Comparison of Dimensional Accuracy and Color Stability Between Direct 3D-printed and Thermoformed Retainers

N/ANot Yet RecruitingNCT07053410

Essraa hassan Hussein Mohamed30 enrolled

Overview

This study aims to compare two types of orthodontic retainers used after active treatment to maintain teeth position. The retainers are fabricated using either direct 3D-printing or thermoforming methods. The study will evaluate which method provides better dimensional accuracy (fit) and color stability over time. Adult patients who have completed their orthodontic treatment will be randomly assigned to one of three groups, each receiving a different type of retainer. The research is conducted at the Faculty of Dental Medicine, Al-Azhar University - Assiut Branch. The goal is to help orthodontists select the most reliable and durable type of retainer for long-term use.

This randomized clinical and laboratory study investigates the dimensional accuracy and color stability of orthodontic retainers fabricated using two different techniques: direct 3D printing and thermoforming. Patients who have completed active orthodontic treatment will be recruited and assigned to three groups. Group T1 will receive 3D-printed retainers, Group T2 will receive single-layer thermoformed retainers, and Group T3 will receive multi-layer thermoformed retainers…

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Orthodontic Retention Appliance Clear Orthodontic Retainers

Interventions

Direct 3D-Printed RetainerDEVICE

Orthodontic retainers fabricated using direct 3D printing technology from digital STL models. The retainers are printed with biocompatible clear resin using an additive manufacturing process.

Single-Layer Thermoformed RetainerDEVICE

Clear orthodontic retainers fabricated by thermoforming a single-layer thermoplastic sheet over a 3D printed dental model using a vacuum forming machine.

Multi-Layer Thermoformed RetainerDEVICE

Orthodontic retainers fabricated using a multi-layer thermoforming technique combining different thermoplastic materials to enhance durability and fit accuracy.

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Patients who have completed their active orthodontic treatment. * Adults aged 18 years and above. * Cooperative individuals willing to participate. * Patients with good oral hygiene and general health. * No systemic diseases that may affect treatment outcomes. Exclusion Criteria: * Smokers. * Patients with a history of poor compliance with previous orthodontic treatment. * Patients with parafunctional oral habits (e.g., bruxism). * Patients undergoing retreatment due to relapse.

Outcomes

Primary Outcomes

Mean Surface Deviation (mm) Between Retainer STL and Original STL Reference Model Assessed by 3D Superimposition After 1 Month

Dimensional accuracy will be assessed by scanning each retainer and generating an STL file. The resulting STL will be superimposed on the original digital reference STL model using best-fit alignment in 3D inspection software (e.g., Geomagic Control X). The software will calculate the mean surface deviation in millimeters (mm). Results will be reported as mean ± standard deviation for each group (3D-printed vs thermoformed).

Time frame: 1 month after retainer delivery

Secondary Outcomes

Color Change (ΔE) of Retainers Measured by Spectrophotometer Based on CIE L*a*b* System After 1 Month

Color stability will be evaluated by measuring the color of each retainer before and after intraoral use using a spectrophotometer. The color change (ΔE) will be calculated according to the CIE L\*a\*b\* color system formula. Results will be reported as mean ΔE ± standard deviation for each group. A ΔE value \>3.3 will be considered visually perceptible.