Pong Pongprueksa1, Vesna Miletic2, Henriette Janssens3, Kirsten L Van Landuyt4, Jan De Munck4, Lode Godderis3, Bart Van Meerbeek5. 1. KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium; Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand. 2. KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium; University of Belgrade, School of Dental Medicine, Belgrade, Serbia. 3. Laboratory of Occupational and Environmental Hygiene, Department of Public Health and Primary Care, KU Leuven (University of Leuven), Leuven, Belgium. 4. KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium. 5. KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium. Electronic address: bart.vanmeerbeek@med.kuleuven.be.
Abstract
OBJECTIVE: To evaluate the effect of photo-initiator on the degree of conversion (DC) and elution of Bis-GMA and HEMA for 8 one-step adhesive formulations. METHODS: We used Scotchbond Universal ('SBU-CQ/amine_4.0', 3M ESPE), containing about 2wt% camphorquinone (CQ) and 2wt% ethyl-4-dimethylamino benzoate (EDMAB), an experimental 'SBU-TPO_2.1' version, containing 2.1wt% diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and 6 experimental LUB adhesives (Kuraray Noritake), namely 'LUB-CQ/amine_0.7', 'LUB-CQ/amine_1.4', 'LUB-CQ/amine_4.0', 'LUB-TPO_0.35', 'LUB-TPO_0.7' and 'LUB-TPO_2.0', respectively containing 0.35wt% CQ and 0.35wt% EDMAB, 0.7wt% CQ and 0.7wt% EDMAB, 2.0wt% CQ and 2.0wt% EDMAB, 0.35wt% TPO, 0.7wt% TPO, and 2.0wt% TPO. DC was measured using micro-Raman spectroscopy. Additional specimens were immersed in ethanol for 24h to determine the elution of Bis-GMA and HEMA using HPLC. RESULTS: DC of the respective SBU and LUB adhesives was alike at high photo-initiator concentration. At low concentration, TPO was significantly more efficient than CQ/amine (LUB adhesives only). A statistically significant positive photo-initiator concentration effect on DC was noted for both CQ/amine and TPO (LUB adhesives only). A statistically significant inverse photo-initiator concentration effect on HEMA elution was noted for both the CQ/amine- and TPO-containing LUB adhesives. A significantly strong correlation was found between DC and Bis-GMA elution (R(2)=0.744, p=0.026), and between DC and HEMA elution (R(2)=0.913, p=0.002) for the LUB adhesives. SIGNIFICANCE: The photo-initiator kind and concentration affect DC and the Bis-GMA/HEMA elution. TPO can be used as an alternative photo-initiator for CQ/amine.
OBJECTIVE: To evaluate the effect of photo-initiator on the degree of conversion (DC) and elution of Bis-GMA and HEMA for 8 one-step adhesive formulations. METHODS: We used Scotchbond Universal ('SBU-CQ/amine_4.0', 3M ESPE), containing about 2wt% camphorquinone (CQ) and 2wt% ethyl-4-dimethylamino benzoate (EDMAB), an experimental 'SBU-TPO_2.1' version, containing 2.1wt% diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and 6 experimental LUB adhesives (Kuraray Noritake), namely 'LUB-CQ/amine_0.7', 'LUB-CQ/amine_1.4', 'LUB-CQ/amine_4.0', 'LUB-TPO_0.35', 'LUB-TPO_0.7' and 'LUB-TPO_2.0', respectively containing 0.35wt% CQ and 0.35wt% EDMAB, 0.7wt% CQ and 0.7wt% EDMAB, 2.0wt% CQ and 2.0wt% EDMAB, 0.35wt% TPO, 0.7wt% TPO, and 2.0wt% TPO. DC was measured using micro-Raman spectroscopy. Additional specimens were immersed in ethanol for 24h to determine the elution of Bis-GMA and HEMA using HPLC. RESULTS:DC of the respective SBU and LUB adhesives was alike at high photo-initiator concentration. At low concentration, TPO was significantly more efficient than CQ/amine (LUB adhesives only). A statistically significant positive photo-initiator concentration effect on DC was noted for both CQ/amine and TPO (LUB adhesives only). A statistically significant inverse photo-initiator concentration effect on HEMA elution was noted for both the CQ/amine- and TPO-containing LUB adhesives. A significantly strong correlation was found between DC and Bis-GMA elution (R(2)=0.744, p=0.026), and between DC and HEMA elution (R(2)=0.913, p=0.002) for the LUB adhesives. SIGNIFICANCE: The photo-initiator kind and concentration affect DC and the Bis-GMA/HEMA elution. TPO can be used as an alternative photo-initiator for CQ/amine.