Dentoskeletal effects of clear aligners used to distalize maxillary molars in adult patients
| ISRCTN | ISRCTN66553029 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN66553029 |
| Protocol serial number | ATRA2014 |
| Sponsor | University of Torino (Italy) |
| Funder | Investigator initiated and funded |
- Submission date
- 23/10/2015
- Registration date
- 12/11/2015
- Last edited
- 18/04/2016
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Digestive System
Plain English summary of protocol
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)
Contact information
Scientific
Via Nizza 230
Italy
10126
Italy
 ORCID ID |
0000-0002-5675-3234 |
|---|---|
| Phone | +39 (0)11 1950 7750 |
| tcastroflorio@me.com |
Public
Via Nizza 230
Torino
10126
Italy
| Phone | +39 (0)11 633 1514 |
|---|---|
| andrea.deregibus@unito.it |
Study information
| Primary study design | Observational |
|---|---|
| Study design | Multicentre retrospective observational trial |
| Secondary study design | Case series |
| Study type | Participant information sheet |
| Scientific title | Dentoskeletal effects of maxillary molars distalization with aligners in adult patients: a retrospective observational trial |
| Study objectives | The study was conducted in order to test the hypothesis that maxillary molar bodily distalization is not achievable with aligners. |
| Ethics approval(s) | Ethics approval pending - to be submitted to the ethics board of the City of Health and Science of Torino, Italy in November 2015 |
| Health condition(s) or problem(s) studied | 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 / device / biological / vaccine name(s) | |
| Primary outcome measure(s) |
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. |
| Key secondary outcome measure(s) |
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. |
| Completion date | 21/09/2015 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | All |
| Target sample size at registration | 30 |
| Key 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 |
| Key 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 |
| Date of first enrolment | 01/04/2015 |
| Date of final enrolment | 08/04/2015 |
Locations
Countries of recruitment
- Canada
- Italy
Study participating centres
Canada
Italy
Lingotto Dental School
10128
Italy
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Available on request |
| IPD sharing plan |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Results article | results | 01/03/2016 | Yes | No | |
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
Editorial Notes
18/04/2016: Publication reference added.
