Long-term stability of miniscrew anchored maxillary molar distalization in Class II treatment

Abstract

Objective: To investigate treatment stability of miniscrew-anchored maxillary distalization in Class II malocclusion.

Materials and methods: This retrospective study included a distalization (n = 19) and a control (n = 19) group; a patient group with minor corrections served the control. Lateral cephalograms of 38 adult patients were taken before (T0), immediately after (T1), and 3-4 years after (T2) treatment. Horizontal and vertical movement and tipping of the maxillary first molars (U6) and central incisors (U1) were measured along with skeletal craniofacial parameters at three time points to compare the two groups regarding the achieved treatment effects and their stability.

Results: Total arch distalization therapy led to 4.2 mm of distal movement of U6 without distal crown tipping (0.6° of axis change) and 3.3° of occlusal plane steepening. Over an average retention period of 42 months, maxillary total arch distalization provided high stability of treatment results, showing the same amount of mesial movement (0.7 mm) as the control group.

Conclusions: In Class II treatment, miniscrew-anchored maxillary total arch distalization can provide stable distal movement of the maxillary first molars and central incisors.

Keywords: Class II malocclusion; Miniscrew anchorage; Molar distalization; Relapse; Stability; Total arch distalization.

Figure 1.

Illustration of intraoral mechanics used for the total arch distalization group.

Figure 2.

Cephalometric (A) linear and (B) angular measurements.

Figure 3.

Schematic drawing of the changes in the distalization (left) and control (right) groups during and after distalization. Dotted, solid, and dashed lines indicate before, immediately after, and approximately 3–4 years after treatment, respectively.