American Board of Orthodontics (ABO) Practice Exam 2026 - Free Orthodontics Practice Questions and Study Guide

Eruption of a tooth typically begins when a significant portion of the root development is complete. Research indicates that this process starts around the time when approximately three-quarters of the final root length has formed. This stage is critical for the tooth to gain sufficient structural integrity to withstand the forces encountered during the eruption process.

As the root develops, it aids in stabilizing the tooth in the bone and is involved in the overall eruption pathway. The completion of about three-quarters of the root length ensures that the tooth is prepared for eruption while still allowing for some growth and adjustment as it ascends through the gum tissue.

It's important to note that eruption will not commence if the root is underdeveloped, as this could lead to complications such as impaction or misalignment. Thus, the establishment of three-quarters of the root length is a key developmental milestone that signals readiness for the eruption process.