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Four-Rooted Maxillary First Molars: A Systematic Review and Meta-Analysis
Gabriel Magnucki1, Sven V K Mietling2
1Zahnzentrum Schomaker and Magnucki, Bahnhofstr. 16-18, Bassum 27211, Germany.
International Journal of Dentistry
|February 5, 2021
Summary
Four-rooted maxillary first molars are a rare dental anomaly occurring in 0.047% of the population worldwide. Awareness of this variation is crucial for dental professionals to prevent treatment errors during endodontic and surgical procedures.
Area of Science:
- Dentistry
- Endodontics
- Dental Anatomy
Background:
- The typical human maxillary first molar has three roots, but anatomical variations exist.
- Four-rooted maxillary first molars represent a rare and under-investigated dental anomaly.
Purpose of the Study:
- To determine the prevalence of four-rooted maxillary first molars using a meta-analysis.
- To describe the external and internal morphology of these anomalous teeth based on case reports.
Main Methods:
- A systematic search of six electronic databases for case reports and cone-beam computed tomography (CBCT) studies.
- Inclusion/exclusion criteria, critical appraisal using the Joanna Briggs Institute tool, and independent analysis of tooth morphology.
- Meta-analysis of population studies to calculate global and regional prevalence.
Main Results:
- Meta-analysis of 49 CBCT studies (26,663 molars) revealed a global prevalence of 0.047% for four-rooted maxillary molars.
- Forty-eight case reports described 53 four-rooted molars, showing worldwide distribution and variations in pulpal floor types and root canal configurations (4-7 canals).
- A significant difference in occurrence rates was observed between male and female patients.
Conclusions:
- Four-rooted maxillary first molars are a rare anomaly with a worldwide distribution.
- Dental practitioners must be aware of this anatomical variation to avoid diagnostic and treatment errors, particularly in endodontic and surgical procedures.
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