Effect of low-level laser therapy on dental root cementum remodeling in rats

Impact of intraoral non-pharmacological non-surgical adjunctive interventions on orthodontically induced inflammatory root resorption in humans: A systematic review

BACKGROUND

The current systematic review aimed to assess the impact of intraoral non-surgical non-pharmacological adjunctive interventions on orthodontically induced inflammatory root resorption (OIIRR).

SEARCH METHODS

Search without restrictions was performed up to November 2020 in three electronic databases (Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE) for randomized controlled trials (RCTs), prospective and retrospective non-randomized studies. The ROB 2.0 tool was used to assess the quality of the included RCTs, and the ROBINS-I tool was applied to non-randomized clinical studies. The strength of evidence was ranked using GRADE.

RESULTS

Three hundred and sixteen records were initially retrieved. A total of 10 studies, with 236 patients, were finally considered. These studies assessed the effects of mechanical vibration (low-frequency and high-frequency), low-intensity pulsed ultrasound (LIPUS), low-level laser therapy (LLLT) and photobiomodulation (light-emitting devices (LED). While the low-frequency vibration and LED do not seem to affect OIIRR, OIIRR has been reported to be reduced in high-frequency vibration, and LIPUS-treated teeth (differences may not likely be considered clinically relevant). The potential positive effect of LLLT on OIIRR is still debatable. Overall, the existing evidence suggests that the amount of OIIRR observed while using these interventions with traditional orthodontic treatment was not more than that was observed without it.

CONCLUSIONS

Based on a very low level of confidence, it seems that intraoral non-pharmacological non-surgical adjunctive interventions do not affect the amount of OIIRR either positively or negatively to a clinically relevant degree when compared to what is seen with conventional orthodontic treatment alone.

The effect of low-level laser therapy on orthodontically induced root resorption: a pilot double blind randomized controlled trial

Background

The effect of low-level laser therapy (LLLT) on accelerating orthodontic tooth movement has been extensively studied; however, there is limited knowledge on the use of LLLT on orthodontic root resorption.

Objective

To investigate the effect of LLLT on orthodontically induced inflammatory root resorption (OIIRR) and to compare the difference between pulsed and continuous LLLT on OIIRR.

Trial design

Double-blind, single-centre 3-arm parallel split-mouth randomized controlled trial.

Participants

Twenty adolescent patients who required bilateral maxillary first premolar (MFP) orthodontic extractions were recruited from the Sydney Dental Hospital between October 2014 and December 2014.

Intervention

All MFPs were tipped buccally for 28 days to induce OIIRR. The experimental premolars (n = 20) received LLLT and the control premolars (n = 20) received placebo-laser on days 0, 1, 2, 3, 7, 14, and 21. Ten experimental premolars received LLLT via continuous delivery and 10 received pulsed delivery.

Laser parameter

AlGaAs diode laser of 808 nm wavelength, 0.18 W power, 1.6 J per point, and duration of 9s for continuous mode and 4.5 s for pulsed mode.

Outcome

The difference in root resorption crater volume between LLLT and placebo-laser and continuous or pulsed laser delivery after 28 days.

Randomization

Randomization was computer-generated, with allocation concealment by opaque sequentially numbered sealed envelopes.

Blinding

The participants and operator were blinded.

Results

Eighty-eight patients were screened and 20 patients were randomized. Forty premolars were analysed. LLLT resulted in 23 per cent less root resorption compared to the placebo (P = 0.026). Pulsed laser delivery resulted in 5 per cent less root resorption than continuous; however, this was not statistically significant (P = 0.823). No harm was observed.

Conclusion

Teeth treated with LLLT had less total root resorption than placebo-laser. Furthermore, there was minimal difference between pulsed or continuous delivery of LLLT.

Trial Registration

Clinical Trials Registry (ACTRN12616000829415).

Protocol

The protocol was not published before trial commencement.

Physical properties of root cementum: Part 27. Effect of low-level laser therapy on the repair of orthodontically induced inflammatory root resorption: A double-blind, split-mouth, randomized controlled clinical trial

INTRODUCTION

The purpose of this 2-arm-parallel split-mouth trial was to investigate the effect of low-level laser therapy (LLLT) on the repair of orthodontically induced inflammatory root resorption (OIIRR).

METHODS

Twenty patients were included in this study, with 1 side randomly assigned to receive LLLT, and the other side served as a sham. Eligibility criteria included need for bilateral maxillary first premolar extractions as part of fixed appliance treatment. OIIRR was generated by applying 150 g of buccal tipping force on the maxillary first premolars for 4 weeks. After the active force was removed, the teeth were retained for 6 weeks. LLLT commenced with weekly laser applications using a continuous beam 660-nm, 75-mW aluminum-gallium-indium-phosphorus laser with 1/e² spot size of 0.260 cm², power density of 0.245 W/cm², and fluence of 3.6 J/cm². Contact application was used at 8 points buccally and palatally above the mucosa over each tooth root for 15 seconds with a total treatment time of 2 minutes. After 6 weeks, the maxillary first premolars were extracted and scanned with microcomputed tomography for primary outcome OIIRR calculations. Subgroup analysis included assessment per root surface, per vertical third, and sites of heaviest compressive forces (buccal-cervical and palato-apical). Randomization was generated using www.randomization.com, and allocation was concealed in sequentially numbered, opaque, sealed envelopes. Blinding was used for treatment and outcome assessments. Two-tailed paired t tests were used to determine whether there were any statistically significant differences in total crater volumes of the laser vs the sham treated teeth.

RESULTS

Total crater volumes were 0.746 mm³ for the laser treated teeth and 0.779 mm³ for the sham. There was a mean difference of 0.033 ± 0.39 mm³ (95% CI, -0.21 to 0.148 mm³) greater resorption crater volume in the sham group compared with the laser group; this was not statistically significant (P = 0.705). No harm was observed.

CONCLUSIONS

No significant difference was found between LLLT and sham control groups in OIIRR repair.

Craniofacial Wound Healing with Photobiomodulation Therapy: New Insights and Current Challenges

The fundamental pathophysiologic response for the survival of all organisms is the process of wound healing. Inadequate or lack of healing constitutes the etiopathologic basis of many oral and systemic diseases. Among the numerous efforts to promote wound healing, biophotonics therapies have shown much promise. Advances in photonic technologies and a better understanding of light-tissue interactions, from parallel biophotonics fields such as in vivo optical imaging and optogenetics, are spearheading their popularity in biology and medicine. Use of high-dose lasers and light devices in dermatology, ophthalmology, oncology, and dentistry are now popular for specific clinical applications, such as surgery, skin rejuvenation, ocular and soft tissue recontouring, and antitumor and antimicrobial photodynamic therapy. However, a less well-known clinical application is the therapeutic use of low-dose biophotonics termed photobiomodulation (PBM) therapy, which is aimed at alleviating pain and inflammation, modulating immune responses, and promoting wound healing and tissue regeneration. Despite significant volumes of scientific literature from clinical and laboratory studies noting the phenomenological evidence for this innovative therapy, limited mechanistic insights have prevented rigorous and reproducible PBM clinical protocols. This article briefly reviews current evidence and focuses on gaps in knowledge to identify potential paths forward for clinical translation with PBM therapy with an emphasis on craniofacial wound healing. PBM offers a novel opportunity to examine fundamental nonvisual photobiological processes as well as develop innovative clinical therapies, thereby presenting an opportunity for a paradigm shift from conventional restorative/prosthetic approaches to regenerative modalities in clinical dentistry.