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Updated: Aug 18, 2026
Finite Element Analysis Model for Assessing Expansion Patterns from Surgically Assisted Rapid Palatal Expansion
Published on: October 20, 2023
Skeletal and dental response to rapid maxillary expansion with 2- versus 4-band appliances
Moshe Davidovitch1, Stathis Efstathiou, Ofer Sarne
1Department of Orthodontics, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel. davidom@post.tau.ac.il
Purpose:
Banding a rapid palatal expansion (RPE) appliance to the 2 first molars has been proposed as an equivalent to the conventional 4-band RPE appliance. However, the dentoskeletal response to this treatment has not been evaluated.
Material:
Twenty-eight subjects (aged 8-20 years) who required maxillary expansion were matched by age and randomly assigned to either a 2-band or a 4-band RPE group. Skeletal and dental responses were measured from standardized anteroposterior cephalometric and occlusal radiographs and dental casts before treatment (T1), at the end of expansion (T2), and at 1 year postexpansion (T3).
Results:
At T2, suture expansion was 2.5 times greater and arch perimeter was 6-fold larger in the 4-band than in the 2-band group. Both appliances displayed the typical "V" expansion of the suture and "reverse V" expansion of the dental arch. At T3, remineralization reduced the suture opening by 75%, but 95% to 99% of the dental reaction was maintained. The 2-band group demonstrated a significant inverse age-dependent correlation ( r = -0.795), with treatment failure beyond 12 years of age, whereas the 4-band group was age-independent.
Conclusions:
The greater the skeletal resistance, the smaller the sutural response but the greater the dental response to RPE therapy. Four-band RPE is indicated when severe anterior crowding is accompanied by a tapered arch form, and 2-band RPE is recommended in the mixed dentition when mild crowding occurs with posterior constriction.
