Effect of S. mutans biofilm on the hybrid ceramic-resin cement bond strength assessed by different methods

Aim: The purpose of this study was to investigate the biofilm effect on the hybrid ceramic-resin cement bond strength (BS) by comparing two methods. Methods: Teeth were distributed into groups (n=5), according to the resin cement (Maxcem Elite-(MC) or NX3 Nexus-(NX)) and degradation method (24h or 7 days in distilled water; 7 or 30 days incubated with biofilm and 30 days in sterile media). Treated surfaces of Vita Enamic blocks (5x6x7mm) were luted to treated or no treated dentin surfaces and light-cured. After 24h, beams were obtained (1x1x10mm) and stored accordingly. The flexural bond strength (FBS) was assessed by four-point bending test. Additional beams were obtained from new teeth (n=5), stored for 24h or 7 days in distilled water, and submitted to a microtensile bond strength (µTBS) assay. Failure modes were determined by scanning electron microscopy (100X). The flexure strength of the cements (n=10) was assessed by a four-point bending test. Data were analyzed by 1 and 2-ways ANOVA, and Tukey's test (α=0.05). Results: There was no significant difference between the degradation methods for the FBS groups. For the µTBS, the significant difference was as follows: NX 7days > NX 24h > MC 7days = MC 24h. Failure mode was mainly adhesive and mixed, but with an increase of cohesive within cement and pre-failures for the MC groups assessed by µTBS. NX had better performance than MC, regardless of the method. Conclusions: The biofilm had no effect on the materials BS and FBS test was a useful method to evaluate BS of materials with poor performance

Fit of metal-ceramic crowns: effect of coping fabrication method and veneering ceramic application

Aim: To evaluate the influence of cobalt-chromium (Co-Cr) coping fabrication methods and ceramic application on the marginal and internal fit of metal-ceramic crowns. Methods: Co-Cr copings for metal-ceramic crowns were prepared by lost wax casting or CAD-CAM machining of sintered blocks. The fit was analyzed using the silicone replica technique at four assessment points: marginal gap (MG), axial wall (AW), axio-occlusal (AO) angle, and central occlusal (CO) wall. After the initial analysis, the copings were ceramic-veneered with the layering technique, and the fit was again determined. Data were statistically analyzed by paired and unpaired Student's-t test (α=0.05). Results: Marginal and internal fit before ceramic application according to the coping manufacturing method showed significant differences only at CO (p < 0.001), with milled copings (137.98±16.71 µm) showing higher gap values than cast copings (112.86±8.57 µm). For cast copings, there were significant differences at MG (before 109.13±8.79 µm; after 102.78±7.18 µm) and CO (before 112.86±8.57 µm; after 104.07±10.63 µm) when comparing the fit before and after ceramic firing. For milled copings, there was significant difference only at AO (before 116.39±9.64 µm; after 108.54±9.26 µm). Conclusion: This study demonstrated that the coping fabrication method influenced the internal fit. Ceramic firing maintained or improved the fit of the metal-ceramic crowns. The marginal discrepancy of all restorations, before and after ceramic firing, can be considered clinically acceptable

Avaliação da sorção e solubilidade de água em cimentos de ionômero de vidro com e sem agente de proteção / Evaluation of water sorption and solubility in glass ionomer cements with and without protective agent

Objetivo: Avaliar o efeito de um protetor de superfície na sorção e solubilidade de cimentos de ionômero de vidro. Materiais e Métodos: Quatro materiais foram selecionados: ionômero modificado por resina encapsulado (Riva Light Cure); modificado por resina pó/líquido (Vitremer); convencional encapsulado (Equia Forte) e convencional pó/líquido (Fuji IX). Foram confeccionados 20 espécimes de cada, sendo metade com proteção superficial do Equia Forte Coat. As amostras foram mantidas em estufa a 37°C em repouso por 5 dias. Em seguida, esses foram pesados em intervalos de 24 horas. A espessura e o diâmetro foram medidos com um paquímetro digital para o cálculo do volume. Novas pesagens foram realizadas para a obtenção da massa intermediária. Em seguida, as amostras foram mantidas em repouso por 5 dias a 37°C e realizada nova pesagem. Resultados: Os dados obtidos de sorção e solubilidade foram submetidos à análise de variância (ANOVA dois fatores, material e protetor de superfície) e teste Tukey ( =0,05). Para sorção, houve diferença significativa apenas para o fator material (p<0,05), Vitremer > Equia Forte > Riva Light Cure > Fuji IX. O ionômero Fuji IX apresentou os menores valores de sorção, diferindo significativamente dos demais materiais, independentemente do uso do protetor superficial. Não houve diferença significativa para o fator proteção de superfície (p>0,05). Para solubilidade não houve diferença significativa no fator material, protetor de superfície ou interação material*protetor. Conclusão: O uso do protetor superficial não influenciou nos valores de sorção e solubilidade dos ionômeros avaliados e o ionômero convencional Fuji IX apresentou menores taxas de sorção.

Objective: evaluate the effect of a surface coating agents on the sorption and glass ionomer cements solubility. Materials and Methods: Four materials were selected: Encapsulated resin-modified ionomer (Riva Light Cure); Powder/liquid Encapsulated resin-modified (Vitremer); Encapsulated conventional (Equia Forte) and powder/ liquid conventional (Fuji IX). Twenty samples of each were made, half with surface protection of Equia Forte Coat. The samples were kept in an oven for 5 days. These were then weighed at 24-hour intervals. The thickness and diameter were measured using a digital caliper to calculate their volume. New weightings were performed to obtain the intermediate mass. Then, the samples were kept at rest for 5 days and weighed again. Results: The sorption and solubility data obtained were subjected to analysis of variance (two-way ANOVA, material and surface coating agents) and Tukey test ( =0.05). For sorption, there was a significant difference only for the material factor (p<0.05), Vitremer > Equia Forte > Riva Light Cure > Fuji IX. The Fuji IX ionomer showed the lowest sorption values, differing significantly from the other materials, regardless of the use of surface coating agents. There was no significant difference for the surface protection factor (p>0.05). For solubility there was no significant difference for the material factor, surface coating agents or material*surface coating agent interaction. Conclusion: The use of surface coating agents did not influence the sorption and solubility values of the evaluated ionomers and the conventional Fuji IX ionomer showed lower sorption rates.

Effect of MDP concentration and addition of iodonium salt on the dentin bond strength of experimental adhesives / Efeito da concentração de MDP e adição de sal de iodônio na resistência de união à dentina de adesivos experimentais

Objetivo: O objetivo foi avaliar a resistência de união de seis adesivos experimentais contendo sistemas fotoiniciadores binários ou ternários, associados a três diferentes concentrações de MDP (0-12% em peso) após 12 meses de armazenamento em água destilada. Material e Métodos: Adesivos experimentais foram preparados com: bis-GMA, UDMA, bis-EMA, TEGDMA, HEMA, BHT e etanol, contendo sistemas fotoiniciadores binários (CQ/amina) ou ternários (CQ/amina/DPIHFP ­ 0,5% em peso). Foi adicionado a esta composição 0%, 6% ou 12% em peso de MDP. Os sistemas adesivos foram aplicados seguindo o protocolo com condicionamento ácido. Moldes cilíndricos transparentes foram colocados sobre a dentina hibridizada, preenchidos com resina composta e fotopolimerizados. Os corpos-de-prova foram armazenados em água destilada a 37oC por 24h ou 12 meses e submetidos ao ensaio de microcisalhamento (n=6). Os dados foram analisados por ANOVA de três fatores e teste de Tukey (α=5%). Resultados: Para o sistema binário, após 12 meses de armazenamento, todos os valores de resistência de união foram semelhantes. Em relação à degradação da resistência de adesão ao longo do tempo, as formulações de MDP de 6% e 12% mostraram resistência de união mais estável do que 0% de MDP. Para o sistema ternário, todas as formulações (0%, 6% e 12% em massa de MDP) mostraram resistência de união estável em função do tempo. Conclusão: Para o sistema binário, as concentrações de 6 e 12% em massa de MDP foram capazes de manter a resistência de união em função do tempo, enquanto que para o sistema ternário, a estabilidade de união foi obtida independentemente da concentração de MDP. Pode-se concluir que, para a formulação dos adesivos utilizados neste estudo, independente do sistema fotoiniciador, a concentração de 12% MDP apresentou valores de resistência de união mais estáveis após 12 meses de armazenamento em água (AU)

Objective: The aim was to evaluate the bond strength of six experimental adhesives containing binary or ternary photoinitiator systems, associated with three different MDP concentrations (0-12wt%) after 12 months of storage in distilled water. Material and Methods: Experimental adhesives were prepared with: bis-GMA, UDMA, bis-EMA, TEGDMA, HEMA, BHT, and ethanol, containing binary (CQ/amine) or ternary (CQ/amine/DPIHFP (diphenyliodonium hexafluorophosphate) ­ 0.5wt%) photoinitiator systems. It was added to this composition 0wt%, 6wt%, or 12wt% of MDP. The adhesive systems were applied following the etch-and-rinse protocol. Transparent cylindrical molds were placed on the hybridized dentin, filled with composite resin and light-cured. The specimens were stored in distilled water at 37oC for 24h or 12 months and submitted to a microshear bond strength test (n=6). Data were analyzed by three-way ANOVA and Tukey's test (α=5%). Results: For the binary system, after 12 months of storage, all bond strength values were similar. Regarding bond strength degradation over time, 6wt% and 12wt% MDP formulations showed more stable bond strength than 0wt% MDP. For the ternary system, all formulations (0wt%, 6wt% and 12wt%) showed stable bond strength over time. Conclusion: For the binary photoinitiator system, the 6wt% and 12wt% MDP concentrations were able to keep bond strength stable over time, while for the ternary system, bond strength stability was achieved regardless the MDP concentration. (AU)

Influence of sonic vibration and cement type on the bond strength of fiberglass posts after aging / Influencia de la vibración sónica y el tipo de cemento en la fuerza de unión de los postes de fibra de vidrio después del envejecimiento

Introduction: This study evaluated the influence of sonic vibration and thermocycling on the bond strength of fiberglass posts using conventional dual-cured and self-adhesive resin cements. Material and Methods: Ninety-six single-rooted endodontically treated teeth were divided randomly into eight groups according to the cement used (dual-cured or self-adhesive resin cement), use of sonic vibration during post accommodation, and aging conditions (24h in distilled water or 5,000 thermal cycles). The fiberglass posts (White Post DC1, FGM) were cleaned with alcohol, treated with silane and cemented with dual-cured (Allcem Core, FGM) or with self-adhesive resin cement (seT, SDI). For groups in which sonic vibration was used, the posts were accommodated, and sonic vibration was applied for 10 s using a special tip placed on top of the post (Sonic Smart Device, FGM). Pull-out tests were performed after storage in distilled water for 24h at 37°C or after thermocycling (5000 cycles, at 5°C and 55°C). The results were evaluated using three-way ANOVA and Tukey's test (α=0.05). Results: Significant differences were not observed between the bond strengths of dual-cured (87.93±41.81 N) and self-adhesive cement (82.53±41.43 N). Bond strength for the sonic vibration groups (100.36±42.35 N) was significantly higher than for groups without sonic vibration (70.13±34.90 N). There were significant differences between specimens subjected to thermocycling (98.33±39.42 N) and those stored for 24h in distilled water (72.16±39.67 N). Conclusion: It can be concluded that both sonic vibration and thermocycling significantly improved bond strength of fiberglass posts with the two evaluated resin cements.

Introducción: Este estudio evaluó la influencia de la vibración sónica y el termociclado en la fuerza de unión de los postes de fibra de vidrio utilizando cementos de resina autoadhesivos y de curado dual convencionales Material y Métodos: Se dividieron aleatoriamente noventa y seis dientes tratados endodónticamente de raíz única en ocho grupos según el cemento utilizado (cemento de resina de curado dual o autoadhesivo), el uso de vibración sónica durante la acomodación posterior y las condiciones de envejecimiento (24 horas agua destilada o 5.000 ciclos térmicos). Los postes de fibra de vidrio (White Post DC1, FGM) se limpiaron con alcohol, se trataron con silano y se cementaron con cemento de curado dual (Allcem Core, FGM) o con cemento de resina autoadhesivo (seT, SDI). Para los grupos en los que se utilizó vibración sónica, se acomodaron los postes y se aplicó la vibración sónica durante 10 s utilizando una punta especial colocada en la parte superior del poste (Sonic Smart Device, FGM). Las pruebas de extracción se realizaron después del almacenamiento en agua destilada durante 24 horas a 37ºC o después del termociclado (5000 ciclos, a 5ºC y 55ºC). Los resultados se evaluaron mediante ANOVA de tres vías y la prueba de Tukey (α = 0.05). Resultados: No se observaron diferencias significativas entre las resistencias de adhesión del cemento de curado dual (87,93 ± 41,81 N) y el cemento autoadhesivo (82,53 ± 41,43 N). La fuerza de unión para los grupos de vibración sónica (100,36 ± 42,35 N) fue significativamente mayor que para los grupos sin vibración sónica (70,13 ± 34,90 N). Hubo diferencias significativas entre los especímenes sometidos a termociclado (98,33 ± 39,42 N) y los almacenados durante 24 h en agua destilada (72,16 ± 39,67 N). Conclusión: Se puede concluir que tanto la vibración sónica como el termociclado mejoraron significativamente la fuerza de unión de los postes de fibra de vidrio con los dos cementos de resina evaluados.

Surface deterioration of indirect restorative materials

Abstract The objective of this work was to evaluate the effects of in vitro and in situ biodegradation on the surface characteristics of two resin cements and a hybrid ceramic system. One hundred and eighty specimens (4X1.5mm) of each material (Maxcem Elite, NX3 Nexus and Vita Enamic) were made and randomly distributed in twelve groups (n=15) according to the material and biodegradation method. The specimens were then submitted to the following challenges: storage in distilled water 37 ºC for 24 h or 7 days, storage for 7 days, at 37 ºC, in stimulated saliva or in situ. The in situ stage corresponded to the preparation of 15 intraoral palatal devices, used for 7 days. Each device presented 3 niches, where a sample of each materials was accommodated. Specimens from both saliva and in situ groups suffered a cariogenic challenge, corresponding to the application of a solution of 20% of sucrose, 10 times throughout each day. After each biodegradation method, the surface roughness (Ra), Vickers hardness (VHN) and scanning electron microscopy (SEM) analyzes were performed. The data collected were evaluated by Levene test, two-way ANOVA and Tukey`s test (α=5%). The in situ challenge promoted the greater biodegradation, regardless of the material. Regarding the materials, the Vita Enamic VHN was negatively affected by all biodegradation methods and the Nexus NX3 presented better performance than the self-adhesive cement tested. Therefore, within the conditions of this work, it was concluded that in situ biodegradation can affect negatively the surface characteristics of indirect restorative materials.

Resumo O objetivo deste trabalho foi avaliar os efeitos da biodegradação in vitro e in situ nas características superficiais de dois cimentos resinosos e de um sistema cerâmico híbrido. Cento e oitenta espécimes (4X1,5mm) de cada material (Maxcem Elite, NX3 Nexus e Vita Enamic) foram distribuídos aleatoriamente em doze grupos (n=15) de acordo com o material e o método de biodegradação. Os espécimes foram então submetidos aos seguintes desafios: armazenamento em água destilada 37ºC por 24 horas ou 7 dias, armazenamento por 7 dias, a 37ºC, em saliva estimulada ou in situ. O estágio in situ correspondeu à preparação de 15 dispositivos intra-orais palatinos, utilizados por 7 dias. Cada dispositivo apresentou 3 nichos, onde uma amostra de cada material foi acomodada. As amostras dos grupos saliva e in situ sofreram um desafio cariogênico, correspondendo à aplicação de uma solução de 20% de sacarose, 10 vezes ao longo de cada dia. Após cada método de biodegradação, foram realizadas as análises de rugosidade superficial (Ra), dureza Vickers (VHN) e microscopia eletrônica de varredura (MEV). Os dados coletados foram analisados por meio do teste de Levene, ANOVA two-way e teste de Tukey (α=5%). O desafio in situ promoveu maior degradação, independentemente do material. Em relação aos materiais, a VHN do Vita Enamic foi afetada negativamente por todos os métodos de degradação e o Nexus NX3 apresentou melhor desempenho que o cimento autoadesivo testado. Portanto, dentro das condições deste trabalho, concluiu-se que a biodegradação in situ pode afetar negativamente as características superficiais de materiais restauradores indiretos.

Influence of acidic monomer concentration and application mode on the bond strength of experimental adhesives

Abstract The aim of this research was to evaluate the influence of MDP (10-methacryloyloxydecyl dihydrogen phosphate) concentration and application mode of experimental adhesives on microshear bond strength (μSBS) to dentin after storage in distilled water at 37°C for 24h and 6 months. Five experimental adhesives were prepared with: CQ, DABE, BHT, ethanol, HEMA, TEGDMA, Bis-EMA, UDMA, and Bis-GMA. Concentrations of 0 wt%, 3 wt%, 9 wt%, 12 wt% or 15 wt% of MDP were added to their composition. The adhesives were applied to flat dentin surfaces in etch-and-rinse or self-etching modes. Cylindrical molds filled with light-cured composite resin were placed above the dentin. The specimens were stored in distilled water at 37oC for 24h or 6 months and submitted to μSBS testing. The adhesives were also submitted to pH analysis. The data were analyzed by one-way ANOVA, three-way ANOVA and Tukey's test (α = 5%). All the adhesives used in the etch-and-rinse mode showed significantly higher bond strength than the adhesives applied in the self-etching approach. The 9 wt% adhesive showed the highest bond strength values, and 3 wt% was most stable after storage. A strong negative correlation between MDP concentration and pH was observed. It was concluded that the formulations with low concentrations of MDP (up to 9 wt%) showed better results for bond strength and bond strength degradation over time.

Long-term color stability of orthodontic adhesives after exposure to different staining agents

Context: The aims of this study were (i) to evaluate the color stability of two orthodontic adhesives and (ii) to evaluate the color stability of enamel and ceramic brackets bonded with orthodontic adhesives after exposure to different staining agents. Materials and Methods: Disks were prepared with two orthodontic adhesives (Transbond and Enlight). Color stability evaluation was performed with a spectrophotometer using CIELab parameters. The specimens were divided into four groups and immersed in the following staining agents (n = 5): distilled water (control), coffee, red wine, and cola soft drink, for 1 h/day for 120 days. Twenty molar crowns were also used. The baseline color of enamel was obtained and ceramic brackets were bonded with the orthodontic adhesives. The enamel specimens were divided into four groups and immersed in the same staining agents. After 120 days, another color reading with the brackets in position was taken. The brackets were then removed and the enamel color was again evaluated. Color difference (ΔE) in different time periods was determined and the data were analyzed by ANOVA and Tukey's test (α = 5%). Results: Transbond showed lower ΔE than Enlight. Water, cola, and coffee had the lowest ΔE values. Immersion in wine showed the highest ΔE values. For time, the lower ΔE values were found for 24 h and 7 days. Storage times of 60, 90, and 120 days showed the highest ΔE values. ΔE for enamel showed significant differences only for time. Conclusion: Adhesive, staining agents, and storage time influenced the color stability of orthodontic adhesives.

Influence of pre-curing different adhesives on the color stability of cemented thin ceramic veneers

Abstract The objective was to evaluate the color stability of thin ceramic veneers as a function of the curing mode (with and without pre-cure) of different adhesive systems applied to the internal surface of ceramics. Five adhesive systems (Scotchbond Multi-Purpose, Single Bond Universal, Gluma 2 Bond, Ambar, and Ambar APS) and photo-cured resin cement (Allcem Veneer) were used for cementing 0.6 mm-thick feldspathic veneers (Mark II) on composite resin substrates (Charisma Diamond). The groups, according to adhesive system, were divided into two subgroups (n=10): i) adhesive and resin cement were polymerized separately (pre-cure of the adhesive), ii) adhesive and resin cement were polymerized simultaneously. The CIELab color parameters were determined with a spectrophotometer at 24h (baseline), 7 days, 30 days and 12 months. Data were analyzed by two-way ANOVA and Tukey's test (α=0.05). The results indicated statistically significant differences for adhesive systems and time. The mode of curing of the adhesive system was not statistically significant: pre-cured adhesives (2.6±1.3) and not pre-cured adhesives (2.8±1.4). For the adhesives, ΔE values varied in the following order: Ambar-APS (1.6±0.5) < Scotchbond Multi-Purpose (2.6±1.2) = Gluma 2 Bond (2.7±1.2) = Ambar (2.9±1.2) < Single Bond Universal (3.5±1.5). For time, ΔE values were: 7 days (1.7±0.7), 30 days (3.5±1.2) and 12 months (2.9±1.3). It can be concluded that the different adhesive systems used for cementing thin ceramic veneers influenced the final color of the indirect restorations. The adhesives curing mode did not present a significant effect in the color stability of thin ceramic veneers.

Resumo O objetivo deste estudo foi avaliar a estabilidade de cor de laminados cerâmicos de espessura fina em função do momento de ativação de diferentes sistemas adesivos na superfície interna das cerâmicas. Foram utilizados 5 sistemas adesivos (Scotchbond Multiuso, Single Bond Universal, Gluma 2 Bond, Ambar and Ambar APS) e o cimento resinoso fotoativado (Allcem Veneer) para cimentação de lâminas de cerâmica feldspática (Mark II) com 0,6 mm de espessura, sobre substratos de resina composta (Charisma Diamond). Os grupos, de acordo com o sistema adesivo utilizado, foram divididos em dois subgrupos (n=10): i) adesivo e cimento resinoso foram polimerizados separadamente (polimerização isolada do adesivo), ii) adesivo e cimento resinoso foram polimerizados ao mesmo tempo (polimerização simultânea). Os parâmetros de cor do sistema CIELab foram determinados com um espectrofotômetro nos tempos de 24 h (baseline), 7 dias, 30 dias e 12 meses. Os dados foram analisados por ANOVA a dois fatores e teste de Tukey (α=0,05). Os resultados indicaram diferenças estatísticas significantes para os sistemas adesivos e tempo. O momento da fotoativação do sistema adesivo não foi estatisticamente significante: polimerização prévia (2,6±1,3) e polimerização simultânea (2,8±1,4). Para o sistema adesivo, os valores médios de ΔE variaram na seguinte ordem: Ambar APS (1,6±0,5)<Scotchbond Multi-Purpose (2,6±1,2)=Gluma 2 Bond (2,7±1,2)=Ambar (2,9±1,2)<Single Bond Universal (3,5±1,5). Para o fator tempo o ΔE foi: 7 dias (1,7±0,7), 30 dias (3,5±1,2) e 12 meses (2,9±1,3). Pode-se concluir que os diferentes sistemas adesivos utilizados na cimentação de laminados cerâmicos de espessura fina influenciaram na cor final das restaurações. O momento da fotoativação, isolada ou simultânea ao cimento resinoso, não apresentou efeito significativo na estabilidade de cor dos laminados cerâmicos de espessura fina.

Physicomechanical properties of different nanohybrid composites after aging: color stability, flexural strength, and microhardness

Aim: To evaluate the physicomechanical properties of different hybrid composites (Charisma Diamond - CD, Aura - AU, NT Premium - NT, Opallis - OP, Filtek Z250 ­ Z250) after 6 months of aging in distilled water. Methods: Discs were fabricated and color measurements were performed after 24 hours and at 7, 30, and 180 days. Flexural strength was determined using the three-point bending test. For the microhardness test, the specimens were flattened to obtain polished and flat surfaces and indentations. The results for ∆E and microhardness were analyzed by two-way repeated-measures ANOVA and Tukey's HSD test. The flexural strength results were analyzed by two-way ANOVA and Tukey's test (α=0.05). Results: The ∆E values for composite resins varied in the following order: CD (3.54)a < Z250 (4.70)ab < AU (4.95)ab < OP (5.20)ab < NT (6.23)b. ∆E values were lower for 24 h (3.84)a < 7 days (4.43)ab < 30 days (4.93)b. The highest values were observed after 180 days (ΔE = 6.54)c. The flexural strength of composite resins varied in the following order: CD (89.17 MPa)a < Z250 (73.06 MPa)b < OP (60.30 MPa)c < NT (51.28 MPa)c < AU (23.77 MPa)d. Flexural strength values were significantly higher for 24 h (68.62 MPa)a < 180 days (51.40 MPa)b. The microhardness of composite resins varied in the following order: Z250 (112.05)a < CD (102.15)ab < OP (92.04)bc < NT (87.77)d < AU (87.68)d. Microhardness was significantly higher for 180 days (113.44)a < 24 h (78.21)b. Conclusion: The microhybrid (Z250) and one of the nanohybrid composites (CD) performed better. The color stability and flexural strength of all tested composites decreased with storage time

Twenty-year clinical experience with fixed functional appliances

ABSTRACT Introduction: Considering the large number of fixed functional appliances, choosing the best device for your patient is not an easy task. Objective: To describe the development of fixed functional appliances as well as our 20-year experience working with them. Methods: Fixed functional appliances are grouped into flexible, rigid and hybrid. They are different appliances, whose action is described here. Four clinical cases will be reported with a view to illustrating the different appliances. Conclusions: Rigid fixed functional appliances provide better skeletal results than flexible and hybrid ones. Flexible and hybrid appliances have similar effects to those produced by Class II elastics. They ultimately correct Class II with dentoalveolar changes. From a biomechanical standpoint, fixed functional appliances are more recommended to treat Class II in dolichofacial patients, in comparison to Class II elastics.

RESUMO Introdução: considerando-se o grande número de aparelhos propulsores mandibulares, não é uma tarefa fácil escolher o melhor deles para o seu paciente. Objetivo: descrever o desenvolvimento desses aparelhos e a experiência clínica de vinte anos dos autores na sua utilização. Métodos: os aparelhos funcionais fixos aqui apresentados foram classificados em flexíveis, rígidos e híbridos, e o modo de ação de cada um deles foi descrito e ilustrado por meio de quatro casos clínicos. Conclusões: os aparelhos propulsores rígidos fornecem mais resultados esqueléticos do que os flexíveis e os híbridos. Esses últimos têm efeito semelhante ao uso de elásticos com direção de Classe II e, basicamente, corrigem a má oclusão de Classe II com alterações dentoalveolares. Do ponto de vista biomecânico, os propulsores fixos estão mais indicados para tratar a Classe II em pacientes dolicofaciais do que os elásticos de Classe II.

Efeito de diferentes métodos de remoção de remanescente adesivo na rugosidade superficial do esmalte após descolagem de bráquetes / Effect of different methods of adhesive remaining removal on enamel surface roughness after bracket debonding

O objetivo deste estudo foi comparar diferentes métodos de remoção do remanescente adesivo após a descolagem de bráquetes em relação à rugosidade superficial do esmalte. Trinta pré-molares com superfície lingual íntegra e sem fraturas foram selecionados. Os dentes foram submetidos à profilaxia com pasta de pedra-pomes e água e fixados individualmente com auxílio de uma morsa à bancada de trabalho. A rugosidade superficial de cada espécime foi medida com auxílio de um rugosímetro. Foram efetuadas três leituras em posições diferentes e a média das leituras foi utilizada. Após a leitura inicial os bráquetes foram colados utilizando a resina Transbond XT, de acordo com as instruções do fabricante. Os espécimes foram armazenados em estufa a 37ºC e 100% de umidade por 24hs. Depois os bráquetes foram removidos e os espécimes foram aleatoriamente distribuídos em 3 grupos (n=10) de acordo com o sistema utilizado para remoção do remanescente adesivo: broca multilaminada 12 lâminas (Jet), pontas de óxido de alumínio (DHPRO) e pontas de fibra de vidro (Fiberglass). Uma segunda leitura de rugosidade foi realizada, seguindo os mesmos parâmetros descritos. Em seguida, os espécimes foram submetidos ao polimento com pasta de pedra-pomes e água e uma terceira leitura foi realizada. Os dados foram submetidos à análise estatística (ANOVA p<0,05). Não houve diferença estatística significativa nos valores de rugosidade superficial entre os grupos (p>0,05), independentemente do momento de avaliação. Conclui-se que os métodos avaliados não interferiram na rugosidade superficial do esmalte, sendo seguros para utilização na remoção do remanescente adesivo. (AU)

The objective of this study was to compare different methods of remaining adhesive removal after bracket debonding in relation to enamel surface roughness. Thirty premolars with intact lingual surface without fractures were selected. The teeth were submitted to prophylaxis with pumice paste and water and then set individually with the aid of a vise to the workbench. Surface roughness of each specimen was measured by a roughness meter. Three readings were performed in different positions and readings average was used as the roughness value for each specimen. After the initial reading brackets were bonded using the Transbond XT resin, according to the manufacturer's instructions. The specimens were stored at 37°C and 100% humidity for 24 hours. After the brackets were removed, the specimens were randomly divided into 3 groups (n=10) according to the system used to remove the remaining adhesive (laminated drill ­ Jet, aluminum oxide tips ­ DHPRO and fiberglass tips ­ Fiberglass). A second roughness reading was performed following the same parameters described. Then the specimens were polished with pumice paste and water and a third reading was performed. Data was subjected to statistical analysis (ANOVA p<0.05). No statistically significant differences in surface roughness values was found among the groups (p>0.05), regardless of evaluation time. It can be concluded that the methods evaluated did not affect the enamel surface roughness and are safe for use when removing the remaining adhesive.(AU)

Surface topography and bacterial adhesion of CAD/CAM resin based materials after application of different surface finishing techniques

Aim: This study evaluated the surface topography and bacterial adhesion of a hybrid ceramic and a nano ceramic resin composite after different surface finishes. Methods: Hybrid ceramic (Vita Enamic, VITA - EN) and nano ceramic resin composite (Lava Ultimate, 3M/ESPE - LV) blocks of 12 x 14 x 18 mm were cut into 1 mm slices. Each slice was divided into four specimens (6 x 7 mm) that were randomly allocated into 4 groups (n=8) according to the surface finishing: CTL - without surface finish (control); DB - wear with a diamond bur; VT - polishing system for hybrid ceramic (VITA); and DD - polishing system for ceramics (Dedeco). The specimens were analyzed regarding surface roughness parameters (Ra, Rz, Rq), sterilized and subjected to bacterial adhesion. Representative specimens from each group were observed by SEM and Confocal Laser Scanning Microscopy. Data were submitted to two-way ANOVA and Tukey's test (α=0.05). Results: EN had lower surface roughness and bacterial adhesion than LV (p<0.05), regardless of the surface finish. The highest values for all roughness parameters was observed in LVDB group, differing from the other groups, which were not significantly different. Smaller bacterial adhesion values (CFU/mL) were observed for ENDD and ENVT, which differed significantly from the other groups, except ENCTL. For LV groups there was no significant difference between the different surface finishes (p>0.05). The type of material and surface finish system significantly interfered with surface roughness parameters and bacterial adhesion. The hybrid ceramic performed better after polishing than the nano-ceramic resin. Conclusion: An adequate finishing/polishing technique should always be performed after any kind of adjustment to indirect restorations made with these materials tested

Effect of hydrogen peroxide and universal adhesive application on the bond strength of glass fiber posts

Aim: This study aims to evaluate the effect of different surface treatments on the bond strength of glass fiber posts. Methods: Ninety unirradicular premolars had their crowns removed and were endodontically treated. After 24h, post spaces were prepared and the roots (n=15) were divided into six groups according to the post surface treatment: NT ­ no treatment, UA ­ universal adhesive (Single Bond Universal), SUA ­ silane (Prosil), followed by universal adhesive, H ­ H2O2 (Whitness HP Maxx, 35%, gel, 1 min), HUA ­ H2O2, followed by universal adhesive, and HSUA ­ H2O2, followed by silane and universal adhesive. The posts were cemented with dual-cured resin cement (RelyX Ultimate). Bond strength was evaluated with pull-out test (0.5 mm/mim) after 24h-storage in distilled water at 37oC. Data were submitted to ANOVA and Tukey's test (α=5%). Results: HSUA group showed the highest bond strength value (236.5 N) followed by HUA (206.5 N), NT (194 N) and SUA (184 N) groups. UA group showed the lowest bond strength value (60 N). Conclusion: The use of H2O2, the silane application or the combination of these two treatments significantly increased bond strength values in groups in which the universal adhesive was used. A simplified procedure, such as cleaning with alcohol, can be recommended as surface treatment for the cementation of glass fiber posts (AU)

Physical properties of two bis-acryl interim materials: color stability, flexural strength and shear bond strength to flowable composite resin as add-on material

Aims: The objective of this study was to evaluate the mechanical properties of two bis-acryl interim resin materials, such as color stability, flexural strength and shear bond strength to flowable composite resin, simulating clinical situations when this material has to be used for repair as add-on. Two shades of two bis-acryl interim resin materials [Structur 2 SC (shades Bleach and A2); Protemp 4 (shades A1 and A2)] were evaluated. Discs (5 x 1 mm) were fabricated and baseline color was determined after 1 h. Ten specimens were immersed at 37oC in solutions of distilled water (control) and cola-based soft drink (Coca-Cola). Color measurements were performed with a spectrophotometer using CIELab parameters. Color readings were again measured after 2 hours, 4 hours, 24 hours and 7 days. Flexural strength was determined using the three-point bending test (10 x 1 x 2 mm) on a universal testing machine (0.5 mm/min) (n = 10). Discs of bis-acryl resin were embedded in acrylic resin, planned and distributed in 2 groups: G1 - Filtek Z350 Flow/Protemp4 and G2 - Grandio SO Flow/Structure 3 (n = 15). Cylinders (3.5 x 2 mm) were made with the flowable composite resins and polymerized for 20 s. The specimens were stored in distilled water at 37oC for 24 h and subjected to shear bond strength test. Data were analyzed using one-way ANOVA and Tukey's test (α = 0.05). ΔE values were higher for Structur Bleach (3.08)a compared with Protemp 4 (shade A1, 2.22)b (shade A2, 2.25)b. There were no significant differences between Structur Bleach and Structur A2 (2.62)ab. Coca-Cola presented higher ΔE values (3.08)a than (2.00)b. Regarding time, ΔE values increased from 1.84a after 2 h to 2.31b after 4 h. The higher values were observed after 24 h and 7 days (2.93c and 3.09d, respectively). No significant differences were observed for the flexural strength of Structur (22.05 MPa)a and Protemp 4 (19.01 MPa)a. The repairs executed with Structur/Grandio flow (9.21 MPa)a were similar to those performed with Protemp 4/Z350XT flow (10.71 MPa)a. It can be concluded that the two bis-acyl resins evaluated showed similar physical and mechanical properties (AU)

Marginal and Internal Adaptation of Zirconia Crowns: A Comparative Study of Assessment Methods

Abstract Marginal and internal adaptation is critical for the success of indirect restorations. New imaging systems make it possible to evaluate these parameters with precision and non-destructively. This study evaluated the marginal and internal adaptation of zirconia copings fabricated with two different systems using both silicone replica and microcomputed tomography (micro-CT) assessment methods. A metal master model, representing a preparation for an all-ceramic full crown, was digitally scanned and polycrystalline zirconia copings were fabricated with either Ceramill Zi (Amann-Girrbach) or inCoris Zi (Dentslpy-Sirona), n=10. For each coping, marginal and internal gaps were evaluated by silicone replica and micro-CT assessment methods. Four assessment points of each replica cross-section and micro-CT image were evaluated using imaging software: marginal gap (MG), axial wall (AW), axio-occlusal angle (AO) and mid-occlusal wall (MO). Data were statistically analyzed by factorial ANOVA and Tukey test (a=0.05). There was no statistically significant difference between the methods for MG and AW. For AO, there were significant differences between methods for Amann copings, while for Dentsply-Sirona copings similar values were observed. For MO, both methods presented statistically significant differences. A positive correlation was observed determined by the two assessment methods for MG values. In conclusion, the assessment method influenced the evaluation of marginal and internal adaptation of zirconia copings. Micro-CT showed lower marginal and internal gap values when compared to the silicone replica technique, although the difference was not always statistically significant. Marginal gap and axial wall assessment points showed the lower gap values, regardless of ceramic system and assessment method used.

Resumo A adaptação marginal e interna é fundamental para o sucesso das restaurações indiretas e novos sistemas de imagem permitem avaliar esses parâmetros de maneira não-destrutiva e com precisão. Este estudo avaliou a adaptação marginal e interna de copings de zircônia fabricados com dois sistemas diferentes, utilizando as técnicas da réplica em silicone e micro-CT. Um modelo-mestre de metal, representando um preparo para uma coroa totalmente cerâmica foi digitalizado e copings de zirconia policristalina (Ceramill Zi, Amann Girrbach e inCoris Zi, Dentslpy Sirona, n=10) foram fabricados. Para cada coping, a adaptação marginal e interna foi avaliada pelas técnicas da réplica em silicone e micro-CT. Foram avaliados quatro pontos de cada seção transversal e imagem de micro-CT: adaptação marginal (MG), parede axial (AW), ângulo axial-oclusal (AO) e parede centro-oclusal (MO) utilizando um software de imagem. Os dados foram analisados estatisticamente por ANOVA e teste de Tukey (a=0,05). Não houve diferença estatisticamente significativa entre as duas técnicas para MG e AW. Para AO, houve diferenças significativas entre as técnicas para copings da Amann, enquanto que para copings da Dentsply Sirona foram observados valores semelhantes. Para o MO, ambas as técnicas apresentaram diferenças estatisticamente significativas. Observou-se uma correlação positiva entre os valores de adaptação determinados pelas duas técnicas. O método de avaliação influenciou a avaliação da adaptação marginal e interna de copings de zircônia. Pode-se concluir que a micro-CT mostrou menores valores de adaptação marginal e interna quando comparado com a técnica de réplica em silicone. Os pontos de avaliação da margem e da parede axial mostraram os menores valores de adaptação, independente do sistema cerâmico e da técnica de avaliação utilizados.

Ortodontia lingual x alinhadores removíveis: quando utilizar / Lingual orthodontics x removable aligners: when to use

A Ortodontia está passando por uma nova fase. Muitos pacientes adultos estão buscando o tratamento atualmente e não querem usar um aparelho convencional. Isso tem feito com que a Ortodontia desenvolva novos métodos de tratamento mais estéticos e também aprimore os já existentes. Duas modalidades de tratamento têm ganhado muito destaque nos últimos anos: a Ortodontia Lingual e os Alinhadores Removíveis. O objetivo deste artigo é descrever a técnica lingual Harmony e os alinhadores removíveis Essix e Clear Aligner, comparando-os e mostrando o tratamento de dois casos clínicos. Para o caso tratado com a técnica Lingual foi escolhido o aparelho Harmony devido à necessidade de grande controle de torque nos incisivos superiores. O caso tratado com alinhadores era um caso simples de recidiva pós-tratamento ortodôntico. Os casos clínicos descritos evidenciaram o papel importante que as novas modalidades de tratamento estético podem ter na Ortodontia contemporânea. Cabe ao ortodontista clínico conhecer essas ferramentas e as utilizar nos casos apropriados.(AU)

Orthodontics is going through a new phase. Many adult patients are currently seeking treatment and do not want to use a conventional device. This has led Orthodontics to develop new aesthetic treatment methods, as well as to improve existing ones. Two treatment modalities have gained much prominence in recent years: Lingual Orthodontics and Removable Aligners. The purpose of this article isx to describe the Harmony lingual technique and the Essix and Clear Aligner removable aligners, comparing them and showing the treatment of two clinical cases. For the case treated with the lingual technique, the Harmony device was chosen due to the need for great torque control in the upper incisors. The case treated with aligners was a simple case of orthodontic posttreatment relapse. The clinical cases described evidenced the important role that the new modalities of aesthetic treatment can have in contemporary Orthodontics. It is up to the clinical orthodontist to know these tools and use them in appropriate clinical cases.(AU)

Correção da má oclusão de Classe II assimétrica utilizando ancoragem absoluta / Asymmetrical Class II malocclusion correction using absolute anchorage

Objective: To evaluate the shear bond strength of passive self-ligating brackets (Tellus EX, Eurodonto) fixed to enamel using different materials and adhesive protocols. Materials and methods: Forty-eight bovine incisors were selected and divided into 6 groups according to the material and the adhesive protocol, as follows: G1 - Orthodontic resin Transbond XT, 3M Unitek (TB) associated to Single Bond 2 adhesive, 3M ESPE (SB2), G2 - TB associated with Ambar adhesive, FGM (AB), G3 - TB without application of adhesive, G4 - Orthodontic resin Orthocem, FGM (OC) associated with SB2, G5 - OC associated with AB and G6 - OC without adhesive application. The brackets were fixed following the manufacturers' instructions and stored in deionized water at 37°C for 24h. After that, the specimens were subjected to shear bond strength test (SBS) in a universal test machine (DL2000, Emic) with a crosshead speed of 0.5 mm/min and evaluated for adhesive remnant index (ARI). The data were submitted to ANOVA two criteria and Tukey's test (α = 0.05). Results: There was statistically significant difference between groups (p<0.05). The combination TB/SB2 (G1) showed significantly higher SBS values than TB/without adhesive (G3) and OC/SB2 (G4), not differing from the other groups. The lowest SBS values were observed for the TB group/without adhesive (G3), which did not differ from OC/SB2 groups (G4) and OC/without adhesive (G6). Conclusion: The use of adhesives before application of orthodontic resin promotes improvement in SBS values, except for the OC material, which can be used without adhesive association, without a significant adhesion reduction.(AU)

Objetivo: Avaliar a resistência de união ao cisalhamento de bráquetes autoligados passivos (Tellus EX, Eurodonto), fixados com diferentes materiais e protocolos adesivos. Material e metódos: Quarenta e oito incisivos bovinos foram selecionados e distribuídos em 6 grupos de acordo com o material e o protocolo adesivo, sendo: G1 - resina ortodôntica Transbond XT, 3M Unitek (TB) associada ao adesivo Single Bond 2, 3M ESPE (SB2), G2 - TB associado ao adesivo Ambar, FGM (AB), G3 - TB sem aplicação de adesivo, G4 - resina ortodôntica Orthocem, FGM (OC) associada a SB2, G5 - OC associado a AB e G6 - OC sem aplicação de adesivo. Os bráquetes foram fixados seguindo as instruções dos fabricantes e armazenados em água deionizada a 37ºC por 24h. Depois, os espécimes foram submetidos ao ensaio de resistência de união cisalhamento (RU) em máquina de ensaio universal (DL2000, Emic) à velocidade de 0,5 mm/min e avaliados quanto ao índice de remanescente adesivo (IRA). Os dados foram submetidos à análise de variância dois critérios e teste de Tukey (α=0,05). Resultados: Houve diferença estatística significativa entre os grupos (p<0,05). A combinação TB/SB2 (G1) apresentou significativamente maiores valores de RU do que TB/sem adesivo (G3) e OC/SB2 (G4), não diferindo dos demais grupos. Os menores valores RU foram observados para o grupo TB/sem adesivo (G3), o qual não diferiu dos grupos OC/SB2 (G4) e OC/sem adesivo (G6). Conclusão: O uso de adesivos antes da aplicação da resina ortodôntica promove melhora nos valores de RU, exceto para o material OC, o qual pode ser utilizado sem associação a adesivo, sem que haja redução significativa da adesão.(AU)

Effect of Enamel and Dentin Surface Treatment on the Self-Adhesive Resin Cement Bond Strength

Abstract The aim of this study was to evaluate the effect of enamel and dentin surface treatment on the micro-shear bond strength of self-adhesive cement. Seventy-two extracted third molars had their crowns embedded in acrylic resin and worn to obtain a flat enamel or dentin surface. The enamel and dentin specimens were randomly assigned to 8 groups (n=12) that were based on surface treatment (11.5% polyacrylic acid solution or no treatment), substrate condition (wet or dry) and storage period (1 day or 90 days), and treated accordingly. Cylinders (1 × 1 mm) were fabricated using self-adhesive resin cement (RelyX U200) following the manufacturer's instructions. The specimens were stored in distilled water at 37 °C for either 1 day or 90 days and subjected to micro-shear bond strength test (EMIC DL 2000 at 0.5 mm/min). After this, the failure type of the specimens was determined. Data were subjected to statistical analysis (a=0.05). According to the results, the 11.5% polyacrylic acid application decreased the bond strength in both enamel and dentin samples. The moist groups showed higher bond strength than the dry ones, regardless of the substrate and surface treatment. Storage period did not influence bond strength. In conclusion, surface treatment with 11.5% polyacrylic acid and absence of moisture decreased the bond strength of the resin-cement (RelyU200), regardless of the storage period.

Resumo O objetivo do estudo foi avaliar o efeito de tratamentos de superfície em esmalte e dentina na resistência de união (RU) de um cimento auto-adesivo. As coroas de setenta e dois terceiros-molares foram incluídas em resina acrílica e desgastadas para obtenção de áreas planas em esmalte e dentina. Os espécimes de esmalte e dentina foram aleatoriamente distribuídos em 8 grupos (n=12) de acordo com: tratamento de superfície (sem tratamento ou aplicação de solução de ácido poliacrílico a 11,5%), condição do substrato (seco ou úmido) e período de armazenamento (1 dia ou 90 dias). Após, cilindros (1 x 1 mm) foram confeccionados na superfície dos espécimes utilizando cimento resinoso auto-adesivo (Rely X U200) segundo as instruções do fabricante. Os espécimes foram armazenados em água destilada a 37 oC por 1 dia ou 90 dias e submetidos ao ensaio mecânico de microcisalhamento (EMIC DL 2000 a 0,5 mm/min). O tipo de falha de cada espécime foi determinado após ensaio. Os dados foram submetidos à análise estatística (a=0,05). De acordo com os resultados, a aplicação de ácido poliacrílico a 11,5% diminuiu a RU em ambos substratos, esmalte e dentina. Os grupos mantidos úmidos mostraram maiores valores de RU do que os secos, independentemente do substrato ou tratamento de superfície. O período de armazenamento não influenciou nos valores de RU. Concluiu-se que o tratamento de superfície com ácido poliacrílico a 11,5% e a ausência de umidade no substrato diminuíram os valores de RU para o cimento resinoso auto-adesivo, independentemente do período de armazenamento.

Influence of the Resin Cement Thickness on the Push-Out Bond Strength of Glass Fiber Posts

Abstract The objective of the present study was to evaluate the influence of resin cement thickness on the bond strength of prefabricated and customized glass fiber posts after storage in distilled water. Thirty human uniradicular roots were treated endodontically. The roots were divided into 3 groups: THIN (thin cement layer) - post space preparation with #0.5 drill and cementation of #0.5 post; THICK (thick cement layer) - post space preparation with #1 drill and cementation of #0.5 post; and CUSTOM (customized cement layer) - post space preparation with #1 drill and cementation of a customized post (#0.5 glass fiber posts customized with resin composite). All posts were luted with self-adhesive resin cement. The push-out test was carried out after storage for 24 h and 90 days in distilled water at 37 °C. The data were analyzed with three-way ANOVA and Tukey's test (a=0.05). Bond strengths were significantly higher for CUSTOM (9.37 MPa), than for THIN (7.85 MPa) and THICK (7.07 MPa), which were statistically similar. Considering the thirds, the bond strength varied in the sequence: apical (7.13 MPa) < middle (8.22 MPa) = coronal (8.94 MPa). Bond strength for 24 h storage was significantly higher (8.80 MPa) than for 90-day storage (7.40 MPa). It may be concluded that the thickness of resin cement influenced the bond strength of glass fiber posts. The customized posts presented higher bond strength. Storage in water for 90 days affected negatively the values of bond strength, especially for thick cement layers in the apical third.

Resumo O objetivo deste estudo foi avaliar a influência da espessura da linha de cimento na resistência de união de pinos de fibra de vidro após armazenamento em água destilada. Trinta dentes humanos hígidos unirradiculares tiveram os canais tratados endodonticamente. As raízes foram distribuídas em três grupos: THIN (linha de cimento fina): conduto preparado com broca 0,5 e cimentação de pino 0,5; THICK (linha de cimento espessa): conduto preparado com broca 1 e cimentação de pino 0,5; e CUSTOM (linha de cimento personalizada): conduto preparado com broca 1 e cimentação de pino personalizada (pino 0,5 personalizado com resina composta). Os pinos foram cimentados com cimento auto-adesivo. Após armazenamento das raízes em água destilada a 37 °C por 24 h e 90 dias, o teste de cisalhamento por extrusão push-out foi realizado. Os resultados foram analisados estatisticamente por ANOVA a três fatores e teste de Tukey (a=0,05). A resistência de união foi significativamente maior para CUSTOM (9,37 MPa), do que para THIN (7,85 MPa) e THICK (7,07 MPa), que foram semelhantes entre si. Considerando-se os terços radiculares, a resistência de união variou na sequência: apical (7,13 MPa) < médio (8,22 MPa) = coronal (8,94 MPa). A resistência de união após 24 h de armazenamento em água foi significativamente maior (8,80 MPa) do que para 90 dias (7,40 MPa). Pode-se concluir que houve influência da espessura da linha de cimento na resistência de união de pinos de fibra de vidro, sendo que o uso de pinos personalizados apresentou maiores valores de resistência de união. O armazenamento em água por 90 dias afetou negativamente os valores de resistência de união, especialmente no terço apical, no grupo com linha de cimento mais espessa.