Statement of problem: to enhance the mechanical and biological qualities of heat-cured denture base resins, titanium dioxide nanoparticles (TiO2 NP) are utilized as fillers. Denture base resins' surface roughness is a crucial physical characteristic because roughened denture surfaces are prone to collect bacteria, which can cause oral candidiasis. The aim of this study was to evaluate the surface roughness of implant-retained mandibular overdentures after adding Titanium Dioxide Nanoparticles.

Materials& Methods: Two implants were placed in the canine region of an Epoxy model that simulated an edentulous jaw. After being fastened to the implants bilaterally, the ball and socket abutments were covered by the appropriate metal housing. acrylic resin denture (PMMA) was used to create Group A (the control group), and an acrylic resin treated with salinized titanium dioxide nanoparticles (Tio2 Nps), as the manufacturer's instructions, was used to create Group B. To measure the surface roughness of each denture, use a contact stylus profilometer surface roughness tester. to compare the two groups, the Student's t-test was performed. In all tests, P values under 0.05 are regarded as statistically significant.

Results: The dentures constructed from acrylic resin modified by Salinized Titanium Dioxide (Group B) showed a statistically significant difference than control group (Group A) regarding the surface roughness

 Conclusion: Dentures constructed from acrylic resin modified with Salinized Tio2 Nps had a higher surface roughness than the dentures constructed from acrylic resin only.

Key words: PMMA, Tio2 Nps, surface roughness