tips and tricks

 Recently I attended an anterior waxup course and photography course run by Szabi Hant, a technician from Perth who works with Tony Rontondo, a Brisbane based prosthodontist. Overall, I could tell he was a very knowledgeable and skilled technician but not the best lecturer and demonstrator. Over the two days, this manifested in different ways.  The hands on component of the waxup course were him waxing up 3 anterior teeth on a stone model projected in a screen for the class. I think there was a lot of muscle memory involved and he proceeded through the waxup with some explanation as to what he was doing and important things to look out for but not much explanation in terms of finer aspects. For example, I would have been good to get his take on how to handle and manipulate wax and some more theory on instrument choices and wax types. To be fair, he made a valid point that the hands on component was the most important aspect of the course and the bulk of the time was spent on t...

Ensure the teeth are relatively clean of food and plaque prior to impressions. I can't count the number of times I have taken an impression and bits of interproximal food come out with the impression. Usually in perio patients and usually in posterior teeth. Really heavy plaque will affect your surface detail capture and food will affect your accuracy and look gross for the lab an on the model. It will also affect your impression disinfection.  If there is really heavy plaque, give the teeth a good prophy or teach the patient how to use a toothbrush and reschedule. If the patient has recently eaten, give their mouth a good rinse and floss. When I haven't done this and there is food that comes out with the first impression, usually the second impression goes well.

Occasionally I have issues with bite registration getting stuck in tooth undercuts in the mouth and being difficult to remove. This is not a major issue as the bite registration usually flexes out or breaks at the point where it is stuck. This can make the bite registration more difficult to handle in the lab stage but is not a big problem. This is becoming especially common as I have switched to a more rigid bite registration material which makes it easier to trim and introduces less inaccuracy during mounting as the material won't deform as much under compression. Watch out for situations where there are multiple non adjacent missing teeth especially with kennedy class 3 situations with bounded saddles. Also kennedy class 4s can be an issue  with especially canines having deep mesial undercuts. Every denture aspect is improved in kennedy class 3s but the bite registration is made more difficult. In class 1 and 2 situations will flex out but 3 and 4 will get locked in. Try not to ...

Class 1 occlusions are the ideal occlusions discussed in the textbooks but they aren't always present. In fact, the majority of people in the community will be class 2. The occlusal contacts represented as dots and lines in the diagram of the previous part is based on a class 1 occlusion. Class 2 and class 3 occlusions will show different relationships and achieving a class 1 occlusion post treatment is not always possible or desirable when considering the goals of the patient. It is important to know why we do what we do and why the goals of treatment is what they are so that we can bend the rules as needed. The main change with Class 2 and 3 occlusions is the anterior guidance component of the occlusion. distribution of occlusal contacts is possible in any occlusion as the reason why we aim to do this is to reduce the non axial loads through teeth when the muscles are at their highest force. The position of these contacts may change with different positions on the occlusal sur...

Occlusion can be studied to try and improve success or reduce failures. Occlusion isn't a goal but it is a tool that we can use to achieve our goal. Everything fails if given enough time but we are aiming to slow the progress of this down so that the failure occurs as far away as possible. Patients need to understand this risk before agreeing to any treatment. Dental materials excepting fracture from trauma tend to break after repeated cyclic fatigue. The management of occlusion aims to reduce the force on teeth and restorations to reduce cyclic fatigue failure. This aim is independent of the materials used. Be it LiSi, zirconia, gold, base metal, composite, amalgam, enamel or dentine they will all fail if loaded enough for enough time. Materials that claim extrordinary strength such as some zirconias have the trade off of being very brittle. On the other hand, materials that are softer such as gold will burnish under high load, adapt to the conditions and therefore is less likel...