Effect of proanthocyanidins and photo-initiators on photo-polymerization of a dental adhesive.
OBJECTIVE
To evaluate the effects of proanthocyanidins (PA) and photoinitiator type on the degree of conversion (DC) and polymerization rate (PR) of a model dental adhesive.


METHODS
Three types of photo-initiation systems were introduced into the Bis-GMA/HEMA co-monomer mixture, resulting in four resin formulations including CQ/A (0.5wt% CQ and EDMAB), CQ/A/I-1 (0.5wt% CQ, EDMAB and DPIHP), CQ/A/I-2 (1.0wt% CQ, EDMAB and DPIHP), and TPO (2.1wt% TPO). For each resin formulation, adhesives containing 0%, 2.5%, 5% and 10% of PA with respect to the weight of resin were produced after mixing the resin with various amount of PA/ethanol solution. When light-cured, the RP and DC of each adhesive was determined using ATR-FTIR spectroscopy.


RESULTS
Across and within the initiator groups, the DC followed the general trend of CQ/A<CQ/A/I-1<CQ/A/I-2<TPO and 0-PA>2.5-PA>5-PA>10-PA, respectively. The change of PR with respect to photo-initiation systems and PA content was in a similar but less pronounced pattern.


CONCLUSIONS
PA hampered the polymerization of all adhesives regardless of photoinitiators used. The initiator formulations CQ/A/I-2 and TPO are better fit for PA-containing adhesives, both leading to >65% DC in the presence of 5% PA.


CONCLUSIONS
The inclusion of PA in dental adhesives has been limited by its interference with the light-curing of adhesive resins. This study found photo-initiation formulations that could maintain a satisfactory degree of monomer conversion while a significant amount of PA is incorporated.
University of Missouri-Kansas City, School of Dentistry, Kansas City, MO 64108, USA.
Yi
Y
Liu
Yong
Y
Wang
D001713:Biphenyl Compounds / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D056604:Grape Seed Extract / Q000737:chemistry; D006801:Humans; D008027:Light; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D009861:Onium Compounds / Q000737:chemistry; D010720:Phosphines / Q000737:chemistry; D058567:Photoinitiators, Dental / Q000737:chemistry*; D058105:Polymerization; D044945:Proanthocyanidins / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D027843:Vitis; D062366:para-Aminobenzoates / Q000737:chemistry
C520678:(2,4,6-trimethylbenzoyl) diphenylphosphine oxide; D001713:Biphenyl Compounds; D003432:Cross-Linking Reagents; D056604:Grape Seed Extract; C511402:Grape Seed Proanthocyanidins; D008689:Methacrylates; D009861:Onium Compounds; D010720:Phosphines; D058567:Photoinitiators, Dental; D044945:Proanthocyanidins; D019279:Resin Cements; C523330:ethyl 4-N,N-dimethylaminobenzoate; D062366:para-Aminobenzoates; C031291:diphenyliodonium; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate; D002164:Camphor; C553149:camphorquinone