Effect of extraction of permanent first molars on the development and eruption of third molars

Document Type: Original Article(s)


1 Assistant Professor, Oral and Dental Diseases Research Center AND Kerman Social Determinants of Oral Health Research Center AND Department of Pediatric Dentistry, School of Dentistry, Kerman University of Medical Sciences, Kerman, Iran

2 Associate Professor, HIV/STI Surveillance Research Center, and WHO Collaborating Center for HIV Surveillance, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran

3 Assistant Professor, Department of Oral and Maxillofacial Radiology, School of Dentistry, Kerman University of Medical Sciences, Kerman, Iran


BACKGROUND AND AIM: It is required in many young patients that permanent first molars (PFMs) be extracted due to poor prognosis. This study investigates whether the extraction of such teeth is effective on the development of third molars and even their crown and root morphologies.METHODS: A total of 7000 panoramic radiographs were evaluated and 128 radiographs showing a history of extraction of PFMs on one side in one jaw or both jaws, with the third molars present in the same jaw on both sides, were selected. The third molar on the first molar extraction side was considered the case and the third molar on the other side was considered the control. The case and control third molars were compared in relation to their development, impaction, number of roots, mesiodistal width, root length, and curvature of apex. P < 0.05 was considered significant. Data were analyzed using SPSS software.RESULTS: On 128 panoramic radiographs evaluated, Olze and Demirjian factors showed that in most cases the crown development of the third molars on the control side lagged behind that on the case side. On the control side, the third molars had two roots in 66.9% and on the case side had two roots in 75.8%.CONCLUSION: Extraction of PFMs at a proper time might accelerate the development of the third molars on the same side and affect the morphologies of the crown and root(s) of third molars.


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