1. ABSTRACT Objectives: To measure flexural strength (FS) and fatigue (FF) of Activa (new RMGIC) compared to RMGI controls (RMGIC), flowable composite-resins (FC) and glass-ionomer cement (GI). Methods: Rectangular samples (2x2x25mm) were made (ISO 4049) according to the manufacturers’ instructions. FS (n=6/gp) and FF (n=11/gp minimum) testing was carried out with a three-point bending test (0.75mm/min, 100 cycles at 0.03Hz, respectively). Flexural stress, load, and displacement were recorded for all tests. FS data were statistically compared (ANOVA, SNK, P<0.05). Statistical data analysis for FF was achieved through the least frequent events method (failures versus non-failures). Results The table below shows test results for FS and FF. Analysis for FS revealed Groups 1-3 were statistically different from Groups 6-12 (P<0.001). Additionally, Group 4 differed from Groups 5-12 (P<0.025). Differences occurred between Group 6 and all Groups (P<0.001). Fatigue statistics demonstrated Groups 1-6 were statistically different from Groups 7-12 (P<0.002). Conclusions: All Activa RMGICs (Groups 1-3) demonstrated comparable flexural strength and fatigue to flowable composites (Groups 4-5) within the present testing limits. Table1. Roughness Data. CONCLUSION All new ACTIVA™ BioACTIVE Products (Groups 1-3) demonstrated comparable mean flexural strength and mean flexural fatigue stresses to flow-able composites (Groups 4-5) within the present testing limits. ACKNOWLEDGEMENTS: Research supported in part by the Pulpdent Corporation and UTHSC College of Dentistry Alumni Endowment Fund. INTRODUCTION Understanding the mechanical performance of various dental materials can help determine a specific patient’s need for treatment. The traditional flow-able composite resins, glass ionomers, and resin modified glass ionomer composites each provide certain benefits for treatment. The new ACTIVA™ BioACTIVE products deliver a new blend of advantages from the traditional materials FC, GI, and RMGIC. 1 Dental materials are often only investigated for flexural strength or static performance within the normal mechanical testing. Although, mechanical fatigue testing can reveal additional data for consideration. Therefore, flexural fatigue was investigated in addition to flexural strength of these new RMGIC’s. To measure the mechanical characteristics, flexural strength and flexural fatigue were characterized and compared using the mean value for each study material similar to ISO 4049. PURPOSE The objective of this study was to evaluate the new RMGIC (ACTIVA™ BioACTIVE Products; BASE/LINER™, CEMENT, and RESTORATIVE™) for flexural strength and flexural fatigue compared to other RMGIC controls, flow-able composite- resins, and glass-ionomer cements. RESULTS Complete flexural strength testing results are located in Table 1 and Figure 2. Statistically analysis revealed the new RMGICs and FCs (Groups 1 thru 5) were significantly different and greater than the control RMGICs and GIs (Groups 7 thru 12) with P<0.001. Furthermore, Geristore (Group 6) was statistically different from all other study Groups, P<0.001. Complete flexural fatigue testing results are located in Table 1 and Figure 3. Statistically analysis demonstrated the new RMGICs and FCs (Groups 1 thru 6) were significantly different and greater than the control RMGICs and GIs (Groups 7 thru 12) with P<0.001. MATERIALS AND METHODS ISO 4049 rectangular samples (2 x 2 x 25 mm) were fabricated in polymer molds according to the manufacturers’ instructions. Samples of each material were stored independently in deionized water for 24 hours at 37°C before testing. Seventeen or more samples were fabricated for each study material. Each material utilized six samples for flexural strength and eleven or more samples for flexural fatigue. Flexural strength and flexural fatigue were evaluated with a three-point bending test fixture on a mechanical testing machine (Instron®; Norwood, MA). Flexural strength was performed at a rate of 0.75 mm/minute until failure. Flexural fatigue testing was achieved by using the frequency of fatigue failures or nonfailure events with the staircase method. 2 Fatigue was executed at 1.8 cycles/minute (or 0.03 Hz) for 100 cycles until completion or failure. Flexural data were compared using an one-way ANOVA with an SNK pairwise comparisons (P<0.05). References: 1 http://www.activabioactive.com/ http://www.activabioactive.com/ 2 Garcia-Godoy F, et. al. Fatigue behavior of dental resin composites: Flexural fatigue in vitro versus 6 years in vivo. J Biomed Mater Res Part B 2012. Groups - Materials Flexural Strength (MPa) Flexural Fatigue (MPa) Group 1: ACTIVA™ BioACTIVE-RESTORATIVE™ (RMGIC)105.4 ± 14.363.7 ± 15.1 Group 2: ACTIVA™ BioACTIVE-BASE/LINER™ (RMGIC)99.8 ± 24.059.0 ± 4.4 Group 3: ACTIVA™ BioACTIVE-CEMENT (RMGIC)97.1 ± 15.859.9 ± 5.9 Group 4: Tetric EvoFlow ® (FC)115.2 ± 15.468.4 ± 26.8 Group 5: Beautifil ® Flow Plus (FC)92.8 ± 18.264.0 ± 11.1 Group 6: Geristore ® (RMGIC)58.8 ± 12.245.5 ± 11.8 Group 7: Fuji Filling ™ LC (RMGIC)22.2 ± 3.87.1 ± 1.9 Group 8: Fuji Lining ™ LC (RMGIC)20.0 ± 17.63.5 ± 0.5 Group 9: Fuji IX ™ GP Extra (GI)28.1 ± 5.03.1 ± 0.5 Group 10: Fuji Triage ® (GI)19.7 ± 4.94.9 ± 3.0 Group 11: Ketac ™ Nano (RMGIC)28.4 ± 10.16.4 ± 1.3 Group 12: Vitrebond ™ Plus (RMGIC)24.0 ± 9.610.2 ± 11.4 Figure 3. Compiled Flexural Fatigue graphical results. Figure 2. Compiled Flexural Strength graphical results. Table 1. Flexural Strength and Flexural Fatigue Data. Figure 1. ACTIVA™ BioACTIVE RESTORATIVE™ and BASE/LINER™.