Objectives

To compare skeletodental changes between early and late treatment groups using modified C-palatal plates (MCPP) and long-term retention outcomes in hyperdivergent Class II adolescents.

Materials and Methods

Seventy-one hyperdivergent Class II patients were divided into four groups according to treatment modality and treatment timing: group 1, early treatment with MCPP (n = 16; 9.9 ± 0.9 years); group 2, late treatment with MCPP (n = 19; 12.3 ± 0.8 years); group 3, early treatment with headgear (HG; n = 18; 9.6 ± 0.8 years); and group 4, late treatment with HG (n = 18; 12.1 ± 1.2 years). Lateral cephalograms were taken and skeletal and dental variables were measured. For statistical analysis, paired t-tests, independent t-tests, and multiple regression were performed.

Results

The early MCPP group showed a more significant decrease in mandibular plane angle than the late MCPP group did, and vertical control was more efficient in the early group than in the late group. In the MCPP groups, both FMA and SN-GoGn were increased with late treatment but decreased with early treatment, and the difference was statistically significant (P < .01). The early-treatment MCPP group had a significant decrease in SN-GoGn of 0.6° compared with an increase of 1.7° in the early treatment HG group (P < .01). Posttreatment stability of both the early and late MCPP groups was maintained in long-term retention.

Conclusions

Early MCPP showed more significant vertical control than late MCPP. However, there was no difference in long-term stability between early and late groups.

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Author notes

a

Adjunct Professor, Department of Orthodontics, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea University, Seoul, Korea.

b

Professor, Department of Orthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Gyeonggi Province, Korea.

c

Professor Emeritus, Department of Orthodontics, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.

d

Associate Professor, Department of Orthodontics, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.

e

Clinical Professor, Department of Orthodontics, The Catholic University of Korea; Seoul National University; and Ajou University, Korea.

f

Clinical Assistant Professor, Department of Orthodontics, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.

g

Professor and Chair, Postgraduate Orthodontic Program, Arizona School of Dentistry & Oral Health, A.T. Still University, Mesa, AZ, USA; and International Scholar, Graduate School of Dentistry, Kyung Hee University, Seoul, Korea.

The first two authors contributed equally to this work.