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 aesthetic and comfortable alternatives to conventional fixed braces. Clear aligners were introduced to answer this request. Cosmetically, invisible aligners are more appealing because they are difficult to notice, making them particularly popular among adults who wish to straighten their teeth without the use of traditional metal braces. Such aligners are also easily removed during eating and tooth brushing. However, little is known about the effects of clear aligners on the teeth and bones of adult patients treated to correct a forwarded position of the upper dental arch. The aim of this study is to find out whether it is possible to correct this type of malocclusion with clear aligners.
Who can participate?
Adult patients (over 18) treated with clear aligners for a forwarded upper dental arch
What does the study involve?
Participants undergo a profile x-ray of the head before and after their orthodontic treatment to assess the position of the teeth, jaws, skull and soft tissues.
What are the possible benefits and risks of participating?
Participants will benefit from the correction of their malocclusion with an aesthetic and comfortable appliance. There are no risks in participating in the study - a large number of patients have previously been treated with the clear aligners used in the study, and x-rays are always needed at the beginning and at the end of any orthodontic treatment.
Where is the study run from?
Two orthodontic private practices in Torino (Italy) and Vancouver (Canada), and the University of Torino (Italy).
When is the study starting and how long is it expected to run for?
March to September 2015
Who is funding the study?
Investigator initiated and funded
Who is the main contact?
Dr Tommaso Castroflorio (tcastroflorio@me.com)
Dr Andrea Deregibus (andrea.deregibus@unito.it)
Trial website
Contact information
Type
Scientific
Primary contact
Dr Tommaso Castroflorio
ORCID ID
http://orcid.org/0000-0002-5675-3234
Contact details
Via Nizza 230
Italy
10126
Italy
+39 (0)11 1950 7750
tcastroflorio@me.com
Type
Public
Additional contact
Dr Andrea Deregibus
ORCID ID
Contact details
Via Nizza 230
Torino
10126
Italy
+39 (0)11 633 1514
andrea.deregibus@unito.it
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
ATRA2014
Study information
Scientific title
Dentoskeletal effects of maxillary molars distalization with aligners in adult patients: a retrospective observational trial
Acronym
Study hypothesis
The study was conducted in order to test the hypothesis that maxillary molar bodily distalization is not achievable with aligners.
Ethics approval
Ethics approval pending - to be submitted to the ethics board of the City of Health and Science of Torino, Italy in November 2015
Study design
Multicentre retrospective observational trial
Primary study design
Observational
Secondary study design
Case series
Trial setting
GP practices
Trial type
Treatment
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Condition
Skeletal Class I or Class II malocclusion and a bilateral end-to-end class II molar relationship
Intervention
Orthodontic treatment with Invisalign aligners, composite attachments and class II inter maxillary elastics. Lateral cephalograms in habitual occlusion obtained before and after treatment of 20 Caucasian subjects were collected. For standardization purposes, the magnification was corrected to 8% for all cephalograms. The digital x-rays were stored in a computer, imported into commercial software ORISCEPH Rx3 (Elite Computer, Vimodrone, Italy), in order to perform landmark identifications and cephalometric tracings. These operations were randomly performed by one investigator blinded about the study, using a customized digitization set including 47 landmarks and 54 variables chosen from different existing and validated cephalometric analyses. The great number of variables was due to the number of analyzed teeth and to the number of analyzed crown and roots landmarks.
All the cephalograms were traced again after 3 weeks and then after 6 months. If there was a discrepancy between the three cephalograms, a new tracing was obtained by mutual agreement between the researchers involved in the protocol. Statistical analysis was performed using the R statistical package (version 3.0.1, R Core Team, Foundation for Statistical Computing, Vienna, Austria). The normality assumption of the data was evaluated with the Shapiro-Wilk test. According to this evaluation, the differences between before (T0) and after treatment (T1) were compared with the t-test. The level of significance was set at P<0.05.
Intervention type
Device
Phase
Drug names
Primary outcome measures
Maxillary molars distalization movement: on the lateral cephalograms collected before (T0) and after treatment (T1) (mean treatment time was 24.3 ± 4.2 months) crown and roots landmark were identified in order to describe the mean distalization movements on the sagittal plane as well as the vertical and the angular movements. Crowns’ centers, obtained as the midpoint between the greatest mesial and distal convexity of the crown, as well as the axis passing through mesial cusps and mesio-vestibular roots’ apex were taken as reference points of the maxillary first and second molar as seen on the cephalograms. The movements of these points at T1 with respect to T0 were considered in relation to the reference axes represented by the palatal plane (x axis) and by a perpendicular line to the palatal plane passing through the Ricketts’ Pt point (y axis). The palatal plane was used to measure vertical and angular movements, while the y axis was used to measure sagittal movements of the second molar and of the first molar.
The overall craniofacial treatment changes were evaluated by superimposing on the stable structures of the anterior cranial base according to the Structural Method (Björk A. Guide to superimposition of profile radiographs by “The Structural Method” http://www.angle-society.com/case/guide.pdf). Superimpositions were conducted digitally.
Secondary outcome measures
Central incisor retraction movement: the incisal edge point, the root apex point and the crown centre point, the midpoint of the lateral projection of the circumference formed by the root and crown conjunction, were the landmarks considered on the lateral cephalograms to describe the movement of the maxillary central incisor with respect to the reference axes described above.
On the lateral headfilms, the palatal plane/mandibular plane (PP/MP) and the SN/mandibular plane angles were evaluated as indicators of skeletal posterior vertical dimension changes.The overall craniofacial treatment changes were evaluated by superimposing on the stable structures of the anterior cranial base according to the Structural Method (Björk A. Guide to superimposition of profile radiographs by “The Structural Method” http://www.angle-society.com/case/guide.pdf). Superimpositions were conducted digitally.
Overall trial start date
18/03/2015
Overall trial end date
21/09/2015
Reason abandoned
Eligibility
Participant inclusion criteria
1. Age over 18 years old
2. Skeletal Class I or Class II malocclusion and a bilateral end-to-end class II molar relationship
3. Normodivergence on the vertical plane (SN/GoGn angle less than 37 degrees)
4. Mild crowding in the upper arch (≤ 4mm)
5. Standardized treatment protocol
6. Good compliance during the treatment (wearing aligners time: ≥20 hours per day)
7. Absence or previous extraction of the upper third molars
8. Good quality radiographs, with adequate landmark visualization and head rotation control
Participant type
Patient
Age group
Adult
Gender
Both
Target number of participants
30
Participant exclusion criteria
1. Transversal dental or skeletal discrepancies
2. Vertical dental or skeletal discrepancies
3. Extraction treatment (except for third molars)
4. Unilateral distalization
5. Signs and/or symptoms of temporomandibular disorders (TMDs) accordingly to Diagnostic Criteria for TMDs
6. Periodontal disease
7. Endodontic treatments of the maxillary molars
8. Prosthodontics rehabilitations of the maxillary molars
Recruitment start date
01/04/2015
Recruitment end date
08/04/2015
Locations
Countries of recruitment
Canada, Italy
Trial participating centre
Daher Orthostyle
BC V7V 1H9
Canada
Trial participating centre
Studio Associato Icardi Castroflorio Odontoiatri
10137
Italy
Trial participating centre
University of Torino
Orthodontics Department
Lingotto Dental School
10128
Italy
Sponsor information
Organisation
University of Torino (Italy)
Sponsor details
CIR Lingotto Dental School
Via Nizza 230
Torino
10126
Italy
+39 (0)11 633 1514
andrea.deregibus@unito.it
Sponsor type
University/education
Website
Funders
Funder type
Other
Funder name
Investigator initiated and funded
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
We would like to publish a paper reporting the protocol and the results of the study in the first quarter of 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
2016 results in: http://www.ncbi.nlm.nih.gov/pubmed/27041551