Effect of micro-osteoperforations (MOPs) on the rate of en masse orthodontic tooth retraction

To evaluate the effect of micro-osteoperforations (MOPs) on the rate of orthodontic tooth movement (OTM) during en masse anterior retraction.

Twenty patients were randomly allocated into experimental and control group of 10 each. In the control group, en masse retraction was performed with sliding mechanics with a coil spring. In the experimental group after alignment and levelling, MOPs were performed mesially and distally to all six anterior teeth in the interdental cortical region on the labial aspect of both arches. MOPs were performed at the beginning of space closure (T₀) and 1 month after beginning of space closure (T₁). En masse retraction was performed with sliding mechanics with a coil spring. Measurements were recorded on digital models made from scanned plaster casts at the beginning of space closure (T₀) and monthly at each follow-up visit for the next 4 months (T₁, T₂, T₃, T₄). The monthly rate of OTM, the overall rate of OTM, and the difference between OTM in the MOP period (T₀–T₂) and post-MOP (T₂–T₄) period in the experimental and control group were evaluated. A visual analogue scale (VAS) was used to evaluate patients’ pain experience.

The overall rate of OTM was significantly greater in the experimental group for both arches in the MOP period (T₀–T₂) and also in the post-MOP period (T₂–T₄) as compared to the control group. Within the experimental group, the rate of OTM in the MOP period was significantly greater than in the post-MOP period, which in turn was greater than that of the control group. The patients reported only mild discomfort for 24 h after performing the MOPs, which then gradually decreased.

The use of MOPs is effective in increasing the rate of en masse tooth retraction in both the maxillary and the mandibular arch. The rate of tooth movement was greater even in the post-MOP period as compared to the control group.