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A escolha da técnica restauradora desempenha papel fundamental na eficácia e duração de um tratamento reabilitador. O objetivo deste relato de caso foi descrever a utilização da técnica semidireta para a confecção de uma restauração em resina composta em um primeiro molar inferior. A paciente apresentava uma restauração insatisfatória no dente 36, que necessitava ser substituída devido à infiltração por cárie. Optou-se pela técnica semidireta devido à amplitude da cavidade, que envolvia estruturas de suporte, e pela combinação das vantagens das abordagens direta e indireta. O procedimento envolveu a remoção de tecido cariado, a aplicação de hidróxido de cálcio pasta, seguida da aplicação de uma fina camada de ionômero de vidro e, posteriormente, resina fluída para realizar o selamento dentinário. O preparo foi realizado seguindo os princípios necessários. O elemento em questão foi moldado com silicone de adição e o arco antagonista, com alginato. Ambos modelos foram vertidos com silicone para modelos semirrígidos e montados em oclusor de peças de brinquedo. A restauração semidireta foi confeccionada em resina composta Filtek Z350 XT, respeitando a anatomia do dente 36. Pigmentos foram utilizados para aprimorar detalhes estéticos. Após acabamento e polimento, a peça foi condicionada e cimentada com cimento dual Relyx Ultimate. Pode-se concluir que a abordagem restauradora por meio da técnica semidireta construída em modelo semirrígido é uma opção terapêutica conservadora e vantajosa para dentes com extensa destruição coronária. Essa técnica possibilita a restauração de forma eficaz, garantindo tanto a estética quanto a função adequada do dente afetado(AU)

The choice of restorative technique plays a fundamental role in the effectiveness and duration of rehabilitation treatment. The objective of this case report was to describe the use of the semi-direct technique to create a composite resin restoration in a lower first molar. The patient had an unsatisfactory restoration on tooth 36, which needed to be replaced due to cavity infiltration. The semi-direct technique was chosen due to the amplitude of the cavity, which involved support structures, and the combination of advantages of the direct and indirect approaches. The procedure involved the removal of carious tissue, and the application of calcium hydroxide paste, followed by the application of a thin layer of glass ionomer and, subsequently, fluid resin to seal the dentin. The preparation was carried out following the necessary principles. The element in question was molded with addition silicone and the antagonist arch was molded with alginate. Both models were poured with silicone for semi-rigid models and mounted on toy parts occluders. The semi-direct restoration was made in Filtek Z350 XT composite resin, respecting the anatomy of tooth 36. Pigments were used to improve aesthetic details. After finishing and polishing, the piece was conditioned and cemented with Relyx Ultimate dual cement. It can be concluded that the restorative approach using the semi-direct technique built on a semi-rigid model is a conservative and advantageous therapeutic option for teeth with extensive coronal destruction. This technique allows for effective restoration, ensuring both the aesthetics and adequate function of the affected tooth(AU)

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The objective of this article is to concisely review the main clinical techniques used to make the functional impression to manufacture a removable partial denture. Through this review, the dentist can develop his clinical knowledge.

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Tooth reduction guides allow clinicians to obtain the ideal space required for ceramic restorations. This case report describes a novel design (CAD) for an additive computer-aided manufactured (a-CAM) tooth reduction guide with channels that permitted access for the preparation and evaluation of the reduction with the same guide. The guide features innovative vertical and horizontal channels that permit comprehensive access for preparation and evaluation of the reduction with a periodontal probe, ensuring uniform tooth reduction and avoiding overpreparation. This approach was successfully applied to a female patient with non-carious lesions and white spot lesions, resulting in minimally invasive tooth preparations and hand-crafted laminate veneer restorations that met the patient's aesthetic demands while preserving tooth structure. Compared to traditional silicone reduction guides, this novel design offers greater flexibility, enabling clinicians to evaluate tooth reduction in all directions and providing a more comprehensive assessment. Overall, this 3D printed tooth reduction guide represents a significant advancement in dental restoration technology, offering clinicians a useful tool for achieving optimal outcomes with minimal tooth reduction. Future work is warranted to compare tooth reductions and preparation time for this guide to other 3D printed guides.

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Background: Resin composites undergo a certain degree of shrinkage when light-cured with different light sources available on the market, resulting in microleakage of dental restorations. The aim of the present study was to assess microleakage of class II restorations with bulk-fill resin composites cured with LED (light-emitting diode) and QTH (quartz tungsten-halogen light) units, both in cervical and occlusal areas of cavity preparations. Materials and Methods: In the present in vitro experimental study, a total of 30 human molar teeth were used, in which 60 class II cavities were prepared (mesial and distal) and restored with Filtek bulk fill resin composite. Restorations were equally distributed in 3 groups according to type of curing light: A, QTH (Litex 680A Dentamerica®); B, LED (Bluephase N® 3rd generation); and C, LED (Valo® 3rd generation). Each group was further subdivided into subgroups 1 and 2 according to IV-A or IV-B resin composite color. Restored teeth were subjected to 20,000 thermal cycles between 5° and 55 °C, then immersed in 1M silver nitrate solution for 24 h. Subsequently, the teeth were sectioned mesiodistally to obtain samples for observation under stereomicroscope in order to determine microleakage degree. Kruskal-Wallis H and Mann-Whitney U statistical tests were applied with a significance level of 5% (p < 0.05). Results: No statistically significant differences were found in the degree of microleakage of bulk-fill resin composites light-cured with LED and QTH units for both occlusal (p > 0.05) and cervical areas (p > 0.05). Additionally, no significant differences were found when comparing microleakage between occlusal and cervical areas (p > 0.05), regardless of lamp type. In addition, significant differences in microleakage degree were found between bulk-fill resins with IV-A and IV-B shades when they were light-cured with QTH at cervical level (p = 0.023). However, there were no significant differences when comparing these bulk-fill resin composite shades at occlusal level with LED (p > 0.05) and QTH (p > 0.05) units. Conclusions: Class II restorations with bulk-fill resin composite in IV-A and IV-B shades light-cured with third generation LED lamp and QTH showed no significant differences in microleakage when compared in both occlusal and cervical areas. On the other hand, significantly more microleakage was found at the cervical level when a darker shade of resin composite was used and light-cured with the QTH unit.

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Objetivo: Analizar las distintas alternativas de tratamiento basadas en Ortopedia Funcional y Mecánica, su efecto a nivel esqueletal, sus beneficios. Método: Revisión bibliográfica. Resultados: Se seleccionaron 15 artículos de un universo de 45, por cuanto eran los que tenían relación directa con el tema de investigación. Conclusión: Se ha logrado identificar las distintas alternativas de tratamiento con ortopedia funcional o mecánica que se pueden utilizar para el tratamiento de la Clase II esqueletal, corroboradas con resultados que evidencian Su efectividad tanto en los cambios craneofaciales, de tejidos blandos y dentales obtenidos al final de la terapéutica, los autores recomiendan la correcta evaluación de los pacientes, antes de determinar la aparatología a utilizar así cómo aprovechar los estadios tempranos de maduración y crecimiento para que los cambios en el patrón esqueletal sean más representativos, efectivos y alcancen el objetivo de mejorar la relación maxilo-mandibular.

Objective: To analyze the different treatment alternatives based on Functional and Mechanical Orthopedics, their effect at skeletal level, their benefits. Method: Bibliographic review. Results: 15 articles were selected from a universe of 45, as they were those directly related to the research topic. Conclusions: We have been able to identify the different treatment alternatives with functional or mechanical orthopedics that can be used for the treatment of skeletal Class II, corroborated with results that show their effectiveness in craniofacial, soft tissue and dental changes obtained at the end of the therapy, the authors recommend the correct evaluation of the patients before determining the appliances to be used, as well as taking advantage of the early stages of maturation and growth so that the changes in the skeletal pattern are more representative, effective and achieve the objective of improving the maxillomandibular relationship.

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BACKGROUND: The contraction presented by resin composites causes an increase in stress at the tooth-resin interface, causing micro-gaps that allow microleakage. This study aims to evaluate the degree of in vitro marginal microleakage in class II restorations with two bulk fill resin composites compared to a conventional nanohybrid resin composite. METHODS: The present study was an in vitro experimental design. A total of 30 standardized class II cavities were prepared in 15 human molars (mesially and distally). These cavities were later distributed in 3 groups according to the type of resin. Groups A and B were restored with bulk fill resin composites (Filtek-3 M/ESPE and Tetric N-Ceram-Ivoclar/Vivadent respectively) in a single increment of 4 mm. Group C was restored with the Filtek Z350 XT - 3 M/ESPE resin composite and two increments of 2 mm. Later, the restorations were subjected to 10,000 thermocycles between 5 °C to 55 °C and immersed in a silver nitrate solution (1 M for 24 h). The crowns were then sectioned mesiodistally and observed under the stereomicroscope to determine the degree of marginal microleakage at the occlusal and cervical areas. The results were analyzed with the Kruskal-Wallis and the Mann-Whitney U statistical tests. RESULTS: There were no statistically significant differences regarding the degree of microleakage between the three types of resin composites in the occlusal and cervical areas (p > 0.05). Similarly, there were no significant differences after comparing each resin type in its occlusal and cervical area (p > 0.05). CONCLUSION: Filtek Bulk Fill and Tetric N-Ceram Bulk Fill resin composites showed no statistically significant differences with the conventional nanohybrid resin composite Filtek Z350XT at both occlusal and cervical areas.

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Abstract The aim of this study was to evaluate the survival of laminate veneers constructed using a recent polymer-infiltrated ceramic network material following the aesthetic pre-evaluative temporary (APT) technique of tooth preparation in comparison to traditional technique. Six patients received 54 laminate veneers. They were divided into two equal groups (n=27) according to the technique of tooth preparation: group T: traditional technique and group A: aesthetic pre-evaluative temporary technique. VITA ENAMIC material was used for CAD/CAM construction of laminate veneers. Cementation was performed using a light cured resin cement. The laminate veneers were evaluated at baseline, after 3, 6 and 12 months according to the modified United States Public Health Service (USPHS) criteriea. The data was collected, tabulated and statistically analyzed. Secondary caries, endodontic complications, cracks and loss of retention were not noted in any laminate veneer. Extensive fractures were not detected in both study groups through the study period. There was a statistically significant decrease of color match criteria between the two groups at the 6 and 12 months recalls. Based on this study, both preparation techniques resulted in successful clinical performance. After 12 months, all the veneers in both groups showed no post-operative sensitivity and all patients were highly satisfied regarding their veneers. However, there was a deterioration in color match criteria through the study period in both study groups.

Resumo O objetivo deste estudo foi avaliar a sobrevivência de facetas laminadas construídas utilizando um material recente de rede de cerâmica impregnada de polímero, seguindo a técnica estética pré-avaliadora temporária (APT) de preparação de dentes em comparação com a técnica tradicional. Seis pacientes receberam 54 facetas de laminados. Foram divididos em dois grupos iguais (n=27) de acordo com a técnica de preparação do dente: grupo T: técnica tradicional e grupo A: técnica temporária pré-avaliativa estética. O material VITA ENAMIC foi utilizado para a construção de facetas de CAD/CAM de laminados. A cimentação foi realizada utilizando um cimento de resina fotopolimerizável. Os laminados foram avaliados na linha de base, após 3, 6 e 12 meses de acordo com os critérios modificados do Serviço de Saúde Pública dos Estados Unidos (USPHS). Os dados foram recolhidos, tabulados e analisados estatisticamente. Cáries secundárias, complicações endodônticas, fissuras e perda de retenção não foram observadas em nenhuma faceta laminada. Não foram detectadas fraturas extensas em ambos os grupos de estudo durante o período do estudo. Verificou-se uma diminuição estatisticamente significativa dos critérios de correspondência de cor entre os dois grupos nos 6 e 12 meses. Com base neste estudo, ambas as técnicas de preparação resultaram num desempenho clínico bem sucedido. Após 12 meses, todos os laminados de ambos os grupos não mostraram qualquer sensibilidade pós-operatória e todos os pacientes ficaram altamente satisfeitos com os seus laminados. No entanto, houve uma deterioração dos critérios de correspondência de cor durante o período de estudo em ambos os grupos de estudo.

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Resumen Antecedentes. La resistencia a la fractura de las coronas puede tener influencia en su ocurrencia, de acuerdo con el método de fabricación usado, ya sea análogamente o por medio de tecnología Cad-Cam. Objetivo. Comparar la resistencia a la fractura de las coronas individuales realizadas por dos métodos de fabricación, bajo diseño asistido por ordenador y fabricación computarizada (CAD-CAM) e inyectadas. Método. Estudio in vitro. Tamaño de la muestra 20 coronas en dos grupos: 10 coronas bajo tecnología CAD-CAM y 10 coronas inyectadas. Fueron sometidas a cargas compresivas en una máquina de ensayos universal, con una velocidad de 1mm/min y una carga de celda de 5kN hasta obtener la fractura máxima de estas. Los datos se analizaron estadísticamente utilizando las pruebas Shapiro Wilk, Mann Whitney p=0,05. Resultados. Las coronas fabricadas por Cad-Cam obtuvieron un mínimo de 602,5 Newton y un máximo de 1093 Newton, mientras que las coronas fabricadas análogamente obtuvieron un mínimo de 525,2 Newton y un máximo de 1773 Newton en el experimento con la máquina de ensayo universal para lograr su fractura. Se obtuvo una diferencia significativa en la prueba de resistencia a la factura entre ambos métodos de fabricación (p <0,001). Conclusión. Las coronas de Disilicato de litio Prensadas obtuvieron una mayor resistencia a la fractura que las coronas fabricadas via CAD-CAM.

Abstract Background. The fracture resistance of the crowns may have an influence on their appearance, according to the method of making them, either analogously or by means of Cad-Cam technology. Objective. To compare the resistance to the fracture of the individual crowns made by two manufacturing methods, under computer-aided design and computerized manufacturing (CAD-CAM) and injected. Methods. In vitro study. Sample size 20 crowns in two groups: 10 crowns using CAD-CAM technology and 10 crowns injected. Crowns were subjected to compressive loads in a universal testing machine, with a speed of 1mm / min and a cell load of 5kN until obtaining the maximum bill for these. Data were statistically analyzed using the Shapiro Wilk tests, Mann Whitney p = 0.05. Results. Crowns manufactured by Cad-Cam obtained a minimum of 602.5 Newton and a maximum of 1093 Newton, while the crowns manufactured analogously obtained a minimum of 525.2 Newton and a maximum of 1773 Newton in the experiment with the machine Universal test to achieve their fracture. A significant difference was obtained in the invoice resistance test between both manufacturing methods (p <0.001). Conclusion. Pressed Lithium Disilicate crowns obtained higher fracture resistance than crowns under design and manufacturing by computer (CAD-CAM).

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This study evaluated the polymerization shrinkage stress of three tooth preparation designs for indirect ceramic overlay by finite element analysis: isthmus preparation (IST); without isthmus preparation (wIST); and non-retentive preparation (nRET). The models were created based in prepared dental typodonts and were digitally impressed with an intraoral scanner. The interfaces in all models were considered perfectly bonded and all materials were considered homogeneous, linear, and isotropic. The polymerization shrinkage of the cement layer (100 µm) was simulated and evaluated by maximum principal stress criteria. The stress peaks followed this sequence: restoration = IST (13.4 MPa) > wIST (9.3 MPa) > nRET (9 MPa); cement layer = IST (16.9 MPa) > wIST (12.6 MPa) > nRET (10-7.5 MPa); and teeth = IST (10.7 MPa) > wIST (10.5 MPa) > (9 MPa). For the cement layer, the non-retentive preparation (nRET) had the lowest shrinkage stress from all the groups, obtaining a more homogeneous stress distribution on the cement surface. Regarding the abutment teeth, the IST generated a higher shrinkage stress area on the dental structure, concentrating higher stress magnitude at the axiopulpar and axiogingival angles. Non-retentive preparation seems to reduce polymerization shrinkage stress.

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Objective: The purpose of this in vitro study is to evaluate the effect of four finish line configurations and two cement types on the fracture resistance of zirconia copings. Material and Methods: Forty yttrium tetragonal zirconia polycrystals copings were manufactured on epoxy resin dies with four preparation designs: knife edge, chamfer, deep chamfer 0.5, 1 mm and shoulder 1 mm. The copings were cemented with two cement types (glass ionomer and resin cement); (n = 5). Two strain gauges were attached on each coping before they were vertically loaded till fracture with a universal testing machine. Data were analyzed by 2-way analysis of variance ANOVA (p < .05). Fractured specimens were examined for mode of failure with digital microscope. Results: Knife edge showed the highest mean fracture resistance (987.04 ± 94.18) followed by Chamfer (883.28 ± 205.42) followed by Shoulder (828.64 ± 227.79) and finally Deep chamfer finish line (767.66 ± 207.09) with no statistically significant difference. Resin cemented copings had higher mean Fracture resistance (911.76 ± 167.95) than glass ionomer cemented copings (821.55 ± 224.24) with no statistically significant difference. Knife edge had the highest strain mean values on the buccal (374.04 ± 195.43) and lingual (235.80 ± 103.46) surface. Shoulder finish line showed the lowest mean strain values on the buccal (127.47 ± 40.32) and lingual (68.35 ± 80.68) with no statistically significant difference. Resin cemented copings had higher buccal (295.05 ± 167.92) and lingual (197.38 ± 99.85) mean strain values than glass ionomer copings (149.14 ± 60.94) and (90.27 ± 55.62) with no statistically significant difference. Conclusion: Vertical knife edge finish line is a promising alternative and either adhesive or conventional cementation can be used with zirconia copings (AU)

Objetivo: O objetivo deste estudo in vitro é avaliar o efeito de quatro configurações de términos cervicais e dois tipos de cimentos na resistência à fratura de copings de zircônia. Material e Métodos: Quarenta copings de zircônia tetragonal policristalina estabilizada por ítrio foram confeccionados em matrizes de resina epóxi com quatro tipos de términos cervicais: lâmina de faca, chanfro, chanfro largo 0,5, 1 mm e ombro 1 mm. Os copings foram cimentados com dois tipos de cimento (ionômero de vidro e cimento resinoso); (n = 5). Dois extensômetros foram fixados em cada coping antes de serem carregados verticalmente até a fratura com uma máquina de teste universal. Os dados foram analisados por análise de variância ANOVA 2 fatores (p < 0,05). Os espécimes fraturados foram examinados quanto ao modo de falha com microscópio digital. Resultados: A Lâmina de faca apresentou a maior média de resistência à fratura (987,04 ± 94,18) seguida pelo Chanfro (883,28 ± 205,42), pelo Ombro (828,64 ± 227,79) e finalmente o Chanfro largo (767,66 ± 207,09), sem diferença estatisticamente significativa. Os copings cimentados com cimento resinoso apresentaram maior média de resistência à fratura (911,76 ± 167,95) em relação aos copings cimentados com ionômero de vidro (821,55 ± 224,24), sem diferença estatisticamente significativa. A lâmina de faca apresentou os maiores valores médios de deformação na superfície vestibular (374,04 ± 195,43) e lingual (235,80 ± 103,46). O término em ombro apresentou os menores valores médios de deformação na superfície vestibular (127,47 ± 40,32) e lingual (68,35 ± 80,68), sem diferença estatisticamente significativa. Os copings cimentados com resina apresentaram maiores valores médios de deformação na superfície vestibular (295,05 ± 167,92) e lingual (197,38 ± 99,85) do que os copings cimentados com ionômero de vidro (149,14 ± 60,94) e (90,27 ± 55,62), sem diferença estatisticamente significativa. Conclusão: O término cervical em lâmina de faca é uma alternativa promissora e a cimentação adesiva ou convencional pode ser usada na cimentação de copings de zircônia. (AU)

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El objetivo de esta investigación fue analizar los ángulos de convergencia en preparaciones dentarias para coronas realizadas en tipodontos, por estudiantes de décimo semestre de Odontología Unach. Las preparaciones dentales para coronas poseen características de retención y resistencia, principios fundamentales que ofrecen éxito y longevidad de la corona definitiva. Varios investigadores a nivel mundial han desarrollado diversos métodos para evaluar los ángulos de convergencia de las preparaciones extracoronarias; sin embargo, en nuestro medio, no existen estudios acerca de la medición de estos ángulos. Esta investigación fue de carácter experimental, transversal y observacional, se obtuvieron 32 preparaciones dentarias para coronas de recubrimiento completo, cada estudiante tuvo 60 minutos para tallar dos preparaciones dentarias en simuladores clínicos. Los tipodontos fueron escaneados y digitalizados mediante el escáner CAD-CAM Ceramill Database versión 1.0 año 2010 del Laboratorio "BrothersDent" para producir imágenes tridimensionales. El software iTero midió los ángulos vestíbulo-lingual (VL) y mesio-distal (MD) de cada preparación. Los ángulos más pequeño y más grande observados fueron 3.1° y 102.5° para molares mandibulares. El promedio del ángulo VL para dientes anteriores fue 40,38 ±4,38° en varones y 36,97 ±3,95° en mujeres y el promedio del ángulo MD fue 44,68 ±5,51° en varones y 40,08 ±3,99° en mujeres. Para dientes posteriores el promedio VL fue 27,46 ±7,82° en varones y 40,98 ±4,63° en mujeres; y el promedio del ángulo MD fue 40,73 ±5,95° en varones y 50,62 ±7,00° en mujeres. En conclusión, los ángulos de convergencia logrados por estudiantes fueron mayores que los ideales recomendados según Shillingburg.

This research aimed to analyze the angles of convergence in dental preparations for crowns performed on typodont, by 10th semester students of school of dentistry, UNACH. Dental preparations for crowns have retention and resistance characteristics, fundamental principles that offer success and longevity of the final crown. Various researchers worldwide have developed various methods to evaluate the convergence angles of extra coronary preparations; however, in our context, there are no studies on the measurement of these angles. This research was experimental, cross-sectional and observational, 32 dental preparations were obtained for fully covered crowns, each student had 60 minutes to carve two dental preparations in clinical simulators. The typodonts were scanned and digitized using the scanner CAD-CAM Ceramill Database version 1.0 - 2010 of "BrothersDent" Laboratory in order to produce three-dimensional images. The iTero software measured the vestibule-lingual (VL) and mesio-distal (MD) angles of each preparation. The smallest and largest angles observed were 3.1 ° and 102.5 ° for mandibular molars. The mean VL angle for anterior teeth was 40.38 ± 4.38 ° in males and 36.97 ± 3.95 ° in females, and the mean MD angle was 44.68 ± 5.51 ° in males and 40, 08 ± 3.99 ° in women. For posterior teeth the average VL was 27.46 ± 7.82 ° in men and 40.98 ± 4.63 ° in women; and the mean MD angle was 40.73 ± 5.95 ° in men and 50.62 ± 7.00 ° in women. In conclusion, the convergence angles achieved by students were greater than the recommended ideals according to Shillingburg.

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O presente estudo avaliou a qualidade dos preparos para coroas totais confeccionadas em zircônia por sistemas CAD/CAM (computer aided design/computer aided manufacturing). Atualmente, os materiais cerâmicos são os preferidos para restaurações indiretas, por possibilitarem um trabalho resistente e de excelente estética. Entretanto, observa-se que há necessidade de adequação dos preparos cavitários para as restaurações CAD/CAM, em relação a três fatores: o tipo de cimentação, o tipo de material a ser fresado e as dimensões das ferramentas de fresagem. O presente estudo transversal avaliou 357 preparos para coroa total em zircônia, por meio de imagens digitais obtidas em escâner de cinco laboratórios de prótese dentária do Rio de Janeiro no período de 01/10/2018 a 31/11/2018. Foram quantificados os possíveis erros de preparos cavitários em função das limitações de diâmetro das ferramentas de fresagem dos sistemas Ceramill (Amann Girrbach) dos laboratórios incluídos. As imagens dos preparos foram identificadas e relacionadas em um documento Excel e, após realizado o cálculo amostral, uma amostra representativa da população foi selecionada aleatoriamente. Dois examinadores conjuntamente avaliaram se a convergência para oclusal, as áreas retentivas, a borda incisal aguda ou a redução oclusal, a quantidade de desgaste e o término cervical estavam adequados. Após a avaliação, menos de 1% dos preparos atenderam adequadamente a todos os parâmetros, enquanto aproximadamente 20% não atenderam a nenhum. O parâmetro menos atendido foi o término cervical, em 94,1% do total de casos. A conclusão é que os preparos para zircônia CAD/CAM avaliados no estudo não atenderam aos parâmetros estipulados neste estudos.(AU)

The present study evaluated the quality of CAD/CAM (computer aided design/computer aided manufacturing) zirconia-based full crown dental preparations. Ceramics are the most used materials for indirect dental restorations nowadays, since they make a final product both resistant and with excellent in esthetics. However, a need to adapt the dental preparation design for CAD/CAM restorations has been observed, especially regarding three factors: the type of bonding material, the type of material to be milled and the dimensions of the milling burs used in the milling machines. The present transversal study evaluated 357 zirconia-based full crown dental preparations, through digital images obtained with the scanners of five laboratories in Rio de Janeiro between 01/10/2018 and 31/11/2018. The possible errors in the dental preparation process, given the limitations in diameter of the milling burs of their Ceramill (Amann Girrbach) CAD/CAM systems, were quantified. The images of the preparations were identified and listed in an Excel file and, after a sampling process, a representative sample from the population was randomly selected. Two researchers together evaluated if the occlusal convergency, the retentive areas, the sharp incisal border or anatomic occlusal reduction, the amount of reduction and the cervical finish line were adequate. After an statistical analysis, less than 1% of the preparations followed all parameters adequately, while approximately 20% followed none of them. The parameter less followed was the cervical finish line, inadequate in 94,1% of all cases. The conclusion is that the preparations for zirconia-based CAD/CAM full crowns evaluated in this study did not follow the stablished parameters of this study.(AU)

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Las nuevas tecnologías digitalizadas han permitido migrar de la técnica de cera perdida colada por centrifugación (CPC) a la fabricación sustractiva por CAD/CAM como la técnica de fresado de bloque blando (SMB). Objetivo: El propósito de este estudio fue comparar las adaptaciones marginales e internas en cofias metálicas de Co-Cr sobre dos líneas de terminación: chamfer y bisel confeccionadas mediante dos técnicas: CPC y SMB. Material y Métodos: Se confeccionaron dos modelos maestros de Co-Cr con terminación chamfer y bisel, se formaron 4 grupos de estudio y se fabricaron 13 cofias por grupo. Para la evaluación de las adaptaciones marginal e interna se usó el método de la réplica en silicona, luego con un estéreo microscopio se evaluó las discrepancias marginales e internas. Resultados: Para la discrepancia marginal entre las dos técnicas, para la terminación bisel sólo se observó diferencias estadísticamente significativas (p<0,05) en los puntos A1 y A2 y en la terminación chamfer se observó diferencias estadísticamente significativas (p<0,05) en los puntos A1 y F1. En la adaptación interna comparando ambas técnicas en la terminación bisel se obtuvo diferencias estadísticamente significativas (p<0,05) en los puntos E1, E2, D1, C2 y D2. En la terminación chamfer los resultados mostraron diferencias estadísticamente significativas (p<0,05) en todos los puntos. Conclusiones: Las cofias que presentaron mejor adaptación marginal fueron las confeccionadas por SMB con la línea de terminación chamfer, en la línea de terminación bisel no se pudo concluir cuál de las dos técnicas es mejor en adaptación marginal. Las que presentaron mejor adaptación interna en ambas líneas de terminación, en la zona axial fueron las cofias realizadas mediante la técnica CPC y en la zona oclusal presentaron mejor adaptación interna el SMB.

The new digitized technologies have allowed to migrate from the technique of lost cast wax by centrifugation (CPC) to the subtractive manufacturing by CAD / CAM as the technique of soft-block milling (SMB). Objective: The purpose of this study was to compare the marginal and internal adaptations in metal Co-Cr copes on two termination lines: chamfer and bevel made by two techniques: CPC and SMB. Material and Methods: Two Co-Cr master models with chamfer and bevel termination were made, 4 study groups were formed and 13 copings were made per group. For the evaluation of the marginal and internal adaptations the replication method was used in silicone, then with a stereomicroscope the marginal and internal discrepancies were evaluated. Results: For the marginal discrepancy between the two techniques, only statistically significant differences were observed for the bevel termination (p <0.05) in points A1 and A2 and in the chamfer termination statistically significant differences were observed (p <0.05) in points A1 and F1. In the internal adaptation comparing both techniques in the bevel termination, statistically significant differences were obtained (p <0.05) in points E1, E2, D1, C2 y D2. And in the chamfer termination, the results showed statistically significant differences (p <0.05) in all the points. Conclusions: The copes that presented better marginal adaptation were those made by SMB with the chamfer termination line, in the bevel termination line it was not possible to conclude which of the two techniques is better in marginal adaptation. The ones that presented better internal adaptation in both lines of termination, in the axial zone were the copings made using the CPC technique and in the occlusal area the SMB had better internal adaptation.

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Purpose: De-bonding strength of ceramic veneers by laser use needs to be evaluated in detail. The aim of this study, is to determine the contribution of ceramic thickness and cementing agents to the de-bonding strength of ceramic veneers using Er,Cr:YSGG laser. Methods: A total of 120 maxillary central incisors specimens were randomly divided into twelve groups on the basis of disc thickness, cementing agent, and Er,Cr:YSGG laser use. Under laboratory conditions, 120 IPS Empress II system discs 0.5mm, 1mm, and 2mm in thickness were applied to the tooth surfaces, for laser use. An Er,Cr:YSGG laser system was applied to the central surface of the IPS Empress II discs on specimens in all laser groups (Groups 1,3,5,7,9,11). Then the shear bond strength (SBS) for all specimens were tested with a testing machine at a speed of 0.5mm/min. The SBS values were considered as the de-bonding strength. Results: The mean de-bonding strength values for Groups 9 and 11 (0,5 mm disc thickness + laser application) have the lowest median load (0.000 N), while Group 4 (2mm disc thickness + no laser) has the highest median load (573.885 N). The de-bonding strengths of all the groups without laser application were higher than those of all groups with laser use. When laser is applied, the mean de-bonding strength decreases with decreasing disc thickness, and it reaches zero at 0.5mm thickness of discs cemented by self- or total-etch adhesives. Conclusions: The de-bonding strength decreases with laser use, and decreasing disc thickness. In the absence of laser, the mean de-bonding values of discs cemented by a total etch adhesive system are always higher than those of discs cemented with a self-etch adhesive system. Without any extra load, all 0.5mm thick discs were dislodged from teeth while applying or testing the laser.

Propósito: La resistencia de desunión de las carillas de cerámica mediante el uso del láser debe evaluarse en detalle. El objetivo de este estudio es determinar la contribución del espesor de la cerámica y los agentes de cementación a la resistencia de desunión de las carillas de cerámica utilizando el láser Er, Cr: YSGG. Métodos: Un total de 120 incisivos centrales maxilares se dividieron al azar en doce grupos según el grosor del disco, el agente de cementación y el uso del láser Er, Cr: YSGG. En condiciones de laboratorio, se aplicaron en las superficies de los dientes 120 discos del sistema IPS Empress II de 0,5mm, 1mm y 2mm de grosor, para uso con láser. Se aplicó un sistema láser Er, Cr: YSGG a la superficie central de los discos IPS Empress II en muestras de todos los grupos de láser (Grupos 1,3,5,7,9,11). Luego, la resistencia de la unión al cizallamiento (SBS) para todas las muestras se probó con una máquina de prueba a una velocidad de 0.5mm/min. Los valores de SBS se consideraron como la fuerza de desunión. Resultados: Los valores medios de resistencia de desunión para los Grupos 9 y 11 (espesor de disco de 0,5mm + aplicación de láser) demostró la carga media más baja (0,000 N), mientras que el Grupo 4 (espesor de disco de 2 mm + sin láser) tuvo la carga media más alta (573.885 N). Las fuerzas de desunión de todos los grupos sin aplicación de láser fueron superiores a las de todos los grupos con uso de láser. Cuando se aplica el láser, la fuerza media de desunión disminuye al disminuir el grosor del disco, y llega a cero con el grosor de 0,5mm de los discos cementados, para ambos adhesivos de grabado. Conclusiones: la fuerza de desunión disminuye con el uso del láser y disminuye con el grosor del disco. En ausencia de láser, los valores medios de desunión de los discos cementados con un sistema de adhesivo de grabado total son siempre más altos que los de los discos cementados con un sistema de adhesivo de autograbado. Sin ninguna carga adicional, todos los discos de 0,5mm de grosor se desprendieron de los dientes al aplicar el láser.

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Aim: it was to use tridimensional finite element analysis (FEA) to analyze the effect of height and angulation of prosthetic preparations on the distribution of stresses for lithium disilicate prosthetic crowns, the underlying resin cement, and the prosthetic preparation of a superior central incisor. Methods: a CAD modeling software, SolidWorks 2013, was used to generate three-dimensional virtual models comprising the dimensions of the preparation parameters. Three angles (6, 12 and 16 degrees) were simulated on the prepared walls and two wall heights were utilized (4 and 5 mm), for a total of six model groups according to the height and angulation of the walls. A vertical line in the Y-axis was used as a reference for determining the degrees of convergence (inclination of the preparations). The chamfer finish and preparation width were standardized for all groups. Results: the 4 mm preparations behaved more appropriately when the axial wall convergence was approximately 6 degrees. The 5 mm preparations required 12 degrees of angulation. In relation to resin cement, there was better stress distribution when the angle of incisal convergence was between 6 and 12 degrees. An increase to 16 degrees led to a considerable increase in peak stress at the preparation margin. Conclusion: it was concluded that the convergence of the axial walls of coronal preparations with 4 and 5 mm heights should be 6 and 12 degrees, respectively, to avoid high tension spikes in the underlying resin cement

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Introducción: el tratamiento endodóntico es muy solicitado para preservar las piezas dentales, así como la utilización de pernos de fibra cuando el remanente coronario no es el adecuado para recibir una prótesis coronaria, permitiendo de esta manera reconstruir el muñón dental para la posterior colocación de la restauración definitiva. Objetivo: identificar tanto el tratamiento de superficie de pernos de fibra como el irrigante radicular idóneos para conseguir una cementación adecuada; así como conocer cuál es el tratamiento de superficie que produce menos desintegración de las fibras del perno de fibra. Materiales y métodos: se incluyeron 47 artículos publicados en inglés, durante los últimos 20 años, teniendo en cuenta que los mismos se obtuvieron hasta octubre del 2018. Conclusiones: previa la cementación de pernos sean estos de fibra o de cuarzo es indispensable realizar tratamiento de superficie para así mejorar la adhesión, estos pueden ser químicos o físicos, los que ofrecen mejor resultado sin alterar de manera significativa la estructura del mismo es el enarenado con partículas de diamante sintéticas de 1-3 µm seguido de silanización y dentro de los químicos H2O2 al 10% por 1 min seguido de silano. Para obtener mejores resultados se debe accionar el silano a una temperatura de 80°C. En cuanto a protocolos de irrigación depende del sistema de cementación que se vaya a emplear EDTA 18% + Hipoclorito de sodio al 5,25% o EDTA 18% + clorhexidina al 2% cuando se va emplear un cemento autoadhesivo y NaOCl al 11% cuando se utilice el acondicionamiento ácido de lavado y secado.

Introduction: nowadays the aim is to keep the dental organ in function as long as possible, in many cases the endodontic treatment is used to preserve the dental pieces; and the use of fiber post when the coronary remnant is not adequate to receive a crown prosthesis, allowing us in these cases rebuilt the thoot for the subsequent placement of the final restoration. Objective: to identify wich is the better surface treatment of fiber post and the root irrigator for adequate cementation; as well as know, which is the surface treatment that produces less fibers' disintegration of the fiber post. Materials and methods: it were included 47 articles published in English, during the last 20 years, considering that they were obtained until October 2018. Conclusions: Before posts cementation are these fiber or quartz it is indispensable to carry out the surface pretreatment to increase adhesion, the same ones that can be chemical or physical within these that offer the best result it is the sanded with particles of diamond synthetic of 1-3 µm followed by silanization and with 10% H2O2 for 1min followed by silane. For better results silane must be dryed at a temperature of 80 °C. And for irrigation protocols depends of the cementing system to be used EDTA 18% + sodium hypochlorite 5.25% or EDTA 18% + 2% chlorhexidine when a self-adhesive cement is to be used and 11% NaOCl when washing and drying acid conditioning is used.

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Paciente apresentava dentes 12 e 22 com formatos conoides e restaurações insatisfatórias, os demais dentes eram hígidos e apresentavam formato natural. Assim, o tratamento adotado foi a remoção das restaurações insatisfatórias associada a preparos minimamente invasivo e laminados confeccionados com cerâmica feldspática nos dentes 12 e 22. As restaurações em resina composta apresentavam proporções e anatomias adequadas, adotando-as como guia para os preparos dentais. Inicialmente, foram utilizadas brocas diamantadas em alta rotação para o preparo inicial e, em seguida, pontas ultrassônicas para remoção da resina composta e finalização dos preparos. Realizou-se a moldagem com silicone de adição e os laminados cerâmicos foram confeccionados pela técnica da aplicação sobre troquel refratário. Clinicamente, realizou-se a prova das cerâmicas e a cimentação após aprovação da paciente. A fase da cimentação seguiu o seguinte protocolo: isolamento absoluto, profilaxia dos preparos dentais, condicionamento ácido e aplicação de sistema adesivo. As superfícies internas dos laminados foram condicionadas e então aplicados silano e sistema adesivo. A resina composta foi aquecida e inserida na superfície dos laminados, que foram posicionados sobre os preparos dentais com o auxílio do instrumento ultrassônico até a sua posição final. Após a remoção dos excessos, realizou-se a fotopolimerização do conjunto, polimento da interface adesiva, ajustes oclusais e polimentos finais. O caso foi realizado com acompanhamento clínico e radiográfico de 12 meses, e favorável prognóstico. (AU)

This patient had conoid teeth at the 12 and 22 positions with unsatisfactory restorations. The remaining teeth were healthy. Thus, the treatment adopted was the removal of the restorations associated with minimally invasive preparations and feldspathic ceramics on tooth numbers 12 and 22. The restorations in composite resin had adequate proportions and anatomy, adopting them as a guide for dental preparations. Initially, diamond burs were used in high-rotation speed for the initial preparation, and then ultrasonic tips for removal of the composite resin and finalization. An impression was carried out with addition silicone and the ceramic laminates made using the refractory die technique. Clinically, the ceramics were tried-in and cemented after patient approval. The cementation phase was made as the following: rubber dam isolation, prophylaxis, acid etching and adhesive application. The inner laminate surfaces were conditioned, silanated, and received the adhesive system. The composite resin was heated and inserted into the laminates, which were placed on the dental preparations with the the ultrasonic instrument to their final position. After excess removal, photactivation was made and the adhesive interface was polished, followed by occlusal adjustments and fi nal polishing. After clinical and radiographic follow-up of 12 months, a favorable prognosis was observed. (AU)

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Este trabalho teve o propósito de discutir, através de uma revisão da literatura, as vantagens e os obstáculos encontrados no preparo protético em prótese fixa utilizando pontas ultrassônicas, em detrimento das pontas diamantadas convencionais em alta rotação. As brocas diamantadas convencionais são tradicionalmente utilizadas em preparos protéticos e estendem-se para outras áreas da Odontologia. Pelo fato de apresentarem algumas limitações, como curta durabilidade, desconforto ao paciente, perda progressiva de partículas de diamante e produção de calor mesmo com a irrigação, pontas diamantadas ultrassônicas obtidas através da deposição química na fase de vapor (Chemical Vapor Deposition - CVD) foram desenvolvidas. Com base na literatura revisada, as pontas diamantadas acopladas ao ultrassom trazem benefícios ao preparo protético, como menor desgaste da estrutura dentária, maior remoção de smear layer, menor produção de ruído, calor e pressão, além de maior conforto ao paciente. No entanto, a lenta ação de corte e a pouca disponibilidade das pontas no mercado reforçam a necessidade de maiores estudos sobre os reais benefícios e vantagens que essa técnica possui em relação à técnica tradicional, em alta rotação.

This paper aims to discuss, through a literature review, the advantages and drawbacks regarding the abutment preparation with ultra-sonic tips compared to traditional high-speed burs for fixed prostheses. The conventional diamond burs have been used for and also involves other areas in the dental fi eld. Due to their limitations, such as short durability, patient discomfort, progressive loss of diamond particles and heat production even under copious irrigation, diamond ultrasonic tips were developed through the CVD technology. Based on the reviewed literature, the ultrasonic tools present more tooth conservation, greater smear layer removal, less noise, heat, and applied pressure, in addition to more patient comfort. However, its reduced cutting velocity and the fewer number of tips in the market reinforce the need for more studies on the real benefits of this technique compared to the traditional high-speed abutment preparation.

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Unsatisfactory anatomical shape of anterior tooth promotes disharmony in the smile esthetics. The conservative dental esthetic reestablishment treatments has been improved and evaluated with the development of adhesive materials. The adhesive dentistry allowed minimally invasive preparation through direct treatments with composite resin and indirect ceramic laminates veneers. These two treatments methods present advantages and disadvantages. The aim of this manuscript is to describe two clinical reports and compare alternatives to rehabilitate the smile esthetic appearance by direct and indirect minimally invasive treatments. In the first case, a 24-years-old patient, female, complained of unsatisfactory anterior maxillary size and incisal wear. After the functional and esthetic planning, nanoparticle composite resin by free hand technique was indicated to rehabilitation. In the second case, a 24-years-old patient, male, reported dissatisfied with his anterior central incisive shape. On clinical examination, maxillary anterior conoid teeth were verified. Based on this evaluation, a conservative treatment using minimally invasive ceramic veneers in maxillary central and lateral incisor and ceramic fragments on canine was planed to the smile rehabilitation. It can be concluded that conservative treatment using direct composite resin restorations and minimum thickness ceramic veneers laminate, even with their specific limitations and advantages, provide satisfactory esthetic and functional treatment results, preserving the dental structure.

Dentes com formato anatômico insatisfatório podem causar desarmonia na estética do sorriso. Os tratamentos para restabelecer a estética do sorriso vêm evoluindo concomitantemente com o desenvolvimento dos materiais dentários. A odontologia estética permite um preparo minimamente invasivo através de resinas compostas e laminados cerâmicos. Estes dois métodos de tratamento apresentam algumas vantagens e desvantagens. O objetivo deste artigo é descrever dois relatos de casos clínicos e comparar alternativas para a reabilitação da estética do sorriso pelos tratamentos minimamente invasivos diretos e indiretos. No primeiro caso, paciente de 24 anos do gênero feminino, estava descontente com o tamanho e com o desgaste incisal dos dentes maxilares anteriores. Após o planejamento funcional e estético foi indicado restauração direta com uma resina nanopartículada pela técnica da mão livre. No segundo caso, paciente de 24 anos do gênero masculino relatou insatisfação com a forma dos incisivos centrais superiores. No exame clínico foi observado incisivos conoídes. Baseado no exame clínico foi planejado um tratamento conservador com laminados cerâmicos nos incisivos centrais e laterais, e fragmentos cerâmicos nos caninos. Pode-se concluir que os tratamentos conservadores utilizando resina composta e laminados cerâmicos, mesmo com suas limitações, promove uma estética satisfatória e resultados funcionais preservando a estrutura dental.

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OBJECTIVE: To evaluate the fracture resistance of different intra-radicular post systems in flared root canals. METHODS: Sixty human canines were used. The coronal portion was removed and the root length was standardized at 17 mm. Canals were prepared and filled with gutta-percha/AH Plus sealer. Roots were embedded in self-polymerising acrylic resin blocks. According to the material used, the teeth were randomly divided into three groups (n=20): glass fibre post (GFP): GFP and Z350 resin composite core; pre-fabricated metal post (PMP): PMP and Z350 resin composite core; and cast metal core (CMC): CMC with silver-tin alloy. Coronal reconstruction involved fabrication of metal copings. Samples were submitted to mechanical compression testing at 45º in a universal test machine. Fracture pattern was evaluated under a stereoscope. The fracture strength values were submitted to one-way analysis of variance (ANOVA) and Tukey tests (α=0.05). RESULTS: There was no statistically significant difference between the resistance values among groups (P=0.193). With regard to fracture pattern, GFP showed 55% and PMP 45% of Type I fractures, which considered repairable or favourable, whereas MCC presented 50% of Type V, which was considered irreparable or unfavourable. CONCLUSION: Glass fibre and pre-fabricated metal posts have good fracture resistance to compression and may be used for restoring flared root canals, since they presented fractures mainly involving the filling core, thus facilitating later repair.