Prosthodontics

Process Re-engineering and Complete Dentures

In the Effectiveness and Efficiency I gave an example of how professional time can be lost during the construction of complete dentures when teeth have to be changed after the wax try in stage. Can this loss of time for both dentist and technician as well as the costs of wasted cut-down denture teeth be prevented? Yes it can, if we adopt a process re-engineering approach to this problem.

Traditionally, I, and I think most of my colleagues, were taught to take the shade and the mould at the third appointment, the recording of jaw relations (taking the bite) stage. In fact, in most cases the dentist takes the shade and leaves the technician to decide on the mould. In reality this is unfair to the technician who is unlikely to have seen the patient (customer). It is hardly surprising therefore, that so many dentures have the same appearance with teeth that are far smaller than those of the lost natural dentition, and the inevitable reduced lip support that ensues (Fig 1).

When process re-engineering principles are applied, it is clear that the choice of shade and mould is taking place too late in the stages of denture making. The process can be improved by adopting the following ideas:

1. When a patient books in for new dentures teach your reception and nursing staff to ask the patient, if possible, to bring in to the initial consultation a photograph of themselves when they has they own natural teeth. This will give a discussion point at the consultation, and have the advantage of including your patient in their treatment from the outset. You can discuss the existing denture teeth size and colour and gain an understanding of what result is expected.
2. Together with your patient choose and agree the shade at this visit.
3. Together with your patient choose and agree the mould at this visit.

This is the paradigm shift in denture construction. How might you choose the mould?

1. Obtain from the supplier of your chosen brand of denture teeth a mould chart.This will show the widths and lengths of teeth and the shape of the teeth. If you believe in the Leon Williams method of choosing the mould shape, follow that, although there is no scientific evidence to support this concept. Again you’re your patient, explain your thinking and agree the mould.
2. A better way of displaying moulds is to purchase, if your tooth manufacturer has available, a set of display moulds. This can be shared between colleagues in the practice as a cost saving exercise.
3. A useful starting point for central incisor width determination, and pleasing tooth size, is to take 1/16^th of the interzygomatic width. I use a facebow with the earpieces placed on the side of the face, measure between using a ruler and then divide by 2 and then 8 to give the starting point. Look up this width on the mould chart. If your patient is inclined towards smaller teeth, select a narrower mould, etc.
4. The next stage is another paradigm shift. Order the teeth you have chosen from your supplier or your technician and have them availableto show your patient at the next visit, which will usually be for secondary impressions. Seek agreement on shade and mould now!

If your patient asks for ‘the shade lighter look’, the intact teeth can be returned for exchange. Most suppliers will offer a free exchange service.

5. Show, if necessary, the exchanged teeth to your patient at the next visit, usually the ‘bite’ stage and seek agreement. In most cases you and your technician will be able to proceed in the sure knowledge that the shade and mould are already acceptable, and you have a very good idea of where to place the teeth for the wax try in stage. Only minor adjustments to tooth position should be required, assuming the ‘bite’ is correct, prior to processing in heat cured acrylic resin.

The results that can be achieved are shown (Fig 2). In this case the patient wanted to reproduce her appearance as a twenty something. Her photograph from that time was essential. I hope you will agree that it has been possible to create a more youthful appearance for her and there is definitely more lip support.