The first permanent tooth to typically erupt in the oral cavity is the first molar. This tooth usually emerges around the age of 6 years, which is why it is often referred to as the "six-year molar."

- Unlike other permanent teeth, the first molar erupts posteriorly without replacing any primary tooth, making it unique in the sequence of permanent tooth eruption.
- In contrast, the central incisors and canines usually erupt later and often replace their primary counterparts.
- The second premolars erupt even later, typically during the early teenage years.

Understanding the eruption pattern is crucial for anticipating dental development milestones and planning orthodontic or pediatric dental interventions.

Key points:
- The first molar erupts around 6 years of age.
- It erupts posterior to the primary teeth and does not replace any primary tooth.
- It is often called the "six-year molar".
- Other teeth like central incisors, canines, and premolars erupt later.

Reference: Orban’s Oral Histology, Volume 1, Chapter 4, Page 120