A thirty months clinical evaluation of a posterior composite resin in primary molars

The purpose of this in vivo study was to evaluate the clinical performance of a posterior composite resin TRH (Caulk Dentisply) in class I restorations in primary molars. A total of 30 children aged 5 to 8 years old with 49 class I dental lesions in primary molars participated in the study. The cavity preparations involved removal of carious lesion only and the enamel margins were beveled. The results showed after 30 months that, 82% (32/39) of Alfa ratings and 18% (7/39) of Bravo ratings. We concluded that the composite resin TP-H could be used in conservative restorations in primary molars, particularly in the late mixed dentition.

Treatment of traumatized permanent incisors with crown and root fractures: A case report

A case report of the treatment of permanent incisors with crown and root fractures is presented. A radiolucent lesion at the fracture lines was treated with calcium hydroxide in the coronal fragments for 18 months. Clinically, the teeth became firm and the radiographic results after 2 years showed healing of the lesion and hard tissue filling in the space at the fracture lines. © Munksgaard, 2001.

Biometric analysis of the maxillary permanent molar teeth and its relation to furcation involvement.

A high rate of root exposure and consequently the exposure of the furcation area is usually observed in multirooted teeth. In maxillary molar teeth, this fact may endanger the three existent furcations (buccal, mesial and distal), causing serious problems. In this research, distance measures from the buccal furcation to the mesial (F1M) and distal (F1D) surfaces of the mesio-buccal and disto-buccal roots; from the mesial furcation to the buccal (F2B) and palatal (F2P) surfaces of the mesio-buccal and palatal roots and from the distal furcation to the buccal (F3B) and palatal (F3P) surfaces of the disto-buccal and palatal roots, respectively were established. One hundred maxillary first molar teeth were used, 50 of the right and 50 of the left side. Reference marks and demarcations were determined on the furcations and also on the root surfaces involved in the measures. We concluded that these measurements are important because they may effectivelly contribute to diagnosis, prevention and treatment of periodontal problems.

Unusual anatomy of permanent maxillary molars

The purpose of this study was to show anatomical variations in permanent maxillary molars. Two clinical cases of four-rooted maxillary molars and a macroscopic study of an extracted tooth, showing a five-rooted maxillary molar, are presented.

Short-term treatment effects produced by the herbst appliance in the mixed dentition

This prospective clinical investigation evaluates the dentoalveolar and skeletal cephalometric changes produced by the Herbst appliance during treatment of mixed dentition patients with Class II division 1 malocclusion. Thirty individuals (15 male and 15 female individuals; initial mean age nine years 10 months) were treated with the Herbst appliance for a period of 12 months. For comparison, the records of 30 untreated Class II children (15 boys, 15 girls; initial mean age nine years eight months) were followed without treatment for a period of 12 months. The results indicated that the treatment effects produced in the mixed dentition patients were primarily dentoalveolar in nature. The mandibular incisors were tipped labially, and the maxillary incisors were retruded; a significant increase in mandibular posterior dentoalveolar height occurred, and there was a restriction in the vertical development of the maxillary molars. There was no difference in the forward growth of the maxilla between the two groups. In comparison with the controls, however, the Herbst treatment produced a modest but statistically significant increase in total mandibular length. This increase in total mandibular length, however, was less than that observed in adolescent Herbst patients in other studies. © 2005 by The EH Angle Education and Research Foundation, Inc.

Direct and simultaneous determination of As, Cu, and Pb in Brazilian sugar cane spirits by graphite furnace AAS using tungsten permanent modifier with co-injection of Pd/Mg(N03)2

A method was developed using the multi-element graphite furnace atomic absorption spectrometry technique for the direct and simultaneous determination of As, Cu, and Pb in Brazilian sugar cane spirit (cachaça) samples. Also employed was the end-capped transversely heated graphite atomizer (THGA) with platforms pre-treated with W permanent modifier and co-injection of Pd/Mg(N03)2. Pyrolysis and atomization temperature curves were established in a cachaça medium (1+1; v/v) containing 0.2% (v/v) HN03 and spiked with 20 μg L-1 As and Pb and 200 μg L-1Cu. The effect of the concentration of major elements usually present in cachaça matrices (Ca, Mg, Na, and K) and ethanol on the absorbance of As, Cu, and Pb was investigated. Analytical working solutions of As, Cu, and Pb were prepared in 10% (v/v) ethanol plus 5.0 mg L-1 Ca, Mg, Na, and K. Acidified to 0.2% (v/v) HNO3, these solutions were suitable to build calibration curves by matrix matching. The proposed method was applied to the simultaneous determination of As, Cu, and Pb in commercial sugar cane spirits. The characteristic mass for the simultaneous determination was 16 pg As, 119 pg Cu, and 28 pg Pb. The pretreated tube lifetime was about 450 firings. The limit of detection (LOD) was 0.6 μg L-1As, 9.2 μg L-1 Cu, and 0.3 μg L-1Pb. The found concentrations varied from 0.81 to 4.28 μg L-1As, 0.28 to 382 mg L-1 Cu and 0.82 to 518 μg L-1 Pb. The recoveries of the spiked samples varied from 94-112% (As), 97-111% (Cu), and 95-101% (Pb). The relative standard deviation (n=12) was 6.9%, 7.4%, and 7.7% for As, Cu, and Pb, respectively, present in a sample at 0.87 μgL-1, 0.81 mgL-1, and 38.9 μgL-1concentrations.

Dental age in patients with Down syndrome

The aim of this research was to evaluate dental age in 102 patients with Down Syndrome, using panoramic radiographs. A software program developed by the Discipline of Radiology, School of Dentistry of São José dos Campos, São Paulo State University (UNESP), was used. A table of mineralization chronology of permanent teeth among Brazilians conceived by Nicodemo, Moraes and Medici Filho was used within the software. Statistical analysis of the results showed that 70.91% of the males land 61.21% of the females presented advanced dental age. Only 32.09% of the males and 39.79% of the females presented delayed dental age. Regarding the differences between the dental and chronological ages, two thirds of the males and females presented dental age with differences of up to 12 months, which means that they can be considered to be within normal standards, whereas only 18.87% of the males and 10.21% of the females presented dental age outside normal standards, with differences of over 24 months. In conclusion, the majority of the patients with Down Syndrome were considered to be within the normal standards of mineralization chronology.

Permanent Magnet Hall Thruster for satellite orbit raising with low power energy consumption

Electric propulsion is now a succeful method for primary propulsion of deep space long duration missions and for geosyncronous satellite attitude control. Closed Drift Thruster, so called Hall Thruster or SPT (Stationary Plasma Thruster), was primarily conceived in USSR (the ancient Soviet Union) and, since then, it has been developed by space agencies, space research institutes and industries in several countries such as France, USA, Israel, Russian Federation and Brazil. In this work we present the main features of the Permanent Magnet Hall Thruster (PMHT) developed at the Plasma Laboratory of the University of Brasilia. The idea of using an array of permanent magnets, instead of an electromagnet, to produce a radial magnetic field inside the plasma channel of the thruster is very significant. It allows the development of a Hall Thruster with power consumption low enough to be used in small and medium size satellites. Description of a new vacuum chamber used to test the second prototype of the PMHT (PHALL II) will be given. PHALL II has an aluminum plasma chamber and is smaller with 15 cm diameter and will contain rare earth magnets. We will show plasma density and temperature space profiles inside and outside the thruster channel. Ion temperature measurements based on Doppler broadening of spectral lines and ion energy measurements are also shown. Based on the measured plasma parameters we constructed an aptitude figure of the PMHT. It contains the specific impulse, total thrust, propellant flow rate and power consumption necessary for orbit raising of satellites. Based on previous studies of geosyncronous satellite orbit positioning we perform numerical simulations of satellite orbit raising from an altitude of 700 km to 36000 km using a PMHT operating in the 100 mN - 500 mN thrust range. In order to perform these calculations integration techniques were used. The main simulation paraters were orbit raising time, fuel mass, total satellite mass, thrust and exaust velocity. We conclude comparing our results with results obtainned with known space missions performed with Hall Thrusters. © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

Técnica do grupo focal como método de avaliação do conhecimento de adolescentes sobre saúde bucal

This study aims to the understanding of adolescents regarding oral health, using the Focus Group technique. The study was conducted at three public schools in the city of Araçatuba, São Paulo State, Brazil, with ten students in each. In order to conduct the focus groups, the following words, which featured high error levels, were addressed in survey questions on oral health: oral health; plaque, permanent teeth; fluoride; gum bleeds?; dental floss; transmission of cavities. During the discussions in the focus groups, it was observed that many teenagers were surprised at the situation to which they were submitted and at the topic they were discussing. The word 'oral health' was associated with the condition of cleanliness of the oral cavity, not identifying oral health as part of general health. The term 'transmission of cavities' did not have a sufficient understanding. The term 'permanent tooth' was well understood and was associated with a type of tooth that would not be replaced. The word 'fluoride' had more association with the task of cleaning than protection of the teeth. It is concluded that the use of the focus group technique is of great importance in the interpretation of the knowledge of adolescents on oral health and the appropriateness of the terminology of questionnaires on the same subject.

Overjet and overbite analysis during the eruption of the upper permanent incisors.

ABSTRACT The purpose of this study was to analyze the overjet and overbite behavior during eruption of the upper permanent incisors. Fourth-eight plaster casts of 16 patients from ages 6-13 years were appraised longitudinally. It was found that the overjet remains constant, starting at the eruption of the upper permanent central incisors until eruption of the upper permanent canine teeth, while the overbite increases after eruption of the upper permanent lateral incisors and remains constant with the eruption of the canine teeth.

A HPF AC-AC converter for Permanent Magnet Generator applications

This paper describes the design and development of a high input power-factor (HPF) AC to AC converter for naval applications using Permanent Magnet Generator (PMG). The proposed converter comprises an isolated three-phase uncontrolled multipulse rectification stage directly connected to a single-phase inverter stage, without the use of DC to DC intermediary stage, resulting in more simplicity for the overall circuitry, assuring robustness, reliability and reduced costs. Furthermore, the multipulse rectifier stage is capable to provide high power factor and input currents with low total harmonic distortion (THD). The output voltage of the PMG varies from 260V rms (220 Hz) to 380V rms (360 Hz), depending on load conditions. The output single-phase inverter stage was designed to operate with wide range of DC bus voltage, maintaining 120V rms, 60 Hz output. Measured total harmonic distortion for the AC output voltage represents less than 2%, at 3.6kW nominal linear load. © 2010 IEEE.

Avaliação das dimensões transversas na maxila e mandíbula em pacientes na fase da dentição mista tratados com aparelho ortodôntico removível superior

Objeti vo: Avaliar os efeitos da expansão lenta na maxila e na mandíbula com o aparelho ortodônti co removível superior com torno de expansão simétrico e mediano, nas regiões oclusal, gengival e alveolar de pacientes jovens com atresia maxilar. Método: A amostra compreendeu 18 indivíduos leucodermas (11 meninas e 7 meninos; idade média: 8 anos e 10 meses no início do tratamento) que apresentavam atresia da maxila, acompanhadas ou não de mordida cruzada posterior uni ou bilateral na fase de denti ção mista. Todos os pacientes foram tratados com aparelho ortodônti co removível superior com torno de expansão simétrico e mediano, sendo o tempo médio de tratamento de 15,4 meses (± 7,6). Para avaliar a infl uência do tratamento nas mensurações dos pontos demarcados nas regiões oclusal, gengival e alveolar, foram uti lizados os modelos de gesso dos arcos superior e inferior (36 pares) obti dos em dois tempos: T1: início do tratamento e T2: ao fi nal do tratamento. Para cada paciente em ambos os tempos, foram mensuradas as distâncias transversas na região oclusal entre caninos decíduos, 1o molares decíduos ou 1o pré-molares permanentes e entre 1o molares permanentes, superiores e inferiores. Para verifi car se a movimentação ocorreu por inclinação ou por movimento de corpo, foram uti lizadas também medidas nas regiões gengival e alveolar. Os dados foram avaliados estati sti camente pelo teste “t student para amostras pareadas (5%). Resultados: Observou-se que em T2, todas as distâncias mensuradas para as regiões oclusal, gengival e alveolar apresentaram valores estati sti camente superiores às mesmas medidas em T1 (p<0,05). Conclusão: O aparelho ortodônti co removível superior é efeti vo nos casos de expansão lenta da maxila, agindo também indiretamente nas dimensões transversas do arco inferior.

Developmental Disturbance of an Unerupted permanent incisor due to trauma to its predecessor

Developmental disturbances of permanent teeth can result from trauma to primary teeth because of the proximity of the root of the primary teeth to their permanent successors. We describe the case of a 14-month-old boy who was referred to the baby clinic of the School of Dentistry, Universidad Estadual Paulista, Araçatuba, Brazil, after sustaining a severe trauma that led to intrusion of the right primary central incisor. Radiographic examination 4 years after the trauma showed a developing morphological change in the germ of the permanent successor. On eruption of the permanent central incisor, a crown malformation along with enamel hypoplasia was observed. We concludethat radiographic follow-up is indicated after trauma to monitor possible sequelae in the permanent successors even before their eruption. © 2011 Canadian Dental Association.

Prevalence and microscopic features of enamel pearls from permanent human molars

Enamel pearls are ectopic structures observed mainly on the roots of permanent teeth and could be related to periodontal diseases. Aim: To evaluate the prevalence of enamel pearls in extracted human molars and characterize their structures using light and scanning electron microscopy. Methods: The study comprised 2,201 extracted human permanent molars. The teeth were analyzed and classified according to morphological features. The presence, location and shape of enamel pearls were investigated. Fifteen human molars with enamel pearls were embedded in acrylic resin and observed by light microscopy. Results: Seventy-one enamel pearls were identified on third molar root. Microscopically, most pearls were composed of prismatic irregular enamel and normal dentin. The dentinoenamel junction presented an irregular course. The number of dentinal tubules was normal and they presented curvature to continue within the root dentin of the carrier tooth. Dentinal tubules below the enamel pearls were closer to each other. Conclusions: Scanning electron microscopic analysis revealed that the enamel pearls were similar to coronal enamel.

Apexification with white MTA in an immature permanent tooth with dens invaginatus

Dens invaginatus, also known as dens in dente, is a developmental dental anomaly resulting in an invagination of the enamel organ into the dental papilla. These cases present technical difficulties to the root canal treatment. Apexification using an apical plug of mineral trioxide aggregate (MTA) has been indicated as an alternative to long-term intracanal use of calcium hydroxide in immature permanent teeth. It is considered as a simple and rapid technique. This paper reports a case of Oehlers' Type 1 dens invaginatus in an immature permanent maxillary right lateral incisor, which presented pulp necrosis secondary to dental trauma and was treated by apexification with white MTA apical plugging followed by conventional root canal therapy. The operative procedures are described and the technique is discussed. The physical and biological properties of MTA, associated with appropriate instrumentation and obturation techniques, make this material an excellent option in the endodontic therapy of immature permanent teeth with dens invaginatus.