Thursday, 2 June 2011

Root Resorption
Apical root resorption (ARR) is a common idiopathic problem associated with orthodontic
treatment. According to Reitan and Rygh no orthodontic tooth movement is possible without root
resorption. Fortunately, in most cases root resorption will be minor and therefore of no clinical
importance. However, moderate to severe root resorption has been reported to occur with a
frequency of 10-20 percent. Extreme root resorption (> 1/3 of the original root length) is very rare.
Several causes have been mentioned to be a factor determining resorption like biological and
mechanical factors. The purpose of this study was to investigate whether patients treated with the
Tip-Edge © appliance resulted in more ARR of the central and lateral incisors during the torquing
(3 rd stage) than the non-torquing phases (first two stages) of orthodontic treatment. The three
stages of this orthodontic technique make it possible to examine the amount of root shortening
during torque separately from the other types of tooth movement. The ARR ratio was calculated
in 31 patients (20 females and 11 males) after the non-torquing stage of treatment and after the
torquing phase by analysing peri-apical radiographs that were taken at the beginning of treatment
(T1), before the start of the torquing stage (T2) and at the end of treatment (T3). Root shortening
after orthodontic treatment was seen for 70 percent of the central and 76 percent of the lateral
incisors. After the non-torquing stage 48 percent and 53 percent of the central and lateral incisors
respectively showed already ARR. Compared with the non-torquing stage of treatment, 38
percent of the central incisors and 55 percent of the lateral incisors showed ARR during the
application of torque while 22 percent of the central and lateral incisors showed only apical root
resorption during the torquing phase. The mean ARR ratio for central and lateral incisors was the
same after the non-torquing stage of treatment, but was significantly different from a tooth with no
root resorption. After the torquing stage, the ARR ratio for the central incisors was 0.96 and for
lateral incisors 0.92. At the end of treatment the ratio was 0.89 and 0.85 respectively. This study
revealed that both the central and the lateral incisors showed comparable amounts of ARR during
the torquing and non-torquing stage of Tip-Edge treatment.
Prof. Dr. Guy de Pauw
Name: DE PAUW
First names: Guy, Arthur, Madeleine
Place & date of birth: Aalst (Belgium), May 17 th , 1962.
Academic degrees
- Dental Sciences: 1980-1985, R.U. Ghent
- Specialist in Orthodontics and Dentofacial Orthopaedics : 1985-1989, R.U.
Ghent
- Specialist in Orthodontics and Dentofacial Orthopaedics: 1994, Register of
Specialists, The Netherlands.
- PhD, University of Ghent: “Orthopaedic displacement of the maxilla”, October 10 th , 2002.
Functions at the University
1989: Full time staff member at the orthodontic department (organisation of the department,
clinical supervisor, teacher, researcher)
1993-1994: Part time (7/10) staff member
1995-2006: Part time (5/10) staff member
2006 - : Full professor and chairman of the Orthodontic Department
2006 - : Coordinator Centre of Congenital Facial Anomalies
2007 - : Dean Dental School
2007 - : Coordinator of Orthodontic Master after Master Postgraduate Programme
2008 - : Member of the Faculty of Medicine
2009- : Member of the sectorraad
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