Survival Rate of Two Types of Multistranded Fixed Retainers (Surv_Retain)

Survival Rate of Two Types of Multistranded Fixed Retainers: A Randomized Controlled Clinical Trial

1. Why is this study being done? After orthodontic treatment (such as braces), teeth can move back toward their original positions. To prevent this, orthodontists use retainers during the retention phase of treatment. One common option is a fixed retainer, which is a thin wire bonded to the inside surfaces of the front teeth. Fixed retainers help keep teeth in their corrected positions for many years. There are different types of fixed retainers, and they differ in how the wire is made. However, it is still unclear which type works best and lasts the longest. Some retainers may break, come loose, or make oral hygiene more difficult.

   This study aims to compare two commonly used types of fixed retainers to determine which one performs better over time.

2. What is the purpose of the study?

   The main goal of this study is to find out whether the type of fixed orthodontic retainer affects how long it remains intact and functional after orthodontic treatment. The study will also evaluate whether the type of retainer influences:

   - patient comfort and satisfaction

   - ease of maintaining oral hygiene

   • gum and periodontal health
   • stability of tooth alignment after treatment.

3. Who can participate?

   People may be eligible to participate if they:

   - are 15-50 years old

   - have completed orthodontic treatment

   • have all lower front teeth present
   • have healthy gums and teeth in the lower front area. Some patients will not be eligible if they have active gum disease or need additional dental treatment in the lower front teeth.
4. What will happen during the study? Participants who agree to take part will be randomly assigned to receive one of two types of fixed retainers. Random assignment means that a computer will decide which retainer each participant receives, similar to drawing lots.

The two types of retainers being compared are:

1. Round twisted wire retainer (3-strand stainless steel wire)

2. Braided rectangular wire retainer (8-strand braided wire) Both types are commonly used in orthodontic practice. 5) What will participants need to do? At the start of the study, the orthodontic appliance (braces) will be removed and the retainer will be bonded to the lower front teeth.

   Participants will attend follow-up visits over two years:

   • at the start of the study
   • after 3, 6,12, 18, and 24 months.

   During these visits, the research team will:

   - check whether the retainer is still intact

   - examine gum health

   • take dental impressions and photographs

   • ask participants to complete a short questionnaire about comfort and oral hygiene.

     6) What are the possible risks?

   The study procedures are the same as those commonly used in routine orthodontic care. Possible minor discomforts may include:

   - mild discomfort during gum examination

   - temporary discomfort when dental impressions are taken. No additional invasive procedures are planned. 7) Are there any benefits?

   Participants may benefit from:

   - regular monitoring of their retainer

   • routine evaluation of gum health

   • early detection of any problems with the retainer. The results of this study may help orthodontists choose the most reliable retainer for future patients.

     8) Is participation voluntary? Yes. Taking part in the study is completely voluntary. Participants may withdraw from the study at any time without affecting their orthodontic care. Personal information will be kept confidential and securely stored.

Study Overview

• Status: Active, not recruiting
• Conditions: Orthodontic Retention
• Intervention / Treatment: Device: Placement of round twisted retainer wire; Device: Placement of rectangular braided retainer wire

Detailed Description

Orthodontic treatment is typically followed by a retention phase aimed at maintaining the alignment achieved during active treatment. Without adequate retention, teeth may gradually return toward their original positions, a phenomenon known as orthodontic relapse. Fixed retainers bonded to the lingual surfaces of the mandibular anterior teeth are widely used because they provide continuous stabilization without relying on patient compliance.

Several designs of multistranded stainless steel fixed retainers are available, differing in wire configuration, number of strands, cross-sectional shape, and mechanical properties. Despite their widespread use, there is limited clinical evidence comparing the long-term performance of different retainer designs. Existing reports indicate that failures of fixed retainers-such as wire fracture or detachment from the tooth surface-occur relatively frequently, particularly during the early months after placement. Failure rates of approximately 40-50% within two years have been reported for some retainer types, depending on materials and bonding protocols.

Traditional retainers made of twisted round multistranded stainless steel wire are commonly used in orthodontic practice. However, these retainers may occasionally unravel or deform, which can lead to unwanted tooth movement. Compressed braided retainers with a rectangular cross-section have been proposed as an alternative design that may offer improved mechanical stability and potentially reduce the risk of such complications. Comparative clinical data evaluating the performance of these two retainer types remain limited.

This study is designed as a prospective randomized controlled clinical trial with two parallel treatment groups. Participants completing orthodontic treatment and meeting eligibility criteria will be randomly assigned in a 1:1 ratio to receive either a three-stranded twisted round stainless steel retainer or an eight-stranded compressed braided rectangular retainer bonded to the mandibular anterior teeth. Randomization will be performed using a computer-generated sequence with permuted blocks to maintain balanced group sizes during recruitment. Allocation concealment will be ensured through the use of sequentially numbered, opaque, sealed envelopes opened after participant enrollment.

Blinding of clinicians and participants is not feasible because the structural characteristics of the retainers differ visibly. To minimize bias, standardized clinical procedures will be used for retainer placement and follow-up examinations, and predefined objective criteria will be applied to identify retainer failure events. Data analysis will be performed using coded group labels so that the statistician remains independent from the clinical procedures.

Participants will be monitored for a period of 24 months following retainer placement. During scheduled follow-up visits, the integrity of the retainer will be evaluated, and additional clinical examinations will be conducted to document oral health parameters and stability of tooth alignment. Patient-reported information will also be collected using structured questionnaires addressing comfort, satisfaction, and perceived oral hygiene difficulties associated with the retainers.

The results of this trial are expected to provide clinically relevant evidence regarding the comparative durability and clinical performance of two commonly used multistranded orthodontic retainers. Improved understanding of retainer survival and associated clinical outcomes may contribute to optimizing retention protocols and enhancing long-term stability following orthodontic treatment.

• Study Type: Interventional
• Enrollment (Actual): 133
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 15-50 years of age at debonding,
• all mandibular permanent incisors and canines present,
• no active caries, no restorations, no fractures on the mandibular incisors and canines,
• no periodontal disease;
• retention plan including only retainer bonded from 3 to 3

Exclusion Criteria:

• inadequate hygiene,
• need for restorative or surgical treatment,
• active periodontal disease,
• removable retainer as adjunct to a bonded retainer

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Round twisted wire; Patients are privided with 0.0215-inch stainless steel three-strand round twisted wire retainer (Ortho Organizers, Lindenberg, Germany)	Device: Placement of round twisted retainer wire; Participants assigned to this intervention will receive a fixed mandibular lingual retainer made of a three-stranded twisted round stainless steel wire (diameter 0.0215 inches). After completion of active orthodontic treatment and removal of the fixed appliance, the retainer wire will be adapted to the lingual surfaces of the mandibular anterior teeth (canine to canine). The wire will then be bonded to each tooth using a standard orthodontic adhesive technique to provide continuous stabilization of tooth alignment during the retention phase. Prior to retainer placement, professional dental cleaning (scaling and air polishing) will be performed. The retainer will be bonded according to a standardized clinical protocol used in the study site. After placement, the integrity of the retainer will be monitored during scheduled follow-up visits to detect possible failures such as wire fracture or debonding.
Active Comparator: Rectangular braided wire; Patients are privided with 0.0265 inch × 0.0106 inch eight-strand Bond-a-Braid wire retainer (Reliance Orthodontic Products, Itasca, IL, USA)	Device: Placement of rectangular braided retainer wire; Participants assigned to this intervention will receive a fixed mandibular lingual retainer made of an eight-stranded compressed braided stainless steel wire with a rectangular cross-section (0.008 × 0.03 inches) (Bond-a-Braid Lingual Retainer, HG Orthodontics). After completion of active orthodontic treatment and removal of the fixed orthodontic appliance, the retainer wire will be adapted to the lingual surfaces of the mandibular anterior teeth (canine to canine). The wire will be bonded to each tooth using a standard orthodontic adhesive technique to maintain tooth alignment during the retention phase. Before retainer placement, professional dental cleaning (scaling and air polishing) will be performed. The retainer will be bonded following a standardized clinical protocol applied to all participants in the study. After placement, the integrity and performance of the retainer will be evaluated during scheduled follow-up visits to identify potential failures such as debonding or wir

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Survival rate	The survival rate of the fixed mandibular anterior retainer will be defined as the proportion of retainers that remain intact and functional without failure during the follow-up period. Retainer failure will be recorded when any of the following events occurs: (1) debonding of the retainer from one or more teeth, (2) fracture of the retainer wire, (3) simultaneous fracture and debonding, or (4) complete loss of the retainer. Retainer integrity will be assessed during scheduled clinical examinations, and the date and type of failure will be documented when detected.	Up to 24 months after retainer placement (assessed at baseline, 3, 6, 12, 18, and 24 months).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Patient comfort and satisfaction	Patient-reported outcomes will be assessed using a structured questionnaire evaluating comfort, overall satisfaction with the fixed retainer, and perceived difficulties with oral hygiene. Participants will rate factors such as irritation or discomfort caused by the retainer, interference with daily activities (e.g., speaking or eating), overall satisfaction with the retainer, and the perceived difficulty of maintaining oral hygiene (e.g., brushing or flossing around the retainer). Responses will be recorded using a standardized rating scale, and higher scores will indicate greater levels of the measured construct (e.g., higher comfort or greater difficulty, depending on the item). The questionnaire will be completed by participants at each scheduled follow-up visit	Assessed at baseline (retainer placement) and during follow-up visits at 3, 6, 12, 18, and 24 months after retainer placement.
Periodontal health - Periodontal Index	Periodontal status assessed using the Russell Periodontal Index, which evaluates gingival inflammation and periodontal destruction. The index is calculated based on clinical examination of each tooth and reflects the severity of periodontal disease. Unit of Measure: Index score (0-8)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Periodontal health - Bleeding on Probing (BoP)	Assessment of gingival bleeding following gentle periodontal probing at the gingival sulcus. Bleeding presence is used as an indicator of gingival inflammation. Unit of Measure: Presence of bleeding (yes/no) or percentage of sites with bleeding (%)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Periodontal health - Plaque Index	Dental plaque accumulation assessed using the Silness and Löe Plaque Index, which evaluates plaque thickness at the gingival margin on selected tooth surfaces. Unit of Measure: Index score (0-3)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Periodontal health - Gingival Index	Gingival inflammation assessed using the Löe and Silness Gingival Index based on gingival color, edema, and bleeding tendency. Unit of Measure: Index score (0-3)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Periodontal health - Pocket Depth (PD)	Periodontal pocket depth measured as the distance from the gingival margin to the base of the periodontal pocket using a calibrated periodontal probe. Unit of Measure: Millimeters (mm)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Periodontal health - Presence of Gingival Recession	Presence of gingival recession defined as apical displacement of the gingival margin relative to the cemento-enamel junction. Unit of Measure: Presence of recession (yes/no)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Periodontal health - Clinical Crown Height	Clinical crown height measured on plaster dental models as the vertical distance from the gingival margin to the incisal edge or the tip of the cusp of the tooth. Unit of Measure: Millimeters (mm)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement
Dental alignment stability - Irregularity Index	Alignment of the mandibular anterior teeth is assessed using Little's Irregularity Index, defined as the sum of the linear displacements between the anatomic contact points of the six mandibular anterior teeth. The index quantifies anterior dental irregularity and is used to evaluate changes in tooth alignment and potential orthodontic relapse following retainer placement. Unit of Measure: Millimeters (mm)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Dental alignment stability - Intercanine Width	Transverse width of the dental arch measured as the linear distance between the cusp tips of the right and left mandibular canines on dental models. This measurement is used to assess transverse changes in the dental arch over time following orthodontic treatment and retainer placement. Unit of Measure: Millimeters (mm)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Dental alignment stability - Intermolar Width	Transverse width of the dental arch measured as the linear distance between the mesiobuccal cusp tips of the right and left mandibular first molars on dental models. This measurement is used to detect transverse changes in the posterior dental arch over time. Unit of Measure: Millimeters (mm)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.
Dental alignment stability - Arch Depth	Sagittal dimension of the dental arch measured on dental models as the perpendicular distance from the midpoint of the interincisal contact point to a line connecting the mesial surfaces of the right and left first molars. This measurement is used to evaluate changes in dental arch form over time. Unit of Measure: Millimeters (mm)	Baseline; 3, 6, 12, 18, and 24 months after retainer placement.

Collaborators and Investigators

• Sponsor: Piotr Fudalej
• Investigators: Principal Investigator: Piotr FUdalej, Jagiellonian University in Krakow

Publications and helpful links

General Publications

• 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.
• Pazera P, Fudalej P, Katsaros C. Severe complication of a bonded mandibular lingual retainer. Am J Orthod Dentofacial Orthop. 2012 Sep;142(3):406-9. doi: 10.1016/j.ajodo.2012.01.019.
• Pandis N, Fleming PS, Kloukos D, Polychronopoulou A, Katsaros C, Eliades T. Survival of bonded lingual retainers with chemical or photo polymerization over a 2-year period: a single-center, randomized controlled clinical trial. Am J Orthod Dentofacial Orthop. 2013 Aug;144(2):169-75. doi: 10.1016/j.ajodo.2013.02.030.
• Pandis N, Vlahopoulos K, Madianos P, Eliades T. Long-term periodontal status of patients with mandibular lingual fixed retention. Eur J Orthod. 2007 Oct;29(5):471-6. doi: 10.1093/ejo/cjm042.
• Booth FA, Edelman JM, Proffit WR. Twenty-year follow-up of patients with permanently bonded mandibular canine-to-canine retainers. Am J Orthod Dentofacial Orthop. 2008 Jan;133(1):70-6. doi: 10.1016/j.ajodo.2006.10.023.

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2014
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: March 8, 2026
• First Submitted That Met QC Criteria: March 12, 2026
• First Posted (Actual): March 17, 2026

Study Record Updates

• Last Update Posted (Actual): March 17, 2026
• Last Update Submitted That Met QC Criteria: March 12, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: satisfaction; survival; stability; periodontal status; orthodontic retention; bonded retainer; fixed retainer,
• Additional Relevant MeSH Terms: Behavior; Personal Satisfaction
• Other Study ID Numbers: KB/956/14

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No