Long-term 3D cast model study: bone-borne vs. tooth-borne surgically assisted rapid maxillary expansion due to secondary variables.

OBJECTIVE

This study aims to compare bone-borne (BB) surgically assisted rapid maxillary expansion (SARME) to tooth-borne (TB) SARME with regard to dentoskeletal effects.

PATIENTS AND METHODS

Measurements were performed on 3D scanned cast models of 34 patients preoperatively and 20.5 +/- 1.34 months post-expansion. Secondary variables were pterygomaxillary disjunction or not; bimaxillary osteotomy or not and patient age.

RESULTS

BB SARME without pterygomaxillary disjunction on patients <20 years led to a symmetric increase in transverse widening; however, simultaneously, to more dental tipping (canines/second molars) and to the biggest overall attachment loss (frontal teeth/premolars), especially, after the performance of bimaxillary osteotomy. TB SARME led to an asymmetric decrease in transverse widening and to more dental tipping (premolars/first molars).

CONCLUSION

In long-term effects, BB SARME led to a symmetric increase in transverse widening; however, at the price of frontal attachment loss, resulting from the initial asymmetric, but bigger, overall transverse widening, the initial major segmental rotation and the necessary orthodontics for tooth arch alignment before and after bimaxillary osteotomy.