Lead Author Affiliation

Doctor of Dental Surgery

Lead Author Program & Year

DDS Year 2

Second Author Program & Year

DDS Year 2

Presentation Category

Research

Introduction/Context/Diagnosis

The lower lingual arch (LLA) is the most conservative treatment modality to resolve lower incisor crowding by preserving arch length in the mixed dentition. The purpose of this study was to evaluate the angular changes and incidence of impaction of the permanent second molar.

Methods/Treatment Plan

612 panoramic radiographs were analyzed by two students using dolphin imaging to quantify the angular changes of the lower second molar and examined for second molar impaction at T1 (mixed dentition) and T2 (permanent dentition) timepoints of orthodontic treatment. 97 patients (47 males and 50 females) were included where a total of 38patients with LLA were compared to a control group of 59 patients who did not receive space maintenance therapy with an LLA. The samples were collected retrospectively from a private practice. For statistical analysis, Intraclass correlation coefficient (ICC) and an independent t-test was used.

Results/Outcome

Inter-judge reliability using intraclass correlation coefficient were excellent, 0.95. The mean angulation shift (change of the 2nd molar) from T1 to T2 timepoints in patients treated with an LLA was 2.3 ±8.4° compared to 4.2 ±7.9° in the control group. The difference was not statistically significant (p= 0.52). At T2. The mean angle of the 2nd molars was slightly greater in the LLA group compared to the control group, 11.2±6.6° vs 9.0±5.7° respectively, but the difference was not statistically significant. The prevalence of mandibular second molar impaction was 7.6% in patients with LLHA compared to 4.4% in the control group; the difference was not statistically significant (p=0.11).

Significance/Conclusions

The lower lingual holding arch is not associated with an increased risk of second molar impaction in patients being treated in the mixed dentition.

Comments/Acknowledgements

We would like to thank Dr. Heesoo Oh, whose expertise was invaluable in formulating our research methodology and guiding us throughout throughout the project. We would also like to thank Dr. Steve Dugoni who provided us with the panoramic radiographs needed to conduct the study.

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Angular Changes and Impaction Incidence of Mandibular Second Molars in Mixed Dentition LLHA Treatment

The lower lingual arch (LLA) is the most conservative treatment modality to resolve lower incisor crowding by preserving arch length in the mixed dentition. The purpose of this study was to evaluate the angular changes and incidence of impaction of the permanent second molar.