Influence of physical assessment of different light-curing units on irradiance and composite microhardness top/bottom ratio.

The aim of this study was to evaluate the influence of the physical assessment of different light-curing units from 55 dental offices on the irradiance and composite microhardness top/bottom ratio, and the influence of the radiometers for LED or QTH light sources on irradiance measurement. The irradiance of each light-curing unit was evaluated with two radiometers, either for LED or QTH light. A questionnaire regarding the type of source (LED or QTH), time of use, date of last maintenance and light-curing performance assessment applied. The physical assessments were evaluated regarding damage or debris on the light tip. For each light-curing unit, three composite specimens were made (diameter = 7 mm; thickness = 2 mm) with polymerizing time of 20 s, in order to perform the microhardness (Knoop) test. Data were analyzed by Kruskal-Wallis and Dunn test (α = 0.01). There was wide variation in irradiance (0-1000 mW/cm(2)). Approximately 50 % of the light-curing units presented radiation lower than 300 mW/cm(2); 10 % of light-curing units, especially those with LED source, presented values higher than 800 mW/cm(2), and 43 % of light-curing units worked with adequate irradiance between 301 and 800 mW/cm(2). In almost 60 % of cases, no maintenance of light-curing units was performed in a period of 3 to 10 years. The age of the light-curing units and the use of inadequate tips interfered negatively in irradiance. The data emphasize the importance of periodic maintenance of light-polymerizing, light-curing units.

Gingival retraction: thickness measurement and comparison of different cords / Afastamento gengival: mensuração e comparação da largura de diferentes fios retratores

Objetivo: medir a espessura de cinco diferentes marcas de fio afastador e verificar se há relação entre os tamanhos e as numerações designadas, e se há um coerente aumento da espessura entre os fios de menor para os de maior espessura. Materiais e Métodos: os fios avaliados foram Gengiret (G), Retraflex (RF), Retractor (RT), Ultrapack (UP) e Pro Retract (PR). Pedaços dos fios foram posicionados ao lado de uma régua metálica e fotografados de forma padronizada quanto à distância e iluminação. A mensuração das espessuras foi realizada com software para edição de imagens (Adobe Photoshop CS6 - Adobe Systems, San Jose, CA, EUA). Os dados apurados foram submetidos à análise estatística (ANOVA fator único e teste post hoc de Sheffé (p = 0,05)). Resultados: não houve coincidência entre a numeração comum dada pelos diferentes fabricantes e a espessura observada para a maioria das marcas de fios retratores avaliadas. Observou-se que duas das marcas (UP e PR) apresentaram aumento na espessura que não respeitou uma progressão de tamanho consistente entre o fio de menor e o de maior espessura. Conclusão: a designação comum dada pelos fabricantes aos fios não se reflete em padronização das espessuras, o que determina que o clínico observe o risco de utilizar fios de diferentes marcas durante um procedimento de afastamento gengival nas técnicas que indicam o uso de mais do que um fio afastador.

Objective: To measure the thickness of five different brands of gingival retraction cords and verify whether therewouldbe a relationshipamong the sizes andtheir numbers and a coherent increasing from the thinnest to the largest thickness. Material and Methods: the following cords were evaluated: Gengiret(G), Retraflex(RF), Retractor(RT), Ultrapack(UP), and Pro Retract(PR). Pieces of the cords were placed beside a metallic ruler and photographed standardly regarding to the distance and light. The measurements of the thickness were performed through imaging software (Adobe Photoshop CS6 - Adobe Systems, San Jose, CA, USA). The obtained data were submitted to statistical analysis (one-way ANOVA and post hoc Sheffé test (p = 0.05)). Results: The number and the thickness of the cords mismatched for most of the brands evaluated. Two brands (UP and PR) showed a thickness increasing that mismatched the size increasing between the thinnest and largest cord. Conclusion: The number assigned to the cords by the manufactures did not correspond to a standard thickness, so that the dentist must observe the risk of using cords from different brands during gingival retraction procedures during techniques requiring more than one retraction cord.

Precisão de medições lineares em tomografias computadorizadas por feixe cônico e helicoidal, realizadas em mandíbulas humanas / Accuracy of linear bone measurements cone-beam and spiral computed tomography in human mandibles

Introdução: a obtenção de métodos de imagem capazes de reproduzir com adequada precisão as dimensões maxilomandibulares é de vital importância para o diagnóstico e o planejamento seguro de procedimentos cirúrgicos. Objetivo: verificar, in vitro, a precisão de medições lineares de um exame de tomografia computadorizada helicoidal e de dois sistemas de tomografia computadorizada por feixe cônico. Método: dez mandíbulas humanas secas foram submetidas a três diferentes exames de tomografia: CBCT i-CAT, CBCT NewTom 3G e HCT helicoidal Picker CT Twin Flash. As medições realizadas diretamente na mandíbula foram feitas com um paquímetro digital, e as tomográficas por meio do software ImplantViewer 2.604. Foram mensuradas seis regiões de cada mandíbula seca, sendo agrupadas em duas regiões de primeiro molar inferior (Sítio PMI), duas regiões de primeiro pré-molar inferior (Sítio PPMI) e em duas regiões de incisivo lateral inferior (Sítio ILI). Resultados: nos sítios ILI e PPMI, as três tomografias estudadas demonstraram precisão semelhante entre si. No sítio PMI, a CBCT i-CAT mostrou-se mais precisa que as dos demais sistemas. Conclusão: pode-se concluir que nos sítios ILI e PPMI as três TCs estudadas apresentam limites de concordância e de precisão semelhantes, e que no sítio PMI a CBCT i-CAT apresentou um limite de concordância de menor amplitude, sendo mais precisa que a dos demais exames.

Availability of imaging methods able to accurately reproducing the maxillo-mandibular dimensions is important for diagnosis and safe planning of surgical procedures. Aim: The aim of this in vitro study was to verify the accuracy of linear measurements in images obtained with a system of spiral and two systems of cone-beam computed tomography (CT). Methods: Ten dry human mandibles were subjected to three different CT scans: I-Cat® CBCT, NewTom-3G® CBCT, and Picker® SCT. Measurements in the mandible were made with a digital caliper and measurements in the images were made with the ImplantViewer® software. Six regions were measured in each dry mandible, being distributed into two regions in each of the lower first molar (LFM), lower first pre-molar (LFPM), and lower lateral incisor (LLI) sites. Results: Similar accuracy was observed among the three images at sites LLI and LFPM. Measurements obtained with the I-Cat CBCT scan at site LFM were shown to be more accurate than the those obtained with the other two CT scan systems. Conclusions: It can be concluded that the three CTs studied herein showed similar limits of agreement and precision at sites LLI and LFPM, and I-Cat CBCT showed limits of agreement with smaller amplitude and greater accuracy than other examinations performed at site LFM. Conclusion: It can be concluded that the three CTs studied herein showed similar limits of agreement and precision at sites LLI and LFPM, and ICat CBCT showed limits of agreement with smaller amplitude and greater accuracy than other examinations performed at site LFM.

Flexural properties of resin composites: influence of specimen dimensions and storage conditions.

This study evaluated the influence of specimen dimensions and storage medium and temperature on the flexural properties of one dental resin composite. The material utilized throughout the study was Clearfil AP-X. Eighty specimens were built with dimensions of either 10×2×2 mm or 25×2×2 mm, stored dry or in distilled water, at 25 or 37ºC, for 24 h. Flexural strength and modulus were tested in three-point bending. Results were evaluated with three-way ANOVA and Tukey's test (α=0.05). Statistical significance was observed for all three factors: temperature (37ºC=190.8 MPa, 25ºC=165.3 MPa; p<0.01), storage medium (water=167.7 MPa, Dry=188.4 MPa; p<0.01) and specimen dimensions (10×2×2 mm=197.9 MPa, 25×2×2 mm=158.2 MPa; p<0.01). None of the interactions were significant. Within the limitations of this study, it can be concluded that factors such as specimen dimensions, storage medium and temperature significantly affect flexural strength results, which invalidates comparisons of results from studies that use different methodologies.

In vitro study on the influence of the light polymerization technique and appliance on the bond strength of intra-radicular posts / Estudo in vitro da influência da técnica e do aparelho de fotopolimerização sobre a resistência de união de pinos intra-radiculares

The purpose of this study is to verify the influence of light curing type on retention force of direct technique and direct-indirect technique.Forty bovine single root teeth with 12mm length were used in this study. Roots were endodontically treated and randomly divided into four groups according to the light curing unit and the technique used: group HD (direct technique, halogen lamp), group LD (direct technique, LED), group HI (direct-indirect technique, halogen lamp), group LI (direct-indirect technique, LED). Retention force was determined using a Universal Testing Machine (Instron). All data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test. After the test, failure was examined and classified according to the fracture place: post/ resin; resin/dentin; mix. Group HI (246.05N ± 29.51) and LI (241.60N ± 28.95) did not show difference statistically but presented higher retention force than group HD (142.30N ± 25.60) and LD (178.56N ± 25.67). Most of fracture occurred in interface between dentin/resin. Based on the obtained results, it was concluded that adhesive cementation technique influenced in the retention of glass fiber post

O objetivo deste estudo foi avaliar a influência do tipo de luz sobre força de adesão de pinos feitos pela técnica direta ou indireta. Quarenta dentes bovinos unirradiculares com 12 milímetros de comprimento foram utilizadas neste estudo. As raízes foram tratadas endodonticamente e divididas aleatoriamente em quatro grupos de acordo com a unidade de fotoativação e técnica utilizada: grupo 1 (técnica direta, lâmpada halógena), grupo 2 (técnica direta, LED), grupo 3 (técnica direta indireta, lâmpada halógena ), grupo 4 (técnica direta indireta, LED). A força de retenção foi determinada utilizando-se uma máquina universal de ensaios (Instron). Todos os dados foram analisados pela análise de variância (ANOVA) e teste de Tukey. Após o teste, as falhas foram analisadas e classificadas de acordo com o local de fratura: pino / resina; resina / dentina ou mista. Os Grupos 3 (246,05 N ± 29,51) e 4 (241,60 N ± 28,95) não apresentaram diferenças estatísticas entre si, mas apresentou maior força de retenção que os grupos 1 (142,30 N ± 25, 60) e 2 (178,56 ± 25,67 N). A maioria das fraturas ocorreu na interface entre a dentina / resina. Com base nos resultados obtidos, concluiu-se que a técnica de cimentação adesiva influenciou na retenção dos pinos de fibra de vidro

Evaluation of the possibility of removing staining by repolishing composite resins submitted to artificial aging.

This in vitro research verified the possibility of eliminating staining caused by coffee and red wine in five composite resins, after being submitted to thermal cycling. Thirty-six specimens were prepared and immersed in water at 37°C for 24 hours. After polishing, specimen color was measured in a spectrophotometer Cintra 10 UV (Visible Spectrometer, GBC, Braeside, VIC, Australia). All specimens were submitted to thermal cycling at temperatures of 5 and 55°C with a dwell time of 1 minute, for 1,000 cycles in a 75% ethanol/water solution. After thermal cycling, the specimens were immersed in water at 37°C until 7 days had elapsed from the time the specimens were prepared. All specimens were then taken to the spectrophotometer for color measurement. The specimens were divided into three groups (N = 12): distilled water (control), coffee, and red wine. For the staining process to occur on only one surface, all the sides, except one, of the surfaces were isolated with white wax. The specimens were immersed in one of the solutions at 37°C for 14 days. The specimens were dried and taken to the spectrophotometer for color measurement. After this, the specimens were submitted to 20 µm wear three times, and the color was measured after each one of the wear procedures. Calculation of the color difference was made using CIEDE2000 formula. According to the methodology used in this research, it was concluded that the staining caused by coffee and red wine was superficial and one wear of 20 µm was sufficient to remove the discoloration.

Cor sem mistérios para o clínico / Color management for the clinician

A observação e interpretação da cor dos dentes têm se tornado um desafio proporcionalmente maior na medida em que os materiais dentários passam por um processo de sofisticação. As primeiras resinas compostas pasta/pasta apresentavam uma diminuta variedade de cores com uma opacidade intermediária. Apesar disso, os resultados eram satisfatórios. Para os pacientes, o que valia era livrarem-se das restaurações metálicas, substituindo-as por algo com a "cor do dente': Com a introdução de materiais cerâmicos e resinas compostas com uma ampla gama de alternativas quanto às cores e à translucidez/opacidade, a seleção da cor correta tornou-se complexa. Isso foi acompanhado por uma mudança na percepção e exigência de muitos pacientes que desejam restaurações com aspecto natural e que sejam imperceptíveis. Some-se ao aspecto cor a importância que a forma e a textura da superfície apresentam no resultado final de qualquer trabalho restaurador estético. Este artigo objetiva desenvolver esses temas e apresentar um protocolo para o processo de seleção da cor.

Teeth shade determination and interpretation has become a greater challenge as dental materiais underwent an impressive aesthetic enhancement. When composites were first introduced, they presented a small variety of colors and only one intermediate translucency. Nevertheless, the results were satisfactory. At that time, patients were glad as they were able to get rid of the unpleasant metallic restorations and replace them with a "tooth-colored" material. Nowadays, after the introduction of ceramic materiais and composites with a wide range of alternatives regarding color and translucency, shade matching has become more intricate. Pa- tients are also more demanding. They desire natural-Iooking and "invisible" restorations. Besides color, restoration shape and surface texture also contribute to the aesthetic result. This article aims to discuss these topics and also present a protocol to help clinicians during shade matching procedures.

Fracture strength of teeth restored with ceramic inlays and overlays.

This study evaluated the fracture strength of teeth restored with bonded ceramic inlays and overlays compared to sound teeth. Thirty sound human maxillary premolars were assigned to 3 groups: 1- sound/unprepared (control); 2- inlays and 3- overlays. The inlay cavity design was Class II MOD preparation with an occlusal width of 1/2 of the intercuspal distance. The overlay cavity design was similar to that of the inlay group, except for buccal and palatal cusp coverage The inlay and overlay groups were restored with feldspathic porcelain bonded with adhesive cement. The specimens were subjected to a compressive load until fracture. Data were analyzed statistically by the Kruskal-Wallis test at 5% significance level. The fracture strength means (KN) were: Sound/unprepared group = 1.17, Inlay group= 1.17, and Overlay group = 1.14. There were no statistically significant differences (p>0.05) among the groups. For inlays and overlays, the predominant fracture mode involved fragments of one cusp (70% of simple fractures). The fracture strength of teeth restored with inlay and overlay ceramics with cusp coverage was similar to that of intact teeth.

Fracture strength of teeth restored with ceramic inlays and overlays

This study evaluated the fracture strength of teeth restored with bonded ceramic inlays and overlays compared to sound teeth. Thirty sound human maxillary premolars were assigned to 3 groups: 1- sound/unprepared (control); 2- inlays and 3- overlays. The inlay cavity design was Class II MOD preparation with an occlusal width of 1/2 of the intercuspal distance. The overlay cavity design was similar to that of the inlay group, except for buccal and palatal cusp coverage The inlay and overlay groups were restored with feldspathic porcelain bonded with adhesive cement. The specimens were subjected to a compressive load until fracture. Data were analyzed statistically by the Kruskal-Wallis test at 5 percent significance level. The fracture strength means (KN) were: Sound/unprepared group = 1.17, Inlay group= 1.17, and Overlay group = 1.14. There were no statistically significant differences (p>0.05) among the groups. For inlays and overlays, the predominant fracture mode involved fragments of one cusp (70 percent of simple fractures). The fracture strength of teeth restored with inlay and overlay ceramics with cusp coverage was similar to that of intact teeth.

Este estudo avaliou a resistência à fratura de dentes restaurados com inlays e overlays de cerâmicas comparadas a dentes íntegros. Trinta pré-molares humanos íntegros foram divididos em 3 grupos: 1-Dentes sem preparo cavitário (controle), 2-Inlays e 3-Overlays. O preparo para as inlays apresentava uma cavidade de Classe II MOD tendo caixa oclusal com largura de metade da distância intercuspídica. O preparo para as overlays era semelhante ao das inlays; porém com cobertura das cúspides vestibular e palatina. Os grupos 2 e 3 foram restaurados com porcelanas feldspáticas fixadas com cimento resinoso. As amostras foram submetidas à compressão até a fratura. Os valores médios de fratura (KN) foram: grupo 1 = 1,17, grupo 2 = 1,17 e grupo 3 = 1,14. O teste de Kruskal-Wallis não revelou diferença estatisticamente significante entre os 3 grupos (p>0,05). Para as inlays e overlays, a predominância das fraturas envolveu fragmentos de uma das cúspides (70 por cento de fraturas simples). Concluiu-se que os dentes restaurados com inlays e overlays apresentaram resistência da cúspide comparável aos dentes intactos.

Avaliação, pelo método digital, da alteração de cor decorrente de ressecamento / Digital evaluation of color change caused by tooth desiccation

Durante alguns atos operatórios, quando se utiliza o isolamento absoluto ou relativo, o dente sofre desidratação e com ela pode haver uma alteração da sua cor, que é crítica para os procedimentos estéticos. Este estudo in vivo avaliou o efeito da desidratação na alteração de cor em incisivos centrais vitais hígidos. Participaram 20 pacientes, com idades entre 20 e 40 anos. Foram tiradas 11 fotografias com uma câmera digital Canon EOS 20D, com lentes de 18-55 mm e 58 mm de diâmetro. As imagens foram inseridas e normalizadas no software Adobe Photoshop. Observou-se alteração de cor em todas as amostras. No entanto, não se observou um padrão de alteração. Podemos concluir também que a máquina digital pode ser usada para avaliação da alteração de cor, desde que se use um padrão conhecido.

When using field isolation the teeth suffers desiccation that may lead to a color change that compromise the esthetic quality of restorative procedures. ln this in vivo study the effect of color change on maxillary central incisors was evaluated in 20 patients with age ranging from 20 to 40 years. Eleven pictures were taken. A digital camera Canon EOS 20D and lenses with 18-55 mm and 58 mm diameter were used. The software Adobe Photoshop was used for image acquisition and subsequent image processing. Color change was observed in all samples. However, a pattern was not observed. We can also conclude that the digital camera can be used to evaluate color change when a known standard is used.

Microhardness assessment of different commercial brands of resin composites with different degrees of translucence.

Owing to improvements in its mechanical properties and to the availability of shade and translucence resources, resin composite has become one of the most widely used restorative materials in present day Dentistry. The aim of this study was to assess the relation between the surface hardness of seven different commercial brands of resin composites (Charisma, Fill Magic, Master Fill, Natural Look, Opallis, Tetric Ceram, and Z250) and the different degrees of translucence (translucid, enamel and dentin). Vickers microhardness testing revealed significant differences among the groups. Z250 was the commercial brand that showed the best performance in the hardness test. When comparing the three groups assessed within the same brand, only Master Fill and Fill Magic presented statistically significant differences among all of the different translucencies. Natural Look was the only one that showed no significant difference among any of the three groups. Charisma, Opallis, Tetric Ceram and Z250 showed significant differences among some of the tested groups. Based on the results found in this study, it was not possible to establish a relation between translucence and the microhardness of the resin composites assessed. Depending on the material assessed, however, translucence variation did affect the microhardness values of the resin composites.

Microhardness assessment of different commercial brands of resin composites with different degrees of translucence

Owing to improvements in its mechanical properties and to the availability of shade and translucence resources, resin composite has become one of the most widely used restorative materials in present day Dentistry. The aim of this study was to assess the relation between the surface hardness of seven different commercial brands of resin composites (Charisma, Fill Magic, Master Fill, Natural Look, Opallis, Tetric Ceram, and Z250) and the different degrees of translucence (translucid, enamel and dentin). Vickers microhardness testing revealed significant differences among the groups. Z250 was the commercial brand that showed the best performance in the hardness test. When comparing the three groups assessed within the same brand, only Master Fill and Fill Magic presented statistically significant differences among all of the different translucencies. Natural Look was the only one that showed no significant difference among any of the three groups. Charisma, Opallis, Tetric Ceram and Z250 showed significant differences among some of the tested groups. Based on the results found in this study, it was not possible to establish a relation between translucence and the microhardness of the resin composites assessed. Depending on the material assessed, however, translucence variation did affect the microhardness values of the resin composites.

Estudo comparativo da eficiência de corte de pontas diamantadas convencionais e de tecnologia de diamante CVD e da rugosidade de superfícies com o uso destes instrumentos / Comparative study of cutting efficiency of conventional diamond burs and CVD technology and surface roughness these instruments

Introdução - Atualmente, além da utilização das pontas diamantadas convencionais em alta-rotação, há outras formas para se realizar o desgaste dental. As pontas diamantadas fabricadas utilizando-se a tecnologia de diamante-CVD (chemical vapor deposition) acopladas em aparelhos de ultra-som são um exemplo destas alternativas. Os objetivos deste estudo foram avaliar a eficiência de corte (EC) das pontas diamantadas para ultra-som e compará-la com a apresentada pelas pontas diamantadas convencionais para alta-rotação e avaliar a rugosidade de superfície (RS) obtida após o uso dos dois tipos de pontas sobre espécimes confeccionados com resina composta e porcelana. Materiais e Métodos - Para a avaliação da EC foi utilizado o método gravimétrico. A RS dos corpos de prova foi aferida com um rugosímetro antes e após o desgaste com pontas diamantadas para acabamento. Resultados - Após análise estatística dos resultados, observou-se que as pontas em alta-rotação mostraram maior EC em relação às pontas em ultra-som, porém estas últimas apresentaram maior uniformidade nos desgastes, sem perda da eficiência ao longo dos testes. Em relação à RS, não houve diferenção estatisticamente significante nos valores de rugosidade nos corpos de prova de resina composta e porcelana, quando utilizada a ponta em alta-rotação. Já com a ponta em ultra-som foi observada uma menor RS das amostras em porcelana. Conclusões - Assim, pode-se concluir que as pontas diamantadas acopladas em ultra-som comportaram-se de maneira distinta das pontas em alta-rotação, observando-se a necessidade de mais estudos sobre os instrumentos diamantados para ultra-som, a fim de delimitar as melhores indicações e limitações da utilização destes instrumentos

Estudo comparativo da eficiência de corte de pontas diamantadas convencionais e de tecnologia de diamante CVD e da rugosidade de superfície com o uso destes instrumentos / Comparative study of cutting efficiency of conventional diamond burs and CVD technology and surface roughness with these instruments

Introdução - Atualmente, além da utilização das pontas diamantadas convencionais em alta rotação, há outras formas para se realizar o desgaste dental. As pontas diamantadas fabricadas utilizando-se a tecnologia de diamante-CVD (chemical vapor deposition) acopladas em aparelhos de ultra-som são um exemplo destas alternativas. Os objetivos deste estudo foram avaliar a eficiência de corte (EC) das pontas diamantadas para ultra-som e compará-la com a apresentada pelas pontas diamantadas convencionais para alta-rotação e avaliar a rugosidade de superfície (RS) obtida após o uso dos dois tipos de pontas sobre espécimes confeccionados com resina composta e porcelana. Materiais e Métodos - Para a avaliação da EC foi utilizado o método gravimétrico. A RS dos corpos de prova foi aferida com um rugosímetro antes e após o desgaste com pontas diamantadas para acabamento. Resultados - Após análise estatística dos resultados, observou-se que as pontas em alta-rotação mostraram maior EC em relação às pontas em ultra-som, porém estas últimas apresentaram maior uniformidade nos desgastes, sem perda da eficiência ao longo dos testes. Em relação à RS, não houve diferença estatisticamente significante nos valores de rugosidade nos corpos de prova de resina composta e porcelana, quando utilizada a ponta em alta-rotação. Já com a ponta em ultra-som foi observada uma menor RS das amostras em porcelana. Conclusões - Assim, pode-se concluir que as pontas diamantadas acopladas em ultra-som comportaram-se de maneira distinta das pontas em alta rotação,observando-se a necessidade de mais estudos sobre os instrumentos diamantados para ultra-som, a fim de delimitar as melhores indicações e limitações da utilização destes instrumentos.

Introduction - Nowadays, beyond the use of the conventional diamonds burs on high-speedt urbines, there are other ways to cut dental tissues, as an example the CVD (chemical vapor deposition) diamond burs connected on ultrasonic devices. The aim of this study were evaluate the cutting efficiency (CE) of CVD diamond burs in ultrasonic devices and to compare it with the conventional diamond burs. It was also evaluated the surface roughness (SR) of resin composite and porcelain samples after the use of finishing burs (conventional and CVD diamonds). Material and Methods - Gravimetrical method was used to examine the CE and for SR evaluation was used a profilometer. Results - After statistical analysis, data indicated that conventional diamond burs showed higher CE than CVD diamond burs. However CVD diamond burs showed a higher cutting uniformity during the tests. On the SR evaluation, no statistical difference was observed between resin composite and porcelain samples, when finishing diamond burs on high-speed turbine was used. Even tough with the finishing CVD diamond burs connected in the ultrasonic devices the SR was smaller on porcelain samples. Conclusions - Then, we concluded that CVD diamond burs connected on ultrasonic device had distinct performance than conventional diamond burs in high-speed turbines, showing that more studies are necessary to delimit the best indication and limitation of the use of these instruments.

Avaliação quantitativa e qualitativa de duas cerâmicas frente a diferentes tratamentos de superfície / Quantitative and qualitative evaluation of two ceramics in front of different surface treatments

A característica de superfície representa um fator importante na previsibilidade do comportamento dos materiais cerâmicos quanto ao desgaste. A rugosidade superficial de duas cerâmicas (Duceram Plus e Duceragold) foi avaliada através de dois métodos - análise quantitativa e qualitativa - após diferentes tratamentos. Foram confeccionados 36 corpos de prova de prova para a análise ao rugosímetro, e 24 corpos de prova para a análise ao MEV. Os resultados destas análises demonstraram o comportamento distinto entre os diferentes tratamentos. A análise com o rugosímetro demonstrou que a ação dos polidores EDENTA foi a mais efetiva para devolver lisura à superfície após a realização de desgaste com instrumento abrasivo diamantado rotatório. Todas as técnicas de polimento acarretaram em valores de rugosidade menores que os observados nos espécimes que foram submetidos apenas ao ôglazeõ. Entre as cerâmicas avaliadas, a Duceragold apresentou valores médios de rugosidade inferiores aos observados na porcelana Duceram Plus na maioria dos tratamentos pesquisados. Pela análise ao MEV não foi possível distinguir diferenças entre as cerâmicas ou entre os corpos de prova polidos ou submetidos apenas ao ôglazeõ

Quantitative analysis of dental porcelain surfaces following different treatments: correlation between parameters obtained by a surface profiling instrument.

This investigation compared, by quantitative analysis, the surface roughness of dental porcelain submitted to three different treatments (glaze, trimming and polishing), utilizing a surface profiling instrument. The parameters Ra (median roughness), Rz (median of the maximum profile heights of five sample lengths), Rpm (median of the maximum profile heights related to the median line of five sample lengths), Pc (peak count per centimeter) and Rpm/Rz (proportional parameter) were evaluated. In addition, the correlation between Ra and the other parameters was analyzed. Based on the results obtained, it was seen that the Ra parameter did not present any correlation with the other parameters in some of the situations evaluated. This demonstrates that complementation of the measurement with other parameters is always necessary, providing a better evaluation of the functional properties of a surface.

Anestesia odontologia: segurança e sucesso: parte 2 / Dental anesthesia: safety and success: part 2

O ato da anestesia na prática odontológica é hoje um procedimento extremamente seguro, o que pode ser constatado por meio das raríssimas notícias de acidentes graves, a despeito das inúmeras anestesias aplicadas diariamente pelos cirurgiöes-dentistas. No entanto, é importante a observaçäo de aspectos relacionados à técnica anestésica. esta segunda parte do estudo expressa os principais problemas relacionados à falha no controle da dor, mostrando alternativas eficazes no sentido de prover conforto aos pacientes nas situaçöes adversas