Root resorption, treatment time and extraction rate during orthodontic treatment with self-ligating and conventional brackets

Head Face Med. 2014 Jan 23:10:2. doi: 10.1186/1746-160X-10-2.


Introduction: This study determined the amount and severity of EARR (external apical root resorption) after orthodontic treatment with self-ligating (SL) and conventional (Non-SL) brackets. Differences regarding rate of extraction cases, appointments and treatment time were evaluated.

Material and methods: 213 patients with a mean age of 12.4 ± 2.2 years were evaluated retrospectively. The treatments were performed with SL brackets (n = 139, Smartclip, 3 M Unitek, USA) or Non-SL brackets (n = 74, Victory Series, 3 M Unitek, USA). Measurements of the crown and root length of the incisors were taken using panoramic radiographs. Three-factor analysis of variance (ANOVA) was performed for an appliance effect.

Results: There was no difference between patients treated with Non-SL or SL brackets regarding the amount (in percentage) of EARR (Non-SL: 4.5 ± 6.6 vs. SL: 3.0 ± 5.6). Occurrence of severe EARR (sEARR) did also not differ between the two groups (Non-SL 0.5 vs. SL: 0.3). The percentage of patients with need of tooth extraction for treatment (Non SL: 8.1 vs. SL: 6.9) and the number of appointments (Non-SL: 12.4 ± 3.4 vs. SL: 13.9 ± 3.3) did not show any differences. The treatment time was shorter with Non-SL brackets (Non-SL: 18.1 ± 5.3 vs. SL: 20.7 ± 4.9 months).

Conclusions: This is the largest study showing that there is no difference in the amount of EARR, number of appointments and extraction rate between conventional and self-ligating brackets. For the first time we could demonstrate that occurrence of sEARR does not differ between the two types of brackets.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Child
  • Equipment Design
  • Female
  • Humans
  • Ligation
  • Male
  • Malocclusion / therapy
  • Orthodontic Brackets*
  • Orthodontics, Corrective / instrumentation*
  • Radiography, Panoramic
  • Retrospective Studies
  • Root Resorption* / diagnostic imaging
  • Stress, Mechanical
  • Tooth Apex / diagnostic imaging
  • Tooth Apex / pathology*
  • Tooth Extraction
  • Tooth Movement Techniques / instrumentation