Relationships between conversion, temperature and optical properties during composite photopolymerization

Benjamin Howard, Nicholas D. Wilson, Sheldon M. Newman, Carmem Pfeifer, Jeffrey W. Stansbury

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Optical properties of composite restoratives, both cured and uncured, are of obvious importance in a procedure reliant on photoactivation, since they may affect light transmission and therefore materials conversion upon which mechanical properties and ultimate clinical performance are dependent. The objective of the present study was to evaluate simultaneous, real-time conversion, and the development of the temperature and optical properties. The dimethacrylate resin (Bis-GMA/TEGDMA 70/30 mass%) was prepared at three filler loading (0, 35 or 70 mass%: no fill, low and high fill, respectively) combined with three initiator concentrations (CQ/EDMAB: 0/0, 0.2/0.8 or 1.0/1.6 mass%). Specimens were exposed to either low (50 mWcm2) or high (500 mWcm2) irradiance. Simultaneous conversion (near-IR peak area), temperature (thermocouple) and visible light transmission (UV-vis spectroscopy) measurements were conducted throughout the polymerization process. The refractive index of the resin rises linearly with conversion (r2 = 0.976), producing a refractive index match between resin/filler at approximately 58% conversion in these materials. The percentage increase in light transmission during conversion was greater for increasing filler levels. Higher CQ content led to maximum light transmission at slightly higher levels of conversion (60-65% and 50-55% for the high and low filled materials, respectively). The broad distribution of filler concentrations allows for the clinically relevant generalization that highly filled composites not only jeopardize absolute light transmission, conversion and depth of cure, but also demonstrate the complex interrelationship that exists between materials, processing conditions and the optical properties of dental composites.

Original languageEnglish (US)
Pages (from-to)2053-2059
Number of pages7
JournalActa Biomaterialia
Volume6
Issue number6
DOIs
StatePublished - Jun 2010
Externally publishedYes

Fingerprint

Photopolymerization
Light transmission
Optical properties
Fillers
Light
Temperature
Composite materials
Refractometry
Resins
Refractive index
Bisphenol A-Glycidyl Methacrylate
Dental composites
Thermocouples
Ultraviolet spectroscopy
Polymerization
Spectrum Analysis
Tooth
Mechanical properties
Processing

Keywords

  • Dental composites
  • Depth of cure
  • Optical properties
  • Photopolymerization
  • Reaction kinetics

ASJC Scopus subject areas

  • Biomaterials
  • Biomedical Engineering
  • Biotechnology
  • Biochemistry
  • Molecular Biology

Cite this

Relationships between conversion, temperature and optical properties during composite photopolymerization. / Howard, Benjamin; Wilson, Nicholas D.; Newman, Sheldon M.; Pfeifer, Carmem; Stansbury, Jeffrey W.

In: Acta Biomaterialia, Vol. 6, No. 6, 06.2010, p. 2053-2059.

Research output: Contribution to journalArticle

Howard, Benjamin ; Wilson, Nicholas D. ; Newman, Sheldon M. ; Pfeifer, Carmem ; Stansbury, Jeffrey W. / Relationships between conversion, temperature and optical properties during composite photopolymerization. In: Acta Biomaterialia. 2010 ; Vol. 6, No. 6. pp. 2053-2059.
@article{53ee3458b57f44cdbc6cea55815b79bb,
title = "Relationships between conversion, temperature and optical properties during composite photopolymerization",
abstract = "Optical properties of composite restoratives, both cured and uncured, are of obvious importance in a procedure reliant on photoactivation, since they may affect light transmission and therefore materials conversion upon which mechanical properties and ultimate clinical performance are dependent. The objective of the present study was to evaluate simultaneous, real-time conversion, and the development of the temperature and optical properties. The dimethacrylate resin (Bis-GMA/TEGDMA 70/30 mass{\%}) was prepared at three filler loading (0, 35 or 70 mass{\%}: no fill, low and high fill, respectively) combined with three initiator concentrations (CQ/EDMAB: 0/0, 0.2/0.8 or 1.0/1.6 mass{\%}). Specimens were exposed to either low (50 mWcm2) or high (500 mWcm2) irradiance. Simultaneous conversion (near-IR peak area), temperature (thermocouple) and visible light transmission (UV-vis spectroscopy) measurements were conducted throughout the polymerization process. The refractive index of the resin rises linearly with conversion (r2 = 0.976), producing a refractive index match between resin/filler at approximately 58{\%} conversion in these materials. The percentage increase in light transmission during conversion was greater for increasing filler levels. Higher CQ content led to maximum light transmission at slightly higher levels of conversion (60-65{\%} and 50-55{\%} for the high and low filled materials, respectively). The broad distribution of filler concentrations allows for the clinically relevant generalization that highly filled composites not only jeopardize absolute light transmission, conversion and depth of cure, but also demonstrate the complex interrelationship that exists between materials, processing conditions and the optical properties of dental composites.",
keywords = "Dental composites, Depth of cure, Optical properties, Photopolymerization, Reaction kinetics",
author = "Benjamin Howard and Wilson, {Nicholas D.} and Newman, {Sheldon M.} and Carmem Pfeifer and Stansbury, {Jeffrey W.}",
year = "2010",
month = "6",
doi = "10.1016/j.actbio.2009.11.006",
language = "English (US)",
volume = "6",
pages = "2053--2059",
journal = "Acta Biomaterialia",
issn = "1742-7061",
publisher = "Elsevier BV",
number = "6",

}

TY - JOUR

T1 - Relationships between conversion, temperature and optical properties during composite photopolymerization

AU - Howard, Benjamin

AU - Wilson, Nicholas D.

AU - Newman, Sheldon M.

AU - Pfeifer, Carmem

AU - Stansbury, Jeffrey W.

PY - 2010/6

Y1 - 2010/6

N2 - Optical properties of composite restoratives, both cured and uncured, are of obvious importance in a procedure reliant on photoactivation, since they may affect light transmission and therefore materials conversion upon which mechanical properties and ultimate clinical performance are dependent. The objective of the present study was to evaluate simultaneous, real-time conversion, and the development of the temperature and optical properties. The dimethacrylate resin (Bis-GMA/TEGDMA 70/30 mass%) was prepared at three filler loading (0, 35 or 70 mass%: no fill, low and high fill, respectively) combined with three initiator concentrations (CQ/EDMAB: 0/0, 0.2/0.8 or 1.0/1.6 mass%). Specimens were exposed to either low (50 mWcm2) or high (500 mWcm2) irradiance. Simultaneous conversion (near-IR peak area), temperature (thermocouple) and visible light transmission (UV-vis spectroscopy) measurements were conducted throughout the polymerization process. The refractive index of the resin rises linearly with conversion (r2 = 0.976), producing a refractive index match between resin/filler at approximately 58% conversion in these materials. The percentage increase in light transmission during conversion was greater for increasing filler levels. Higher CQ content led to maximum light transmission at slightly higher levels of conversion (60-65% and 50-55% for the high and low filled materials, respectively). The broad distribution of filler concentrations allows for the clinically relevant generalization that highly filled composites not only jeopardize absolute light transmission, conversion and depth of cure, but also demonstrate the complex interrelationship that exists between materials, processing conditions and the optical properties of dental composites.

AB - Optical properties of composite restoratives, both cured and uncured, are of obvious importance in a procedure reliant on photoactivation, since they may affect light transmission and therefore materials conversion upon which mechanical properties and ultimate clinical performance are dependent. The objective of the present study was to evaluate simultaneous, real-time conversion, and the development of the temperature and optical properties. The dimethacrylate resin (Bis-GMA/TEGDMA 70/30 mass%) was prepared at three filler loading (0, 35 or 70 mass%: no fill, low and high fill, respectively) combined with three initiator concentrations (CQ/EDMAB: 0/0, 0.2/0.8 or 1.0/1.6 mass%). Specimens were exposed to either low (50 mWcm2) or high (500 mWcm2) irradiance. Simultaneous conversion (near-IR peak area), temperature (thermocouple) and visible light transmission (UV-vis spectroscopy) measurements were conducted throughout the polymerization process. The refractive index of the resin rises linearly with conversion (r2 = 0.976), producing a refractive index match between resin/filler at approximately 58% conversion in these materials. The percentage increase in light transmission during conversion was greater for increasing filler levels. Higher CQ content led to maximum light transmission at slightly higher levels of conversion (60-65% and 50-55% for the high and low filled materials, respectively). The broad distribution of filler concentrations allows for the clinically relevant generalization that highly filled composites not only jeopardize absolute light transmission, conversion and depth of cure, but also demonstrate the complex interrelationship that exists between materials, processing conditions and the optical properties of dental composites.

KW - Dental composites

KW - Depth of cure

KW - Optical properties

KW - Photopolymerization

KW - Reaction kinetics

UR - http://www.scopus.com/inward/record.url?scp=77956622677&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77956622677&partnerID=8YFLogxK

U2 - 10.1016/j.actbio.2009.11.006

DO - 10.1016/j.actbio.2009.11.006

M3 - Article

VL - 6

SP - 2053

EP - 2059

JO - Acta Biomaterialia

JF - Acta Biomaterialia

SN - 1742-7061

IS - 6

ER -