- The first permanent molar is the tooth that typically erupts between the ages of 6 and 7 years.
- This eruption is an important milestone in dental development because it marks the beginning of the transition from the primary (deciduous) dentition to the permanent dentition.

Key points to note:
- The first permanent molar erupts distal to the second primary molars, meaning it comes in behind the existing baby teeth without replacing any primary tooth.
- It is often called the "6-year molar" due to its characteristic eruption timing.
- This tooth plays a critical role in establishing the permanent occlusion and proper alignment of other permanent teeth.
- Unlike incisors and canines, which replace primary teeth, the first permanent molar erupts into a space that was previously unoccupied by any primary tooth.

In contrast:
- The central incisors usually erupt slightly later, around 6-8 years.
- The second permanent molars typically erupt between 11 and 13 years.
- The canines generally erupt between 9 and 12 years.

Understanding the eruption timeline helps in diagnosing delayed eruption, crowding problems, or other developmental dental issues in children.

Reference: Orban's Oral Histology, Volume 1, Chapter 4 / Page 76