Análise da pigmentação de cerâmicas odontológicas submetidas a diferentes corantes / Analysis of the pigmentation of dentistry ceramics submitted to different dyes

Objetivo: É mérito deste estudo avaliar a pigmentação de cerâmicas odontológicassubmetidas a diferentes tratamentos de superfície e imersasem soluções corantes.Métodos: Foram confeccionadas 60 amostras de cerâmica, divididas em seis grupos. Os grupos G1, G2 e G3 receberam aplicação prévia de glaze, enquanto G4, G5 e G6 foram submetidos a desgastes e polimento. Os grupos foram mantidos em água destilada, açaí e café por um período de 30 dias. Foram realizadas fotografias digitais, seguidas da mensuração de cor da superfície com o programa mColorMeter, com base no sistema CIELab, antes da imersão, após 15 e 30 dias. Para avaliação quantitativa da variação de cor foi utilizada fórmula de ∆E, onde foram obtidos média e desvio padrão de cada grupo. Os dados foram submetidos à análise estatística ANOVA de dois fatores. Resultados: Após a realização da análise estatística, foram estabelecidos as médias e desvios-padrão para variância de cor (∆E) e foi constatado que não houve resultado estatisticamente significativo, em que p ≤ 0,05, para pigmentação em nenhum dos grupos de cerâmicas. Conclusão: Nesse contexto, infere-se que as substâncias café e açaí não promoveram alterações de cor significativas, bem como o glaze e o polimento mostraram-se igualmente eficientes na manutenção da estabilidade de cor das cerâmicas.

Aim: The present study sought to evaluate the pigmentation of dental ceramics submitted to different surface treatments and immersed in staining solutions. Methods: Sixty ceramic samples were manufactured and divided into six groups. Groups G1, G2, and G3 received a prior glaze application, while groups G4, G5, and G6 were submitted to wear and polishing. The groups were maintained in distilled water, açaí, and coffee for a period of 30 days. Digital photographs were taken, followed by color measurement of the surface with the mColorMeter program, based on system CIELab, before immersion, after 15 and 30 days. For quantitative evaluation of color variation, a formula from ∆E was used, where mean and standard deviation of each group were obtained. The data were submitted to ANOVA statistical analysis of two factors. Result: After the statistical analysis, the means and standard deviations for color variance (∆E) were established, and it was found that there were no statistically significant results, with p ≤ 0.05, for pigmentation in any of the groups of ceramics. Conclusion: Therefore, it can be inferred that coffee and açaí substances did not promote significant color changes. Glaze and polishing also proved equally efficient in maintaining the color stability of the ceramics.

Análise quantitativa da rugosidade superficial da cerâmica IPS E. max CAD após acabamento e polimento / Quantitative analysis of surface roughness of IPS E. max CAD ceramics after finishing and polishing

Objetivo: O objetivo deste estudo foi verificar a capacidade do sistema de polimento para reduzir a rugosidade superficial de cerâmicas IPS e.max após acabamento com brocas diamantadas. Métodos: Dez corpos de prova foram confeccionados a partir de blocos de cerâmica de dissilicato de lítio, cristalizados e glazeados (Grupo G1) antes de serem submetidos a leitura com rugosímetro portátil em três pontos diferentes. Foi simulado ajuste oclusal com brocas diamantadas cilíndricas de granulação fina (Grupo G2) e feita uma nova leitura antes de realizar a sequência de polimento com o Kit EVE Diapol H8 (Grupo G3), constituído de três discos de borrachas abrasivas de granulações decrescentes. Após análise da rugosidade superficial do último grupo, as médias das três medições foram submetidas à análise estatística ANOVA e ao teste Tukey com o nível de significância 5%. Resultados:A análise dos dados obtidos revelou diferença estatisticamente significativa entre os três grupos, sendo que no Grupo G2 a rugosidade foi maior que no Grupo G1, que por sua vez foi maior que no Grupo G3. Conclusão: Concluiu-se que o sistema de polimento EVE Diapol H8 reduziu efetivamente a rugosidade superficial após acabamento com brocas diamantadas e proporcionou uma lisura superficial superior àquela dada pelo glaze. (AU)

Aim: This study sought to verify the ability of the polishing system to reduce the surface roughness of IPS E.max ceramics after finishing with diamond drills. Methods:Ten specimens were made from lithium disilicate ceramic blocks, crystallized, and glazed (Group G1) before being subjected to reading with a portable rugosimeter at three different points. Occlusal adjustment was simulated with fine-grained cylindrical diamond burs (Group G2) and re-read before performing the polishing sequence with the EVE Diapol H8 Kit (Group G3), consisting of three rubber diamond discs with decreasing granulations. After analyzing the surface roughness of the last group, the means of the three measurements were submitted to ANOVA statistical analysis and to the Tukey test with a significance level of 5%. Results: The analysis of the data revealed a statistically significant difference between the three groups, with the roughness in the G2 Group being greater than that in the G1 Group, which in turn was greater than that in the G3 Group. Conclusion: It was therefore concluded that the EVE Diapol H8 polishing system effectively reduced surface roughness after finishing with diamond drills and provided a surface smoothness that is superior to that given by the glaze. (AU)

Influence of light source and extended time of curing on microhardness and degree of conversion of different regions of a nanofilled composite resin.

OBJECTIVES: The aim of this study was to evaluate the effects of different light sources and curing time on the degree of conversion and microhardness of two surfaces within a nanofilled composite resin. METHODS: Four experimental groups (n=10) were formed in accordance with the light source (quartz-tungsten halogen (QTH - 600mW/cm(2)), or light-emitting-diode (LED - 800mW/cm(2))) and the time of curing (20 s or 40 s). The specimens were prepared with a circular mould (5 mm ∅ and 2 mm thick), according to the respective protocol, and the Knoop microhardness and degree of conversion was measured at the top and the base of the specimens. The degree of conversion was evaluated by the Fourier transform infrared spectrometer (FTIR). The results were analyzed by ANOVA two-way repeated measures and Tukey's test (α=,05). RESULTS: Both the degree of conversion and microhardness were higher at the top than at the bottom of the specimens. The QTH light source presented better values on the degree of conversion evaluation, but this result was not observed in the microhardness evaluation. Although forty seconds of curing promotes an increased level of microhardness, it did not influence the degree of conversion. CONCLUSION: It could be concluded that increasing the time of curing to 40 s promotes an increase in microhardness, but it does not influence the degree of conversion of a nanofilled composite resin. QTH promote better monomeric conversion; however, the microhardness values are similar to LED curing. For all situations tested, the bottom of the specimens presented lower results than the top.

Dentin bonding on different walls of a class II preparation.

PURPOSE: To evaluate the bond strength on different cavity walls of Class II preparations. Different bonding systems and the effect of thermomechanical cycling were investigated. MATERIALS AND METHODS: Human third molars received MOD preparations with dentin margins. Teeth were randomly assigned to 18 groups (n=5) according to the combination of cavity wall (axial, occlusal, and gingival), bonding system (Single Bond Plus, Clearfil SE Bond, and Adper Prompt) and the occurrence of thermomechanical cycling. Restorations were concluded with Filtek Z250 composite. Specimens were sectioned according to the respective cavity wall (4 slabs/restoration), and the adhesive interface was trimmed to an hourglass shape (1 mm2). Slabs were tested under tension, and failure mode was observed. Bond strength data were analyzed with three-way ANOVA/Tukey's test. RESULTS: Single Bond Plus and Clearfil SE Bond performed similarly under most experimental conditions. Single Bond Plus presented similar bond strength on the three cavity walls, regardless of the aging condition. Clearfil SE Bond exhibited significant differences among cavity walls: the occlusal wall showed higher means in both aging conditions. Non-aged gingival walls and aged axial and gingival walls yielded lower means. Non-aged Adper Prompt produced similar bond strengths on the three cavity walls. After thermomechanical cycling, the gingival wall showed lower means. CONCLUSION: The effect of cavity walls was dependent on the bonding system and thermomechanical cycling. Adper Prompt demonstrated bond strengths lower than Single Bond Plus or Clearfil SE Bond under most experimental conditions.

Effect of cyclic loading on the bond strength of class II restorations with different composite materials.

This study evaluated the effect of cyclic loading on the bond strength of Class II restorations using different composite materials. Class II preparations with gingival margins located in dentin were performed on the mesial surface of 80 bovine incisors. The teeth were randomly allocated to eight groups (n=10) according to resin composite (Filtek Z250, Filtek Supreme, Tetric Ceram HB and Esthet-X) and use of cyclic loading. The restorations were bonded with the Single Bond adhesive system. Simulated aging groups were cyclic loaded for 200,000 cycles with 80N load (2Hz). The specimens were vertically sectioned (two slabs per restoration) and further trimmed into an hour-glass shape at the adhesive interface to obtain a final bonded area 1 mm2. Samples were placed in an apparatus and tested under tension using a universal testing machine. The data were analyzed using two-way ANOVA and Tukey test with a 95% confidence level. Aged groups presented significantly lower means when compared to the groups that were not aged (p=0.03). However, significant differences among composite materials were not observed (p=0.17). Regardless of the restorative composite material used, it could be concluded that the bond strength of Class II restorations at the gingival wall was affected by simulated cyclic loading.

Effect of surface treatments and bonding agents on the bond strength of repaired composites.

STATEMENT OF THE PROBLEM: An adequate repair procedure depends on high bond strength between the existing composite and the new composite. PURPOSE: To evaluate the effect of surface treatments and bonding procedures on the bond strength of repairs performed 24 hours after composite polymerization. MATERIALS AND METHODS: Composite specimens were stored in distilled water at 37 degrees C for 24 hours. Specimens were allocated into 12 groups (N=10) according to the combination of surface treatment (none, air abrasion, diamond bur) and bonding procedure (none, Single Bond after H(3)PO(4) cleansing, Clearfil SE Bond after H(3)PO(4) cleansing, Clearfil SE Bond without H(3)PO(4) cleansing). The ultimate tensile strength (UTS) of the composite was tested in nonrepaired specimens. Twenty-four hours after repair, specimens were sectioned into three slabs and trimmed to an hourglass shape (1 mm(2) area). Slabs were tested under tension and mean bond strengths analyzed with two-way analysis of variance/Tukey and Dunnett tests (alpha=5%). RESULTS: Two groups resulted in repair bond strengths similar to composite UTS: air abrasion combined with Clearfil SE Bond after H(3)PO(4) cleansing, and air abrasion combined with Clearfil SE Bond without H(3)PO(4) cleansing. Combinations of surface treatments and bonding procedures were not statistically different. CONCLUSIONS: When repair procedure was performed 24 hours after composite polymerization, different combinations of surface treatments and bonding procedures affected repair bond strength similarly. There was no statistical difference between the repair bond strength of groups air-abraded and bonded with the self-etching system and composite UTS. CLINICAL SIGNIFICANCE: Only air abrasion associated with a self-etching system provided repair bond strength comparable to composite UTS.

Influence of adhesive systems and flowable composite lining on bond strength of class II restorations submitted to thermal and mechanical stresses.

The purpose of this study was to evaluate the effect of adhesive systems and flowable composite lining on bond strength to gingival margins of Class II restorations after thermal/mechanical stresses. Proximal cavities were prepared in 90 bovine incisors. Teeth were assigned into nine groups (n = 10), according to the combination of bonding agent [Single Bond (SB), Optibond Solo Plus (OP), Prime & Bond NT (NT)] and layer (1 mm) of flowable composite Filtek Flow (FF) [absent, one layer, two layers]. Materials were applied according to manufacturers' instructions, and FF layers were photoactivated separately. Restorations were concluded with composite resin and were submitted to thermal (1000x, 5-55 degrees C) and mechanical stresses (100,000x, 80 N). For microtensile evaluation, slabs from the gingival bonded interface were obtained, tested under tension, and their failure mode was observed by scanning electron microscopy. Bond strength data were analyzed using two-way ANOVA/Tukey's test. No interaction was observed between adhesive systems and FF lining (p = 0.89). Also, no significant difference was found between bond strength values, whether or not FF layers were used (p = 0.33). However, bonding systems demonstrated significant differences (p = 0.01). SB and NT presented means higher than those observed with OP. Fracture modes varied considerably between experimental groups, and a greater frequency of cohesive failures was noted when FF layers were used.

Influence of thermal and mechanical load cycling on microtensile bond strengths of total and self-etching adhesive systems.

This study evaluated the influence of different thermal (TC) and mechanical (MC) cycling protocols on microtensile bond strength (muTBS) to cervical dentin margins of Class II restorations using two total-etch (TE) adhesives and one self-etching (SE) primer. Class II slot cavities were prepared on the mesial surfaces of 168 bovine incisors and were divided into three groups according to the bonding system used: Single Bond, OptiBond Solo Plus and Clearfil SE Bond. All cavities were restored with Filtek Z250 composite. Following restorative procedures, the restored teeth were allocated to seven subgroups (n = 8) according to the thermal/mechanical protocol performed: G1-control (no cycling), G2-100,000 MC, G3-200,000 MC, G4-500,000 MC, G5-100,000 MC+1,000 TC, G6-200,000 MC+1,000 TC, G7-500,000 MC+1,000 TC. TC was performed using 5 +/- 2 degrees C and 55 +/- 2 degrees C baths, with a dwell time of 60 seconds in each bath. MC was achieved with an axial force of 80 N at 2 cycles/second. The restorations were sectioned perpendicular to the cervical bonded interface into two 0.8-1-mm thick slabs. The slabs were trimmed at the interface to obtain a cross-sectional surface area of 0.8-1 mm2. All specimens were then subjected to muTBS (v = 0.5 mm/minute). Fracture mode analysis was performed using SEM. Bond strength mean values (MPa) were analyzed with ANOVA 3-way and Tukey's test (alpha = 5%). Dunnett's test was used to compare tested groups against Control groups of each adhesive system (alpha = 56%). SE primer presented lower mean bond strength values when compared to TE adhesives (p = 0.05). In addition, specimens restored with the SE primer did not resist to the 200,000 and 500,000 MC associated with TC. The application of 100,000 MC did not present a significant decrease in bond strength when compared to the control. Mixed failures were predominant for all groups. The higher the amount of thermal/mechanical cycles, the greater the number of mixed failures and the lower the percentage of adhesive failures.

The effect of composite type on microhardness when using quartz-tungsten-halogen (QTH) or LED lights.

This study evaluates the Knoop microhardness of resin composites cured with different light-emitting diode (LED) based light curing units (LCU) or with a conventional quartz-tungsten-halogen light (QTH). Ten experimental groups with 10 specimens each were used. The specimens were prepared by placing two light-cured resin composites with similar VITA shade A2-microhybrid Filtek Z250/3M ESPE and microfill Durafil VS/Heraeus Kulzer--in a 2.0 mm-thick disc shaped mold. The specimens were polymerized for 40 seconds with the use of one QTH LCU (Optilux 501/Kerr-Demetron) and four LED LCUs: Elipar FreeLight 1 Cordless LED (3M ESPE), Ultrablue II LED with cord (DMC), Ultrablue III LED cordless (DMC) and LEC 470 I (MM Optics). Knoop microhardness was determined at the top and bottom surfaces of the specimens 24 hours following curing. Microhardness values in the microhybrid resin composite group showed no statistically significant differences when cured with LED FreeLight 1 LCU and QTH LCU (p<0.05). The other LED devices evaluated in the study presented lower microhardness values in both surfaces (p<0.05) when compared to QTH. In the microfill resin composite group, no statistically significant differences were observed among all LCUs evaluated on the bottom surfaces (p<0.05). However, on the top surfaces, QTH presented the highest KHN values, and the LED devices presented similar results when compared with KHN values relative to each other (p<0.05).

Sistemas de pinos intra-radiculares: revisão / lntraradicular post systems: a review

A revisão de literatura apresentada neste artigo mostra uma grande divergência de opiniões relacionadas ao tratamento restaurador de dentes tratados endodonticamente.A utilização de diferentes sistemas de pinos intra-radiculares, com o objetivo de se aumentar a retenção para a coroa protética, é um procedimento indicado para dentes com grande destruição coronária. Assim, diante da grande variedade de pinos pré-fabricados existentes no mercado odontológico e dos diversos fatores que interferem em sua adequada retenção no canal radicular, o propósito deste artigo é discutir e esclarecer eventuais dúvidas relacionadas à escolha de um determinado tipo de pino pré­fabricado, minimizando possíveis riscos de fraturas radiculares

Radiodensity evaluation of seven root post systems.

PURPOSE: To compare through digital radiographic analysis the radiodensity levels of seven prefabricated post systems inserted in root canals of bovine extracted incisors. METHODS: 21 bovine teeth were cut 15 mm from the apical limit. The canals were prepared according to the manufacturer's instructions using specific bur of each post system analyzed: three metallic posts: Flexi-Flange, Radix-Anker, and FKG post; one zirconium ceramic post: Cosmopost; one carbon fiber post: C-Post; one carbon fiber post system covered with quartz fiber: AEsthetic Post; and one glass fiber reinforced post: FibreKor Post. Root tooth digital analyses were made with Digora system with and without the insertion of post. Their variations were obtained subtracting radiodensity of the post from radiodensity of the root canal, in cervical, medium, and apical thirds of the root canal. Two-way ANOVA and Tukey test (P< 0.05) were used to analyze the data. RESULTS: This study showed that the radiopacity of post systems is dependent on their composition. Statistical differences were found among radiodensity levels in apical third, medium and cervical thirds for all post systems inside the root canals. Statistical differences were also found among the post systems: ceramic posts showed the highest radiodensity level, followed by metallic posts, carbon fiber posts, glass fiber posts, and the carbon fiber post covered with quartz fiber. These results indicate that biomechanical post systems have low radiodensity levels.

Effect of different mouthrinses on Knoop hardness of a restorative composite.

PURPOSE: To evaluate the effect of mouthrinses on Knoop hardness number (KHN) of a restorative composite, at different exposure times. METHODS: 50 composite specimens (TPH Spectrum) were randomly allocated into five groups (n=10): distilled water; Listerine; Reach; Plax and Periogard. The samples were immersed daily for 14 days in 20 ml of the respective solution for 2 minutes twice a day (with a 12-hour interval between exposures). Measurements were carried out at four different times: 1 hour after sample preparation, 1, 7 and 14 days after the first immersion in the solutions. RESULTS: Statistical analyses (Repeated Measures ANOVA and Tukey test at 0.05 significance level) showed significant differences among KHN of t wo experimental groups (mean values): Listerine (49.17) and Plax (51.14). There was n ointeraction between products and time, although the highest means were registered 24 hours after the first immersion for all tested groups.

In vitro study of fracture resistance of bovine roots using different intraradicular post systems.

OBJECTIVES: This study evaluated, in vitro, the fracture resistance of bovine roots restored with five different intraradicular post systems. METHOD AND MATERIALS: Seventy-five bovine roots of similar dimensions were assigned to five groups (n = 15), according to the intraradicular post system used: cast post and core; titanium post; carbon-fiber post; glass-fiber post; and zirconium-oxide post. Following post cementation, the roots were embedded in polystyrene resin composite and submitted to fracture-resistance testing, with a compressive load at an angle of 135 degrees in relation to the long axis of the root at a speed of 0.5 mm/min. All data were statistically analyzed with analysis of variance and Sidak test. RESULTS: The titanium posts presented higher mean values of fracture resistance when compared to glass-fiber posts and zirconium-oxide posts and similar values compared to carbon-fiber posts. Also, roots treated with cast posts and cores presented similar results when compared to roots treated with prefabricated posts. CONCLUSION: All prefabricated intraradicular post systems evaluated presented similar resistance to fracture when compared to cast posts and cores, and among the prefabricated ones, titanium and carbon-fiber posts could be best indicated.

Reconstrução de dente anterior fraturado utilizando pino pré-fabricado de fibra de carbono associado à técnica de colagem de fragmento / Reconstruction of a fractured anterior tooth using a prefabricated carbon fiber post associated to the fragment bonding technique

A restauração adequada de dentes anteriores fraturados tem sido uma preocupação constante de Clínicos e Especialistas, pois tais fraturas podem vir a marcar profundamente as pessoas envolvidas, independentemente da idade, do sexo e do nível socioeconômico do paciente. Este artigo vem relatar, através da descrição de caso clínico, um tratamento conservador visando ao aproveitamento do remanescente dental fraturado através da colocação de um pino intraradicular de fibra de carbono, associado à técnica da colagem de fragmento

Influence of load cycling on marginal microleakage with two self-etching and two one-bottle dentin adhesive systems in dentin.

PURPOSE: To evaluate the influence of occlusal load cycling on cervical microleakage of proximal slot restorations located in dentin, using two self-etching and two one-bottle dentin adhesive systems. MATERIALS AND METHODS: 240 proximal slot cavities were prepared in 120 bovine teeth and divided into two groups, one with load cycling and one without. The groups were then subdivided into four subgroups according to the adhesive system used (Experimental EXL 547 Self-etching 3M, Clearfil SE Bond, Single Bond, and Optibond Solo Plus) and restored following the manufacturers' instructions. The teeth were then submitted to mechanical load cycling with a force of 80 N and a frequency of 5 Hz, simultaneously over both restorations of each tooth, for a total of 50,000 cycles per specimen. All specimens were subsequently immersed in a 2% methylene blue solution (pH 7.0), and sectioned to examine the extent of dye penetration under a stereomicroscope (40X). RESULTS: There was no statistically significant difference (p = 0.00002) between the loaded and unloaded teeth. However, a statistically significant difference was observed between the adhesive systems used. The experimental self-etching EXL 547 presented the lowest mean microleakage, but was only statistically significantly different from the Single Bond loaded and unloaded groups and the Clearfil SE Bond unloaded group. CONCLUSION: The application of 50,000 loading cycles did not affect the microleakage of the two self-etching and the two one-bottle adhesive systems evaluated. In vitro mechanical load cycling is an important factor to consider when evaluating the performance of adhesive systems under simulated masticatory conditions.

Facetas diretas em resina composta pós-microabrasão: relato de caso clínico / Composite resin veneer after microabrasion procedure: clinical case report

Este relato de caso clínico tem como objetivo apresentar as etapas clínicas para a tentativa de remoção de manchas de esmalte através da aplicação de um produto microabrasivo, assim como a confecção de facetas diretas em resina composta frente ao insucesso da microabrasão. Após o término do caso, o sorriso do paciente foi restabelecido nos padrões estéticos desejáveis