Relationship between formation and eruption of permanent mandibular buccal dentition and vertical height of the mandibular body: longitudinal study of Japanese boys from 4 to 9 years of age.

ABSTRACT

AIM: To examine the relationship between the formation and eruption (vertical tooth movement in and through the alveolar bone) of the permanent mandibular buccal dentition and vertical height of the mandibular body. METHOD: Mandibular morphology and tooth formation and eruption were analyzed from cephalograms taken annually on each birthday month from 4 to 9 years of age. RESULTS: From 4 to 6 years of age, before active tooth eruption, there was a significant positive correlation between the vertical height of the mandibular body and the distance from the permanent mandibular buccal dentition to the occlusal plane. There was a significant positive correlation between the vertical height of the mandibular body at 6 years of age and the subsequent annual amount of tooth eruption in the mandibular buccal dentition. Simple linear regression equations were obtained to predict the amount of mandibular buccal tooth formation and eruption from the vertical height of the mandibular body at 6 years of age. CONCLUSION: The larger the mandibular vertical height, the larger the distance from the buccal dentition to the occlusal plane before active eruption, and the larger the amount of tooth eruption during the active eruption period. The vertical mandibular morphology is useful to predict the formation and eruption of the mandibular buccal dentition.