Australasian Dentist Magazine May June 2021

Category Australasian Dentist 133 Response 3 This is a fantastic question – and one that I hear so often, that with every patient who has crowding, we go ahead and expand the arch form. This probably is a question that requires a lot more discussion – but all of the literature, and science, actually tells us the expansion of the posterior segments gives us a minimal amount of arch length. By that I mean for 3 mm of posterior expansion, we achieve only 1mm of extra arch length. In other words, for a patient that may have 8mm of crowding, we would require 24mm of posterior expansion to achieve the necessary space to resolve this crowding without any other movements of the anterior teeth. We also know that the most efficient way to gain arch length in a non-extraction approach is to have some inter-canine expansion and some advancement of the upper anterior region – and this is four times more effective than any posterior expansion. My personal view is that most patients who undergo this type of expansion therapy in the mixed dentition , demonstrate an increase in arch length and avoid dental extractions do so not by gaining extra arch width, but more by maintaining the valuable “E” space. Also, this begs the question that when you are expanding the upper arch, and the patient does not have a posterior crossbite – how does one expand the lower arch in a presumably skeletal fashion? In other words, my belief is that we should only use these designated expansion appliances in the upper arch if there is an existing posterior crossbite – otherwise we can change the upper and lower arch form and keep them coordinated purely with our fixed braces and arch wires. Most of these designated expansion devices are advocated by people who have financial interests in dental laboratories, hoping to increase their sales, rather than what’s technically in the best interest of the patient. v v v Q4 Dear Geoff, I am really scared about getting into orthodontics because my local Orthodontist tells me it’s too difficult. What do I have to worry about and how difficult can it really be – when I’m already putting in implants? Dr SJ Northern NSW Response 4 What a fantastic question! There is no doubt that our orthodontic colleagues will tell the general dentist how difficult orthodontics really is and there has been an instruction by the Australian Society of Orthodontists not to teach any conventional orthodontics at the undergraduate level – which I feel is totally wrong, as orthodontics covers the aspect of occlusion, which is one of the foundations of dentistry. I have been teaching orthodontics for many, many years and I can assure you that orthodontics requires the understanding of sound principles, but once these are taught and understood, it is not difficult to perform orthodontic therapy to a very high standard. Like everything in dentistry, one does need to know their limitations and choose cases where they have identified the risks and provided a good treatment plan with good mechano-therapy to obtain their final goals of treatment. Once again, there is no reason to be scared of doing orthodontics – but it is very important to be trained correctly in all aspects of orthodontics and have a good mentor who can help guide you in those cases that may seem difficult at first. This is no different to any other area of dentistry that you would be tackling, including the area of implants that you mentioned. One of the great parts of orthodontics is the fact that the majority of orthodontics is totally reversible unlike implant therapy or endodontics etc, etc, – so provided we stay in this range of reversible orthodontics in the early stages, and then once more knowledge and confidence has been achieved, then you can go to the more irreversible procedures such as extraction treatments. I can assure you that over the years I have been teaching orthodontics to the general dental community – I have had many clients who were initially very scared to do orthodontics, but even after 12 months of their initial training, having gained an understanding of the sound orthodontic principles and risk management they couldn’t believe how simple orthodontics could be and why this has not been taught at a high standard in the past. v v v Q5 Dear Geoff, I remember doing cephalometric analysis at dental school – they made it so difficult that I could never understand what it all meant and it really turned me off even look- ing at orthodontics at all. How important is the cephalometric analysis in your eyes? Dr SW Western Australia Response 5 Once again, a very good question – and like any radiographs in dentistry, they should be designed to confirm our clinical diagnosis and not to make our clinical diagnosis. It’s actually quite funny when you distil down what you are looking for in a cephalometric analysis, most of which should be seen clinically. In other words, there are only four items that you need to address with any cephalometric analysis, and these are: u The sagittal skeletal relationship, i.e. are they Class I, Class II or Class III skeletal relationship. u What is the skeletal vertical – are they a mesio-facial, brachy- facial or dolico-facial tendency. columnists