Properties of dental resins submitted to pH catalysed hydrolysis

Cilli, Renato; Pereira, José Carlos; Prakki, Anuradha

doi:10.1016/j.jdent.2012.09.012

Cited by 63 publications

(68 citation statements)

References 19 publications

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“…There is limited evidence to support significant degradation of dental adhesives at low pH 10, 69 . Results suggest that the degradation of resin-based dental materials occurs at similar rates in water, artificial saliva and in neutral to slightly low pH media 1 .…”

Section: Discussionmentioning

confidence: 99%

“…The rate of this reaction is fast or slow depending on the type of chemical bond, pH, and water uptake 9 . In general, the hydrolysis reaction is expected to be relatively slow at the neutral pH typical of saliva, but excursions in pH caused by foods or cariogenic bacteria may lead to transient acid or base catalysis 10 . Local domains of the polymethacrylate networks may become sufficiently degraded and/or hydrophilic to permit access by esterases, which will accelerate ester bond hydrolysis 11, 12 .…”

Section: Introductionmentioning

confidence: 99%

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Self-strengthening hybrid dental adhesive via visible-light irradiation triple polymerization

Song

et al. 2016

RSC Adv.

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A self-strengthening methacrylate-based dental adhesive system was developed by introducing an epoxy cyclohexyl trimethoxysilane (TS) which contains both epoxy and methoxysilyl functional groups. The experimental formulation, HEMA/BisGMA/TS (22.5/27.5/50, wt%), was polymerized by visible-light. Real-time Fourier transform infrared spectroscopy (FTIR) was used to investigate in situ the free radical polymerization of methacrylate, ring-opening cationic polymerization of epoxy, and photoacid-induced sol-gel reactions. Among the three simultaneous reactions, the reaction rate of the free radical polymerization was the highest and the hydrolysis/condensation rate was the lowest. With 40s-irradiation, the degrees of conversion of the double bond and epoxy groups at 600 s were 73.2±1.2%, 87.9±2.4%, respectively. Hydrolysis of the methoxysilyl group was initially <5%, and increased gradually to about 50% after 48 h dark storage. Photoacids generated through the visible-light-induced reaction were effective in catalyzing both epoxy ring-opening polymerization and methoxysilyl sol-gel reaction. The mechanical properties of copolymers made with TS concentrations from 5 to 35 wt% were obtained using dynamic mechanical analysis (DMA). In wet conditions, the storage moduli at 70 °C and glass transition temperature were significantly higher than that of the control (p<0.05); these properties increased with TS concentration and storage time. The post reaction of hydrolysis/condensation of alkoxysilane could provide persistent strengthening whether in a neutral or acidic environment and these characteristics could lead to enhanced mechanical properties in the oral environment. The cumulative amount of leached species decreased significantly in the TS-containing copolymers. These results provide valuable information for the development of dental adhesives with reduced leaching of methacrylate monomers and enhanced mechanical properties under the wet, oral environment.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self-strengthening hybrid dental adhesive via visible-light irradiation triple polymerization

Song

et al. 2016

RSC Adv.

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“…This deterioration leads to stress and crack growth, thereby resulting in a rapid increase in the amount of water absorbed by the composite material due to silane hydrolysis and degradation 20,36) . Cilli et al 12) found that water uptake by filled specimens is approximately twice that in an unfilled resin. This behavior is attributed to an accumulation of water between the filler/matrix interfaces because of the slow development of superficial flaws related to preexistent corrosive processes.…”

Section: Hydrolytic Degradation Of Silanementioning

confidence: 98%

“…Adding a small amount of titanates can improve bond strength and moisture resistance 11) . Resin composites are widely used in restorative dentistry, and satisfactory clinical performance is largely determined by their resistance to degradation in the oral environment 12,13) . The mechanical properties of resin composites are influenced by their chemical composition and type of environment that they are exposed to.…”

Section: Introductionmentioning

confidence: 99%

Review of titanate coupling agents and their application for dental composite fabrication

Elshereksi

Ghazali

Muchtar

et al. 2017

Dental Materials Journal

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Silane is a dominant coupler that is widely used in dentistry to promote adhesion among the components of dental composites. Silica-based fillers can be easily silanized because of their similarly ordered structure. However, silane is hydrolytically degraded in the aqueous oral environment and inefficiently bonds to non-silica fillers. Thus, the development of hydrolytically stable dental composites is an important objective in the research on dental materials. Titanate coupling agents (TCAs) exhibit satisfactory interfacial bonding, enhanced homogeneous filler dispersion, and improved mechanical properties of the composites. Titanates also provide superior hydrolytic stability in wet environments, which should be considered in fabricating dental composites. The addition of a small amount of titanates can improve the resistance of the composites to moisture. This paper reviews the effects of the instability of silanes in moisture on the performance of dental composites and presents TCAs as alternative couplers to silanes for fabricating dental composites.

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“…The first step in this process is the absorption of water that internally diffuses through the matrix and can lead to softening and degradation, putting some properties such as the roughness of these composites at risk [21]. Despite the high hydrophobic content in the resin matrix of the nanofilled composite tested in this investigation, the presence of TEGDMA makes it sensitive to the absorption of water [1,19].…”

Section: Resultsmentioning

confidence: 94%

Effect of erosion and methods for its control on the surface roughness of composite resin

Cavalcanti

Queiroz

Shibasaki

et al. 2017

Rev. Odonto Ciênc. (Online)

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OBJECTIvE: This study evaluated the surface roughness of a nanofilled composite resin submitted to different degrees of erosion and methods of control. METHODS: 120 cylindrical composite specimens (6×1.5 mm) were randomly divided into four groups, according to the surface protection against the erosive challenge [negative control, topical application of fluoride, glass-ionomer sealant, resin sealant]. After the application of the respective method, specimens were divided into three subgroups (n=10): a) absence of erosive challenge; b) 9 cycles of DES-RE; c) 18 cycles of DES-RE. Surface roughness (Ra, μm) was recorded and statistically analyzed (2-way Anova/Tukey). RESULTS: The glass-ionomer sealant exhibited less rough surfaces under all the conditions. However, the average roughness was significantly higher after 18 DES-RE cycles. CONCLUSION: Despite the potential shown by glass-ionomer sealant, it was concluded that no material prevented an increase in surface roughness of the nanofilled composite after an intense erosive challenge.Key words: Tooth wear; Fluorine compounds; Definitive dental restoration Efeito da erosão e de métodos para seu controle sobre a rugosidade superficial da resina composta RESUMO OBJETIvO: Este estudo avaliou a rugosidade superficial de uma resina composta nanoparticulada submetida a diferentes graus de erosão e a métodos para seu controle. MÉTODOS: 120 corpos de prova cilíndricos (6×1.5 mm) em resina composta foram aleatoriamente divididos em quatro grupos experimentais, de acordo com o método de proteção superficial [controle negativo, aplicação tópica de flúor, selante ionomérico, selante resinoso]. Após a aplicação dos respectivos métodos, os corpos de prova foram divididos em três subgrupos (n=10): a) ausência de exposição à solução simulada de ácido gástrico; b) 9 ciclos de DES-RE; c) 18 ciclos de DES-RE. valores da rugosidade superficial (Ra, μm) foram registrados e analisados estatisticamente (Anova 2-critérios/Tukey). RESULTADOS: O selante ionomérico promoveu superfícies menos rugosas, em todas as condições experimentais testadas. Porém, todas as médias de rugosidade ficaram significativamente mais altas após 18 ciclos de DES-RE. CONCLUSÃO: Apesar do potencial demonstrado pelo selante ionomérico, conclui-se que nenhum material foi capaz de evitar o aumento de rugosidade superficial da resina composta nanoparticuladas após a maior intensidade de desafio erosivo.

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Properties of dental resins submitted to pH catalysed hydrolysis

Abstract: To accelerate composite hydrolysis and produce quick in vitro microstructural damage, alkaline medium appears to be more suitable than acidic medium. Contemporary resin composite properties seem to withstand neutral and acidic oral environments tolerably well.

Cited by 63 publications

References 19 publications

Self-strengthening hybrid dental adhesive via visible-light irradiation triple polymerization

Self-strengthening hybrid dental adhesive via visible-light irradiation triple polymerization

Review of titanate coupling agents and their application for dental composite fabrication

Effect of erosion and methods for its control on the surface roughness of composite resin

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