Comparison Between Periodontal Effects of Fixed and Vacuum-Formed Retainers

Clinical Evaluation of Gingival and Periodontal Health of Lower Anterior Teeth With Fixed Retainer Versus Removable Retainer: A Randomized Clinical Trial.

One of the most crucial aspects of orthodontic therapy is retention, which is required to prevent orthodontic relapse . There are two main types of retainers, removable retainer which depends on patient compliance to achieve proper results, and fixed retainer which can overcome the problem of patient compliance, but with using it there is higher risk of plaque accumulation and the process of brushing teeth becomes more complex. However, it is not known whether this necessarily leads to worsening of periodontal outcomes . The increasing use of permanent retainers and their requirement for continuous wear highlight the importance of evaluating their impact on the periodontal health but there is conflicting data available right now on how orthodontic retainers affect periodontal diseases

Study Overview

• Status: Active, not recruiting
• Conditions: Periodontal Health; Orthodontic; Retainer
• Intervention / Treatment: Device: Fixed retainer; Device: vacuum retainer

Detailed Description

The purpose of this research is to compare the effect between fixed and removable retainer on periodontium as the current evidence on how these appliances affect periodontal health is still lacking significantly Orthodontic treatment plays an important role in enhancing the function, esthetics and overall well-being of patients. One of the most important elements of treatment is the retention phase. There are two main types of retainers that can be used in the retention phase either fixed or removable.

At first banded fixed appliances were used as retainers , then in 1919 Hawly introduced removable retainers , then in 1973 Kneirim RW. introduced the first bonded retainer as enamel etching and modern adhesive systems facilitated the use of bonded retention .

The most widely used removable retainer is the Hawley appliance, which is made of wire and acrylic resin.

In 1971 Ponitz introduced fiber reinforced retainer which is less expensive, with better esthetics and easy to clean but it is not dimensionally stable and more prone to wearing.

The duration of the retention phase frequently exceeds that of the active treatment. In many cases, orthodontists even propose lifetime retention.

Removable retainers depend greatly on patient compliance so fixed compliance-free retainers were introduced but they cause more plaque accumulation and make the process of brushing teeth more complex, also there is conflicting data about their effect on periodontal health Artun was one of the first orthodontists to investigate the periodontal effect of fixed retainers. He found out that more plaque accumulation occurred with fixed retainers, but he suggested that plaque and calculus accumulation gingival to the retainer wire might not cause serious damage to the periodontium According to the most recent Cochrane review concerning this matter, most of the studies found no difference in periodontal measurements between the two types of retainers but one study found that the lower fixed retainer group had considerably more periodontal pocketing and bleeding on probing than the full-time lower removable retainer . Nevertheless, it is important to exercise caution when interpreting this periodontal pocketing outcome because the two groups were not similar at debonding, with four times as many participants in the fixed retainer group

The most recent systematic reviews also concluded that the available evidence on this topic is inconclusive and that more research is needed which would help in choosing the suitable type of retainer for each patient as there are no specific guidelines for choosing one type of retainer over the other for each patient. But they concluded that fixed retainers are compatible with periodontal health, or at least not related to severe detrimental effects on the periodontium.

It must also be taken in consideration several factors when interpreting the results of effect of fixed retainers on periodontal health like Hawthrone effect, limited follow up period and selection bias as most studies select people with good periodontal health .

The concept of periodontal health was derived from Chapple et al. and is basically defined as having no clinical loss of attachment, limited bleeding on probing (< 10%), and no significantly elevated probing depths (≤ 3 mm)

• Study Type: Interventional
• Enrollment (Actual): 46
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt
    • Faculty of Dentistry Cairo university

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Minimal age of twelve years.
• Presence of all mandibular anterior teeth from canine to canine.
• Completion of orthodontic multi-bracket treatment with the requirement of retention of the mandibular anterior teeth.
• Periodontal screening index ≤ 2 [18].
• Participation in all study visits.

Exclusion Criteria:

• Systemic disease potentially affecting the study outcome.
• Conditions requiring antibiotic prophylaxis for clinical measurements that trigger transitory bacteremia.
• Pregnant females.
• Chronic use of medications affecting the study outcome.
• Patients with active periodontal disease

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: intervention group ( fixed retainer group); At first, medical and dental histories will be taken from the patients then extra- and intra-oral examinations will follow.; Brackets are removed using a plier at the end of active orthodontic treatment.; Excess adhesive material is removed using finishing stones and rubber polishing kit.; Polishing the teeth before placement of retainer. For the fixed retainer group, it will be fabricated from a stainless-steel alloy and applied to each lingual tooth surface from one mandibular canine to the contralateral canine. The patients' teeth surfaces will then be prepared using 37% phosphoric acid etchant gel for 30 seconds, rinsed and dried with oil-free compressed air for 10 seconds. After drying the enamel surfaces, a bonding agent will be applied using a micro-brush, spread using oil-free compressed air followed by the application of the adhesive material and placement of the fixed retainer. After light curing excess adhesive material will be removed.	Device: Fixed retainer; Patients are given oral hygiene instructions during retention period , frequent follow up visits with patients
Active Comparator: control group ( vacuum retainer group); At first, medical and dental histories will be taken from the patients then extra- and intra-oral examinations will follow.; Brackets are removed using a plier at the end of active orthodontic treatment.; Excess adhesive material is removed using finishing stones and rubber polishing kit.; Polishing the teeth before placement of retainer. For the removable retainer group the mandibular removable retainers will be fabricated using thick thermoplastic vacuum-formed sheets, patients will be instructed to wear them full- time.	Device: vacuum retainer; Patients are given oral hygiene instructions during retention period , frequent follow up visits with the patients

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Probing depth	Assessment of periodontal health using Periodontal probing depth Probing depth is measured in mms using periodontal probe, in a healthy periodontium pocket typically measures between 1 to 3 millimeters in depth	immediately after debonding and after 6 months
Bleeding on probing	Bleeding on probing is a 4 point scale Score 0: No bleeding No bleeding when you probe the gingival sulcus/pocket Score 1: Bleeding on probing Bleeding occurs after probing, usually within 10-30 seconds ,Mild bleeding at the gingival margin Score 2: Bleeding + profuse Bleeding is immediate, profuse, and often fills the sulcus, Or bleeding flows from the sulcus Score 3: Spontaneous bleeding, Bleeding occurs without any probing Seen before you even touch the tissue	immediately after debonding and after 6 months
gingival recession	Loss of clinical attachment level is measured as the distance in millimeters between the bottom of the pocket and the cementoenamel junction. Based on the extent of attachment loss, it can be categorized as light (1-2 mm), moderate (3-4 mm), or severe (5 mm or more) loss of clinical attachment.	immediately after debonding and after 6 months
Gingival index	Gingival index is a 4-point scale in which scale 0 is healthy periodontium and scale 3 is severe inflammation.	immediately after debonding and after 6 months
plaque index	Plaque index is a 4-point scale in which scale 0 indicates the absence of plaque at the free gingival margin after drying, and scale 3 represents an abundance of soft matter within the gingival pocket and/or on the gingival margin and adjacent tooth surface, including the interdental area	immediately after debonding and after 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
patient satisfaction	Assessment of patient satisfaction using questionnaire.	After 6 months

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Actual): November 21, 2025
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: June 9, 2026
• First Submitted That Met QC Criteria: June 12, 2026
• First Posted (Actual): June 16, 2026

Study Record Updates

• Last Update Posted (Actual): June 16, 2026
• Last Update Submitted That Met QC Criteria: June 12, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Dentistry; Orthodontic Appliances; Orthodontics; Orthodontic Appliances, Fixed
• Other Study ID Numbers: ??1125

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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