Influence of Different Nanohybrid Flowable Composite Resin on Shear Bond Strength and Dimensional Changes of Invisalign Attachments After 6 Months of Brushing

Malocclusion Clinical Trial

Official title: Influence of Different Nanohybrid Flowable Composite Resin on Shear Bond Strength and Dimensional Changes of Invisalign Attachments After 6 Months of Brushing: in Vitro Study and Randomized Clinical Trial

Status Enrolling by invitation

Clinical Trial Summary

The present study will be a single-center, split-mouth, randomized controlled clinical trial. Patients undergoing orthodontic treatment with Invisalign aligners will be enrolled after signing the informed consent. Two different flowable composite resins will be evaluated for the performing of attachments using a split-mouth design:

• group A: Filtek Supreme Flow (3M Unitek, Monrovia, Calif)

• group B: Grandioso Heavy Flow (VOCO GmbH, Cuxhaven Germany)

Digital impressions with iTero intraoral scanner will be performed; digital impressions will be performed after 3 months (T1) and 6 months (T2) from the baseline.

Digital scans will be used to assess any changes in shape and volume of the attachments per each different time frame. Each tooth will be separated from the others and superimpositions of the single tooth will be performed with ZEISS Inspect software.

After attachments placement, the clinicians will be asked to answer, on a scale from 1 to 10, to this questionnaire's questions about the two different flowable composites; each question is repeated for each composite resin.

Type of brushing (with manual or electric toothbrush) and hand of brushing will be recorded.

Clinical Trial Description

The present study will be a single-center, split-mouth, randomized controlled clinical trial. Patients willing to start Invisalign treatment or refinement phases will be recruited from the Unit of Orthodontics and Pediatric Dentistry, Section of Dentistry, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy. Each patient will sign the informed consent before participation.

The bonding procedure will be the following: isolation of the working field with the placement of a cheek retractor, enamel etching with 37% orthophosphoric acid, rinsing and drying, application of a thin layer of ScotchBond adhesive (3M Unitek, Monrovia, Calif) and light curing. Then, patient will be divided into groups A and B: in group A, attachments will be realized using Filtek Supreme Flow (3M Unitek, Monrovia, Calif) for teeth belonging to mandibular left and maxillary right quadrants, whereas in the remaining quadrants, they will be realized using Grandioso Heavy Flow (VOCO GmbH, Cuxhaven Germany. In group B, quadrants will be inverted. After the bonding of the attachments, digital impressions with iTero intraoral scanner will be performed; digital impressions will be performed after 3 months (T1) and 6 months (T2) from the baseline.

Digital scans will be used to assess any changes in shape and volume of the attachments per each different time frame. Each tooth will be separated from the others and superimpositions of the single tooth will be performed with ZEISS Inspect software.

After attachments placement, the clinicians will be asked to answer, on a scale from 1 to 10, to this questionnaire's questions about the two different flowable composites; each question is repeated for each composite resin.

Type of brushing (with manual or electric toothbrush) and hand of brushing will be recorded.

Sample size calculation was performed assuming Type I error alpha=0.05 and Type II error power = 80% for two independent study groups and a continuous primary endpoint. The primary outcome chosen was "Volumetric change". Based on the results of previous studies [Chen et al., 2021], an expected value of 1.28 was hypothesized. The expected difference between the means was supposed to be 0.44 with a standard deviation of 0.5; therefore, 20 patients were required for the study. ;

Related Conditions & MeSH terms

• Malocclusion

• NCT number: NCT06288386
• Study type: Interventional
• Source: University of Pavia
• Status: Enrolling by invitation
• Phase: N/A
• Start date: March 4, 2024
• Completion date: February 2025