A dental is a stop. Stops are the pure consonants, and they are divided into three groups, depending on what part of the speech organ is used to stop the air before the sound of the letter is made. A dental is a stop that is created when the tongue restricts the air by coming into contact with the teeth and blocking the escape of air. Notice the role that the teeth play in the creation of these sounds.

Try making the sounds of dentals (delta, theta, tau / d, t, th). You will easily see the role the teeth play in blocking the escape of air in the process of forming this stop.

Note that all three Greek dentals are in the phrase "the dental." The other consonants in this phrase are not stops.