The Effectiveness of 3 Orthodontic Fixed Retention Schemes on Post-treatment Stability and Gingival Recession

Study Overview
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Brief Summary
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There is high possibility of relapse of the lower anterior teeth after orthodontic treatment. Relapse is related with the initial orthodontic anomaly, pathology of surrounding tissues, patient's age and sex and compliance and the retention protocol applied. The options for the later are various. Permanent fixed retainers are considered of the most common ones and vastly vary based of composition. There are fixed retainers distinguished for their composition (SS, β-NiTi, fiber-reinforced composite retainers) or for their shape and dimensions (round or rectangular shape and single-strand or multi-strand respectively), and/or for the teeth they are placed on (canine and canine or canine to canine). Fixed retainers may require patient's cooperation , nevertheless debond failure rate varies between 0.1-53%. The aim of this prospective randomized clinical study is to compare failure incidents and retention effect on lower anterior teeth after orthodontic finish between three different types of fixed retainers. There will be 3 arms studied in this research: a) single strand 0.016x0.022'' β-Ti canine to canine, b) 0.028'' SS canine to canine and c) 0.027'' multi-strand twistflex canine to canine. Variables such as repeatability of failures, and undesired tooth movements will be measured. Measurements will be repeated every 3 months after patient's recruitment in this study, for one year period (12 months in total). Intraoral scans will be collected during baseline (fixed retainer insertion) and after 12 months.

Official Title
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A Single-center, 3-arm, Parallel-group Randomized Controlled Trial to Evaluate Bond Failures and the Effectiveness of Three Orthodontic Retention Schemes in Preventing Post-treatment Mandibular Arch Changes

Conditions
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Relapse, Orthodontic Retention

Intervention / Treatment
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* Device: Experimental: Single strand β-Ti fixed retainer
* Device: Experimental: SS fixed retainer
* Device: Experimental: Twisted fixed retainer


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients treated with fixed orthodontic appliances (Roth 0.018'' slot at their final finishing stage) Patients with fixed orthodontic appliances at least between their lower first premolars No lower anterior teeth crowding (total irregularity index score = 0) Patients with no need of removable retention appliances on their lower teeth Exclusion Criteria: Active caries on adjacent or lingual surfaces of lower anterior teeth Active periodontitis Supragingival calculus Gum bleeding during bonding of fixed retainer Gingival pocket depth greater than 3mm Syndromes or other anomalies of the craniofacial complex or other mental illness Missing or impacted teeth or other dental anomalies Congenital anomalies/syndromes Allergies regarding the alloys of fixed retainers Need for chemoprevention before data collection of periodontal indexes Diabetes Smoking Usage of antibiotics Pregnancy Participation in other clinical trials

Ages Eligible for Study
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Minimum Age: 13 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Single strand β-Ti fixed retainer<br>Single strand β-Ti fixed retainer 0.011in diameter, bonded on each tooth separately from #33-43 | Device: Experimental: Single strand β-Ti fixed retainer<br>* All 90 patients between 13-30 y.o. treated with fixed orthodontic appliances (Roth 0.018'' slot at their final finishing stage) on at least between their lower first premolars and with no lower anterior teeth crowding (total irregularity index score = 0) and no need of removable retention appliances on their lower teeth, were randomly assigned to one of the three experimental groups.<br>|
| Experimental: SS fixed retainer<br>SS fixed retainer 0.028in diameter, bonded on each tooth separately from #33-43 | Device: Experimental: SS fixed retainer<br>* All 90 patients between 13-30 y.o. treated with fixed orthodontic appliances (Roth 0.018'' slot at their final finishing stage) on at least between their lower first premolars and with no lower anterior teeth crowding (total irregularity index score = 0) and no need of removable retention appliances on their lower teeth, were randomly assigned to one of the three experimental groups.<br>|
| Experimental: Twisted fixed retainer<br>Twisted fixed retainer 0.027in diameter, bonded on each tooth separately from #33-43 | Device: Experimental: Twisted fixed retainer<br>* All 90 patients between 13-30 y.o. treated with fixed orthodontic appliances (Roth 0.018'' slot at their final finishing stage) on at least between their lower first premolars and with no lower anterior teeth crowding (total irregularity index score = 0) and no need of removable retention appliances on their lower teeth, were randomly assigned to one of the three experimental groups.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of teeth that failed regarding the bonding strength |  | baseline-3 months | 
| Number of teeth that failed regarding the bonding strength |  | 3 months-6 months | 
| Number of teeth that failed regarding the bonding strength |  | 6 months-9 months | 
| Number of teeth that failed regarding the bonding strength |  | 9 months-1 year | 
| Repeatability of bonding strength failure per patient and per tooth |  | baseline-3 months | 
| Repeatability of bonding strength failure per patient and per tooth |  | 3 months-6 months | 
| Repeatability of bonding strength failure per patient and per tooth |  | 6 months-9months | 
| Repeatability of bonding strength failure per patient and per tooth |  | 9months-1 year | 
| Breakage of fixed retainer wires |  | baseline-3 months | 
| Breakage of fixed retainer wires |  | 3 months-6 months | 
| Breakage of fixed retainer wires |  | 6 months-9 months | 
| Breakage of fixed retainer wires |  | 9 months-1 year | 
| Space discrepancy (Little index)(in mm) |  | baseline-3 months | 
| Space discrepancy (Little index)(in mm) |  | 3 months-6 months | 
| Space discrepancy (Little index)(in mm) |  | 6 months-9 months | 
| Space discrepancy (Little index)(in mm) |  | 9 months-1 year | 
| Mandibular intercanine distance |  | baseline-3 months | 
| Mandibular intercanine distance |  | 3 months-6 months | 
| Mandibular intercanine distance |  | 6 months-9 months | 
| Mandibular arch length (in mm) |  | 9 months-1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tooth rotations in lower anterior teeth |  | baseline-3 months | 
| Tooth rotations in lower anterior teeth |  | 3 months-6 months | 
| Tooth rotations in lower anterior teeth |  | 6 months-9 months | 
| Tooth rotations in lower anterior teeth |  | 9 months-1 year | 
| Extrusion in lower anterior teeth |  | baseline-3 months | 
| Extrusion in lower anterior teeth |  | 3 months-6 months | 
| Extrusion in lower anterior teeth |  | 6 months-9 months | 
| Extrusion in lower anterior teeth |  | 9 months-1 year | 
| Tip inclinations anteroposteriorly |  | baseline-3 months | 
| Tip inclinations anteroposteriorly |  | 3 months-6 months | 
| Tip inclinations anteroposteriorly |  | 6 months-9 months | 
| Tip inclinations anteroposteriorly |  | 9 months -1 year |