Effects of Immediate and Delayed Loading on the Outcomes of All-on-4 Treatment: A Prospective Study

The purpose of this study was to compare the outcomes of immediate and delayed rehabilitation of edentulous jaws by means of two straight and two tilted implants after one year of function.
Thirty consecutive patients (16 males, 14 females) were enrolled in this study. Two anterior straight and two posterior tilted implants were placed in each patient. According to the implant insertion torque and the need for bone grafting, implants were loaded immediately (at 72 hours) or delayed (after four months) using a fixed metal resin prosthesis.
One axial implant failed in the delayed group after one year of loading, resulting in cumulative implant survival rate of 99.3%. The mean marginal bone loss was 0.84mm. No significant difference was found between axial and tilted implants in the two groups (P>0.05)
Based on the results, immediate or delayed fabrication of final prosthesis on two tilted and two axial implants did not result in significant differences in survival rates or marginal bone loss.