Which one of the following average age ranges shows that of the usual eruption date of the upper second permanent molars?

The average eruption date for the upper second permanent molars typically occurs between the ages of 12 and 13 years. This is an important milestone in dental development, marking the transition where the primary teeth are being replaced by permanent teeth.

The upper second molars are considered part of the normal sequence of tooth eruption, which follows a general pattern: first permanent molars usually emerge around age 6, followed by the incisors, and then the canines. The second molars appear later in this developmental timeline. By the age of 12 to 13, most individuals have completed the transition of primary teeth to permanent ones, and the second molars are ideally positioned to erupt due to the overall growth of the jaw and the eruption of adjacent teeth, spacing appropriately for their arrival.

In contrast, the other age ranges provided do not align with the eruption schedule of the upper second molars. For example, the ages 3-4 years and 6-7 years generally correspond to the eruption of primary teeth and the first permanent molars, while the 9-11 years range is typically associated with the eruption of the upper premolars and lower second molars rather than the upper second permanent molars. Thus, the 12