Intrinsic ‘soft-start’ polymerisation shrinkage-kinetics in an acrylate-based resin-composite

Watts, D.C.; Hindi, Alia

doi:10.1016/s0109-5641(99)00012-3

Cited by 156 publications

(80 citation statements)

References 13 publications

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“…This is probably a result of the fact that light-cured resin composites polymerize at a faster rate than chemical-cured resin composites. Although polymerization rate reduction may be achieved by decreasing light intensity [79][80][81][82], low light intensity decreases the degree of conversion that is associated with the mechanical properties of the resin composites, and this may result in poor clinical performance of the restorations [83]. Most of the stress reduction is believed to occur during the first 10 s of light activation [78].…”

Section: The Effect Of Light Curing Modesmentioning

confidence: 99%

Challenges to the clinical placement and evaluation of adhesively-bonded, cervical composite restorations

Kubo

Yokota

et al. 2013

Dental Materials

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Objectives: The incidence of non-carious cervical lesions (NCCLs) has been increasing.The clinical performance of resin composites in NCCLS was previously unsatisfactory due to their non-retentive forms and margins lying on dentin. In order to address this problem, a lot of effort has been put into developing new dentin adhesives and restorative techniques. This article discusses these challenges and the criteria used for evaluating clinical performance as they relate to clinical studies, especially long-term clinical trials. Polymerization contraction, thermal changes and occlusal forces generate debonding stresses at adhesive interfaces.Methods: In laboratory studies, we have investigated how these stresses can be relieved by various restorative techniques and how bond strength and durability can be enhanced. Lesion forms, restorative techniques, adhesives (adhesive strategies, bond strengths, bond durability, and the relationship between enamel and dentin bond strengths) were found to have a complex relationship with microleakage. With regard to some restorative techniques, only several short-term clinical studies were available.

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Section: The Effect Of Light Curing Modesmentioning

confidence: 99%

Challenges to the clinical placement and evaluation of adhesively-bonded, cervical composite restorations

Kubo

Yokota

et al. 2013

Dental Materials

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“…In the studies heretofore, various measures have been taken against enamel micro-cracking, including an increase in the amount of fillers in composite resins, alteration of the irradiator, adjustment of the irradiation time (soft-start curing, step irradiation) [39][40][41][42] , and improvements to the diluent-monomer blending technique.…”

Section: Discussionmentioning

confidence: 99%

Enamel Micro-cracks Produced around Restorations with Flowable Composites

Han

Okamoto

Fukushima

et al. 2005

Dental Materials Journal

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In this study, enamel micro-cracks produced around flowable composite restorations were observed using a stereomicroscope and a scanning confocal laser microscope (SCLM) . The effects of polymerization shrinkage, mobility of composite and polishing period after filling on the incidence of marginal enamel micro-cracks were examined. Enamel microcracks were observed on all of the composite restorations when the restoration was polished immediately after filling. Enamel micro-cracks distributed approximately parallel to the cavity margin and located 0.01-0.3 mm from the restored cavity margin.The occurrence of enamel micro-cracks was higher in conventional hybrid composite restorations than in flowable composites, and when polished 15 minutes after filling (as compared to 24 hours after filling) .

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“…Afterwards, high light intensity is applied to complete the polymerization process and provide proper mechanical properties 10,25 . Since the volumetric contraction of the composite can cause debonding forces and a part of this stress can be compensated during the initial phase of polymerization by the flow of the dental composite 3,4 , the extending in time of the pre-gel phase with stepped irradiation can preserve the marginal integrity of the restoration 10,13,22,26 due to a reduction in the polymerization contraction stress 5,11,24 . The stepped irradiation mode used with incremental filling techniques to restore class I cavities provided bonding strength values similar to those of the control group.…”

Section: Discussionmentioning

confidence: 99%

Effect of irradiation mode and filling technique on resin/dentin bonding strength in class I cavities

et al. 2004

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Factors such as light-curing mode, filling technique and cavity configuration may affect the bonding strength to dentin. This study evaluated the effect of irradiation mode and filling technique on resin/dentin bonding strength on the buccal wall of class I cavities in human teeth. Occlusal enamel was removed to expose a flat dentin surface. Occlusal cavities (4 x 3 x 3 mm) were prepared in dentin. The adhesive Single Bond was applied according to the manufacturer's instructions and TPH Spectrum composite resin was placed using the following: oblique incremental, horizontal incremental or bulk filling techniques. The composite resin was light-cured either by continuous (600 mW/cm² for 40 s) or Soft-Start (250 mW/cm² for 10 s + 600 mW/cm² for 30 s) modes. Specimens of the control group were obtained by bonding the material to the flat exposed buccal wall of the cavity (C-factor = 1). The teeth were stored in water at 37 o C for 24 h and prepared for microtensile testing. Bonded beams of approximately 0.8 mm² were obtained from the buccal wall and tested with a tension of 0.5 mm/min. Results were analyzed by two-way ANOVA, Tukey's test and Dunnett's test (α = 0.05). Incremental placement techniques with both irradiation modes produced higher bonding strength values than the bulk technique (p < 0.05). Bonding strength tested in the cavities had lower values than those obtained in flat dentin surfaces (control group) (p < 0.05), except for incremental fillings using stepped irradiation. Bonding strength to the cavity walls depends on the filling technique and on the irradiation mode of composite resins. DESCRIPTORS: Composite resins; Dentin; Dental cements; Dental enamel. RESUMO:Fatores como o modo de ativação, a técnica restauradora e a configuração cavitária podem afetar a resistência adesiva à dentina. Este estudo avaliou os efeitos dos modos de ativação e das técnicas restauradoras na resistência de união compósito/dentina na parede vestibular de restaurações classe I. O esmalte oclusal dos dentes foi removido para expor uma superfície dentinária planificada. Cavidades oclusais (4 x 3 x 3 mm) foram preparadas em dentina. O adesivo Single Bond foi aplicado de acordo com as instruções do fabricante, e o compósito TPH Spectrum, inserido através de três diferentes técnicas: oblíqua incremental, horizontal incremental ou incremento único. O compósito foi ativado utilizando o método contínuo (600 mW/cm² por 40 s) ou "Soft-Start" (250 mW/cm² por 10 s + 600 mW/cm² por 30 s). O grupo controle foi obtido pela união somente à parede vestibular planificada (fator C = 1). Os dentes foram armazenados por 24 h em água a 37 o C e preparados para o ensaio de microtração (0,5 mm/min). Os espécimes apresentaram na secção transversal uma área de união de aproximadamente 0,8 mm². Os resultados foram analisados pela ANOVA (dois fatores), pelos testes de Tukey e Dunnett (α = 0,05). A técnica incremental seguida da ativação com ambas as formas de fotopolimerização produziu maiores valores de resistência de união que a técnica...

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Intrinsic ‘soft-start’ polymerisation shrinkage-kinetics in an acrylate-based resin-composite

Cited by 156 publications

References 13 publications

Challenges to the clinical placement and evaluation of adhesively-bonded, cervical composite restorations

Challenges to the clinical placement and evaluation of adhesively-bonded, cervical composite restorations

Enamel Micro-cracks Produced around Restorations with Flowable Composites

Effect of irradiation mode and filling technique on resin/dentin bonding strength in class I cavities

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