Short- and Medium-Term Effects of Low-Level Laser Therapy on Periodontal Status in Lingual Orthodontic Patients

The effects of low-level laser therapy and photodynamic therapy on oral health of fixed orthodontics patients. A systematic review and meta-analysis

Objective To investigate the effect of low-level laser and photodynamic therapy on the oral health, and periodontal tissue of fixed orthodontic patients and the effect of using photobiomodulation methods compared to routine plaque removal methods and the amount of plaque in fixed orthodontic patients. Method and materials First, the title and summary of related articles were collected by using the search strategy electronic databases PUBMED, EMBASE, Cochrane's CENTRAL, Scopus, ISI and all the articles that were published from the beginning to February 2023 were evaluated. The title, abstracts and full texts of all the relevant studies were reviewed respectively, and those meeting the criteria were entered into our study. Finally, the quality of the studies was examined and the results of the studies were pooled by means of random effects inverse variance meta-analysis. Results Eighteen randomized studies, conducted between 2015 and December 2022, were selected for meta-analysis. Five studies were conducted as split-mouth, twelve as parallel-group, and one as a cross-over design. Among the studies, five examined the effects of low-level laser therapy and twelve assessed the effects of photodynamic therapy. The meta-analysis revealed that photodynamic therapy significantly reduced probing depth compared to scaling (MD=-0.2 mm, P<0.001), though the difference does not seem to be clinically significant. But no significant differences between photodynamic therapy and scaling or low-level laser therapy and control groups in terms of plaque index, or bleeding on probing, gingival crevicular fluid volume, gingival recession, clinical attachment loss, bacterial load and concentrations of inflammatory substances across multiple follow-up periods. Conclusion Moderate evidence indicates that photodynamic therapy (PDT) is comparable to conventional methods in improving oral health, as measured by periodontal indices, inflammatory proteins, bacterial colonies, and white spot lesions, making it a suitable alternative. Limited evidence suggests low-level laser therapy (LLLT) may improve oral health, particularly addressing caries, but further research is needed.

Non-surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic treatment

BACKGROUND

Deviation from a normal bite can be defined as malocclusion. Orthodontic treatment takes 20 months on average to correct malocclusion. Accelerating the rate of tooth movement may help to reduce the duration of orthodontic treatment and associated unwanted effects including orthodontically induced inflammatory root resorption (OIIRR), demineralisation and reduced patient motivation and compliance. Several non-surgical adjuncts have been advocated with the aim of accelerating the rate of orthodontic tooth movement (OTM).         OBJECTIVES: To assess the effect of non-surgical adjunctive interventions on the rate of orthodontic tooth movement and the overall duration of treatment.

SEARCH METHODS

An information specialist searched five bibliographic databases up to 6 September 2022 and used additional search methods to identify published, unpublished and ongoing studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of people receiving orthodontic treatment using fixed or removable appliances along with non-surgical adjunctive interventions to accelerate tooth movement. We excluded split-mouth studies and studies that involved people who were treated with orthognathic surgery, or who had cleft lip or palate, or other craniofacial syndromes or deformities.

DATA COLLECTION AND ANALYSIS

Two review authors were responsible for study selection, risk of bias assessment and data extraction; they carried out these tasks independently. Disagreements were resolved by discussion amongst the review team to reach consensus.  MAIN RESULTS: We included 23 studies, none of which were rated as low risk of bias overall. We categorised the included studies as testing light vibrational forces or photobiomodulation, the latter including low level laser therapy and light emitting diode. The studies assessed non-surgical interventions added to fixed or removable orthodontic appliances compared to treatment without the adjunct. A total of 1027 participants (children and adults) were recruited with loss to follow-up ranging from 0% to 27% of the original samples.  Certainty of the evidence For all comparisons and outcomes presented below, the certainty of the evidence is low to very low. Light vibrational forces  Eleven studies assessed how applying light vibrational forces (LVF) affected orthodontic tooth movement (OTM). There was no evidence of a difference between the intervention and control groups for duration of orthodontic treatment (MD -0.61 months, 95% confidence interval (CI) -2.44 to 1.22; 2 studies, 77 participants); total number of orthodontic appliance adjustment visits (MD -0.32 visits, 95% CI -1.69 to 1.05; 2 studies, 77 participants); orthodontic tooth movement during the early alignment stage (reduction of lower incisor irregularity (LII)) at 4-6 weeks (MD 0.12 mm, 95% CI -1.77 to 2.01; 3 studies, 144 participants), or 10-16 weeks (MD -0.18 mm, 95% CI -1.20 to 0.83; 4 studies, 175 participants); rate of canine distalisation (MD -0.01 mm/month, 95% CI -0.20 to 0.18; 2 studies, 40 participants); or rate of OTM during en masse space closure (MD 0.10 mm per month, 95% CI -0.08 to 0.29; 2 studies, 81 participants). No evidence of a difference was found between LVF and control groups in rate of OTM when using removable orthodontic aligners. Nor did the studies show evidence of a difference between groups for our secondary outcomes, including patient perception of pain, patient-reported need for analgesics at different stages of treatment and harms or side effects.  Photobiomodulation Ten studies assessed the effect of applying low level laser therapy (LLLT) on rate of OTM. We found that participants in the LLLT group had a statistically significantly shorter length of time for the teeth to align in the early stages of treatment (MD -50 days, 95% CI -58 to -42; 2 studies, 62 participants) and required fewer appointments (-2.3, 95% CI -2.5 to -2.0; 2 studies, 125 participants). There was no evidence of a difference between the LLLT and control groups in OTM when assessed as percentage reduction in LII in the first month of alignment (1.63%, 95% CI -2.60 to 5.86; 2 studies, 56 participants) or in the second month (percentage reduction MD 3.75%, 95% CI -1.74 to 9.24; 2 studies, 56 participants). However, LLLT resulted in an increase in OTM during the space closure stage in the maxillary arch (MD 0.18 mm/month, 95% CI 0.05 to 0.33; 1 study; 65 participants; very low level of certainty) and the mandibular arch (right side MD 0.16 mm/month, 95% CI 0.12 to 0.19; 1 study; 65 participants). In addition, LLLT resulted in an increased  rate of OTM during maxillary canine retraction (MD 0.01 mm/month, 95% CI 0 to 0.02; 1 study, 37 participants). These  findings were not clinically significant. The studies showed no evidence of a difference between groups for our secondary outcomes, including OIIRR, periodontal health and patient perception of pain at early stages of treatment. Two studies assessed the influence of applying light-emitting diode (LED) on OTM. Participants in the LED group required a significantly shorter time to align the mandibular arch compared to the control group (MD -24.50 days, 95% CI -42.45 to -6.55, 1 study, 34 participants). There is no evidence that LED application increased the rate of OTM during maxillary canine retraction (MD 0.01 mm/month, 95% CI 0 to 0.02; P = 0.28; 1 study, 39 participants ). In terms of secondary outcomes, one study assessed patient perception of pain and found no evidence of a difference between groups.   AUTHORS' CONCLUSIONS: The evidence from randomised controlled trials concerning the effectiveness of non-surgical interventions to accelerate orthodontic treatment is of low to very low certainty. It suggests that there is no additional benefit of light vibrational forces or photobiomodulation for reducing the duration of orthodontic treatment. Although there may be a limited benefit from photobiomodulation application for accelerating discrete treatment phases, these results have to be interpreted with caution due to their questionable clinical significance. Further well-designed, rigorous RCTs with longer follow-up periods spanning from start to completion of orthodontic treatment are required to determine whether non-surgical interventions may reduce the duration of orthodontic treatment by a clinically significant amount, with minimal adverse effects.

Effects of Laser Therapy on Periodontal Status in Adult Patients Undergoing Orthodontic Treatment

Orthodontic treatment with fixed devices should only be indicated in case of a stable, non-active periodontal disease status. Throughout orthodontic treatment, a careful assessment of the periodontal status is advised. Due to its anti-inflammatory and antimicrobial effects, laser therapy is frequently used as an adjunct to classic periodontal therapy. The aim of this study was to evaluate the advantages and limitations of the use of laser therapy on periodontal status during orthodontic treatment. Throughout the 9 months during which this placebo-controlled, single-blind clinical trial was conducted, 32 patients were included in the study, divided into two groups: microscope “+” (patients who observed the bacteria within the dental plaque-sample examination on the screen of a dark-field microscope in real time) and microscope “−” (patients who did not see the oral pathogens using a dark-field microscope). For all patients, using the split-mouth study design, laser therapy was applied to one hemiarch (HL), whereas the other hemiarch received treatment without active light (HC). After one month, by analyzing the main indicators of periodontal health status, we found that the plaque index (PI) and bleeding on probing (BOP) values were significantly decreased after receiving treatment (for PI: HL-p = 0.0005, HC-p = 0.0297; for BOP: HL-p = 0.0121, HC-p = 0.0236), whereas the probing-depth (PD) values remained almost the same as before treatment (HL-p = 1.5143; HC-p = 1.4762). Conclusions: The use of the dark-field microscope proved to be beneficial in sensitizing patients to the presence of bacteria in the oral cavity and motivated them to strictly follow the rules of oral hygiene. Laser treatment can be a valuable aid in periodontal therapy, but only in adjunction with mechanical therapy.

Photobiomodulation impacts the levels of inflammatory mediators during orthodontic tooth movement? A systematic review with meta-analysis

During orthodontic tooth movement (OTM), there is the release of cytokines in the gingival crevicular fluid (GCF) that are supposed to participate in the bone remodeling. This systematic review aimed at assessing the effects of photobiomodulation (PBM) on the levels of these cytokines during OTM. This systematic review according to Cochrane Collaboration guidelines aimed to answer the clinical question following the PICOS strategy. The broad search in the literature was performed before 05 April, 2021 in six electronic databases (Pubmed, Web of Science, Scopus, Embase, Cochrane, Biblioteca Virtual de Saúde) and supplemented by the grey literature. The risk of bias of randomized and non-randomized clinical trials was evaluated by two tools: RoB 2 and ROBINS-I. Mean and standard deviation of cytokine levels was extracted to meta-analysis, and the GRADE system was applied to assess the quality of the evidence. Nine studies were included in this review. Low-level laser therapy (LLLT) was the photobiomodulation type used in most of the studies (n = 8). The wavelengths used varied from 618 to 980 nm and also differed concerning the light emission pattern. LLLT increased the levels of IL-1β, IL-8, OPN, and PGE2, but not TNF-α1, TGF-β1. The levels of IL6, RANKL, and OPG presented conflicting results. LLLT was statistically associated with an increase of IL-1β levels (standard mean difference [SMD] = 1.99; 95% confidence interval = 0.66 to 3.33; p < 0.001) with low certainty of evidence. LLLT may increase the levels of IL-1β and other cytokines; however, the results should be interpreted with caution due to protocol variations between studies, and the few studies added in the meta-analysis.

Effects of Photobiomodulation on the Upper First Molar Intrusion Movement Using Mini-Screws Anchorage: A Randomized Controlled Trial

Objective: The aim of this study was to quantify the changes obtained when the molar intrusion movement is complemented by photobiomodulation (PBM). Background: A common problem in adult patients is the super-eruption of maxillary molars caused by the loss of the antagonist tooth. Super-erupted molars impair oral rehabilitation and can cause both occlusal and functional problems. There is increasing research confirming the benefits of adjunctive PBM during orthodontic treatment. Methods: Twenty patients with indication of a maxillary first molar intrusion for oral rehabilitation were selected. Patients were randomized into two groups to receive orthodontic intrusion (control group) or the same treatment complemented by PBM (PBM group) in repeated doses (days 0, 1, 2, 3, 4, and 7 from the start of the intrusion and in each monthly follow-up) by using a low-power red laser diode (670 nm, 150 mW, 12 min around the molar). Plaque index (PI), probing depth (PD), and bleeding of probing (BOP) were assessed at 0, 1, 2, 3, and 6 months. Stereolithography models generated from an intraoral scanner were taken at 0, 3, and 6 months and cone beam computed tomography (CBCT) records were taken at 0 and 6 months. Mean intrusion distance, mean intrusion velocity, and volumetric resorption were calculated. Results: Periodontal clinical assessments (PI, PD, and BOP) and mean intrusion distance or mean intrusion velocity yielded no differences (p > 0.05) between groups. However, PBM group showed lower values of all these scores during the first 3 months. Intraoral scanner and CBCT were equally effective in accurately monitoring the intrusion distance (p > 0.05). CBCT records allowed volumetric evaluation of the root resorption process, being lesser in the PBM group, but not significantly (p > 0.05). Conclusions: During orthodontic intrusion process, the adjunctive application of PBM may provide better periodontal records and lower progression of root resorption at the expense of a little lower intrusion distance and velocity.

Effects of Low Level Laser Therapy (LLLT) on Serum Values of Interleukin 6 (IL-6) in Patients with Periodontitis and Type 2 Diabetes Mellitus (T2DM)

BACKGROUND

In patients with T2DM, the therapeutic effects of conservative treatment are quite limited, and there is a need for additional therapeutic procedures to achieve the desired satisfactory and solid effect. Low-level laser therapy (LLLT) has an anti-inflammatory effect, and is used to heal lesions. This mechanism is realized through inhibition of lipopolysaccharides (LPS), so it can be used in the treatment of periodontal disease in patients with diabetes.

OBJECTIVE

The aim of this study is to assess the effect of level laser therapy (LLLT) on serum IL-6 values in patients with periodontitis and T2DM.

METHODS

Patients at age between 35-60 years old, with chronic periodontitis (CH) where the clinical loss of attachment (CAL) was ≥4 mm therefore covering at least 50 % of affected teeth. In this study we included 80 patients, divided into two groups: 40 patients with type 2 diabetes mellitus (2TDM) treated with conservative periodontal treatment supplemented with laser therapy (LLLT), group A, and 40 patients with 2TDM, conservatively treated without LLLT. therapy i.e. group B. The laser light was applied to the gingiva in separate quadrants in 5 sessions for the next five days in a row. Blood samples were taken from all subjects at the first treatment, then in 6 weeks and 3 months after treatment, and interleukin 6 (IL-6) levels were measured. The blood samples in the test tubes remained for about 30 minutes and were then distributed in a biochemical laboratory, where they were centrifuged at 6,000 rpm for 10 minutes. The serum was separated from the test tube and transferred to the eppendorph. All serum samples were stored at -80 ° C until complete analysis and determination of IL-6, according to the standardized methodology.

RESULTS

In group A, on the first examination serum IL-6 levels varies in the interval 11.54 ± 1.11 pg / mL, after 6 weeks of therapy the values range between 11.26 ± 0.77 pg / mL, and after 3 months of therapy levels oscillate at intervals of 11.02 ± 0.67 pg / mL. In group B the findings are similar. At the first examination, the serum IL-6 values were 11.56 ± 0.81 pg / mL, after 6 weeks of therapy ranged from 11.59 ± 0.71 pg / mL, and after 3 months of therapy levels were recorded at intervals. 11.41 ± 0.78 pg /mL. The serum IL-6 value after 6 weeks of therapy in patients in group B for Z = -2.04 and p <0.05 (p = 0.04) was significantly higher than in patients in group A, while after 3 months of therapy in patients in group B for Z = -2.42 and p <0.05 (p = 0.02) is significantly higher than the value in patients in group A.

CONCLUSION

LLLT resulted in significantly reduced serum IL-6 values in patients with periodontitis and T2DM after 6 weeks and 3 months of therapy in which conservative treatment was supplemented with LLLT.

Low-level laser-aided orthodontic treatment of periodontally compromised patients: a randomised controlled trial

Low-level laser irradiation (LLLI) shows effects in orthodontic pain relief and periodontal inflammation control. The aim of this article is to investigate the analgesic and inflammation-modulatory effects of low-level laser irradiation among orthodontic patients with compromised periodontium. A randomised controlled trial with split-mouth design was conducted in 27 adults with treated and controlled chronic periodontitis over 6 months. One side of the dental arch underwent repeated treatment under a 940-nm diode laser (EZlase; Biolase Technology Inc.) with a beam size of 2.8 cm² for 60 seconds at 8.6 J/cm², whilst the other side received pseudo-laser treatment. Laser irradiation was applied repeatedly for 8 times during the first 6 weeks after bracket bonding and monthly thereafter until the end of orthodontic treatment. Subjective pain (assessed by visual analogue scale in pain diary and by chairside archwire activation), periodontal status (assessed by periodontal clinical parameters), cytokines in gingival crevicular fluid (interleukin 1β, prostaglandin E₂, substance P) and periodontopathic bacteria (Porphyromonas gingivalis and Treponema denticola) in supragingival plaque were assessed. The intensity of pain was lower on the laser-irradiated side at multiple follow-up visits (P < 0.05). The pain subsided 1 day earlier on the laser side, with a lower peak value during the first week after initial archwire placement (P < 0.05). The laser side exhibited a smaller reduction in bite force during the first month (mean difference = 3.17, 95% CI: 2.36-3.98, P < 0.05 at 1-week interval; mean difference = 3.09, 95% CI: 1.87-4.32, P < 0.05 at 1-month interval). A smaller increase was observed in the plaque index scores on the laser side at 1-month (mean difference = 0.19, 95% CI: 0.13-0.24, P < 0.05) and in the gingival index scores at the 3-month follow-up visit (mean difference = 0.18, 95% CI: 0.14-0.21, P < 0.05). Laser irradiation inhibited the elevation of interleukin-1β, prostaglandin E₂ and substance P levels during the first month (P < 0.05). However, no intergroup difference was detected in the bacteria levels. Low-level laser irradiation exhibits benefits in pain relief and inflammation control during the early stage of adjunctive orthodontic treatment in periodontally compromised individuals.

Analysis of Human Tooth Pulp Chamber Temperature After 670 nm Laser Irradiation: In Vitro Study

OBJECTIVE

One of the limiting factors of employing laser radiation on dental therapies is the potential of causing thermal injuries to pulp tissues. The purpose of this study was to evaluate intra-chamber temperature increase on extracted human teeth exposed to 670 nm wavelength InGaAlP laser diode radiation.

MATERIALS AND METHODS

In vitro intra-chamber temperature measurements of 12 standardized human teeth (incisors, canines, premolars, and molars; n = 3) were taken both before and after laser radiation. A type-K thermocouple fast-response thermocouple wire with a 0.5 mm diameter probe was inserted into the tooth pulp chamber (ICEL-Manaus-brand). The laser device Lasotronic-brand InGaAlP laser diode was used to irradiate tooth enamel, perpendicularly to the external surface for 30 sec, with power of levels of 340, 272, 204, 136, and 68 mW. The measurements were taken at three time points: 0, 30 sec, and 3 min after the laser irradiation. Measurements were repeated 24 h after removal and reinsertion of the probe in the pulp chamber. The temperature gradient (ΔT in °C) was calculated (ΔT = final temperature-initial temperature) for each group. Data of ΔT were statistically analyzed by two-way analysis of variance (ANOVA) at the 95% confidence level and compared by Tukey post hoc test (α = 0.05).

RESULTS

ANOVA showed statistically significant differences to the interaction of factors (p < 0.05). The highest ΔT values obtained were observed to incisors with 340 mW, 272 mW; 204 mW of power (respectively 4.7°C, 4.2°C, and 3.1°C); and canines presented the lowest ΔT (0.8°C-0.3°C) with no influence of power output.

CONCLUSIONS

Since the thermal increase was observed in this study, especially in incisors, attention should be paid to avoid pulpal damage.