Comparing the Impact of Rubber Bands on Teeth Straightening with Clear Aligners Versus Traditional Braces: a Clinical Study (Class II)

Effects of Class II Elastics During Treatment with Clear Aligners Vs Fixed Appliance: a Randomized Clinical Trial

Aim: To analyze the inclination of lower incisors in patients with Class II malocclusion treated with elastics and clear aligners compared to a group wearing the same elastics and fixed appliance. A sample of 40 patients (19M and 21F), mean age 15.4±1.8 years, was randomly divided in two groups: Clear aligner group (CA), Fixed appliance group (FA). The subjects were selected according to inclusion criteria: full permanent dentition (excluding third molars), Class II molar relationship (2,5-4 mm), no history of orthodontic treatment.

Study Overview

• Status: Completed
• Conditions: Class II Malocclusion; IMPA Angle
• Intervention / Treatment: Device: clear aligners and elastics; Device: class 2 elastics

Detailed Description

Trial design: Prospective two-arms parallel group randomized clinical trial with 1:1 allocation ratio.

Materials and Methods: A sample of 40 patients (19M and 21F), mean age 15.4±1.8 years, was collected from the Department of Orthodontics at Policlinico "Tor Vergata" of Rome, and it was randomly divided in two groups: Clear aligner group (CA), Fixed appliance group (FA). The subjects were selected according to inclusion criteria: full permanent dentition (excluding third molars), Class II molar relationship (2,5-4 mm), no history of orthodontic treatment. Results: In the short term (T1-T0=18 months), the analysis of the results showed no statistically significant changes in all evaluated parameters. Therefore, there is no statistically significant change in the inclination of the lower incisors between the two groups.

Conclusions: The use of Class II elastics in CA group showed a better control of the lower incisors' inclination, compared to the FA group, even if the difference is not significant.

Trial registration: ClinicalTrials.gov (registration number: ..........)

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Rome, Italy, 00131
    • University of Tor Vergata

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• full permanent dentition (excluding third molars), Class II molar relationship (2,5-4 mm), no or moderate crowding (0- 3 mm) no history of orthodontic treatment.

Exclusion Criteria:

• not completed permanent dentition, skeletal Class II or dental Class II more than 4 mm, crowding more than 3 mm, subjects already treated with iother orthodontic appliances.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Class II malocclusion with clear aligners; For the groupteated with Clear Aligners (CA), the treatment provided the application of Invisalign clear aligner system and the absence of any other auxiliaries apart from Invisalign optimized attachments. Each subject was instructed to wear aligners for 22 hours per day, except during meals and oral hygiene procedures and to replace aligners once a week, always the same day of the week. Every six stages the clinician personally checked the good aligner fitting, the position of the attachments and the patient collaboration.	Device: clear aligners and elastics; For the Fixed Appliance group, the straight wire treatment included an aligning and leveling phase, achieved by using Nickel-Titanium arches (0.016/0.019 × 0.025 arc sequence) and a phase with heavier stainless steel rectangular arches (0.019 × 0.025); during this last treatment phase patients were instructed to use Class II elastics for at least 16 h/day. Pre- (T0) and post-treatment (T1) lateral cephalogram were collected from all selected patients. Treatment time was an average of 18 months (T1-T0=18 months).; Other Names: fixed appliance and elastics; Device: class 2 elastics; Class II malocclusion is the most common malocclusion, and it is one of the main reasons for people to undergo orthodontic treatment. This alteration is characterized by an improper relationship between the maxillary and mandibular arches because of skeletal or dental discrepancies or a combination of both . The treatment protocols may considerably vary depending on professional skills, malocclusion severity and patient compliance . Among all the well-known techniques, it is important to mention the Class II elastics , used to camouflage mild skeletal Class II or to treat mild to moderate Class II occlusal relationship. During the correction of Class II malocclusions by means of inter-arch elastics, special attention should be paid to the position of the lower incisors.
Experimental: Class II malocclusion with fixed appliance and elastics; For the group treated with Fixed Appliance (FA), the straight wire treatment included an aligning and leveling phase, achieved by using Nickel-Titanium arches (0.016/0.019 × 0.025 arc sequence) and a phase with heavier stainless steel rectangular arches (0.019 × 0.025); during this last treatment phase patients were instructed to use Class II elastics for at least 16 h/day. Pre- (T0) and post-treatment (T1) lateral cephalogram were collected from all selected patients. Treatment time was an average of 18 months (T1-T0=18 months).	Device: class 2 elastics; Class II malocclusion is the most common malocclusion, and it is one of the main reasons for people to undergo orthodontic treatment. This alteration is characterized by an improper relationship between the maxillary and mandibular arches because of skeletal or dental discrepancies or a combination of both . The treatment protocols may considerably vary depending on professional skills, malocclusion severity and patient compliance . Among all the well-known techniques, it is important to mention the Class II elastics , used to camouflage mild skeletal Class II or to treat mild to moderate Class II occlusal relationship. During the correction of Class II malocclusions by means of inter-arch elastics, special attention should be paid to the position of the lower incisors.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison between two different devices to solve class II dental malocclusion	A sample of 40 patients (19M and 21F), mean age 15.4±1.8 years was collected from the Department of Orthodontics at Policlinico "Tor Vergata" of Rome, from September 2023 to June 2024. The sample was randomly divided in two groups: FA group (Fixed Appliance), consisted of 20 patients (9 M, 11F) treated by straight-wire fixed appliance and Class II elastics: CA group (Clear Aligners), consisted of 20 patients (9M, 11F) treated by Comprehensive Package Invisalign® system and Class II elastics. For both FA and CA groups, the inclusion criteria were the following: full permanent dentition (excluding third molars), Class II molar relationship (2,5-4 mm), no or moderate crowding (0- 3 mm) no history of orthodontic treatment. Pre- (T0) and post-treatment (T1) lateral cephalogram were collected from all selected patients. Treatment time was an average of 18 months (T1-T0=18 months).	From enrollment to the end of treatment at 18 months

Collaborators and Investigators

• Sponsor: University of Rome Tor Vergata

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2023
• Primary Completion (Actual): June 30, 2024
• Study Completion (Actual): December 15, 2024

Study Registration Dates

• First Submitted: February 13, 2025
• First Submitted That Met QC Criteria: February 13, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 13, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Stomatognathic Diseases; Tooth Diseases; Malocclusion; Malocclusion, Angle Class II; Overbite
• Other Study ID Numbers: Ethical Commitee n. 24/23

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No