Ashraf I. Shaweesh,
Duration and rate of clinical eruption of third molars
Dental Oral Biology and Craniofacial Research
2019
2613-4950
http://dx.doi.org/10.31487/j.DOBCR.2019.01.002
https://www.sciencerepository.org/duration-and-rate-of-clinical-eruption-of-third-molars_SR-DOBCR-2019-1-102 
Abstract: Objectives: The aim of the current paper was to present norms of clinical duration and rate of
eruption for upper and lower 3rd molars utilizing recently published data for a Jordanian population.
Methods: Duration of Clinical Eruption (CDE) in years and Clinical Eruption Rates (CER) in
mm/year were calculated from recently published median ages at emergence and functional eruption
of 3rd molars for a Jordanian population.
Results: Third molars clinically erupt at a rate between 1.45 to 1.85 mm/year, being slightly faster
in the lower jaw. The average CDEs were 2.95 and 2.75 years for upper and lower 3rd molars
respectively. Upper 3rd molars of males needed a slightly longer CDE than lower 3rd molars did while,
in females, there was no difference in CDE across arches. The average CERs were 1.53 and 1.82
mm/year for upper and lower 3rd molars respectively. In contrast to males, females exhibited slightly
faster CER for the upper 3rd molar and slightly slower CER for the lower 3rd molar. CERs are steadier
and more linear in the upper than in the lower 3rd molar.
Conclusions: This study has reported the first norms of duration and rate of clinical eruption specific
to upper and lower 3rd molars. Normally, third molars remain around 3 years in clinical eruption,
which render them more vulnerable to recurrent pericoronitis and other local pathologies than the rest
of the teeth. The availability of these norms will help dentists and auxiliaries identify and diagnose
delayed and slow eruption cases and make their clinical decision upon removing or keeping 3rd
molars.Keywords: Clinical eruption, duration of eruption, eruption rate, third molars