Study of the point B alterations during orthodontic treatment

José Soares MARQUES, Vania Célia Vieira de SIQUEIRA

Aim: The authors of this study evaluated and compared if alterations in point B region could occur as a result of orthodontic treatment conducted with or without the extraction of the four first premolars. Methods: Thirty young females, dolicofacials, with Class II, division 1 maloclusion, mean age of 12,3 years in the beginning of the treatment were evaluated cephalometrically. Fifteen of the young females were submitted to extractions of the four first premolars while the remaining fifteen were not. Four cephalometric measurements (IMPA, 1-ND, B-ND and BperpGoMe) were evaluated and data was analyzed by the Kruskall-Wallis test, Friedman test and Pearson’s correlation. Results: The IMPA measurement had a tendency to increase within the group without extractions, but in contrast was significantly decreased within the group with extractions. The 1-ND measurement exhibited a decrease in the group with extractions and a small increase in the other group. The B-ND measurement was slightly decreased in the group with extractions, was not altered in the other group, and significant differences were not observed between these two groups. The Bperp-GoMe measurement was increased in both groups. A positive correlation was observed between IMPA, 1-ND and B-ND in the extraction group, since a decrease of the IMPA implied in a decrease of the 1-ND and a lingual localization of the point B. Conclusions: Together, these results showed that the orthodontic treatment lead to alterations in point B, towards an anteroposterior position, and a tendency of lingual movement in the extraction group. The vertical evaluation revealed significant alterations in point B in both groups since measurement at the end of the treatment was significantly higher than the one in the beginning.

Keywords: Point B. Orthodontic treatment. Extractions. Class II. Mandibular remodeling.

Thursday, May 02, 2024 14:33