What is the dental eruption timeline for primary teeth?

• A. Primary teeth begin erupting around 6–10 months and are typically complete by about 30–36 months.
• B. Primary teeth begin erupting around 12–24 months and are complete by 5 years.
• C. Primary teeth begin erupting around 4–6 months and are complete by 24 months.
• D. Primary teeth begin erupting around 18–24 months and are complete by 42 months.

Answer: (A)

Primary teeth typically begin to erupt around six to ten months, and the full set is usually in by about thirty to thirty-six months. This timing is what clinicians use as the common eruption window for deciduous dentition. While individual variation exists—some babies may start a bit earlier or later—the overall pattern sits within this 6–10 month onset and 30–36 month completion range. The eruption sequence also tends to follow a predictable order (lower central incisors first, then upper central incisors, followed by lateral incisors, first molars, canines, and second molars), which supports this timeline as the standard reference. Other proposed timeframes either push onset earlier than is typical or extend eruption well beyond the third year, making them less consistent with common developmental patterns.