Original article
Distal movement of maxillary molars in nongrowing patients with the skeletal anchorage system

https://doi.org/10.1016/j.ajodo.2005.08.036Get rights and content

Introduction: It is now possible to predictably move maxillary molars distally in nongrowing patients with the skeletal anchorage system (SAS) and to improve malocclusions without having to extract the premolars and regardless of the patient’s compliance. The purposes of this study were to investigate the amount of distal movement of the maxillary first molars, the type of movement, the difference between actual and predicted amounts of distalization, and the relationship between the amount of distalization and age. Methods: Twenty-five nongrowing patients (22 female, 3 male) successfully treated with the SAS were the subjects in this study. The amount and the type of distalization, the difference between predicted and resulting amounts of distalization, and the relationship between the patient’s age and the amount of distalization were analyzed with wide-opening cephalometric radiographs. Results: The average amount of distalization of the maxillary first molars was 3.78 mm at the crown level and 3.20 mm at the root level. The amount of distalization at the crown level was significantly correlated with the average value of treatment goals (3.60 mm). Conclusions: The maxillary molars were predictably distalized in accordance with the individualized treatment goals without regard to patient age and extraction of the third or second molars. The SAS is a viable noncompliance modality to move maxillary molars for distally correcting maxillary protrusions and malocclusions characterized by maxillary incisor crowding.

Section snippets

Material and methods

Twenty-five nongrowing patients (22 female, 3 male) who had undergone SAS treatment at Tohoku University Dental Hospital, Sendai, Japan, were selected as subjects in this study. Twenty-two patients were treated by 1 clinician (J.S.), and 3 patients were managed by residents under his supervision. All subjects met the following criteria for case selection: (1) it was cephalometrically confirmed that they were nongrowing at least in terms of the maxillary growth before treatment, (2) there was

Results

Figure 5 is a scattergram of distal movement of the maxillary first-molar crowns and roots of all subjects. It shows the relationship between posterior displacement of the crowns and roots of the maxillay first molars individually. The average amounts of distalization at the crown and the root levels were 3.78 and 3.20 mm, respectively. The maximum crown displacement was 6.8 mm, and the minimum was 1.5 mm. The maximum root distalization was 6.0 mm, and the minimum was 1.3 mm. The correlation

Discussion

The indications for intraoral distalizing appliances that have been previously reported were mostly Class II malocclusions. But the indications for distal movement with the SAS include not only Class II malocclusions but also any malocclusions characterized by crowding of the maxillary dentition and labial inclination of the maxillary incisors in any facial types, because the SAS enables simultaneous 3-dimensional control of the maxillary and mandibular molars.38, 39, 40, 41, 42 Open-bite was a

Conclusions

The SAS is a viable modality for distalizing maxillary molars because it uses stable and strong anchorage units. It enables not only single molar distalization but also en-masse movement of the maxillary buccal segments with only minor surgery for placing the titanium anchor plates at the zygomatic buttresses. Therefore, this new noncompliance technique is particularly useful for correcting Class II malocclusions, decompensation for Class III surgical patients, and malocclusions characterized

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