Quality of orthodontic treatment with straightwire or standard edgewise appliances

• Register: ISRCTN
• Last refreshed on: 18 June 2018
• Main ID: ISRCTN13048456
• Date of registration: 29/05/2018
• Prospective Registration: No
• Primary sponsor: University of Zurich
• Public title: Quality of orthodontic treatment with straightwire or standard edgewise appliances
• Scientific title: Clinical outcomes of orthodontic extraction treatment with pre-adjusted versus standard edgewise appliances: a retrospective cohort study
• Date of first enrolment: 01/05/2018
• Target sample size: 50
• Recruitment status: Completed
• URL: http://isrctn.com/ISRCTN13048456
• Study type: Observational
• Study design: Retrospective non-randomized comparative multi-center observational cohort study (Treatment)

Countries of recruitment

Norway, Switzerland

Contacts

• Name: Spyridon Papageorgiou

Key inclusion & exclusion criteria

Inclusion criteria: 1. Any ethnicity or race
2. Male or female
3. Class I, Class II, or Class III malocclusion
4. Full complement of teeth excluding the third molars
5. No previous orthodontic treatment
6. No dentofacial deformities or clefts
7. Complete set of diagnostic records

With the following treatment characteristics to control for factors that might influence treatment outcome or duration:
1. One phase treatment with labial fixed appliances in both arches (no two-phase treatment)
2. Bilateral extraction of a premolar in one or two jaws (either 2- or 4-premolars extracted)
3. No temporary anchorage devices of any form
4. No orthognathic surgery
5. No dental trauma
6. No impacted canines
7. Complete set of treatment records
Exclusion criteria: Does not meet inclusion criteria

Age minimum:
Age maximum:
Gender: Both

Health Condition(s) or Problem(s) studied

Most orthodontic malocclusions can be effectively treated with comprehensive fixed appliance treatment, due to the ability of the latter to perform controlled tooth movements in all three planes of space. Often, severe arch length discrepancies or several dental/skeletal malocclusions necessitate the incorporation of dental extractions in the orthodontic treatment plan.
Oral Health

Intervention(s)

Patient clinical documentation is consistently taken by all orthodontists both before insertion of the orthodontic appliances and directly after their removal (around 18-60 months after insertion). This documentation consists of intraoral/extraoral photographs, impressions made with metal trays and alginate to construct dental cast models of the patient’s dentition, and radiographs. These documentation, including each patient’s written log of treatment will be used as material for this study.

Primary Outcome(s)

The ABO OGS score will be evaluated using all its 8 components: alignment, marginal ridges, buccolingual inclination, overjet, occlusal contacts, occlusal relationships, interproximal contacts, and root angulation. This is measured from the patients’ post-treatment documentation (stone cast models of the occlusion and x-ray) using a specific checklist/form provided by ABO. The overall cumulative score for all ABO OGS categories will be used as primary outcome. The principal investigator (S.N.P.) has prior to initiation of the study completed the necessary calibration process as instructed by the ABO. All measurements will be obtained using the special ABO gauge provided with the calibration kit. The principal investigator has extensive experience in cephalometric analyses and their assessment for research purposes. The primary outcome of this study will be the overall ABO OGS score in a continuous scale (expected to be normally-distributed).

Reliability of the method
Descriptive and inferential statistics will be performed to detect both random and systematic errors of the method. Initially, Dahlberg's formula will be used to assess intra examiner repeatability. With the aid of a table of random numbers, 10 patients will be randomly selected and will be re-evaluated 10 days later by the same examiner (S.N.P.) and also by a second examiner. Next, the intraclass correlation coefficient and the Bland-Altman limits of agreement [Bland and Altman, 1986] will be used to evaluate interexaminer agreement.

Secondary Outcome(s)

The secondary outcomes will include each of the separate components of the ABO OGS score that is used as a summary in the primary outcome.

Additionally, the treatment duration will be also extracted from the patient files and be used together with the ABO OGS to assess treatment efficacy. As treatment durations are expected to differ between the two centers, we might consider normalizing treatment durations within each center with the average duration of each center.

Secondary ID(s)

ABOZUROSL

Source(s) of Monetary Support

Universität Zürich

Ethics review

Status:
Approval date:
Contact:

1. Regional Committees for Medical and Health Research Ethics, 26/10/2017, ref: 2017/1885 2. Kantonale Ethikkommission Zürich, ID: 2018-00631 - approval pending

Results

• Results available: Yes
• Date Completed: 01/09/2018