Assessment of the Alignment Acceleration of the Lower Incisors Using a Single Aligner Appliance Modified with Nickel-Titanium Coils: A Randomized Controlled Clinical Trial in Adults.


  • Ziad Mohamad Alhafi
  • Nada Rajeh
  • Zaher Jumaa
  • Zuhir Alasfar



Aligners, Teeth alignment, Dental crowding, Acceleration


OBJECTIVE: The aim of this study was to investigate the effects of a single aligner appliance modified with nickel-titanium coils in accelerating the alignment of crowded lower incisors.

MATERIALS AND METHODS: 36 patients with mild crowding of their lower incisors were randomly divided into two groups: one group received a modified aligner appliance with nickel-titanium coils (Experimental group), while the other group received traditional orthodontic brackets (Control group). The degree of irregularity in the alignment of the incisors was measured every 2 weeks using Little's irregularity index, and this was done at different time points throughout the study: before treatment (T0), after 2 weeks (T1), after 4 weeks (T2), after 6 weeks (T3), after 8 weeks (T4).

RESULTS: A total of 87 patients with anterior mild crowding in the lower dental arch were initially assessed for eligibility. Out of these, 64 patients met the inclusion criteria. Eventually, 36 participants were assigned to receive the treatment. Accordingly, the data from 36 patients were analyzed statistically. There was no significant difference when comparing the two groups at T0, T1, T3, and T4. However, the difference was significant at T2 (p = 0.037). The differences were statistically significant at all time periods within each group (P < 0.001).

CONCLUSION: The use of a modified aligner appliance with nickel-titanium coils effectively treats lower incisors crowding, but it does not accelerate the alignment process compared to the traditional fixed orthodontic appliance.

Author Biographies

Ziad Mohamad Alhafi

Department of Orthodontics, Faculty of Dentistry, Damascus University, Damascus, Syria

Nada Rajeh

Department of Orthodontics, Faculty of Dentistry, Damascus University, Damascus, Syria

Zaher Jumaa

Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Damascus University, Damascus, Syria

Zuhir Alasfar

Department of Periodontology, Faculty of Dentistry, Damascus University, Damascus, Syria


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Adults & the Elderly