Photoinitiator content in restorative composites

influence on degree of conversion, reaction kinetics, volumetric shrinkage and polymerization stress

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Purpose: To determine the influence of rate of polymerization, degree of conversion and volumetric shrinkage on stress development by varying the amount of photoinitiators in a model composite. Methods: Volumetric shrinkage (with a mercury dilatometer), degree of conversion, maximum rate of reaction (RP max) (with differential scanning calorimetry) and polymerization stress (with a controlled compliance device) were evaluated. Bis-GMA/TEGDMA (equal mass ratios) were mixed with a tertiary amine (EDMAB) and camphorquinone, respectively, in three concentrations (wt%): high= 0.8/1.6; intermediate= 0.4/0.8 and low= 0.2/0.4. 80 wt% filler was added. Composites were photoactivated (400 mW/cm2 x 40 seconds; radiant exposure=16J/cm 2). A fourth experimental group was included in which the low concentration formulation was exposed for 80 seconds (32 J/cm2). Results: For the same radiant exposure, conversion, RPmax and stress increased with photoinitiator concentration (P<0.001). When the low concentration group exposed to 32 J/cm2 was compared with the high and intermediate groups (exposed to 16 J/cm2), RPmax still increased with the photoinitiator concentration between all levels (P<0.001) but conversion and stress did not vary (P> 0.05). Shrinkage did not vary regardless of the photoinitiator concentration or radiant exposure. For the photoinitiator concentrations used in this study. Polymerization stress was influenced by conversion but not by rate of reaction.

Original languageEnglish (US)
Pages (from-to)206-210
Number of pages5
JournalAmerican Journal of Dentistry
Volume22
Issue number4
StatePublished - Aug 2009

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Conversion Disorder
Polymerization
Bisphenol A-Glycidyl Methacrylate
Differential Scanning Calorimetry
Mercury
Compliance
Amines
Equipment and Supplies

Keywords

  • Different commercially available restorative composites present distinct behavior regarding polymerization stress development
  • Model material
  • Which is a determinant factor on marginal integrity. by using a controlled

ASJC Scopus subject areas

  • Dentistry(all)

Cite this

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title = "Photoinitiator content in restorative composites: influence on degree of conversion, reaction kinetics, volumetric shrinkage and polymerization stress",
abstract = "Purpose: To determine the influence of rate of polymerization, degree of conversion and volumetric shrinkage on stress development by varying the amount of photoinitiators in a model composite. Methods: Volumetric shrinkage (with a mercury dilatometer), degree of conversion, maximum rate of reaction (RP max) (with differential scanning calorimetry) and polymerization stress (with a controlled compliance device) were evaluated. Bis-GMA/TEGDMA (equal mass ratios) were mixed with a tertiary amine (EDMAB) and camphorquinone, respectively, in three concentrations (wt{\%}): high= 0.8/1.6; intermediate= 0.4/0.8 and low= 0.2/0.4. 80 wt{\%} filler was added. Composites were photoactivated (400 mW/cm2 x 40 seconds; radiant exposure=16J/cm 2). A fourth experimental group was included in which the low concentration formulation was exposed for 80 seconds (32 J/cm2). Results: For the same radiant exposure, conversion, RPmax and stress increased with photoinitiator concentration (P<0.001). When the low concentration group exposed to 32 J/cm2 was compared with the high and intermediate groups (exposed to 16 J/cm2), RPmax still increased with the photoinitiator concentration between all levels (P<0.001) but conversion and stress did not vary (P> 0.05). Shrinkage did not vary regardless of the photoinitiator concentration or radiant exposure. For the photoinitiator concentrations used in this study. Polymerization stress was influenced by conversion but not by rate of reaction.",
keywords = "Different commercially available restorative composites present distinct behavior regarding polymerization stress development, Model material, Which is a determinant factor on marginal integrity. by using a controlled",
author = "Carmem Pfeifer and Jack Ferracane and Ronald Sakaguchi and Braga, {Roberto R.}",
year = "2009",
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volume = "22",
pages = "206--210",
journal = "American Journal of Dentistry",
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T1 - Photoinitiator content in restorative composites

T2 - influence on degree of conversion, reaction kinetics, volumetric shrinkage and polymerization stress

AU - Pfeifer, Carmem

AU - Ferracane, Jack

AU - Sakaguchi, Ronald

AU - Braga, Roberto R.

PY - 2009/8

Y1 - 2009/8

N2 - Purpose: To determine the influence of rate of polymerization, degree of conversion and volumetric shrinkage on stress development by varying the amount of photoinitiators in a model composite. Methods: Volumetric shrinkage (with a mercury dilatometer), degree of conversion, maximum rate of reaction (RP max) (with differential scanning calorimetry) and polymerization stress (with a controlled compliance device) were evaluated. Bis-GMA/TEGDMA (equal mass ratios) were mixed with a tertiary amine (EDMAB) and camphorquinone, respectively, in three concentrations (wt%): high= 0.8/1.6; intermediate= 0.4/0.8 and low= 0.2/0.4. 80 wt% filler was added. Composites were photoactivated (400 mW/cm2 x 40 seconds; radiant exposure=16J/cm 2). A fourth experimental group was included in which the low concentration formulation was exposed for 80 seconds (32 J/cm2). Results: For the same radiant exposure, conversion, RPmax and stress increased with photoinitiator concentration (P<0.001). When the low concentration group exposed to 32 J/cm2 was compared with the high and intermediate groups (exposed to 16 J/cm2), RPmax still increased with the photoinitiator concentration between all levels (P<0.001) but conversion and stress did not vary (P> 0.05). Shrinkage did not vary regardless of the photoinitiator concentration or radiant exposure. For the photoinitiator concentrations used in this study. Polymerization stress was influenced by conversion but not by rate of reaction.

AB - Purpose: To determine the influence of rate of polymerization, degree of conversion and volumetric shrinkage on stress development by varying the amount of photoinitiators in a model composite. Methods: Volumetric shrinkage (with a mercury dilatometer), degree of conversion, maximum rate of reaction (RP max) (with differential scanning calorimetry) and polymerization stress (with a controlled compliance device) were evaluated. Bis-GMA/TEGDMA (equal mass ratios) were mixed with a tertiary amine (EDMAB) and camphorquinone, respectively, in three concentrations (wt%): high= 0.8/1.6; intermediate= 0.4/0.8 and low= 0.2/0.4. 80 wt% filler was added. Composites were photoactivated (400 mW/cm2 x 40 seconds; radiant exposure=16J/cm 2). A fourth experimental group was included in which the low concentration formulation was exposed for 80 seconds (32 J/cm2). Results: For the same radiant exposure, conversion, RPmax and stress increased with photoinitiator concentration (P<0.001). When the low concentration group exposed to 32 J/cm2 was compared with the high and intermediate groups (exposed to 16 J/cm2), RPmax still increased with the photoinitiator concentration between all levels (P<0.001) but conversion and stress did not vary (P> 0.05). Shrinkage did not vary regardless of the photoinitiator concentration or radiant exposure. For the photoinitiator concentrations used in this study. Polymerization stress was influenced by conversion but not by rate of reaction.

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