Study on Factors Associated with Spontaneous Mesialization of Impacted Mandibular Third Molars during Orthodontic Treatment

doi:10.13701/j.cnki.kqyxyj.2023.09.008

Abstract

Abstract: Objective: To investigate the factors associated with spontaneous mesialization of impacted third molars after second molar protraction. Methods: Forty-seven orthodontic patients [12 males and 35 females; mean age: (17.36±3.69) years] from Urumqi Stomatological Hospital treated with mandibular second molar protraction to close the space due to missing L-6 or L-E were selected, with the total number of missing molars was 66. The CBCT image data of mandibular second molar before treatment (T0) and after the anterior closure of missing space (T1) were accurately measured and analyzed. The correlation factors affecting the spontaneous mesial movement of the third molar were discussed by regression analysis. Results: Mandibular second molars were protracted by (5.61±2.46) mm and (6.28±3.19) mm measured at the crown and root furcation, respectively. After second molar protraction, third molars showed spontaneous mesialization by (5.16±2.00) mm and (4.47±2.72) mm, measured at the crown and root furcation, respectively. The distance of the second molar crown (P<0.05), the distance of the root furcation (P<0.05), Nolla’s stage of the third molar at T0 (P<0.05) and second molar protraction time (P<0.05) were significantly associated with the amount of third molar mesialization. Conclusion: Greater third molar mesialization was observed when Nolla’s stage of the third molar was higher before treatment and when the second molar protraction distance and time was longer.

Key words: impacted third molar, missing posterior teeth, molar protraction

FAN Yaru, MENG Qingfang, WU Qianqian. Study on Factors Associated with Spontaneous Mesialization of Impacted Mandibular Third Molars during Orthodontic Treatment[J]. Journal of Oral Science Research, 2023, 39(9): 804-809.

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