00:00 Introduction
In this video I'm going to give you some useful information for taking a closed tray implant impression.
And if you aren't aware, closed tray impressions are the type where the impression coping comes to a stop inside of the impression tray as opposed to open tray impressions where the impression coping passes through an opening in the tray.
00:28 Closed Tray Impression Copings
Now in order to take the impression you will need a closed tray impression coping which is also known as an indirect transfer. It's important that you only use impression copings that are designed for the closed tray technique to avoid inaccurate impressions.
Closed tray impression copings are designed to be easily removed and reinserted in to the impression after it has set up. Every closed tray coping has some type of index on the body portion that will be captured in the impression. The index could be a single flat side, multiple flat sides, indents or any other design that ensures that the impression coping can be reinserted in to the impression in the correct rotation.
01:10 Coping Orientation
Once you remove the healing abutment, you'll attach the impression coping body to the implant. There are usually multiple different rotations in which the implant coping can be attached. If the implant has a five sided internal interface for example, the impression coping can be placed in one of 5 different rotations. Generally it doesn't matter which rotation you choose, but sometimes a specific rotation might work better. An example of this is if the space between the adjacent teeth is narrow and you have an impression coping with flat sides. Orienting the flat sides to coincide with the contacts will typically be the best option.
01:49 Torque Limit
The impression coping screw can be hand torqued and a torque driver isn't necessary. If you do want to use a torque driver however, you'll just want to make sure you don't torque it past 15 Ncm.
02:02 Cover Access Hole
With the impression coping in place, we recommend that you cover the screwdriver access hole with wax to prevent impression material from flowing in. This is not a necessary step, but it can help to ensure that the impression coping fully seats in to the impression. If wax isn't used and impression material flows in to the driver access hole it'll create a nub inside of the impression that may stop the impression coping from fully seating. When wax is used, it may sometimes stay in the impression when the impression coping is removed, but it's easily remove with an explorer.
02:36 Impression Tray
You're typically going to need to use a single arch tray for implant impressions. Most impression copings are fairly tall and will extend past the occlusal table of the adjacent teeth which would prevent the patient from being able to fully close for a triple tray impression. Even if the impression coping is shorter, using a triple tray can cause an additional problem. And that's because closed tray impression copings rely on the tray itself for their vertical stop. If a triple tray is used, it's possible that the impression coping will tear through the material when it's being reinserted in to the impression.
03:09 Impression Material
It's recommended that you only use medium or heavy body impression material for implant impressions as the greater viscosity will help to maintain positional accuracy. Since you aren't trying to capture a margin, the wash material isn't as necessary. If you do use some light body, keep it to a minimum so that the majority of the impression coping is captured in the heavier material.
03:34 Removing the Tray
Once the impression material has set, you can remove the tray, unscrew the impression coping, and replace the healing abutment. We recommend not placing the impression coping back in to the impression unless an implant replica has been attached to it. If an impression coping is placed back in to the impression without an implant replica, the technician will have to remove the impression coping in order to attach the replica. This can be an issue if only a small portion of the impression coping is sticking out of the impression as it will be difficult to get a good enough hold on the impression coping to pull it out.
04:08 Sending to Lab
Finally, when sending the impression to the lab - be sure to include the impression coping. It's a fairly common occurrence for the coping not to be included with the case which does delay production.
These instructions are relevant to most implant systems including those from Dentsply Astra, BioHorizons, Blue Sky Bio, Hiossen, Implant Direct, Keystone, Mega'Gen, Neodent, Nobel Biocare, Straumann, ZimVie (Zimmer Biomet), and many others.
23 июл 2024
