Objective: Long term provisionals are needed in cases of implant placement or pulp capping. Materials and methods: Six techniques of PFP reinforcement were investigated and were assigned to different groups (n=10): group(ZP) zirconia Powder, group(SK8) silk thread, group(RC8) size 00 retraction Cord, group(RF8) Resin impregnated glass fiber ribbon, group(KV8) Kevlar 29 cord, group(KV) Kevlar 29 strands incorporated in resin mix, (CL) unenforced Bis-acryl as control group. Seventy Metal Dies were 3D printed having Soft Tissue Gingiva Mask. Using a custom-made silicon Index, 70 PFP were fabricated and were cemented to their corresponding metal dies using zinc polycarboxylate cement. All specimens were thermal cycled for 1000 cycles using order of 20 sec at 55 C and 20 sec at 5 C with 10 sec transport. Fracture resistance test was done using universal testing machine with a load cell of 5 kN. at crosshead speed of 0.5 mm/min. All specimens were loaded to failure. Data were collected, Tabulated and statistically analyzed.
Results: Results showed higher mean values of CL group (780.8  164) followed by RF8 group (614.2  158.2), followed by RC8 group (550.2  339.2), followed by KV8 group (442.1  198.4), followed by KV group (403.9  306), followed by SK8 group (175.9  90.8), and finally ZP group (136.5  135.7). One-Way ANOVA revealed significant difference between tested groups (P= 0.036).
Conclusions: Bis-acryl had better mean fracture resistance values than all other strengthening mechanisms. Bis-acryl did not gain more strength by any of the added materials.