The effects of TiO2 nanotubes on bond strength and radiopacity of a self-adhesive resin cement in self-curing mode / Os efeitos de nanotubos de TiO2 na resistência de união e radiopacidade de um cimento resinoso auto-adesivo no modo auto-polimerizável

Objective: The aim of this in vitro study w as t o analyze the influence of the titanium dioxide nanotubes i n a self-cure mode polymerization of a dual resin luting agent through push out bond strength and radiopacity tests. Material and Methods: After mixed with a commercial du al self-adhesive resin cement, three concentrations o f tit anium dioxide nanotubes (0.3, 0.6, and 0.9% by weight) we re analyzed in self-curing mode. T he bond strength to bovine root dentin and fi berglass posts was assessed with the push out bond str ength t est and was evaluated in three thirds (cervical, middle and apical) (n=10), followed by failure mode analysis (SEM), and the ISO standard 9917-2 was followed for radiopacity test (n=10). Data were statistically analyzed by one-way ANOVA test, followed by Tukey's test (α=0.05). Results: Reinforced self-adhesive resin cement with 0.6% titanium dioxide nanotubes showed significant difference compared to the control gr oup for push out test (p=0.00158). The modified groups did not s how significant difference among thirds (p=0.782). Radiopacity sh owed higher value for group w ith 0.9% titanium dioxide nanotubes in comparison w ith control group (p<0.001). Conclusion: The addition of titanium dioxide nanotubes to a self-adhesive resin cement increased the bond strength to dentin and radiopacity values in the self-cure polymerization mode (AU)

Objetivo: O objetivo deste estudo in vitro foi analisar a influência de nanotubos de dióxido de titânio na polimerização química de um agente cimentante resinoso dual através de testes de resistência à união e radiopacidade. Material e Métodos: Após misturado com um cimento resinoso auto-adesivo comercial, três concentrações de nanotubos de dióxido de titânio (0,3, 0,6 e 0,9% em peso) foram analisadas. A resistência da união para a dentina da raiz bovina e os pinos de fibra de vidro foi avaliada pelo teste de push-out e avaliada em três terços (cervical, médio e apical) (n = 10), seguido pelo análise de modo de falha (MEV) e a norma ISO 9917-2 foi seguido para teste de radiopacidade (n = 10). Os dados foram analisados estatisticamente pelo teste ANOVA um fator seguido do teste de Tukey (α = 0,05). Resultados: O cimento resinoso auto-adesivo reforçado com nanotubos de dióxido de titânio a 0,6% mostrou diferença significativa em comparação com o grupo controle para teste de push-out (p=0,00158). Os grupos modificados não mostraram diferença significativa entre os terços (p=0,782). A radiopacidade mostrou maior valor para o grupo com nanotubos de dióxido de titânio 0,9% em comparação com o grupo controle (p<0,001). Conclusão: A adição de nanotubos de dióxido de titânio a um cimento resinoso auto-adesivo aumentou a os valores de resistência de união à dentina e radiopacidade no modo de polimerização química do agente cimentante (AU)

Correlation between mechanical properties and stabilization time of chemical bonds in glass-ionomer cements

Abstract The objective was to evaluate the compressive strength (CS), diametral tensile strength (DTS), flexural strength (FS), and Knoop microhardness (KH) of different conventional restorative glass-ionomer cements (GICs) and to correlate these mechanical properties (MP) with the stabilization time (ST) of their chemical bonds. Eighteen GICs were tested: Bioglass [B], Chemfil Rock [CR], Equia Forte [EF], Gold Label 2 [GL2], Gold Label 9 [GL9], Glass Ionomer Cement II [GI], Ionglass [IG], Ion Z[ IZ], Ionomaster [IM], Ionofil Plus [IP], Ionostar Plus [IS], Ketac Molar Easymix [KM], Magic Glass [MG], Maxxion R [Ma], Riva Self Cure [R], Vidrion R [V], Vitro Fil [VF] and Vitro Molar [VM]. The mechanical strength tests were performed in a universal testing machine. KH readings were done with a diamond indenter. STs were examined by Fourier Transform Infrared spectroscopy (FTIR). Data were analyzed with ANOVA and Tukey test (p<0.05). The Spearman rank test was used to evaluate the dependence between the MPs and ST results. The highest MP values were EF, GL2, GL9, GI and KM and the lowest for MG, MA, B, VF and IM. The longest ST was for GL2 and the shortest was for B. ST correlated positively with MP. GICs with longer chemical bonds ST are generally stronger and the ST value obtained from FTIR was useful in predicting the strength of GICs tested.

Multidisciplinary approach for anatomical correction and diastema closure with laminates veneers: a clinical report / Abordagem multidisciplinar para correção anatômica e fechamento de diastemas com facetas laminadas: relato de caso clínico

Objective: multidisciplinary treatment has become increasingly common in dental offices and this treatment strategy is based on the achievement of a healthy, harmonious, and pleasant smile. In addition, the development of new ceramic systems and the possibility of making indirect restorations with a low thickness, such as laminates veneers, allowed combining highly satisfactory aesthetic properties, preserving the dental structure through minimally Invasive technique. Case report: this paper describes a multidisciplinary approach involving periodontics and restorative dentistry for the successful, functional, and aesthetic treatment in an adult patient. The digital smile design was performed as a guide to plan the clinical case considering factors such as tooth inclination and position, golden proportion, tooth size and shape. Discussion: based on these concepts, the present work reports, through a clinical case, the restoration of aesthetics and function with ceramic laminates veneers in lithium disilicate, in the case of anatomical correction and diastema closure. Conclusion: overall, the multidisciplinary treatment plan demonstrated to have greater advantages both for the aesthetics and function of the patient, as well as for the work team. During the 24-month follow-up, this case presented great functional and aesthetics results. (AU)

Introdução: o tratamento multidisciplinar tornou-se cada vez mais comum nos consultórios odontológicos, sendo uma estratégia baseada no tratamento da obtenção de um sorriso saudável, harmonioso e agradável. Além disso, o desenvolvimento de novos sistemas cerâmicos e a possibilidade de fazer restaurações indiretas com baixa espessura, como facetas laminadas, permitiram combinar propriedades estéticas altamente satisfatórias, preservando a estrutura dentária com o mínimo desgaste. Caso clínico: este artigo descreve uma abordagem multidisciplinar envolvendo Periodontia e Odontologia restauradora para um tratamento funcional e estético em um paciente adulto. O desenho digital do sorriso foi realizado como um guia para planejar o caso clínico, considerando fatores como inclinação e posição do dente, proporção áurea, tamanho e formato do dente. Discussão: com base nesses conceitos, o presente trabalho relata, através de um caso clínico, a restauração estética e funcional com laminados cerâmicos em dissilicato de lítio para correção anatômica e fechamento de diastemas. Conclusão: em geral, o plano de tratamento multidisciplinar demonstrou ter maiores vantagens tanto para a estética e função do paciente, quanto para a equipe de trabalho. Durante os 24 meses de acompanhamento, esse caso apresentou ótimos resultados funcionais e estéticos. (AU)

Fatigue survival and damage modes of lithium disilicate and resin nanoceramic crowns

Abstract Polymer-based composite materials have been proposed as an alternative for single unit restorations, due to their resilient and shock absorbing behavior, in contrast to the brittleness of ceramic materials that could result in failure by fracture. Objective: To evaluate the fatigue strength and damage modes of monolithic posterior resin nanoceramic and lithium disilicate glass ceramic crowns. Methodology: Twenty-six resin nanoceramic (RNC) and lithium disilicate glass ceramic (LD) 2 mm monolithic crowns (n=13) were cemented on composite resin replicas of a prepared tooth and subjected to cyclic load with lithium disilicate indenters for 2 million cycles. Specimens and indenters were inspected every 500,000 cycles and suspended when presenting fractures or debonding. Surviving specimens were embedded in epoxy resin, polished and subsurface damage was analyzed. Specimens presenting fractures or severe subsurface damage were considered as failures. Survival data was subjected to Fisher's exact test; damage modes were subjected to Mann-Whitney test (p<0.05). Results: There were no debonding, cohesive or catastrophic failures. Considering subsurface damage, 53.8% of RNC and 46.2% of LD crowns survived the fatigue test, presenting no statistical difference. Chief damage modes were radial cracks for RNC and inner cone cracks for LD, presenting no statistical difference. Conclusions: The results suggest that if debonding issues can be resolved, resin nanoceramic figures can be an alternative to posterior crowns. Although distinct, damage modes revealed potential to cause bulk fracture in both glass ceramic and resin nanoceramic crowns.

A new approach for Y-TZP surface treatment: evaluations of roughness and bond strength to resin cemen

Abstract Objective This study aims to evaluate the effect of sonochemical treatment on the surface of yttria-stabilized tetragonal zirconia (Y-TZP) before and after the final sintering. Material and Methods Twenty-eight Y-TZP discs were divided into four groups (n=7), according to surface treatment: PRE: pre-sintering sonication with 30% nominal power for 15 min; POS: post-sintering sonication with 30% nominal power for 15 min; JAT: air abrasion with 50-μm alumina particles; and CON: control group with no treatment. The POS and JAT groups were sintered before sonication and the PRE group after sonication. Surface roughness was analyzed using confocal microscopy, after which resin cement cylinders were placed on the surface of the Y-TZP discs and subjected to mechanical microshear bond strength test until fracture. Surface roughness and microshear bond strength values underwent ANOVA and the Tukey tests. Results The surface roughness values for the PRE group (299.91 nm) and the POS group (291.23 nm) were not significantly different (p≥0.05), statistically, and the surface roughness value of the JAT group (925.21 nm) was higher than those of PRE and POS (p=0.007) groups. The mechanical microshear bond strength test showed that there was no statistically significant difference between the groups (p=0.08). Conclusions Therefore, the results showed that sonochemical treatment modifies the Y-TZP surface and is similar to the well-established sandblasting surface treatment regarding the strength of the bond with the resin cement.

Mechanical and optical properties of conventional restorative glass-ionomer cements - a systematic review

Abstract Objectives To perform a systematic review of test methodologies on conventional restorative glass-ionomer cement (GIC) materials for mechanical and optical properties to compare the results between different GICs. Material and Methods Screening of titles and abstracts, data extraction, and quality assessments of full-texts were conducted in search for in vitro studies on conventional GICs that follow the relevant specifications of ISO standards regarding the following mechanical and optical properties: compressive strength, flexural strength, color, opacity and radiopacity. Sources The Latin American and Caribbean Health Sciences (LILACS), Brazilian Bibliography of Dentistry (BBO) databases from Latin-American and Caribbean System on Health Sciences Information (BIREME) and PubMed/Medline (US National Library of Medicine - National Institutes of Health) databases were searched regardless of language. Altogether, 1146 in vitro studies were selected. Two reviewers independently selected and assessed the articles according to pre-established inclusion/exclusion criteria. Among all the properties investigated, only one study was classified as being of fair quality that tested compressive strength and was included. It was observed that many authors had not strictly followed ISO recommendations and that, for some properties (diametral tensile strength and microhardness), there are no guidelines provided. Conclusions It was not possible to compare the results for the mechanical and optical properties of conventional restorative GICs due to the lack of standardization of studies.

Pre-sintered Y-TZP sandblasting: effect on surface roughness, phase transformation, and Y-TZP/veneer bond strength

Abstract Sandblasting is a common method to try to improve the Y-TZP/veneer bond strength of dental prostheses, however, it may put stress on zirconia surfaces and could accelerate the t→m phase transformation. Y-TZP sandblasting before sintering could be an alternative to improve surface roughness and bonding strength of veneering ceramic. Objectives. The aim of this study was to analyze the effect of Y-TZP pre-sintering sandblasting on surface roughness, phase transformation, and the Y-TZP/veneer shear bond strength. Material and Methods. The Y-TZP specimen surface underwent sandblasting with aluminum oxide (50 μm) pre-sintering (Z-PRE) and post-sintering (Z-POS). Z-CTR was not subjected to surface treatment. After ceramic veneer application, the specimens were subjected to shear bond testing. Surface roughness was analyzed by confocal microscopy. Y-TZP monoclinic and tetragonal phases were evaluated by micro-Raman spectroscopy. Shear bond strength and surface roughness data were analyzed by One-way ANOVA and Tukey tests (α=0.05). Differences in the wave numbers and the broadening bands of the Raman spectra were compared among groups. Results. Z-POS (9.73±5.36 MPa) and Z-PRE (7.94±2.52 MPa) showed the highest bond strength, significantly higher than that of Z-CTR (5.54±2.14 MPa). The Ra of Z-PRE (1.59±0.23 µm) was much greater and significantly different from that of Z-CTR (0.29±0.05 µm) and Z-POS (0.77±0.13 µm). All groups showed bands typical of the tetragonal (T) and monoclinic (M) phases. Y-TZP sandblasting before sintering resulted in rougher surfaces but did not increase the shear bond strength compared to post-sintering and increased surface defects. Conclusions. Surface treatment with Al3O2, regardless of the moment and application, improves the results of Y-TZP/veneer bonding and is not a specific cause of t→m transformation.

Marginal adaptation in proximal cavities restored with composites and other materials / Adaptação marginal em cavidades proximais com compósitos e outros materiais

Objective: To evaluate the marginal adaptation, in enamel (E) and dentin (D), of composite resin (CR) associated with flowable resin composite (flow), bulk fill flowable base (bulk) and resin modified glass ionomer cement (RMGIC) in slot cavities. Material and Methods: The study was conducted after approval (Protocol No. 21148413.4.0000.5417) from Ethics Committee. Forty extracted human molar teeth were randomly assigned in eight experimental groups: E-CR, E-BULK, E-FLOW, E-RMGIC, D-CR, D-BULK, D-FLOW, D-RMGIC. The occlusal surface was planned, two slot cavities with standard sizes (depth: 2.0 mm, height: 2.5 mm, width: 2.0 mm) were created on a machine for making cavities. The teeth were restored and after 24h subjected to 2000 cyclic loading and sectioned for analysis of marginal adaptation by scanning electron microscopy (SEM). The micrographs were analyzed with the Image J program to measure the size of marginal gaps. The data were transformed into percentages (%GAPS = LG ÷ LM × 100) and analyzed by 2-way ANOVA followed by the post hoc Tukey test (α=0.05). Results: There was a significant difference between different treatments (p0.05). Conclusions: It was concluded that restorations with flowable composite resin and bulk fill liners exhibit the same behavior, but the RMGIC liner increased marginal gap (AU)

Objetivo: Avaliar a adaptação marginal, em esmalte (E) e dentina (D), de restaurações com resina composta (RC) associada a resina composta fluida (flow), resina bulk fill (bulk) e cimento de ionômero modificado por resina (CIVMR) em cavidades tipo slot. Materiais e Métodos: O estudo foi realizado após aprovação no Comitê de Ética e Pesquisa (Protocolo no. 21148413.4.0000.5417). Quarenta molares humanos foram aleatoriamente distribuídos em oito grupos experimentais: E-RC, E-BULK, E-FLOW, E-CIVMR, D-RC, D-BULK, D-FLOW, D-CIVMR. A superfície oclusal foi planificada e duas cavidades tipo slot com tamanhos padronizados (profundidade: 2,0 mm, altura: 2,5 mm, largura: 2,0 mm) foram realizadas em uma máquina para confecção de cavidades. Os dentes foram restaurados e, após 24h, submetidos a 2000 ciclos mecânicos e foram seccionados para análise da adaptação marginal em microscopia eletrônica de varredura (MEV). As micrografias foram analisadas através do programa Image J para medir as fendas marginais. Os dados foram transformados em porcentagens (%fendas = largura da fenda / largura da margem x 100) e analisados através do teste ANOVA-2 critérios seguido do teste de Tukey (α=0,05). Resultados: Houve diferença significante entre os diferentes tratamentos (p0,05). Conclusões: Concluiu-se que as restaurações com base de resina flow e bulk fill exibiram o mesmo comportamento, mas a base de CIVMR aumentou a fenda marginal. (AU)

Material Selection for Constructing an Intraoral Stent Used in Radiotherapy: Analysis of Density and Structure.

Neck and head cancer is a very common disease. Radiotherapy is one of the treatments, and its side effects affect the patient’s quality of life because the radiation targets both neoplastic and healthy tissues. This study aimed to select material that exhibited the greatest number of characteristics that are biocompatible with human tissue and that are strong enough to construct an intraoral stent. The stent would be used to mechanically isolate the palate, tongue, and mouth floor to prevent radiation in head and neck cancer cases requiring radiotherapy, thereby aiming to decrease the treatment’s side effects. The following materials were selected to be submitted to a first analysis by computed tomography: polyacetal (white and black), polymethylmethacrylate (PMMA), polyurethane, and polyvinyl chloride. By observing the density through Hounsfield unit (HU) analysis, the materials with HU values closest to that of water (HU = 0) were selected for the structural analysis after the radiotherapeutic protocol through micro Raman spectroscopy. After undergoing radiation, PMMA with HUs of 177 and 179 without structural modification had the best density results; this was verified by micro Raman spectroscopy. PMMA seems to be a promising material due to its density and structural integrity after the radiotherapeutic protocol. Clinical Significance: The material with the HU value that is most compatible with the oral tissues does not interfere with the action of x-ray beams or with the main function of mechanically isolating the oral tissues, thus reducing the side effects from radiotherapy, improving the patient’s quality of life after the treatment.

An Indirect Method to Measure Abutment Screw Preload: A Pilot Study Based on Micro-CT Scanning

This study aimed to measure the preload in different implant platform geometries based on micro-CT images. External hexagon (EH) implants and Morse Tapered (MT) implants (n=5) were used for the preload measurement. The abutment screws were scanned in micro-CT to obtain their virtual models, which were used to record their initial length. The abutments were screwed on the implant with a 20 Ncm torque and the set composed by implant, abutment screw and abutment were taken to the micro-CT scanner to obtain virtual slices of the specimens. These slices allowed the measurement of screw lengths after torque application and based on the screw elongation. Preload values were calculated using the Hooke's Law. The preloads of both groups were compared by independent t-test. Removal torque of each specimen was recorded. To evaluate the accuracy of the micro-CT technique, three rods with known lengths were scanned and the length of their virtual model was measured and compared with the original length. One rod was scanned four times to evaluate the measuring method variation. There was no difference between groups for preload (EH = 461.6 N and MT = 477.4 N), but the EH group showed higher removal torque values (13.8±4.7 against 8.2±3.6 Ncm for MT group). The micro-CT technique showed a variability of 0.053% and repeatability showed an error of 0.23 to 0.28%. Within the limitations of this study, there was no difference between external hexagon and Morse taper for preload. The method using micro-CT may be considered for preload calculation.

Resumo Este estudo teve como objetivo medir a pré-carga em diferentes conexões implante/pilar baseado em imagens de micro-CT. Implantes de hexágono externo (EH) e Cone Morse (MT) (n = 5) foram utilizados para a medição de pré-carga. Os parafusos de pilares foram digitalizados em um micro-CT de alta resolução para obter seus modelos virtuais, que foram utilizados para registrar o comprimento inicial. Os pilares foram parafusados sobre o implante com um torque de 20 Ncm e, o conjunto composto por implante, parafuso do pilar e pilar foi levado para o micro-CT para obter cortes virtuais dos espécimes. Esses cortes permitiram a medida do comprimento dos parafusos após a aplicação do torque. Assim, com base no alongamento dos parafusos, os valores de pré-carga foram calculados usando a Lei de Hooke. A pré-carga de ambos os grupos foram comparados pelo Test-t independente. O torque de remoção de cada espécime foi registrado. Para avaliar a precisão da técnica de micro-CT, três bastões foram escaneados em micro-CT e o comprimento do seu modelo virtual foi comparado com o comprimento original dos bastões. Um bastão foi digitalizado e mensurado quatro vezes para avaliar a variação do método de medição e a sua repetitividade. Não houve diferença entre os grupos para a pré-carga (EH = 461,6 N e MT = 477,4 N), no entanto o grupo EH apresentou maiores valores de torque de afrouxamento do parafuso (13,8 ± 4,7 contra 8,2 ± 3,6 Ncm para o grupo MT). A técnica de micro-CT mostrou uma variabilidade de 0,053% e a repetitividade apresentou um erro de 0,23 a 0,28%. Dentro das limitações deste estudo, não houve diferença entre Hexágono Externo e Cone Morse para pré-carga. O método baseado em imagens de micro-CT pode ser considerado para mensuração da pré-carga.

Diagnóstico e conduta clínica perante dentes supranumerários localizados em pré-maxila: relato de um caso / Diagnosis and clinical approach of supernumerary teeth in anterior maxila: a case report

Dentre os defeitos do desenvolvimento craniofacial, a Hiperdontia representa uma alteração de número do desenvolvimento dentário relevante, devido a sua alta prevalência e ao seu potencial para comprometer funcional e esteticamente os pacientes acometidos. O presente trabalho descreve o caso de um paciente de 5 anos de idade, acometido pelo desenvolvimento de dois elementos dentários supranumerários em região anterior de maxila. O caso foi diagnosticado a partir de avaliação radiográfica associada à erupção ectópica de um dos elementos supranumerários por face palatina dos incisivos superiores decíduos, os quais se apresentavam com mobilidade fisiológica devido ao desenvolvimento de seus sucessores. O tratamento eleito para o caso foi a extração dos elementos decíduos com mobilidade e do elemento supranumerário erupcionado, optando-se pela remoção do elemento supranumerário incluso em momento posterior, uma vez que este não se encontrava associado a nenhum comprometimento funcional ou estético e também pelo fato de que a remoção do mesmo geraria alta morbidade ao paciente pediátrico. O caso descrito salienta a importância do cirurgião no acompanhamento do desenvolvimento craniofacial humano, uma vez que este pode ser acompanhado de distúrbios significativos. Além disso, o presente caso alerta a comunidade odontológica para a importância do bom planejamento e conduta terapêutica adequados para cada caso

Among the defects of craniofacial development, Hyperdontia represents a relevant number of changes of the tooth development, due to its high prevalence and its potential for functional and aesthetically compromising the affected patients. This paper describes the case of a 5 years-old patient, affected by the development of two dental elements supernumerary in the anterior maxilla. The case was diagnosed from radiographic evaluation associated with clinical aspect of ectopic eruption of the supernumerary elements by palatal face of the upper deciduous incisors, which presented with physiological mobility due to the development of their successors. The treatment chosen for the case was the extraction of the deciduous elements mobility and supernumerary element erupted opting up by removal of the supernumerary element included at a later stage, since this was not associate with any functional or esthetic damage, and also by the fact that the removal of that would generate high morbidity to pediatric patient. This case emphasizes the importance of dental surgeon in monitoring of human craniofacial development, since this may be accompanied by significant disorders. Moreover, this case alerts the dental community to the importance of good planning and adequate therapeutic approach for each case

Degree of conversion of a flowable composite light-activated through ceramics of different shades and thicknesses

Abstract The cementation of thin ceramic veneers employing fluid light-activated resin-based materials is a common procedure in the dental practice. Aim: To evaluate the influence of ceramic thickness and shade on the degree of conversion (DC) of a flowable light-activated material. Methods: flowable resin composite (Tetric N-Flow - shade A1) was light-activated through ceramic discs of two shades (IPS Classic - A1 and A3) in three thicknesses (0.5, 0.7 and 1.0 mm). For control, the resin composite was light-activated without ceramic interposition. DC was evaluated by FTIR (n=5). Data were analyzed by one-way ANOVA and Dunnett's T3 test (α=0.05). Results: Statistically significant differences between groups were observed (p<0.001). Control group (without the interposition of ceramic) showed the highest mean for DC (71.9± 1.7). Considering the interposed ceramic disc groups, the highest DC values were obtained when 0.5 and 0.7 mm A1 ceramics were used (64.6±1.2 and 64.4 5.0, respectively) and the lowest DC values were obtained for 0.7 and 1 mm A3 ceramics (61.74±0.9 and 62.0±1.9, respectively). Conclusions: No flowable resin composite group with interposing ceramics reached a DC similar to the control group.

Effectiveness of plant-derived proanthocyanidins on demineralization on enamel and dentin under artificial cariogenic challenge

Dental caries is considered a disease of high prevalence and a constant problem in public health. Proanthocyanidins (PAs) are substances that have been the target of recent studies aiming to control or treat caries. Objective The aim of this in vitro study was to evaluate the efficacy of a treatment with grape seed extract, under cariogenic challenge, to minimize or even prevent the onset of caries in the enamel and dentin. Material and Methods Blocks of enamel and dentin (6.0x6.0 mm) were obtained from bovine central incisors, polished, and selected by analysis of surface microhardness (SH). The blocks were randomly divided into 3 groups (n=15), according to the following treatments: GC (control), GSE (grape seed extract), GF (fluoride – 1,000 ppm). The blocks were subjected to 6 daily pH cycles for 8 days. Within the daily cycling, the specimens were stored in buffered solution. The blocks were then analyzed for perpendicular and surface hardness and polarized light microscopy. Results The means were subjected to statistical analysis using the ANOVA and Fisher's PLSD tests (p<0.05). For enamel SH, GF showed the highest hardness values. In the dentin, GF was also the one that showed higher hardness values, followed by GSE. Regarding the cross-sectional hardness values, all groups behaved similarly in both the enamel and dentin. The samples that were treated with GSE and fluoride (GF) showed statistically higher values than the control. Conclusion Based on the data obtained in this in vitro study, it is suggested that grape seed extract inhibits demineralization of artificial carious lesions in both the enamel and dentin, but in a different scale in each structure and in a smaller scale when compared to fluoride. .

Curing depth of a silorane-based resin composite

Introduction: The silorane-based resin appears aiming to minimize the effects of polymerization shrinkage, but other properties must be studied. Objective: To evaluate the polymerization depth of two composites with different organic matrix. Material and methods: 80 cylindrical specimens were prepared using a metallic matrix, with three layers (top, middle and bottom), 1 mm high and 5 mm in diameter. The specimens were divided into eight groups (n = 10) according to the composite resins: Filtek P90 (3M/ESPE); Filtek Z250 (3M/ESPE), light-cured with a LED device with different irradiance and times (600mW/cm2 x 40s, 1000mW/cm2 x 40s, 1000mW/cm2 x 20s; 1400mW/cm2 x 20s). The irradiance was controlled by placing plastic rings coupled to the device's tip. Immediately after polymerization, the specimens' layers were separated and five Knoop microhardness readings (initial hardness) were performed on each one of the four layers (0, 1, 2, and 3 mm). After 7 day storage in water at 37ºC, new readings were performed (final microhardness). The data were analyzed by four-way ANOVA (resin, energy density, depth and time) and Tukey test (α = 0.05). Results: The microhardness decreased with the depth increasing both in the initial and 7 day readings. The hardness increased with the highest power densities. The resin P90 had lower hardness values. Conclusion: The silorane-based resin showed Knoop microhardness values significant smaller than those of methacrylate-based resin in almost all evaluated parameters. However, both presented similar behaviors in relation to the curing depth.

Bonding to bleached enamel treated with 10% sodium bicarbonate: a one-year follow-up / Restaurações adesivas em esmalte clareado tratado com solução de bicarbonato de sódio a 10% - 1 ano de avaliação clínica

Objective: The aim of this case report is to present the 1-year follow-up of composite resin restorations performed on imediate bleached enamel. Clinical considerations: The presence of residual oxygen after bleaching may be responsible for inhibiting the polymerization of the monomers present in the adhesive systems, leading to the failure of the restorative procedure. The use of antioxidants, especially the 10% sodium bicarbonate solution (SB), could be a fast and practical alternative to improve the bond strength of these restorations. Patient with high aesthetic demands submitted to the office bleaching with hydrogen peroxide 35% received restorative procedure performed immediately after bleaching. After unsatisfactory resin composite restorations removal, the antioxidant SB was applied and the restorative procedure performed.After one year, the clinical performance of the restorations were successful, showing no signs of failure nor infiltration. Conclusions: The use of the 10% sodium bicarbonate in bleached enamel seems to be a viable alternative for clinical practice, however a large number of restorations of longitudinal researches will be need for corroborate this technique...

Objetivo: O objetivo desse relato de caso clínico é apresentar o acompanhamento de 1 ano de restaurações de resina composta realizadas em esmalte dentário recém-clareado. Considerações clínicas: A presença de oxigénio residual após o clareamento dentário pode ser responsável pela inibição da polimerização dos monômeros presentes nos sistemas adesivos, que pode acarretar em falha do processo restaurador. A utilização de antioxidantes, especialmente a solução de bicarbonato de sódio a 10% (SB), pode ser uma alternativa rápida e prática para melhorar a resistência de união destas restaurações. Em um paciente com alta exigência estética submetido ao clareamento de consultório com peróxido de hidrogénio a 35% foi realizado o procedimento restaurador imediatamente após o clareamento dentário. Após a remoção das restaurações insatisfatórias de resina composta, o antioxidante SB foi aplicado e o procedimento restaurador realizado imediatamente. Após um ano, o desempenho clínico das restaurações de resina composta foram adequadas, não mostrando sinais de falhas nem de infiltração marginal. Conclusões: O uso da solução de bicarbonato de sódio a 10% no esmalte clareado se mostrou uma alternativa viável e prática, contudo um maior número de estudos longitudinais é necessário afim de corroborar com a técnica utilizada neste caso clínico...

Atraumatic restorative treatment in Brazilian schoolchildren: 12 months preliminary clinical results / Tratamento restaurador atraumático em escolares brasileiros: 12 meses de resultados clínicos preliminares

Objective: To evaluate the clinical efficacy between two GICs, Fuji IX (GC Int. Corp.) and Ketac Molar (3M ESPE), used in Atraumatic Restorative Treatments (ART). Materials & Methods: A total of 82 children aged among 6-9 years old were included in this study. The materials employment criteria application followed the “split mouth” design, 71 restorations and 98 sealants were carried out with the Fuji IX in the left hemi arches and 70 restorations and 99 sealants were carried out with the Ketac Molar in theright hemi arches. The procedures were conducted in a school that did not have dental equipment. Previously to the restorative procedure, the children were supervised during tooth brushing. A trained dentist carried out all the restorations and sealants at the school playground with natural light and the teeth were isolated with cotton rolls. The performance of the restorations and sealants was evaluated by visual inspection in a 12 months preliminary follow up by one blinded trained examiner. Results: No significant difference was shown between the success rate of the GICs Fuji IX and Ketac Molar for the restorations (p > 0.05) and sealants (p > 0.05). Regardless of the material, the success rates were 82% for the sealants, 76% for the class I and 73% for the class II restorations. Conclusion: The GICs had a good performance and ART preliminary results provided curative and preventive treatments for patients who do not have access to conventional treatment.

Objetivo: Avaliar a eficácia clínica entre dois CIVs, Fuji IX (GC Int. Corp.) e Ketac Molar (3M ESPE), utilizados no Tratamento RestauradorAtraumático (TRA). Material e Métodos: 82 crianças com idade entre 6-9 anos foram incluídas no estudo. A utilização dos materiais seguiu o desenho de boca dividida, 71 restaurações e 98 selantes foram realizados com Fuji IX nas hemi arcadas esquerdas e 70 restaurações e 99 selantes foram realizados com Ketac Molar nas hemi arcadas direitas. Os procedimentos foram realizados em uma escola sem consultório odontológico. Previamente aos procedimentos, as crianças escovaram os dentes sob supervisão. Um dentista treinado realizou todas as restaurações e selantes no pátio da escola com luz natural e os dentes foram isolados com rolos de algodão. A performance das restaurações e selantes foram avaliadas por inspeção visual em 12 meses de acompanhamento por um examinador treinado e cego. Resultados: Não se observou diferença significante entre as taxas de sucesso do CIVs Fuji IX e Ketac Molar para restaurações (p > 0,05) e selantes (p > 0,05). Independente do material, a taxa de sucesso foi 82% para selantes, 76% para restaurações classe I e 73% para classe II. Conclusão: Os CIVs tiveram uma boa performance e os resultados preliminares do TRA promoveram tratamentos curativos e preventivos para pacientes que não tem acesso ao tratamento convencional.

Avaliação da eficácia do clareamento externo com peróxido de hidrogênio a 6% e 7.5% / Evaluation of the effectiveness of external bleaching using 6% and 7.5% hydrogen peroxide

O presente estudo avalia in vivo a eficácia do tratamento clareador caseiro e a presença ou não de sensibilidade (SE), comparando dois agentes de uso diurno: (1) peróxido de hidrogênio (PH) 6% e (2) PH 7,5% com o peróxido de carbamida (PC) a 10% de uso noturno, como controle. Para tal, 35 pacientes foram selecionados e, em cada indivíduo, a arcada superior ou inferior foi aleatoriamente designada para uso de um dos agentes clareadores, dando início ao tratamento de quatro semanas pela arcada superior. Elaboraram-se escores para comparar as colorações inicial e final, por meio de fotografias e escala Vita. Como resultado, não houve diferença estatisticamente significante do tratamento clareador e da percentagem da SE entre o PC10%, PH6% e 7,5%. Conclui-se que o uso do PH6% ou PH7,5% por menos tempo e durante o dia possibilita ao tratamento clareador ser tão eficaz quanto o PC10% da técnica noturna.

This in vivo study evaluated the effectiveness and sensitivity rates (SE) of home-made bleaching treatment comparing two agents for daytime use: (1) 6% hydrogen peroxide (HP) and (2) 7.5% HP, and 10% carbamide peroxide (CP) for overnight use as a control. For this purpose, 35 individuals were selected and each was randomly assigned the maxillary or mandibular arch for using one of the bleaching agentes. The treatment was made initially in the maxillary arch for 4 weeks. Scores were recorded to compare the initial and final shades by photographs using a shade guide (Vita Classical). The results showed no significant difference for bleaching treatment and percentage of SE between 10% CP, 6% HP, and 7.5% HP. It was concluded that using 6%HP or 7.5%HP for shorter periods of time during the day was as effective as 10% CP overnight bleaching technique using mouthguards.

A critical review on the conversion degree of resin monomersby direct analyses / Revisão crítica sobre o grau de conversão de monômeros resinosos detectados por métodos de análise direta

Objectives: The aim of this study was to carry out a review on the methods of direct detection of theconversion degree of composite resins. Materials & methods: The authors searched the Cochrane Library,Embase, PubMed, and the Web of Science (ISI) for papers dated from January 1991 to November 2011.The search was complemented by manual searches of the reference lists from each identified relevant paper.The main search terms were: “degree of conversion”, “monomers”, "polymers”, “composite”, “pre-gel”,“post-gel”, “residual monomers” and “double bond”. The inclusion criteria were studies that evaluatedconsolidated methods in the literature to directly evaluate the degree of conversion. Excluded studieswere those considered to be unrelated to the question addressed, such as mechanical and physicalproperties and also monomers from adhesive systems and compomers. The selected papers were assignedto a score (A, B or C), according to the predetermined criteria. Results: A total of 45 papers were selectedand 15 papers were included in the critical appraisal. Two articles were labeled as grade A, nine articleswere labeled as grade B, and four articles were labeled as grade C. Conclusions: According to thedefinitions of evidence levels, the current article study showed a strong evidence of review. Clinicalsignificance: The degree of conversion predicts the quality of polymers because the higher degree ofconversion, the higher strength of the resin matrix.

Objetivos: O objetivo deste estudo foi revisar os métodos de detecção direta do grau de conversão de resinas compostas. Material e Métodos: Os autores pesquisaram artigos publicados no período de Janeiro de 1991 a novembro de 2011, nas bases de dados Cochrane Library, Embase, PubMed e Web of Science (ISI). A pesquisa foi complementada por pesquisa manual das listas de referências de cada artigo identificado como relevante sobre o tema. Os principais termos pesquisados foram: “grau de conversão”, “monômeros”, “polímeros”, “compósito”, “pré-gel”, “pós-gel”, “monômeros residuais” e“dupla ligação”. Os critérios de inclusão foram estudos que avaliaram diretamente o grau de conversão utilizando métodos consolidados na literatura. Os estudos excluídos foram aqueles considerados não relacionados à questão abordada, como estudos sobre propriedades físicas e mecânicas e também sobre monômeros de sistemas de união e compômeros. Os artigos selecionados foram divididos na classificação A, B ou C, de acordo com critérios pré-determinados. Resultados: Quarenta e cinco artigos foram selecionados e quinze artigos foram incluídos na avaliação. Dois artigos foram classificados como grade A, nove artigos como grade B e quatro artigos como grade C. Conclusões: De acordo com as definições dos níveis de evidência, o presente estudo apresentou forte evidência de revisão. Significância Clínica: O grau de conversão prediz a qualidade dos polímeros formados, uma vez que quanto maior o grau de conversão, mais resistente é a matriz resinosa.