Mendelian dominant trait involved with Hypodontia
Hypodontia isn't a single gene phenotype, but a poli-genic mechanism involved with epistatic phenomenons and environmental scenarios. 

The trasmission isn't clear till now, but when you're talking about a poli-gene phenotype isn't so easy to describe the way in which the trasmission is performed. You could find every info about this disease here, in a meta-review study: