Maxillary expansion efficiency with clear aligner and its possible influencing factors
10.3760/cma.j.issn.1002-0098.2017.09.006
- VernacularTitle: 无托槽隐形矫治上颌扩弓效率及其影响因素初探
- Author:
Xiang ZHAO
1
;
Honghong WANG
1
;
Yiming YANG
1
;
Guohua TANG
1
Author Information
1. Department of Orthodontics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine & Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology & National Clinical Research Center of Stomatology, Shanghai 200011, China
- Publication Type:Journal Article
- Keywords:
Orthodontic appliances, removable;
Efficiency;
Clear aligners;
Treatment outcome
- From:
Chinese Journal of Stomatology
2017;52(9):543-548
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the efficiency of maxillary expansion with clear aligners and to analyze the possible influence factors.
Methods:Thiry-one clear aligner cases (Invisalign) with maxillary expansion were enrolled in this study. The three-dimensional (3D) digital models of pre-treatment, planned in Clincheck software and post-treatment were collected. Upper dental arch width, buccal inclination of posterior teeth, and the expansion efficiency (expansion acquired/expansion planned) were measured and calculated. The impact of factors such as planned buccal inclination, planned expansion amount, attachment, and the mode of expansion on the expansion efficiency were analyzed.
Results:The increases of upper arch width in canine, 1st and 2nd premolar, 1st and 2nd molar were (2.0±1.3), (2.8±1.5), (3.0±1.4), (1.8±1.0) and 0.5 (0.1, 1.1) mm, with their efficiency of 68%, 70%, 68%, 55% and 29%, respectively. The posterior teeth showed significantly more buccal inclination than the planned position (P<0.05). However, the most buccally inclined tooth detected in 1st molars was only 3.1°±3.9°. When the planned inter-molar width increase was less than 2 mm (n=15), the expansion efficiency of premolars was higher compared with those cases with the planned inter-molar width increase more than 2 mm (n=16, P<0.05). The planned buccal inclination, attachments, and the expansion mode had no significant effect on the expansion efficiency (P>0.05).
Conclusions:The expansion of maxillary arch with clear aligners was achieved by the buccal movement of the posterior teeth with limited buccal inclination. The efficiency of expansion declines from 1st premolars to second molars. The planned inter-molar width had a significant influence on the efficiency of premolar expansion.
