Thursday, 20 May 2010

Non compliance first molar distalization, AmJO May 2010

The American Journal of Orthodontics of May 2010 includes an article of molar distalization, with an approach similar to a distal jet. The interesting part of this appliance is a stiff guiding segment buccally. Main side effects of the distal jet was mesial rotation, distal tipping, and slight constriction while distalizing the first maxillary molar. As the articles results show on 30 patients, there is a significant minimize of those side effects with this modified approach.

Photos showing the appliance:
Cemented on a 10 year old, on 2nd deciduous and 1st molars

Buccal View

Distalization achieved, although notice sagittaly with the above picture, from 1/2 distal on the canines, patient is on a full distal after the treatment (approximately 50-50 distalization of 1st molar and loss of anchorage to the front..

Following the distalization the front has to be moved backwards, round tripping and increasing chances of resorption.
Photos from AmJO, Noncompliance maxillary molar distalization with the First Class Appliance: A randomized controlled trial, Moschos et all,

As it is concerning distalization, this modified approach, seems better than the conventional distal jet, however another option, would be the pendulum. The springs of the pendulum, provide to the experienced user the possibility of activating on the second order (anti-distal-tipping), the arms like a TPA, thus giving more control. In addition the springs are applying a constant and stable force, on a much less stiffer appliance and thus giving a lesser loss of anchorage.

In the following pictures applying of pendulum with an anterior bite plateau to disocclude:
Pendulum configuration

Initial occlusion right side, on a 14year old, with fully erupted 2nd molars
Cemented pedulum, patient protruding to half distal on the flat anterior bite plateau.
(pendulum was removed, papilla rinsed and re-cemented every appointment, for hygiene reasons)
Full neutral, again protruding from freeing occlusion with the bite plateau (3months pendulum removed same day) notice a minimum loss of anchorage on 1st premolar and canine sagittally when compared with above picture(although 17 was fully erupted and was distalized along with the 16)
Half cusp distal, after initial leveling, and prior high labial canine fully aligned into the arch, post pendulum phase (2 additional months)
Unstable occlusion, patient will easily come forward with class II elastics once on SS wires.

No clinical research, comparing the two approaches, is found, in the literature.

Photos of second case, in treatment, at the OR department of Aarhus, Dimitris Galaktopoulos, DDS.

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