Influence of different surface treatments on bond strength of a Self-Adhesive resin cement to CAD-CAM materials / Influencia de los diferentes tratamientos superficiales en la unión del cemento resinoso autoadhesivo a los materiales CAD-CAM

To evaluate the shear bond strength (SBS) of self-adhesive resin cement when used with two different computer-aided design (CAD)-computer-aided manufacturing (CAM) materials after various surface treatments. Nanoceramic resin Lava Ultimate (LU) and feldspathic ceramic Vita Mark II (VM) CAD-CAM block samples were prepared with 1.5-mm thickness, and a total of 90 samples were obtained (N=90), with five samples of each block. The samples were divided into the following five groups according to the surface treatments (n=9): group 1, untreated (control); group 2,5% hydrofluoric acid etching; group 3, Er: YAG laser irradiation; group 4, tribochemical silica coating (Cojet); and group 5, air-abrasion with Al2O3. After silane application, resin cement was applied on a transparent matrix (diameter, 3mm; height, 2mm) on the blocks. SBS was determined using a universal testing device at a crosshead speed of 1mm/min. Two-way analysis of variance (ANOVA) and Tukey's post hoc tests were used to analyze the SBS values. LU showed the highest SBS value in group 4. The average SBS values in groups 3 and were found to be lower than that in the control group (p<0.05). When VM was examined, while all surface treatments increased the SBS values significantly, the highest SBS value was observed in group 4 (p<0.05). This study revealed that all surface treatments used negatively affected the bond strength values of self-adhesive resin cement to LU, except for Cojet application. The SBS values of resin cement with VM increased in all surface treatment application groups.

Evaluar la resistencia de unión al corte (SBS) del cemento de resina autoadhesivo cuando se utiliza con dos materiales diferentes de diseño asistido por computadora (CAD) y fabricación asistida por computadora (CAM) después de varios tratamientos superficiales. Se prepararon muestras de bloques CAD-CAM de resina Lava Ultimate (LU) y cerámica feldespática Vita Mark II (VM) con un espesor de 1,5mm, y se obtuvieron un total de 90 muestras (N=90), con cinco muestras de cada bloque. Las muestras se dividieron en los siguientes cinco grupos según los tratamientos superficiales (n=9): grupo 1, sin tratar (control); grupo 2, grabado con ácido fluorhídrico al 5%; grupo 3, irradiación con láser Er: YAG; grupo 4, recubrimiento triboquímico de sílice (Cojet); y grupo 5, aire-abrasión con Al2O3. Después de la aplicación de silano, se aplicó cemento de resina sobre una matriz transparente (diámetro, 3mm; altura, 2mm) sobre los bloques. La SBS se determinó usando un dispositivo de prueba universal a una velocidad de cruceta de 1mm/min. Se utilizaron análisis de varianza bidireccional (ANOVA) y pruebas post hoc de Tukey para analizar los valores de SBS. LU mostró el valor más alto de SBS en el grupo 4. Los valores promedio de SBS en los grupos 3 y fueron más bajos que en el grupo de control (p<0,05). Cuando se examinó VM, mientras que todos los tratamientos superficiales aumentaron significativamente los valores de SBS, el valor más alto de SBS se observó en el grupo 4 (p<0,05). Este estudio reveló que todos los tratamientos de superficie utilizados afectaron negativamente los valores de resistencia de la unión del cemento de resina autoadhesivo a LU, a excepción de la aplicación Cojet. Los valores de SBS del cemento de resina con VM aumentaron en todos los grupos de aplicación de tratamiento de superficie.

Effect of novel pre-sintered zirconia surface treatment on shear bond strength between zirconia and veneering porcelain compared to conventional surface treatments: an in-vitro study / Efeito de um novo tratamento de superfície de zircônia pré-sinterizada na resistência ao cisalhamento entre zircônia e porcelana em comparação com os tratamentos de superfície convencionais: estudo in vitro

Objective: to evaluate the effect of novel zirconia surface treatment method on shear bond strength between zirconia and veneering porcelain compared to air abrasion and CoJet surface treatment methods. Material and Methods: twenty-one zirconia ceramic discs were fabricated with diameter of 7mm and 3mm thickness and divided according to surface treatment into three subgroups, control group I: Air Abrasion (n=7), group II: CoJet (n=7) and group III: Z-etch (n=7). Porcelain was built over the zirconia specimens with a customized mold and fired in a ceramic furnace. All specimens were thermocycled (20000 cycles) between 5°C ­ 55 °C with a dwell time of 30 seconds in distilled water and shear bond strength of veneering porcelain to each zirconia specimen was tested using a universal testing machine. Results: numerical data were explored for normality by checking the distribution of data and using tests of normality (Kolmogorov-Smirnov and Shapiro-Wilk tests). One-way ANOVA test was used to compare between the groups. There was a statistically significant difference between the three groups (P-value = 0.002, Effect size = 0.503). Pair-wise comparisons between groups revealed that Z-etch showed the statistically significantly highest mean shear bond strength. Conclusion: zirconia coating using z-etch is showing promising results in promoting higher bond strength than conventional surface treatment methods as air abrasion and silica coating (AU)

Objetivo: avaliar o efeito do novo método de tratamento de superfície de zircônia na resistência ao cisalhamento entre a zircônia e a porcelana de cobertura em comparação com os métodos de abrasão a ar e jateamento com CoJet. Material e Métodos: vinte e um discos de zircônia foram confeccionados com diâmetro de 7mm e espessura de 3mm e divididos de acordo com o tratamento de superfície em três subgrupos, grupo controle I: Abrasão a ar (n=7), grupo II: CoJet (n=7) e grupo III: Z-etch (n=7). A porcelana foi aplicada sobre os espécimes de zircônia com um molde personalizado e sinterizada em forno de cerâmica. Todos os espécimes foram termociclados (20.000 ciclos) entre 5°C - 55°C com um tempo de permanência de 30 segundos em água destilada e a resistência ao cisalhamento da porcelana de cobertura foi testada através de uma máquina de ensaio universal. Resultados: os dados numéricos foram avaliados quanto à normalidade, verificando a distribuição dos dados e utilizando testes de normalidade (testes de Kolmogorov-Smirnov e Shapiro-Wilk). O teste ANOVA de um fator foi utilizado para comparar os grupos. Houve uma diferença estatisticamente significativa entre os três grupos (P-valor = 0,002, tamanho do efeito = 0,503). As comparações pareadas entre os grupos revelaram que o Z-etch apresentou a resistência de união ao cisalhamento estatisticamente significativamente mais alta. Conclusão: o revestimento de zircônia utilizando Z-etch mostrou resultados promissores para o aumento da resistência de união em comparação aos métodos convencionais de tratamento de superfície, como abrasão a ar e revestimento de sílica (AU)

Influência da adição de partículas de vidro bioativas em adesivos resinosos, na cimentação de bráquetes ortodônticos / Influence of the addition of bioactive glass particles in resin adhesives in the cementation of orthodontic brackets

O objetivo deste estudo foi desenvolver e avaliar um adesivo resinoso modificado com a incorporação de partículas de vidro bioativas (SCHOTT Bioactive Glass) em diferentes concentrações. Foram avaliados a resistência ao cisalhamento (RU), o índice de remanescente dentário (IRA), o grau de conversão (GC) e a liberação de cálcio. Foram utilizados 50 incisivos bovinos que foram fixados, através de suas raízes, em um molde de PVC, com resina acrílica autopolimerizável. As amostras foram alocadas em 5 grupos (n=10): TXT - Adesivo Transbond XT (3M Unitek, Monrovia, CA, EUA) sem adição de partículas de vidro bioativas, TXT20, TXT30, TXT50 ­ Adesivo Transbond XT acrescido respectivamente de 20%, 30% e 50% de partículas de vidro bioativas e SH - Adesivo resinoso FL BOND ll (SHOFU Inc.) com biomaterial SPRG. As amostras receberam uma profilaxia com pedra pomes e condicionamento com ácido fosfórico à 37%. Em seguida foi aplicada uma fina camada do sistema adesivo indicado na face vestibular dos incisivos bovinos, em todos os grupos e fotopolimerizado por 20 segundos, utilizando-se um fotopolimerizador RADII-Cal (SDI, Victoria, Austrália). Depois foi aplicada uma pequena quantidade de pasta resinosa fotopolimerizável Transbond XT (3M Unitek, Monrovia, CA, EUA) sobre a superfície dos bráquetes autoligados (MORELLI, Sorocaba, São Paulo, Brasil) e estes foram devidamente colados na face vestibular, no centro da coroa clínica do incisivo bovino e fotopolimerizado por 20 segundos, em cada face. Posteriormente as amostras foram submetidas ao teste de resistência ao cisalhamento. O índice de remanescente adesivo foi avaliado em estereomicroscópio DISCOVERY V20 (ZEISS). Os adesivos resinosos foram submetidos ao teste de grau de conversão e liberação de cálcio. Os dados foram inicialmente submetidos ao teste de normalidade e depois submetidos ao teste de ANOVA um fator, seguido do teste de Tukey para análise de comparações múltiplas, com nível de significância de 0,05. De acordo com os resultados obtidos na resistência de união ao cisalhamento (MPa±Dp) a maior média foi observada no grupo TXT 19,50±1,40A, seguida do grupo TXT20 18,22±1,04AB, seguida do grupo SH 17,62±1,45B, seguida do grupo TXT30 14,48±1,46C e a menor média TXT50 14,13±1,02C. No grau de conversão a maior média foi observada no grupo TXT20 73,02±3,33A que foi estatisticamente semelhante ao grupo SH 68,50±1,09A, seguida do grupo TXT 60,28±1,06B e TXT30 58,84±4,06B e a menor média foi do grupo TXT50 40,67±1,21C.Para a liberação de cálcio a maior média foi TXT50 2,23±0,11D, seguida por TXT30 0,74±0,00C, TXT20 0,55±0,00B, SH 0,47±0,04B e TXT 0,14±0,00A. Concluiu-se que a incorporação de partículas de vidro bioativas influenciou na resistência de união ao cisalhamento, no grau de conversão e na liberação de cálcio (AU).

The objective of this study was to develop and evaluate a resin adhesive modified with the incorporation of bioactive glass particles (SCHOTT Bioactive Glass) in different concentrations. Shear bond strength (SBS), adhesive remnant index (ARI), degree of conversion (DC) and calcium release were evaluated. Fifty bovine incisors were used, which were fixed through their roots in a PVC mold with self-curing acrylic resin. The samples were allocated into 5 groups (n=10): TXT ­ Transbond XT Adhesive (3M Unitek, Monrovia, CA, USA) without addition of bioactive glass particles, TXT20, TXT30, TXT50 ­ Transbond XT Adhesive rescpectively increased by 20%, 30% and 50% bioactive glass particles and SH ­ FL BOND ll resin adhesive (SHOFU Inc.) with SPRG biomaterial. The samples received prophylaxis with pumice stoe and conditioning with 37% phosphoric acid. Then, a thin layer of the indicated adhesive system was applied to the buccal surface of the bovine incisors, in all groups, and light cured for 20 seconds, using a RADII-Call curing light (SDI, Victoria, Australia). Then, a small amount of Transbond XT light-curing resinous paste (3M Unitek, Monrovia, CA, USA) was applied on the surface of the self-ligating brackets (MORELLI, Sorocaba, São Paulo, Brazil) and these were duly bonded on the buccal surface, in the center of the clinical crown of the bovine incisor and light cured for 20 seconds, on each side. Subsequently, the samples were submitted to the shear bond test. The adhesive remnant index was evaluated using a DISCOVERY V20 stereomicroscope (ZEISS). The resin adhesives were submitted to the degree of conversion and calcium release test. The data were initially submitted to the normality test and then submitted to the one-way ANOVA test, followed by the Tukey test for analysis of multiple comparisons, with a significance level of 0.05. According to the results obtained in the shear bond strength (MPa±Dp), the highest average was observed in the TXT group 19.50±1.40A, followed by the TXT20 group 18.22±1.04AB, followed by the SH group 17.62±1.45B, followed by the TXT30 group 14.48±1.46C and the lowest mean TXT5014.13±1.02C. In the degree of conversion, the highest average was observed in the TXT20 73.02±3.33A group, wich was statiscally like the SH group 68.50±1.09A, followed by the TXT 60.28±1.06B and TXT30 group 58.84±4.06B and the lowest mean was for the TXT50 group 40.67±1.21C. For calcium release, the highest mean was TXT50 2.23±0.11D, followed by TXT30 0.74±0.00C, TXT20 0.55±0.00B, SH 0.47±0.04B and TXT 0.14±0.00A. It was concluded that the incorporation of bioactive glass particles influenced in the shear bond strength, in the degree of conversion and in the release of calcium (AU).

Influence of etching Mode and composite type on bond strength to biodentine using a ''No-Wait'' universal adhesive / Influencia del modo de grabado y del tipo de resina en la resistencia adhesiva al Biodentine utilizando un adhesivo universal tipo "no-wait"

Abstract: The purpose of this study was to compare the shear bond strength (SBS) of four resin-based composite materials to a silicate-based cement using a ''no-wait'' universal bond with self-etch (SE) and etch-and-rinse (ER) modes. Acrylic blocks (n=80, 2mm depth, 5mm diameter central hole) were prepared. The holes were filled with BiodentineTM (BD) and divided into 4 main groups (n=20) according to the composite resin type used: Group FZ250: FiltekTM Z250 Universal Restorative (microhybrid), Group SDR: SDR Plus U Bulk Fill Flowable (low-viscosity bulk-fill), Group FBP: FiltekTM Bulk Fill Posterior (high-viscosity bulk-fill), Group EF: EsFlow™ Universal Flowable Composite (nanohybrid). A 'no-wait' universal bond (Clearfil Universal Bond Quick) was used for bonding application. Then each group was divided into 2 subgroups according to the etching mode applied (ER and SE). SBSs were measured and stereomicroscope was used to identify the failure modes. Selected samples of fracture surfaces were imaged by SEM. Tukey's post-hoc and One-way ANOVA tests were used to analyze data. There were statistically significant differences among the composite groups (p 0.05). The SBS of BD to the resin composites depends on the composite type but application of the 'no-wait' universal bond in different etching modes is regardless of the SBS of BD to resin composites.

Resumen El objetivo de este estudio fue comparar la resistencia de adhesión al cizallamiento (SBS) de cuatro resinas con un cemento a base de silicato utilizando una adhesivo universal "no-wait" de autograbado (SE) y grabado y lavado (ER). Se prepararon bloques acrílicos (n=80, de 2mm de profundidad y un agujero central de 5mm de diámetro). Los agujeros se rellenaron con BiodentineTM (BD) y se dividieron en 4 grupos principales (n=20) según el tipo de resina compuesta utilizada: Grupo FZ250: FiltekTM Z250 Universal Restorative (microhíbrido), Grupo SDR: SDR Plus U Bulk Fill Flowable (bulk-fill de baja viscosidad), Grupo FBP: FiltekTM Bulk Fill Posterior (bulk-fill de alta viscosidad), Grupo EF: EsFlow™ Universal Flowable Composite (nanohíbrido). Para la aplicación de la adhesión se utilizó un adhesivo universal "no-wait" (Clearfil Universal Bond Quick). A continuación, cada grupo se dividió en 2 subgrupos según el modo de grabado aplicado (ER y SE). Se midieron los SBS y se utilizó el estereomicroscopio para identificar los modos de fallo. Las muestras seleccionadas de las superficies de fractura se analizaron mediante SEM. Se utilizaron las pruebas post-hoc de Tukey y ANOVA de una vía para analizar los datos. Hubo diferencias estadísticamente significativas entre los grupos de composites (p0,05). La SBS de la BD a los composites de resina depende del tipo de composite, pero la aplicación de la unión universal "no-wait" en los diferentes modos de grabado es independiente de la SBS de la BD a los composites de resina.

How does radiotherapy affect the adhesion of universal adhesive to enamel and dentin? A qualitative and quantitative analysis? / Efecto de la radioterapia a la adhesión del adhesivo universal al esmalte y dentina? Un análisis cualitativo y cuantitativo?

Abstract This study investigated the shear bond strength (SBS) of a universal adhesive to enamel/dentin; 1) that had undergone radiotherapy (RT) and 2) that were readily restored and had undergone RT. Enamel and dentin surfaces were obtained from 90 intact human molars. They were randomly divided into six groups according to the presence and timing of irradiation (RT0:no radiotherapy/control, RT1:RT before restoration, RT2:RT after restoration groups) and adhesive application modes (etch&rinse/ER, self-etch/SE)(n=15). A universal adhesive and resin composites were applied. The radiotherapy protocol was conducted with 60 Gy. The SBS test was subjected (1mm/min) and failure type analysis was performed. The resin-enamel/dentin interfaces were examined. Data were statistically analyzed. For enamel and dentin, the presence and timing of irradiation did not significantly influence the SBS values (p>0.05). For enamel, significantly higher SBS values were obtained using etch&rinse mode than self-etch mode (p<0.05). The predominant failure was mixed type. Loss of enamel prisms and obliterated irregular dentinal tubules were found for the radiotherapy-treated specimens. Resin tags were clearer in the irradiated enamel treated with ER than SE. Irradiation with different timings did not influence the bond strength to enamel and dentin, negatively. Irrespective of radiotherapy, the etch&rinse mode caused higher bond strength to enamel than self-etch mode.

Resumen Este estudio investigó la fuerza de unión al cizallamiento (SBS) de un adhesivo universal al esmalte/dentina en piezas que se habían sometido a radioterapia (RT). Se obtuvieron superficies de esmalte y dentina de 90 molares humanos intactos. Se dividieron aleatoriamente en seis grupos según la presencia y el momento de la irradiación (RT0: sin radioterapia/control, RT1: RT antes de la restauración, RT2: RT después de la restauración considerando los modos de aplicación del adhesivo (n=15). Se aplicó un adhesivo universal y resinas compuestas. El protocolo de radioterapia se realizó con 60 Gy. Se sometió a la prueba adhesiva (1mm/min) y se realizó análisis del tipo de falla. Se examinaron las interfases resina-esmalte/dentina. Los datos fueron analizados estadísticamente. Para el esmalte y la dentina, la presencia y el momento de la irradiación no influyeron significativamente en los valores adhesivos (p>0,05). Para el esmalte, se obtuvieron valores adhesivos significativamente más altos utilizando el modo de grabado y enjuague que el modo de autograbado (p<0,05). La falla predominante fue de tipo mixto. Se encontró pérdida de prismas de esmalte y túbulos dentinarios irregulares obliterados en las muestras tratadas con radioterapia. La irradiación con diferentes tiempos no influyó negativamente en la fuerza de unión al esmalte ni a la dentina. Independientemente de la radioterapia, el modo de grabado ácido y enjuague provocó una mayor fuerza de adhesión al esmalte que el modo de autograbado.

Effect of three different conditioning agents on cavosurface microleakage and bond strength of glass ionomer restorations – An in vitro study

Aim: This study aimed to investigate the conditioning effects of phosphoric acid/5.25% sodium hypochlorite (NaOCl) mixture, 2% chlorhexidine (CHX) digluconate, and 10% polyacrylic acid on cavosurface microleakage and bond strength of glass ionomer (GI) restorations. Materials and Methods: Out of 68 extracted premolars, 34 teeth were selected for microleakage and 34 for bond strength evaluation. The samples were divided into the following four groups. Group 1: pretreatment with 50/50 volume% mixture of 5.25% NaOCl solution and 37% phosphoric acid (H3PO4), Group 2:pretreatment with 2% CHX digluconate, Group 3: pretreatment with 10% polyacrylic acid (positive control), and Group 4: no pretreatment (negative control). All the samples were then restored with glass ionomer cement (GIC). Microleakage was evaluated using a stereomicroscope and rhodamine-B dye penetration test. For bond strength, flat dentin surface was exposed and pretreated as mentioned previously and restored with GIC and was evaluated using universal testing machine. Results: Among all the four groups, Group 1 showed least microleakage and highest bond strength when compared with other groups. Whereas the Group 4 samples which were not pretreated with any of the conditioning agent showed the least shear bond strength with greatest cavosurface microleakage when compared to the groups which were pretreated with the conditioning agents. Conclusions: A combination of 50/50 volume % mixture of 37% H3PO4 and 5.25% NaOCl can be a good choice for surface pretreatment of GI restorations.

Evaluation of Self-Adhering Flowable Composites on Repeated Bracket Bonding Process: An In Vitro Study

ABSTRACT@#Duration of orthodontic treatment becomes major concern. The present study compared shear bond strength (SBS) and adhesive remnant index (ARI) values of different adhesive systems with different application methods on rebonding process of retrieved orthodontic brackets. Eighty premolar teeth were equally divided into five groups. Transbond XT (TXT) which belongs to total-etch system was used in Group 1 as the control group. Nova Compo-SF (NC) and Vertise Flow (VF) (Kerr Dental, Italy) which are self-adhering flowable composites were used in Group 2 (NC+etch) and Group 3 (VF+etch) respectively with additional etching before application. Group 4 (NC) and Group 5 (VF) were used by following instructions of each brand. The brackets were debonded with a bracket removing plier and rebonded with the same procedures after sandblasting of the bracket and surface cleaning of the enamel. SBS and ARI were measured for each sample. Comparison between all groups was performed by Kruskal-Wallis test and chisquare test. The highest SBS was observed in NC+etch (median = 11.44, mean = 13.49±9.42), followed by NC (median = 10.17, mean = 11.35±6.55), TXT (median = 6.36, mean = 8.06±6.33), VF+etch (median = 5.68, mean = 6.75±4.58), and VF (median = 2.62, mean = 2.92±2.57), respectively. ARI 1 was observed in 81.3% of TXT whereas 62.5% of NC+etch. ARI 1, 2, and 3 were equally distributed in VF+etch group (31.3%). ARI 5 was observed in 37.5% of NC and 62.5% of VF. Analyses referred to statistically significant differences between five groups regarding both SBS and ARI (p < 0.001). As NC showed the highest SBS on rebonding process, it can be a promising alternative to TXT which is the gold standard.

Influence of diode laser and warm air drying on the shear bond strength of Lithium di-silicate to Dentin. An in-vitro study / Influência do laser de diodo e da secagem com ar quente na resistência ao cisalhamento do Di-silicato de Lítio a dentina. Um estudo in-vitro

Objective: The current study aimed to evaluate the effect of diode laser irradiation (980 nm) and warm air drying (50°C) on shear bond strength between Lithium di-silicate (IPS e.max; Ivoclar) and human dentin using both (Etch & Rinse) adhesive, Adper™ Single Bond 2 (3M ESPE) and (Self-etch) adhesive, Single Bond UniversalTM(3M ESPE) before adhesive polymerization. Material and Methods: 54 sound lower molars were sectioned to obtain flat dentinal surfaces. Specimens were divided into 2 equal groups (n=27): Group 1 (ER) and Group 2 (SE) according to bonding approach. Each subgroup was subdivided according to dentin surface treatment into 3 equal subgroups (n=9): Control (Co), Diode laser irradiation (L) and Warm air drying (W). All specimens were adhesively cemented to IPS e.max® CAD discs using RelyX™ Ultimate Clicker™(3M ESPE) resin cement. Samples were then subjected to pre-loading in a thermodynamic manner. All samples were tested for shear bond strength using computer-controlled material testing machine. Data analysis was performed using two-way (ANOVA) (p< 0.05) followed by pair-wise Tukey's post-hoc tests. Results: In (SE) group, the subgroup (W) had the highest shear bond strength values followed by (Co) subgroup and the least was (L) subgroup with statistically significant difference. As for (ER) group, the subgroup (W) had the highest shear bond strength values followed by (Co) subgroup and the least was (L) subgroup with no statistically significant difference. Conclusion: Warm air drying for (SE) bonding approach increased shear bond strength of Lithium di-silicate to human dentin and can be introduced as a new effective protocol.(AU)

Objetivo: o objetivo do estudo atual é avaliar o efeito da radiação do laser de diodo (980nm) e secagem de ar quente (50°C) na resistência ao cisalhamento entre dissilicati de Lítio (IPS e.max; Ivoclar) e a dentina humana usando ambos modelos de adesivos (condicionamento total) Adper™ Single Bond e (auto-condicionante) Single Bond Universal™ (3M ESPE), Single Bond UniversalTM (3M ESPE) antes da fotopolimerização. Material e Métodos: 54 segundos molares inferiores foram selecionados para obter superfícies dentinárias planas. Os espécimes foram divididos em 2 grupos iguais (n=27): grupo 1 (ER) e grupo 2 (SE) de acordo com protocolo de adesividade. Cada grupo foi subdividido de acordo com o tratamento de superfície dentro de 3 subgrupos iguais (n=9): Controle (co), irradiação com laser de diodo (L) e secagem com ar quente (W). Todos os espécimes foram adesivamente cimentados a discos de IPS emax CAD usando RelyX Ultimate Clicker (3M ESPE) cimento resinoso. As amostras foram então submetidas a pré-carregamento de forma termodinâmica. Todas as amostras foram testadas para resistência a cisalhamento usando máquina de teste de materiais controlados por computador. A análise de dados foi realizada usando ANOVA dois fatores (p<0.05) seguindo por testes de Tukey pareado como test post-hoc. Resultados: No grupo (SE), o subgrupo (W) apresentou maiores valores de resistência ao cisalhamento seguindo o subgrupo (Co) é o menor foi o subgrupo (L) com diferença estatisticamente significativa. Já para o grupo (Er), o subgrupo (W) apresentou os maiores valores de resistência ao cisalhamento seguido do grupo (Co) e o menor foi o subgrupo (L) sem diferença estatisticamente significante. Conclusão: a secagem com ar quente para a abordagem de adesividade (Se) aumentou a resistência ao cisalhamento do dissilicato de lítio à dentina humana e poderia ser introduzido como um novo e eficaz protocolo(AU)

In vitro study of chlorhexidine acetate compound mesoporous silica orthodontic modified binder resin / 口腔疾病防治

Objective@#The antibacterial properties and bonding strength of 3M orthodontic adhesive resin modified by chlorhexidine acetate (CHA) composite mesoporous silica were investigated.@*Methods@# CHA with different mass fractions was encapsulated in mesoporous silica nanoparticles (MSNs) (denoted CHA@MSNs). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the samples. The 3M Z350XT flow resin was divided into 4 groups: group A: 3M+CHA@MSNs (0%); group B: 3M+CHA@MSNs (3%); group C: 3M+CHA@MSNs (5%); and group D: 3M+CHA@MSNs (6.4%), with mass scores of 0%, 3%, 5%, and 6.4%, respectively. The shear strength of the modified adhesive was tested by a universal electronic material testing machine, the adhesive residue was observed by a 10 × magnifying glass, and the adhesive Remnant index (ARI) was calculated. The four groups of modified adhesives were cultured with Streptococcus mutans. The OD540 value of the bacterial solution was measured by a spectrophotometer, and the amount of plaque attachment was observed by scanning electron microscopy to evaluate the antibacterial performance of the adhesives.@*Results@#Infrared spectroscopic analysis of CHA@MSNs showed that CHA was successfully loaded onto MSNs. Under scanning electron microscopy, it could be seen that, after Cha was combined with MSNs, the structure of MSNs changed, as the boundary was fuzzy and aggregated into a layered structure. A comparison of shear strength revealed a statistically significant difference between the groups containing CHA@MSNs and the groups without CHA@MSNs (P<0.05). The value of the shear strength in group D decreased the most, while there was no statistically significant difference between group B and group C (P > 0.05). There was no statistical significance across all groups (P > 0.05), suggesting that the addition of CHA@MSNs had little effect on the bracket shedding. The OD540 value of bacterial fluid indicated that the difference among groups A, B and C was statistically significant (P < 0.05), and the antibacterial effect of group C was the best; there was no statistically significant difference between group C and group D (P > 0.05).@*Conclusions@#Therefore, adding 5% CHA@MSN antibacterial agent significantly improved the antibacterial effect and did not affect the bond strength.

Effects of different pretreatment agents on primary tooth dentin bonding durability / 口腔疾病防治

Objective@#To explore the effects of different pretreatment agents on primary tooth dentin bonding durability.@*Methods @#Forty-two retained primary molars were selected, 24 of which were cut along the mesial and distal directions; thus, 48 samples were obtained for shear bond strength tests, and the other 18 teeth were used for nanoleakage tests. According to different pretreatments, both experimental samples were divided randomly into three groups (Group A: distilled water pretreatment group; Group B: 2% chlorhexidine pretreatment group; Group C: 10 mg/mL resveratrol pretreatment group). The test specimens were prepared, the shear bond strength was tested, and interfacial nanoleakage evaluation and scanning electron microscope observation were performed to evaluate the effects of different pretreatment agents on the bonding interface immediately and after aging for one hour with 10% sodium hypochlorite aqueous solution.@*Results @#The immediate shear bond strength results showed that there was no significant difference among the three test groups. After aging, the shear bond strength of Group C was significantly higher than that of Group A and Group B (P<0.05). After aging, the shear bond strength of Group A was significantly lower than the immediate shear bond strength (P<0.05), whereas there was no significant difference in shear bond strength before and after aging in Group B and Group C (P>0.05). For Group C, there was no significant difference in interfacial nanoleakage before and after aging. In addition, among the three groups, Group C had the lowest interfacial nanoleakage (P<0.05).@*Conclusion@# Both chlorhexidine and resveratrol pretreatment can improve the adhesion durability of deciduous dentin, but the effects of resveratrol are better than those of chlorhexidine.

Evaluation of enamel roughness after the removal of brackets bonded with different materials: In vivo study

Abstract The aims of this in vivo study were to evaluate the effect of bonding with resin-modified glass ionomer cement (RMGIC) and to assess enamel surface roughness before and after the removal of brackets bonded with composite or RMGIC from the maxillary central incisors. Fifteen orthodontic patients were selected for the study. For each patient, the teeth were rinsed and dried, and brackets were bonded with composite (Transbond XT) and RMGIC (Vitremer Core Buildup/Restorative). At the conclusion of orthodontic treatment, their brackets were removed. Dental replicas were made of epoxy resin in initial conditions (before bonded) and after polishing with an aluminum oxide disc system. Adhesive remnant index (ARI) and surface roughness was measured on the dental replicas and data were evaluated statistically by Mann-Whitney and paired t-test, respectively. No bracket debonding occurred during patients' treatment periods. It was verified that the ARI values of the two maxillary central incisors were similar (p = 0.665). For both bonding materials, the ARI value of 3 was predominant. After polishing, surface roughness was similar in the composite and RMGIC groups (0.245 μm and 0.248 μm, respectively; p = 0.07). In both groups, enamel surface roughness values were significantly lower after polishing compared with the initial condition (p < 0.001). RMGIC promoted efficiency in cementing brackets without fail during treatment; the choice of composite or RMGIC materials was not a factor that influenced the roughness of the enamel surface, however, polishing led to smoother surfaces than those found at the beginning of the treatment.

Resumo Os objetivos deste estudo in vivo foram avaliar o efeito da colagem com cimento de ionômero de vidro modificado por resina (CIVMR) e a rugosidade da superfície do esmalte antes e após a remoção dos braquetes colados com compósito ou CIVMR em incisivos centrais superiores. Quinze pacientes ortodônticos foram selecionados para o estudo. Para cada paciente, os dentes foram lavados e secos, e os braquetes colados com compósito (Transbond XT) e CIVMR (Vitremer Core Buildup / Restorative). Ao término do tratamento ortodôntico, os braquetes foram removidos. As réplicas dentais foram confeccionadas em resina epóxica nas condições iniciais (antes da colagem) e após o polimento com sistema de discos de óxido de alumínio. O índice de remanescente adesivo (IRA) e a rugosidade da superfície foram mensurados nas réplicas dentais e os dados foram avaliados estatisticamente por Mann-Whitney e teste t pareado, respectivamente. Não ocorreu descolagem de braquetes durante os períodos de tratamento dos pacientes. Verificou-se que os valores do IRA dos dois incisivos centrais superiores foram semelhantes (p = 0,665). Para ambos os materiais de colagem, o valor de IRA predominante foi 3. Após o polimento, a rugosidade da superfície do esmalte foi semelhante nos grupos compósito (0,245 μm) e CIVMR (0,248 μm) (p = 0,07). Em ambos os grupos, os valores de rugosidade da superfície do esmalte foram significativamente menores após o polimento em comparação com a condição inicial (p <0,001). CIVMR promoveu eficiência na colagem de braquetes sem falhas durante o tratamento; a escolha dos materiais compósito ou CIVMR não foi um fator que influenciou na rugosidade da superfície do esmalte, porém, o polimento levou a superfícies mais lisas do que as encontradas no início do tratamento.

Bonding performance of self-etch adhesives to enamel bleached with different peroxide concentrations

Abstract The aim of this study was to evaluate the micro-shear bond strength (µSBS) of one and two steps self-etch adhesive systems after enamel bleaching with photo-activated bleaching systems of different hydrogen peroxide (HP) concentration. Occlusal enamel of forty intact human molars were flattened and assigned into four groups. GI Unbleached, GII, GIII, and GIV were bleached with Pyrenees (3.5% HP), GC TiON (20% HP), and Hi-Lite (35% HP) respectively. Enamel treatment with one and two steps self-etch adhesives (Clearfil S3 Bond- S3, and Clearfil SE Bond-SE) then micro-tubes were fixed on enamel and filled with AP-X composite (n=5). Bond was tested with the universal testing machine. Data were analyzed using two-way ANOVA and Tukey's tests at 5 % level of significance. The µSBS was significantly different between adhesives (F=154.46; p<0.05) and bleaching systems (F=77.33; p<0.05) with significant interaction. Specimens bonded with S3 shows a significantly lower μSBS than those bonded with SE (p<0.05) in all groups. For both adhesives the bleached groups demonstrate lower µSBS than unbleached except specimens bleached with Pyrenees and bonded with SE (p>0.05). A significant difference was observed between groups of the bleaching systems (p<0.05). Different peroxide concentrations photo-activated bleaching systems adversely affect μSBS of one and two steps self-etch adhesives. Low concentration system (Pyrenees) does not influence the bond strength of two steps adhesive.

Resumo O objetivo deste estudo foi avaliar a resistência ao cisalhamento (µSBS) de sistemas auto-adesivos de um e dois passos após clareamento do esmalte com sistemas de clareamento foto-ativados de diferentes concentrações de peróxido de hidrogênio (HP). O esmalte oclusal de quarenta molares humanos intactos foi aplainado e atribuído em quatro grupos. GI Unbleached, GII, GIII, e GIV foram branqueados com Pyrenees (3,5% HP), GC TiON (20% HP), e Hi-Lite (35% HP) respectivamente. Tratamento de esmalte com adesivos de um e dois passos auto-adesivos (Clearfil S3 Bond- S3, e Clearfil SE Bond-SE), depois os microtubos foram fixados no esmalte e preenchidos com composto AP-X (n=5). A resistência ao cisalhamento foi testada com a máquina universal de testes. Os dados foram analisados usando os testes de ANOVA e Tukey de duas vias a um nível de 5% de significância. O µSBS foi significativamente diferente entre adesivos (F=154,46; p<0,05) e sistemas de clareadores (F=77,33; p<0,05) com interação significativa. Os espécimes colados com S3 mostram um μSBS significativamente inferior aos colados com SE (p<0,05) em todos os grupos. Para ambos os adesivos, os grupos clareados demonstram µSBS inferiores aos não clareados exceto os espécimes clareados com Pyrenees e colados com SE (p>0,05). Foi observada uma diferença significativa entre os grupos dos sistemas de clareamento (p<0,05). Diferentes concentrações de peróxidos foto-ativados nos sistemas de clareamento afetam negativamente μSBS dos adesivos de uma e duas etapas de auto-colagem. O sistema de baixa concentração (Pyrenees) não influenciou a resistência ao cisalhamento do adesivo de duas etapas.

Bond Strength Evaluation of Bulk- fill Composites to Dentin Under Different Surface Treatments / Evaluación de la resistencia adhesiva de las resinas bulk-fill a la dentina con diferentes tratamientos de superficie

ABSTRACT: Purpose: The aim of this study is to compare the shear bond strength of three high-viscosity bulk-fill composite resins applied as single layers of 4mm thickness and of one microhybrid composite resin applied incrementally with a thickness of 2mm on dentin surfaces prepared with different surface preparation methods. Materials and Methods: A total of 132 caries-free human molars whose dentines had been exposed were used. Three groups, each containing 44 teeth, were formed. The acid group was etched with 32% phosphoric acid; laser group was etched with Er, Cr; YSGG laser and the control group was prepared with silicon carbid paper. Following the application of bonding agent, composite resin materials were applied on teeth using teflon moulds of 4x4mm. The samples were then subjected to shear bond strength tests. Two-way variance analysis and Tukey HSD multiple comparison test were applied on collected data. Results: There was a significant difference between surface treatment methods used regarding shear bond strength (P0.05). Conclusions: Laser etching of the dentin tissues is not as effective as acid etching. Bulk-fill composites had similar effects compared with conventional composite resins with regard to bonding strength. More in vitro studies supported with clinical data are required to investigate the performance of bulk-fill composites and laser.

RESUMEN: Propósito: El objetivo de este estudio es comparar la resistencia adhesiva al cizallamiento de tres resinas compuestas de relleno de alta viscosidad aplicadas como capas individuales de 4 mm de espesor y de una resina compuesta microhíbrida aplicada de forma incremental con un espesor de 2mm en superficies de dentina preparadas con diferentes métodos de preparación de la superficie. Materiales y métodos: Se utilizaron un total de 132 molares humanos sin caries cuyas dentinas habían sido expuestas. Se formaron tres grupos, cada uno con 44 dientes. El grupo ácido se grabó con ácido fosfórico al 32%; el grupo láser se grabó con Er, Cr; el láser YSGG y el grupo de control se preparó con papel de carburo de silicio. Después de la aplicación del agente adhesivo, se aplicaron materiales de resina compuesta en los dientes utilizando moldes de teflón de 4x4mm. A continuación, las muestras se sometieron a pruebas de resistencia adhesiva al cizallamiento. Se aplicó el análisis de varianza bidireccional y la prueba de comparación múltiple Tukey HSD a los datos recogidos. Resultados: Hubo una diferencia significativa entre los métodos de tratamiento de superficie utilizados en cuanto a la resistencia adhesiva al cizallamiento (P0,05). Conclusiones: El grabado láser de los tejidos de la dentina no es tan eficaz como el grabado al ácido. Las resinas de relleno bulk-fill tuvieron efectos similares en comparación con las resinas compuestas convencionales en lo que respecta a la rsistencia adhesiva. Se necesitan más estudios in vitro apoyados con datos clínicos para investigar el rendimiento de los composites de relleno y el láser.

Análisis comparativo in vitro de la resistencia adhesiva al cizallamiento de brackets metálicos adheridos a superficies dentarias tratadas con diferentes agentes blanqueadores / Comparative in vitro analysis of the adhesive resistance to the shear bond strength of metal brackets adhered to dental surfaces treated with different bleaching agents

RESUMEN: Objetivo: Evaluar y comparar el efecto de tres agentes blanqueadores en la resistencia adhesiva al cizallamiento de brackets metálicos. Método: Se cementaron 76 brackets en premolares humanos extraídos por indicación de ortodoncia. Se establecieron 4 grupos: (0) control, (1) esmalte tratado con Peróxido de Carbamida al 16%, (2) Peróxido de Hidrógeno al 35% y (3) tiras de blanqueamiento con Peróxido de Hidrógeno al 10%. Los brackets fueron cementados con Transbond XT (3M Unitek, EE.UU.). Se realizaron 5.000 ciclos de termociclado, luego se evaluó la resistencia adhesiva mediante una máquina Bisco y la cantidad de material adhesivo remanente según el índice adhesivo remanente (ARI). El análisis estadístico incluyó pruebas de Shapiro- Wilk, Kruskal -Wallis y Mann-Whitney. Resultados: Los grupos 0, 1, 2, 3 obtuvieron fuerzas de resistencia de 12.64, 11.06, 6.4 y 9.34 Mpa respectivamente con diferencia estadística entre los grupos (p <0.05). El ARI fue significativamente diferente en algunos grupos (p <0.05), indicando fallas adhesivas para el grupo 2 (p <0.05), cohesivas para el grupo control y de ambos tipos para los grupos 1 y 3. Conclusiones: El peróxido de hidrógeno al 35% reduce la resistencia adhesiva al cizallamiento en brackets metálicos sometidos a termociclado 24 horas luego del blanqueamiento.

ABSTRACT: Aim: To evaluate and compare the effect of three bleaching agents on the shear bond strength of metallic brackets. Method: Brackets were cemented on 76 human premolars extracted for orthodontic reasons. 4 groups were evaluated: (0) Control, (1) enamel treated with Carbamide Peroxide 16%, (2) Hydrogen Peroxide 35% and (3) Hydrogen Peroxide 10% "Whitening strips". All brackets were cemented using Transbond XT adhesive system (3M, Unitek, USA). All samples were thermocycled (5.000 cycles). Shear bond strength was evaluated with a Bisco machine and the amount of adhesive material at the base of the brackets and enamel surface was assessed using the adhesive remnant index (ARI). The statistical analysis included Shapiro-Wilk, Kruskal-Wallis and Mann-Whitney U tests. Results: The results of shear bond strength for groups 0, 1, 2, and 3 were 12.64, 11.06, 6.4 and 9.34 MPa respectively, with statistically significant differences between groups (p <0.05). ARI index was significantly different in some groups (p <0.05), indicating cohesive failure for control, adhesive failure for group 2 (p <0.05), adhesive and cohesive failure for groups 1 and 3. Conclusions: The 35% hydrogen peroxide office bleaching agent reduces adhesion values in the metal brackets thermocycled 24 hours after bleaching.

CO2 laser irradiation for debonding ceramic orthodontic brackets

Abstract This study evaluated shear bond strength (SBS), adhesive remnant index (ARI) and fracture mode of chemically and mechanically retained ceramic brackets bonded with different composite resins and irradiated with CO2 laser. The null hypothesis was that ceramic brackets bonded with different composite resins and irradiated with CO2 laser would have similar SBS values. Ninety human premolars were divided into four experimental groups according to the combination of type of composite resin (Transbond XT and Z 250) and type of ceramic bracket (Fascination and Mystique), and two control groups (n=15). In the four experimental groups, the brackets were irradiated with CO2 laser at 10 W for 3 seconds before SBS testing. Enamel surface ARI was calculated after debonding under electron microscopy scanning. ANOVA and the Mann-Whitney test were used for statistical analysis. The laser groups had lower SBS values than the non-irradiated groups (control) (p<0.05). The mechanically retained brackets (Mystique) had the higher (p<0.05) and Z250 had the lower SBS values after CO2 laser irradiation. The groups bonded with Z250 had the highest ARI. Adhesive fractures were the most prevalent. The null hypothesis was rejected. CO2 laser decreased SBS efficiently and facilitated debonding of mechanically and chemically retained ceramic brackets.

Resumo O objetivo do estudo foi avaliar a resistência de união ao cisalhamento da colagem (RCC), o índice de remanescente de adesivo (IRA) e o modo de fratura de bráquetes cerâmicos com retenção química e mecânica colados com diferentes compositos e irradiados com laser de CO2. A hipótese nula testada foi que bráquetes colados com diferentes compósitos e irradiados com laser de CO2 apresentam valores semelhantes de RCC. Noventa pré-molares humanos foram divididos em 6 grupos (n=15): 2 controles e 4 experimentais que se diferenciaram pelo tipo de bráquete ceramic (Fascination and Mystique) e pelo compósito de fixação (Transbond XT e Z 250). Nos quatro grupos experimentais, os bráquetes foram irradiados com laser de CO2 com 10W por 3 segundos anteriormente ao teste de RCC. O IRA das superficies de esmalte foram avaliados após a descolagem e submetidos a análise em microscopia electrônica de varredura (MEV). Para análise estatística foram utilizados ANOVA e o teste de mann-Whitney. Os grupos laser mostraram valores de RCC menores que os grupos não irradiados (controles) (p<0.05). Os bráquetes com retenção mecânica (Mystique) mostraram alta RCC (p<0.05) e o compósito Z 250 obteve os mais baixos valores de RCC após irradiação com laser. Os grupos colados com o compósito Z 250 apresentaram os mais altos escores do IRA. O modo de fratura mais prevalente foi a adesiva. A hipótese nula foi rejeitada. O laser de CO2 foi eficaz para diminuir os valores de RCC e facilitou a descolagem dos bráquetes cerâmicos de retenção química e mecânica

Influence of topical fluoride on shear bond strength of orthodontic brackets and enamel white spot lesions formation / Influência do flúor tópico na resistência ao cisalhamento de braquetes ortodônticos e na formação de lesões de manchas brancas no esmalte

Introduction Fluoride is considered a key element in the remineralization process of tooth enamel. Objective To evaluate the influence of a topical solution of sodium fluoride (NaF) on the shear bond strength of orthodontic brackets and white spot lesions formation. Material and method Sixty bovine teeth were divided into three groups (n=20). Group 1 (Control): shear bond strength; Group 2: shear bond strength after pH cycling; Group 3: shear bond strength after pH cycling and treatment with 0.04% NaF solution. Groups 2 and 3 underwent pH cycling with demineralizing (6hs) and remineralizing (17hs) solutions at pH of 4.3 and 7.0 respectively for 15 days. The specimens were submitted to the shear bond strength and the Adhesive Remnant Index was verified (ARI). The specimens of each group (n=3) were qualitatively analyzed by means of Scanning Electron Microscopy (SEM). Kruskal-Wallis test assessed the shear bond strength and Fisher's exact test evaluated ARI, with significance level of 5%. Result There was no significant difference among the three groups in shear bond strength (p=0.2679). Significant difference was found in ARI (p=0.0199). The frequency of ARI 1 was 55% in group 1, 90% in group 2, and 80% in group 3. SEM showed difference between the enamel and bonding. Group 2 showed structural change of the enamel surface, adjacent to the bond area; and group 3 showed enamel with characteristics similar to those of group 1. Conclusion It was concluded that there was no NaF influence on the bracket shear bond strength and even in low concentrations it prevented the development of areas of demineralization of white spot lesions.

Introdução O flúor é considerado um elemento chave no processo de remineralização do esmalte dentário. Objetivo Este estudo teve como objetivo avaliar a influência da solução tópica de fluoreto de sódio (NaF) na resistência ao cisalhamento da colagem de barquetes ortodônticos durante a formação de lesões de manchas brancas. Material e método Sessenta dentes bovinos foram divididos em três grupos (n=20). Grupo 1 (Controle) - Cisalhamento imediato; Grupo 2 - Cisalhamento após ciclagem de pH; Grupo 3 - Cisalhamento após ciclagem de pH e tratamento com solução de 0,4% de NaF (Ortho Gard, Colgate-Palmolive®). Os Grupos 2 e 3 sofreram ciclagem de pH com soluções de desmineralização e remineralização em pH de 4,3 e 7,0 respectivamente, com ciclos de desmineralização (6 horas) e remineralização (17 horas), durante 15 dias. Os corpos de prova foram submetidos ao teste de resistência de união ao cisalhamento e remanescente adesivo (IRA). Espécimes de cada grupo (n=3) foram analisados qualitativamente por microscopia eletrônica de varredura (MEV). O teste de Kruskal-Wallis foi utilizado para avaliar a resistência ao cisalhamento e o teste exato de Fisher para avaliação do IRA, adotando nível de significância de 5%. Resultado Os resultados não encontraram diferença significativa entre os três grupos quanto à força de cisalhamento (p=0,2679). Diferença significativa foi encontrada no IRA (p = 0,0199). A frequência de IRA 1 foi de 55% no grupo 1, 90% no grupo 2 e 80% no grupo 3. A análise em MEV mostrou diferença entre o esmalte e a área de colagem submetida ao cisalhamento. Grupo 2 apresentou alteração estrutural na superfície do esmalte adjacente à área de colagem, e o Grupo 3 apresentou esmalte com característica semelhante ao do Grupo 1 na área que foi submetida à ciclagem de pH e NaF. Conclusão Concluiu-se que não houve influência do flúor na resistência ao cisalhamento de braquetes. O uso de soluções fluoretadas, ainda que em baixa concentração, preveniu o aparecimento de áreas desmineralizadas e lesões de manchas brancas.

The effect of surface treatment and thermocycling on the shear bond strength of orthodontic brackets to the Y-TZP zirconia ceramics: A systematic review

ABSTRACT Introduction: Various surface pre-treatment methods have been adapted to optimize the bonding between the zirconia ceramics and the orthodontic brackets. Objective: This review is aimed at systematically analyzing the relevant data available in the literature, to find out the most effective and durable bonding protocol. Methods: Database search was conducted in PubMed, Scopus, and ScienceDirect, during September 2020. The review was conducted according to the PRISMA guidelines. Results: Based on the inclusion criteria, 19 articles were selected for qualitative analysis. Meta-analysis could not be performed due to the heterogeneity of the methodology among the studies. Most of the studies scored medium risk of bias. Compared to the untreated surface, surface pretreatments like sandblasting and lasers were advantageous. Primers and universal adhesive were mostly used as an adjunct to the mechanical pretreatment of the zirconia surface. In most studies, thermocycling seemed to lower the shear bond strength (SBS) of the orthodontic brackets. Conclusion: Based on this qualitative review, surface pretreatments with lasers and sandblasting can be suggested to optimize the bracket bond strength. To clarify this finding, meta-analysis is anticipated. Hence, high heterogeneity of the included studies demands standardization of the methodology.

RESUMO Introdução: Diferentes métodos de pré-tratamento da superfície foram adaptados para otimizar a colagem entre os braquetes ortodônticos e as cerâmicas de zircônia. Objetivo: A presente revisão teve como objetivo analisar, de forma sistemática, os dados relevantes na literatura, para buscar o protocolo de colagem mais efetivo e duradouro. Métodos: As buscas foram feitas em setembro de 2020, nas seguintes bases de dados: PubMed, Scopus e ScienceDirect. A revisão foi feita de acordo com as diretrizes do PRISMA. Resultados: Com base nos critérios de inclusão, 19 artigos foram selecionados para análise qualitativa. A metanálise não pôde ser feita, devido à heterogeneidade na metodologia dos estudos incluídos. A maior parte dos estudos apresentou risco de viés moderado. Comparadas às superfícies não tratadas, as superfícies com pré-tratamento usando jateamento ou laser apresentaram vantagem. Primers e adesivos universais foram mais usados como adjuntos ao pré-tratamento mecânico da superfície de zircônia. Na maioria dos estudos, a termociclagem parece ter reduzido a resistência ao cisalhamento dos braquetes ortodônticos. Conclusões: Com base nessa revisão qualitativa, os pré-tratamentos de superfície com laser e jateamento podem ser sugeridos para otimizar a resistência ao cisalhamento dos braquetes. Para esclarecer esse achado, uma metanálise é necessária. Para isso, faz-se necessária a padronização da metodologia, para lidar com a alta heterogeneidade dos estudos incluídos.

The Effect of Different Surface Treatment Protocols on the Shear Bond Strength to Repressed Lithium Disilicate Glass Ceramics / Efeito de diferentes protocolos de tratamento de superfície na resistência ao cisalhamento de vitrocerâmica de dissilicato de lítio reprensado

Objective: The present study aimed to evaluate the effect of repressing and different surface treatment protocols on the shear bond strength of lithium disilicate glass-ceramics. Material and Methods: A total of 52 lithium disilicate glass-ceramic discs (IPS emax Press, Ivoclar Vivadent) were fabricated using the heat-press technique. The discs were divided into two groups; group (P): discs fabricated from new e.max ingots (n=26), group (R): discs fabricated from reused e.max buttons (n=26). Each group was subdivided into subgroup (E): discs were etched with hydrofluoric acid (9.5%) (n=13), subgroup (S): discs were air-abraded with 110 µm alumina particles. All specimens were subjected to X-ray Diffraction analysis, Scanning Electron Microscope, Energy Dispersive X-Ray, Thermo-Cycling, and Shear Bond Strength Testing. Results: Repressed Etched subgroup (RE) recorded the statistically highest shear bond strength value, followed by the Pressed Etched subgroup (PE), while the statistically lowest shear bond strength value was recorded for the Pressed Air-Abraded subgroup (PS) and Repressed Air-Abraded subgroup (RS). Conclusion: Repressing the leftover buttons for the construction of new lithium disilicate glass-ceramic restorations has no adverse effect on the bond strength of the resin cement to the ceramic. Hydrofluoric acid surface treatment improves the shear bond strength and durability of resin cement bond to both pressed and repressed lithium disilicate glass-ceramic. Air-abrasion cannot be considered as a reliable surface treatment when bonding to lithium disilicate glass-ceramics. (AU)

Objetivo: O presente estudo teve como objetivo avaliar o efeito da reprensagem e de diferentes protocolos de tratamento de superfície na resistência ao cisalhamento de vitrocerâmica de dissilicato de lítio. Materiais e Métodos: Um total de 52 discos de vitrocerâmica de dissilicato de lítio (IPS emax Press, Ivoclar Vivadent) foram fabricadas usando a técnica de prensagem quente. Os discos foram divididos em dois grupos: grupo (P): discos fabricados a partir de novo lingotes de e-max (n=26), grupo (R): discos fabricados a partir de botões de emax reutilizados (n=26). Cada grupo foi subdividido em subgrupo (E): discos condicionados com ácido fluorídrico (9,5%) (n=13), subgrupo (S) discos foram abrasivos com partícula 110 µm de alumínio. Todos os espécimes foram submetidos a analise de difração de raio-x, microscópio eletrônico de varredura, raio-x de energia dispersiva, termociclagem e teste de resistência de cisalhamento. Resultados: O subgrupo Reprensado-condicionado (RE) registrou o valor estatisticamente mais alta em relação a resistência ao cisalhamento, seguido pelo subgrupo Prensado-condicionado (PE), enquanto o valor estatisticamente mais baixo de resistência ao cisalhamento foi o subgrupo Prensado-Jateado (OS) e o subgrupo Reprensado-Jateado (RS). Conclusão: A reprensagem dos botões restantes para a construção de novas restaurações vitrocarâmicas de dissilicato de lítio não apresentou efeitos adversos na resistência de unicãp do cimento resinoso à cerâmica. O tratamento de superfície com ácido fluorídrico melhora a resistência ao cisalhamento e a durabilidade do cimento resinoso para vitrocerâmica de dissilicato de lítio prensada e reprimida. A abrasão por ar não pode ser considerada um tratamento de superfície confiável quanto a colagem da vitrocerâmica de dissilicato de lítio (AU)

Potencial mecânico da associação de diferentes tratamentos com a deposição de filmes por vapor químico melhorado por plasma na superfície da zircônia / Mechanical potential of the association of different treatments with the deposition of films by plasma enhanced chemical vapor deposition on the zirconia surface

Caracterizar a superfície de zircônia (Y-TZP) submetida a diferentes tratamentos de superfície (com e sem associações de plasma) e avaliar a resistência ao cisalhamento (RC) com a cerâmica de cobertura (CC) após diferentes métodos de envelhecimento. 301 espécimes de 3Y-TZP (IPS e.max ZirCAD) foram fabricados e distribuídos em 7 grupos (n = 43): Grupo C (controle): sem tratamento; Grupo Al: jateamento com partícula de Al2O3 de 27 µm; Grupo L: liner; Grupo P: plasma; Grupo Al+L: jateamento + liner; Grupo Al+P: jateamento + plasma; Grupo P+L: plasma + liner. A superfície de Y-TZP foi caracterizada por Micrsocopia Eletrônica de Varredura (MEV), Espectroscopia por Energia Dispersiva (EED), Microscopia por Força Atômica (MFA), perfilometria de superfície e energia livre de superfície (ELS). Difração de Raio-x (DRX) foi usada para verificar a estrutura do cristal de Y-TZP após cada tratamento de superfície realizado. A RC entre Y-TZP e a cerâmica de cobertura foi verificada após três protocolos de envelhecimento: inicial, após envelhecimento hidrotérmico (autoclave por 5h) ou termociclagem (30.000 banhos - 5-55°C). ANOVA de um (profilometria e ELS) e de dois fatores (RC) e o teste de Tukey HSD foram usados como análise estatística. Para os grupos de plasma, uma cobertura homogênea e total da superfície foi observada em MEV e MFA, com formação globular. Picos de Si foram encontrados para os grupos Al, L, Al+L e P+L. A rugosidade foi menor para os grupos C, P e Al+P. Para ELS, os maiores valores foram encontrados quando o liner foi aplicado (> 74,59 nm/Nm). O maior conteúdo monoclínico foi observado para Al+L (6,96%) e Al+P (5,86%). Para o período inicial, o grupo Al e P+L apresentaram os menores valores de RC ( 0,331). Após o envelhecimento hidrotérmico, os grupos L, P e P+L apresentaram os maiores valores de RC (> 8,25 MPa; P< 0,001). Após a termociclagem, os grupos P, L, Al+L e Al+P apresentaram os maiores valores de RC (> 6,35 MPa; P < 0,001). Foram constatadas alterações na topografia da Y-TZP e na RC com a CC, de acordo com os tratamentos realizados. O tratamento com plasma melhorou a resistência ao cisalhamento e não causou transformação de fase(AU)

To characterize the zirconia (Y-TZP) surface submitted to different surface treatments (with and without plasma associations) and to evaluate the shear bond strength (SBS) with the veneering ceramic (VC) after different aging methods. 301 3Y-TZP specimens (IPS e.max ZirCAD) were fabricated and distributed into 7 groups (n=43): Group C (control): no treatment; Group Al: airborne abrasion with 27 µm Al2O3 particle; Group L: liner; Group P: plasma; Group Al+L: airborne abrasion + liner; Group Al+P: airborne abrasion + plasma; Group P + L: plasma + liner. The Y-TZP surface was characterized by SEM, EDS, AFM, surface profilometry, and surface-free energy (SFE). XRD was used to verify the crystal structure after each surface treatment performed. SBS between Y-TZP and the veneering ceramic was verified after three aging protocols: initial, after hydrothermal aging (autoclave for 5h), or thermal fatigue (30,000 baths - 5-55°C). One- (profilometry and SFE) and two-way ANOVA (SBS), and Tukey's HSD test were used as statistical analysis. For the plasma groups, a homogeneous and a full surface coverage was observed on SEM and AFM, with globular formation. Peaks of Si were found for Al, L, Al+L, and P+L groups. Roughness was lower for groups C, P, and Al+P. For SFE, the highest values were found when the liner was applied (>74.59 nm/Nm). The highest monoclinic content was observed for Al+L (6.96%) and Al+P (5.86%). For the initial period, group Al and P+L presented the lowest SBS values (< 5.85 MPa; P> 0.331). After hydrothermal aging, groups L, P, and P+L presented the highest SBS values (> 8.25 MPa; P< 0.001). After thermal fatigue, P, L, Al+L, and Al+P groups had the highest SBS values (> 6.35 MPa; P< 0.001). Changes in Y-TZP topography and the SBS with the VC were observed, according to treatments performed. Plasma treatment improved SBS and did not cause phase transformation(AU)

Effects of concentrated sulfuric acid etching durations on the shear bond strength between polyether-ketone-ketone and dentin / 口腔疾病防治

Objective@# To study the effects of different concentrated sulfuric acid etching durations on the shear bond strength between polyether-ketone-ketone (PEKK) and dentin, providing a scientific basis for the clinical bonding procedures of PEKK prosthesis.@*Methods@# Forty-four PEKK specimens were prepared and randomly divided into four groups: group A was the control group, which was only polished with abrasive papers, group B, group C and group D were experimental groups, which were etched by 98% concentrated sulfuric acid for 5 s, 30 s and 60 s, respectively. In addition, one sample was randomly selected from each group, and the profile was prepared by a slow cutting machine. The surface morphology of the profile was observed under SEM. After the four groups of specimens and dentin were bonded by resin, they were soaked in distilled water at 37 ℃ for 24 h. After the shear bonding strengths were measured, the fracture interfaces of the specimens were examined by the scanning electron microscopy and stereomicroscopy, and failure models of bonding were analyzed. @*Results@#After acid etching treatments, the cross-sectional images in group B presented uniform spongy shapes, while the cross-sectional images in group C and group D showed destructive pore structures. The shear bond strengths of group B (16.84 ± 1.84) MPa, group C (12.33 ± 1.22) MPa and group D (6.44 ± 1.18) MPa were higher than that of group A (3.99 ± 1.06) MPa (P < 0.05). The highest shear bond strength was observed in group B (16.84 ± 1.84) MPa. @*Conclusion @#The surface treatment of 98% sulfuric acid etching for 5 s manifested the best bond strength between PEKK and dentin.