Sunday, 5 September 2010

Long-term stability of surgical-orthodontic open-bite correction, AmJO Sept 2010

On the latest issue of the American Journal there is an interesting article about open bite correction with orthodontics and orthognathic surgery. It is widely known of the difficulty of those cases, mainly due to the relapse that is seen in the long run, even in cases that the final result is optimal, and a good interincisal contact is achieved, along with interdigitation and a "tight" final occlusion.

The material consists of:
  • 39 patients, of 20.8years, mean age.
  • 3 subgroups, of Class I (3 cases only), Class II (20 cases), and Class III (16 cases)
  • Patients had undergone single or double procedure, and pre and post orthodontics.
  • The evaluation and measurements are done on cephalograms, taken before, after treatment and in retention which is in a mean, 8.2years post treatment.
Patients had no facial deformities, were non syndromic, all of them were finished with a positive overbite, and no trauma was present in the area of interest during the retention phase.

  • There was a 64,11% stability of the overall sample
  • Most relapse was present on the Class I-II subgroups with a 47.82% stability percentage.
  • And on the Class III subgroup the stability was the highest with 87.50%
Those are numbers from just a sample of 39 cases, which is not small considering this is an almost 9years long term follow up but the study has some weaknesses:
  • Patients were not treated with the same technic surgically, some were corrected with a single jaw, and others with a double jaw procedure.
  • Surgeon was not the same, and method of surgery not standardized.
However the results show:
  • A statistically significant relapse of those 39 sample open bite cases, after orthodontics and surgery correction. 
  • There is a significant stability on the Class III sub group. 
  • Although in the Class I-II group, half of the cases relapsed.
With results like these it is put into questioning, the protocol with which we approach those difficult open bite cases. We can not be proud if we have results of 50% relapse after 8 years long term follow up.

More research and data published is needed on the long term stability of those cases, a better organized study with one or two surgeons involved, larger groups and standardized orthognathic protocol. Also the musculature should be put to account as well. Myofunctional exercises before and after surgery, as well as during the retention period should be added to the protocol. It is evident that muscles play a role to the high tendency of relapse in those open bite cases, such as tongue thrust, and complex swallowing pattern.

Once again moving from dental to medical is what makes a difference on our treatments outcome and especially on our treatments' stability in the long run.

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