Self-ligating vs. Conventional ligating orthodontic bracket systems (smile aesthetics perspective)
: Data from randomised clinical trials

  • Abdulghani Mustafa S. Alarabi

Student thesis: Doctoral ThesisDoctor of Philosophy


Introduction: Today one of the primary goals of any kind of dental treatment is the achievement of balanced smile aesthetics, as patients increasingly attend dental clinics to improve their appearance. The main aim of the present study was to assess and compare the smile aesthetics created by the use of two orthodontic bracket systems (self-ligating vs. conventional ligating) as a part of analysing secondary outcomes of two randomised clinical trials comparing between these two systems.

Methodology: The assessment of smile aesthetics was done by analysing and scoring post-orthodontic treatment 125 frontal smile photographs subjectively and objectively. The subjective evaluation was performed by 20 dental professionals and 20 laypeople, while the objective assessment was done by one principal examiner using a group of smile aesthetics parameters.

Statistical analysis: Multiple regression statistical analyses were performed to test the association between subjective and objective assessment of smile aesthetics in order to find the significant smile aesthetics predictors and assess the effect of the bracket type (self-ligating vs conventional) on the resulting smile aesthetics.

Results: The finding from this research shows that the bracket type was not an important smile aesthetics factor in all the statistical models, although there are other important smile aesthetics factors as there was a significant correlation between the subjective and objective assessment of smile aesthetics parameters (Pearson’s correlation coefficients “r” > 0.50).

Conclusion: There is insufficient evidence to reject the null hypotheses of no significant difference in the smile aesthetics created by the two orthodontic bracket systems. An Orthodontic Smile Aesthetics Rating (OSAR) tool has been developed.
Date of Award2018
Original languageEnglish
SponsorsUniversity of Tripoli
SupervisorDavid Bearn (Supervisor) & Peter Mossey (Supervisor)


  • Smile aesthetics
  • Self-ligating orthodontic brackets
  • Conventional ligation orthodontic brackets
  • OSAR
  • Dental midline
  • Facial midline
  • Overview of systematic reviews
  • systematic review
  • Meta-analysis
  • Multiple regression
  • Smile analysis
  • Smile assessment

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