Long-term stability of maxillary protraction therapy in Class III patients with complete unilateral cleft lip and palate

Objectives: This study evaluated the long-term stability of maxillary protraction (MP) in patients with complete unilateral cleft lip and palate (UCLP) and identified factors influencing relapse and long-term outcomes.

Materials and methods: Twenty-three adolescents with UCLP who underwent MP therapy were recalled when craniofacial growth was close to completion. Subjects exhibiting reverse/positive overjets were assigned to unstable/stable groups. Lateral cephalometric measurements were made before treatment (T0), after active treatment (T1), and at the end of the growth spurt (T2).

Results: About 63% of the subjects exhibited positive overjets during follow-up. The unstable group demonstrated higher B-x and Co-Gn distances than the stable group (both P < .05) at T0. More short-term (T0-T1) sagittal advancement of point A (A-y) was evident in the unstable group than in the stable group ( P < .05), but no long-term difference was apparent between the two groups ( P = .481). During the posttreatment period (T1-T2), the SNA angle and maxillary incisor protrusion (U1-SN angle) were considerably lower in the unstable group than in the stable group (both P < .05). Overall, the unstable group exhibited a lower increase in the vertical extent of point A (A-x) than the stable group from T0 to T2 ( P < .05).

Conclusions: In the long term, MP affords favorable maxillary advancement in patients with UCLP. A mandibular excess at T0 and vertical maxillary hypoplasia may contribute to the long-term relapse of a reverse overjet.