Abstract:
Aim: To evaluate the axial and non-axial retention forces of two different attachment systems (milled titanium bar and locator-milled titanium bar) in implant-supported maxillary overdenture.
Materials and methods: A three dimensional (3D) printed maxillary resin model was constructed from a cone beam computed tomography of an edentulous patient. Four implants were inserted into a maxillary resin model in canines and premolar areas. Five experimental overdentures with metal housings were constructed for each group to be connected to the implants with milled titanium bar attachment (group I) or locator-milled titanium bar (group II) attachment. The Axial retention force (vertical displacement) and non-axial retention forces (anterior, posterior, lateral displacements) were measured in newtons (N) by a universal testing machine at the baseline of the experiment (initial retention T0) and after insertion and removal cyclesT1, T2, T3, till T4 (540 cycles) respectively as a simulation of six months of the overdenture functioning clinically.
Results: The locator- milled titanium bar had a significantly higher axial and non-axial retention forces than the milled titanium bar except in the anterior displacement where milled bar showed significant higher retention forces. Milled titanium bar in vertical displacement and locator- milled titanium bar in posterior displacement had the highest initial retention forces. Lateral retention forces of both attachments showed the lowest retention forces values.
Conclusion: Within this study limitations, the locator-milled titanium bar attachment may provide significantly higher axial, posterior and lateral retention forces compared to milled titanium bar attachment in implant-Supported Maxillary Overdenture.