Longitudinal outcomes of bone-anchored maxillary protraction treatment

Bone-anchored maxillary protraction (BAMP) is a well-tolerated treatment for Class III orthopedic effects during adolescence. BAMP aims to improve Class III skeletal relationships with minimal dentoalveolar compensations, in the hope of reducing the need for orthognathic surgery. Our aim was to evaluate the short- and long-term effects of BAMP on measures of tooth and jaw positions and definitive treatment outcomes in patients with Class III malocclusion treated with (+) and without (-) BAMP during adolescence.

Patients treated with BAMP (n = 45) in adolescence were compared with an adolescent Class III control group (n = 39) before comprehensive treatment. Lateral cephalograms were used to quantify skeletal and dental relationships at initial records (T0, before BAMP or growth observation) and at comprehensive initial records (T1) and final comprehensive records (T2). Patients were categorized by their definitive treatment modality: surgical, with 1-jaw and 2-jaw subcategories, or camouflage, with extraction and nonextraction subcategories.

Data indicate that BAMP+ patients had improvements in skeletal measures, including SNA (P = 0.001), ANB (P < 0.0001), and Wits appraisal (P = 0.0001), compared with controls after phase 1 treatment. Between T1 and T2, changes in ANB (P = 0.019), Wits appraisal (P = 0.001), and B-N Vert (P = 0.02) indicate a greater worsening of Class III malocclusion in the BAMP+ group, suggesting additional growth. At the end of comprehensive treatment, BAMP+ patients had a higher ANB (P = 0.026) and A-N Perp (P = 0.012) than controls, whereas controls had greater maxillary incisor protrusion (P = 0.0072) and proclination (P = 0.047). There was no difference in the prevalence or type of orthognathic surgery. Among patients treated with orthodontic camouflage, controls (55.17%) underwent extractions more often than BAMP+ patients (21.05%, P = 0.003).

There is modest improvement in maxillary position associated with BAMP, with a limited effect on dentoalveolar outcomes. BAMP did not influence the comprehensive treatment modality (surgical vs camouflage). However, controls with camouflage were over twice as likely to have extractions compared to BAMP+ patients. Our findings suggest that BAMP may reduce extractions, with a limited effect on the frequency of orthognathic surgery.