disocclusion
/dɪsəˈkluːʒn/noun
1 Dentistry. Failure of opposing teeth to make contact (when the jaws are closed); an instance of this.
2The exposure of something to view or reappearance of something hidden from view (as a result of a change in the observer's perspective, removal of an obstruction in the line of sight, etc., or as a phenomenon in various types of image production); an instance of this.
Origin
1920s; earliest use found in Dental Items of Interest. From dis- + occlusion.