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-8-Fuji IX GP1999 Improved Toughness and Microleakageof an Apatite-Modified Glass IonomerCementPoster Presentation11:00 AM–12:15 PM Mar 24, 2017 CC, First Floor Authors:Authors:AruneeLaiteerapong(Presenter)Faculty of Dentistry, ChulalongkornUniversityYossakitLochaiwatana, Faculty of Dentistry, ChulalongkornUniversityIsao Hirata, Institution of Biomedical & Health Sciences, Basic Life Sciences, Hiroshima UniversityMasayuki Okazaki, Institution of Biomedical & Health Sciences, Basic Life Sciences, Hiroshima UniversitySuchitPoolthong, Faculty of Dentistry, ChulalongkornUniversityAbstract: Objectives: The objectives of this study were to compare the fracture toughness and microleakagebetween Fuji IX GP®(control) and 2.5% Magnesium carbonate apatite (MgCO3Ap) modified Fuji IX GP®(test).Methods: MgCO3Ap was synthesized using a gradient magnesium supply system with an apatite apparatus. The encapsulated cements were mixed with Fuji IX GP®liquid (P/L= 3.6:1) using an amalgamator (4,000 rpm) for 6 s. To determine the fracture toughness, the cements (n=10) were packed into stainless steel molds (2.0x2.5x5.0 mm) under load (10 min), de-molded after were packed into stainless steel molds (2.0x2.5x5.0 mm) under load (10 min), de-molded after 30 min, and transferred to 100% humidity at 37°C for 24 h prior to the three point bending test. To evaluate microleakage, human premolars (n=20) with prepared class V cavities (3.0x3.0x1.0 mm) were filled with their assigned cement per the manufacturer’s instruction. The samples were coated with nail varnish and thermocycledat 5-55°C, 10-5-10 s dwell time, for 500 cycles. The teeth were immersed in methyleneblue for 10 min and sectioned with a diamond saw. The degree of microleakage(0=no, 1=half depth, 2=full depth) at the enamel/dentin-cement interface was evaluated for all specimens (n=40/group) under a stereomicroscope (40X).Results: MgCOAp modified Fuji IX GP®had a significantly higher fracture toughness and less Results: MgCO3Ap modified Fuji IX GP®had a significantly higher fracture toughness and less microleakagein dentin compared with Fuji IX GP®(test=0.60±0.10 MPa.m1/2, 2.5% and control=0.46±0.05 MPa.m1/2, 12.5%).Conclusions: Our results indicate the potential of this novel glass ionomercement with improved fracture toughness and microleakageas a restorative material.Disclosure Statement:The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONEI have read the IADR policy on licensing.Signed by AruneeLaiteerapongReprinted with permission from the Journal of Dental Research, J Dent Res 96 (Spec Iss A):-8-abstract number 1999, https://iadr2017.zerista.com/event/member/330719, 2017