Dentition Eruption Sequence

The human deciduous dentition begins to emerge into the mouth at about 6 months after birth and is completely established by 3 years of age or even earlier. The usual sequence of eruption is i1: i2: dm1: c: dm2. The deciduous teeth of great apes have begun to emerge by 3 or 4 months after birth and are completely erupted by 12 or 14 months. The usual sequence is i1: i2: dm1: dm2: c. There is variation in which of the incisors emerge first and it is noteworthy that the canine is usually the last deciduous tooth to emerge in great apes and not the dm2 as in humans. The human permanent dentition begins to emerge at about 6 years of age and is complete by ~18 years. The sequence of emergence is very variable but is essentially, I1: M1: I2: Pm3: C: Pm4: M2: M3. The permanent first molar and lower first incisor may reverse their sequence (there may be a secular trend for I1 to erupt earlier) and the premolars, canine and second permanent molar erupt so close together in time that changes in the sequence are common, especially when deciduous teeth are shed early or late. Great ape permanent teeth begin to erupt at ~3.5 years of age and complete around 12 years. M1 is the first permanent tooth to emerge and always precedes the permanent incisors, which erupt in time much closer to the second permanent molars. There is then a variable sequence of I2 and Pm3 or PM4 emergence. M2 has even been observed to emerge before I2. The large sexually dimorphic great ape permanent canine emerges before the M3 but takes a long time to come into full occlusion such that M3 is usually well established in functional occlusion long before the canine.