Stability of initiation systems in acidic photopolymerizable dental material

作者：Meereis Carine T W; Leal Fernanda B; Ogliari Fabricio A^*

来源：Dental Materials, 2016, 32(7): 889-898.

DOI：10.1016/j.dental.2016.03.016

• Self-adhering flowable composite resin
• Initiator system
• Photoinitiators
• Polymerization
• Shelf life
• Degree of conversion
• Polymerization rate
• Bond strength

Objectives. This study simulated the shelf life to evaluate the stability of initiation systems on acidic photopolymerizable dental material, through an experimental self-adhering flowable composite resin (SACR).
Methods. An SACR model was formulated with monomers Bis-GMA, TEGDMA, acidic monomer (GDMA-P), and inorganic fillers. Initiation system combinations of camphorquinone (CQ), tertiary amine (EDAB), diphenyl phosphine oxide (TPO), phenylbis phosphine oxide (BAPO), and the diphenyliodonium hexafluorophosphate (DPIHFP) were tested. Five SACRs were evaluated, varying the initiation system: SACR(CQ), SACR(CQ+EDAB) SACR(CQ+EDAB+DPIHFP), SACR(BAPO) and SACR(TPO). The SARC were stored at 23 degrees C and, according to shelf life, were evaluated for degree of conversion (DC), polymerization rate (Rp) and microtensile bond strength (mu TBS). The DC was evaluated after 0, 1, 2, 4, 8, 12, 24 and 48 storage weeks of SACRs. Bonding to dentin was performed after 0, 4, 8, 12 and 24 storage weeks of SACRs and tested immediately (24h) and after 6 and 12 months by ii,TBS. Halogen light curing unit (3M ESPE) was used for photoactivation procedures.
Results. SACR(CQ+EDAB+DPIHFP) showed higher Rp. The DC of SACR(CQ+EDAB), SACR(CQ+EDAB+DPIHFP), and SACR(BAPO) were similar (40%) and higher than SACR(TPO) and SACR(CQ) (20 and 10%, respectively), staying stable up to 48 weeks. The SACR(CQ), SACR(CQ+EDAB), and SACR(TPO) had pre-testing failure on mu TBS. The shelf life of SACRs did not affect the mu TBS of the groups that obtained adhesion. Furthermore, the immediate mu TBS (MPa) SACR(CQ+EDAB+DPIHFP) (8.4) was similar to SACR(BAPO) (10.5); however, after 12 months, only SACR(CQ+EDAB+DPIHFP) maintained the mu TBS.
Significance. The choice of a suitable initiation system is crucial to the performance and stability of acidic photopolymeriz able dental material.

• 出版日期2016-7