Third molar angulation changes in Class II div I malocclusion subjects treated with extraction of four premolars: A retrospective study

Abstract

A BSTRACT Aim: The aim of this study was to assess the changes in maxillary and mandibular third molar inclinations in individuals with class II div 1 malocclusion, before and after orthodontic treatment with extraction of all four first premolars. Materials and Methods: This retrospective study consisted of the pretreatment and posttreatment records of 30 patients that were obtained from the archives of the department of orthodontics and dentofacial orthopedics in A B Shetty Memorial Institute of Dental Sciences. The maxillary third molar’s relation to the palatal plane and the mandibular third molar’s relation to the mandibular plane were measured. The paired t test was used to calculate pre- and posttreatment changes. A value of P < 0.05 was considered to be statistically significant. Results: The maxillary third molars showed a mean correction of 6.15° ( P < 0.001) and the mandibular third molars showed a mean correction of 5.10° ( P < 0.001). Conclusion: Maxillary third molars showed more uprighting when compared to the mandibular third molars and that both maxillary and mandibular third molars showed an improvement in their angulations to their respective planes after extraction of the first premolars. However, the results of the study cannot be analyzed to state if the third molars do become fully functional.

Effect of orthodontic extraction of mandibular premolars on third molar angulation after treatment with fixed appliances

“…In as much, a variety of reference points has been used by various researchers to estimate the angulation of the third molar. Thus, the mandibular plane has been utilized as a reference plane in other studies [4,31,43] of which only Shashidhar et al [31] found a statistically significant difference in the alteration of the angulation of the lower third molar by examining only cephalometric x-rays, whereas the other two studies examined both cephalometric and panoramic x-rays. Moreover, the Frankfurt plane was used as the reference plane by two studies [14,39], which both examined panoramic x-rays and found no difference in the angulation of the lower third molar before and after the orthodontic treatment between an extraction and non-extraction group.…”

“…In our study, we evaluated the angle formed between the long axis of the third lower molar and the long axis of the second lower molar. According to Shashidhar et al [31], this is not a stable measurement as the second molars can be tipped in a mesial/distal/lingual/buccal direction prior to the start of the treatment and then get corrected during orthodontic treatment. To avoid the implication of the second molar's spatial orientation in investigating the third molar angulation, the lower third molar angulation was evaluated only in the posttreatment OPG.…”