TY - JOUR
T1 - Influence of photoinitiator type on the rate of polymerization, degree of conversion, hardness and yellowing of dental resin composites
AU - Schneider, Luis Felipe J.
AU - Pfeifer, Carmem S.C.
AU - Consani, Simonides
AU - Prahl, Scott A.
AU - Ferracane, Jack L.
N1 - Funding Information:
This work was done in partial fulfillment of the requirements of the PhD for Luis Felipe Jochims Schneider at the Piracicaba Dental School, State University of Campinas. This work was supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), grant BEX 3667/05-7.
PY - 2008/9
Y1 - 2008/9
N2 - Objectives: To evaluate the degree of conversion (DC), maximum rate of polymerization (Rpmax), Knoop hardness (KHN) and yellowing (b-value) of resin composites formulated with phenylpropanedione (PPD), camphorquinone (CQ), or CQ/PPD at different concentrations. The hypotheses tested were (i) PPD or CQ/PPD would produce less Rpmax and yellowing than CQ alone without affecting DC and KHN, and (ii) Rpmax, DC, and KHN would be directly related to the absorbed power density (PDabs). Methods: CQ/amine, PPD/amine and CQ/PPD/amine were used at low, intermediate and high concentrations in experimental composites. Photoinitiator absorption and halogen-light emission were measured using a spectrophotometer, Rp with differential scanning calorimetry (DSC), DC with DSC and FTIR, KHN with Knoop indentation; and color with a chromameter. The results were analyzed with two-way analysis of variance (ANOVA)/Student-Newman-Keul's test (p < 0.05). Correlation tests were carried out between PDabs and each of DC, Rpmax and KHN. Results: The PDabs increased with photoinitiator concentration and PPD samples had the lowest values. In general, maximum DC was comparable at intermediate concentration, while Rpmax and KHN required higher concentrations. DC was similar for all photoinitiators, but Rpmax was lower with PPD and CQ/PPD. PPD produced the lowest KHN. Yellowing increased with photoinitiator concentration. PPD did not reduce yellowing at intermediate and/or high concentrations, compared to CQ-formulations. PDabs showed significant correlations with DC, Rpmax and KHN. Conclusion: PPD or CQ/PPD reduced Rpmax in experimental composites without affecting the DC. The use of PPD did not reduce yellowing, but reduced KHN. DC, Rpmax and KHN were dependent on PDabs.
AB - Objectives: To evaluate the degree of conversion (DC), maximum rate of polymerization (Rpmax), Knoop hardness (KHN) and yellowing (b-value) of resin composites formulated with phenylpropanedione (PPD), camphorquinone (CQ), or CQ/PPD at different concentrations. The hypotheses tested were (i) PPD or CQ/PPD would produce less Rpmax and yellowing than CQ alone without affecting DC and KHN, and (ii) Rpmax, DC, and KHN would be directly related to the absorbed power density (PDabs). Methods: CQ/amine, PPD/amine and CQ/PPD/amine were used at low, intermediate and high concentrations in experimental composites. Photoinitiator absorption and halogen-light emission were measured using a spectrophotometer, Rp with differential scanning calorimetry (DSC), DC with DSC and FTIR, KHN with Knoop indentation; and color with a chromameter. The results were analyzed with two-way analysis of variance (ANOVA)/Student-Newman-Keul's test (p < 0.05). Correlation tests were carried out between PDabs and each of DC, Rpmax and KHN. Results: The PDabs increased with photoinitiator concentration and PPD samples had the lowest values. In general, maximum DC was comparable at intermediate concentration, while Rpmax and KHN required higher concentrations. DC was similar for all photoinitiators, but Rpmax was lower with PPD and CQ/PPD. PPD produced the lowest KHN. Yellowing increased with photoinitiator concentration. PPD did not reduce yellowing at intermediate and/or high concentrations, compared to CQ-formulations. PDabs showed significant correlations with DC, Rpmax and KHN. Conclusion: PPD or CQ/PPD reduced Rpmax in experimental composites without affecting the DC. The use of PPD did not reduce yellowing, but reduced KHN. DC, Rpmax and KHN were dependent on PDabs.
KW - Camphorquinone
KW - Color
KW - Molar extinction coefficient
KW - Photoinitiators
KW - Photon absorption
KW - Polymerization
KW - Reaction kinetics
KW - Resin composite
UR - http://www.scopus.com/inward/record.url?scp=43449084589&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=43449084589&partnerID=8YFLogxK
U2 - 10.1016/j.dental.2008.01.007
DO - 10.1016/j.dental.2008.01.007
M3 - Article
C2 - 18325583
AN - SCOPUS:43449084589
SN - 0109-5641
VL - 24
SP - 1169
EP - 1177
JO - Dental Materials
JF - Dental Materials
IS - 9
ER -