Australasian Dentist Issue 89

Category 122 AustrAlAsiAn Dentist Q1 Dear Geoff, i have many patients who have completed orthodontic treatment in specialist practices and there seems to be a discrepancy as to how long a patient should be wearing their retainer and they are also advised to have their wisdom teeth removed post treatment. Can you please advise what your thoughts are? Dr JP, sydney, new south Wales Response 1 Dear JP, there is obviously a lot of controversy with regards to the area of retention in orthodontics. unfortunately, there is no great science behind what we do – from all scientific studies in this area of retention, the basic research coming from seattle by Dr little would demonstrate that relapse would occur in all types of patients treated orthodontically – whether it be an extraction case, a non-extraction case, distallisation, an edge wise case or even a begg case. in other words, teeth always have a tendency to want to move back to where they came from originally – and there are many different theories that relate to the reasons for relapse. One of the classical theories from the 1950’s, was the fact that it was impossible to expand the lower inter-canine distance and achieve stability – hence a lot of orthodontists would be placing a permanent bonded wire on the lower anterior teeth to try and maintain the lower inter-canine dimension. i believe there is a balancing act between retention and patient management. in our practice we place a lower lingual bonded retainer which, as far as we are concerned, should be in place for the rest of one’s life, and in the upper arch we usually place a removable essix retainer and suggest that this is worn full time for at least 12 months, then a further 12 month on a night time basis, and then from there on indefinitely 2-3 times a week at night. From a biological point of view – we know that bone constantly turns over throughout life, as seen with elderly patients who undergo osteoporosis, and as teeth are held in bone, there obviously will be some shifting of teeth as part of those bony changes. Hence, the requirement for long term retention to counteract these (ageing) changes that occur with just normal bone turnover. there are many people who believe that wisdom teeth will aggravate the situation, especially with lower anterior crowding, anecdotally this may be true, however all scientific research has shown that patients who are congenitally missing their wisdom teeth will also have future mandibular crowding, and hence in the orthodontic community there is some debate as to whether wisdom teeth are an aetiological factor in future latent mandibular crowding. Overall though, most Orthodontists would prefer to have wisdom teeth removed if they are mesio-angularly positioned and possibly could cause some mesial force system to the dentition. v v v Q2 Dear Geoff, i am asked by many parents as to what age should a child start orthodontic treatment. i hear that there are a lot of general dentists out there performing orthodontics on a child as young as four or five and then there are other people who prefer just to wait until all the permanent teeth have fully erupted. What is the general consensus among Orthodontists and what is your view as to the best age to commence orthodontics for a child? Dr sW, north Queensland Response 2 Dear sW, What a controversial question you ask! As once again i wish there was an exact science that could answer this very involved question. Firstly, my personal opinion is that there is an exceptional amount of orthodontic overtreatment with the young patient. in fact, i remember very well, a lecture when i was at the university of Pennsylvania, with one of my wonderful mentors, Dr Henry O’Hearn. He presented case after case with slides and asked each of the students, “How did i treat this particular case?”. We, as students, talked about palatal expansion, serial extraction, early orthodontic intervention etc, etc, and for one and a half hours Henry O’Hearn presented case after case after case and did not say one word. At the end of his presentation he packed up his slide carousels and started walking out – and at that point we asked Henry, “so how did you treat these patients?”. Henry just turned around and with a very wry smile said, “i just took photographs”. this was one of the great learning exercises of my time – as it demonstrated a lot of cases could be treated with letting nature take its own course. this does not mean to imply that children should not undergo early orthodontic therapy – and there are definitely cases which should have early treatment, and when i teach this in our OrthoeD program, one of my important questions is, “Will early orthodontic treatment for this patient significantly reduce the severity of the malocclusion with the possibility of eliminating it?”. if the answer to this question is “nO”– early orthodontic treatment is not warranted. in other words, if this patient was going to have to undergo full braces anyway at the age of 12, and i could have treated them with a non-extraction approach, why put Orthodontic Clinicians’ Corner Welcome to this month’s edition of Orthodontic Clinician’s Corner, where Dr Geoff Hall will answer orthodontic questions asked by general dentists. If you have an orthodontic question you would like answered, forward your question to geoff@orthoed.com.au ColuMnIsts By Dr Geoff Hall Dr Geoff Hall