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

Effect of low-level laser therapy on en masse retraction in females with bimaxillary dentoalveolar protrusion : A single-center randomized clinical trial

BACKGROUND

Acceleration of tooth movement has gained remarkable attention during the last decade. The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) on en masse retraction of upper anterior teeth in adult women with bimaxillary dentoalveolar protrusion.

MATERIALS AND METHODS

In this two-arm parallel trial, 36 women with bimaxillary dentoalveolar protrusion were randomly divided into two equal groups. Eligibility criteria included class I Angle molar relationship, good general and oral health as well as no systemic disease or syndrome. Four temporary anchorage devices (TADs) were used in the upper and lower arches for anchorage purposes. A 0.019×0.025-inch stainless steel wire with crimped hooks just distal to the maxillary canines was inserted. Nickle titanium (NiTi) closed coil springs (200 g/side) were employed for en masse retraction following extraction of the first premolars. In the laser group (LG), retraction of the upper anterior teeth was done along with the application of LLLT on days 0, 3, 7, and 14 after extraction and then repeated biweekly until the end of retraction. Retraction was completed without LLLT application in the nonlaser group (NLG). Data concerning the rate of retraction as well as first molars and anterior positional changes were gained from digitized models and cone beam computed tomography (CBCT) scans taken just before extraction and at the end of retraction. Treatment-associated pain and root resorption were evaluated using visual analogue scale (VAS) and CBCT scans, respectively.

RESULTS

Four patients dropped out prior to follow-up. The duration of retraction was 10.125 ± 2.876 and 13.643 ± 3.455 months in the LG and NLG, respectively. The LG showed a statistically significant faster rate of en masse retraction (0.833 ± 0.371 mm/month) compared to the NLG (0.526 ± 0.268 mm/month; P ≤ 0.035). The observed root resorption was significantly less in the LG (P ≤ 0.05) with comparable pain scores in both groups.

CONCLUSIONS

Within the constraints of the parameters of the LLLT used in the current study and despite the statistically significant results on the rate of en masse retraction and the associated root resorption, LLLT did not demonstrate a clinically relevant effect that justifies its use to enhance en masse retraction.

NAME OF THE REGISTRY

Clinicaltrials.gov TRIAL REGISTRATION NUMBER: NCT05183451 DATE OF REGISTRATION: January 10, 2022, "Retrospectively registered" URL OF TRIAL REGISTRY RECORD: https://www.

CLINICALTRIALS

gov/study/NCT05183451.

Photobiomodulation therapy assisted orthodontic tooth movement: potential implications, challenges, and new perspectives

Over the past decade, dramatic progress has been made in dental research areas involving laser therapy. The photobiomodulatory effect of laser light regulates the behavior of periodontal tissues and promotes damaged tissues to heal faster. Additionally, photobiomodulation therapy (PBMT), a non-invasive treatment, when applied in orthodontics, contributes to alleviating pain and reducing inflammation induced by orthodontic forces, along with improving tissue healing processes. Moreover, PBMT is attracting more attention as a possible approach to prevent the incidence of orthodontically induced inflammatory root resorption (OIIRR) during orthodontic treatment (OT) due to its capacity to modulate inflammatory, apoptotic, and anti-antioxidant responses. However, a systematic review revealed that PBMT has only a moderate grade of evidence-based effectiveness during orthodontic tooth movement (OTM) in relation to OIIRR, casting doubt on its beneficial effects. In PBMT-assisted orthodontics, delivering sufficient energy to the tooth root to achieve optimal stimulation is challenging due to the exponential attenuation of light penetration in periodontal tissues. The penetration of light to the root surface is another crucial unknown factor. Both the penetration depth and distribution of light in periodontal tissues are unknown. Thus, advanced approaches specific to orthodontic application of PBMT need to be established to overcome these limitations. This review explores possibilities for improving the application and effectiveness of PBMT during OTM. The aim was to investigate the current evidence related to the underlying mechanisms of action of PBMT on various periodontal tissues and cells, with a special focus on immunomodulatory effects during OTM.

The Effects and Mechanisms of PBM Therapy in Accelerating Orthodontic Tooth Movement

Malocclusion is one of the three major diseases, the incidence of which could reach 56% of the imperiled oral and systemic health in the world today. Orthodontics is still the primary method to solve the problem. However, it is clear that many orthodontic complications are associated with courses of long-term therapy. Photobiomodulation (PBM) therapy could be used as a popular way to shorten the course of orthodontic treatment by nearly 26% to 40%. In this review, the efficacy in cells and animals, mechanisms, relevant cytokines and signaling, clinical trials and applications, and the future developments of PBM therapy in orthodontics were evaluated to demonstrate its validity. Simultaneously, based on orthodontic mechanisms and present findings, the mechanisms of acceleration of orthodontic tooth movement (OTM) caused by PBM therapy were explored in relation to four aspects, including blood vessels, inflammatory response, collagen and fibers, and mineralized tissues. Also, the cooperative effects and clinical translation of PBM therapy in orthodontics have been explored in a growing numbers of studies. Up to now, PBM therapy has been gaining popularity for its non-invasive nature, easy operation, and painless procedures. However, the validity and exact mechanism of PBM therapy as an adjuvant treatment in orthodontics have not been fully elucidated. Therefore, this review summarizes the efficacy of PBM therapy on the acceleration of OTM comprehensively from various aspects and was designed to provide an evidence-based platform for the research and development of light-related orthodontic tooth movement acceleration devices.

Effects of Low-Level Laser Therapy and Bracket Systems on Root Resorption during Orthodontic Treatment: A Randomized Clinical Trial

This study aimed to assess the outcomes of low-level laser therapy (LLLT) with the conventional bracket (CB) and self-ligating (SL) bracket systems on root resorption (RR) during orthodontic treatment. A total of 32 patients were included in this randomized clinical trial. All the patients were randomly divided into four individual groups (SLL: self-ligating laser, CBL: conventional bracket laser, SLNL: self-ligating non-laser, CBNL: conventional bracket non-laser). RR was measured from the cone-beam computed tomography (CBCT) radiographs which were taken at two stages of the orthodontic treatment: pre-treatment (T1) and after leveling and alignment stage (T2). Wilcoxon rank test for the comparison was conducted to compare the RR at T1 and T2 stages within each group and showed a significant difference (p < 0.05) for various variables. Mann Whitney test compared the RR in laser and non-laser groups irrespective of the bracket systems and exhibited no significant differences except the left lateral incisor. Moreover, CB and SL groups showed no significant difference in RR among any tooth. Kruskal Wallis test was performed to compare the RR among all groups which presented no significant differences. LLLT and bracket systems have no consequences on RR until the leveling and alignment stage of orthodontic treatment.

Improving Titanium Implant Stability with Photobiomodulation: A Review and Meta-Analysis of Irradiation Parameters

Objective: This analysis was designed to present a summary of available evidence that will inform practice and guide future research for photobiomodulation (PBM) after titanium implant placement procedures. Materials and methods: A systematic review was performed according to the Cochrane Collaboration and in line with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) criteria. Two investigators screened the titles and abstracts, and reviewed articles for risk of bias. Online databases searched included PubMed, Embase, Scopus, and Web of Science. Terms were specific to the effects of PBM on dental implant stability. Results: Eight hundred fifty-six studies were identified, and 15 studies fulfilled the inclusion criteria. Light sources included both laser and light emitting diode (LED) devices. Wavelengths ranged from 618 to 1064 nm. The meta-analysis concluded that all 15 published studies were able to safely apply PBM near dental implants without adverse events. Laser and LED wavelengths that reported significant results included 618, 626, 830, 940 (2 × ), and 1064 nm. Conclusions: The use of adjunctive PBM can be safely prescribed after surgical placement of titanium implants. Six groups reported statistical significance for improving implant stability (four laser diode, two LED) in wavelengths ranging from 618 to 1064 nm. The amount of time spent delivering PBM was not a variable that differentiated whether a study reported significant results.

Investigating the Effectiveness of Low-Level Laser in Reducing Root Resorption of the Upper Incisors During Intrusion Movement Using Mini-Implants in Adult Patients With Deep Overbite: A Randomized Controlled Clinical Trial

BACKGROUND

Deep bite is a common characteristic of malocclusion, and many methods are used to treat it, including mini-implants used for the intrusion of the upper incisors. Orthodontically induced inflammatory root resorption (OIIRR) is an inevitable and unexpected side effect of orthodontic therapy. However, resorption of the root could be affected by the type of tooth movement, such as intrusion. Several studies have indicated the effectiveness of low-level laser therapy (LLLT) in accelerating orthodontic movement, but studies that have evaluated the role of this laser in reducing the risk of OIIRR have been limited. This trial aimed to investigate the effectiveness of LLLT in reducing the resorption of the roots of the upper incisors during their intrusion in the context of deep bite correction.

MATERIALS AND METHODS

Thirty patients (13 males, 17 females; mean age 22.4±3.37 years) with deep overbite were recruited and allocated to the laser or the control groups. Mini-implants were inserted between the roots of the upper central incisors and the lateral incisors from the labial aspect at the gingival-mucosal junction on both sides with a force of 40 g on each side through an NiTi coil spring. A low-level laser (Ga-Al-As) with 808 nm wavelength in a continuous mode, with the parameters 250 milliwatt power output, 4 Joules/point energy density, and 16 seconds irradiation per point, was applied to the root of each of the upper incisors. The laser was applied on the first day of the upper incisor intrusion (T1), then on days 3, 7, and 14 of the first month. In the second month, the laser was applied every 15 days, adjusting the spring strength every four weeks until the end of the intrusion stage (T2), which was determined by reaching a normal overbite. As for patients in the control group, the strength of the nickel-titanium springs was adjusted every four weeks to the required strength of 40 g on each end until reaching a normal overbite.

RESULTS

There was a volumetric decrease in both groups' upper central and lateral incisors roots, and this decrease was statistically significant (P<0.001). However, the difference between the two groups was not statistically significant in each central and lateral incisor volume root (P=0.345 and 0.263 for U1 and U2, respectively). Also, both groups had a linear decrease in upper central and lateral incisors roots, which was statistically significant (P<0.001). At the same time, the difference between the two groups was not statistically significant in each central and lateral incisor root length (P=0.343 and 0.461 for U1 and U2, respectively).

CONCLUSION

The low-level laser irradiation using the current protocol did not significantly affect the amount of root resorption induced by incisor intrusion in the experimental group compared to the control group.

The influence of two photobiomodulation protocols on orthodontically induced inflammatory root resorption (a randomized controlled clinical trial)

Background

Controversial results have been reported regarding the impact of photobiomodulation (PBM) on orthodontically induced inflammatory root resorption (OIIRR). The aim of this study was to evaluate the influence of two PBM protocols, one of them requiring a high application frequency (on days 0, 3, 7, 14, then every 2 weeks), while the second requires less frequent applications (every 3 weeks), on OIIRR accompanying orthodontic treatment.

Methods

Twenty female patients were recruited for this randomized controlled trial, requiring the therapeutic extraction of maxillary first premolars, and they were randomly divided into 2 equal groups. In Group A, one side of the maxillary arch randomly received PBM on days 0, 3, 7, 14, and every 2 weeks thereafter, while in Group B, one side was randomly chosen to receive PBM every 3 weeks. The laser applied was a Diode laser with a wavelength of 980 nm, in a continuous mode. Canine retraction in both groups was carried out using closed-coil springs, delivering 150 g of force, and the force level was checked every 3 weeks, over a 12-week study period. Pre-retraction and post-retraction cone-beam computed tomography (CBCT) was done for the evaluation of OIIRR.

Results

No significant differences in the amount of OIIRR have been reported between the laser and control sides in both groups A and B. Also, no significant differences have been reported between the laser sides in both groups.

Conclusions

Photobiomodulation does not affect OIIRR, whether by increasing or decreasing its occurrence, with both laser application protocols. Therefore, it can be stated that PBM does not result in root resorption less than the commonly observed range elicited with conventional orthodontic treatment, and that it has no effect on OIIRR.

Trial registration Two Low-level Laser Irradiation Protocols on the Rate of Canine Retraction (NCT04926389), 15/06/2021—retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT04926389.

Ectopic Eye Tooth Management: Photobiomodulation/Low-Level Laser Emission Role in Root Resorption after Fixed Orthodontic Treatment

Aim: This study evaluates the role of low-level laser emission/photobiomodulation (LE/P) in quantitative measurements of root resorption (QRR). The application of LE/P performed after each orthodontic activation with four types of treatment intervention (TI) on the root resorption (RR) after fixed orthodontic treatment (FOT) of the upper arch with ectopic eye tooth/teeth [EET] was investigated. Materials and Methods: Thirty-two orthodontic patients scheduled for FOT were selected and assigned to the four groups. These were LE/P + Self ligating bracket (SLB), LE/P + Conventional bracket (CB), non-photobiomodulation (non-LE/P) + SLB and non-LE/P + CB. Standard management stages of FOT were followed in the maxilla. Each patient received a single application of LE/P labially/buccally and palatally, a total of five different points were used during each activation or appointment. The main outcome measure was QRR in maxillary anteriors before and after FOT, assessed via cone-beam computed tomography (CBCT) using 3D OnDemand software. Results: Insignificant QRR was found between before and after FOT in SLB, CLB, and LE/P, non-LE/P groups (p > 0.05). QRR in the SLB vs. CB and LE/P vs. non-LE/P group was significantly different in 11, 13, and 23 (p < 0.05). QRR in the LE/P + SLB group (p < 0.05) was significantly different in 11, 13, and 23 than that in the other groups. The most severe QRR was found on 13 (0.88 ± 0.28 mm and 0.87 ± 0.27 mm) and 23 (1.19 ± 0.14 mm and 1.16±0.13 mm) in the CB and non-LE/P group (p < 0.001). LE/P + SLB showed a highly significant superior outcome (p < 0.001) in relation to non-LE/P + CB, the QRR of 23 were 0.813 ± 0.114 mm and 1.156 ± 0.166 mm, respectively. Conclusion: Significantly higher amounts of QRR were found in EET patients after FOT treated with the CB, non-LE/P, and non-LE/P + CB system and warrant further investigation to explore potential specific causes.

The protocol of low-level laser therapy in orthodontic practice: A scoping review of literature

Low-level laser therapy (LLLT) has been widely investigated as an adjunct technique for orthodontic treatment due to photobiomodulation effect. LLLT appears to be supportive for an orthodontic practice in terms of tooth movement acceleration, pain relief, and root resorption management. The decrease in these adverse effects will enhance the compliance in orthodontic patients, which could positively impact treatment outcomes. However, there seemed to be inconsistency in the impact of LLLT as well as its laser and treatment parameters. This scoping review aimed to evaluate the impact of different irradiation parameters on tooth movement acceleration, pain relief, and root resorption as well as to construct a protocol of LLLT in orthodontic practice. The search was conducted across PubMed, Scopus, Web of Science, Embase, Google Scholar, and the reference lists of identified articles. The last search was conducted on October 10, 2021 to identify experiments in humans regarding the application of LLLT as noninvasive treatment in orthodontic practice published between 2010 and 2021. However, they were excluded if they were not clinical research, if they did not report the source of laser, or if they were not relevant to tooth movement, pain perception, and root resorption, or if they were not available in English or in full-text. Following the systematic search and selection process, 60 articles were included in this review. A majority of included articles were published in the past few years. The findings of this review supported the application of LLLT in orthodontic practice with purposes of tooth movement acceleration and pain reduction. The positive impact of LLLT on root resorption had not been clearly evident yet. As this review demonstrated heterogeneity of both laser and treatment parameters, further research should be required to ensure the effectiveness of its specific parameters in orthodontic practice.

Biomechanical and biological responses of periodontium in orthodontic tooth movement: up-date in a new decade

Nowadays, orthodontic treatment has become increasingly popular. However, the biological mechanisms of orthodontic tooth movement (OTM) have not been fully elucidated. We were aiming to summarize the evidences regarding the mechanisms of OTM. Firstly, we introduced the research models as a basis for further discussion of mechanisms. Secondly, we proposed a new hypothesis regarding the primary roles of periodontal ligament cells (PDLCs) and osteocytes involved in OTM mechanisms and summarized the biomechanical and biological responses of the periodontium in OTM through four steps, basically in OTM temporal sequences, as follows: (1) Extracellular mechanobiology of periodontium: biological, mechanical, and material changes of acellular components in periodontium under orthodontic forces were introduced. (2) Cell strain: the sensing, transduction, and regulation of mechanical stimuli in PDLCs and osteocytes. (3) Cell activation and differentiation: the activation and differentiation mechanisms of osteoblast and osteoclast, the force-induced sterile inflammation, and the communication networks consisting of sensors and effectors. (4) Tissue remodeling: the remodeling of bone and periodontal ligament (PDL) in the compression side and tension side responding to mechanical stimuli and root resorption. Lastly, we talked about the clinical implications of the updated OTM mechanisms, regarding optimal orthodontic force (OOF), acceleration of OTM, and prevention of root resorption.

Effect of photobiomodulation on external root resorption during orthodontic tooth movement - a randomized controlled trial

OBJECTIVE

The objective of the study was to compare external root resorption during orthodontic tooth movement between patients who were subjected to photobiomodulation and those who were not.

MATERIALS AND METHODS

The study was designed as a split-mouth, single-blind randomized controlled trial conducted on twenty-two orthodontic patients requiring extraction of maxillary first premolars (age group 13-30years). A buccal force was applied to all the premolars using a 0.019″×0.025″ beta-titanium cantilever spring for 28days. The test group premolars were irradiated by indium-gallium-arsenide (InGaAs) diode laser (980nm, 100mW) 0, 3, 7, 11, 15 and 28days after force application. Each premolar was irradiated at ten locations on the buccal and palatal gingiva resulting in a total energy of 10J delivered per tooth. After 28days, the root surface of all the premolars were studied for the number and volume of resorption craters using three-dimensional optical profilometry by a blinded assessor. One-sample Kolmogorov-Smirnov test was used to ascertain normality and Mann-Whitney U test was applied for data analysis.

RESULTS

All twenty-two patients enrolled completed the study. The root surface analysis showed formation of 32.78% less number of resorption craters (P<0.05) and 39.49% less volume of resorption craters (P<0.05) in the test group premolars relative to the control group premolars.

CONCLUSIONS

The results of the present study, therefore, suggest that photobiomodulation reduces external root resorption during orthodontic tooth movement.

TRIAL REGISTRATION/REGISTRATION NUMBER

CTRI/2018/04/013520.

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.

Photobiomodulation increases intrusion tooth movement and modulates IL-6, IL-8 and IL-1β expression during orthodontically bone remodeling

This study investigated the effects of photobiomodulation (PBM) on upper molar intrusion movement, regarding acceleration of orthodontic movement and its molecular effects. The sample consisted of 30 patients with indication of tooth intrusion for oral rehabilitation. Teeth were divided into three different groups: G1 (n = 10) pre-molars without force or laser application (control); G2 (n = 10) upper molar intrusion; and G3 (n = 10) upper molar intrusion and PBM. On PBM treated molars, the teeth were irradiated with a low-power diode laser (808 nm, 100 mW), receiving 1 J per point, density of 25 J/cm² , with application of 10 s per point, 10 points (5 per vestibular and 5 per palatal region). Orthodontic force of intrusion applied every 30 days and PBM was performed immediately, 3 and 7 days after force application for 3 months. Gingival crevicular fluid was collected at the same time periods as the laser applications and interleukins (IL) 1-β, -6 and -8 were evaluated by enzyme-linked immunosorbent assay. Clinical measures were performed monthly to verify the amount of intrusion. The levels of IL-6, IL-8 and IL-1β increased under orthodontic force (G2 and G3) when compared to control group (G1), however, the cytokines levels were significantly higher after PBM (G3). The mean intrusion velocity was 0.26 mm/month in the irradiated group (G3), average duration of 8 months vs 0.17 mm/month for the non-irradiated group (G2), average duration of 12 months. This study suggests that PBM accelerates tooth movement during molar intrusion, due to modulation of IL-6, IL-8 and IL-1β during bone remodeling.