Comparison of mandibular canine to canine fixed retainer failure rate bonded by two types of adhesives (GC flowable composite and GC Gradia composite) in orthodontic patients and investigating its relationship with de-bonding rate of brackets: RCT

Comparing the failure rate of the fixed retainer in two types of composites and investigating its relationship with the failure rate of bonding brackets in the same patients.

Clinical trial with two groups, randomized, on 56 patients. MATLAB software will be used for randomization.

This RCT will be conducted on 56 orthodontic office patients, immediately after completing their orthodontic treatment. Before starting the work, an informed consent will be obtained. We will use the ready-made American orthodontic retainer as a fixed retainer. We apply one of the two types of composite (Flowable and Gradia) according to a simple randomization process in the mandible of each patient (from canine to canine) for bonding the fixed retainer to the teeth. In each visit, the location of the failure of the fixed retainer will be recorded for each patient. Blinding will be done only in the statistical analysis phase.

Inclusion criteria: Orthodontic patients whose Mandible needs a canine to canine fixed retainer and who have just finished their orthodontic treatment. The age range of patients is between 15 and 25 years. Exclusion criteria: Patients with gastrointestinal reflux, patients whose mandibular anterior teeth have undergone RCT and the lingual surface of the tooth has been restored, patients whose saliva level is too low. Note: Patients who have plaque or stain on the lingual surface of their mandibular anterior teeth will be included in the study, provided that they are referred for SRP one month before the de-bonding of brackets.

Group 1- Gradia composite Group 2- Flowable GC Composite

1- The rate and location of failure of the fixed retainer 2- Bracket bonding failure rate 3- Determining clinical working time with two types of composite

There are 70 fixed orthodontic patients whose orthodontic treatment has been completed in an ideal way according to the orthodontist and who are ready to enter the study. Considering the sample size that will be 56 patients, out of 70 people, 56 people should be selected with the same probability of being selected (uniform distribution and individual randomization unit) (simple randomization sampling was used and how Creating a random sequence = using RAND function of MATLAB software.) With the sealed envelope tool, we will distribute 70 envelopes, 56 envelopes containing paper with the words "entry into the study" and 14 envelopes containing paper with the word "not entering the study" among 70 patients by the team of office secretaries. Among these 56 selected people, again with the sealed envelope tool, we divide the patients into two groups (first group: with Flowable composite and second group: with Gradia composite) with 1/1 allocation by simple randomization method. (simple randomization is used and how to make a random sequence = using RAND function of MATLAB software) For allocation concealment, we use a team of office secretaries who have no knowledge of the writings inside each of the opaque sealed envelopes written by us.