Condition category
Oral Health
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Malocclusion is a problem in the way the upper and lower teeth fit together when biting or chewing. Orthodontic treatment can be used to improve the appearance, position and function of the teeth. In the last few decades increasing numbers of adults have sought orthodontic treatment and expressed a desire for better looking and more comfortable alternatives to traditional metal braces (often referred to as “train tracks”). Clear aligners, also known as “invisible braces”, are removable retainers which apply pressure to teeth, pushing them into the correct position. Many adults choose to use this type of appliance because they are made of a clear material, which make them very difficult to notice. They are also considered to be beneficial for good oral hygiene as they can be removed while eating and during tooth brushing. Previous studies have suggested that the movement of teeth when people use clear aligners is different to the movement of teeth seen with traditional braces, which put continuous pressure against teeth. This study aims to examine the mechanisms of tooth movement on a molecular level, by examining the biochemical make-up of the fluid found along the gum line (gingival crevicular fluid) in patients using traditional braces and clear aligners.

Who can participate?
Adults suffering from malocclusion.

What does the study involve?
Participants are randomly allocated to one of two groups. Participants in the first group are treated using traditional braces. Participants in the second group are treated using clear aligners. For participants in both groups, before treatment and then after treatment at 1 hour, 7 days and 21 days, samples of fluid from the gum line are taken using special paper strips, which are tested in the laboratory for any chemical markers of tooth movement.

What are the possible benefits and risks of participating?
Participants will benefit from correction of their malocclusion, regardless of which technique is used. There are no risks expected for those taking part in the study.

Where is the study run from?
Dental School, University of Torino (Italy)

When is the study starting and how long is it expected to run for?
May 2014 to April 2016

Who is funding the study?
Align Technology (USA)

Who is the main contact?
Dr Andrea Deregibus

Trial website

Contact information



Primary contact

Dr Andrea Deregibus


Contact details

CIR Lingotto Dental School
University of Torino
via Nizza 230
+39 11 633 1514

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Bio-markers of orthodontic tooth movement in gingival crevicular fluid of patients undergoing treatment with clear aligners or fixed appliances


Study hypothesis

The aim of this study is to find out if the bone remodeling induced by Invisalign aligners significantly different from the one induced by self-ligating appliances.

Ethics approval

Ethics Board of The Health And Science City of Turin (Comitato Etico Interaziendale A.O.U. Città della Salute e della Scienza di Torino), 10/04/2015, ref: 373/2015

Study design

Single-centre randomised parallel trial

Primary study design


Secondary study design

Randomised parallel trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet.




The selected subjects will be randomly allocated into two groups (random number list software generated) accordingly to the following treatment protocol:

Group 1: Fixed Appliance group (FA) with 10 subjects who will be treated consecutively with traditional brackets at the Department of Orthodontics of the Dental School of the University of Torino.

Group 2: Clear Aligners group (CA) with 10 subjects who will be treated consecutively with clear aligners at the Department of Orthodontics of the Dental School of the University of Torino.

GCF samples will be collected using periopaper strips (Harco, Tustin, Calif). Samples will be collected at the mesiobuccal and mesiolingual sites of control and test teeth at baseline, at 1 hour, at 7 days, and 21 days after placement of the appliances. Teeth will be isolated with cotton rolls, cleaned of plaque deposits, and dried gently with air before paper strips will be applied 1 mm subgingivally for 30 seconds. The volume of the sample on the paper strips will be measured using a calibrated Periotron 8000 (Harco). The readings from the Periotron will be converted to an actual volume (microliters) by reference to the standard curve calibrated with human serum.

Intervention type



Drug names

Primary outcome measures

Cytokine concentration will be determined from GCF samples using titration and centrifugation at baseline, 1 hour, 7 days and 21 days.

Secondary outcome measures

Identification of the most biologically efficient technique among fixed appliance and clear aligners by analysing concentrations of Interleukin 1-beta, TGF-beta, RANKL, OPG and OPN in GCF at baseline, 1 hour, 7 days and 21 days.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Dentoskeletal Class I malocclusion (Witts appraisal)
2. Mild crowding (mean crowding 6 mm)
3. Permanent dentition
4. Vertebral maturation as assessed on lateral cephalograms more advanced than CS4 (postpubertal)

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Smokers
2. Have gingivitis
3. Have probing pocket depths ≥4 mm
4. Have loss of clinical attachment ≥2 mm in the selected or adjacent teeth
5. Had taken anti-inflammatory or antibiotic medications within the previous 6 months

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Dental School, Department of Orthodontics
University of Torino via Nizza 230

Sponsor information


University of Torino (Italy)

Sponsor details

CIR Lingotto Dental School
Via Nizza 230
+39 11 633 1514

Sponsor type

Hospital/treatment centre



Funder type


Funder name

Align Technology

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Planned publication of one or more papers, reporting the protocol and the results of the study in 2016. The dissemination of the results will be performed also with the presentation of scientific posters or oral communications during orthodontic Congresses in 2016.

Intention to publish date


Participant level data

Available on request

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes