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Formation and development of maxillary first molars with delayed eruption
Natsuki Sano1, Takashi Kameda2, Yukari Terashima2
1Department of Orthodontics, The Nippon Dental University School of Life Dentistry at Niigata, 951-8580, Hamaura-chou 1-8, Chuuou-ku, Niigata, Japan. natsuki@ngt.ndu.ac.jp.
Odontology
|July 12, 2014
Summary
Delayed eruption of the maxillary first molar (M1) is rare but occurs. Despite a delayed start, M1s develop and erupt faster than usual, aiding orthodontic treatment planning.
Area of Science:
- Dentistry
- Orthodontics
- Pediatric Dentistry
Background:
- Congenitally missing or delayed eruption of the maxillary first molar (M1) is uncommon.
- Recent observations suggest an increase in suspected M1 delayed eruption or absence.
- M1s are crucial for proper occlusion.
Purpose of the Study:
- To analyze the formation and eruption patterns of delayed erupted maxillary first molars (M1).
- To compare the development and eruption timelines of M1 with normal maxillary first molars (U6).
- To provide insights for orthodontic treatment planning in cases of M1 anomalies.
Main Methods:
- A retrospective analysis of patients born between 1974-1994 with M1 anomalies.
- Evaluation of panoramic X-rays from 73 patients (131 M1s) using Moorrees's tooth formation stages.
- Fitting development/growth curves (logistic and U6) to M1 formation and eruption pathways.
Main Results:
- The frequency of M1 anomalies was 1.55% in the studied cohort.
- M1 development and eruption curves showed a faster inclination compared to U6 after an initial delay.
- The eruption pathway of M1 followed a sigmoid S-shape curve.
Conclusions:
- Despite a delayed onset, the developmental and migration speed of M1 is accelerated.
- Understanding these accelerated dynamics is vital for effective orthodontic treatment planning for M1 anomalies.
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