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.

Class II correction by maxillary en masse distalization using a completely customized lingual appliance and a novel mini-screw anchorage concept – preliminary results

“…A Class I occlusal relationship defines the gold standard when assessing the outcome of an orthodontic treatment, as described by various scores [ 27 – 29 ]. Therefore, we did not use radiographic landmarks to evaluate molar distalization, as has frequently been proposed by various authors [ 24 , 30 – 43 ]. The measurement method, which was introduced previously, is relatively simple and can be applied to each lateral segment, separately, which is of major importance particularly in asymmetric Class II cases [ 7 , 44 ].…”

Factors associated with the maxillary third molar position after total arch distalization using a modified C‐palatal plate in adolescents

“…Traditionally, several devices such as headgear and pendulum appliances have been used to distalize maxillary molars during nonextraction treatment, [1][2][3] but some studies achieved successful distalization using buccal miniscrews. [4][5][6][7] In addition, anchor plates in the zygomatic buttress and modified C-palatal plates (MCPPs) have been reported to distalize maxillary molars. [8][9][10][11][12][13][14][15][16] When using nonextraction treatment to achieve posterior movement of molars in adolescents, the third molars' initial position needs to be considered.…”

“…Traditionally, several devices such as headgear and pendulum appliances have been used to distalize maxillary molars during nonextraction treatment, 1‐3 but some studies achieved successful distalization using buccal miniscrews 4‐7 . In addition, anchor plates in the zygomatic buttress and modified C‐palatal plates (MCPPs) have been reported to distalize maxillary molars 8‐16 …”

Clinical applications of miniscrews that broaden the scope of non‐surgical orthodontic treatment

“…According to recent studies, the centres of resistance of the maxillary arch have been found around the mid-root of the second premolar (11.0 mm apical and 26.5 mm posterior to the incisal edge of the maxillary central incisor) 10 and that of the mandibular arch, between the second premolar and the first molar (13.5 mm apical and 25.0 mm posterior to the incisal edge of the mandibular central incisors). 11 Therefore, force vectors passing through these areas may lead to arbitrary displacement of the whole arch, according to the relationship between the specific centre of resistance and the force lines. If the line of force connecting the head of the miniscrew and the hook passes horizontally through the centre of resistance, the whole arch is moved posteriorly, viz.…”

“…Hence, when treating end‐to‐end Class II patients, the dual miniscrew can achieve clinically significant treatment results. Bechtold et al 11 also reported that for Class II malocclusion, total arch distalization using inter‐radicular miniscrews placed between the maxillary second premolar and the first molar can move the maxillary first molar posteriorly by an average of 4.2 mm without distal inclination. A mesial movement of the first molar by an average of 0.7 mm was reported during the post‐debonding observation period of about 42 months, indicating that the result of this therapy is clinically stable.…”