Effect of replacing a component of a self-etch adhesive by chlorhexidine on bonding to dentin.

The purpose of this study was to evaluate the effect of replacing a component of the self-etch adhesive Adper Scotchbond SE (liquid A + liquid B) by 2% chlorhexidine (CHX) on bond strength to dentin after 1 day, 3 months or 6 months of water storage. Eight human teeth were sectioned to expose a flat dentin surface and were then randomly assigned to 2 groups. In the control group, the dentin surfaces were treated with the adhesive according to the manufacturer's instructions. In the experimental group, liquid A was replaced by 2% CHX. Next, a 6-mm-high resin composite block was incrementally built on the bonded surfaces. The restored teeth were then sectioned to produce stick-shaped specimens (cross-sectional area - 0.8 mm2). The microtensile bond strength (µTBS) was recorded, and the failure modes were assessed. Data were analyzed by two-way repeated measures ANOVA (α=0.05). Four additional teeth were processed in order to conduct a micromorphological analysis of the resin-dentin interface. The µTBS values did not significantly decrease after water storage in either the control or the experimental group, whose values did not differ significantly irrespective of storage time. The morphological aspect of the bonding interface appears not to have been affected by CHX. A higher incidence of cohesive failures within the adhesive and mixed failures (cohesive within adhesive and resin composite) was observed for both groups. It may be concluded that dentin pre-treatment with 2% CHX did not influence significantly the bonding performance of the evaluated adhesive.

Effect of Replacing a Component of a Self-Etch Adhesive by Chlorhexidine on Bonding to Dentin

The purpose of this study was to evaluate the effect of replacing a component of the self-etch adhesive Adper Scotchbond SE (liquid A + liquid B) by 2% chlorhexidine (CHX) on bond strength to dentin after 1 day, 3 months or 6 months of water storage. Eight human teeth were sectioned to expose a flat dentin surface and were then randomly assigned to 2 groups. In the control group, the dentin surfaces were treated with the adhesive according to the manufacturer's instructions. In the experimental group, liquid A was replaced by 2% CHX. Next, a 6-mm-high resin composite block was incrementally built on the bonded surfaces. The restored teeth were then sectioned to produce stick-shaped specimens (cross-sectional area - 0.8 mm2). The microtensile bond strength (µTBS) was recorded, and the failure modes were assessed. Data were analyzed by two-way repeated measures ANOVA (α=0.05). Four additional teeth were processed in order to conduct a micromorphological analysis of the resin-dentin interface. The µTBS values did not significantly decrease after water storage in either the control or the experimental group, whose values did not differ significantly irrespective of storage time. The morphological aspect of the bonding interface appears not to have been affected by CHX. A higher incidence of cohesive failures within the adhesive and mixed failures (cohesive within adhesive and resin composite) was observed for both groups. It may be concluded that dentin pre-treatment with 2% CHX did not influence significantly the bonding performance of the evaluated adhesive.

O objetivo deste estudo foi o de avaliar o efeito da substituição de um componente do adesivo autocondicionante Adper Scotchbond SE (líquido A + líquido B) por clorexidina (CHX) a 2% na resistência da união à dentina após 1 dia, 3 meses ou 6 meses de armazenamento em água. Oito dentes humanos foram seccionados para expor uma superfície plana de dentina e, em seguida, foram aleatoriamente divididos em dois grupos. No grupo controle, as superfícies de dentina foram tratadas com o adesivo de acordo com as instruções do fabricante. No grupo experimental, o líquido A foi substituído por CHX a 2%. Em seguida, um bloco de resina composta com 6 mm de altura foi construído sobre a superfície de união. Os dentes restaurados foram então seccionados para produzir espécimes em forma de palito (área transversal - 0,8 mm2). A resistência da união à microtração (µT) foi mensurada e os padrões de fratura avaliados. Os dados foram analisados por meio de teste de ANOVA dois critérios de medidas repetidas (α=0,05). Quatro dentes adicionais foram processados a fim de realizar uma análise micromorfológica da interface resina-dentina. Os valores de µT não diminuíram significativamente após armazenamento em água em ambos os grupos controle e experimental, cujos valores não diferiram significativamente entre si independentemente do tempo de armazenamento. O aspecto morfológico da interface adesiva parece não ter sido afetado pela CHX. Uma maior incidência de falhas coesivas no adesivo e falhas mistas (coesivas no adesivo e na resina composta) foi observada em ambos os grupos. Pode-se concluir que o pré-tratamento da dentina com CHX a 2% não influenciou significativamente o desempenho do adesivo avaliado.

Effects of curing protocols on fluid kinetics and hardness of resin cements.

The effects of polymerization protocols on water sorption/solubility, the diffusion coefficient (D), the flux (J), and the hardness (KH) of two resin cements were evaluated. The materials were manipulated and divided into three groups (n=6) according to the curing protocol: PA=photoactivation (40 s); DP=delayed photoactivation (10 min self-curing plus 40 s photoactivated); CA=chemical activation. After desiccation, the specimens were weighed, stored in water (37ºC), evaluated over 28-days, and hardness recorded. Chemical activation resulted in lower net water uptake, D, and J for RelyX ARC (RX). For Variolink II (VL), CA yielded equivalent D and lower J; however, photoactivation resulted in lower net water uptake. Hardness of VL was less affected by the water storage, irrespective of the polymerization protocol. Considering the water diffusion parameters, VL demonstrated immediate photoactivation dependence; for RX, a chemical activation. Different polymerization protocols affect the fluid kinetics and the hardness of the resin cements tested.

Effect of photoinitiator concentration on marginal and internal adaptation of experimental composite blends photocured by modulated methods.

OBJECTIVE: The aim of this study was to evaluate the influence of photoinitiator concentration on marginal and internal adaptation of composites photocured by modulated methods. MATERIALS AND METHODS: Composites based on BisGMA/triethylene glycol dimethacrylate and 65 wt% of filler were prepared with different concentrations of camphorquinone/amine (C1-0.5%, C2-1%, C3-1.5%). Cavities were prepared (3 mm × 3 mm × 2 mm) on the buccal surface of 120 bovine incisors and the adhesive system Adper Single Bond 2 was applied following manufactures instruction. Specimens were then distributed according to type of composite (C1, C2, C3) and photoactivation method (high-intensity - 750 mW/cm(2) for 40 s; low intensity - 150 mW/cm(2) for 200 s; soft-start - 150 mW/cm(2) for 10 s + 750 mW/cm(2) for 38 s; pulse-delay - 150 mW/cm(2) for 10 s + 3 min dark + 750 mW/cm(2) for 38 s). Superficial and internal margins were analyzed by scanning electron microscopy, using the epoxy replica technique. The length of gaps was expressed as a percentage of the total length of the margins. Data were submitted to two-way analysis of variance and Tukey's test (α =0.05). RESULTS: Modulated curing methods did not influence gap formation regarding both superficial and internal adaptation. The composite with the lower initiator concentration (C1) presented higher gap formation when compared with those with higher concentrations (C2 and C3). CONCLUSION: Modulated photoactivation methods did not reduce gap formation for the experimental composite restorations evaluated. However, higher photoinitiator concentrations promote better marginal seal.

Bond strength and interfacial micromorphology of etch-and-rinse and self-adhesive resin cements to dentin.

PURPOSE: To evaluate the microtensile bond strength and interfacial micromorphology of indirect composite restorations to dentin using three commercial resin cements after 24 hours and 30 days of water storage. MATERIALS AND METHODS: The medium dentin of third human molars was exposed (N = 30, n = 10 per group). Three commercial resin cements were used to cement indirect resin composite restorations to dentin: the auto-cured C&B Cement/All Bond 2, the dual-cured RelyX ARC/Adper Single Bond 2, and the self-adhesive dual-cured RelyX Unicem. Teeth were sectioned after water storage at 37°C (24 hours and 30 days) to obtain beams with a bonded area of 0.8 mm(2) . The specimens were tested in a universal testing machine at a 0.5 mm/min crosshead speed. Scanning electron microscopic fractographic and interfacial micromorphology analyses were performed. Data were analyzed using two-way ANOVA and Tukey's test (α= 0.05). RESULTS: Mean bond strength (MPa) after 24 hours: C&B Cement 19.5 ± 3.8, RelyX ARC 40.8 ± 9.4, RelyX Unicem 31.3 ± 7.4; after 30 days: C&B Cement 24.5 ± 5.1, RelyX ARC 44.2 ± 8.5, RelyX Unicem 28.3 ± 7.1. The mean bond strengths of both dual-cure cements were significantly higher than that obtained with C&B Cement after 24 hours. A significant increase in the bond strength of C&B Cement was verified after 30 days, reaching values statistically equivalent to those produced by RelyX Unicem and RelyX ARC. The self-adhesive cement preserved the same level of bond strength after 30 days. Fractographic analysis revealed a prevalence of cohesive fractures in the hybrid layer for C&B Cement, mixed (cohesive in the cement, hybrid layer, and adhesive) for RelyX ARC, and cohesive in the cement for RelyX Unicem. No distinguishable hybrid layer or resin tags were observed in the interaction of RelyX Unicem with dentin. CONCLUSIONS: The particular interaction of each cement with dentin results in specific bond strength and failure patterns that varied among groups in both evaluation times. Even though the self-adhesive cement tested exhibited no authentic hybrid layer, it was able to promote reliable adhesion with the underlying dentin.

Microtensile bond strength test and failure analysis to assess bonding characteristics of different adhesion approaches to ground versus unground enamel.

This study evaluated the bonding characteristics to ground and unground enamel obtained with different strategies. For this purpose, 24 sound third-molars were bisected mesiodistally to obtain tooth halves. A flat enamel area was delimited in the tooth sections, which were randomly distributed into 8 groups (n=6), according to the enamel condition (ground and unground) and adhesive system (Adper Single Bond 2 - SB2; Adper Prompt L-Pop - PLP; Adper Prompt - AD; Clearfil SE Bond - SE). Each system was applied according manufacturers' instructions and a 6-mm-high resin composite "crown" was incrementally built up on bonded surfaces. Hourglass-shaped specimens with 0.8 mm(2) cross-section were produced. Microtensile bond strength (µTBS) was recorded and the failure patterns were classified. Results were analyzed by two-way ANOVA and Tukey's test (α=0.05). There were no statistically significant differences among the µTBS values of SB2, PLP and AD (p>0.05). SE values were significantly lower (p0.05). There was prevalence of cohesive failure within enamel, adhesive system and resin composite for SB2. The self-etch systems produced higher incidence of cohesive failures in the adhesive system. Enamel condition did not determine significant differences on bonding characteristics for the same bonding system. In conclusion, the bonding systems evaluated in this study resulted in specific µTBS and failure patterns due to the particular interaction with enamel.

Microtensile bond strength test and failure analysis to assess bonding characteristics of different adhesion approaches to ground versus unground enamel

This study evaluated the bonding characteristics to ground and unground enamel obtained with different strategies. For this purpose, 24 sound third-molars were bisected mesiodistally to obtain tooth halves. A flat enamel area was delimited in the tooth sections, which were randomly distributed into 8 groups (n=6), according to the enamel condition (ground and unground) and adhesive system (Adper Single Bond 2 - SB2; Adper Prompt L-Pop - PLP; Adper Prompt - AD; Clearfil SE Bond - SE). Each system was applied according manufacturers' instructions and a 6-mm-high resin composite "crown" was incrementally built up on bonded surfaces. Hourglass-shaped specimens with 0.8 mm² cross-section were produced. Microtensile bond strength (μTBS) was recorded and the failure patterns were classified. Results were analyzed by two-way ANOVA and Tukey's test (α=0.05). There were no statistically significant differences among the μTBS values of SB2, PLP and AD (p>0.05). SE values were significantly lower (p0.05). There was prevalence of cohesive failure within enamel, adhesive system and resin composite for SB2. The self-etch systems produced higher incidence of cohesive failures in the adhesive system. Enamel condition did not determine significant differences on bonding characteristics for the same bonding system. In conclusion, the bonding systems evaluated in this study resulted in specific μTBS and failure patterns due to the particular interaction with enamel.

Este estudo avaliou a união ao esmalte íntegro e desgastado obtida com diferentes estratégias. Para tanto, 24 terceiros molares hígidos foram seccionados ao meio. Um plano de esmalte foi delimitado nos fragmentos de dente, aleatoriamente distribuídos em 8 grupos (n=6) conforme a condição do esmalte (íntegro ou desgastado) e o adesivo (Adper Single Bond 2: SB2; Adper Prompt L-Pop: PLP; Adper Prompt: AD; Clearfil SE Bond: SE). Estes foram aplicados seguindo recomendações dos fabricantes e uma "coroa" de compósito (altura - 6 mm) incrementalmente construída. Espécimes (ampulheta/secção transversal - 0,8 mm²) foram confeccionados. O ensaio de resistência da união à micro-tração (RUµT) foi realizado e os padrões de fratura classificadas. Os resultados analisados pela ANOVA (dois fatores) e teste de Tukey (α=0,05). Os valores de RUµT do SB2, PLP e AD não foram significativamente diferentes entre si (p>0,05); SE foi inferior (p0,05). Houve prevalência de fratura no esmalte, adesivo e compósito no SB2. Nos adesivos autocondicionantes, predominou a fratura no adesivo. A condição do esmalte não influenciou significativamente as características da união, considerando o mesmo adesivo. Em conclusão, os adesivos apresentaram RUµT e padrões de fratura específicos, devido a forma de interação com o esmalte.

SEM analysis of the acid-etched enamel patterns promoted by acidic monomers and phosphoric acids

ABSTRACT OBJECTIVE: Although self-etching bonding systems (SES) are indicated to prepare dental enamel for bonding, concerns have been expressed regarding their effectiveness. The aim of this study was to analyze the etching pattern (EP) of nine SES in comparison with 35 percent and 34 percent phosphoric acid etchants (FA) on intact (IN) and ground (GR) enamel surface. MATERIALS AND METHODS: Twenty-two human third molars were sectioned in mesial-distal and buccal-lingual directions, and four dental fragments were obtained from each tooth. Half of the fragments were ground using 600-grit SiC paper and the other half remained intact. The fragments were randomly assigned into 22 groups, according to the texture of enamel surface (IN and GR) and the technique to etch the enamel (34 percent FA, 35 percent FA, AdheSE primer; Brush & Bond; Clearfil Protect Bond primer; iBond; One-up Bond F; OptiBond Solo Plus primer; Tyrian SPE primer; Unifil Bond primer and Xeno III). Conditioners were applied to IN and GR enamel surfaces, according to the manufacturer's instructions. Specimens etched with phosphoric acids were washed with water, while the surfaces treated with SES were submitted to alternate rinsing with alcohol and acetone. The specimens were dried, sputter-coated and examined under a scanning electron microscope. RESULTS: For both IN and GR enamel surfaces, the EP of 34 and 35 percent FA was deeper and more homogeneous in comparison to EP of SES, except for Tyrian SPE. The acidic monomer action of self-etching systems was more effective on GR enamel. CONCLUSION: Most of the SES are less aggressive than phosphoric acid etchants and their etching effects were reduced on intact enamel surfaces.

OBJETIVO: Apesar dos sistemas adesivos autocondicionantes (SAA) serem indicados para aplicação no esmalte dental, preocupação tem sido relatada com relação a sua efetividade. O objetivo deste estudo foi avaliar o padrão de condicionamento ácido (PCA) promovido por nove SAA e comparar ao PCA produzido pelo ácido fosfórico (35 por cento e 34 por cento - AF) no esmalte intacto (EI) ou abrasionado (EA). MATERIAIS E MÉTODOS: Vinte e dois terceiros molares humanos foram seccionados nos sentidos mésio-distal e vestíbulo-lingual, e quatro fragmentos dentais foram obtidos a partir de cada dente. Metade dos fragmentos tiveram o esmalte abrasionado com lixas de SiC (600) e a outra metade permaneceu intacta. Os fragmentos foram divididos em 22 grupos, de acordo com a textura da superfície do esmalte (EI e EA) e a técnica de condicionar o esmalte (AF 34 por cento, AF 35 por cento, AdheSE primer; Brush & Bond; Clearfil Protect Bond primer; iBond; One-up Bond F; OptiBond Solo Plus primer; Tyrian SPE primer; Unifil Bond primer e Xeno III). Os agentes condicionadores foram aplicados nos EI e EA, de acordo com as instruções dos fabricantes. Espécimes tratados com AF foram lavados com água, enquanto os dentes tratados com SAA foram tratados com banhos alternados de álcool e acetona. Os espécimes foram secos, metalizados e observados em microscopia eletrônica de varredura. RESULTADOS: Em ambas as superfícies (EI e EA), o PCA dos AF (34 e 35 por cento) foi mais profundo e homogêneo, quando comparados ao PCA produzido pelos SAA, exceto para o adesivo Tyrian SPE. A ação dos monômeros ácidos dos SAA foi mais efetiva no EA. CONCLUSÃO: A maioria dos SAA é menos agressiva que o ácido fosfórico e seus efeitos condicionadores são reduzidos em superfícies de EI.

Prevalencia del elongamiento del proceso estiloide en una población adulta totalmente desdentada / Prevalence of styloid process elongation in a complete edentulous adult population

El elongamiento y mineralización del proceso estiloide ha sido descrito en la literatura como un acontecimiento que puede ser asintomático o manifestarse como Síndrome estilo-estilohioideo o Síndrome de Eagle. Este estado se caracteriza por un conjunto de señales y síntomas, como el dolor facial leve, molestia en la deglución, limitaciones en los movimientos de cabeza, cuello y la abertura bucal, otalgia, cefalea, disfagia y vértigo que pueden ser confundidos con desorden temporomandibular. Uno de los principales recursos diagnósticos para el elongamiento del proceso estiloide es la evaluación radiográfica. El propósito de este trabajo fue investigar en la población adulta totalmente desdentada, la prevalencia de elongamiento del proceso estiloide. En este trabajo los autores analizaron 233 radiografías panorámicas del servicio de examen de la FOP-UNICAMP en pacientes adultos de ambos sexos. Fueron realizadas mediciones de las imágenes de los procesos estiloides y se consideraron elongadas las imágenes de los procesos estiloides mayores de 30 milímetros. Las imágenes que no permitieron realizar las mediciones en forma segura fueron despreciadas. Los resultados fueron organizados en tablas y divididos según los factores de edad, sexo y lado predominante. Los datos permitieron observar que de las 233 radiografías, fue posible medir 341 procesos estiloides. Los autores concluyeron que existió una mayor prevalencia de proceso estiloide elongado en individuos de sexo femenino, no ocurrió predominio en cuanto al lado de presencia del proceso estiloide en individuos entre 51 y 70 años, y una baja prevalencia entre individuos con menos de 30 años

Prevalencia del elongamiento del proceso estiloide en una población adulta totalmente desdentada / Prevalence of styloid process elongation in a complete edentulous adult population

El elongamiento y mineralización del proceso estiloide ha sido descrito en la literatura como un acontecimiento que puede ser asintomático o manifestarse como Síndrome estilo-estilohioideo o Síndrome de Eagle. Este estado se caracteriza por un conjunto de señales y síntomas, como el dolor facial leve, molestia en la deglución, limitaciones en los movimientos de cabeza, cuello y la abertura bucal, otalgia, cefalea, disfagia y vértigo que pueden ser confundidos con desorden temporomandibular. Uno de los principales recursos diagnósticos para el elongamiento del proceso estiloide es la evaluación radiográfica. El propósito de este trabajo fue investigar en la población adulta totalmente desdentada, la prevalencia de elongamiento del proceso estiloide. En este trabajo los autores analizaron 233 radiografías panorámicas del servicio de examen de la FOP-UNICAMP en pacientes adultos de ambos sexos. Fueron realizadas mediciones de las imágenes de los procesos estiloides y se consideraron elongadas las imágenes de los procesos estiloides mayores de 30 milímetros. Las imágenes que no permitieron realizar las mediciones en forma segura fueron despreciadas. Los resultados fueron organizados en tablas y divididos según los factores de edad, sexo y lado predominante. Los datos permitieron observar que de las 233 radiografías, fue posible medir 341 procesos estiloides. Los autores concluyeron que existió una mayor prevalencia de proceso estiloide elongado en individuos de sexo femenino, no ocurrió predominio en cuanto al lado de presencia del proceso estiloide en individuos entre 51 y 70 años, y una baja prevalencia entre individuos con menos de 30 años (AU)