Labial and Palatal Pressure Changes in Extraction Cases Before and After Maxillary Incisor Retraction: A...

Area of Science:

• Orthodontics
• Dental Biomechanics

Background:

• Orthodontic treatment often involves tooth movement, which can alter the surrounding soft tissue pressures.
• Understanding the interplay between lip pressure, tongue pressure, and incisor position is crucial for successful treatment outcomes.
• The neutral zone concept highlights the balance of forces acting on teeth.

Purpose of the Study:

• To evaluate the impact of incisor retraction following premolar extraction on lip and tongue pressures.
• To compare these pressure changes between patients with Class I and Class II malocclusions.

Main Methods:

• A quasi-experimental study involving 64 patients (32 Class I, 32 Class II malocclusion).
• Lip and tongue pressures were measured using a Flexiforce sensor before and after incisor retraction.
• Statistical analysis included Shapiro-Wilk, Wilcoxon Signed Ranks, and Mann Whitney tests.

Main Results:

• A significant reduction in lip pressure on the labial surface of incisors was observed post-retraction (p ≤0.001).
• Tongue pressure on the palatal side of incisors significantly increased after incisor retraction (p=0.008).
• No statistically significant differences in pressure changes were found between Class I and Class II malocclusion groups.

Conclusions:

• Incisor retraction in orthodontic treatment leads to decreased lip pressure and increased tongue pressure.
• These findings suggest that orthodontic extraction influences the pressure dynamics around the incisors.
• Teeth may not maintain a state of equilibrium at rest following such interventions.