Glossary

An IVJ, or implant verification jig, is an important player in full arch implant reconstructions. This method, when used during the last impression stage, ensures that the final prosthesis fits well onto multi-unit abutments or onto the implants themselves. The implant verification jig offers a solid structure that links the impression copings to make sure the inter-implant relationship is preserved in the final impression. This is especially critical for full-arch cases. With multiple adjacent implants connected securely at the time of the final impression, the implant verification jig allows for a very accurate master cast, a passive fit, and fewer potentially destructive forces that could result in prosthetic failure or bone loss. When impression material flexes, the relative position of two adjacent and unconnected implant transfer copings can move inside the impression material. By using the jig, the periodontist can significantly heighten the accuracy of the master cast that the last restoration will be designed on.

A joint-separating force is any force that has the ability to disengage parts that are joined together by a screw (a screw joint). The opposite of the joint-separating force is called the clamping force. The clamping force must be overcome by the joint-separating force in order for a screw joint to be damaged. This may occur due to incorrect crown height, improper placement of the prosthesis, or even the patient’s chewing habits. A joint-separating force can result in a patient realizing they have a loose implant crown, their implant cap is loose, or even that their implant screw fell out. In the case of a loosened screw, it may be possible to fix the issue without damaging the prosthesis itself. Such problems might be prevented by ensuring the correct torque force is used during the original procedure and by addressing the settling effect before the patient leaves.

The junctional epithelium, sometimes referenced by the initials JE, is the portion of the gingiva or gums that attaches the gums to the enamel, or the surface of the tooth. It’s a thin membrane, about 2-3 mm wide around each tooth, and is only about 15-30 cells thick coronally. Apically, the junctional epithelium tapers to just a single cell. This attachment between the gingiva and the tooth surface is replenished continually throughout a person’s life, about every 4-6 days. Compared to other epithelium in the mouth, which has a regeneration rate of about 6-12 days, the junctional epithelium has a high renewal rate. Junctional epithelium cells have wide intercellular spaces and are non-keratinized, and are responsible for maintaining the seal between the soft tissue of the gums and the tooth. These cells protect jawbone and tooth roots from plaque and bacteria, but in patients with gingivitis or periodontal disease, the seal is weakened.