Influence of viscosity and fiber reinforcement of resin composite on fracture strength and failure mode of restored molars.

OBJECTIVE: To evaluate the fracture behavior of human molars with extensive MOD restorations using short-fiber-reinforced resin composite of varying viscosities. MATERIALS AND METHODS: Human molars were randomly divided into seven groups (n = 12): intact teeth (control); restoration using conventional high-viscosity resin composite without (Filtek Z350XT, 3M) or with fibers (everX Posterior, GC); conventional low-viscosity resin composite without (Filtek Supreme Flowable, 3M) or with fibers (everX Flow Dentin Shade, GC); bulk-fill low-viscosity resin composite (Filtek Bulk Fill Flow, 3M) or with fibers (everX Flow Bulk Shade, GC). Restorations were performed on extensive MOD preparations, following the manufacturers' recommendations for each material. Specimens underwent fracture strength testing (N) and fracture pattern (%) categorized as repairable, possibly repairable, or non-repairable. Results were analyzed using a generalized linear model (N) and Fisher's exact test (%), with α = 0.05. RESULTS: Restorations performed with high-viscosity materials showed fracture strength values similar to the control and higher than those of restorations using low-viscosity resin composites (p < 0.0001), except for the bulk-fill low-viscosity resin composite with fibers (p > 0.05). Teeth restored using low-viscosity resin composite with fibers showed a higher % of repairable and possibly repairable fractures than the control (p = 0.0091). CONCLUSIONS: The viscosity of materials mediated the fracture strength, with restorations using high-viscosity resin composites promoting values similar to the intact tooth; however, the presence of fibers influenced the fracture pattern. CLINICAL SIGNIFICANCE: Teeth with MOD cavities restored with high-viscosity resin composites showed similar fracture strength to intact teeth. Fiber-reinforced low-viscosity resin composite for the base of restoration resulted in a more repairable/possibly repairable fracture pattern.

Color Stability of Single-Shade Resin Composites in Direct Restorations: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The objective was to compare the color match and color stability behavior of single- and multi-shade resin-based composites (RBCs) used for direct restorations. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized clinical trials evaluating the shade performance of single-shade RBCs in direct restorations were included. A search of the scientific literature was performed in five databases (April 2024). The meta-analysis was performed using RevMan 5.4, calculating the risk difference (RD) and 95% confidence interval (CI) of the dichotomous outcome using a random effects model. Bias was assessed using the RoB 2.0 tool, and certainty of evidence was assessed using the GRADEpro tool. Four studies were selected, with 263 restorations analyzed. The results showed comparable performance between single-shade RBCs and multi-shade RBCs in terms of color match and color stability over 12 months. Three studies had a low risk of bias with all expected results, and one study had some concerns. The certainty of evidence for color stability was considered low for all follow-up periods due to the small number of events and sample size. According to the United States Public Health Service Evaluation (USPHS) and the World Dental Federation (FDI), there is comparable clinical color performance between single-shade and multi-shade RBCs over 12 months.

Abordagem estética e conservadora para fechamento de múltiplos diastemas: relato de caso / Aesthetic and conservative approach to multiple diastema closure: case report / Enfoque estético y conservador para el cierre de múltiples diastemas: relato de caso

Introdução:Na odontologia moderna, a estética vem ocupando um espaço cada vez mais expressivo, e o desejo por dentes mais brancos, a insatisfação com o alinhamento dos dentes e com a anatomia dentária, têm sido os motivos mais relevantes de procura dos pacientes nos consultórios odontológicos.Objetivo:O presente artigo tem como objetivo descrever, através de relato de caso clínico, uma abordagem terapêutica estética e conservadora para fechamento de múltiplos diastemas anterossuperiores com a utilização de facetas de resina composta.Relato de caso:Paciente do sexo masculino, 21 anos de idade, procurou atendimento queixando-se de insatisfação estética pelos diastemas apresentados. Por meio de um planejamento digital das facetas em resina, com mockup e modelo impresso em 3D, as restaurações foram feitas respeitando anatomia, forma, opacidade e cores dos dentes naturais do paciente. O resultado dos procedimentos adotados foi satisfatório, demonstrando que a técnica empregada foi eficaz, sendo capaz de devolver um sorriso estético e biológico ao paciente. A odontologia contemporânea tem ofertado cada vez mais materiais com capacidade de devolver estética e função em dentes de forma minimamente invasivas, além de passar total confiabilidade em tratamentos a longo prazo, agradando o paciente desde a apresentação digital do planejamento traçado pelo cirurgião dentista com previsibilidade dos resultados, até o momento final do tratamento.Conclusões:O recontorno estético com resina composta representa uma opção funcional e de baixo custo para o tratamento de pacientes que apresentam diastemas múltiplos, principalmente em pacientes jovens pela preservação daestrutura dentária e possibilidade de reparo, sendo considerado um procedimento reversível, rápido e de baixo custo (AU).

Introduction:Aesthetics have been occupying an increasingly significant role in modern dentistry, and the desire for whiter teeth, dissatisfaction with tooth alignment, and dental anatomy concerns have been the most relevant reasons for patients seeking dental care. Objective:This article aims to describe an aesthetic and conservative therapeutic approach for closing multiple anterior upper diastemas using composite resin veneers in a clinical case report. Case report:A 21-year-old male patient sought treatment, expressing dissatisfaction with the diastemas he had. The restorations were performed using digital planning of the resin veneers with a mockup and a 3D-printed model, while respecting the patient's natural tooth anatomy, shape, opacity, and colors. The results of the adopted procedures were satisfactory, demonstrating effectiveness of the employed technique in restoring an aesthetic and biologically harmonious smile to the patient. Contemporary dentistry has been offering increasingly more materials capable of providing aesthetics and function to teeth through minimally invasive approaches. This not only ensures long-term treatment reliability, but also pleases the patient with a digital presentation of the treatment plan outlined by the dentist, predicting the results up to the final stages of the treatment. Conclusions:Aesthetic contouring using composite resin presents a functional and cost-effective option for treating patients with multiple diastemas, especially among young patients due to its preservation of dental structure, repair potential, and being considered a reversible, fast, and low-cost procedure (AU).

Introducción: En la odontología moderna, la estética viene ocupando un espacio cada vez más destacado, y las ganas de tener dientes más blancos, la insatisfacción con el alineamiento de los dientes, y la anatomía dental son las razonesmás relevantes por las cuales los pacientes acuden a las consultas odontológicas. Objetivo:El presente artículo tiene como objetivo describir, a través de un relato de caso clínico, un abordaje terapéutico estético y conservador para el cierre de múltiples diastemas anterosuperiores mediante el uso de carillas de resina compuesta. Informe de caso:Paciente del sexo masculino, 21 años de edad, buscó atendimiento quejándose de insatisfacción estética debido a los diastemas presentados. A través de una planificación digital de las carillas en resina, con un mockup y un modelo impreso en 3D, las restauraciones fueron ejecutadas, respetándose la anatomía, forma, opacidad y colores de los dientes naturales del paciente. El resultado de los procedimientos adoptados fue satisfactorio y demostró que la técnica utilizada fue eficaz, siendo capaz de restituir una sonrisa estética y funcional al paciente. La odontología contemporánea viene ofreciendo cada vez más materiales con la capacidad de devolver estética y función a los dientes de maneras mínimamente invasivas, además de brindar total confiabilidad en tratamientos a largo plazo, satisfaciendo al paciente desde la presentación digital del plan trazado por el cirujano dentista con la previsibilidad de los resultados, hasta el momento final del tratamiento. Conclusiones:El recontorneado estético con resina compuesta representa una opción funcional y de bajo costo para el tratamiento de pacientes con múltiples diastemas, especialmente en pacientes jóvenes, debido a la preservación de la estructura dental y la posibilidad de reparación. Se considera, de este modo, que se trata de un procedimiento reversible, rápido y económico (AU).

[Surface roughness of two composite resins after immersion in soda drinks: in vitro study]. / Rugosidad superficial de dos resinas compuestas después de la inmersión en bebidas gaseosas: estudio in vitro.

Objective: Compare the surface roughness of two composite resins after immersion in carbonated beverages. Materials and methods: 160 resin discs (6 x 2 mm) were divided into 8 groups (n=20 per group) according to type of resin (Filtek™ Z350 XT® and Palfique LX5®) and type of immersion in beverages (distilled water, Coca Cola®, Inca Kola® and Kola Escocesa®. The immersions were carried out under a structured cycle: 4 immersions a day for 5 days, intermediate storage in distilled water and overnight incubation for 8 h at 37°C. The measurements with the roughness meter were evaluated in three times: baseline, 7 and 14 days. The three-way Anova test was used at P<0.05. Results: Roughness showed differences only for the individual factors of time (P<0.000) and resin (P=0.000), and for the interaction time*drink (P=0.000) and resin*drink (P=0.003). Roughness was higher with Filtek Z350 XT® immersed with Inca Kola® (0.85 ± 0.37) than 14 days compared to other times (P=0.035) and with Palfique LX5 immersed in Coca Cola® at 7 days (1.61 ± 0.42) and in Inca Kola® at 14 days (1.66 ± 0.56) compared to distilled water (P<0,05). Conclusion: Surface roughness was affected by the type of resin, the type of soft drink and the immersion time. The roughness was greater with the Palfique LX5® nanohybrid resin, the Inca Kola® drink and after 14 days of immersion.

Influence of different opacities and layering technique of nanotechnology composite resins regarding the wavelength and fluorescence intensity: in vitro study / Influencia de diferentes opacidades y la técnica de estratificación de resinas compuestas de nanotecnología en la longitud de onda e intensidad de fluorescencia: estudio in vitro

Objective: To evaluate the influence of opacity and the layering technique on the fluorescence of different composite resins. Materials and Methods: Two opacities (enamel and dentin) and the layering technique (enamel + dentin) of the composite resins: Filtek® Z350 and Palfique LX5 were evaluated in vitro. Composite resin discs were fabricated using a preformed matrix of 10 mm diameter and 0.5 mm thick for the single opacity groups and 10 mm thick for the layering technique groups, using 2 layers of 0.5 mm thickness of each opacity (n = 5). Specimens were analyzed using the Raman spectroscopy method. Data were analyzed using the Kruskall-wallis and Mann-Whitney U tests. Results: When evaluating the intensity of fluorescence, no statistically significant difference was found when comparing the layering technique and enamel opacity (p2> 0.05) and an increase in the dentin opacity value for both brands of composite resin. Regarding wavelength, no statistically significant difference was found when comparing the layering technique with enamel opacity and dentin opacity for both Filtek® Z350 and Palfique LX5® composite resins (p2 > 0.05). Conclusions: The fluorescence intensity of the layering technique is similar to enamel opacity for both composite resins. Likewise, the wavelength of the layering technique is similar to the enamel opacity and dentin opacity for both brands.

Objetive: Evaluar la influencia de la opacidad y de la técnica de estratificación en la fluorescencia de diferentes resinas compuestas. Materiales y Métodos: Se evaluó in vitro 2 opacidades (Esmalte y Dentina) y la técnica de estratificación (Esmalte + Dentina) de las resinas compuestas: Filtek® Z350 y Palfique LX5. Se fabricaron discos de resina compuesta, utilizando una matriz preformada de 10 mm de diámetro y 0,5 mm de grosor para los grupos de opacidad única y 10 mm de grosor para los grupos de técnica estratificada, utilizando 2 capas de 0,5 mm de cada opacidad (n = 5). Los especímenes se analizaron mediante el método de Espectroscopía Raman. Los datos se analizaron utilizando la prueba de Kruskall-wallis y Prueba U de Mann Whitney. Resultado: Al evaluar la intensidad de fluorescencia no se encontró diferencia estadísticamente significativa entre los pares: Técnica estratificada versus Opacidad Esmalte para ambas marcas de resina compuesta Filtek® Z350 y para Palfique LX5® (p2 > 0,05). Para longitud de onda no se encontró diferencia estadísticamente significativa entre los pares: Técnica estratificada versus Opacidad Esmalte y Técnica estratificada VS Opacidad Dentina para ambas resinas compuesta Filtek® Z350 y Palfique LX5® (p2> 0,05). Conclusión: La intensidad de fluorescencia de la técnica estratificada es similar a la opacidad Esmalte para ambas resinas compuestas. De igual manera la longitud de onda de la técnica estratificada es similar a la opacidad Esmalte y opacidad Dentina para ambas marcas.

Longevity of composite restorations in posterior teeth placed by dental students: a 12-year retrospective study.

OBJECTIVES: To evaluate the longevity of resin composite restorations placed in posterior teeth by dental students, using data from electronic records from 2008 to 2019. MATERIALS AND METHODS: Demographic (gender and age) and clinical variables (dental group, position in dental arch, and the number of restored surfaces) were evaluated. The 5-year follow-up was assessed according to the day the restoration was placed. Kaplan-Meier curves were generated to calculate the annual failure rate. Data were analyzed by Chi-Square, Kruskal-Wallis, and Mann-Whitney tests (α = 0.05). RESULTS: In total, 3.883 records relative to return periodicity were analyzed. The final sample consisted of 900 restorations from 479 patients. The majority were females, aged between 31 and 60. In total, 256 failures were reported (success rate = 78%), showing an annual failure rate of 2.05%. The main reasons for failures were restoration replacement (55.5%), endodontics (21.9%), prosthetics (14.5%) and extraction (8.2%). There was a higher risk of failure in restorations involving three or more surfaces (p = 0.000) and in patients over 60 years (p < 0.001). In females (p = 0.030), molars (p = 0.044), and maxillary teeth (p = 0.038) failed in a shorter time. CONCLUSIONS: Resin composite restorations placed in permanent posterior teeth by dental students had high survival rates. The main reason for failure was the replacement of restorations. The age group and the number of restored surfaces significantly affected the success of the restorations. CLINICAL RELEVANCE: The electronic health records over 12 years showed that 78% of the resin restorations in posterior teeth placed by dental students were successful for a minimum of five years.

Influencia del termociclado sobre la estabilidad del color de dos resinas compuestas / Influence of thermocycling on the color stability of two composite resins

Objetivo: Cuando las resinas compuestas son expuestas a procesos de envejecimiento naturales en boca, como es el ciclaje térmico, pueden sufrir un deterioro en sus propiedades ópticas. El objetivo de este estudio fue evaluar la influencia del envejecimiento térmico sobre la estabilidad del color de dos resinas compuestas. Materiales y métodos: Se confeccionaron 120 pas- tillas de resinas compuestas, divididas en dos grupos: uno de resina Spectra Smart (n=60) y otro de resina Filtex Z350 XT (n=60). Estas muestras fueron sometidas a distintos regíme- nes de ciclaje térmico de 0, 10.000, 20.000 y 30.000 ciclos con temperaturas de entre 5 ºC +/- 2 ºC y 55 ºC +/- 2 °C. Los parámetros de color CIE L*a*b* de cada muestra se mi- dieron con un espectrofotómetro antes y después del proceso de envejecimiento. Las diferencias de color se calcularon me- diante la fórmula CIELAB (ΔE). Los datos fueron analizados estadísticamente usando la prueba no paramétrica de Kruskal Wallis y de U-Mann Whitney. Resultados: Los distintos regímenes de termociclado produjeron cambios de color estadísticamente significativos en ambos materiales. El material que tuvo menor estabilidad cromática fue Spectra Smart aunque sin diferencias estadísti- camente significativas. Conclusión: El envejecimiento térmico simulado a tres años afecta la estabilidad de color de las muestras, tanto de las resinas Spectra Smart, como de Filtex Z350 XT, sin alcanzar los valores que clínicamente determinarían la necesidad del reemplazo de las restauraciones (AU)

Aim: When composite resins are exposed to natural ag- ing processes in the mouth, such as the thermal cycling, they may suffer a deterioration in their optical properties. The aim of this study was to evaluate the influence of thermal aging on the color stability of two composite resins. Materials and methods: 120 composite resins tablets were made, divided into two groups: one of Spectra Smart res- in (n=60) and another of Filtex Z350 XT resin (n=60). These were subjected to different thermal cycle regimes of 0, 10,000, 20,000 and 30,000 cycles with temperature between 5 °C +/- 2 °C and 60 °C +/- 2 °C. The CIE L*a*b* color parameters of each sample were measured with a spectrophotometer before and after the aging process. Color differences were calculat- ed using the CIELAB formula (ΔE). The data were statisti- cally analyzed using the non-parametric Kruskal Wallis and U-Mann Whitney tests. Results: The different thermocycling regimes produce statistically significant color changes in both materials. The material that had the least chromatic stability was Spectra Smart, although without statistically significant differences. Conclusion: Simulated 3 year thermal aging affects the color stability of the samples, both Spectra Smart resins and Filtex Z350 XT, without reaching the values that would clini- cally determine the need to replace the restorations (AU)

Adhesion and sealing of different universal adhesive systems associated with bulk-fill resins after using endodontic irrigation solutions: An in vitro study.

This study aimed to evaluate the interface of universal adhesive (UA) with bulk-fill resin (BF) and dentin, after endodontic irrigation. The pulp chamber of 96 molars was irrigated with chlorhexidine 2% (CHX) or sodium hypochlorite 5.25% (NaOCl) and restored according to three restorative protocols. Microtensile bond strength (µTBS) and nanoleakage tests were performed after 24 h of thermocycling. Kruskal Wallis, Mann-Whitney and Wilcoxon were performed (p < 0.05). Comparing restorative systems, a difference was found only when irrigated with CHX after 24 h. CHX provided higher µTBS than NaOCl after 24 h for two restorative protocols; after thermocycling, NaOCl provided the greatest µTBS than CHX for one group. Decreased µTBS was observed for all restorative systems when CHX was used after thermocycling. NaOCl demonstrated the highest nanoleakage. The composition of UA influenced the immediate adhesion and sealing to BF when CHX was used; ageing has a deteriorating effect on adhesion and sealing for all restorative systems.

Bonding performance and interfacial adaptation of modern bulk-fill restorative composites after aging in artificial saliva: an in vitro study.

OBJECTIVES: This study aimed at comparing the microtensile bond strength (MTBS) and interfacial adaptation of a modern self-curing and a light-curing restorative bulk-fill composite to a conventional composite applied with the layering technique. METHODS: Forty-eight occlusal cavities were divided in three main groups (16/group) based on tested materials: (i) STELA, bulk-fill self-curing restorative (STELA, SDI Ltd.); (ii) 3 M-BULK, bulk-fill composite (Filtek One Bulk-Fill, 3 M Oral Care); and (iii) 3 M-CTR, a conventional composite (Filtek Supreme XTE, 3 M Oral Care). These were used in combination with their adhesives in self-etch (SE) or etch-and-rinse (ER) mode. Specimens stored in artificial saliva (24 h or 12 months) were evaluated for MTBS and fractography. The interfacial analysis was performed through confocal microscopy. ANOVA and Fisher's LSD post hoc tests were performed with a level of significance of 5%. RESULTS: All the tested materials applied in ER mode presented (24 h) greater bond strength than in SE mode. Although all materials showed a significant drop in the bond strength after prolonged storage, STELA showed the highest bonding performance and interfaces with few gaps. 3 M-BULK had the lowest bond strength and an interface with several voids and gaps. CONCLUSIONS: All materials were affected by interface degradation and bonding reduction over prolonged aging. However, their use in combination with adhesives applied in ER mode may offer greater immediate bonding performance. CLINICAL RELEVANCE: The use of restorative light-curing bulk-fill composites may generate gaps at the bonding interface and voids. STELA may represent a suitable alternative to avoid such issues.

Comparación de la microdureza de resina compuesta con técnica índex convencional y modificada con cubeta impresa en dos tiempos de fotopolimerizado / Comparison of the microhardness of composite resin with conventional and modified index techniques with printed cuvette in two light-curing times / Comparação da microdureza da resina composta com a técnica de índice convencional e modificada com moldeira impressa em dois tempos de fotopolimerização

RESUMEN Objetivo : Comparar la microdureza de la resina compuesta con técnica índex convencional y modificada con cubeta impresa en dos fotopolimerizaciones. Materiales y métodos : Se contó con seis grupos de estudio de acuerdo a la técnica y a la cantidad de fotopolimerizaciones: técnica directa con una fotopolimerización (D1F), directa con dos fotopolimerizaciones (D2F), índex convencional con una fotopolimerización (IC1F), índex convencional con dos fotopolimerizaciones (IC2F), índex modificada con una fotopolimerización (IM1F), índex modificada con dos fotopolimerizaciones (IM2F). Se utilizaron quince muestras por cada grupo. Las muestras tuvieron dimensiones de 2 mm de altura por 5 mm de diámetro. Se realizó la fotopolimerización siguiendo las indicaciones del grupo al que corresponde, para luego someter a la prueba de dureza de Vickers a tres indentaciones por cada cara con carga de 200 g por 15 segundos. Se realizaron dos registros de microdureza, una superficial y otra a 2 mm. Se recolectaron los datos en el instrumento confeccionado y fueron procesados mediante SPSS v. 26. Resultados : Existe una diferencia significativa entre los grupos de microdureza superficial de primera fotopolimerización (p < 0,001); y también existe diferencia significativa entre los grupos de microdureza a 2 mm de primera fotopolimerización (p < 0,001). Asimismo, no existen diferencias significativas entre los grupos de microdureza superficial de segunda fotopolimerización (p = 0,519) ni en los grupos de microdureza a 2 mm de segunda fotopolimerización (p = 0,279). Conclusiones: No existen diferencias significativas en la microdureza superficial y a 2 mm de profundidad con técnica índex convencional y modificada en cubeta impresa en dos fotopolimerizaciones.

ABSTRACT Objective : To compare the microhardness of composite resin with conventional and modified index techniques with a printed tray in two light cures. Materials and methods : There were six study groups according to the technique and the number of photopolymerizations: direct technique with one photopolymerization (D1F), direct with two photopolymerizations (D2F), conventional index with one photopolymerization (IC1F), conventional index with two photopolymerizations (IC2F), modified index with one photopolymerization (IM1F), modified index with two photopolymerizations (IM2F). Fifteen samples were used for each group. The samples had dimensions of 2 mm in height by 5 mm in diameter. The photopolymerization was performed following the indications of the group to which it corresponds and then subjected to the Vickers hardness test with three indentations on each side with a load of 200 g for 15 seconds. Two microhardness recordings were made, one superficial and the other at 2 mm. Results : There is a significant difference between the first light-curing surface microhardness groups (p < 0.001), and there is also a significant difference between the first light-curing 2 mm microhardness groups (p < 0.001). Likewise, there are no significant differences between the second light-curing surface microhardness groups (p = 0.519) or the second light-curing 2 mm microhardness groups (p = 0.279). Conclusions : There are no significant differences in surface microhardness and microhardness at 2 mm depth with conventional and modified index techniques in printed trays in two photopolymerizations.

RESUMO Objetivo : Comparar a microdureza da resina composta com a técnica de índice convencional e modificada com moldeira impressa em duas fotopolimerizações. Materiais e métodos : Foram constituídos seis grupos de estudo de acordo com a técnica e o número de ciclos de fotopolimerização: técnica direta com um ciclo de fotopolimerização (D1F), direta com dois ciclos de fotopolimerização (D2F), índice convencional com um ciclo de fotopolimerização (IC1F), índice convencional com dois ciclos de fotopolimerização (IC2F), índice modificado com um ciclo de fotopolimerização (IM1F), índice modificado com dois ciclos de fotopolimerização (IM2F). Foram utilizadas quinze amostras para cada grupo. Os espécimes tinham 2 mm de altura por 5 mm de diâmetro. A fotopolimerização foi efetuada de acordo com as indicações do grupo a que corresponde, e depois submetida ao teste de dureza Vickers com três indentações de cada lado com uma carga de 200 g durante 15 segundos. Foram efetuados dois registos de microdureza, um superficial e outro a 2 mm. Os dados foram recolhidos no instrumento e processados utilizando o SPSS v. 26. Resultados : Há uma diferença significativa entre os primeiros grupos de microdureza superficial fotopolimerizável (p < 0,001); e há também uma diferença significativa entre os primeiros grupos de microdureza de 2 mm fotopolimerizável (p < 0,001). Da mesma forma, não há diferença significativa entre os grupos de microdureza da superfície do segundo fotopolimerizador (p = 0,519) e nos grupos de microdureza de 2 mm do segundo fotopolimerizador (p = 0,279). Conclusões : Não existem diferenças significativas na microdureza da superfície e na microdureza a 2 mm de profundidade com a técnica de índice convencional e modificada em duas fotopolimerizações.

Influence of light exposure techniques on in vitro pulp temperature rise during bulk fill composite Class I restorations.

This in vitro study assessed peak temperature and temperature increase (ΔT) within the pulp chamber during different extended photoactivation techniques (EPT-applying similar radiant exposure values) to resin-based composites (RBCs) placed in a Class I cavity preparation in an extracted human lower third molar. A T-type thermocouple was placed in the pulp chamber and connected to a temperature analysis device (Thermes, Physitemp). The tooth was attached to an assembly simulating the in vivo environment (controlled baseline pulp chamber temperature and fluid flow). The real-time pulp chamber temperature was evaluated throughout the photoactivation (Bluephase N, Ivoclar Vivadent) of two bulk-fill RBCs: Tetric N Ceram Bulk Fill (TBF; shade: IVA; Ivoclar Vivadent); Surefill SDR flow + (SDR, shade: Universal; Dentsply Sirona), which were exposed to different curing techniques: 40 s-occlusal surface; 20 s-occlusal + 10 s-buccal + 10 s-lingual surfaces; 10 s-buccal + 10 s + lingual + 20 s-occlusal surfaces. Each EPT delivered 42.4 J/cm2. Vickers hardness (VHN) was measured on the removed, sectioned RBC restorations at the top and bottom middle areas after curing. ΔT and VHN data were analyzed using 2-way ANOVA followed by Bonferroni post-hoc test (α = 0.05). Peak temperature data were analyzed using one-way ANOVA and Dunnett's post-hoc test (α = 0.05). SDR showed higher ΔT values than TBF (p = 0.008) in some EPTs. Neither technique resulted in ΔT values greater than 5.5 °C. Both composites had acceptable bottom/top hardness ratios (greater than 80%), regardless of the photoactivation technique. The evaluated EPTs may be considered safe as a low-temperature increase was noticed within the pulp chamber.

Assessment of bulk-fill of resins microhardness longitudinal

Aim: This study aimed to assess the polymerization effectiveness of bulk-fill composite resins in longitudinal microhardness. Methods: Blocks of bulk-fill composite resin with thicknesses of 6 mm were analyzed with Vickers microhardness. The resin blocks were divided into two groups (n=6): resin AURA and OPUS. The microhardness test was performed before (base and top) and after (longitudinal microhardness) sectioning the blocks at distances of 2 mm, 4 mm, and 6 mm from the top of the block. The mean microhardness values were tabulated and subjected to ANOVA followed by Tukey's test (p<0.05). Results: The OPUS bulk-fill resin samples presented microhardness means of 55.9 kgf/mm2, 53.7 kgf/mm2, and 49.3 kgf/mm2, the AURA bulk-fill resin samples presented microhardness means of 57,02 kgf/mm2, 55,86 kgf/mm2 e 51,77 kgf/mm2 for the distances of 2 mm, 4 mm, and 6 mm, respectively. Tukey's statistical test showed a significant difference in microhardness values at different distances of 2 mm, 4 mm, and 6 mm (p<0.001) for each resin. Although there was a statistically significant difference within and between the groups assessed, all samples showed polymerization effectiveness when comparing the top and base of the block. Conclusion: Polymerization was effective in different thicknesses (2 mm, 4 mm, and 6 mm) in both resins studied. The microhardness ratio was adequate when comparing the base and top

Analysis of color stability and degree of conversion of different types of resin composites

Abstract Resin composites containing surface pre-reacted glass (S-PRG) have been introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physicomechanical properties over time, including color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites. Discs (6 x 4 mm, n = 5/group) of microhybrid (MH), nanofilled (NF), nanohybrid (NH), and S-PRG-based nanohybrid (S-PRG-NH) composites with two opacities (A2/A2E and A2O/A2D) were prepared. Color (CIELab and CIEDE2000) was evaluated with a spectrophotometer after aging in grape juice (2 x 10 min/10mL/7days). The DC was analyzed by using Fourier transform infrared spectroscopy before and after light-curing. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (p<0.05). In the color stability analysis, the interaction between filler type and opacity was significant (CIELab, p = 0.0015; CIEDE2000, p = 0.0026). NH presented the highest color stability, which did not differ from that of MH. The greatest color alteration was observed for S-PRG-NH. S-PRG fillers also influenced DC (p < 0.05). The nanohybrid resin composite presented favorable overall performance, which is likely related to its more stable organic content. Notwithstanding the benefits of using S-PRG-based nanohybrid resins, mostly in aesthetic procedures, professionals should consider the susceptibility of such resins to color alteration, probably due to the water-based bioactive mechanism of action.

In vitro characterization of a novel resin-based restorative material containing alkaline fillers

Abstract Objective: In this study, a comparative evaluation of the physicochemical properties of Cention N and other direct restorative materials was performed. Three restorative materials—a resin-modified glass ionomer (Fuji II LC), an alkasite-based resinous material (Cention N), and a resin composite (Tetric N Ceram)—were characterized in terms of degree of conversion, Knoop hardness number (KHN) ratio, flexural strength, elastic modulus, water sorption, water solubility, microshear bond strength to dentin, immediate microleakage, and radiopacity. Methodology: The microshear bond strength to dentin and microleakage of Cention N were evaluated with and without the application of an adhesive system (Tetric N Bond Universal). A one-way ANOVA test was used to analyze the data in terms of degree of conversion, KHN ratio, water sorption, water solubility, microshear bond strength to dentin, and radiopacity. A two-way ANOVA test (carried out considering the material type and ethanol aging as factors) was used to analyze the data in terms of flexural strength and elastic modulus. The Kruskal-Wallis test was used to statistically analyze the data on microleakage. A significance level of α=0.05 was used for all tests. Results: Fuji II LC was found to have the highest degree of conversion, water sorption, and microleakage, as well as the lowest flexural strength. Cention N had the highest solubility; when used with an adhesive system, it achieved bond strength and microleakage similar to those of the Tetric N Ceram composite. Tetric N Ceram had the highest degree of conversion, KHN ratio, and radiopacity. Conclusion: The properties of Cention N validate its efficacy as an alternative direct restorative material when used in conjunction with an adhesive system.

Effect of composite radiopacity and margin location of the restoration on the diagnosis of secondary caries

Abstract This research aimed to evaluate the effect of the radiopacity of a Bulk-Fill composite (X-TraFil, VOCO, Germany) and a Conventional composite (P60, 3M ESPE, USA) and assessment of the margin location in the enamel and dentin on the diagnosis of secondary caries. 76 intact premolars with MOD preparation were divided into two equal groups and filled with the conventional and bulk-fill composite. Four regions were considered to simulate carious lesions (two regions in enamel and two regions in dentin). In each group, half of the regions in the dentin and half in the enamel were randomly selected for secondary caries simulation and filled with a wax-plaster combination while the remaining regions stayed intact. Bitewing imaging was done using the PSP digital sensor. Five examiners reviewed the images, and lesions were recorded. Caries diagnosis indicators and paired-sample t-test were used for statistical analysis. The reproducibility and accuracy of the examiners' responses were evaluated using the kappa and agreement coefficient (α=0.05). The sensitivity, specificity, and accuracy of diagnosing secondary carious lesions in enamel were significantly better under conventional than bulk-fill composite. Similarly, the sensitivity and accuracy of diagnosing secondary caries in dentin were significantly higher under conventional composite than bulk-fill composite (p<0.05). No significant differences were found in the agreement and kappa coefficient between conventional and bulk-fill composites in the enamel and dentin (p>0.05). The diagnostic accuracy of carious lesions was higher under conventional composite than bulk-fill composite. However, the location of the secondary was ineffective in caries diagnosis.

Resumo Essa pesquisa teve como objetivo avaliar o efeito da radiopacidade de resina composta Bulk-Fill (X-TraFil, VOCO, Alemanha) e de resina composta convencional (P60, 3M ESPE, EUA) e a avaliação da localização da margem no esmalte e na dentina no diagnóstico de cárie secundária. 76 pré-molares intactos com preparo MOD foram divididos em dois grupos iguais e restaurados de acordo com o grupo experimental. Quatro regiões foram consideradas para simular lesões de cárie (duas regiões no esmalte e duas regiões na dentina). Em cada grupo, metade das regiões na dentina e metade no esmalte foram selecionadas aleatoriamente para a simulação de cárie secundária e preenchidas com uma combinação de cera e gesso, enquanto as regiões restantes permaneceram intactas. As imagens de bitewing foram feitas usando o sensor digital PSP. Cinco examinadores analisaram as imagens, e as lesões foram registradas. Os indicadores de diagnóstico de cárie e o teste t de amostra pareada foram usados para análise estatística. A reprodutibilidade e a precisão das respostas dos examinadores foram avaliadas usando o kappa e o coeficiente de concordância (α=0,05). A sensibilidade, a especificidade e a precisão do diagnóstico de lesões cariosas secundárias no esmalte foram significativamente melhores com a resina composta convencional do que com a resina composta bulk-fill. Da mesma forma, a sensibilidade e a precisão do diagnóstico de cáries secundárias na dentina foram significativamente maiores com a resina convencional do que com a resina bulk-fill (p<0,05). Não foram encontradas diferenças significativas na concordância e no coeficiente kappa entre as resinas convencionais e bulk-fill no esmalte e na dentina (p>0,05). A precisão do diagnóstico de lesões cariosas foi maior com a resina composta convencional do que com a resina composta bulk-fill. Entretanto, a localização do secundário foi ineficaz no diagnóstico de cárie.

Niobium oxyhydroxide as a bioactive agent and reinforcement to a high-viscosity bulk-fill resin composite

Abstract Objective The present in vitro study incorporated niobium oxyhydroxide fillers into an experimental high-viscosity bulk-fill resin composite to improve its mechanical performance and provide it a bioactive potential. Methodology Scanning electron microscopy synthesized and characterized 0.5% niobium oxyhydroxide fillers, demonstrating a homogeneous morphology that represented a reinforcement for the feature. Fillers were weighed, gradually added to the experimental resin composite, and homogenized for one minute, forming three groups: BF (experimental high-viscosity bulk-fill resin composite; control), BF0.5 (experimental high-viscosity bulk-fill resin composite modified with 0.5% niobium oxyhydroxide fillers), and BFC (commercial bulk-fill resin composite Beautifil Bulk U, Shofu; positive control). In total, 10 specimens/groups (8 × 2 × 2 mm) underwent flexural strength (FS) tests in a universal testing machine (Instron) (500N). Resin composites were also assessed for Knoop hardness (KH), depth of cure (DoC), degree of conversion (DC), elastic modulus (E), and degree of color change (ΔE). The bioactive potential of the developed resin composite was evaluated after immersing the specimens into a simulated body fluid in vitro solution and assessing them using a Fourier-transformed infrared spectroscope with an attenuated total reflectance accessory. One-way ANOVA, followed by the Tukey's test (p<0.05), determined FS, DC, KH, and ΔE. For DoC, ANOVA was performed, which demonstrated no significant difference between groups (p<0.05). Conclusions The high-viscosity bulk-fill resin composite with 0.5% niobium oxyhydroxide fillers showed promising outcomes as reinforcement agents and performed well for bioactive potential, although less predictable than the commercial resin composite with Giomer technology.

Effect of Water and Chlorhexidine with Different Pressures of Oral Irrigation Device on the Surface Roughness and Topography of Giomer

Abstract Objective: To evaluate the effect of different pressures of an oral irrigation device (OID) and the irrigation solution type on the surface roughness of the giomer restorative material. Material and Methods: In this in vitro study, disk-shaped giomer samples were fabricated and assigned to 5 groups (n=23): Group 1, storage in distilled water (control); Group 2, OID #7 pressure/ water; Group 3, OID #10 pressure/ water; Group 4, OID #7 pressure/ 0.05% CHX; Group 5, OID #10 pressure/ 0.05% CHX. The samples' treatment simulated a one-year application of OID. Surface roughness (Ra) and topography of the giomer were evaluated using profilometry and scanning electron microscopy. The data were analyzed with Paired t-test, Tukey, and ANOVA tests (α=0.05). Results: The Ra of the samples increased significantly after treatment with OID (p<0.001). The roughness increase in groups with a pressure of 10 was higher than those with a pressure of 7 (p<0.001). The effect of pressure on surface changes was significant (p<0.001). However, the solution type and the cumulative effect of these two factors were insignificant (p=0.08 and p=0.43, respectively). Conclusion: Oral irrigation device with both solutions significantly increased the surface roughness and topographic changes of the giomer. The severity of these changes was related to the device's pressure.

Does the combination of whitening toothpaste and hydrogen peroxide bleaching increase the surface roughness and change the morphology of a nanofilled composite?

Aim: To evaluate changes in the surface roughness and morphology of a nanofilled composite following toothbrushing with a whitening (WT) or regular toothpaste (RT), alone or combined with 35% hydrogen peroxide bleaching (HP). Methods: Seventy disc-shaped nanofilled composite (Filtek Z350XT) specimens were randomly divided into groups (n=10): WT, RT, TB (without toothpaste ­ control) or the combinations WT/ HP, RT/HP, TB/HP and HP. All groups underwent toothbrushing simulation (60,000 cycles) and bleaching treatment (4 sessions). Mean surface roughness (Ra, µm) was measured before (T0) and after treatments (TB). Surface morphology was assessed by scanning electron microscopy (SEM) at TB. Mean Ra was analyzed using general mixed models and multiple comparisons by the Tukey-Kramer test (α=5%). Results: HP caused no surface roughness changes on the nanofilled composite after treatment (p>0.05). RT toothbrushing, combined or not with HP, increased the surface roughness (p<0.05). WT and WT/ HP protocols had no effect on the surface roughness of the composite (p>0.05). The nanofilled composite submitted to RT toothbrushing combined with HP (RT/HP) presented substantial surface alterations under SEM, showing deep depressions and round-shaped defects. Toothbrushing with RT combined with the bleaching agent increased exposure of the inorganic fillers. Conclusion: WT toothbrushing, regardless of HP combination, or the single HP protocol had no effect on the surface roughness of the nanofilled composite. However, RT combined with HP negatively affected surface roughness and presented the most noticeable surface changes among groups

Reliability of the color measurement of resin composites using images obtained using a stereoscopic loupe

Abstract This study assessed the reliability of a color measurement method using images obtained from a charge-coupled device (CCD) camera and a stereoscopic loupe. Disc-shaped specimens were created using the composite Filtek Z350 XT (shades DA1, DA2, DA3, and DA4) (n = 3). CIELAB color coordinates of the specimens were measured using the spectrophotometer SP60 over white and black backgrounds. Images of the same specimens were taken using a CCD camera attached to a stereoscopic loupe. The color of the image was measured (red-green-blue [RGB]) using an image processing software and converted to CIELAB coordinates. For each color coordinate, data from images were adjusted using linear regressions predicting those values from SP60. The whiteness index for dentistry (WID) and translucency parameter (TP00) of the specimens as well as the color differences (ΔE00) among pairwise shades were calculated. Data were analyzed via repeated-measures analysis of variance and Tukey's post hoc test (α = 0.05). Images obtained using the loupe tended to be darker and redder than the actual color. Data adjustment resulted in similar WID, ΔE00, and TP00 values to those observed for the spectrophotometer. Differences were observed only for the WID of shade DA3 and ΔE00 for comparing DA1 and DA3 over the black background. However, these differences were not clinically relevant. The use of adjusted data from images taken using a stereoscopic loupe is considered a feasible method for color measurement.