Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 22 0 2025 07 08 5458 5458 Seyed Mostafa Mosavinasab Department of Operative Dentistry, Dental Material Research Center, Dental Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran Kamyar Fathpoor . Department of Operative Dentistry, Dental Material Research Center, Dental Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran Babak Sarrafpoor . School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia Sepidehsaadat Mousavinasab Private practice,Isfahan, Iran Mohamad Hossein Fakour Postgraduate Student, Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran 2024 12 22 2025 03 11 Objectives: The aim of this study is to determine the effect Bioactive Glass (BAG) on dentinal shear bond strength (SBS) of composite resin. Materials and Methods: 120 healthy and intact third molar teeth were selected for this study. Superficial dentin was revealed from 3mm above CEJ by cross sectioning. Then the samples according to the bonding technique and the time of shear bond strength test (after 24 hours, after 3 months of storage in distilled water) were divided into six main groups. Then composite resin applied on exposed dentin surface in 1 mm plastic tubes. The SBS of the samples in each batch was calculated at the initial time and after keeping in distilled water for 3 months with a universal testing machine). For Statistical; analysis Kruskal-Wallis and Mann-Whitney non-parametric tests with Ben Feroni correction were used. The significance level was p<0.05. Results: In the initial time (after 24 hours), effect of adhesive application method (P=0.769), method of adding BAG particles (P=0.951) and the interaction between them (P=0.547) are not significant. During the storage time (3 months of storage in distilled water), effect of adhesive application method is not significant (P=0.417). effect of adding BAG particles is significant (P=0.002) and the interaction effect is not significant (P=0.820). Conclusion: the use of bioactive glass nano particles (45S5) with a low percentage (1%) as a universal dental adhesive filler can increase the strength and maintain the durability of the bond to dentin. This effect is independent of the adhesive application technique. https://fid.tums.ac.ir/index.php/fid/article/view/5458 https://fid.tums.ac.ir/index.php/fid/article/download/5458/2173