Objectives: The aim of this paper is to present a novel bone-borne maxillary expansion technique and to analyze expansion pattern of maxillary dentition and skeleton.
Methods: For a 26-year old male with an anterior open bite and significant narrowness of maxillary arch, a hyrax appliance was modified and attached to his palate with two 2mm-diameter and 10mm-length mini-screws on each side at 5mm lateral to mid-suture. Four 1.4mm-diameter and 8mm-length mini-screws were placed in palate, distal of canines and first molars, as skeletal indices. A sub-Lefort I osteotomy was done under general anesthesia. After 7 days latency period expansion starts with rate of 0.8mm and rhythm of 2 times per day. Skeletal changes were measured intra-orally through skeletal indices and dental changes were measured through cast analysis.
Results: After 9.6mm hyrax opening, the following increases at transverse dimensions were obtained.16.26 mm diastema,14.61 mm at inter-canine width,9.89 mm at inter-molar width,11.35 mm at anterior skeletal indices region,6.99 mm at posterior skeletal indices region.
Conclusion: This technique can be an effective therapeutic method for bone-borne maxillary expansion and spares negative side effects of tooth-borne techniques.