The Effect of CAD/CAM Crown Material and Cement Type on Retention to Implant Abutments.

PURPOSE: To evaluate the pullout resistance of CAD/CAM implant-supported crowns cemented with provisional and definitive cements on Ti-base implant abutments. MATERIALS AND METHODS: Sixty crowns were milled for use in Ti-base implant abutments and divided (n = 15/group) according to material, as follows: (a) [Pr] Temporary acrylic resin; (b) [Co-Cr] Cobalt-Chromium alloy; (c) [Zr] polycrystalline zirconia; and (d) [Ti] titanium. The cementation was performed with RelyX Temp NE (RxT) cement or RelyX U200 self-etching resin cement, under a 50 N (5 kg) load for 10 minutes. Twenty-four hours after cementation, the crowns were subjected to the pullout test in a universal test machine, at a 1.0 mm/min crosshead speed. The tests were performed first without cement to evaluate frictional resistance (Baseline), then with provisional cement (RelyX Temp NE without cement again (Baseline After RxT), and finally with resin cement (U200). The results were analyzed by ANOVA and Tukey test (p < 0.05). RESULTS: Data evaluation as a function of cement type demonstrated the superiority of resin-based cements relative to provisional and baseline groups (p < 0.01). While Co-Cr crowns presented the highest pullout strength values, Pr showed the lowest values (data collapsed over cement) (p < 0.001). Retentiveness data as a function of both factors demonstrated similar pullout resistance between groups without cement (p < 0.001), except Zr baseline. Also, Co-Cr presented higher pullout strength compared to other materials. CONCLUSIONS: Self-adhesive resin cement exhibited superior retention compared to temporary cement, regardless of crown material. Co-Cr and titanium presented higher levels of retention to Ti-base abutment after being cemented.

Effect of aging and testing method on bond strength of CAD/CAM fiber-reinforced composite to dentin.

OBJECTIVES: To evaluate and compare the outcomes of shear (S) and microtensile (µT) bond strength tests of CAD/CAM fiber-reinforced composite (FRC) to dentin. Aging with either fatigue or thermocycling were conducted for comparison with baseline microtensile group. METHODS: CAD/CAM FRC (Trinia, Bicon LLC, Boston, USA) blocks were milled to 3-mm diameter cylinders for shear and to blocks (5×5×5mm) for µT. Sixty extracted human molars were flattened to obtain dentin surfaces and randomly divided in four groups (n=15): (1) SC: samples tested in shear 24h after bonding; (2) µTC: samples tested in µT 24h after bonding); (3) µTF: samples submitted to mechanical fatigue prior to µT test, and; (4) µTT: thermocycling prior to µT test. Bonding system was applied onto the FRC material (Cera-Resin Bond, CRB, Shofu Dental, Kyoto, Japan). A conventional three-step adhesive system (All-bond 3, Bisco, Schaumburg, USA) was use with a self-cure resin cement (C&B resin cement, Bisco, Schaumburg, USA). Bond strength tests were conducted at 0.75mm/min and data analyzed using Weibull distribution (p<0.05). RESULTS: Weibull contour plots showed a significantly lower characteristic strength (η) and Weibull modulus (m) for SC (η=6.9MPa and m=1.4) compared to µTC (η=20.9MPa and m=4.5). Fatigued and thermocycled µT groups presented significantly reduced characteristic strength (η=3.1MPa and η=4.1MPa, respectively) compared to µTC. Weibull modulus was significantly reduced only for SC and µTF groups compared µTC. Failure predominantly occurred at the cement/FRC interface. SIGNIFICANCE: FRC bonded to dentin samples presented lower Weibull modulus and characteristic bond strength when immediately tested in shear compared to microtensile. Aging through thermocycling or mechanical fatigue significantly reduced the characteristic strength in microtensile testing, with the majority of failures emerging between restoration material and cement interface.

Effect of ethanol-dissolved rhodamine B marker on mechanical properties of non-simplified adhesives.

OBJECTIVES: Rhodamine B (RB) is commonly used to evaluate dental polymers, including dental bonding systems (DBS). For reliability assessments, its effect should not only allow visualization of the dentin-polymer interface but also must not interfere with the bonding of the DBS to dentin as measured by the microtensile bond strength and hardness tests. MATERIAL AND METHODS: Flat human dentin surfaces were prepared and randomly distributed (n = 10) into six groups: Adper Scotchbond Multi-Purpose (MP) or Clearfil SE Bond (SE) in concentrations of none/control, 0.02 or 0.1 mg/mL. These combinations were prepared through ethanol dissolution to improve their penetration into the dentin. All specimens were fabricated with Filtek Z250 (n = 10) and prepared for a microtensile bond test (µTBS) (0.5 mm/min) after 7 days and 6 months. The failure modes were determined using a stereomicroscope (×40). For the hardness test, flat human dentin blocks were prepared and treated as previously described (n = 6). The specimens were stored at 37 °C/48 h and were tested (Knoop indenter - 25 gF/10 s). Data were analyzed with two-way ANOVA and Tukey tests for multiple comparisons (α = 0.05). The effect of time was evaluated using the Student t-test. RESULTS: For 7-day µTBS, both the DBS and RB concentrations were significant factors (p < 0.01). After 6 months, only the RB concentration was significantly different. Adhesive failures were prevalent for all groups. Regarding hardness, the DBS differed only with the use of 0.10 mg/mL of RB. CONCLUSIONS: Ethanol-dissolved rhodamine B in concentrations of 0.02 and 0.10 mg/mL in non-simplified adhesives can affect the physical-mechanical properties of functional monomer-based systems rather more than those of BisGMA systems.

Influence of Erosive and Abrasive Cycling on Bonding of Different Adhesive Systems to Enamel: An In situ Study.

This study evaluated the impact of orange juice on the bond strength (BS) of dentin bonding systems (DBSs) to enamel surface after simulation with an in situ/ ex vivo erosive cycling. One hundred and ninety two bovine enamel fragments (4x4x2mm) were obtained and randomized regarding superficial microhardness and distributed to palatal devices for 8 volunteers, in three phases (one for each DBS), containing 8 blocks, which were, allocated in 4 pairs. Daily, these pairs were subjected extraorally to the following conditions: CONT- neither erosive nor abrasive challenge; ERO- erosive challenge only; ABR- abrasive challenge only and ERO + ABR- with erosive and abrasive challenges. Erosive cycles (immersion in orange juice, 3 times/day/5 min/5 days) or/and abrasive challenges (electric toothbrush, 3 times/day/1 min/5 days) were performed. After these cycles, all specimens were restored with the adhesive systems Adper Scotchbond Multi Purpose (MP), Adper Single Bond 2 (SB) or Clearfil SE Bond (SE), and the composite resin Filtek Z250. After 7 days, sticks (area ≅1 mm2) were obtained and subjected to the microtensile bond strength test (µTBS) at 0.5 mm/min. Data was statistically analyzed by ANOVA and Tukey tests (a=0.05). Failure modes were determined using a digital microscope (40´). DBS was the only statistical significant factor. SE was the unique DBS not affected in any challenge, whereas MP and SB performed according to the scenario. The adhesive and mixed failures were predominant in all groups. Overall performance suggested that BS to enamel after erosive /abrasive challenged by orange juice was not affected and it was material-dependent.

Influence of Erosive and Abrasive Cycling on Bonding of Different Adhesive Systems to Enamel: An In situ Study

Abstract This study evaluated the impact of orange juice on the bond strength (BS) of dentin bonding systems (DBSs) to enamel surface after simulation with an in situ/ ex vivo erosive cycling. One hundred and ninety two bovine enamel fragments (4x4x2mm) were obtained and randomized regarding superficial microhardness and distributed to palatal devices for 8 volunteers, in three phases (one for each DBS), containing 8 blocks, which were, allocated in 4 pairs. Daily, these pairs were subjected extraorally to the following conditions: CONT- neither erosive nor abrasive challenge; ERO- erosive challenge only; ABR- abrasive challenge only and ERO + ABR- with erosive and abrasive challenges. Erosive cycles (immersion in orange juice, 3 times/day/5 min/5 days) or/and abrasive challenges (electric toothbrush, 3 times/day/1 min/5 days) were performed. After these cycles, all specimens were restored with the adhesive systems Adper Scotchbond Multi Purpose (MP), Adper Single Bond 2 (SB) or Clearfil SE Bond (SE), and the composite resin Filtek Z250. After 7 days, sticks (area ≅1 mm2) were obtained and subjected to the microtensile bond strength test (μTBS) at 0.5 mm/min. Data was statistically analyzed by ANOVA and Tukey tests (a=0.05). Failure modes were determined using a digital microscope (40´). DBS was the only statistical significant factor. SE was the unique DBS not affected in any challenge, whereas MP and SB performed according to the scenario. The adhesive and mixed failures were predominant in all groups. Overall performance suggested that BS to enamel after erosive /abrasive challenged by orange juice was not affected and it was material-dependent.

Resumo Este estudo avaliou o impacto de suco de laranja na resistência de união (RU) de sistemas adesivos dentinários (SAD) à superfície do esmalte após a simulação com uma ciclagem erosiva in situ/ex vivo. Cento e noventa e dois fragmentos de esmalte bovino (4x4x2mm) foram obtidos e randomizados considerando a microdureza superficial, e distribuídos em dispositivos palatinos para 8 voluntários, em três fases (uma para cada SAD), contendo 8 blocos, os quais foram alocados em 4 pares. Diariamente, esses pares eram submetidos às seguintes condições extraoralmente: CONT- sem desafio erosivo ou abrasivo; ERO- desafio erosivo somente; ABR- desafio abrasivo somente; e ERO+ABR- com desafio erosivo e abrasivo. A ciclagem erosiva (imersão em suco de laranja, 3 vezes/dia/5 min/5 dias) e/ou ciclagem abrasiva (escova dentária elétrica, 3 vezes/dia/1 min/5 dias) foram feitas. Após estas ciclagens, todos os espécimes foram restaurados com os sistemas adesivos Adper Scotchbond Multi Purpose (MP), Adper Single Bond 2 (SB) ou Clearfil SE Bond (SE), e com a resina composta Filtek Z250. Após 7 dias, palitos (área ≈1 mm) eram obtidos e submetidos ao teste de resistência de união por microtração (μTBS) a 0,5 mm/min. Os dados foram estatisticamente analisados por ANOVA e teste de Tukey (a=0,05). Os modos de fratura foram determinados utilizando um microscópio digital (40×). SAD foi o único fator estatisticamente significante. SE foi o único SAD não afetado por qualquer desafio, enquanto o MP e o SB apresentaram um desempenho de acordo com o cenário. As fraturas do tipo mista e adesiva foram predominantes em todos os grupos. O desempenho geral sugeriu que RU ao esmalte após desafio erosivo/abrasivo por suco de laranja não foi afetada e foi material-dependente.

How erosive drinks and enzyme inhibitors impact bond strength to dentin.

Concern has been raised about the bonding of restorative procedures to an erosive lesion, given the change in organic and inorganic composition and structure of this substrate. This in vitro study evaluated the effect of erosive drinks and an enzyme inhibitor (2% chlorhexidine digluconate - 2% CHX) on bond strength to dentin. Sixty sound human third molars were selected, and the occlusal enamel was flattened, exposing the dentin surface. The specimens were randomly divided into three groups: AS-Artificial saliva (control group), RC- Regular Cola and ZC- Zero Cola. Twenty specimens were immersed in their respective solution for 1 minute, 3 times a day, over the course of 5 days. After acid etching and before bonding with Adper Single Bond 2, half of the samples of each group (n = 10) were treated with 2% CHX, whereas the other half (n = 10) were not, forming the control group (CONV). All the specimens were restored with Filtek Z250 composite resin filled in Tygon tubes (0.48 mm2), yielding six microcylinders for microshear bond strength testing. Three composite resin microcylinders of each specimen were tested after 1 month, and the remaining microcylinders were tested after 6 months. Failure modes were determined using a stereomicroscope (40x). The data were statistically analyzed by three-way ANOVA and Tukey tests (α = 0.05). Overall bonding was reduced after 6 months, regardless of treatment. The 2% CHX enhanced bond strength after 1 month only in the ZC group, and did not enhance bonding performance to demineralized dentin by erosive protocol after 6 months in any group.

How erosive drinks and enzyme inhibitors impact bond strength to dentin

Concern has been raised about the bonding of restorative procedures to an erosive lesion, given the change in organic and inorganic composition and structure of this substrate. This in vitro study evaluated the effect of erosive drinks and an enzyme inhibitor (2% chlorhexidine digluconate – 2% CHX) on bond strength to dentin. Sixty sound human third molars were selected, and the occlusal enamel was flattened, exposing the dentin surface. The specimens were randomly divided into three groups: AS-Artificial saliva (control group), RC- Regular Cola and ZC- Zero Cola. Twenty specimens were immersed in their respective solution for 1 minute, 3 times a day, over the course of 5 days. After acid etching and before bonding with Adper Single Bond 2, half of the samples of each group (n = 10) were treated with 2% CHX, whereas the other half (n = 10) were not, forming the control group (CONV). All the specimens were restored with Filtek Z250 composite resin filled in Tygon tubes (0.48 mm2), yielding six microcylinders for microshear bond strength testing. Three composite resin microcylinders of each specimen were tested after 1 month, and the remaining microcylinders were tested after 6 months. Failure modes were determined using a stereomicroscope (40x). The data were statistically analyzed by three-way ANOVA and Tukey tests (α = 0.05). Overall bonding was reduced after 6 months, regardless of treatment. The 2% CHX enhanced bond strength after 1 month only in the ZC group, and did not enhance bonding performance to demineralized dentin by erosive protocol after 6 months in any group.

Bond strength of a resin composite and a resin-modified glass-ionomer cement associated or not with chlorhexidine to eroded dentin / Resistência de união de uma resina composta e um cimento de ionômero de vidro modificado por resina com e sem a aplicação de clorexidina à dentina erodida

Objetivo: Apesar da resina composta e o cimento de ionômero de vidro serem amplamente usados para restaurações cervicais, sob condições erosivas estas podem desgastar mais rapidamente. Este estudo objetivou comparar a resistência adesiva ao microcisalhamento de uma resistência de união (RC) e um cimento de ionômero de vidro modificado por resina (RMGIC) à dentina erodida associada à Clorexidina 2% num período de até 6 meses. Material e Métodos: Oitenta terceiros molares humanos foram cortados e uma dentina regular foi obtida, e subsequentemente, foram inclusos com resina acrílica em tubos de PVC. Os dentes foram divididos em dois grupos, de acordo com o tratamento recebido: Adper Single Bond 2 + RC Filtek Z250 (Z) ou RMGIC Vitremer (V). Metade dos corpos de prova foram imersos em saliva artificial (AS) por 24 h (grupo controle) e metade foi erodido artificialmente 3x/1 min diariamente com Coca Cola ®-RC por 5 dias. Metade dos corpos de prova, para cada condição descrita, recebeu água e outra metade a clorexidina 2% por 1 min, antes da restauração. Para todos os grupos, os corpos de prova foram armazenados em saliva artificial renovada semanalmente até os testes. A resistência de união ao microcisalhamento foi avaliado após 1 e 6 meses. Os resultados foram analisados com teste ANOVA 4 critérios e Tukey (p < 0,05). Resultados: Os fatores materiais, substrato e tempo foram estatisticamente significantes, além da interação entre o material e o tempo. O tratamento (água X clorexidina) não foi um fator significante. As restaurações com Z demonstraram resistência de união significantemente maior comparada ao V, em todas as situações. Conclusão: Tanto para a dentina sadia quanto erodida, a resina composta apresentou maior resistência de união comparada ao cimento de ionômero de vidro. O tempo e uso da clorexidina não interferiu na resistência de união. A resina composta demonstrou maior resistência adesiva quando comparada ao cimento de ionomero de vidro.

Objective: Although resin composites and glassionomer cements are widely used for dental cervical region restorations, under erosive condition they can wear out quickly. This study aimed to compare, by means of microshear bond strength, the performance of a resin composite (RC) and a resin-modified glassionomer cement (RMGIC) to eroded dentin and its association with 2% chlorhexidine (CHX) up to 6 months. Material and Methods: Eighty sound third molars teeth were cut to obtain flat coronal dentin, which were subsequently embedded in self-curing acrylic resin circular molds. Teeth were divided into two groups, according to the treatment with the Adper Single Bond 2 + RC Filtek Z250 (Z) or the RMGIC Vitremer (V). Half of the specimens were immersed in artificial saliva-AS (control groups) and half subjected to 3x/1 min daily immersion in Regular Coca Cola ®-RC for 5 days. Half of the specimens for each described condition were treated with water and half with 2% chlorhexidine for 1 min prior the restoration. For all groups, the specimens were stored in artificial saliva weekly renewed up to tests. The microshear bond strength was evaluated after 1 month and 6 months. Data, in normal distribution, were analyzed with four-way ANOVA and Tukey (p < 0.05). Results: The factors materials, substrate and time were statistically significant and also the interaction between material and time. Treatment (water x CHX) was not a significant factor. Restorations with Z showed significantly higher bond strength compared to V in all situations. There was a reduction in bond strength values over time for all tested conditions. Conclusion: For both sound and eroded dentin, the resin composite presented higher bond strength compared to resin-modified glassionomer material. The bond strength performance was overall reduced with time and the use of chlorexidine itself did not interfere on bond strength through time...

Análise do efeito de adição do marcador Rodamina B em propriedades mecânicas de sistemas adesivos não simplificados / Analysis of the effect of addition of Rhodamine B marker on mechanical properties of non-simplified adhesives

Este estudo in vitro avaliou o efeito da adição de rodamina B dissolvida em etanol nas concentrações de 0,02mg/mL e 0,10mg/mL, nas propriedades mecânicas dos sistemas adesivos não simplificados considerados padrão-ouro. 96 coroas de terceiros molares humanos hígidos foram seccionadas transversalmente no terço oclusal para remoção do esmalte e exposição da dentina. Os espécimes foram divididos de acordo com os sistemas adesivos Adper Scotchbond Multi-Purpose (MP) - convencional de três passos ou Clearfil SE Bond (SE) - autocondicionante de dois passos: MP-C e SE-C (MP e SE controles); MP-C1 e SE-C1 (MP e SE com rodamina B 0,02mg/mL); MP-C2 e SE-C2: (MP e SE com rodamina B 0,10mg/mL). Para o teste de RU, os espécimes (n=10) foram submetidos ao desgaste com lixas de granulação 320 e 600. A dentina foi tratada de acordo com as instruções de cada fabricante dos sistemas adesivos e restaurada com resina composta FiltekTM Z250. Após o armazenamento em saliva artificial (7dias/37oC), os espécimes foram seccionados para obtenção de palitos com 0,64 mm2 de área média e submetidos ao teste de microtração em máquina de teste universal a 0,5 mm/min, que foram analisados após 7 dias e 6 meses. O modo de fratura dos espécimes foi analisado com estereomicroscópio digital (x200) e classificado em: adesiva, coesiva em dentina, coesiva em resina e mista. Para o teste de MS, as coroas seccionadas (n=6) foram planificadas com lixa de granulação 600. A dentina foi tratada de acordo com as instruções de cada fabricante dos sistemas adesivos e os espécimes foram mantidos secos em estufa a 37oC durante 48 horas. O teste de MS foi realizado utilizando ponta Knoop (Microdurômetro Shimadzu HMV-2), a 10x e carga estática de 25gF por 10 segundos. Os resultados obtidos foram analisados por análise de variância (ANOVA-2 critérios) e teste de Bonferroni para comparações múltiplas (p<0,05). A análise de acordo com o tempo foi realizada com o teste de t-student. Os valores médios de RU...

This in vitro study evaluated the effect of addition of rhodamine B dissolved in ethanol in concentrations of 0.02mg/mL and 0.10mg/mL, the mechanical properties of non-simplified adhesive systems. 96 crowns of human third molars were transversely sectioned on the oclusal third to remove the enamel and exposure the dentin. The specimens were divided according to the adhesive systems Adper Scotchbond Multi-Purpose (MP) 3-step-etch-andrinse or Clearfil SE Bond (SE) 2-step-self-ecthing: MP-C and SE-C (MP and SE controls); MP-C1 and SE-C1 (MP and SE with 0.02mg/mL rhodamine B); MP-C2 and SE-C2: (MP and SE with 0.10mg/mL rhodamine B). For the ìTBS test, the specimens (n=10) were ground with 320- to 600-grit silicon carbide paper. The dentin was treated according to the instructions of each manufacturer and restored with composite resin FiltekTM Z250. The specimens were stored in artificial saliva (7 days/37oC), and then sectioned to obtain sticks with an average of 0.64 mm2 area and submitted to ìTBS test at a universal testing machine at 0.5 mm/min, which were analyzed immediately after 7 days and 6 months. The mode of fracture of the specimens was analyzed with digital stereomicroscope (x200) and classified as: adhesive, cohesive in dentine, cohesive in resin and mixed. For the SM test, the sectioned crowns (n=6) were flattened with 600-grit silicon carbide paper. The dentin was treated according to the manufacturers instructions for each adhesive system and the specimens were stored in dry condition at 37oC during 48 hours. The SM test was performed with Knoop indenter (Shimadzu HMV-2 hardness tester), at 10x and 25gF of load for 10 seconds. The results were analyzed by two-way analysis of variance tests and the Bonferroni test for multiple comparisons (p<0.05). The analysis regarding time was checked with t-student test. The mean ìTBS and standard deviation (MPa±dp; 7 days / 6 months) were...