which based on the design scheme, are presented. A distinctive feature of the developed scheme is that the elastic force at the contact of the brush with the surface of the collector is determined from the side of each collector plate. For the above scheme, a system of differential equations is compiled, allowing simulating the movement of the brush in the radial and tangential direction during its interaction with the surface of the collector. The resulting mathematical model allows us to determine the trajectory of the brush and the oscillations of the elastic force that occurs at the point of contact of the brush with the collector, with different parameters of the collector-brush unit’s elements and modes of operation of the machine, causing a certain frequency of rotation of the armature. Taking into account the above mathematical model, a software product has been developed for calculating the wear rate of DC motor electric brushes during its operation. The practical value of the work is that the use of the developed software allows you to find more optimal operating parameters for the collector-brush unit of DC motor with a minimum of time.

Design and Fabrication of Water Tank Cleaning Machine

This paper proposes to design and develop a machinery for cleaning domestic rectangular water tanks. It is known fact that cleaning of water tank is a meticulous and labor intensive task. It is very important to regularly clean and maintain the water tank to keep the water borne diseases from spreading. The water in storage units are used for both domestic and industrial purposes. The presence of toxic substances in water can also cause skin diseases. This can be avoided with the use of an efficient tank cleaning system. The system consists of a machine designed with a movable body and an extendable shaft mechanism supporting a rotating brush. The movement of shaft and brush scrubs the walls of the tank. A sprinkler mechanism rinses the sediment deposits from walls of the tank and additionally a vacuum device ingests the sludge from the floor of the tank. The object of this machine is to reduce the overall time and effort invested in the cleaning of water tanks.

Dentifrice Based on Fluoride-Hydrotalcite Compounds: Characterization and Release Capacity Evaluation by Novel In Vitro Methods.

Anti-caries activity of fluoride ions is due to the protection against demineralization and the enhancement of remineralization of tooth enamel. Dentifrices available on the market contain sodium fluoride, sodium monofluorophosphate, stannous fluoride, and amine fluoride as source of these ions. A new compound working both as fluoride ion source and as abrasive was projected. Hybrids based on F- ions intercalated between the lamellae of hydrotalcite-like compounds (HTlc-F), namely MgAl-HTlc-F and ZnAl-HTlc-F, were prepared and characterized. Then, three different percentages (2, 3, and 4%) of both HTlc-F compounds were assayed. After the rheological characterization, the dentifrices containing 3 and 4% of MgAl-HTlc-F and ZnAl-HTlc-F, respectively, resulted to be the most suitable ones. Two novel in vitro methods, "rotary toothbrush method" and "manual brushing method," were developed and used in order to study the F- ions release from the prepared dentifrices. The obtained results showed that the dentifrice containing ZnAl-HTlc-F (4%) was the most effective in releasing fluoride ions. The "rotary toothbrush method" resulted to be the most suitable as the simulation of the brushing movements is standardizable and reproducible.

Toothbrushing behavior in children \u2013 an observational study of toothbrushing performance in 12 year olds

BackgroundMany countries offer systematic group prevention programs in kindergarten and school in order to promote children’s oral health. Little is known, however, about the actual toothbrushing abilities of children when group prevention programs end.MethodsIn Germany, all children take advantage from a nationwide group prevention program (called “Gruppenprophylaxe”) lasting from kindergarten up to sixth grade (12 years of age). Standardized recommendations are given concerning brushing systematics and brushing movements. N = 174 children at the age of 12 were thus randomly selected from two German towns and were asked to perform toothbrushing to the best of their abilities in front of a mirror which also served as a camera. Brushing behavior was analyzed by video analysis.ResultsChildren brushed their teeth for an average of 200 s ± 80.48 s (mean ± SD). Still, more than 55% missed at least one sextant when brushing inner surfaces, 16% missed them all. Only 7.5% of the children brushed both inner and outer surfaces by the intended movements (vertical movements on the inner surfaces and circular movements on the outer surfaces) for at least 90% of the respective brushing time. Instead, horizontal brushing was very common on the lateral surfaces.ConclusionsThe present analysis indicates that children have low efficiency to adopt the tooth-brushing recommendations given in prevention programs. This is surprising as great endeavors are made to help children internalize the recommendations. Future research is needed to better understand which factors impede adoption of toothbrushing recommendations in children and which efforts are necessary to improve their toothbrushing abilities.

Prevalence and predictive factors of dentin hypersensitivity in Brazilian adolescents.

To measure the prevalence of dentin hypersensitivity (DH) in adolescents. The diagnosis was based on self-report and was confirmed by tactile and evaporative tests. The association between DH and predictor factors was determined using a multivariate model. The sample consisted of 384 adolescents. The prevalence was 19.0%. DH prevalence to tactile stimulus was higher in those participants whose toothbrush movement was vertical/horizontal (OR=0.53, 95% CI=0.47-0.60, p<0.001), in the presence of dental biofilm (OR=2.45, 95% CI=1.94-3.09, p<0.001), of non-carious cervical lesion (OR=2.76, 95% CI=2.40-3.18, p<0.001), of gingival recession (OR=1.63, 95% CI=1.44-1.86, p<0.001) and gyroversion (OR=1.60, 95% CI=1.40-1.82; p<0.001). When DH was diagnosed by evaporative stimulus, there was an association with brush movement in a vertical/horizontal direction (OR=0.73, 95% CI=0.66-0.82, p<0.001), with the use of mouthwash solutions (OR=2.65, 95% CI=2.16-3.25, p<0.001), in the presence of non-carious cervical lesion (OR=1.75, 95% CI=1.57-1.96, p<0.001), of gyroversion (OR=1.75, 95% CI=1.51-1.90, p<0.001) and gingival recession (OR=1.78, 95% CI=1.59-1.99, p<0.001). The prevalence of DH in the sample was worrying, since almost 1 in 5 adolescents had DH. Individuals with DH were more likely to report traumatic dental brushing, and presence of dental biofilm, non-carious cervical lesion, gingival recession and gyroversion in the affected teeth.