Objective: Orthodontic treatment using the implant anchorage can move mandibular teeth distally, thus might affect the tongue position and the pharyngeal airway. However, there are a few studies that investigated the linkage. The aim of the study was to analyze the relationship among the tongue position, the pharyngeal airway and the distal movement of mandibular dentition in orthodontic treatment using the implant anchorage.
Methods: The cephalometric radiographs of patients who had undergone orthodontic treatment without extraction of the lower teeth except for the mandibular third molars were analyzed. Samples were divided into the two group; those treated with the skeletal anchorage (SMAP, Dentsply, Tokyo, Japan) to distalize the whole mandibular dentition, and those treated with Class III elastics. We measured the amounts of displacement of the lower incisor (DL1) and the lower first molar (DL6), and the upper, middle, and lower pharyngeal airway depth (PAD). We also measured the parameters of the hyoid bone position (HBP) using a set of the lateral cephalograms before and after orthodontic treatment in both groups, according to the definition in the literature.
Results: There was a significant difference in DL1 and DL6, while there was no significant difference in the upper, middle, and lower PAD between the two groups. Moreover, there were no significant changes in the HBP between the two groups.
Conclusions: This is the first preliminary study to evaluate the influence of orthodontic treatment using the implant anchorage on the tongue position and the pharyngeal airway.