Treatment date: 10-1-2008

As we progress into the final 7 aligners, critical evaluation is necessary to make changes and alterations in the aligners and in the treatment plan to start developing the final occlusion. The main idea on difficult cases is to get as close to the final occlusion as possible so that major changes do not need to occur in the case refinement aligners.

The lower arch has only the lower left lateral moving over the last 8 aligners. This is the rate limiting tooth in the lower arch, due to the rotation and root movement required. The tooth is tracking well, but not 100% seated in the tray. The attachment is seating in the aligner and there is no adjustment needed with the attachment. However, the contacts are too tight to allow the crown to rotate into proper alignment. This is especially obvious, given that the other teeth are not moving. Accordingly, the distal contact was reduced by 0.10 mm with a rotary single sided disc to clearly open the contact between the lower left lateral and lower left cuspid. In addition, each aligner had a dimple placed on the disto-facial line angle near the gingival margin to provide additional rotational pressure on the tooth.

Further evaluation shows uneven marginal ridges on the lower right first and second molar. This is not likely to be corrected by aligners only. So at this point a decision needs to be made when to correct this with sectional orthodontic appliances. It can be done now, after the full series of initial aligners but before case refinement or it can be done simultaneously with case refinement. I have decided to correct this at this time. I cut away the lower right first and second molar on the right side only and bonded 2 molar brackets with a rectangular niti wire which will upright both molars and align the marginal ridges.

The upper arch alignment is progressing much the same way I have seen in the previous appointments. The upper right lateral and cuspid, as well as the upper left lateral are the teeth that need particular attention. While the contacts around these teeth are very light, I decided to eliminate any doubt that tooth to tooth contact would prevent desired movements. A single-sided air rotor disc created 0.10 mm of space bilaterally on the upper right cuspid, and 0.10 mm between the upper left lateral and cuspid. Dimples were added on the lingual surface near the gingival margin on the mesial marginal ridges to provide additional retention in the aligner and to provide some extra pressure in the direction I want the tooth to move.

I continued the Class III elastic on the right side only, and made adjustments to the aligners to accommodate elastic placement. Previously, I cut grooves into the aligners to hold the elastics. I recently purchased a plier that can make bubbles in the aligners. The bubbles can then be cut to allow elastics to hook into the aligner. See figures 8-12 above for a better understanding of how this was done.