The average biting force for people with teeth 150 to 250 psi, and for those who clench or grind 1000 psi.    When people no longer had teeth and were using dentures the bite force was reduced to 50 psi.  After using dentures for 15 years bite force was reduced to 5.6 psi and eating can become difficult.  Implants under lower dentures can improve biting force and eating ability.