[Considerations regarding a prediction method for third mandibular molar eruption].

UNLABELLED: Third mandibular molar eruption is an unpredictable event.

MATERIAL AND METHOD: We have studied 250 patients who required orthodontic treatment in the Department of Orthodontics and Dentofacial Orthopedics, University of Medicine and Pharmacy "Gr.T. Popa" Iaşi. Orthopantomograms were traced for all patients at the beginning of the orthodontic treatment. Some patients presented first lower molar removal before orthodontic treatment.

RESULTS

We evaluated the difference between posterior available space and third lower molar mesiodistal dimension in order to establish the predictable values for third molar eruption. Our results show that only 17% of lower third molars have 100% chances for eruption in non extraction sample, comparative with 65-70% in extraction group. 38% of third mandibular molars have a poor prognosis for eruption in non extraction group and only 14% for the pretreatment extraction group.