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Trial registered on ANZCTR

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

Titles & IDs
Public title
The effect or LLLT (low level laser therapy) on repair of root resorption undergoing bilateral first pre-molar extraction.
Scientific title
The effect or LLLT (low level laser therapy) on repair of root resorption undergoing bilateral first pre-molar extraction.
Secondary ID [1] 289251 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Root resorption (related to orthodontic treatment) 298827 0
Tooth crowding 298880 0
Condition category
Condition code
Oral and Gastrointestinal 298888 298888 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon

Study type
Description of intervention(s) / exposure
Phase 1: orthodontic tooth movement (Duration 4 weeks)
1) Orthodontic brackets bonded to the upper first permanent molar and first premolar teeth.
2) 150g buccally directed force, applied bilaterally to the first premolars to achieve buccal tipping. 4 weeks of force application:
*Using a 0.017” x 0.025” TMA (Ormco, CA) spring.
*Force magnitude measured to the nearest gram with a strain gauge (Dentaurum, Germany).

Phase 2: Removal of orthodontic force, Initiation of rest period, laser application (intervention) on experimental side, sham laser (no power) on control side. (Duration 6 weeks)

1) Orthodontic force is ceased
2) A fixed retainer constructed of 0.018” stainless steel will be bonded to the teeth to hold them passively in place.
3) During this period, laser will be applied to randomly assigned experimental side whilst the contralateral side serving as a control will receive the ‘sham’ laser.
4) Laser application - Experimental side. (660nm AlGaInP Laser Dental Probe, Thor Photomedicine Ltd, ARTG: 197699).

*6 exposures per session. This comprises 3 points along root of the tooth (crestal, mid root, apex) for each of the buccal and palatal aspects of the tooth.
* Each LLLT exposure is with a wavelength within the visible spectrum (660 nm). (Irradiance of 0.764W/cm-2 for 7 seconds which equals ~ 5.4J/cm-2 per exposure.).
*Laser sessions (once per week) for 6 weeks. This was determined based on convenience to the patient and attempting to be clinically applicable.
*Sham laser application on control side – no energy output (Sham setting on laser unit).

Each laser dose will be 7 seconds. 6 doses will be approximately 42 seconds in total. This compromises the total active time the laser will be used per session.

The approximate time of each laser appointment will be 15 minutes, however, the total active time regarding laser exposure is approximately 42 seconds as mentioned above.

An orthodontic registrar will be administering the laser dosages.

Strategies for compliance would be attendance at laser appointments.

Phase 3: Completion of rest period, extraction of first premolars for micro-ct study (1 visit for the patient).
4) Bilateral extraction of first premolars ~6 weeks after commencement of rest/healing phase.
*Analysis of teeth at Sydney Dental Hospital using a Micro-CT scanner.
*Amount of root resorption repair with and without laser to be compared
Intervention code [1] 294795 0
Treatment: Devices
Comparator / control treatment
Split mouth design.
Comparator will be the same tooth on the contralateral side which will receive no intervention (delivered via a sham setting on the laser which will deliver no dose to the tooth applied).
Control group

Primary outcome [1] 298357 0
Level of root resorption assessed qualitatively and quantitatively using micro-CT evaluation of the extracted teeth
Timepoint [1] 298357 0
6 weeks post commencement of laser therapy
Secondary outcome [1] 323929 0
Timepoint [1] 323929 0

Key inclusion criteria
*Need for bilateral maxillary first premolar extractions (necessitating moderate anchorage requirements) and fixed appliance treatment;
*Permanent Dentition;
*Apexification (root formation) completed;
*Similar degree of minimal crowding on each side of the maxillary arch;
Minimum age
10 Years
Maximum age
30 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
*Treatment plan that does not require extraction of upper first premolars
* previous orthodontic or orthopaedic treatment;
*craniofacial anomaly present;
*previous reported or observed dental treatment of the maxillary canines;
*history of trauma, bruxism or parafunction;
*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)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?

Intervention assignment
Other design features
Type of endpoint(s)
Statistical methods / analysis

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] 5816 0
Sydney Dental Hospital - Surry Hills

Funding & Sponsors
Funding source category [1] 293629 0
Name [1] 293629 0
Sydney University
Address [1] 293629 0
Orthodontic department,
Level 2, Sydney Dental Hospital,
2 Chalmers St,
Surry Hills,
Country [1] 293629 0
Primary sponsor type
Sydney University
Orthodontic department,
Level 2, Sydney Dental Hospital,
2 Chalmers St,
Surry Hills,
Secondary sponsor category [1] 292462 0
Name [1] 292462 0
Australian Orthodontic Society
Address [1] 292462 0
204 / 133 Alexander St Crows Nest NSW 2065
Country [1] 292462 0

Ethics approval
Ethics application status
Ethics committee name [1] 295068 0
NSW Health Human Research Ethics Committees (HRECs)
Ethics committee address [1] 295068 0
Suite 210A
RPAH Medical Centre
100 Carillon Avenue
Newtown NSW 2042
Ethics committee country [1] 295068 0
Date submitted for ethics approval [1] 295068 0
Approval date [1] 295068 0
Ethics approval number [1] 295068 0

Brief summary
Root resorption defects as a sideffect of orthodontic treatment.

The aim of this study is to compare whether a lower level laser operated in a stimulatory mode has an effect on the rate of healing of root resorption defects associate with routine orthodontic tooth movement.

The first part consists of applying buccally directed (towards the cheek) orthodontic forces to the upper 1st premolars to simulate orthodontic tooth movement. After 1 month, all force will be removed and the teeth retained passively to allow the natural process of root resorption repair following orthodontic tooth movement to occur. During this period, laser will be applied to one side of the mouth whilst a sham laser (no laser energy) will be used on the control side.

After another month, premolars on both sides of the mouth (laser treated and controls) will be extracted and analysed with a micro-ct to determine if laser has any effect on the rate of healing of orthodontic induced root resorption.

Root resorption is a significant consequence of orthodontic treatment. LLLT has been used in a biostimulatory manner in the healing of soft tissue wounds, implant related infections and in oral mucositis.
Findings may provide clinical evidence in relation to use of LLLT in the aid of repair of root resorption.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 65978 0
Dr Chun Min Ang-Khaw
Address 65978 0
University of Sydney,
Orthodontic Department,
Level 2,
2 Chalmers St,
Surry Hills,
Country 65978 0
Phone 65978 0
+61 2 9351 8314
Fax 65978 0
Email 65978 0
Contact person for public queries
Name 65979 0
Dr Chun Ang-Khaw
Address 65979 0
University of Sydney,
Orthodontic Department,
Level 2,
2 Chalmers St,
Surry Hills,
Country 65979 0
Phone 65979 0
+61 2 9351 8314
Fax 65979 0
Email 65979 0
Contact person for scientific queries
Name 65980 0
Dr Chun Ang-Khaw
Address 65980 0
University of Sydney,
Orthodontic Department,
Level 2,
2 Chalmers St,
Surry Hills,
Country 65980 0
Phone 65980 0
+61 2 9351 8314
Fax 65980 0
Email 65980 0

No information has been provided regarding IPD availability
Summary results
No Results