2017 Volume 55 Issue 3 Pages 375-381
In studies published prior to 1980 that studied the order of eruption of the central incisors, lateral incisors, and first molars of the lower jaw, the first molar was found to most often erupt first. In contrast, in those published since 1980, the percentage of children in whom a central incisor was first to erupt is the greatest. These findings indicate that the order of eruption of permanent teeth of the lower jaw may have changed after 1980. Here, we investigated the order of eruption of the central incisors,lateral incisors, and first molars in a longitudinal study of 105 pediatric patients in stages ranging from deciduous dentition to Hellman's dental stage III B. The following results were obtained.
1.There was no significant difference in order of eruption between genders or side of the jaw. However, there was a significant difference between the upper and lower jaws.
2.The most frequently observed order of eruption in the upper jaw was first molar (6), central incisor (1), and lateral incisor (2), while that in the lower jaw was 1-6-2.
3.There was no significant difference between the frequencies of 1-2-6 and 1-6-2 in the upper jaw, or between the frequencies of 1-6-2 and 6-1-2 in the lower jaw.
4.There was a significant difference for mesiodistal diameter of the crown of the lateral incisor in the upper jaw between patients in whom a central incisor had erupted first and those in whom a first molar had erupted first in the lower jaw.
We found no significant difference in regard to the first erupted tooth in the lower jaw of our patients. Nevertheless, we cannot conclude that the order of eruption has changed since 1980, as it is possible that the mesiodistal diameter of the crown has effects on the order of eruption, which we intend to examine in future studies.
