Copyright © 2026 Authors retain the copyright of this article. This article is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

@article{206212,
        author = {PRASHANT KUMAR and Dr. Sanjayagouda B Patil and Dr. Kiran Kumar HS and Dr. Prajna HD and Dr. K Aishwarya and Dr. Chilakala Ravallika Reddy and Dr. Shreya Anil Kumar Ghattad and Dr. Apoorva B Raj},
        title = {COMPARATIVE EVALUATION OF IMPACT STRENGTH AND SURFACE HARDNESS FOR HEAT CURED POLYMETHYLMETHACRYLATE DENTURE BASE RESIN REINFORCED WITH DIFFERENT PARTICLE SIZE AND CONCENTRATION OF HEXAGONAL BORON NITRIDE PARTICLES: AN INVITRO STUDY},
        journal = {International Journal of Innovative Research in Technology},
        year = {2026},
        volume = {13},
        number = {2},
        pages = {867-879},
        issn = {2349-6002},
        url = {https://ijirt.org/article?manuscript=206212},
        abstract = {Comparative Evaluation of Impact Strength and Surface Hardness for Heat Cured Polymethylmethacrylate Denture Base Resin Reinforced with Different Particle Size and Concentration of Hexagonal Boron Nitride Particles: An Invitro Study”

Background and Objectives:
Polymethyl methacrylate (PMMA) is widely used for denture base fabrication due to its good esthetics, biocompatibility, and ease of processing. However, it exhibits low impact strength and moderate surface hardness, which may lead to denture fracture and wear. Incorporation of hexagonal boron nitride (h-BN) particles has been explored to reinforce PMMA and improve its impact strength and surface hardness, thereby enhancing the durability of denture base resins. The aim of the present study was to compare and evaluate the impact strength and surface hardness of different concentrations and particle sizes of hexagonal boron nitride particles on heat cured polymethyl methacrylate denture base resin.

Materials and Method:
144 samples were prepared with dimensions 65x10x3mm (ISO 1567). These samples were grouped into Group A and B (control groups) containing 8 samples each. Remaining 128 samples were divided into 16 groups according to the concentrations and particle sizes of h-BN. Group N1: 1% wt. of chemically synthesized h-BN nanoparticles, Group N2: 1.5% wt. of chemically synthesized h-BN nanoparticles, Group N3: 3% wt. of chemically synthesized h-BN nanoparticles, Group N4: 5% wt. of chemically synthesized h-BN nanoparticles, Group M1: 1% wt. of chemically synthesized h-BN microparticles, Group M2: 1.5% wt. of chemically synthesized h-BN microparticles, Group M3: 3% wt. of chemically synthesized h-BN microparticles, Group M4: 5% wt. of chemically synthesized h-BN microparticles, for impact strength testing. Group N5: 1% wt. of chemically synthesized h-BN nanoparticles, Group N6: 1.5% wt. of chemically synthesized h-BN nanoparticles, Group N7: 3% wt. of chemically synthesized h-BN nanoparticles, Group N8: 5% wt. of chemically synthesized h-BN nanoparticles, Group M5: 1% wt. of chemically synthesized h-BN microparticles, Group M6: 1.5% wt. of chemically synthesized h-BN microparticles, Group M7: 3% wt. of chemically synthesized h-BN microparticles, Group M8: 5% wt. of chemically synthesized h-BN microparticles, for surface hardness testing. Samples were subjected to impact strength and surface hardness testing. Obtained values were analysed statistically using one-way ANOVA and Tukey’s Post Hoc test.

Results:
The mean impact strength was highest in Group M2 (2.13 kJ/m²), followed by Group N3 (1.32 kJ/m²), Group N2 (1.275 kJ/m²), Group M1 (1.26 kJ/m²), Groups N1 and M3 (1.18 kJ/m²), Groups N4 and A (1.10 kJ/m²), while the lowest value was observed in Group M4 (1.03 kJ/m²).
With respect to surface hardness, the highest mean value was observed in Group N7
(23.19 kgf/mm²), followed by Group M7 (22.64 kgf/mm²), Group M6 (21.59 kgf/mm²),
Group M5 (21.24 kgf/mm²), Group N6 (20.79 kgf/mm²), Group N5 (20.51 kgf/mm²), and Group B (20.33 kgf/mm²). Lower values were noted for Group N8 (19.38 kgf/mm²), with the least surface hardness recorded in Group M 8 (18.99 kgf/mm²).

Conclusion:
The incorporation of chemically synthesized hexagonal boron nitride (h-BN) particles significantly improved the mechanical properties of heat-cured PMMA denture base resin. Although 3 wt% h-BN microparticles demonstrated slightly higher surface hardness, the difference with the other concentrations was not statistically significant. However, 1.5 wt% h-BN microparticles showed a notable leap in impact strength, which is a critical property in preventing denture fracture during functional use or accidental dropping. Therefore, considering the comparable surface hardness and the substantial improvement in impact strength, incorporation of 1.5 wt% h-BN microparticles in PMMA denture base resin may be considered the most favorable concentration for potential clinical application.},
        keywords = {Heat-cured PMMA; Chemically synthesized hexagonal boron nitride; h-BN nanoparticles; h-BN microparticles; Impact strength; Surface hardness.},
        month = {July},
        }