INCREASE OF VERTICAL DIMENSION - CONSEQUENCES FOR THE MAXILLOMANDIBULAR RELATIONSHIP - A CLINICAL APPROACH

The purpose of the present study was to compare the vertical change in the incisor and molar areas caused by insertion of a bite opening app liance and to analyse the occurrence of rotation and eruption during t he following treatment period (mean 4.3 months). Eight patients betwee n 15 and 24 years of age with vertical overlaps greater than or equal to 4 mm were treated by means of a maxillary fixed lingual arch applia nce with an anterior bite plane. The retruded mandibular position was recorded with cold cure acrylic before treatment, immediately after in sertion of the fixed appliance, and after removal of it. Vertical over lap and separation between the first molars was measured at each of th ese occasions. Finally, tooth movements during eruption were measured on the indices in the area of the second molar. The results showed tha t, independent of the amount of bite raise, the relation between front al and molar area bite raise was approximately 2:1 for six and 5:3 for two patients. There was a significant difference in thickness of indi ces from registrations I and III in the second molar area indicating n ot only eruption during bite opening therapy but also buccolingual rot ation.