EFFECT OF TWO DIFFERENT RESTORATIVE MATERIALS ON STRESS DISTRIBUTION ON ALL-ON-FOUR IMPLANT RETAINED RESTORATIONS

Purpose: The purpose of this in vitro study was to evaluate the effect of restorative material either zirconia or BioHPP on stress distribution affecting periimplant supporting structures.
Materials and methods: Four implants were installed using a surveyor in a maxillary model. Scan bodies were used to scan implant fixture position using identica hybrid desktop scanner then Exocad software was used to design a cutback implant retained restoration. VHF 5 axis milling machine was used for manufacturing of zirconia & bioHPP restoration from the same STL design, veneering was then performed by feldspathic porcelain & composite respectively. Strain gauge was installed 1mm distal to implant fixture. Universal testing machine was used to apply both axial & off axial loads 100 N & microstrains were recorded to test amount of developed strain around implant.
Results: The results of independent t test showed that there was no statistically significant effect between bioHPP and Zirconia groups under axial loading (p= 0.064) and off axial loading (p=0.11)
Conclusions: Based on the present in vitro results, the change in restoration material did not affect the stress distribution in implants and peripheral bone under axial & off axial loads.