Volumetric polymerization shrinkage of contemporary composite resins

Filho, Halim Nagem; Nagem, Haline Drumond; Francisconi, Paulo Afonso Silveira; Franco, Eduardo Batista; Mondelli, R.; Coutinho, Kennedy Queiroz

doi:10.1590/s1678-77572007000500014

Cited by 17 publications

(13 citation statements)

References 11 publications

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“…The calculated shrinkage of the experimental composites fell within the shrinkage observed with current commercial dental composites (1–6%) [ 35 ] and was only slightly greater than that of 2–2.4% observed for Z250 [ 8 , 36 ]. The values were also in agreement with both calculated and experimental results obtained previously for similar formulations [ 20 ].…”

Section: Discussionsupporting

confidence: 68%

Dental Composites with Calcium / Strontium Phosphates and Polylysine

et al. 2016

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PurposeThis study developed light cured dental composites with added monocalcium phosphate monohydrate (MCPM), tristrontium phosphate (TSrP) and antimicrobial polylysine (PLS). The aim was to produce composites that have enhanced water sorption induced expansion, can promote apatite precipitation and release polylysine.Materials and MethodsExperimental composite formulations consisted of light activated dimethacrylate monomers combined with 80 wt% powder. The powder phase contained a dental glass with and without PLS (2.5 wt%) and/or reactive phosphate fillers (15 wt% TSrP and 10 wt% MCPM). The commercial composite, Z250, was used as a control. Monomer conversion and calculated polymerization shrinkage were assessed using FTIR. Subsequent mass or volume changes in water versus simulated body fluid (SBF) were quantified using gravimetric studies. These were used, along with Raman and SEM, to assess apatite precipitation on the composite surface. PLS release was determined using UV spectroscopy. Furthermore, biaxial flexural strengths after 24 hours of SBF immersion were obtained.ResultsMonomer conversion of the composites decreased upon the addition of phosphate fillers (from 76 to 64%) but was always higher than that of Z250 (54%). Phosphate addition increased water sorption induced expansion from 2 to 4% helping to balance the calculated polymerization shrinkage of ~ 3.4%. Phosphate addition promoted apatite precipitation from SBF. Polylysine increased the apatite layer thickness from ~ 10 to 20 μm after 4 weeks. The novel composites showed a burst release of PLS (3.7%) followed by diffusion-controlled release irrespective of phosphate addition. PLS and phosphates decreased strength from 154 MPa on average by 17% and 18%, respectively. All formulations, however, had greater strength than the ISO 4049 requirement of > 80 MPa.ConclusionThe addition of MCPM with TSrP promoted hygroscopic expansion, and apatite formation. These properties are expected to help compensate polymerization shrinkage and help remineralize demineralized dentin. Polylysine can be released from the composites at early time. This may kill residual bacteria.

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Section: Discussionsupporting

confidence: 68%

Dental Composites with Calcium / Strontium Phosphates and Polylysine

et al. 2016

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“…Initiators are activated by light curing and subsequently polymerization progresses as free radicals are released and the double carbon-carbon bond changes to single bonds. Hence, the 0.3-0.4 nm van der Waals molecular distance is replaced by 0.15 nm covalence bonds and a 15% volumetric shrinkage occurs 2,13. Therefore, such a tighter molecular rearrangement with increased density might explain the increased radiopacity when doubling and tripling the curing time.…”

Section: Discussionmentioning

confidence: 99%

“…Volumetric shrinkage is an indicator of the degree of conversion. The smaller the filler particles and the higher the monomer viscosity, the lower the degree of conversion and polymerization shrinkage 1,2…”

Section: Introductionmentioning

confidence: 99%

How does duration of curing affect the radiopacity of dental materials?

Mir

Mir²

2012

Imaging Sci Dent

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PurposeClinicians commonly encounter cases in which it is difficult to determine whether adjacent radiopacities are normal or pathologic. The ideal radiopacity of composite resin is equal to or higher than that of the same thickness of aluminum. We aimed to investigate the possible effects of different curing times on the post-24-hour radiopacity of composite resins on digital radiographs.Materials and MethodsOne mm thick samples of Filtek P60 and Clearfil resin composites were prepared and cured with three regimens of continuous 400 mW/cm2 irradiance for 10, 20 and 30 seconds. Along with a 12-step aluminum step wedge, digital radiographs were captured and the radiopacities were transformed to the equivalent aluminum thicknesses. Data were compared by a general linear model and repeated-measures of ANOVA.ResultsOverall, the calculated equivalent aluminum thicknesses of composite resins were increased significantly by doubling and tripling the curing times (F(2,8)=8.94, p=0.002). Notably, Bonferroni post-hoc tests confirmed that the radiopacity of the cured Filtek P60 was significantly higher at 30 seconds compared with 10 seconds (p=0.04). Although the higher radiopacity was observed by increasing the time, other comparisons showed no statistical significance (p>0.05).ConclusionThese results supported the hypothesis that the radiopacity of resin composites might be related to the duration of light curing. In addition to the current standards for radiopacity of digital images, defining a standard protocol for curing of dental materials should be considered, and it is suggested that they should be added to the current requirements for dental material.

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“…The choice of buildup material depends on the remaining adjacent teeth, occlusion, and the planned definitive restoration. One disadvantage of composite resin is that it is dimensionally unstable . The setting shrinkage during polymerization causes stress on the adhesive bond resulting in cuspal strain with a disruption of the bond, and gap formation that might contribute to long‐term bond failure followed by microleakage and recurrent caries .…”

Section: Principles That Enhance Success When Restoring Endodonticallmentioning

confidence: 99%

Restoration of endodontically treated teeth: contemporary concepts and future perspectives

Baba¹,

Goodacre²

2014

Endodontic Topics

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The concept of using a root for the restoration of a missing crown is not new. Through continuous research, our understanding of the causes of failure has improved. Recent research on endodontically treated teeth has changed contemporary views concerning some principles while consolidating others. Clinical success in restoring endodontically treated teeth depends on our ability to use the latest materials available in conjunction with sound clinical methods. A number of articles have discussed the major factors that play a key role in the long‐term survival of endodontically treated teeth and associated restorations. The purpose of this article is to identify key principles that affect tooth and restoration survival and to present expectations regarding optimal future solutions for the long‐term retention of endodontically treated teeth.

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Volumetric polymerization shrinkage of contemporary composite resins

Cited by 17 publications

References 11 publications

Dental Composites with Calcium / Strontium Phosphates and Polylysine

Dental Composites with Calcium / Strontium Phosphates and Polylysine

How does duration of curing affect the radiopacity of dental materials?

Restoration of endodontically treated teeth: contemporary concepts and future perspectives

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