Skeletal response to maxillary protraction in patients with cleft lip and palate before age 10 years

Abstract

Over the last 15 years, cleft lip and palate (CLP) patients with maxillary deficiency in the care of the Bergen CLP Team have received interceptive orthopedic treatment to correct anterior and posterior crossbites during the deciduous and mixed dentition periods. The present study comprises 72 subjects of various cleft types with anterior crossbite, treated to an acceptable positive overjet by maxillary protraction using a facial mask (Delaire). Lateral cephalograms were taken immediately before and after the active treatment periods. Individuals exhibiting a favorable (fair) skeletal response to the protraction were compared with those who revealed little, (poor) skeletal response. Two cephalometric variables were chosen for the evaluation of the sagittal skeletal treatment changes: (1) the sagittal maxillomandibular change (change of angle ss-n-sm [ANB]); and (2) the forward movement of the maxilla (change of distance NSP-maxp), where maxp (maxillary point) represents the anterior contour of maxilla and NSP is the perpendicular to the nasion-sella-line (NSL) through sella. A numerical change greater than or equal to the value 1.5 (degrees or mm, respectively) was classified as fair versus poor response revealing a change less than 1.5. Fair-response (favorable response) of sagittal maxillomandibular change was found in 63% of the cases (mean increase of angle ANB was 3.3 degrees), more often when protraction started early. The length of maxilla was increased, the skeletal maxilla was moved forward 1.8 mm, the upper dentition advanced 3.6 mm, the occlusal line was clockwise rotated, and the anterior face height was increased. Similarly, fair-response of forward movement of maxilla was found in 44% of the cases (mean increase of distance NSP-maxp was 2.4 mm), more often when protraction was started early and after long treatment duration. The maxillary prognathism increased 1.8 degrees, the angle ANB increased 3 degrees, the length of maxilla increased 1.5 mm, and the upper dentition was advanced 3.7 mm. The anterior face height increased with counterclockwise rotation of the nasal line, whereas the occlusal line was clockwise rotated. A paired fair-response of both skeletal maxillomandibular change and skeletal forward movement of maxilla was found in 35% of the cases. During protraction the mean increase of maxillary prognathism was 2.1 degrees, the maxilla moved forward 3.1 mm, the maxillary dentition advanced 4.3 mm, the maxillary length increased 1.9 mm, the ANB angle increased 3.7 degrees, and the lower anterior facial height increased 3.4 mm.