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)


Strategic molar movement using mini-screw for long-term stability
Dr. Ju Young Lee
  • Plus 1 Orthodontics, Suwon, South Korea
  • Dr. Ju Young Lee is one of enthusiastic lecturers about Mini screw (TADs) in South Korea. He has taught students at Orthodontic program of 5 Universities (KyungHee University, Catholic University, Ajou University, Korea University, and SungKyunKwan University) over 15 years. He was Adjunct Associate professor of Department of Orthodontics and Dentofacial Orthopedics of Loma Linda University in California, USA for 10 years.

    He has endeavored to develop and extend the clinical usage of mini screw (TADs) since he has started to use it since 2000 and hope to share his 20 years' of experience about Mini screw (TADs). He also has interested in Lingual orthodontic treatment since 1995 and became a founding member of Korean Lingual Orthodontic Association (KLOA) and active member of World Society of Lingual Orthodontists (WSLO).
    He received DDS from Dankook University in South Korea in 1986, MSD and certificate in orthodontics from Dankook University in 1989, and PhD. from Dankook University, 1997.

    At present, He serves as the President of Korean Society of Digital Orthodontists (KSDO) and chief director of his orthodontic exclusive office, Plus 1 Orthodontics in Suwon. He stays in Atlanta, GA, USA as an exchange visiting professor by the invitation of Consortium of Global Education (CGE) in 2020.

The development of mini screw makes it possible to solve various tough tasks in orthodontic treatment. One of these achievements is molar movement which becomes available treatment modality at present orthodontic practice. Now it is time to focus on the outcome stability of molar movement by using mini screw.

For the treatment of anterior spacing, the key to successful and stable treatment is the consideration of strategic approach on target teeth. If the anterior teeth have favorable labio-lingual position and inclination, simple retraction of incisor may cause relapse and result anterior space again after debonding. Mesial movement of molar is more suitable than retraction of anterior teeth in terms of treatment stability. However, misuse of simple protraction force for mesial movement of molar using mini screw can cause labial movement and intrusion of incisor. It is necessary to use careful force mechanism for the molar protraction while maintaining stable incisor position.

In order to prevent inadequate occlusal interdigitation and low stability of the teeth position, the mesial tipping of the molar while protraction should be avoided. How can we prevent mesial tipping of the molar during mesial movement of the molar? Sometimes, asymmetrical mesial movement of molar is required for the correction of unilateral Class II or Class III relationship due to posterior positioned molar. This unilateral movement frequently can cause the rolling of occlusal plane by the intrusion of affected side. To avoid this undesirable side effects and ensure the stability, it is important to maintain tooth axis and vertical position of occlusal plane during protraction. The critical point I suggest is that we have to provide an adequate anchorage support for anterior segment. A specially designed anchorage using mini screw will be effective to solve this kind of problem and contribute to long term stability.

I will describe the possible side effects related to the mesial movement of molar and suggest strategic treatment method to prevent these effects with several clinical cases.