Evaluation of the Effect of Headgear on the Eruption of Maxillary Third Molars: A Longitudinal Controlled Study.

Abstract Objectives: To evaluate the short and long term effects of headgear on the third molar eruption space and the eruption status of the maxillary third molar at the long term follow up. Materials and Methods: Records were collected for 33 Class II cases treated with headgear. Three records were collected: before treatment (T1), after treatment (T2), and at the long term follow up (T3). Three corresponding time points were selected for the control sample. Lateral cephalograms were used to measure the distance from the distal surface of the maxillary first molar to pterygoid vertical (PTV). The third molar status at T3 was categorized into five groups as follows: impacted, extracted, erupted, missing, and formation stage. Results: No significant statistical difference was found between test and control groups for U6-PTV at T1 (p= 0.128) and T3 (p= 0.289). However, a significant statistical difference was found at the end of treatment T2 (p=0.000). Regarding molar status, no significant statistical difference was observed (p= 0.108). Conclusion: Headgear caused a temporary decrease in the U6-PTV distance that was recovered later on. This decrease was not observed in the control group and did not affect the eruption of the third molar. Clinical Relevance: The use of headgear to correct Class II malocclusion does not seem to increase the risk of upper third molar impaction.