A study of basal movement with rapid maxillary expansion

Area of Science:

• Orthodontics
• Craniofacial development
• Maxillary growth

Background:

• Rapid maxillary expansion (RME) is a common orthodontic procedure.
• Concerns exist regarding the extent of skeletal expansion beyond the dental arch with RME.
• Investigating the effects on non-tooth-bearing craniofacial structures is crucial.

Purpose of the Study:

• To evaluate the horizontal and posterior expansion of the dental arch via RME.
• To determine if RME can induce dilation of non-tooth-bearing bones, specifically palatine and sphenoidal pterygoid processes.
• To assess the relationship between intermolar and interpterygoid hamular width changes.

Main Methods:

• A cohort of 32 orthodontic patients (12 male, 20 female; aged 8-24 years) underwent RME.
• Intermolar arch widths and interpterygoid hamular widths were measured before and after RME.
• Statistical analysis was performed to determine percentage increases and correlations.

Main Results:

• The mean percentage increase in interhamular widths relative to intermolar widths was 58% (range: 35%-89%).
• A weak positive correlation (r = +0.55) was observed between relative increases in interhamular and intermolar widths.
• A very weak negative correlation (r = -0.33) suggested a slight age-related reduction in expansion, but the effect was minimal.

Conclusions:

• RME effectively expands the maxillary dental arch.
• Evidence suggests RME causes separation of the palatine bones.
• RME also leads to outward splaying of the pterygoid processes of the sphenoid bone.