Maxillary adaptation to expansion in the mixed dentition

Area of Science:

• Orthodontics
• Pediatric Dentistry
• Craniofacial Development

Background:

• Early intervention for narrow maxillae is crucial during mixed dentition.
• Orthopedic expansion offers a non-surgical approach to correct maxillary hypoplasia.
• Understanding long-term stability of rapid maxillary expansion (RME) is essential for treatment planning.

Purpose of the Study:

• To evaluate the long-term stability of arch dimension increases achieved through rapid maxillary expansion (RME).
• To assess the maintenance of maxillary arch width following RME in patients during the early mixed dentition.
• To identify factors influencing the retention of expansion gains.

Main Methods:

• A cohort of 162 patients undergoing RME in early mixed dentition was studied.
• Serial dental casts were analyzed to measure changes in arch dimensions pre- and post-expansion.
• Measurements were taken immediately post-expansion and at yearly intervals up to 2.4 years post-expansion.

Main Results:

• An average transpalatal width increase of 5-6 mm was achieved with RME.
• Over 90% of the initial expansion at the first permanent molars was maintained after one year.
• Arch width increases were generally stable, with 80.4% retention at 2.4 years post-expansion.
• Initially narrower arches and more lingually inclined molars showed better expansion retention.

Conclusions:

• Early orthopedic expansion of the maxilla significantly increases arch dimensions.
• The majority of these arch dimension increases are stable by the end of the transitional dentition.
• RME is an effective treatment for maxillary constriction with predictable long-term stability.