Effect of aging and cementation systems on the bond strength to root dentin after fiber post cementation

Abstract This study evaluated the effect of aging and cementation of fiber posts using glass ionomer and resin cements on push-out bond strength, failure mode, and resin tag formation. One hundred and twenty bovine incisors were used. After post-space preparation, the specimens were randomly allocated into 12 groups (n = 10) according to the cementation system used: GC - GC Gold Label Luting & Lining); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200 and the aging periods (24 hours, 6 months, and 12 months). Slices from the cervical, middle, and apical thirds were obtained and analyzed by push-out bond strength test and confocal laser scanning microscopy. One-way ANOVA and Tukey's post-hoc test was used at a significance level of 5%. For the push-out bond strength test, no differences among GC, RU, and MC in the cervical and middle thirds were observed, regardless of the period of storage (P > 0.05). In the apical third, GC and RU showed similar bond strength but higher than other groups (P > 0.05). After 12 months, GC showed the highest bond strength (P < 0.05). Bond strength to post-space dentin decreased over time, regardless of the cementation system used. Cohesive failure was the most frequent, regardless of the period of storage, cementation system, and post-space third. Tag formation was similar among all groups. After 12 months, GC showed the highest bond strength values.

Resumo Avaliar o efeito do envelhecimento e sistemas de cimentação usando ionômero de vidro e cimentos resinosos na resistência de união à dentina após a cimentação do pino de fibra. Cento e vinte incisivos bovinos foram utilizados. Após o preparo do pós-espaço, os corpos de prova foram distribuídos aleatoriamente em 12 grupos (n = 10) de acordo com o período de envelhecimento (24 horas, 6 meses e 12 meses) e o sistema de cimentação utilizado: GC - cimento de ionômero de vidro (GC Gold Label Cimentação e Revestimento); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200. Cortes dos terços cervical, médio e apical foram obtidos e analisados por teste de resistência de união push-out e microscopia confocal de varredura a laser. ANOVA one-way e teste de Tukey foi usado a um nível de significância de 5%. Para o teste de resistência de união, não foram observadas diferenças entre GC, RU e MC nos terços cervical e médio, independentemente do período de armazenamento (P > 0,05). No terço apical, GC e RU apresentaram resistência de união semelhante, porém superior aos demais grupos (P > 0,05). Após 12 meses, o GC apresentou a maior resistência de união (P < 0,05). A resistência de união à dentina no espaço para pino diminuiu ao longo do tempo, independentemente do sistema de cimentação utilizado. A formação de tags foi semelhante entre todos os grupos. Após 12 meses, o GC apresentou os maiores valores de resistência de união.

Clinical performance of resin composite restorations placed by dental students: a retrospective, cross-sectional, and observational study

Aim: A retrospective, cross-sectional study was carried out to evaluate the performance of resin composite restorations placed by undergraduate dental students with 1 to 15 years of placement based on dental records. Methods: Four calibrated operators evaluated 498 restorations (anterior and posterior) of 120 patients according to Ryge's validated criteria (USPHS). Results: The criteria that showed the smallest changes between the types of failures were color matching, marginal discoloration and surface texture. Regarding the longevity, the surface texture showed an increase in the frequency of failures from the second time interval (3.1 to 6 years). Higher prevalence of failure was found in class II and III restorations, with secondary caries being the main reason. No significant differences were found for anatomic form, marginal adaptation, and color matching. Class V restorations showed a higher fracture rate with total displacement of the restoration, with no increase in the frequency of fracture over time. Conclusion: High rate of restoration failure was observed, possibly due to the lack of experience and skills of the students. This outcome highlight the need for continuous revision and improvements of teaching practice regarding the development of clinical competences and skills by dental students

Direct Resin Composite Restoration in Anterior Tooth: 10 Years of Clinical Follow-Up

The emergence and development of resin-based materials, such as resin composites and adhesive systems, have shifted the restorative treatment of anterior teeth with caries lesions and/or fractures. Thus, based on the disadvantages of indirect restorations, direct esthetic restorations are restorative options even for anterior teeth with exten sive loss of hard tissues. This study aimed to describe and discuss the direct resin composite restoration performed to solve the esthetic and functional impairments of the upper anterior teeth with diastemas. The upper left central incisor received total crown preparation for indirect restoration. Clinical results after 10 years were recorded. Considering the clinical characteris tics of dental restorations, it is possible to conclude that direct resin composite restorations reestablished the esthetic and functional properties satisfactorily, even in a tooth with extensive coronal destruction. The success of the restorative treatm ent was dependent on factors related to the materials´ properties, oral habits of the patient, and mostly the clinical skills of th e dental clinician.

La aparición y el desarrollo de materiales con base de resina, como las resinas compuestas y los sistemas adhesivos, han cambiado el tratamiento restaurador de los dientes anteriores con lesiones de caries y/o fracturas. Por lo tanto, en base a las desventajas de las restauraciones indirectas, las restauraciones estéticas directas son opciones de restauración, incluso para los dientes anteriores con una gran pérdida de tejidos duros. Este estudio tuvo como objetivo describir y discutir la restauración directa con resina compuesta, realizada para solucionar las deficiencias estéticas y funcionales de los dientes anteriores superiores con diastemas. El incisivo central superior izquierdo recibió preparación de corona total para restauración indirecta. Se registraron los resultados clínicos después de 10 años. Considerando las características clínicas de las restauraciones dentales, es posible concluir que las restauraciones directas en resina compuesta restablecieron las propiedades estéticas y funcionales satisfactoriamente, incluso en un diente con destrucción coronal extensa. El éxito del tratamiento restaurador dependió de factores relacionados con las propiedades de los materiales, los hábitos bucales del paciente y, sobre todo, las habilidades clínicas del odontólogo.

Influence of Bleaching Agent Containing Bioactive Glass on Color and Microhardness of Bovine Enamel

To try to reduce the deleterious effects of tooth whitening, bioactive materials have been used. Forty enamel/dentin blocks were stained on dark tea and randomly assigned into four groups (n=10): control group (unbleached), HP35 % (35 % hydrogen peroxide), BG45S5 (Bioglass 45S5® incorporated into HP35 %), and BIO (Biosilicate® incorporated into HP35 %). Colorimetric analysis and microhardness evaluation was performed at baseline, 24 hours and 7 days after the final whitening session. Two-way ANOVA for repeated measures and Bonferroni test was used at a significance level of 5 %. All the coordinates (ΔL*, Δa*, Δb*, ΔE00 and WID) showed a difference between the control group and the experimental ones (p0.05), which suggest a color stability over a week. In contrast, after 7 days, the WID showed that control and PH35 % were different than the other groups (p 0.05). The microhardness did not change over time (p>0.05), except for 35 % HP. In conclusion Bioglass 45S5® and Biosilicate® prevented enamel damage without negatively affect the whitening efficacy.

Para intentar reducir los efectos nocivos del aclaramiento dental, se han usado materiales bioactivos. Cuarenta bloques de esmalte/dentina se tiñeron con té oscuro y se asignaron al azar en cuatro grupos (n=10): grupo de control (sin blanquear), HP35% (peróxido de hidrógeno al 35 %), BG45S5 (Bioglass 45S5® incorporado en HP35%) y BIO (Biosilicato® incorporado a HP35%). El análisis colorimétrico y la evaluación de la microdureza se realizaron al inicio del estudio, 24 horas y 7 días después de la última sesión de blanqueamiento. Se utilizó ANOVA de dos vías para medidas repetidas y la prueba de Bonferroni a un nivel de significancia del 5 %. Todas las coordenadas (ΔL*, Δa*, Δb*, ΔE00 y WID) mostraron diferencia entre el grupo control y el experimental (p0.05), lo que sugiere una estabilidad del color durante una semana. En cambio, a los 7 días, el WID mostró que el control y el PH35 % eran diferentes a los demás grupos (p 0.05). La microdureza no cambió con el tiempo (p>0.05), excepto para 35 % HP. En conclusión Bioglass 45S5® y Biosilicate® previnieron el daño del esmalte sin afectar negativamente la eficacia del blanqueamiento.

Conservative Approach of Fractured Tooth with 7-Years of Clinical and Radiographical Follow-Up: Case Report

ABSTRACT: Clinical and radiographical diagnosis is crucial to treat a tooth with transverse root fracture (TRF) due to dental trauma (DT). This paper aimed to report a clinical case of TRF at the cervical third of tooth 21 injured by recurrent DT with 7 years of follow-up. A 7-years old female patient was referred to dental care after the first episode of DT in 2014. Base d on the radiographical examination, splinting of teeth 11 and 21 was performed using resin composite. After 11 months, the splint was removed and the patient was discharged. In 2015, the patient suffered a second DT of the same tooth. The clinical approach was splinting the traumatized tooth using orthodontic wire and resin composite. In 2018, a third episode of DT occurred. Then, the dental staff chose to maintain the splint and evaluate the case in a long-term. In 2021, based on bone tissue condition, dental fragment stability and radiographical follow-up, the splint was removed. The patient remains under regular follow up evaluations. It can be concluded that a conservative approach in cases of TRF, when possible, can preserve biological tissues.

RESUMEN: El diagnóstico clínico y radiográfico es fundamental para tratar un diente con fractura radicular transversa (FRT) por traumatismo dentario (DT). Este trabajo tuvo como objetivo reportar un caso clínico de FRT en el tercio cervical del diente 21 lesionado por DT recurrente con 7 años de seguimiento. Una paciente de 7 años de edad fue remitida a atención odontológica luego del primer episodio de DT en 2014. Con base en el examen radiográfico, se realizó la ferulización de los dientes 11 y 21 con resina compuesta. A los 11 meses se retiró la férula y se dio de alta al paciente. En 2015, el paciente sufrió un segundo DT del mismo diente. El abordaje clínico fue la ferulización del diente traumatizado utilizando alambre de ortodoncia y composite de resina. En 2018 ocurrió un tercer episodio de DT. Luego, el personal dental optó por mantener la férula y evaluar el caso a largo plazo. En 2021, en base al estado del tejido óseo, estabilidad de los fragmentos dentarios y seguimiento radiográfico, se procedió a la retirada de la férula. El paciente permanece bajo evaluaciones regulares de seguimiento. Se puede concluir que un abordaje conservador en casos de TRF, cuando sea posible, puede preservar los tejidos biológicos.

Influence of F-18 Bioactive Glass Incorporation into Whitening Gel on Properties of Bovine Dental Enamel

ABSTRACT: Bioactive materials have shown positive results in reducing the deleterious effects of tooth whitening. However, their effects on whitening efficacy is still uncertain. Therefore, the aim of this study was to evaluate the effects of F- 18 bioactive glass incorporation into a bleaching gel on color and microhardness of enamel after tooth whitening. Thirty bovine enamel-stained specimens were randomly divided into three groups (n=10) according to the whitening protocol: control group (unbleached), HP35 % (35 % hydrogen peroxide) and F-18 (F-18 bioactive glass incorporated into HP35 %). pH, color change and microhardness analyzes were performed at baseline, 24 hours and 7 days after tooth whitening. Color evaluation showed that experimental groups were different than control group for all coordinates (p 0.05). No differences in enamel microhardness were found among the groups within the same evaluation time (p > 0.118). Regarding the intragroup comparisons, no differences were observed for control and F-18 groups (p > 0.129). It was concluded that F-18 bioactive glass incorporation did not affect the whitening efficacy and the enamel microhardness.

RESUMEN: Los materiales bioactivos han mostrado resultados positivos en la reducción de efectos nocivos del aclaramiento dental. Sin embargo, sus efectos sobre la eficacia del aclaramiento aún son inciertos. Por lo tanto, el objetivo de este estudio fue evaluar los efectos de la incorporación de vidrio bioactivo F-18 en un gel aclarador sobre el color y la microdureza del esmalte después del aclariamiento dental. Treinta especímenes bovinos teñidos con esmalte se dividieron aleatoriamente en tres grupos (n=10) de acuerdo con el protocolo de aclaramiento: grupo control (sin aclaramiento), HP35 % (peróxido de hidrógeno al 35 %) y F-18 (vidrio bioactivo F-18 incorporado en HP35 %). Se realizaron análisis de pH, cambio de color y microdureza al inicio del estudio, 24 horas y 7 días después del aclaramiento dental. La evaluación del color mostró que los grupos experimentales eran diferentes al grupo de control en todas las coordenadas (p 0,05). No se encontraron diferencias en la microdureza del esmalte entre los grupos dentro del mismo periodo de evaluación (p > 0,118). En cuanto a las comparaciones intragrupos, no se observaron diferencias para los grupos control y F-18 (p > 0,129). Se concluyó que la incorporación de vidrio bioactivo F-18 no afectó la eficacia de aclaramiento ni la microdureza del esmalte.

Violet LED-Based Tooth Whitening and Resin Composite Restorations to Reestablish Smile Aesthetics Case Report

ABSTRACT: This clinical case described the aesthetic treatment of a patient complaining about the aspect of their upper teeth. After anamnesis and clinical examination, the association of tooth whitening photoactivated by violet LED and resin composite restorations was indicated. Prior to restorative treatment, three bleaching sessions were performed with low concentration hydrogen peroxide (6 %; Nano white flex) for 30 minutes. During this period, violet LED irradiation was intercalating performed every 1 minute, totalizing 15 minutes. Ten days after the final bleaching session, old restorations in the upper lateral incisors were removed for better color selection of resin composites. Then, all upper anterior teeth were directly restored with nanofilled resin composite (Filtek Z350XT), reestablishing anatomy, form, and function. At the end of the treatment, the association of techniques proved to be cost-effective, restoring the esthetics satisfactorily and promoting the patient's well-being by a minimally invasive approach.

RESUMEN: En este reporte de caso se describió el tratamiento para una paciente que se quejaba del aspecto de sus dientes superiores. Tras anamnesis y exploración clínica, se indicó la asociación de blanqueamiento dental fotoactivado por LED violeta y restauraciones de resina compuesta. Antes del tratamiento restaurador, se realizaron tres sesiones de blanqueamiento con peróxido de hidrógeno de baja concentración (6 %; Nano white flex) durante 30 minutos. Durante este período, la irradiación con LED violeta se intercalaba cada 1 minuto, totalizando 15 minutos. Diez días después de la última sesión de blanqueamiento, se retiraron las restauraciones antiguas de los incisivos laterales superiores para una mejor selección del color de la resina compuesta. Luego, todos los dientes anteriores superiores fueron restaurados de manera directa con resina de nanorrelleno (Filtek Z350XT), restableciendo la anatomía, forma y función. Al final del tratamiento, la asociación de las técnicas resultó beneficioso, restaurando la estética de forma satisfactoria y promoviendo el bienestar de la paciente mediante un abordaje mínimamente invasivo.

Ultrasound device as a minimally invasive approach for caries dentin removal

Abstract The aim of this study was to evaluate the efficacy of an ultrasound device and the dentin surface morphology after removal of the caries dentin lesions by removal rate and scanning electron microscopy (SEM). The Knoop hardness test on the bovine dentin blocks (n = 20, 4x4x2mm) was performed to standardize the samples and only those with 38 ± 2 KHN were included. The dentin blocks were submitted to induction of artificial caries lesions, using the bacterial model. Strains of Streptococcus mutans and Lactobacillus acidophilus were used for 7 days. The caries dentin lesion was removed for 1 min, according to two methods: G1 - carbide bur under low-speed rotation (control group) and G2 - ultrasound device under refrigeration. For the removal rate, the samples were weighed 3 times: T0 (before induction), T1 (after induction) and T2 (after removal). Morphology evaluation of the residual dentin surface was performed by SEM. Data normality was verified by Shapiro-Wilk test (p ≥ 0.240). T-test for independent samples was applied to evaluate the removal rate. A significance level of 5% was adopted. G2 provided lower removal rate than G1 (G1: 3.68 mg and G2 = 2.26 mg). SEM images showed different morphological characteristics between the groups. G2 showed absent of smear layer, while G1 showed a visible smear layer over the surface. We concluded that ultrasound device provides minimally invasive removal with residual dentin exhibiting open dentin tubules and no smear layer formation and no bacteria, which infer the removal of the infected tissue.

Resumo O objetivo deste estudo foi avaliar a eficácia de um dispositivo ultrassônico e a morfologia da superfície dentinária após a remoção da dentina cariada por meio da taxa de remoção e imagens de microscopia eletrônica de varredura (MEV). Foi realizado o teste de dureza Knoop nas amostras de dentina bovina (n = 20, 4x4x2mm) afim de padronizar as amostras e foram incluídas apenas aquelas com 38 ± 2 KHN. As amostras de dentina foram submetidas à indução de lesões artificiais de cárie, utilizando-se modelo biológico contendo cepas de Streptococcus mutans e Lactobacillus acidophilus durante por 7 dias. As lesões foram removidas por 1 min, de acordo com dois métodos: G1 - fresa esférica sob baixa rotação (grupo controle) e G2 - dispositivo ultrassônico sob refrigeração. Para a taxa de remoção, as amostras foram pesadas em três tempos: T0 (antes da indução), T1 (após a indução) e T2 (após a remoção). A avaliação morfológica da superfície residual da dentina foi realizada por MEV. A normalidade dos dados foi verificada pelo teste de Shapiro-Wilk (p ≥ 0,240). Teste T para amostras independentes foi aplicado para avaliar a taxa de remoção. Foi adotado nível de significância de 5%. G2 apresentou menor taxa de remoção que G1 (G1: 3,68 mg e G2 = 2,26 mg). As imagens de MEV mostraram características morfológicas diferentes entre os grupos. G2 mostrou ausência de smear layer, enquanto G1 mostrou grande quantidade de smear layer sobre a superfície. Com base neste estudo in vitro, o dispositivo de ultrassom promoveu remoção minimamente invasiva e dentina residual exibindo túbulos dentinários abertos e mínima formação de smear layer.

Blue Covarine Toothpaste versus Office Whitening: Which is the Most Effective on Stained Teeth? / Creme Dental de Blue Covarine Versus Clareamento de Consultório: Qual é o Mais Efetivo em Dentes Pigmentados?

Alternative whitening strategies to hydrogen peroxide have been proposed, such as the inclusion of abrasive and/or pigmented particles in the toothpaste. This study compared the whitening effectiveness of a toothpaste containing Blue Covarine (BC) vs. an in-office whitening treatment using 35% hydrogen peroxide (HP) in teeth stained. Bovine incisors blocks (6.0x6.0x2.0 mm) were stained with green tea (GT), orange soda (OS), or red wine (RW). The samples were randomly assigned into 8 groups (n=15), according to the type of staining and whitening treatment: G1 ­ no staining, BC (Control); G2 ­ no staining, HP (Control); G3 ­ GT, BC; G4 ­ GT, HP; G5 ­ OS, BC; G6 ­ OS, HP; G7 ­ RW, BC; G8 ­ RW, HP. Color change (ΔE), luminosity (L*), green-red axis (a*), and blue-yellow axis (b*) were recorded with spectroscopy at T0 ­ baseline, T1 ­ immediately after toothbrushing or in office tooth whitening, and T2 ­ after the conclusion of the treatments. The whiteness index for dentistry (WID) was calculated. Data were analyzed by two-way repeated measured mixed ANOVA and Bonferroni test (α=0.05). HP showed a better whitening performance (ΔE) (p ≤ 0.042). Otherwise, no effects of the whitening agent were observed (p = 1.000). Data from ΔL, Δa, and Δb showed statistically significant differences for experimental groups (p < 0.001). In the WID analysis, BC and HP had similar effects within control and RW groups. In conclusion, blue covarine toothpaste may be a viable option for extrinsically stained teeth. However, for severe staining, HP-based whitening agents proved to be the most effective treatment strategy. (AU)

Estratégias de clareamento alternativas ao peróxido de hidrogênio têm sido propostas, como a inclusão de partículas abrasivas e/ou pigmentadas nos cremes dentais. Este estudo comparou a eficácia clareadora de um creme dental contendo Blue Covarine (BC) com um tratamento de clareamento em consultório com peróxido de hidrogênio a 35% (HP) em dentes pigmentados. Blocos de incisivos bovinos (6,0x6,0x2,0 mm) foram pigmentados com chá verde (GT), refrigerante de laranja (OS) ou vinho tinto (RW). As amostras foram distribuídas aleatoriamente em 8 grupos (n = 15), de acordo com o tipo de pigmento e tratamento clareador: G1 - sem coloração, CB (Controle); G2 - sem coloração, HP (Controle); G3 - GT, BC; G4 - GT, HP; G5 - OS, BC; G6 - SO, HP; G7 - RW, BC; G8 - RW, HP. Mudança de cor (ΔE), luminosidade (L *), eixo verde-vermelho (a*) e eixo azul-amarelo (b*) foram registrados com espectroscopia em T0 - baseline, T1 - imediatamente após a escovação ou clareamento dental em consultório, e T2 - após a conclusão dos tratamentos. O índice de brancura para odontologia (WID) foi calculado. Os dados foram analisados por ANOVA mista de duas vidas para medidas repetidas e teste de Bonferroni (α = 0,05). HP apresentou melhor desempenho de clareamento (ΔE) (p ≤ 0,042). Os dados de ΔL, Δa e Δb mostraram diferenças estatisticamente significativas para os grupos experimentais (p <0,001). Na análise WID, BC e HP tiveram efeitos semelhantes nos grupos controle e RW. Em conclusão, o creme dental covarine azul pode ser uma opção viável para dentes com coloração extrínseca. No entanto, para manchas graves, os agentes de clareamento à base de HP provaram ser a estratégia de tratamento mais eficaz. (AU)