IADR Abstract Archives
Optimizing photo-initiator system of new fluoride-releasing acrylic orthodontic adhesive
Objectives: White spot lesions are a common complication with orthodontic treatment. We are developing a photo-polymerizing fluoride-releasing orthodontic adhesive. This study aims to investigate the effect of different initiator systems on degree of conversion (DoC) of the developed material.
Methods: Sodium fluoride at 10wt% was added to 90wt% polymethylmethacrylate powder and mixed at a powder:liquid ratio of 2:1 with liquid 2-hydroxyethylemethacrylate and methylmethacrylate (40wt%:60wt%), alongside two concentrations of acetone (A-0wt% and 10wt%). Four groups of resin were prepared with varied photo-initiator systems: (1) 1wt% camphorquinone and 1wt% N,N-dimethylaminoethylmethacrylate (DMAEMA); (2) 1wt% camphorquinone and 1wt% Ethyl 4-(dimethyl-amino) benzoate (EDAB) activator; (3) 1wt% diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide (Lucirin TPO) and (4) 1.5wt% Lucirin TPO (table 1). FTIR was used to measure DoC for all the materials at 10, 20, 30, 40 and 80s of light curing using Bluephase®20i at 1130mW/cm2.
Results: The DoC of group CQ/DMAEMA at 10%Acetone are higher than CQ/EDAB at 30, 40 and 80s (p<0.05). The DC of all groups with Lucirin TPO was higher than groups with CQ initiator system (p<0.05, one-way ANOVA).
Conclusions: Lucirin TPO is an effective photo-initiator system which results in higher and faster polymerisation than the CQ system.
Methods: Sodium fluoride at 10wt% was added to 90wt% polymethylmethacrylate powder and mixed at a powder:liquid ratio of 2:1 with liquid 2-hydroxyethylemethacrylate and methylmethacrylate (40wt%:60wt%), alongside two concentrations of acetone (A-0wt% and 10wt%). Four groups of resin were prepared with varied photo-initiator systems: (1) 1wt% camphorquinone and 1wt% N,N-dimethylaminoethylmethacrylate (DMAEMA); (2) 1wt% camphorquinone and 1wt% Ethyl 4-(dimethyl-amino) benzoate (EDAB) activator; (3) 1wt% diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide (Lucirin TPO) and (4) 1.5wt% Lucirin TPO (table 1). FTIR was used to measure DoC for all the materials at 10, 20, 30, 40 and 80s of light curing using Bluephase®20i at 1130mW/cm2.
Results: The DoC of group CQ/DMAEMA at 10%Acetone are higher than CQ/EDAB at 30, 40 and 80s (p<0.05). The DC of all groups with Lucirin TPO was higher than groups with CQ initiator system (p<0.05, one-way ANOVA).
Conclusions: Lucirin TPO is an effective photo-initiator system which results in higher and faster polymerisation than the CQ system.
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