HEX stands for a hexagonal shaped structure within the implant which serves for the attachment of healing abutment/impression coping.
there are 2 types of HEX:
internal, external.
external HEX is a structure which extends above the implant (& therefore the bone level after the implant has been placed) & serves to attach the healting abutment , impression coping.
internal HEX means serrations on the inner surface of the implant which serves to attach devices like healing abutment.
something like the threads of the screw so that the attachment is flush at the level of bone & not projecting above the bone level as in external HEX.
most of the newer implants are having internal HEX.
also imp. is implant analog which is a replica of implant used by lab people to pour models so as to get a true positive replica of the patients' mouth with implants placed .
so after the implants have been placed in the patient's mouth, healing abutments are placed IMMEDIATELY to avoid soft tissue collapse & after osseointegrations is complete, an impression is taken .
just before impression taking , the healing abutments are removed, replaced immediately by impression coping & the impression is taken.
after that just before pouring the implant analog is attached to the coping in the impression so that once poured you receive an exact replica of the condition in patients' mouth.
hope this clears your doubts.
just google search about HEX, analogue , u will find figures which would make things clear
all the best,👍
