Comparison of monomer releasing from Giomers following home and in office chemical tooth bleaching

Abstract

Introduction : During the last years , a major concern exists with respect to the toxicity of resin based materials, and consequently their influence on human health. In a clinical situation, unbound components of resin based materials may diffuse through dentine into the pulp or elute into the oral cavity. Recently a new group of hybrid aesthetic restorative materials known as giomers has been introduced. The aim of this study was to evaluate the monomer elution and the effect of bleaching agents which may result in chemical softening and have implication on the clinical durability of restoration and monomer release. Methods and Materials : 60 samples of giomer , were prepared and polymerized for 40 seconds. Then samples were randomly divided into four groups each of 15. For bleaching two different bleaching products were used; one in office and one at home bleaching agent. Each one group was used as control group and the other was treated with the appropriate bleaching method. Directly after fabrication each sample was stored in 3ml , 37 artificial saliva for 48 hours . After this period, the appropriate treatment took place. The in-office bleaching product (35% carbamide peroxide) was used for 45 min and the home bleaching agent ( 15% carbamide peroxide) was used for 7 days, 8hours in each day ( 56 hours). The samples of the control groups were stored in artificial saliva for the analog time. After bleaching the samples were rinsed under running distilled water using a soft toothbrush. Then, each sample was immediately placed into 3 ml, 37 artificial saliva for 48 hours. The immediate samples and refreshed after 24h , 48h, 7 days were collected for analyses. The saliva samples were analyzed with GC-MS model Saturn 2000. Results : The result of study showed that for control and treatment groups, the released TEGDMA monomer amounts were less than LOD and were not quantifiable in samples. Within the limitations of the present study , the giomer's monomer elution was less than quantifiable level and bleaching did not increase the monomer levels. Conclusion : Therefore , giomers can be used as esthetic materials , and may not have any negative effects on human health due to monomer release caused by inadequate polymerization nor by bleaching