Avaliação da resistência de união de reparos em resinas compostas convencionais e bulkfill

Técnicas de reparos de restaurações vêm sendo amplamente utilizadas como um tratamento alternativo e conservador á substituição de restaurações defeituosas. O conhecimento do material a ser reparado e de um protocolo ideal, permitiria uma melhor relação biomecânica entre dente e material restaurador e possibilitaria técnicas eficazes e menos invasivas. O objetivo do presente estudo foi avaliar a resistência de união de reparo de diferentes resinas compostas, sob a influência de tratamentos de superfície, especialmente em relação a uma nova proposta comercial denominada de resinas "bulk fill". Para isso, foram confeccionados corpos de prova com diâmetro de 8mm por 4mm de altura, de diferentes classes de resinas compostas: Z350XT, Z250XT, Grandio, Epricord, Tetric Bulkfill, Xtra Fill e Sonic Fill (n=15). Estes passaram por processo de envelhecimento artificial, realizado por meio de armazenamento em estufa com saliva artificial por 3 meses, sendo realizada a troca da saliva semanalmente, e finalizado com termociclagem 5o e 55ºC por 20 segundos em água para 1000 ciclos. Foram distribuídos aleatoriamente em três subgrupos, de acordo com o tratamento de superfície (n=5): G1- Controle- sem tratamento prévio; G2- Jateamento óxido alumínio; G3- Jateamento óxido de sílica. Após a aplicação dos respectivos tratamentos de superfície, cada espécime foi reparado com resina composta Z100 em incrementos de aproximadamente 2mm e fotopolimerizado em um aparelho de fotopolimerização convencional (Bluephase, Ivoclar Vivadent, Liechtenstein) até obtenção 4 mm de altura. A seguir os espécimes foram submetidos a novo ciclo de envelhecimento artificial por uma semana em estufa com saliva artificial, e termociclagem 5o e 55ºC por 20 segundos em água para 1000 ciclos. As amostras foram seccionadas em seu longo eixo em máquina de corte (Isomet 1000, Buehler Ltd, Lake Bluff, IL, EUA), a fim de se obter espécimes no formato de paralelepípedo, com a linha de união localizada centralmente. Cada espécime foi individualmente fixado em máquina de microtração Micro Tensile Tester- MTT (BISCO, Inc. 1100 W. Irving Park Rd. Schaumburg, IL 60193 USA 1- 800-247-3368), e submetido a teste de microtração com velocidade de 0,5 mm/min e célula de carga de 500N. Realizou-se análise de variância para avaliar a influência dos diferentes materiais e tratamentos de superfície na resistência de união de reparos. O padrão de fratura observado nos reparos foi analisado por meio do teste de qui-quadrado( 2 ), para uma com significância estatística de 5%. A análise de variância mostrou que existe diferença estatisticamente significativa (p=0,001) entre a resistência coesiva dos materiais, e para interação material e tratamento de superfície sobre a resistência de união dos reparos (p=0,001). O teste de quiquadrado( 2 ) também mostrou que existe associação entre o tipo de fratura e as variáveis materiais e tratamentos de superfície (p=0.001). Concluindo que, as diferentes classes de resinas compostas testadas respondem de maneira diferente frente aos tratamentos de superfície aplicados, não sendo possível estabelecer um protocolo clínico ideal para procedimentos de reparo. Além disso, as resinas bulkfill testadas possuem resistência de união aceitável, semelhante às demais classes de resinas compostas, demonstrando que procedimentos de reparo são indicados para esses materiais.Restoration repair techniques have been widely used as an alternative and conservative treatment for replacement of defective restorations. The knowledge of the material to be repaired and an ideal protocol would allow a better biomechanical relationship between tooth and restorative material and would allow techniques effective and less invasive. The aim of this study was to evaluate the repair's bond strength of different composite resins under the influence of surface treatments, especially in relation to a new commercial proposal called Bulk-fill Resin-based Composites. For this, specimens were prepared with 8 mm diameter by 4 mm in height, of different classes of composite resins: Z350XT, Z250XT, Grandio, Epricord, Tetric Bulkfill, Xtra Fill e Sonic Fill (n=15). These were submitted to artificial aging process by storing in an oven with artificial saliva for 3 months, and their exchange performed weekly and finished 5 o and 55°C thermocycling for 1000 cycles. They were randomly divided into three subgroups, according to the surface treatment (n=5): Control group- without treatment (G1), Aluminum oxide blasting (G2), Silica oxide blasting (G3). After applying the respective surface treatments, each specimen was repaired with composite resin (Z-100, 3M ESPE) in increments of 2mm, approximately, and light cured in a conventional light-curing unit (Bluephase, Ivoclar Vivadent, Liechtenstein) to obtain 4 mm height. Then specimens were subjected to a new cycle of artificial aging for one week incubated in artificial saliva and thermal cycling 5 and 55°C for 1000 cycles. The samples were sectioned in their long axis in a cutting machine (Isomet 1000, Buehler Ltd, Lake Bluff, IL, USA) in order to obtain the specimens in parallelepiped shape with union line centrally located. Each specimen was individually set at a micro-tensile machine Micro Tensile Tester - MTT (BISCO, Inc. 1100 W. Irving Park Rd. Schaumburg, IL 60193 USA 1-800-247-3368), and submitted to micro-tensile test at 0.5 mm/min speed with a 500 N load cell. It was performed variance analysis for there is influence of different materials and surface treatments on the bond strength of repair. The fracture pattern observed in repairs was analyzed using the chi-square test ( 2 ) with 5% statistical significance level. Analysis of Variance showed that there was a statistically significant difference (p=0.001) between the tensile strength of materials, and for interaction materials and surface treatment on bond strength of repair (p=0.001). There was association between the type of fracture and the variables material and surface treatments (p=0.001). It can be concluded that the different classes of composites tested respond differently compared to the applied surface treatment and it is not possible to establish a clinical protocol for repair procedures. Moreover, the tested bulk fill resins have acceptable bond strength, similar to other classes of composites, demonstrating that these materials are suitable for repair procedures.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Color stability of conventional and bulk fill composite resins

Objective: This study compared the color stability of different dental composite resins after prolonged exposure to a coffee solution. Methods: Sixty-four cylindrical discs (10 mm diameter x 2 mm thickness) were prepared using 8 different dental composite resins (n=8, per group). The specimens were first immersed in artificial saliva for 24 h followed by immersion in a coffee solution for 14 days. The assessment of chromatic variation (ΔE) was performed with the aid of a Vita Easyshade Advanced spectrophotometer (VITA Zahnfabrik, Bad Sackingen, Germany). The color of each specimen was calculated based on the L*, a* and b* coordinates of the CIELab system. Results: Grandio SO had the lowest average chromatic variation (ΔE=7.77) after immersion in coffee solution. Durafill VS, Grandio and Z350 XT (ΔE=8.58; ΔE=9.52; ΔE=10.39, respectively) showed similar chromatic variation, with no statistical difference in relation to Grandio SO. However, the other dental composite resins evaluated showed statistically higher values of ΔE compared to Grandio SO, and Enamel HRi (ΔE=20.56) demonstrated the highest chromatic variation. Conclusion: The Bulk Fill and hybrid composite resins from the same manufacturer (Micerium, Avegno, Italy) showed greater chromatic variation than the other composite resins tested. Grandio SO (Voco, Cuxaven, Germany) had the lowest ΔE variation

New Parameter for In-Office Dental Bleaching

Dental bleaching is considered a conservative and biologically safe treatment for discolored teeth. Despite this, one of the major undesirable effects of bleaching is dentin sensitivity which may occur during and after treatment. To address these sensitivity issues, new dental bleaching preparations with lower concentrations of hydrogen peroxide (H2O2) have recently been introduced to the market. This paper presents a clinical case report of a 20-year-old female patient admitted to the Araraquara Dental School, UNESP, Brazil. The patient underwent dental bleaching using one of the new products with reduced hydrogen peroxide concentration, Lase Peroxide Lite 6%, a 6% H2O2 gel containing titanium oxide nanoparticles doped with nitrogen (6% H2O2/N-doped TiO2)

Hidden caries: a critical review

Hidden caries is a type of lesion visualized in dentin, mainly by means of bitewing radiographs, in which, clinically, the occlusal enamel appears healthy or minimally demineralized and radiographically presents progressive demineralization in dentin, which may progress and compromise the pulp-dentin complex. Although the etiology of hidden caries is unknown, many theories have been studied, including structural and anatomical defects of enamel, their specific microbiota and the use of fluoride, which is most accepted theory. Considering the clinical concern, since these lesions have a silent progression and often are not detected on routine clinical examinations, this study aims to conduct a critical discussion of the etiology, prevalence, diagnostic methods and treatment decision for lesions of hidden caries, alerting professionals about the importance of routine use of bitewing radiographs even in patients considered “cariesfree” or low risk of caries, for more effective diagnosis

Clinical effectiveness of fluorescence, digital images and ICDAS for detecting occlusal caries

Abstract Introduction The detection of small caries lesions is still a challenge for dental professionals who in their clinical practice have a wide variety of methods to detect caries on occlusal surfaces. Objective To clinically assess the effectiveness of the Vista Proof fluorescence camera, the Vista Cam digital intraoral micro camera and the International Caries Detection and Assessment System (ICDAS) visual criterion for detecting caries lesions on occlusal surfaces of permanent teeth. Material and method One hundred and seven posterior teeth from adult patients were examined visually and by means of digital radiographs by an examiner who rated them according to the presence or absence of occlusal caries. The teeth were then assessed by the other examiner using ICDAS, fluorescence and magnified digital images. The effectiveness of the methods was measured based on sensitivity, specificity, positive and negative likelihood ratio. For each method, the Receiver Operating Characteristic (ROC) curve and the Area Under the ROC curve (AUROC) were estimated. Result There was exceptional discrimination capacity for the intraoral images (AUROC=.93) and the ICDAS (AUROC=.91), with no significant statistical difference between them (z=.35, p=.73). The fluorescence exhibited an acceptable discrimination capacity (AUROC=0.78), although it was lower than the others. The positive likelihood ratio for the fluorescence was only 2.32, compared to 20.58 for the intraoral image and 58.11 for the ICDAS. Conclusion Both methods and the ICDAS exhibited an adequate clinical performance, although the ICDAS and intraoral image were more effective than the fluorescence

A novel approach for in-office tooth bleaching with 6 % H2O2/TiO_N and LED/laser system—a controlled, triple-blinded, randomized clinical trial

The purpose of this randomized, parallel, tripleblinded clinical trial was to compare efficacy and tooth sensitivity (TS) after use of an in-office bleaching agent of 6 % hydrogen peroxide containing nanoparticles of nitrogendoped titanium oxide (HP6) vs. 35 % hydrogen peroxide (HP35). Forty-eight volunteers were randomly divided either a HP6 or HP35. Two clinical sessions were performed with an interval of 7 days between them for each group. In each session, two consecutive applications of each bleaching agent were performed and activated by a hybrid LED/laser light. Efficacy was determined by color alteration (ΔE), recorded with reflectance spectroscopy. It was assessed at baseline and after the first and second bleaching session. TS was characterized according to occurrence, intensity, duration, and type. Efficacy was analyzed by repeated measures analysis of variance (ANOVA) and post hoc Bonferroni test, and TS was analyzed by means of chi2 test (α= 0.05). For HP35, highest and significant values of ΔE were found after bleaching when compared to HP6 (p = 0.002). However, HP35 showed a significantly higher occurrence of TS than HP6 (p = 0.008). Also, intensity and duration were higher in HP35. The majority of volunteers classified the type experienced in their sensitivity in the form of a Bshock.^ The use of HP6 despite reducing efficacy when compared to an in-office bleaching in higher concentration (35 %) produced less tooth sensitivity. Clinical relevance: In terms of tooth sensitivity, the use of lower concentrations of in-office bleaching should be the first choice, suggesting greater biocompatibility and safety compared to a conventional HP35

The Influence on Fracture Resistance of Different Composite Resins and Prefabricated Posts to Restore Endodontically Treated Teeth

Recent formulations of resin-based composites have incorporated different combinations of materials. However, the mechanical and bonding behavior of these materials with intraradicular posts are unclear. This study aimed to evaluate the effect of light-cure and dual-cure resin composite posts on the fracture resistance of endodontically-treated teeth. Materials and Methods: Ninety extracted human upper canines were selected and randomly divided into nine groups (n=10): (G1) endodontically treated teeth without endodontic posts; (G2) glass-fiber post cemented with glass-ionomer cement; (G3) endodontic post by dual-cure composite resin (Rebilda DC); (G4) endodontic post by dual-cure composite resin (Cosmecore); (G5) endodontic post by dual-cure composite resin (Bis-Core); (G6) endodontic post by light-cure composite resin; (G7) glass-fiber post customized with flowable composite resin; (G8) glass-fiber post cemented with light-cure composite resin; (G9) glass-fiber post cemented with self-adhesive resin cement. After the post insertion, all specimens were subjected to mechanical (250,000 cycles) and thermocycling (6000 cycles, 5 °C/55 °C) and immediate loading at 45 degrees in a universal testing machine until fracture. The data were analyzed by one-way ANOVA and multiple comparisons using the Fisher LSD Method (p p < 0.001). Conclusions: Within the limitations, the light- and dual-cure post technique did not present lower fracture resistance values as compared to the conventional glass-fiber post

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora