A retrospective comparative cephalometric evaluation of non-extraction multiloop edgewise archwire and bicuspid extraction therapies in anterior open bite treatment

Objectives: This study aimed to compare treatment efficacy and cephalometric outcomes between extraction and non-extraction MEAW therapies in non-growing open-bite patients.

Materials and methods: 22 Multiloop Edgewise Archwire MEAW patients (11 males, 11 females) and 15 bicuspid extraction patients (3 males, 12 females) were selected according to a strict inclusion criterion. Comprehensive data collection related to age, sex, Cervical Vertebral Maturation CVM staging, and severity of the Anterior Open Bite AOB (1 = 0-1 mm; 2 = 1-2 mm; 3 = > 2.1 mm) was performed independently and in duplicate by 2 examiners. Each included patient's pre and post-treatment lateral cephalograms were traced and compared. The primary outcomes assessed were related to the efficacy of treatment: treatment duration and time needed to achieve a positive overbite. The secondary outcomes assessed were related to the post-treatment changes in cephalometric measurements between the groups. Descriptive statistics, Mann-Whitney U test, unpaired student's t-test, and Chi-squared were used for data analysis.

Results: The mean change in open bite closure was 3.07 ± 2.07 mm in the MEAW group and 3.03 ± 2.28 mm in the extraction group (P > 0.05). MEAW therapy was 31% faster (118 weeks) than extraction therapy (171 weeks, P = 0.004). MEAW appliance showed a significantly shorter duration for open bite closure (71.82 ± 29.57 weeks) compared to the extraction group (127.25 ± 51.97 weeks, P = 0.002). A greater decrease in the U1-SN was seen in the extraction group (-8.70 ± 6.49°), compared to the MEAW group (-2.56 ± 7.36°, P = 0.047). The IMPA angle showed a greater decrease in the extraction group (-8.30 ± 8.85°) compared to the MEAW group (-0.90 ± 6.50°, P = 0.032). The (L6-MP perp) increased in the extraction group by (1.98 ± 3.43 mm), while decreased in the MEAW group (-0.43 ± 1.38 mm, P = 0.023).

Conclusion: In anterior open bite cases with bicuspid extraction, achieving a positive overbite typically involves retroclining and uprighting the upper and lower incisors (drawbridge effect). In contrast, the MEAW appliance focuses on uprighting the entire dentition and intruding the posterior teeth, often leading to shorter treatment durations.

Clinical relevance: The MEAW appliance's biomechanical advantage in uprighting posterior teeth in open bite cases may shorten treatment duration for correcting open bite malocclusion.