Ultimately you should take into consideration the age of the patient, the treatment area and what we are trying to achieve.
PDO threads are better at repositioning and revitalizing tissue but not for providing lift so would be suited more to younger patients.
PLA threads provide some lifting, but again would be suitable for patients who only require a small amount of tissue lift.
PCA threads provide more lift and are more suitable for patients who require a small to moderate amount of lift. Other factors that have an effect on the desired results are the technique used to insert the threads and the positioning of the threads