## Protocol Section
### Identification Module
**NCT ID:** NCT04389879

**Acronym:** Retention

**Brief Title:** CAD/CAM Fixed Retainers vs. Conventional Multistranded Fixed Retainers in Orthodontic Patients. Comparison of Stability, Retainer Failure Rate, Adverse Effects, Cost-effectiveness, and Patient Satisfaction. A Randomized Controlled Clinical Trial

**Official Title:** CAD/CAM Fixed Retainers vs. Conventional Multistranded Fixed Retainers in Orthodontic Patients. Comparison of Stability, Retainer Failure Rate, Adverse Effects, Cost-effectiveness, and Patient Satisfaction. A Randomized Controlled Clinical Trial.

#### Organization Study ID Info
**ID:** 01286
#### Organization
**Class:** OTHER
**Full Name:** University of Aarhus
### Status Module
#### Completion Date
**Date:** 2025-12

**Type:** ESTIMATED

#### Expanded Access Info
#### Last Update Post Date
**Date:** 2022-11-03

**Type:** ACTUAL

**Last Update Submit Date:** 2022-11-02

**Overall Status:** ACTIVE_NOT_RECRUITING

#### Primary Completion Date
**Date:** 2025-11

**Type:** ESTIMATED

#### Start Date
**Date:** 2018-09-01

**Type:** ACTUAL

**Status Verified Date:** 2022-11

#### Study First Post Date
**Date:** 2020-05-15
**Type:** ACTUAL
**Study First Submit Date:** 2020-04-16
**Study First Submit QC Date:** 2020-05-11
### Sponsor Collaborators Module

#### Collaborators

**Class:** OTHER

**Name:** University of Oslo

#### Lead Sponsor

**Class:** OTHER

**Name:** University of Aarhus

#### Responsible Party

**Type:** SPONSOR

### Oversight Module

**Is FDA Regulated Device:** False

**Is FDA Regulated Drug:** False

**Oversight Has DMC:** True

### Description Module

**Brief Summary:** Introduction:

Orthodontic retainers are used after the completion of orthodontic treatment to assure dental occlusal stability and to maintain the achieved end-result. However, without retention teeth could go back to their initial dental malposition or could even take a different unpredicted position resulting once again in dental malocclusion (a deviation from normal occlusion).

There are different types of retainers, some are fixed (glued to the back of the front teeth), and others are removable (can be removed and replaced into the mouth by the patient).

While there are various retainers used for retention (stability), there is no perfect method. Fixed retainers (FRs) are used worldwide. On the one hand, FRs focus on preventing relapse. On the other hand, there are sometimes some adverse effects of retainers; they could fail at a certain point (break/get loose), or cause unwanted tooth movements. Until now, the choice of a retention method is based solely on clinicians' experience as there is no substantial evidence regarding the best retention method or the duration of the retention period. Some clinicians prolong the retention period while others prefer to keep the retainers for an indefinite time.

As the world is advancing, so is the orthodontic science. New FR fabricated by CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing), are assumed to have greater accuracy, better fit, and most importantly, might offer a passive positioning of the retainer. However, the evidence about CAD/CAM FRs is very limited.

Purpose:

To investigate and compare the clinical effectiveness of two types of FRs; CAD/CAM vs. multistranded wire, in terms of stability (primary outcome), failure rate, adverse effects, cost-effectiveness, and patient satisfaction (secondary outcomes), substantial up to 5 years after retainer placement.

Hypotheses:

Compared to traditional multistranded FRs, CAD/CAM FRs have:

* Better long term stability,
* Similar failure rate,
* Fewer adverse effects,
* Similar cost-effectiveness and patient satisfaction.

**Detailed Description:** Material and Methods

Setting: Section of Orthodontics, Department of Dentistry and Oral Health, Aarhus University, Denmark and Department of Orthodontics, Faculty of Dentistry, University of Oslo, Norway.

Sample size: 126 participants are needed for this study.

Randomization: After oral and written consent is obtained, allocation to groups, either conventional multistranded Stainless Steel fixed retainers, or CAD/CAM custom-cut Nickel Titanium fixed retainers, will take place at the last appointment before debonding. Subjects will be allocated 1:1 into one of the two groups.

Intervention protocol: After completing a full active orthodontic treatment, at both centers. The achieved treatment end result has to be maintained in the long term in order to prevent relapse (movement of teeth to the initial malocclusion). One of either two different fixed retainers will be bonded (to the upper and lower anterior teeth) by one operator in each center.

This study follows a standard retention protocol procedure carried at both centers and has a long term posttreatment follow-up of 5 years. Patients will be recalled for follow-up appointments after 1, 3, 6, 12, 24, 36 and 60 months. At follow-up visits, we will perform the following: at 1, and 3 months - a clinical examination. At 6, 12, 24, 36, and 60 months - a clinical examination, a digital impression of the teeth known as "an intraoral scan" (Trios 3, 3Shape, Copenhagen, Denmark) and intraoral photographs. In addition, at 1, 6, and 12 months patients will be asked to fill out a Visual Analogue Scale (VAS) form regarding patient satisfaction Furthermore, we will investigate stability by superimposition (Orthoanalyzer, 3Shape, Copenhagen, Denmark) together with recording of adverse effects (i.e. any changes in torque and/or rotations of the teeth).

### Conditions Module

**Conditions:**

- Relapse

**Keywords:**

- Orthodontic retainer

- relapse

- stability

- CAD/CAM

- fixed retainer

### Design Module

#### Design Info

**Allocation:** RANDOMIZED

**Intervention Model:** PARALLEL

**Intervention Model Description:** Two-center randomized controlled clinical trial. Consecutive patients who are about to finish their fixed appliance orthodontic treatment at the two orthodontic departments will be screened for eligibility criteria. Eligible subjects will be randomized to have one of either two different fixed retainers to be bonded (to the upper and lower anterior teeth) by one operator in each center.

Subjects will be allocated 1:1 into one of the two groups.

##### Masking Info

**Masking:** NONE

**Masking Description:** The outcome assessor will be blinded only to the patient satisfaction and cost-effectiveness outcomes.

**Primary Purpose:** OTHER

#### Enrollment Info

**Count:** 126

**Type:** ESTIMATED

**Phases:**

- NA

**Study Type:** INTERVENTIONAL

### Arms Interventions Module

#### Arm Group 1

**Description:** CAD/CAM custom-cut Nickel Titanium (NiTi) FR

**Intervention Names:**

- Other: Bonding of either CAD/CAM or conventional multistranded stainless steel fixed retainer

**Label:** CAD/CAM

**Type:** EXPERIMENTAL

#### Arm Group 2

**Description:** Conventional multistranded Stainless Steel (SS) FR

**Intervention Names:**

- Other: Bonding of either CAD/CAM or conventional multistranded stainless steel fixed retainer

**Label:** Conventional multistranded

**Type:** ACTIVE_COMPARATOR

### Interventions

#### Intervention 1

**Arm Group Labels:**

- CAD/CAM

- Conventional multistranded

**Description:** Investigate and compare the clinical effectiveness of two types of fixed retainers; CAD/CAM vs. multistranded wire.

**Name:** Bonding of either CAD/CAM or conventional multistranded stainless steel fixed retainer

**Type:** OTHER

### Outcomes Module

#### Primary Outcomes

**Description:** Change in lower incisor crowding will be assessed using Little's Irregularity Index (LII). Change in overall occlusal stability will be assessed by the Peer Assessment Rating (PAR) index. In addition, changes in arch dimensions, occlusal relationships, and re-opening of extraction spaces will be recorded.

**Measure:** Stability

**Time Frame:** From debonding (T1), and after 6, 12, 24, 36 and 60 months in retention phase (T4, T5, T6, T7, and T8 respectively)

#### Secondary Outcomes

**Description:** Calculated from the first day of retainer's bonding to the day of the first failure episode

**Measure:** Failure rate and survival time

**Time Frame:** From the time of retainer bonding to the first failure episode: From debonding, and up to 60 months later

**Description:** Screen for unexpected posttreatment changes in the mandibular anterior region associated with the use of both types of fixed retainers

**Measure:** Adverse effects

**Time Frame:** From debonding, and up to 60 months later

**Description:** Unit costs in euros (€) will be used to value the resources included

**Measure:** Cost-effectiveness

**Time Frame:** From debonding, and up to 60 months later

**Description:** Visual Analogue Scale (VAS)

**Measure:** Patient satisfaction

**Time Frame:** From debonding, and after 1, 6 and 12 months in retention phase

### Eligibility Module

**Eligibility Criteria:** Inclusion Criteria:

1. Healthy patients.
2. Age: 12-25 years old (at time of debonding).
3. Presence of all maxillary and mandibular anterior teeth, with normal shape and size.
4. Completion of a course of fixed appliance therapy involving both dental arches.
5. Subjects willing to consent to the trial and comply with the trial regime.

No restriction to presenting initial malocclusion, type of active orthodontic treatment undertaken provided that it included full fixed appliances (functional/removable appliances in combination with fixed appliances - extraction or non-extraction)

Exclusion Criteria:

1. Patients with cleft lip or palate, or both or any other craniofacial syndrome.
2. Patients who had surgical correction of the jaws: Le fort I (2- or 3-piece maxilla) or SARPE (surgically assisted rapid palatal expansion).
3. Lingual appliance treatments.
4. Periodontal disease.
5. Hypoplasia of enamel.
6. Fluorosis.
7. Active caries, restorations or fractures in the anterior teeth.
8. Patients who have had separate debonding appointments for each jaw, with a difference of more than 2 months in between.
9. Re-treated patients.

**Healthy Volunteers:** True

**Maximum Age:** 25 Years

**Minimum Age:** 12 Years

**Sex:** ALL

**Standard Ages:**

- CHILD

- ADULT

### Contacts Locations Module

#### Locations

**Location 1:**

**City:** Aarhus

**Country:** Denmark

**Facility:** Marie Anne Michele Cornelis

**Zip:** 8000

**Location 2:**

**City:** Oslo

**Country:** Norway

**Facility:** University of Oslo

**Zip:** 0455

#### Overall Officials

**Official 1:**

**Affiliation:** University of Aarhus

**Name:** Marie A Cornelis

**Role:** PRINCIPAL_INVESTIGATOR

### IPD Sharing Statement Module

**IPD Sharing:** NO

### References Module

#### References

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**PMID:** 2591482

**Citation:** Al Yami EA, Kuijpers-Jagtman AM, van 't Hof MA. Stability of orthodontic treatment outcome: follow-up until 10 years postretention. Am J Orthod Dentofacial Orthop. 1999 Mar;115(3):300-4. doi: 10.1016/s0889-5406(99)70333-1.

**PMID:** 10066979

**Citation:** Littlewood SJ, Millett DT, Doubleday B, Bearn DR, Worthington HV. Retention procedures for stabilising tooth position after treatment with orthodontic braces. Cochrane Database Syst Rev. 2004;(1):CD002283. doi: 10.1002/14651858.CD002283.pub2.

**PMID:** 14973985

**Citation:** Reitan K. Clinical and histologic observations on tooth movement during and after orthodontic treatment. Am J Orthod. 1967 Oct;53(10):721-45. doi: 10.1016/0002-9416(67)90118-2. No abstract available.

**PMID:** 5233926

**Citation:** Little RM, Wallen TR, Riedel RA. Stability and relapse of mandibular anterior alignment-first premolar extraction cases treated by traditional edgewise orthodontics. Am J Orthod. 1981 Oct;80(4):349-65. doi: 10.1016/0002-9416(81)90171-8.

**PMID:** 6945805

**Citation:** Littlewood SJ, Millett DT, Doubleday B, Bearn DR, Worthington HV. Orthodontic retention: a systematic review. J Orthod. 2006 Sep;33(3):205-12. doi: 10.1179/146531205225021624.

**PMID:** 16926314

**Citation:** Gardner SD, Chaconas SJ. Posttreatment and postretention changes following orthodontic therapy. Angle Orthod. 1976 Apr;46(2):151-61. doi: 10.1043/0003-3219(1976)0462.0.CO;2.

**PMID:** 1064343

**Citation:** Goldberg AI, Behrents RG, Oliver DR, Buschang PH. Facial divergence and mandibular crowding in treated subjects. Angle Orthod. 2013 May;83(3):381-8. doi: 10.2319/061912-505.1. Epub 2012 Oct 18.

**PMID:** 23075061

**Citation:** Artun J, Spadafora AT, Shapiro PA. A 3-year follow-up study of various types of orthodontic canine-to-canine retainers. Eur J Orthod. 1997 Oct;19(5):501-9. doi: 10.1093/ejo/19.5.501.

**PMID:** 9386336

**Citation:** Bolla E, Cozzani M, Doldo T, Fontana M. Failure evaluation after a 6-year retention period: a comparison between glass fiber-reinforced (GFR) and multistranded bonded retainers. Int Orthod. 2012 Mar;10(1):16-28. doi: 10.1016/j.ortho.2011.12.005. Epub 2012 Jan 11. English, French.

**PMID:** 22240271

**Citation:** Rose E, Frucht S, Jonas IE. Clinical comparison of a multistranded wire and a direct-bonded polyethylene ribbon-reinforced resin composite used for lingual retention. Quintessence Int. 2002 Sep;33(8):579-83.

**PMID:** 12238688

**Citation:** Salehi P, Zarif Najafi H, Roeinpeikar SM. Comparison of survival time between two types of orthodontic fixed retainer: a prospective randomized clinical trial. Prog Orthod. 2013 Sep 11;14:25. doi: 10.1186/2196-1042-14-25.

**PMID:** 24326013

**Citation:** Saleh M, Hajeer MY, Muessig D. Acceptability comparison between Hawley retainers and vacuum-formed retainers in orthodontic adult patients: a single-centre, randomized controlled trial. Eur J Orthod. 2017 Aug 1;39(4):453-461. doi: 10.1093/ejo/cjx024.

**PMID:** 28430890

**Citation:** Hichens L, Rowland H, Williams A, Hollinghurst S, Ewings P, Clark S, Ireland A, Sandy J. Cost-effectiveness and patient satisfaction: Hawley and vacuum-formed retainers. Eur J Orthod. 2007 Aug;29(4):372-8. doi: 10.1093/ejo/cjm039.

**PMID:** 17702797

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**PMID:** 24084630

**Citation:** Forde K, Storey M, Littlewood SJ, Scott P, Luther F, Kang J. Bonded versus vacuum-formed retainers: a randomized controlled trial. Part 1: stability, retainer survival, and patient satisfaction outcomes after 12 months. Eur J Orthod. 2018 Jul 27;40(4):387-398. doi: 10.1093/ejo/cjx058.

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**Citation:** Wolf M, Schumacher P, Jager F, Wego J, Fritz U, Korbmacher-Steiner H, Jager A, Schauseil M. Novel lingual retainer created using CAD/CAM technology: evaluation of its positioning accuracy. J Orofac Orthop. 2015 Mar;76(2):164-74. doi: 10.1007/s00056-014-0279-8. English, German.

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## Derived Section

### Condition Browse Module - Ancestors

- ID: D000020969

- Term: Disease Attributes

- ID: D000010335

- Term: Pathologic Processes

### Condition Browse Module - Browse Branches

- Abbrev: BC23

- Name: Symptoms and General Pathology

- Abbrev: All

- Name: All Conditions

### Condition Browse Module - Browse Leaves

- ID: M14850

- Name: Recurrence

- Relevance: HIGH

- As Found: Relapse

- ID: M22700

- Name: Disease Attributes

- Relevance: LOW

- As Found: Unknown

### Condition Browse Module - Meshes

- ID: D000012008

- Term: Recurrence

### Intervention Browse Module - Browse Branches

- Abbrev: Micro

- Name: Micronutrients

- Abbrev: All

- Name: All Drugs and Chemicals

### Intervention Browse Module - Browse Leaves

- ID: M12472

- Name: Nickel

- Relevance: LOW

- As Found: Unknown

### Misc Info Module

- Version Holder: 2024-05-24
