Introduction to impressions
Open tray impressions
Closed tray impressions
Express Abutment
Fitting implant retained prostheses
Managing the occlusion
Glossary of terms

Managing the Occlusion on a Single Implant Retained Crown

There is a lot to say about occlusion and implants so to keep it simple this page will consider the management of occlusion on a single implant retained crown at the fitting stage. As referring dentists take on more demanding cases the page can expand.

Occlusion is considered to be one of the major factors in implant failure so it's important that we get it right. It isn't as hard as it sounds but there are important differences between implants and natural teeth.

• There is no periodontal membrane
• Therefore there is limited proprioception
• Therefore the patient's perception of the forces on the teeth is reduced.

This adds up to a couple of important things:

1. Whilst teeth bounce around on a periodontal membrane, implants don't. Therefore if the bite is adjusted so that the teeth all touch together at the same time this will be absolutely fine on the first light contact. However as the teeth squeeze together the natural teeth will intrude but the implant retained crown will stay exactly where it was. It will therefore be, in effect, high on the bite.

2. The limited proprioception of implants is thought to come from deformation of the bone and the receptors in the periosteum. This is nowhere near as sensitive as the proprioception from the periodontal membrane. Therefore the patient can put high forces on the implant without knowing about it. Because of this limited sensory feedback, the patient can inadvertently place very damaging forces on the implant.

All this leads us to the guidelines below:


1. Light load under heavy clenching
This is how you avoid the problem of natural teeth that intrude and implants that don't. Take your articulating paper. Use the thin stuff. Big fat horseshoe articulating paper is no good for this. Start with the patient tapping lightly and adjust the implant retained crown until there is even contact. Now ask the patient to squeeze together. If the implant retained crown was in even contact before, it will now be high. Keep adjusting it until you have only the lightest contact when the patient is clenching hard. At this point you will have heavy marks from the articulating paper on the adjacent teeth and just a light touch on the implant retained crown. There you have it, light load under heavy clenching.

2. Occlusal force directed down the long axis of the implant
This results from good planning and begins with placement of the implant at the surgery stage. Your technician will also play a vital role in contouring his restorations so that forces are directed as axially as possible. When it comes to adjustment at the fitting stage be aware of this and try to maintain axially directed contacts as far as you can.

3. Light or no occlusal contact in excursions
Take a different coloured articulating paper and ask the patient to rub the teeth from side to side and backwards and forwards. The patient will need to squeeze hard whilst doing this for the same reasons as before. Now take your first colour of articulating paper and ask the patient to squeeze hard straight down onto the teeth again. Now what you should see is the original occlusal contact in one colour and the excursions in another. Keep adjusting the excursions on the implant retained crown until they've disappeared or at least until they are very light.

By adjusting the implant retained crown this way we use the adjacent teeth to provide the proprioception that is necessary to avoid damaging forces to the implant.

Where the occlusal adjustment is likely to be more complex we will discuss this with you before embarking on treatment. Please ring us for advice if you are not sure.

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