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
Dr Andrea Deregibus
CIR Lingotto Dental School
University of Torino
via Nizza 230
+39 11 633 1514
Bio-markers of orthodontic tooth movement in gingival crevicular fluid of patients undergoing treatment with clear aligners or fixed appliances
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 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
Single-centre randomised parallel trial
Primary study design
Secondary study design
Randomised parallel trial
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.
Primary outcome measure
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 (if study stopped)
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)
Target number of participants
Participant exclusion criteria
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
University of Torino (Italy)
CIR Lingotto Dental School
Via Nizza 230
+39 11 633 1514
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
Basic results (scientific)