Within the standard for each breed is specifications as to what is the acceptable parameters for bite. For most breeds the scissors bite is ideal.
Scissors bite is one in which the upper incisors just overlap and touch the lower incisors.
There is a gap between the upper and lower incisors when the mouth is closed. Some puppies that are born with an overbite might self-correct if the bite is no larger than the head of a wooden match. An overshot bite will rarely improve after the puppy reaches ten months. Some puppies with overshot bites will experience difficulties when their permanent teeth come in. Due to the increased size of the permanent teeth, as they come in they can damage the soft parts of the mouth.