Garnering positive feedback and support across various literature, photobiomodulation can serve as an effective aid to help patients with reduced pain and discomfort during treatment.
By Dr Kevin Ng and Dr How Kim Chuan
Orthodontic tooth movements cause pain and discomfort. It also takes a long time to complete, the average treatment time being usually two to three years to achieve satisfactory results. These factors have been hindering patients from seeking treatment. To avoid long term suffering and to enhance patient co-operation and compliance, Photobiomodulation (PBM) offers the possibility of shortening treatment times. Although different clinicians hold different views regarding the application of PBM to influence orthodontics effects and outcomes, a case is reported here with satisfactory patient feedback and acceptable clinical outcome. The PBM device was used contained 42 LED cores that produced 828nm wavelength light and stimulate 4mins on each arch daily. It was found that 50% of the treatment time for the entire Invisalign course reported improved results with no pain.
The PBM device
The bite plane device consists of 42 LED cores and a power input of 2.1V. The current of each LED core is 30mA. The LED Cores produced 42,855nm wavelengths to stimulate the target sites. The energy absorbed after four minutes per arch was 248 joules. The manufacturer claimed that PBM could enhance the biology of the treatment area and improve the healing of bone and soft tissues and further enhance tooth movement.
A male patient CST, aged 20, was presented with Class I Molars, moderate anterior crowding of upper and lower arches, and rotation of 12, 23, 33 and 43. There was a lower mid-line shift to the left about 2mm, in addition to an overjet of 1mm, and an overbite of 3mm.
The patient did not want an extraction and requested the shortest possible time to finish the treatment. An iTero scanning was performed, and arch expansions were designed to improve the arches form to create spaces for alignments. Forty-five sets of aligners were prepared and treatment time was to be about a year, with one aligner each week.
PBM lights were prescribed, and two aligners were used for each week. The 45 aligners should be finished wearing by 23 weeks. The PBM device was applied for four minutes daily on each arch, and the patient was advised to return to the clinic monthly to check and ensure fittings. The patient was to record the degree of pain or discomfort monthly in the given form during aligner treatment. The feedback pain scores were rated two to three for the whole period. Orthopantomograms (OPGs) were taken before and after treatment and no root absorption occurred.
Surgical corticotomy was used to accelerate orthodontic tooth movement before the application of PBM. However, post-operative pain and complications were concerns to the patient.
In 2013, Kau assessed 73 patients and 17 controls fitted with traditional orthodontic brackets and wires and treated with 850nm wavelength, near-infrared light with a power density of 60mW/cm2 for 20-30 minutes per day. He observed that PBM achieved clinically significant accelerated tooth movements compared to the control group.
Lao proposed PBM as a non-invasive stimulation of the dentoalveolar complex with mitochondrial adenosine triphosphate (ATP) production at the mitochondrial cells. Due to the increased level of metabolic activity, ATP is increased at a localised level. Infrared light doubles cytochrome oxidase levels, mediating ATP production. Higher ATP availability accelerates cell turnover, resulting in a faster remodelling process and tooth movement. A 1.12mm movement per week for the PBM group was observed compared to 0.49mm in the control group13.
The mechanism of PBM is due to certain biological wavelengths elicited by the LED cores, generating a therapeutic effect at the cellular level. The photon source after LED produced favourable effects both in animal3 and human clinical studies12, 14, 15. The early clinical trial started with pain control, tooth movement acceleration, and increase bone remodelling and quality. Recently, this therapeutic technology had reported success in the improvement of mini-screw stability, temporomandibular disorders (TMD) disorders, root resorption, bone consolidation during maxillary expansion and distraction osteogenesis. As it was easy to operate and non-invasive, it became widely adopted for clinical use. Shan et al in 2021 subsequently found that PBM had a promising effect on post-orthodontic root resorption rehabilitation1.
Brawn et al in 2017 investigated the use of Biolux LED phototherapy daily for 21 days on an extracted socket with hydroxyapatite (HA) grafting. They found there were accelerated bone healing in the phototherapy-treated HA socket graft. This may provide faster implant osseointegration and healing compared to the control group17.
Ekizer et al in 2016 studies found PBM had the potential of accelerating tooth movement and had a positive effect on mini-screws (4,9) and these results were agreed by AlShahrani et al in 2019. They found there was a statistically significant difference between PBM therapy compared to a non-stimulated group with a mean difference of 0.598. It was proposed that the action of LPT IL-1B attracted leucocytes and stimulated fibroblasts, endothelial cells, osteoclasts, causing the effects9.
In another study, Ozturk in 2020 found PBM applications displayed inhibitory and reparative effects on OIIRR by modulating the RANKL and COX-2 expression levels. Resorption lacunae volume (p & lt; 0.001), resorption lacunae numbers (p & lt; 0.05), and percentage of the resorption (PR) lacunae (p & lt; 0.001) – these levels decreased with PBM applications when compared with the positive control groups. They also found the effects of the different wavelengths were similar7.
Sfondrini et al in 2020 studied the pain experience on subjects with banded maxillary first molars. Each molar received one session of PBM treatment on two buccal and two palatal points. In the trial group, PBM treatment showed decreased pain compared to the control group11.
Reis et al in 2021 suggested that during orthodontic tooth movement, cytokines were released in the gingival crevice, affecting bone remodelling. PBM stimulations increased the levels of IL-1β, IL-8, OPN, and PGE2 LLLT was statistically related to an increase of IL-1β levels10.
Abellán in 2021 used an intraoral scanner and cone-beam computed tomography (CBCT) to study molar intrusion using a mini screw as anchorage. Again, they found the technique was effective in accurately monitoring the intrusion distance (p > 0.05). CBCT records allowed volumetric evaluation of the root resorption process, and it was found to be less in the PBM group. (5) They also suggested that the ‘’application of PBM may provide better periodontal records and lower progression of root resorption at the expense of little lower intrusion distance and velocity’’5.
Finally, Caccianiga in 2022 reported 30 patients treated with rapid palatal expansion. The pain was significantly lower in the experimental group16. PBM was used in orthodontics together with anchoring TAD micro-screws as stability. After 60 days post-treatment, significantly higher stability was noted in the PBM group, and the authors had concluded that application of the 808nm diode laser increased micro-implant stability clinically. PBM also reduced the pain felt by patients2.
With the updated information suggested above, it is possible to apply PBM safely to assist the orthodontic patient and even to improve treatment time and outcome for patients who have received implant treatments. The findings here suggest that intraoral PBM could be used to decrease alignment treatment time and pain/discomfort, as well as encourage bone formation, promoting bone healings and osseointegration of dental implants. However, due to research limitations, a further extensive study by multi-centred, randomised clinical trials is suggested.
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