The 53rd Annual Scientific Congress of the Korean Association of Orthodontists PASSION FOR A LONG JOURNEY :
Nature vs Nurture

November 5(Thu) - 6(Fri), 2020
Precongress: November 1(Sun) / VOD: November 7(Sat) - 8(Sun)

Protrusion problem

Statics and dynamics of protrusion: quest for total arch movement
Dr. Kee-Joon Lee
  • Affiliation
  • Professor and Chairman, Department of Orthodontics, Yonsei University College of Dentistry
  • Address
  • 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea
  • Dr. Kee-Joon Lee is professor and chairman of the Department of Orthodontics, Yonsei University College of Dentistry, Korea. He received DDS and PhD degree from Graduate school, College of Dentistry, Yonsei University. He completed the orthodontics specialty training in Yonsei University. He was a visiting scholar at the Department of Biochemistry, University of Pennsylvania School of Dental Medicine in 2002-2004 and at the Division of Plastic Surgery, the Children's Hospital of Philadelphia in 2010-2011. He is currently an adjunct professor at the Department of Orthodontics, University of Pennsylvania. He is one of the founding members of the Korean Association of Lingual Orthodontists. He has contributed many book chapters on biomechanics of miniscrew-driven orthodontics, non-extraction treatment in adults, up-to-date lingual orthodontic mechanics and surgery-first approached using TADs. He is the first who demonstrated the miniscrew-assisted rapid palatal expander (MARPE) for adults in AJO-DO and has published many articles regarding the treatment of non-eruption, and total arch movement for hyperdivergent face in orthodontic journals including two cover issues in AJO-DO. His fields in research include clinical biomechanics regarding TADs application and the suture and bone responses to orthodontic stimulus. He has served as a reviewer in major orthodontic journals, including AJO-DO, Angle Orthodontists and European Journal of Orthodontics. He has been invited to numerous international orthodontic conferences around the world.

Some soft tissue phenotypes such as lip incompetency and mentalis hyperactivity have been a significant contributor for facial aberrancy causing lip protrusion at (dynamic) forced lip closure, rather than at rest (static) position. Vertical growth or clockwise jaw rotation may exacerbate the incompetency, which contributes to the convex profile regardless of dental protrusion. To alleviate the vertical discrepancy, orthopaedic vertical correction has been suggested in the literature, with scarce clinical effects. In general, the vertical control for hyperdivergent face has been considered highly challenging due to its genetic nature. A simultaneous displacement of the whole arch, named as total arch intrusion using miniscrews may be suggested as an alternative. Its feasibility, treatment outcome and the validity will be extensively discussed in the following aspects.

1) Diagnosis and etiology
Our clinical statistics revealed no significant relationship between vertical hard and soft tissue phenotypes. Therefore, it is reasonable to recognize the vertical facial morphology based on soft tissue phenotypes.

2) Biomechanics of labial/lingual total arch intrusion
Considering the strong genetic nature of the circummaxillary sutures, it is conceivable to conduct major dentoalveolar intrusion rather than suppression of sutural growth. The total arch intrusion in both labial and lingual orthodontics will be demonstrated based on the known centers of resistance of the entire arch. Depending on the time point when the total arch intrusion was performed, the clinical outcome may vary. Moreover, clinical effects of four-dimensional total arch intrusion will be demonstrated.