Among the permanent teeth, the first permanent molars play the greatest role in occlusion and function. So, the congenital missing, abnormal reuption or abnormal formation of the first permanent molars in the course of arch development would
inflict
normal development of dental arches. Therefore, early detection of abnormal cases related to first permanent molaras and understanding of current and predictable clinical p[roblems are essential for proper occlusal guidance in children.
With the aim of investigating the clinical patterns of delayed eruption of first permanent molars in children, panoramic tomograms of the children in mixed and early permanent dentition were observed and analyzed
@ES The reuslts were as follows:
@EN 1. Among the delayed eruption of first permanent molars, on tooth or bilateral teeths were affected most frequently. Delayed eruption was more prevalent in maxilla than in mandible.
2. The formation of tardily erupted teeth were also delayed.
3. Delayed eruption was generally limited in first molars or molar segmonts.
4. Delayed eruption of first permanent molars is accompanied by abnormal position of tooth germs, for example, ectopic eruption, delayed dental age, delayed localized tooth formation and generalized congenial missing.
5. There was a tendency of delayed formation or congenital missing of second molars distal to tardily erupted 1st molars. And that was more marked in maxilla than in mandible.
6. There was reported that affected 1st molars show various size and shapes. Maxillary 1st molars showing delayed cruption showed a tendency of having 3 cusps. But, tardily erupted mandibular 1st molars showed no significant reduction in
mesiodistal
dimension, as reported.
7. In some cases, the delayed eruption of 1st permanent molars was associated with ectopic erutpion, but their formation was not usually retarded.
8. In skeletal class III cases, there showed a tendency of mandibular 1st molars to erupt earlier than maxillary 1st molars with greater interval than in normal occlusion.
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