At the age of four years, what do x-rays typically reveal regarding the calcification of teeth?

At the age of four years, x-rays typically reveal that most of the permanent teeth, excluding the third molars, are in various stages of calcification. By this age, the first permanent molars have begun to calcify, and other permanent teeth are also starting to develop beneath the gums.

Deciduous teeth are usually already present and visible, but the focus of this question is on the permanent teeth, which are still developing and becoming observable on x-rays.

The third molars, however, do not begin to develop until later in childhood, often around the ages of 8-10 years. Therefore, they would not appear in an x-ray taken at age four. This knowledge of dental anatomy and the timeline of tooth development supports the reason behind the correct answer.