The Role of Fluoride Varnish Application in Preventing White Spot Lesions During Clear Aligner Treatment: A Controlled Split-Mouth Study

aim of study: is to compare the effect of the fluoride varnish application on the prevention of white spot lesions (WSLs) during clear aligner therapy

Design Details: Each participant will have one side of the mouth assigned to the fluoride varnish intervention, while the contralateral side will serve as the control without fluoride varnish.

Outcomes:

Primary outcome: Incidence and Severity of White Spot Lesions Measured before and after six months using Laser fluorescence (DIAGNOdent)

Secondary Outcome:

Periodontal Ligament (PDL) Health using pocket Depth Index (PDI) Gingival Bleeding and Inflammation using bleeding on Probing Index (BOP)

Study Overview

• Status: Active, not recruiting
• Conditions: White Spot Lesion
• Intervention / Treatment: Other: White spot lesion with fluoride varnish application; Other: White spot lesion without fluoride varnish application

Detailed Description

aim of study: is to compare the effect of the fluoride varnish application on the prevention of white spot lesions (WSLs) during clear aligner therapy in comparison to a split mouth-controlled group

Sample size calculation:

The sample size was calculated using G* power software (version3.1.9.7) and was designed to have a power of 85% assuming a type I statistical error of 5% and a one tailed statistical test with an effect size f= 0.7730012 based on the study of Najafi et al. The means and standard deviation of the DIAGNOdent score of the varnish and control groups after six months were 1.23 ±0.45 and 1.78±0.90. The calculated sample size will be 25 patients. The sample size will be increased to include 30 patients to avoid any drop out.

Material and methods:

1. Initial Oral Scan:

   • A 3D oral scan of the arch to be treated will be performed using a digital intraoral scanner

2. Aligner Fabrication:

   • aligners will be fabricated using thermoforming techniques.
   • A clear aligner sheet (e.g.Duran) is heated and vacuum or pressure-formed over the 3D-printed model, then trimming followed by finishing and polishing
3. Interventions

Intervention Group (Test Side):

• Application of a preventive fluoride varnish (Charm varnish) on the indicated side of the mouth before clear aligner fitting.

Control Group (Control Side):

• Without application of fluoride varnish 4. Aligner Placement:
• The aligners will be fitted, and patients will wear them continuously, except during eating and brushing.

Outcome Measures:

Primary Outcome:

• Incidence and Severity of White Spot Lesions Measured before and after six months using Laser fluorescence (DIAGNOdent)

Secondary Outcome:

1. Periodontal Ligament (PDL) Health using:

   • Pocket Depth Index (PDI)

2. Gingival Bleeding and Inflammation using:

   • Bleeding on Probing Index (BOP)

Randomization and Application Site

To minimize bias, the side of the maxillary arch (right or left upper side) for fluoride varnish application was randomly assigned for each of the patients using a computer-generated randomization sequence

Inclusion and Exclusion Criteria Eligible participants were patients aged 16-24 years, representing the typical demographic for clear aligner therapy and ensuring biological consistency in terms of tooth development and orthodontic response. All participants were required to be in good general and oral health to minimize confounding factors related to systemic or oral disease, to present with mild dental crowding in each arch to standardize treatment complexity, and to have full eruption of all permanent teeth excluding third molars to allow consistent varnish application and assessment. Patients were excluded if they had a known allergy or hypersensitivity to fluoride-containing materials, systemic conditions that could affect tooth movement (such as diabetes or bone metabolism disorders), cleft lip and/or palate or other craniofacial anomalies, a history of previous orthodontic treatment, or clinical evidence of dental fluorosis, as these factors could alter enamel characteristics, orthodontic response, or lesion assessment and thereby introduce bias into the study outcomes.

Duration of the study:

• This study is suggested to be finished in 18 months

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Al Mansurah, Egypt
    • Faculty of Dentistry Mansoura University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• patients aged 16-24 years.
• Good general and oral health.
• Mild dental crowding per arch (≤ 4 mm).
• Eruption of all permanent dention excluding third molar

Exclusion Criteria:

• Allergy to fluoride material
• Systemic conditions affecting tooth movement (e.g., diabetes, bone disorders).
• Patients with Cleft lip and palate
• Previous orthodontic treatment
• dental fluorosis.
• hypocalcified teeth or visible demineralization

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: White spot lesion with fluoride varnish application during clear Aligner therapy; Intervention Group (Test Side): • Application of a preventive fluoride varnish on the indicated side of the mouth before clear aligner fitting.	Other: White spot lesion with fluoride varnish application; Application of fluoride varnish at the cervical third of labial surface or around the attachment if present
Active Comparator: White spot lesion without fluoride varnish application during clear Aligner therapy; Control Group (Control Side): No application of fluoride varnish.	Other: White spot lesion without fluoride varnish application; No fluoride varnish application at the cervical third of the labial surface or around the attachment if present

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence and Severity of White Spot Lesions	Incidence and Severity of White Spot Lesions Measured before and after six months using Laser fluorescence (DIAGNOdent)	Six months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Periodontal Ligament (PDL) Health	Health using pocket Depth Index (PDI)	Six moths
Gingival Bleeding and Inflammation	using bleeding on Probing Index (BOP)	Six months

Collaborators and Investigators

• Sponsor: Mansoura University

Study record dates

Study Major Dates

• Study Start (Actual): June 25, 2025
• Primary Completion (Estimated): January 25, 2027
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: December 20, 2025
• First Submitted That Met QC Criteria: December 20, 2025
• First Posted (Actual): January 6, 2026

Study Record Updates

• Last Update Posted (Actual): January 6, 2026
• Last Update Submitted That Met QC Criteria: December 20, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: Mansoura-university

Drug and device information, study documents

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