Distalization pattern of the maxillary arch depending on the number of orthodontic miniscrews

Abstract

Objective: To determine the effects of linear force vector(s) from interradicular miniscrews on the distalization pattern of the maxillary arch in adult Class II patients.

Materials and methods: Twenty-five adult patients with mild to moderate Class II dentition and minimal crowding were collected. Either single (group A, n = 12) or dual (group B, n = 13) miniscrews were inserted on the posterior interradicular area to deliver a distalizing force to the main archwire. The displacement patterns of maxillary incisors and molars were measured and compared.

Results: Significant distalization in the molars and incisors was shown in both groups. Significantly greater distalization and intrusion of the first molar and intrusive displacement of the incisor, together with significant reduction of the mandibular plane, were noted in group B, in contrast to the rotation of the occlusal plane in group A.

Conclusions: Interradicular miniscrews predictably induced total arch distalization, leading to the correction of Class II. Additional miniscrews in the premolar area appear to facilitate intrusion and distalization of the entire arch according to the position of the force vectors.

Figures

Figure 1.

Schematic figure of appliances. (A) Group A. (B) Group B.

Figure 2.

Cephalometric measurements. (A) Linear. (B) Angular measurements.

Figure 3.

Schematized distalization pattern induced by force vector(s) from the miniscrews. (A) Group A indicating rotation of the occlusal plane. (B) Group B indicating intrusive movement of the dentition.

Figure 4.

A case in group B demonstrating the reduction of anterior facial height.