Changes In Intermaxillary clearance As a Result of Altering The Vertical Dimension

Objectives: The objective here was to clinically evaluate the average opening ratio in the molar area in relation to the extent of opening in the incisor area.
Methods: 37 adults, with full dentition and stable occlusion participated in the current study. Vertical distance change was evaluated in three areas: between the upper and lower central incisors, canines and between the first molars. Standardization was performed using digital photography taken at three positions: intercuspal position (ICP), 2mm VD increase and 8mm increase.
Results: Data collected showed that the average ratio of the opening between the first molars and the opening between the central incisors was 0.73±0.036, i.e. 1 mm of vertical dimension opening between the central incisors resulted in 0.73 mm of occlusal clearance in the first molar region. The average ratio of the opening between the canines and the opening between the central incisors was 0.95±0.03. The values were plotted and a mathematical model was deducted.
Conclusions: Modifying the OVD for therapeutic needs may be optimized by preliminary planning. The ratios at different locations can be calculated in advance using a mathematical model provided here for calculating the degree of incisor or molar separation for a specific opening at the articulator’s incisal pin.