Replacing a tooth with an implant involves many visits and the patient feels the dentist keeps changing pieces, so what exactly is the dentist placing? What are the parts that comprise an implanted tooth?
1- First part is called a fixture, often referred to as the implant as well. It is a piece of titanium rod placed into the jaw bone. It represents the tooth root. It comes packed sterile. The top part of the implant is attached to a “fixture mount” which is used only to carry the fixture from its sterile packaging into the jaw bone. The fixture itself must not touch anything, it goes from the package to bone. The fixture comes in various sizes, varying in width and length. Generally speaking, the standard size for a molar tooth is 4.5mm diameter, with 11mm length. For anterior teeth we can use a 3.5mm diameter, 11mm length. Studies show long term success with smaller implants, but if there is room we try to stick to the bigger implants
Once the implant is placed in the jaw, the implant mount is unscrewed from the implant.
2- Now we have a fixture placed in the jaw. The next piece to be used is called gingiva former, or healing cap. It gets screwed into the implant. The function of it, as the name indicates is to force the healing of the gum around the neck of the former, resulting in a tight seal and forming the gums to receive the final crown to mimic natural teeth.
The cap is meant to protrude through the gums. The stitches go around it. The patient goes home with the cap showing through.
3- After the implant has deemed to be ready to receive the final restoration, which is between 6 to 12 weeks, the dentist will unscrew the healing cap.
An impression is needed to represent the implant, teeth, and tissues, in exact relation to each other. A piece called impression coping is screwed into the implant and an impression is taken. This piece comes out half buried in the impression material.
4- A piece that represents the implant is needed. It is called Implant analogue. It gets screwed to the impression coping.
In the meantime, the healing cap is screwed back into the fixture.
The impression is sent to the lab to fabricate the final restoration.
5- The lab pours the impression giving him a plaster model, that represents the mouth and the implant. A rubbery material is also used, it replicates the gum around the implant.
The technician will choose an abutment of adequate dimensions and angulation. This the next piece required. It is called the definite abutment. The lab uses it first. The technician screws it to the model. He might adjust it by trimming.
The lab will fabricate the porcelain crown on tp of the abutment. He sends both the abutment and crown to the dentist.
The dentist first unscrews the healing cap, then screws in the definite abutment, followed by the crown. The crown might be cemented onto the abutment, or screwed onto it.
Articles are written by Dr M Hajarat.