Fixed Orthodontic RetainerOrtho-PerioNCT07718061
Bacterial Diversity Study Using 16S rRNA Sequencing of Periodontal Samples From Patients With Orthodontic Retainers
A study testing Fixed Orthodontic Retainer and Removable Essix-Type Orthodontic Retainer in people with Fixed Orthodontic Retainer and Orthodontic Appliances, Removable, run by Universidad de Murcia at 1 site in Spain.
Trial summary
After completion of orthodontic treatment, a retention phase is required to prevent relapse of tooth malposition. Fixed retention in the mandibular anterior region is commonly used. Read more about this study
- Who is it for?
- Ages 18 to 40 years
- Conditions the study is for
- Fixed Orthodontic Retainer, Orthodontic Appliances, Removable, Orthodontic Appliance Complication
- What is being tested?
- Fixed Orthodontic Retainer and Removable Essix-Type Orthodontic Retainer
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 10 participants
- Where
- 1 siteSpain
- Study dates
- 12 Jan 2026to Jul 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Treatment involving both dental arches
- Permanent dentition with at least 24 teeth
- Treatment duration longer than 12 months
- Treatment using the Versatile MBT system with a 0.022-inch slot
Who cannot join
- Patients with systemic disease or taking medications that may affect periodontal health
- Inadequate restorations or active carious lesions
- iodontal disease
- Plaque index greater than 20% before placement of the retainer or during the study
- Use of oral antiseptics within the previous 6 months or during the study period
- Use of antibiotics within the previous 14 days or during the study period
Show all 9Show fewer
- Smokers
- Pregnant or breastfeeding women
- Presence of open gingival embrasures, crowding, or dental malposition in the mandibular anterior region after orthodontic treatment
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Spain1 site, 1 recruiting
- Recruiting
University Dental Clinic
Murcia, 30008
Ascensión Vicente, DDS PhD, +34868888664, ascenvi@um.es
About this study
After completion of orthodontic treatment, a retention phase is required to prevent relapse of tooth malposition. Fixed retention in the mandibular anterior region is commonly used. This type of retainer is bonded to the lingual surfaces of the canines and incisors and may hinder oral hygiene, thereby promoting bacterial plaque accumulation and gingival inflammation.
Currently, probably due to the increasing use of clear aligner therapy, clear removable Essix-type retainers are becoming more widely used. Since these retainers can be removed by the patient, they may facilitate oral hygiene. However, studies assessing gingival health and the composition of the subgingival microbiota in patients wearing orthodontic retainers remain scarce.
Read more
Therefore, the aim of this study will be to assess the composition of the gingival sulcus microbiota and gingival health in patients wearing fixed or removable orthodontic retainers.
Ten adult patients who have completed orthodontic treatment will be recruited and divided into two groups:
- Fixed retention group.
- Removable retention group.
Periodontal parameters will be assessed, and bacterial plaque samples will be collected from the gingival sulcus at five time points:
T0: Bracket removal and dental scaling appointment. Periodontal parameters will be assessed, and plaque samples will be collected before bracket debonding and dental scaling.
T1: Retainer placement appointment, three days after T0. Periodontal parameters will be assessed, and plaque samples will be collected before retainer placement.
T2: One month after retainer placement.
T3: Three months after retainer placement.
T4: Six months after retainer placement.
Read the detailed description
The objectives of this study are:
- To compare the gingival sulcus microbiota in patients wearing fixed versus removable orthodontic retainers.
- To compare periodontal health in patients wearing fixed versus removable orthodontic retainers.
This prospective interventional comparative study will evaluate changes in gingival health and in the subgingival microbiota of adult patients following completion of orthodontic treatment with fixed multibracket appliances.
Ten participants attending the University Dental Clinic will be assigned to one of two retention groups: a fixed mandibular retainer group or a removable Essix-type retainer group.
Participants in the fixed retention group will receive a lingual retainer bonded from the mandibular left canine to the mandibular right canine, corresponding to teeth 33 to 43 according to the FDI tooth-numbering system. The same type of wire and bonding material will be used for all participants in this group.
Participants in the removable retention group will receive a clear Essix-type retainer manufactured using the same material and by the same dental technician. Participants will be instructed to wear the retainer for 22 hours per day.
To standardize oral hygiene procedures, all participants will receive the same oral hygiene instructions and an oral hygiene kit for use throughout the study period.
Clinical periodontal assessments and subgingival plaque sampling will be performed at five study visits:
T0: On the day of bracket removal and dental scaling. Periodontal assessments and plaque sampling will be performed before bracket debonding and scaling.
T1: Three days after T0, immediately before retainer placement.
T2: One month after retainer placement.
T3: Three months after retainer placement.
T4: Six months after retainer placement.
At each visit, periodontal health will be evaluated using plaque accumulation, bleeding on probing, probing pocket depth, clinical attachment level, and gingival recession.
Subgingival plaque samples will be collected from the mandibular anterior region using sterile paper points. Sampling will be performed at the mesial surface of each mandibular canine and at the mesial and distal surfaces of each mandibular incisor. The gingival tissue will be gently displaced to allow insertion of the paper point into the gingival sulcus without bending or contaminating the sample.
After collection, the portion of the paper point inserted into the gingival sulcus will be placed in an Eppendorf tube containing sterile phosphate-buffered saline. Samples will be stored at -22 °C until microbiological analysis.
The bacterial composition of the samples will be assessed using 16S ribosomal RNA gene sequencing. Changes in microbiota composition and periodontal parameters over time will be compared between the fixed and removable retention groups.
Participants will be instructed not to eat, drink, brush their teeth, or use mouthwash for at least two hours before each plaque-sampling visit.
- Conditions
- Fixed Orthodontic Retainer, Orthodontic Appliances, Removable, Orthodontic Appliance Complication, Gingivitis, Periodontal Diseases
- Being tested
- Fixed Orthodontic Retainer, Removable Essix-Type Orthodontic Retainer
- Keywords
- Orthodontic retainer, Periodontal health, Gingivitis, Microbiota
- Medical subject headings
- Gingivitis, Periodontal Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fixed Orthodontic RetainerDevice
A fixed lingual orthodontic retainer bonded to the mandibular anterior teeth, extending from tooth 33 to tooth 43
Removable Essix-Type Orthodontic RetainerDevice
A clear removable Essix-type orthodontic retainer prescribed for 22 hours of daily wear
| Study group | Role | What they receive |
|---|---|---|
| Fixed Orthodontic Retention | Active comparator | Participants assigned to this arm will receive a fixed lingual orthodontic retainer bonded to the mandibular anterior teeth, extending from tooth 33 to tooth 43. The same retainer wire and bonding materials will be used for all participants Receives: Device: Fixed Orthodontic Retainer |
| Removable Essix-Type Orthodontic Retention | Experimental | Participants assigned to this arm will receive a clear removable Essix-type orthodontic retainer. Participants will be instructed to wear the retainer for 22 hours per day. All retainers will be manufactured using the same material and by the same dental technician. Receives: Device: Removable Essix-Type Orthodontic Retainer |
What is being measured
The primary outcome is the main question the study is designed to answer.
Longitudinal change in subgingival microbial community composition assessed using Bray-Curtis dissimilarity
Subgingival plaque samples collected from the mandibular anterior teeth will be analyzed using 16S rRNA gene sequencing. Overall microbial community composition will be assessed using the Bray-Curtis dissimilarity index. Longitudinal differences in microbial community composition will be evaluated between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers, considering the effect of study group, assessment time point, and their interaction.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in bleeding on probing
Bleeding on probing will be recorded as present or absent at six sites per tooth in the mandibular anterior region following gentle periodontal probing. The outcome will be calculated as the percentage of examined sites showing bleeding for each participant. Longitudinal changes in bleeding on probing will be compared between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers, considering the effect of study group, assessment time point, and their interaction.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Secondary outcomes (9)
Longitudinal change in subgingival microbial alpha diversity assessed using the Shannon diversity index
Subgingival plaque samples collected from the mandibular anterior teeth will be analyzed using 16S rRNA gene sequencing. Alpha diversity will be quantified using the Shannon diversity index for each sample. Higher values indicate greater microbial diversity within the sample. Longitudinal changes will be compared between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers, considering study group, assessment time point, and their interaction.
Time Frame
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in subgingival microbial evenness assessed using Pielou's evenness index
Microbial community evenness will be quantified using Pielou's evenness index calculated from the 16S rRNA gene sequencing data. The index ranges from 0 to 1, with higher values indicating a more even distribution of bacterial taxa within the microbial community. Longitudinal changes will be compared between the fixed-retainer and removable-retainer groups across all study visits.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in subgingival microbial dominance assessed using the Simpson dominance index
Microbial dominance will be quantified using the Simpson dominance index calculated from the 16S rRNA gene sequencing data. Higher index values indicate greater dominance of the microbial community by a limited number of bacterial taxa. Longitudinal changes will be compared between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers across all study visits.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in subgingival microbial taxonomic composition
The relative abundance of bacterial taxa identified by 16S rRNA gene sequencing will be calculated as the percentage of sequencing reads assigned to each taxon. Taxonomic composition will be evaluated at the phylum, family, and genus levels and, where technically feasible, at the species level. Longitudinal changes will be compared between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Differential abundance of subgingival bacterial taxa
Differential abundance analysis will be performed using 16S rRNA gene sequencing data to identify bacterial taxa whose abundance differs between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers, as well as taxa showing changes over time within each group. Correction for multiple comparisons will be applied.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in plaque index
The presence or absence of dental plaque will be recorded at six surfaces per tooth in the mandibular anterior region: three buccal surfaces and three lingual surfaces. The plaque index will be calculated for each participant as the percentage of examined surfaces showing detectable plaque. Longitudinal changes will be compared between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in periodontal probing depth
Periodontal probing depth will be measured in millimeters from the gingival margin to the base of the gingival sulcus or periodontal pocket using a periodontal probe. Measurements will be recorded at six sites per tooth in the mandibular anterior region. The mean probing depth will be calculated for each participant, and longitudinal changes will be compared between study groups.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in clinical attachment level
Clinical attachment level will be measured in millimeters from the cementoenamel junction to the base of the gingival sulcus or periodontal pocket. Measurements will be recorded at six sites per tooth in the mandibular anterior region. The mean clinical attachment level will be calculated for each participant, and longitudinal changes will be compared between study groups.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in gingival recession
Gingival recession will be measured in millimeters from the cementoenamel junction to the gingival margin when the gingival margin is located apical to the cementoenamel junction. Measurements will be recorded at six sites per tooth in the mandibular anterior region. The mean gingival recession will be calculated for each participant, and longitudinal changes will be compared between study groups.
Measured: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2026
- Study start12 Jan 2026
- Primary completionJul 2027 (estimated)
- Study completionJul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (9)Papers the sponsor has linked to this study.
- Other trials for Fixed Orthodontic RetainerStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- This is a prospective, two-arm, parallel-group interventional study. Ten adult participants completing orthodontic treatment with fixed multibracket appliances will be allocated to receive either a fixed mandibular lingual retainer or a removable Essix-type retainer. Periodontal parameters and subgingival plaque samples will be assessed before retainer placement and at 1, 3, and 6 months after retainer placement.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 10 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universidad de Murcia
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Antonio J Ortiz Ruiz, MD PhD, Study chair, Universidad de Murcia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07718061
- Sponsor's protocol ID
- 725/2025
- Acronym
- Ortho-Perio
- Status last verified
- Jul 2026
- First submitted
- 16 Jul 2026
- Last updated
- 28 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Yanez-Vico RM, Iglesias-Linares A, Ballesta-Mudarra S, Ortiz-Ariza E, Solano-Reina E, Perea EJ. Short-term effect of removal of fixed orthodontic appliances on gingival health and subgingival microbiota: a prospective cohort study. Acta Odontol Scand. 2015;73(7):496-502. doi: 10.3109/00016357.2014.993701. Epub 2015 Jan 29.
PubMed 25631494Choi DS, Cha BK, Jost-Brinkmann PG, Lee SY, Chang BS, Jang I, Song JS. Microbiologic changes in subgingival plaque after removal of fixed orthodontic appliances. Angle Orthod. 2009 Nov;79(6):1149-55. doi: 10.2319/111808-593R.1.
PubMed 19852608Pan S, Liu Y, Zhang L, Li S, Zhang Y, Liu J, Wang C, Xiao S. Profiling of subgingival plaque biofilm microbiota in adolescents after completion of orthodontic therapy. PLoS One. 2017 Feb 3;12(2):e0171550. doi: 10.1371/journal.pone.0171550. eCollection 2017.
PubMed 28158292Levin L, Samorodnitzky-Naveh GR, Machtei EE. The association of orthodontic treatment and fixed retainers with gingival health. J Periodontol. 2008 Nov;79(11):2087-92. doi: 10.1902/jop.2008.080128.
PubMed 18980517Manzon L, Fratto G, Rossi E, Buccheri A. Periodontal health and compliance: A comparison between Essix and Hawley retainers. Am J Orthod Dentofacial Orthop. 2018 Jun;153(6):852-860. doi: 10.1016/j.ajodo.2017.10.025.
PubMed 29853243Al-Moghrabi D, Johal A, O'Rourke N, Donos N, Pandis N, Gonzales-Marin C, Fleming PS. Effects of fixed vs removable orthodontic retainers on stability and periodontal health: 4-year follow-up of a randomized controlled trial. Am J Orthod Dentofacial Orthop. 2018 Aug;154(2):167-174.e1. doi: 10.1016/j.ajodo.2018.01.007.
PubMed 30075919Rody WJ Jr, Elmaraghy S, McNeight AM, Chamberlain CA, Antal D, Dolce C, Wheeler TT, McGorray SP, Shaddox LM. Effects of different orthodontic retention protocols on the periodontal health of mandibular incisors. Orthod Craniofac Res. 2016 Nov;19(4):198-208. doi: 10.1111/ocr.12129. Epub 2016 Sep 20.
PubMed 27647720Eroglu AK, Baka ZM, Arslan U. Comparative evaluation of salivary microbial levels and periodontal status of patients wearing fixed and removable orthodontic retainers. Am J Orthod Dentofacial Orthop. 2019 Aug;156(2):186-192. doi: 10.1016/j.ajodo.2018.08.022.
PubMed 31375228Li B, Lu C, Yao X, Wu X, Wu G, Zeng X. Effects of three orthodontic retainers on periodontal pathogens and periodontal parameters. Sci Rep. 2023 Nov 24;13(1):20709. doi: 10.1038/s41598-023-46922-2.
PubMed 38001102
Study at a glance
From the registry record, last updated by the sponsor on 28 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bacterial Diversity Study Using 16S rRNA Sequencing of Periodontal Samples From Patients With Orthodontic Retainers
- ClinicalTrials.gov ID
- NCT07718061
- Acronym / sponsor ID
- Ortho-Perio / 725/2025
- Conditions
- Fixed Orthodontic Retainer, Orthodontic Appliances, Removable, Orthodontic Appliance Complication, Gingivitis, Periodontal Diseases
- Keywords
- Orthodontic retainer, Periodontal health, Gingivitis, Microbiota
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 10 participants (estimated)
- Lead sponsor
- Universidad de MurciaUniversity, hospital or other
- Study start
- 12 Jan 2026 (actual)
- Primary completion
- Jul 2027 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 21 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
After completion of orthodontic treatment, a retention phase is required to prevent relapse of tooth malposition. Fixed retention in the mandibular anterior region is commonly used. This type of retainer is bonded to the lingual surfaces of the canines and incisors and may hinder oral hygiene, thereby promoting bacterial plaque accumulation and gingival inflammation.
Currently, probably due to the increasing use of clear aligner therapy, clear removable Essix-type retainers are becoming more widely used. Since these retainers can be removed by the patient, they may facilitate oral hygiene. However, studies assessing gingival health and the composition of the subgingival microbiota in patients wearing orthodontic retainers remain scarce.
Therefore, the aim of this study will be to assess the composition of the gingival sulcus microbiota and gingival health in patients wearing fixed or removable orthodontic retainers.
Ten adult patients who have completed orthodontic treatment will be recruited and divided into two groups:
- Fixed retention group.
- Removable retention group.
Periodontal parameters will be assessed, and bacterial plaque samples will be collected from the gingival sulcus at five time points:
T0: Bracket removal and dental scaling appointment. Periodontal parameters will be assessed, and plaque samples will be collected before bracket debonding and dental scaling.
T1: Retainer placement appointment, three days after T0. Periodontal parameters will be assessed, and plaque samples will be collected before retainer placement.
T2: One month after retainer placement.
T3: Three months after retainer placement.
T4: Six months after retainer placement.
Detailed description
The objectives of this study are:
- To compare the gingival sulcus microbiota in patients wearing fixed versus removable orthodontic retainers.
- To compare periodontal health in patients wearing fixed versus removable orthodontic retainers.
This prospective interventional comparative study will evaluate changes in gingival health and in the subgingival microbiota of adult patients following completion of orthodontic treatment with fixed multibracket appliances.
Ten participants attending the University Dental Clinic will be assigned to one of two retention groups: a fixed mandibular retainer group or a removable Essix-type retainer group.
Participants in the fixed retention group will receive a lingual retainer bonded from the mandibular left canine to the mandibular right canine, corresponding to teeth 33 to 43 according to the FDI tooth-numbering system. The same type of wire and bonding material will be used for all participants in this group.
Participants in the removable retention group will receive a clear Essix-type retainer manufactured using the same material and by the same dental technician. Participants will be instructed to wear the retainer for 22 hours per day.
To standardize oral hygiene procedures, all participants will receive the same oral hygiene instructions and an oral hygiene kit for use throughout the study period.
Clinical periodontal assessments and subgingival plaque sampling will be performed at five study visits:
T0: On the day of bracket removal and dental scaling. Periodontal assessments and plaque sampling will be performed before bracket debonding and scaling.
T1: Three days after T0, immediately before retainer placement.
T2: One month after retainer placement.
T3: Three months after retainer placement.
T4: Six months after retainer placement.
At each visit, periodontal health will be evaluated using plaque accumulation, bleeding on probing, probing pocket depth, clinical attachment level, and gingival recession.
Subgingival plaque samples will be collected from the mandibular anterior region using sterile paper points. Sampling will be performed at the mesial surface of each mandibular canine and at the mesial and distal surfaces of each mandibular incisor. The gingival tissue will be gently displaced to allow insertion of the paper point into the gingival sulcus without bending or contaminating the sample.
After collection, the portion of the paper point inserted into the gingival sulcus will be placed in an Eppendorf tube containing sterile phosphate-buffered saline. Samples will be stored at -22 °C until microbiological analysis.
The bacterial composition of the samples will be assessed using 16S ribosomal RNA gene sequencing. Changes in microbiota composition and periodontal parameters over time will be compared between the fixed and removable retention groups.
Participants will be instructed not to eat, drink, brush their teeth, or use mouthwash for at least two hours before each plaque-sampling visit.
Study design
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- This is a prospective, two-arm, parallel-group interventional study. Ten adult participants completing orthodontic treatment with fixed multibracket appliances will be allocated to receive either a fixed mandibular lingual retainer or a removable Essix-type retainer. Periodontal parameters and subgingival plaque samples will be assessed before retainer placement and at 1, 3, and 6 months after retainer placement.
| Arm | Type | Receives |
|---|---|---|
| Fixed Orthodontic Retention | Active comparator | Device: Fixed Orthodontic RetainerParticipants assigned to this arm will receive a fixed lingual orthodontic retainer bonded to the mandibular anterior teeth, extending from tooth 33 to tooth 43. The same retainer wire and bonding materials will be used for all participants |
| Removable Essix-Type Orthodontic Retention | Experimental | Device: Removable Essix-Type Orthodontic RetainerParticipants assigned to this arm will receive a clear removable Essix-type orthodontic retainer. Participants will be instructed to wear the retainer for 22 hours per day. All retainers will be manufactured using the same material and by the same dental technician. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Treatment involving both dental arches
- Permanent dentition with at least 24 teeth
- Treatment duration longer than 12 months
- Treatment using the Versatile MBT system with a 0.022-inch slot
Key exclusion criteria (9 listed)
- Patients with systemic disease or taking medications that may affect periodontal health
- Inadequate restorations or active carious lesions
- iodontal disease
- Plaque index greater than 20% before placement of the retainer or during the study
- Use of oral antiseptics within the previous 6 months or during the study period
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fixed Orthodontic RetainerA fixed lingual orthodontic retainer bonded to the mandibular anterior teeth, extending from tooth 33 to tooth 43 | Device | Fixed Orthodontic Retention |
| Removable Essix-Type Orthodontic RetainerA clear removable Essix-type orthodontic retainer prescribed for 22 hours of daily wear | Device | Removable Essix-Type Orthodontic Retention |
Primary outcome
Longitudinal change in subgingival microbial community composition assessed using Bray-Curtis dissimilarity
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Subgingival plaque samples collected from the mandibular anterior teeth will be analyzed using 16S rRNA gene sequencing. Overall microbial community composition will be assessed using the Bray-Curtis dissimilarity index. Longitudinal differences in microbial community composition will be evaluated between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers, considering the effect of study group, assessment time point, and their interaction.
Longitudinal change in bleeding on probing
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Bleeding on probing will be recorded as present or absent at six sites per tooth in the mandibular anterior region following gentle periodontal probing. The outcome will be calculated as the percentage of examined sites showing bleeding for each participant. Longitudinal changes in bleeding on probing will be compared between participants receiving fixed orthodontic retainers and those receiving removable Essix retainers, considering the effect of study group, assessment time point, and their interaction.
9 secondary outcomes
Longitudinal change in subgingival microbial alpha diversity assessed using the Shannon diversity index
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in subgingival microbial evenness assessed using Pielou's evenness index
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in subgingival microbial dominance assessed using the Simpson dominance index
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in subgingival microbial taxonomic composition
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Differential abundance of subgingival bacterial taxa
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in plaque index
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in periodontal probing depth
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in clinical attachment level
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Longitudinal change in gingival recession
Time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Jul 2026.
- Background: PubMed 25631494Yanez-Vico RM, Iglesias-Linares A, Ballesta-Mudarra S, Ortiz-Ariza E, Solano-Reina E, Perea EJ. Short-term effect of removal of fixed orthodontic appliances on gingival health and subgingival microbiota: a prospective cohort study. Acta Odontol Scand. 2015;73(7):496-502. doi: 10.3109/00016357.2014.993701. Epub 2015 Jan 29.
- Background: PubMed 19852608Choi DS, Cha BK, Jost-Brinkmann PG, Lee SY, Chang BS, Jang I, Song JS. Microbiologic changes in subgingival plaque after removal of fixed orthodontic appliances. Angle Orthod. 2009 Nov;79(6):1149-55. doi: 10.2319/111808-593R.1.
- Background: PubMed 28158292Pan S, Liu Y, Zhang L, Li S, Zhang Y, Liu J, Wang C, Xiao S. Profiling of subgingival plaque biofilm microbiota in adolescents after completion of orthodontic therapy. PLoS One. 2017 Feb 3;12(2):e0171550. doi: 10.1371/journal.pone.0171550. eCollection 2017.
- Background: PubMed 18980517Levin L, Samorodnitzky-Naveh GR, Machtei EE. The association of orthodontic treatment and fixed retainers with gingival health. J Periodontol. 2008 Nov;79(11):2087-92. doi: 10.1902/jop.2008.080128.
- Background: PubMed 29853243Manzon L, Fratto G, Rossi E, Buccheri A. Periodontal health and compliance: A comparison between Essix and Hawley retainers. Am J Orthod Dentofacial Orthop. 2018 Jun;153(6):852-860. doi: 10.1016/j.ajodo.2017.10.025.
- Background: PubMed 30075919Al-Moghrabi D, Johal A, O'Rourke N, Donos N, Pandis N, Gonzales-Marin C, Fleming PS. Effects of fixed vs removable orthodontic retainers on stability and periodontal health: 4-year follow-up of a randomized controlled trial. Am J Orthod Dentofacial Orthop. 2018 Aug;154(2):167-174.e1. doi: 10.1016/j.ajodo.2018.01.007.
- Background: PubMed 27647720Rody WJ Jr, Elmaraghy S, McNeight AM, Chamberlain CA, Antal D, Dolce C, Wheeler TT, McGorray SP, Shaddox LM. Effects of different orthodontic retention protocols on the periodontal health of mandibular incisors. Orthod Craniofac Res. 2016 Nov;19(4):198-208. doi: 10.1111/ocr.12129. Epub 2016 Sep 20.
- Background: PubMed 31375228Eroglu AK, Baka ZM, Arslan U. Comparative evaluation of salivary microbial levels and periodontal status of patients wearing fixed and removable orthodontic retainers. Am J Orthod Dentofacial Orthop. 2019 Aug;156(2):186-192. doi: 10.1016/j.ajodo.2018.08.022.
- Background: PubMed 38001102Li B, Lu C, Yao X, Wu X, Wu G, Zeng X. Effects of three orthodontic retainers on periodontal pathogens and periodontal parameters. Sci Rep. 2023 Nov 24;13(1):20709. doi: 10.1038/s41598-023-46922-2.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Antonio J Ortiz Ruiz, MD PhD study chair
Universidad de Murcia
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fixed Orthodontic Retainer and Removable Essix-Type Orthodontic Retainer in people with Fixed Orthodontic Retainer and Orthodontic Appliances, Removable, run by Universidad de Murcia at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 28 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Ascensión Vicente, DDS PhD (+3486888664, ascenvi@um.es), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Longitudinal change in subgingival microbial community composition assessed using Bray-Curtis dissimilarity (time frame: T0: pre-debonding; T1: pre-retainer baseline, 3 days after T0; T2: 1 month post-retainer; T3: 3 months post-retainer; T4: 6 months post-retainer.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07718061, which also lists 9 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Jul 2026; AzTrials last refreshed its copy on 6 Nov 2026.