Study design
incisors, orthodontic, trauma
ENDODONTICALLY TREATED TEETH, ROOT RESORPTION, BLIND
This study was a randomized clinical trial with a 1:1:1 allocation ratio. The methods were not changed after trial initiation. The study was approved by the Institutional Review Board at the Jordan University of Science and Technology (approval number 78/117/2018). This trial was registered with ClinicalTrial.gov with identifier number NCT04549948.The sample size was calculated using the G*power 3.1.9 program. Univariate analysis revealed significant variability between subjects (The participants for this study were recruited from patients attending postgraduate orthodontic clinics. All subjects who agreed to participate in the study signed a consent form for participation after clarifying the purpose of the intervention. Subjects were selected based on the inclusion criteria: age ≥ 16 years and ≤ 25 years, normally inclined or retroclined lower incisors, presence of deep bite, depth of COS ≥ 5 mm, non-extraction treatment plan, averaged or reduced lower vertical height, good oral hygiene, and healthy periodontium, and all permanent teeth are present except for the third molars.Exclusion criteria were history of previous orthodontic treatment, teeth with root resorption, endodontically treated teeth, history of previous trauma, restoration on measured teeth, presence of a medical condition or being under medication that could affect the treatment, and smoking.After recruiting patients who met the inclusion criteria and just before the insertion of the leveling AWs, the intervention was randomly allocated using the permuted random block size of 3 with a 1:1:1 allocation ratio by one research assistant (S.D.). The allocation sequence was concealed from the researcher (Y.N.) by sequentially numbered, opaque, sealed, and stapled envelopes before the intervention. Patients were then asked to pick a sealed envelope to assign the method of intervention. The methods were not changed after trial initiation. The patient was blinded to the intervention used, but it was not possible to blind the clinician during treatment. However, the measurements of the BF were performed by one research assistant (H.D.) who was blinded to the type of intervention used.