Clear Idea #4

28 www.acasociety.com | info@acasociety.com not just been brought up to the level of the occlusal plane, but far above that. That is essential. Rebecca was issued with the first of her 26 aligners on 23rd July 2019 when she 27.5 years of age. Treatment proceeded without any problems and before her 28th birthday the upper left second molar had been intruded and was now slightly above the maxillary occlusal plane. No TADs were used. Shortly after, Rebecca’s dentist, Dr. Joshua Jo, placed a crown onto the existing implant replacing tooth 37. This is shown below in Figures 10-13. The last aligners were worn for retention while that work was being completed and then a new scan was done and Vivera retainers ordered. When someone posts before and after records showing a dramatic improvement of the original malocclusion, unless they also give us some idea of how they achieved that outcome, to me it’s just beating your chest, Tarzan like. I have tried not to do that here by detailing the important points, namely: • Be aware of the implications of Newton’s third law. When intruding, if you allow the aligners to lift off adjacent teeth, there will be no intrusive force. Therefore, adjacent attachments for retention are imperative. • Overcorrect. Dr. Begg, a great Australian orthodontic pioneer, stressed the importance of overcorrection of orthodontic tooth movements when using fixed appliances. With aligners, overcorrection is not only necessary to counteract relapse, it is also required to counteract aligner lag. I believe that that too is essential Rebecca is now in routine retention. I realise that this is only one case and you will have to take my word for it that there are not a whole lot of similar cases that I have not shown you because they did not go so well. I have a boutique-sized practice so I do not regularly see cases needing similar intrusion. Nevertheless, I have every confidence that just as I have been able to repeat Dr. Dayan’s intrusion case, so can you. Figure 14 Retention photographs Figure 8 X-ray showing tooth 27 now lifted to the level of the adjacent teeth Figure 9 The intraoral view showing the successful intrusion of tooth 27 at the last aligner stage #26. Figure 10 Intraoral view of the recently placed crown on tooth 37 Figure 12 X-ray showing the crown now placed onto the implant replacing tooth 37 Figure 13 Occlusal view of the new crown over the implant in the tooth 37 area Figure 11 Closer view of the crown on the implant replacing tooth 37