Evaluation of Green Tea Extract and Casein Phosphopeptide- Amorphous Calcium Phosphate (CPP-ACP) effect on white spot recovery in retention phase of fixed orthodontic treatment: A Triple-Blind Randomized Clinical Trial

This study evaluates whether the orthodontic retention phase can be used not only for tooth stabilization but also for treating white spot lesions, comparing green tea extract with CPP‑ACP as a more accessible natural option.

A randomized, triple‑blind, parallel‑group, controlled Phase 3 clinical trial conducted on 36 teeth in each intervention group (the study includes two intervention groups). Randomization will be performed using a random numbers table.

This study will be performed in clinics affiliated with Isfahan University of Medical Sciences, including the TorabiNejad, Ghaedi, and Afzal clinics. Each patient receives two syringes: one contains CPP‑ACP or green tea and one placebo, applied nightly to the reservoir spaces. Lesions are measured with a DIAGNOdent Pen at baseline, 1 month, and 2 months. The study is triple‑blinded (patient, operator, and statistician). Randomizing the distribution of the sample is done using a random number table.

Inclusion criteria: Age 15 to 30 years; Presence of at least one white spot lesion with a DIAGNOdent score between 10 and 20 on the corresponding teeth on both sides of one arch. Exclusion criteria: Systemic diseases, Tooth rotation, gingival hyperplasia, and tobacco use.

Intervention group Includes two subgroups of 36 teeth each with white spot lesions (DIAGNOdent 10–20). These teeth are treated with either green tea extract or CPP‑ACP paste. Comparison group Includes two corresponding subgroups of 36 contralateral teeth with the same DIAGNOdent range (10–20). These teeth receive a placebo.

WSLs remineralization

The study for each ingredient will be conducted in a split‑mouth design. Considering the differences in individuals’ brushing patterns on the dominant and non‑dominant side (depending on right‑ or left‑handedness), and the potential differences in oral hygiene accuracy and fluoride exposure between the two sides of the jaw, the number of teeth receiving the intervention on the dominant side will also be kept equal. Therefore, Group 1 will include 36 teeth (18 pairs), in which 18 teeth on the dominant side (according to right‑ or left‑handedness) will receive green tea extract and the contralateral teeth will receive placebo. Another 18 teeth on the non‑dominant side will receive green tea extract and the opposite teeth will receive placebo. Group 2 will include 36 teeth (18 pairs), in which 18 teeth on the dominant side will receive CPP‑ACP paste and the contralateral teeth will receive placebo. Another 18 teeth on the non‑dominant side will receive CPP‑ACP paste and the opposite teeth will receive placebo. Randomization of sample allocation will be performed using simple randomization based on a random number table.

The patient is given two syringes, one containing the intervention material (CPP-ACP or green tea) and the other containing a placebo. The patient is unaware of which syringe contains the active material or the placebo. During the evaluation; after one and two months, the assessment is performed by a second investigator who is blinded to the side of the intervention. During data analysis as well, the statistical analyst will have no information regarding the type of intervention used in the patients’ mouths or the side on which it was applied. Therefore, the study will be triple-blind, and the patient, the intervention provider, and the statistical analyst will all be unaware of the type of material used for application, delivery to the patients, or the assessment and analysis of remineralization.

In addition to the main information containing the primary outcome, other necessary information, such as demographic data, the level of participant cooperation and... can also be published if necessary, provided that no personally identifiable information is disclosed.

The access period begins 3 months after the publication of the results.

Provided that all participants’ rights in the study are fully respected and their contact or identifying information is not disclosed, it is possible to share their non-private data with all academic or non-academic researchers, as well as pharmaceutical development companies.

The data are shared solely to make the study more transparent and to allow their use for research purposes as well as for development and production activities in pharmaceutical companies and similar organizations.

For this purpose, requests should be sent to the email address of the corresponding author. The corresponding author’s email address is: parnianrdi2@gmail.com

The applicant must clearly state the reasons for requesting additional information and acknowledge that only non‑private participant data can be provided. After submitting the request, the applicant should allow up to two weeks for the required information to be delivered.