This study investigates the effect of the addition of titanium dioxide nanoparticles to denture base materials on their retention compared to that of the unmodified denture base materials.

All patients will be randomly allocated to two equal groups either with the protocol I or II (5 in each group) with an allocation ratio of 1:1 through a computer-generated sequence by a spreadsheet (Excel, Microsoft Office 2010; Microsoft Corp). The group with the protocol I will use the modified dentures with titanium dioxide nanoparticles (TiO2NP) during the first month, followed by no use of the first denture and the use of their old relined dentures instead for 1 month (washout), and then the use of the unmodified dentures for 1 month; the group with the protocol II will use the unmodified dentures during the first month, followed by no use of the first denture and the use of their old relined dentures instead for 1 month (washout), and then the use of the modified dentures TiO2NP for 1 month. Assessment of retention will be done immediately and 1 month after denture insertion.

Inclusion Criteria:

• patients requiring new removable complete dentures, with class I edentulous arches based on the American College of Prosthodontists (ACP) classification15, with an average age of 45-55 years old, with healthy temporomandibular joint, being without systemic disease that could affect the neuromuscular control or salivary flow

Exclusion Criteria:

• Patients with ACP Class II, III, or IV, and xerostomia.

Only the co-author has the IPD. He is responsible to store it in an inaccessible place for anyone.