G R E E N W A L L / K AT Z
Orthodontic treatment In this case, the patient’s main concerns where the uneven smile and the shortened upper central incisor teeth. The characteristics of the malocclusion were as follows: • Class I molar and canine occlusion • 5mm overjet • Proclination of the upper and lower incisor teeth • Mild lower anterior crowding • Upper incisor irregularity. After a new patient consultation and a treatment planning discussion where all the options were discussed with the patient, she elected to have an orthodontic assessment to explore the options to move and align the teeth. She was presented with two options, that of fixed braces or aligning treatment. She requested that aligning treatment was undertaken. PVS impressions were sent to Align Technology for conversion into 3D study models using the company’s software. The Clincheck Pro software was used to modify the initial set-up (Figures 10 and 11). When finalised, 20 upper and lower aligners were prescribed, giving a treatment duration of about 10 months (Figures 12 and 13). IPR, totalling 1.2mm in the lower arch and 2.4mm in the upper arch, was prescribed. IPR was necessary to make space to correct the crowding the decrease the incisor protrusion. Treatment proceeded as expected with no complications, or need for refinement. The patient was compliant and wore the aligners 22 hours per day. When treatment was finished and the restorative treatment completed, fixed retainers were bonded upper (palatal) and lower (lingual) on the incisors and canines.
The retention phase Normally, the final aligner acts as the retainer in most cases of Invisalign treatment. Despite extensive research, the various elements leading to relapse of treated malocclusions are not completely understood, which makes retention one of the most challenging aspects of orthodontic treatment (Kuncio et al, 2007). However, in this case, immediately after composite bonding, the upper retainer was cut in the incisal area to allow for the increased incisal length. New impressions were taken after completion of the restorative treatment and new retainers were made to ensure that the occlusion was well maintained. It is essential to stress that patients should wear their Invisalign retainers as prescribed by the
Figure 9: Shades of Aura composite.
orthodontist to ensure stability of the occlusion and correct alignment of the teeth. In a comparative study of the retention of fixed braces versus Invisalign retainers, Kuncio et al (2007) found that, in many cases, aligner treatment can relapse more than fixed braces, and so patients are instructed to continue to wear their retainers for maintenance treatment. However, the total number of patients in each group was 22, which is a very small number and further research is necessary.
Whitening in Invisalign aligners Using the Invisalign aligners as whitening trays has become a viable treatment option for patients. The recommendation is to wait for a month after the first aligners are placed and after the initial discomfort has settled down. The patient applies the whitening gel directly into the aligners. A similar Van Haywood protocol can be adopted, namely to whiten the upper teeth first followed by the lower teeth. The upper teeth whiten quicker and have fewer side effects and so the first stage of whitening is relatively simple. The lower whitening normally takes longer. It is thought that this is due to the wash-out effect of the salivary glands. Due to the rigid nature of the aligner, it seems that whitening may occur quicker than a normal bleaching tray, but this has not been studied significantly. Most aligners do not reach over the gingivae, so the gingivae may be less irritated during whitening. There is no effect of whitening around the orthodontic attachments, and the whitening occurs in a multidirectional way and can whitening around the attachments. Whitening and composite bonding It is essential after completion of home whitening treatment
36 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION VOL.16, NO. 1
