Randomized clinical trial comparing control of maxillary anchorage with 2 retraction techniques

Area of Science:

• Orthodontics
• Dental Research
• Clinical Trials

Background:

• Maximum anchorage treatment is crucial for correcting malocclusions like Angle Class I and II.
• Investigating anchorage conservation techniques is vital for treatment efficiency and stability.
• En-masse and 2-step retraction are common methods, but their relative effectiveness in conserving anchorage requires further investigation.

Purpose of the Study:

• To compare the relative effectiveness of en-masse versus 2-step retraction techniques in conserving anchorage during maximum anchorage treatment.
• To evaluate maxillary molar mesial displacement and incisor retraction associated with each technique.

Main Methods:

• A pilot randomized clinical trial involving 64 growing subjects (Angle Class I and II malocclusions) requiring maximum anchorage.
• Subjects were randomized into en-masse retraction (n=32) and 2-step retraction (n=32) groups, stratified by sex and age.
• Lateral cephalograms were analyzed to measure maxillary first molar mesial displacement and incisor retraction.

Main Results:

• Average mesial displacement of the maxillary first molar was slightly less in the en-masse group (-0.36 mm difference), but this was not statistically significant.
• Pooled data (n=63) showed an average mesial displacement of 4.3 ± 2.1 mm.
• Boys and younger adolescents exhibited significantly greater mesial displacement compared to girls and older adolescents, respectively.

Conclusions:

• The study did not find a statistically significant difference in maxillary first molar mesial displacement between en-masse and 2-step retraction techniques.
• Results challenge the clinical belief that 2-step canine retraction is superior to en-masse retraction for preventing anchorage loss.
• Further research with larger sample sizes may be warranted to confirm these findings.