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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
The effects of laser therapy on orthodontic root resorption and pain management: A pilot study
Scientific title
The effect of low-level laser therapy compared to sham laser on orthodontically induced root resorption and pain in adolescent patients. A double-blinded split-mouth randomized controlled trial.
Secondary ID [1] 289491 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Orthodontically induced inflammatory root resorption 299187 0
Orthodontic pain 299188 0
Condition category
Condition code
Oral and Gastrointestinal 299193 299193 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon
Anaesthesiology 299242 299242 0 0
Pain management

Study type
Description of intervention(s) / exposure
Non-invasive low-level laser therapy using 808nm diode laser, energy per point 0.8J total power: 0.18W.

Participants will have partial braces placed on their upper back teeth, and they will attend the clinic 7 times during a 4 week study period for the laser to be applied, then on the 8th visit (day 28) the braces are removed and the upper first premolars will be extracted.

The study will end here and the patient will then continue normal orthodontic as needed.
Which will include full upper and lower braces and the patient will continue with comprehensive orthodontic treatment- alignment, levelling, space closure and detailing. The duration of orthodontic treatment is dependent on each patients individual need. They are no longer enrolled in the study at this point.

The study period is only 28 days.

The low level laser therapy (LLLT) and sham laser is applied daily for the first 4 days of the study period, then weekly for 3 weeks. Laser and sham are applied on Day 0, 1, 2, 3, 7, 14, 21. The first appointment (day 0) takes 30 mins to place the braces and administer the laser (40s per side (total 80s) and visual analogue scale (VAS) to assess the pain. Then each subsequent laser session takes 40s per side (total 80s) each appointment is 5 minutes long to check on the braces and administer the laser and VAS.

A qualified laser dentist administers the laser treatment

The laser (for photobiomodulation) to accelerate orthodontic tooth movement is applied after the braces are placed and during buccal tipping of the upper first premolar. Laser therapy ceases 1 week prior to tooth extraction

The laser is applied along the first premolar root, at 4 points along the premolar root (mesial and distal of the crystal, mid root and apex) - in a shape of a mercedes sign.
The laser is applied on both the buccal and palatal surfaces i.e. 8 exposure per tooth

28 days after the braces are placed, they are removed and the premolar tooth is extracted.

Adherence is strictly monitored, each patient is given a timetable prior to starting the trial to ensure they can attend all 8 sessions, and register of attendance is always taken. If a patient misses one appointment they are excluded from the study, although their orthodontic treatment will continue as per normal.
Intervention code [1] 295077 0
Treatment: Devices
Comparator / control treatment
Split mouth study, one side is experiment low-level laser and the other side is the control side where placebo/sham laser is used

Sham laser is administered using the same machine, but a piece of black absorbent paper is placed inside the laser (behind the tip) to block the laser beam. The laser is on, and makes the same sound but the beam is blocked.

Both the sham and actual laser beam is invisible to the naked eye so both the clinician and participant is blinded during this trial. As one dentist is the assistant and blinds the laser prior to each application.
Control group

Primary outcome [1] 298674 0
Volume of orthodontically induced inflammatory root resorption craters

Samples are scanned with SkyScan 1172 desktop x-ray micro-tomograph system (SkyScan, Aartselaar, Belgium) and images are reconstructed with NRecon (Version 1.4.2; Skyscan, Aartselaar, Belgium)

Specifically designed software - NRecon (Version, Skyscan, Aartselaar, Belgium) reconstructed the image data from the SkyScan. This program utilises a modified Feldkamp cone beam algorithm to produce slice by slice axial reconstruction. The settings for NRecon were standardized for all of the images. The reconstructed slices were saved in 16-bit tagged image file format (TIFF) format.

Root resorption crater analysis was performed using the imaging software program Fiji along with a custom macro Enigma. Each image slice needs to be converted to a binary image (black and white) prior to crater calculation. All of the axial slices of the image stack for each specimen are manually examined for resorption craters.

Once a crater is identified, the crater is selected with a clipping tool and duplicated into its own image sequence to allow Enigma to calculate the individual volume of each crater in cubic millimetres. All measurements are carried out by one operator (D.N.) to reduce error and bias. The craters are grouped 1) according to their location on the root surface e.g. buccal, palatal, mesial or distal; and 2) according to their location in the vertical plane e.g. apical, middle or cervical. The vertical location is determined by measuring the total length of the root from the CEJ to the apex and dividing it into equal thirds. Total root resorption volume is also recorded for each tooth.
Timepoint [1] 298674 0
28 days post-commencement of orthodontic force application (i.e. braces placed) and laser intervention
Secondary outcome [1] 324940 0
Amount of orthodontic pain using visual analog scale 0-100 on day 0 (at 0, 4, 6 hours after braces are placed then also on day, 1, 2, 3, 7, 14, 21 before and after laser is applied.
Timepoint [1] 324940 0
Post commencement of orthodontic force application (i.e Day 0 (at 0, 4, 6 hours after braces are placed then also on day, 1, 2, 3, 7, 14, 21 before and after laser is applied.

Key inclusion criteria
Patient in permanent dentition must not have had any previous orthodontic treatment but requires orthodontic treatment now,

They must have no pain/no orthodontic treatment at the beginning of the study.

They must need bilateral maxillary first premolar extractions for orthodontic purposes to be included in the study.

Apexification completed,

Similar degree of minimal crowding on each side of the maxillary arch;
Minimum age
13 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
No previous orthodontic or orthopaedic treatment;

No craniofacial anomaly present;

No previous reported or observed dental treatment of the maxillary canines;

No history of trauma, bruxism or parafunction;

No past and present signs and symptoms of periodontal disease;

No significant medical history or medication that would adversely affect the development or structure of the teeth and jaws and any subsequent tooth movement.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
sealed opaque envelops by assistant dentist who also did the blinding of the laser
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation i.e. computerised sequence generation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Paired T test
Multiple linear regression models

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 6000 0
Sydney Dental Hospital - Surry Hills
Recruitment postcode(s) [1] 13422 0
2010 - Surry Hills

Funding & Sponsors
Funding source category [1] 293859 0
Name [1] 293859 0
Australian Society of Orthodontists Foundation for Research and Education
Address [1] 293859 0
ASO Secretariat
P.O. Box 543
Country [1] 293859 0
Primary sponsor type
Doreen Ng
Sydney Dental Hospital
Orthodontic Department
Level 2
2 Chalmers St
Surry Hills, 2010
Secondary sponsor category [1] 292689 0
Name [1] 292689 0
Address [1] 292689 0
Country [1] 292689 0

Ethics approval
Ethics application status
Ethics committee name [1] 295283 0
Royal Prince Alfred Hospital Ethics Committee
Ethics committee address [1] 295283 0
Research Development Office
Royal Prince Alfred Hospital
Missenden Rd
Camperdown NSW 2050
Ethics committee country [1] 295283 0
Date submitted for ethics approval [1] 295283 0
Approval date [1] 295283 0
Ethics approval number [1] 295283 0
X140200. HREC/14/RPAH/263

Brief summary
The purpose of this study is to investigate the effectiveness of low-level laser therapy in the management of orthodontic pain during orthodontic therapy and to see if it affects root resorption of teeth. The findings from this study will be compared to other related studies performed previously. By applying pain-free laser therapy on one side next to a tooth we hope to examine its effect on root resorption. This will increase our quality of care and help prevent this damage to patients’ teeth during treatment.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 66610 0
Dr Doreen Ng
Address 66610 0
Sydney Dental Hospital
Orthodontic Department
Level 2
2 Chalmers St
Surry Hills, 2010
Country 66610 0
Phone 66610 0
Fax 66610 0
Email 66610 0
Contact person for public queries
Name 66611 0
Dr Doreen Ng
Address 66611 0
Sydney Dental Hospital
Orthodontic Department
Level 2
2 Chalmers St
Surry Hills, 2010
Country 66611 0
Phone 66611 0
Fax 66611 0
Email 66611 0
Contact person for scientific queries
Name 66612 0
Dr Doreen Ng
Address 66612 0
Sydney Dental Hospital
Orthodontic Department
Level 2
2 Chalmers St
Surry Hills, 2010
Country 66612 0
Phone 66612 0
Fax 66612 0
Email 66612 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary