AimConventional devices for surgical assisted rapid palatinal expansion are either tooth or bone borne. During clinical application over years, system dependant deficiencies, using either device became apparent. So together with Normed, Tuttlingen, we developed a new bone borne distractor (MWDTM, Maxillary Widening Device). In this article we introduce this distractor and present our first experiences in using this device.Patients and MethodsIn this study, 20 patients suffering from maxillary arch compression with anterior crowding were treated using MWDTM in combination with Glassman's modified Le-Fort-I-osteotomy. Additionally the MWDTM was inserted in two cleft lip and palate patients, as well as one patient with bilateral microsomy.ResultsThe MWDTM turned out to be a safe, easy to handle and reliable bone borne distractor leading to excellent results. The MWDTM can be used in early adult as well as in syndromal patients. In early adult patients the complication rate averaged 25%, widening averaged 7,6 mm. Relaps was not discovered.ConclusionThe MWDTM turned out to be a reliable, stable and user-friendly device leading to excellent results.