IADR 95th

22/75

-22-Fuji II LC1983 Assessment of the Dentin Bond Strength Values of Resin Modified Glass IonomerRestorative Material Using Different In Vitro Test MethodsPoster Presentation11:00 AM–12:15 PM Mar 24, 2017CC, First Floor Authors:AnmarKensara(Presenter)Umm AlQuraUniversityAndre Ritter, University of North CarolinaEdward Swift, University of North CarolinaTerence Donovan, University of North CarolinaLee Boushell, University of North CarolinaChing-Chang Ko, University of North CarolinaJohn Sturdevant, University of North CarolinaJohn Sturdevant, University of North CarolinaAbstract: Objectives: To assess whether the in vitro dentin bond strength values of a resin-modified glass ionomerrestorative material (RMGI) are affected by different in vitro test methods.Methods: Mid-depth occlusaldentin of 36-extracted human third molars free of defects was exposed and finished with wet 600-grit silicon carbide paper for 10s. A commercially-available RMGI (Fuji II LC, GC America) was applied to all specimens according to manufacturer’s instructions, after which specimens were stored in 100% humidity at 37 °C for 24 h. Specimens instructions, after which specimens were stored in 100% humidity at 37 °C for 24 h. Specimens were then randomly divided into three different test groups (n=12): shear bond strength (SBS), microtensilebond strength (µTBS), and four-point bending bond strength (4PBBS). Specimens were loaded to failure using universal testing machines and test-specific parameters: Instronfor SBS and 4PBBS tests, EZ-Test for the µTBStest. The mode of bond failure (adhesive, cohesive or mixed) was qualitatively assessed with optical stereomicroscopy. Data were analyzed using one-way ANOVA and descriptive statistics.Results: There was a statistically significant difference between bond strength values for the different test methods (p<0.05). The mean bond strength values (±SD, in MPa) were 15.7 (±7.1) for SBS, 9.7 (±5.3) for µTBSand 37.3 (±12.8) for 4PBBS. With respect to the mode of (±7.1) for SBS, 9.7 (±5.3) for µTBSand 37.3 (±12.8) for 4PBBS. With respect to the mode of failure, most SBS failures were adhesive in nature (83%), while the majority of µTBSand 4PBBS failures were mixed (69% and 47% respectively). Several µTBSand 4PBBS specimens failed during processing (before testing).Conclusions: The in vitro dentin bond strength values of a resin-modified glass ionomermaterial are greatly affected by the test method. The mode of bond failure is also affected by test method. The SBS test method demonstrated the highest percentage of adhesive failure and proved to be less technique sensitive. The majority of µTBSand 4PBBS failures were mixed. Use of the µTBSand 4PBBS may not be optimal laboratory test methods for comparison of the relative bond and 4PBBS may not be optimal laboratory test methods for comparison of the relative bond strength of RMGI materials to dentin. Use of the SBS test may allow more controlled comparison of the adhesive dentin bond among various RMGI formulations, whether already commercially available or under development.Student PresenterThis abstract is based on research that was funded entirely or partially by an outside source:GC AMERICADisclosure Statement:The submitter must disclose the names of the organizations with which any author have a 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 following is submitted: Umm Al-Qurauniversity: scholarship University of North Carolina at Chapel hill: The school where the research conducted GC AMERICA: MaterialsI have read the IADR policy on licensing.Signed by AnmarKensaraReprinted with permission from the Journal of Dental Research, J Dent Res 96 (Spec Iss A):-22-abstract number 1983, https://iadr2017.zerista.com/event/member/330897, 2017