What is the EARLIEST age at which mandibular second molar calcification typically begins?

Mandibular second molar calcification begins at approximately 2.5–3 years of age (approximately 36 months). This is within the normal developmental timeline for permanent second molars, which begin calcifying after the first permanent molars (birth) and before the premolars. The source notes 36 months as the earliest age, which aligns with standard dental development charts. Eruption of mandibular second molars occurs much later at approximately 11–13 years.