Effects of low-level light therapy on xerostomia related to hyposalivation: a systematic review and meta-analysis of clinical trials

Shedding light on Brazil's contribution to photobiomodulation research in oral medicine: a bibliometric study

The aim of this study was to verify the role of Brazilian researchers in publications related to photobiomodulation (PBM) in the field of oral medicine. We examined ten years from 2012 to 2022 across 16 journals. Our analysis included scientific publications with a Brazilian author either in the first or last position and publications from international collaborations. The search yielded 43,525 publications. After examining titles and abstracts, 269 studies were categorized as having a specific emphasis on PBM in oral medicine, of which 147 (54.6%) were undertaken by research groups based in Brazil. The citations ranged from 1 to 149 (an average of 31 per manuscript). The male-to-female ratio of first and last author was 1:2 and 1:1.4, respectively. Brazilian involvement in the field of PBM was significant, with a marked focus on basic research, clinical applications, and technological advances. Our results also underscore the remarkable participation of female researchers in pivotal roles. Brazilian publications positively impacted healthcare worldwide using PBM in oral medicine, as evidenced by the substantial number of articles published and the citations of these articles received.

Effect of led photobiomodulation on tooth movement, gingival hypertrophy and pain in response to treatment with fixed orthodontic appliance

Photobiomodulation (PBM) is a form of treatment that uses low-power red and near-infrared light to stimulate tissue repair and regeneration at the cellular level. 32 subjects (198 teeth examined), 10 males and 22 females aged 14.6 ± 2.0 years, with mild dental crowding were included in a randomised, controlled clinical trial. The patients were treated with a fixed orthodontic appliance (FOA). Subjects were randomised into an experimental group (a PBM group irradiated with an LED light source with wavelengths of 625 nm, 660 nm and 850 nm simultaneously and an irradiance of 16 mW/cm²) and a placebo control group that received non-therapeutic irradiation with visible light. PBM therapy began within the first 2 days of appliance insertion and was administered twice weekly for 4 weeks. The rate of tooth movement (a change in distance at the same selected point on the occlusal plane of the tooth determined by measurements on 3D models), the presence of gingival hypertrophy (with a free gingival margin of at least 1 mm occlusal to the enamel-cement junction), the plaque index (PI), the sulcus bleeding index (SBI) and the subjective pain sensation using the visual analogue scale (VAS) were monitored. In the experimental PBM group (N = 14), the rate of movement with the FOA was statistically significantly higher at both 1 week of placement (0.5 mm [95%CI: 0.4-0.8]) and 4 weeks (1.1 mm [95%CI: 0.8-1.4]) than in the placebo group (N = 18), where the values were (0.4 mm [95%CI: 0.2-0.5]) at 1 week and (0.6 mm [95%CI: 0.4-0.9]) at 4 weeks. A lower incidence of gingival hypertrophy was observed in the PBM group (21.4%) than in the placebo group (55.6%) after 4 weeks (Mann-Whitney U-test, p < 0.05). PBM with LED accelerated orthodontic tooth movement during the levelling and alignment phase and reduced the incidence of gingival hypertrophy.

Management of radiotherapy-induced hyposalivation using photobiomodulation therapy: a case series

It is not uncommon for individuals receiving radiotherapy for head and cancers to experience dry mouth sensation (xerostomia), salivary hypofunction (hyposalivation) and taste changes. The present study aimed to evaluate the short-term effectiveness of biweekly photobiomodulation therapy (PBMT) in managing these radiotherapy-induced adverse effects and its impact on oral health-related quality of life. Ten patients who developed xerostomia and hyposalivation secondary to radiotherapy for head and neck cancer were included. The study assessments included clinician-based [the stimulated (SSF) and unstimulated salivary flow (USSF) and taste change questionnaire] and patient-based measures [Shortened Xerostomia Inventory (SXI) and Oral Health Impact Profile (OHIP-5)]. The 10 participants (males = 5, females = 5) had a mean age of 52 (± 15) years. Half were diagnosed with nasopharyngeal squamous cell carcinoma. From visits 1 to 8, 80% showed increased USSF and/or SSF, but these were limited and not significant (p > 0.05). Nevertheless, 80% of the patients had lower xerostomia scores, 60% had less dryness frequency, and 40% showed taste improvement. Improvement in oral health-related quality of life was only observed in 30% of the participants. Strong proportional correlations were found between USSF and SSF as well as SXI and OHIP-5 at study visits 1 and 8 (p < 0.05). The findings showed the usefulness of PBMT in reducing xerostomia and taste changes and possibly increasing salivary flow over a 4-week duration. However, randomised clinical trials are needed to assess the long-term effectiveness of PBMT compared to other management options.Clinical study registration: The study was prospectively registered with the US National Library of Medicine's clinical trial registry on 13 September 2022 [ClinicalTrials.gov ref: NCT05538169].

The Oral Microbial Ecosystem in Age-Related Xerostomia: A Critical Review

Xerostomia is a widespread condition among the elderly, impacting as many as 50% of individuals within this demographic. This review aims to analyze the association between age-related xerostomia and the oral microbial ecosystem. Xerostomia not only induces discomfort but also heightens the susceptibility to oral diseases, including dental caries and infections. The oral microbial ecosystem, characterized by a dynamic equilibrium of microorganisms, is integral to the maintenance of oral health. Dysbiosis, defined as a microbial imbalance, can further aggravate oral health complications in those suffering from xerostomia. This review investigates the composition, diversity, and functionality of the oral microbiota in elderly individuals experiencing xerostomia, emphasizing the mechanisms underlying dysbiosis and its ramifications for both oral and systemic health. A comprehensive understanding of these interactions is vital for the formulation of effective management and prevention strategies aimed at enhancing the quality of life for older adults.

Investigating the safety of photobiomodulation in oral carcinogenesis: insights into cell proliferation, invasion, and apoptosis via the 4NQO model

The present investigation aimed to assess the safety of photobiomodulation (PBM) on the oral carcinogenesis process induced by 4NQO, focusing on cell proliferation and apoptosis. Sixty-six Wistar rats received systemic 4NQO for 12 (n = 33) and 20 weeks (n = 33), divided into Control group, PBM 0.3 J, and PBM 1 J. Applications for PBM occurred three times a week. At weeks 12 and 20, the animals were euthanized. The immunoreactivity for anti-ROS1 and anti-p53 antibodies was also assessed. Statistical analysis was assessed by multiple t-tests, Kruskal-Wallis, and Spearman's correlation. At 12 weeks, PBM 1 J group had nodular lesions, distinct from control and PBM 0.3 J groups (p = 0.005). At 20 weeks, nodular lesions were common in control and PBM 0.3 J groups. Histopathological characteristics did not significantly differ between groups at 12 (p = 0.30) and 20 weeks (p = 0.58). Epithelial dysplasia (n = 21) was common at 12 weeks. After 20 weeks, most of the cases revealed squamous cell carcinoma (n = 24). No differences were observed in the immunostaining of p53 and ROS1 among the control and experimental groups and there was no correlation of these proteins with clinicopathological data. During the carcinogenesis process, the PBM did not modify the development of oral lesions and the expression of proliferative and apoptosis proteins.

The supportive use of photobiomodulation on salivary glands: a narrative review and meta-analysis

PURPOSE

Radiotherapy is one of the main strategies used in the treatment of cancer patients and it can cause early or late xerostomia and/or hyposalivation. Therapeutic management of xerostomia includes oral hygiene, sialogenic agents among others.

METHODS

This study reviews the use of extra-oral salivary glands photobiomodulation in treating xerostomia and/or hyposalivation after radiotherapy and performs a meta-analysis of this data.

RESULTS

After a broad search of the literature, eight clinical studies were selected.

DISCUSSION

In a safe way, the studies found that extra-oral stimulation of the salivary glands has benefits in the hyposalivation and changes in salivary flow resulting from lesions by radiotherapy. A meta-analysis found significant values in pain comparing the pre- and post-treatment moments (MD - 3.02, I2 95%, IC - 5.56; - 0.48) and for stimulated salivary flow at 30 days after the end of radiotherapy (MD 2.90, I2 95%, IC 1.96; 3.84).

CONCLUSION

The most promising parameters comprise wavelengths between 630 and 830 nm, radiant exposure from 2 to 10 J/cm2, two-to-three times a week, before the radiotherapy damage, and homogeneously in the glands. Therefore, Light-Emitting Diode (LED) stimulation of larger areas than the punctual stimulation of small millimeters of the Low-Level Laser Therapy (LLLT) appears to be promising.

Immediate effects of photobiomodulation on saliva production

PURPOSE

To verify the immediate effects of photobiomodulation on the production of salivary flow and the correlation of demographic, anthropometric and medication use data.

METHODS

The study included 100 healthy individuals, aged between 18 and 76 years (mean 27.2 years), randomly split into an experimental group and a placebo group. Assessments of anthropometric measurements, self-perception of saliva production and sialometry were performed. Next, LASER irradiation was carried out at an infrared wavelength (808 nanometers) with 100 milliwatts (mw) of power at five intraoral points: on the sublingual glands and bilaterally on the submandibular and parotid glands, at doses of 9, 18 and 24 joules (J). Sialometry was repeated after each application. The control group received the same procedures with placebo equipment.

RESULTS

There was a statistical association in the self-perception of reduced saliva in the experimental group for the 24J dose and in sialometry and in the reduction in salivary flow for the 18J and 24J doses and an increase to 9J, in both groups. There was no association when comparing the experimental and placebo groups. Multiple multinomial regression analysis revealed that the reduction or increase in salivary flow is independent of demographic, anthropometric and medication use variables.

CONCLUSION

The bioinhibitory action of photobiomodulation on healthy salivary glands occurred at a dose of 18J and 24J, while the biostimulant action happened at a dose of 9J, regardless of demographic, anthropometric variables and medication use. The self-perception of reduced salivary flow occurred at 24J.

Effect of photobiomodulation therapy on pain perception during anesthetic puncture of dental local anesthesia: A systematic review

BACKGROUND

Local anesthetic puncture is often related to the experience of pain. This study aimed to systematically analyze the literature on changes in pain perception during the anesthetic puncture of dental local anesthesia after Photobiomodulation Therapy (PBMT).

MATERIAL AND METHODS

An electronic search was performed in eight primary databases (Embase, LILACS, BBO, LIVIVO, MedLine via PubMed, SciELO, Scopus, and Web of Science) and three additional ones (EASY, Google Scholar, and OATD) to partially capture the "gray literature". The PICO strategy was used to identify randomized clinical trials evaluating the analgesic effect of PBMT in the anesthetic puncture site of dental local anesthesia compared to placebo or control groups, without restrictions on publication language and year. Two reviewers extracted the data and assessed the individual risk of bias of the eligible studies using the Cochrane Collaboration Risk of Bias Tool version 2.0.

RESULTS

The electronic search found 3,485 records, of which eight met the eligibility criteria and were included in the qualitative synthesis. The studies were published from 2011 to 2022. None of the included studies had a low risk of bias. PBMT groups showed no significant difference in pain scores compared to placebo and control groups of most studies.

CONCLUSION

Based on a low to very low certainty of evidence, PBMT seems to have no effect on pain perception during anesthetic puncture in patients undergoing dental local anesthesia.

The effect of physical interventions on pain control after orthodontic treatment: A systematic review and network meta-analysis

OBJECTIVE

Pain is a frequent adverse reaction during orthodontic treatment, which can significantly reduce treatment compliance and compromise the expected treatment effect. Physical interventions have been used to alleviate pain after orthodontic treatment, but their effectiveness is controversial. This study used a network meta-analysis to assess the efficacy of various physical interventions typically used in managing pain after orthodontic treatment, with a view to provide evidence-based recommendations for representative interventions for orthodontic pain relief during peak pain intensity.

METHODS

A systematic search of six electronic databases, from their respective inception dates, was conducted to identify relevant literature on the efficacy of various typical physical interventions for managing pain after orthodontic treatment. Literature screening was performed according to the Cochrane System Evaluator's Manual. Stata 16.0 was used to assess heterogeneity, inconsistency, publication bias, and sensitivity to generate an evidence network diagram and conduct a network meta-analysis.

RESULTS

In total, 771 articles were reviewed to collect literature on interventions, including low-level laser therapy (LLLT), vibration, acupuncture, and chewing. Of these, 28 studies using a visual analog scale (VAS) as an outcome indicator were included. The results showed that LLLT, vibration, acupuncture, and chewing effectively relieved the pain symptoms in patients after orthodontic treatment. At 24 h post-treatment, LLLT (surface under the cumulative ranking curve [SUCRA] = 80.8) and vibration (SUCRA = 71.1) were the most effective interventions. After 48 h of treatment, acupuncture (SUCRA = 89.6) showed a definite advantage as the best intervention.

CONCLUSION

LLLT, vibration, acupuncture, and chewing can alleviate pain associated with orthodontic treatment. Among these interventions, acupuncture was found to be the most effective at 48 h after orthodontic treatment. In addition, acupuncture demonstrated long-lasting and stable pain-relieving effects. However, further studies are needed to determine the most suitable equipment-specific parameters for acupuncture in relieving pain associated with orthodontic treatment.

Efficacy of photobiomodulation therapy combined with mobile health education in patients with head and neck cancer suffering from chronic xerostomia after radiotherapy: protocol for a three-arm, randomised, placebo-controlled, double-blinded study

INTRODUCTION

The role of photobiomodulation (PBM) therapy for oral tissue damage induced by cancer treatment is currently unclear, and there is low-quality to moderate-quality evidence supporting the use of this approach for treating xerostomia and/or hyposalivation. Consequently, patients with head and neck cancer increasingly turn to basic oral hygiene to alleviate salivary gland dysfunction, and their adherence can be improved by mobile health (mHealth) education. The primary objective of this study will be to analyse the effects of different doses of PBM therapy (7.5 J/cm2 vs 3 J/cm2) plus mHealth education on quality of life (QoL), oral health, salivary secretion and salivary gland ultrasound assessment at postintervention and at the 6-month follow-up in patients with head and neck cancer after radiotherapy compared with those in control group.

METHODS AND ANALYSIS

A prospective, three-arm, randomised, placebo-controlled, double-blinded study will be conducted among patients with head and neck cancer suffering from chronic xerostomia. A total of 20 patients per arm will be included and randomly assigned to receive 7.5 J/cm2 of PBM, 3 J/cm2 of PBM or placebo therapy. PBM therapy will be applied during 24 sessions at 22 points extra and intraorally two times per week for 3 months, combined with a mobile application (https://www.laxer.es). The assessments will be recorded at the beginning of the study, at postintervention and at the 6-month follow-up. The primary outcomes will be QoL, oral health, salivary secretion and salivary gland ultrasound. The pain pressure threshold, functional performance, mood and sleep quality will be secondary indicators.

ETHICS AND DISSEMINATION

This study received ethics approval from the Andalusian Biomedical Research Ethics Portal (2402-N-21 CEIM/CEI Provincial de Granada) according to the Declaration of Helsinki for Biomedical Research. The results of this study will be presented at national and international conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT05106608.

Regeneration of taste through sonic hedgehog upregulation by photobiomodulation

This study investigated photobiomodulation (PBM) effects in Sonic hedgehog (Shh) signaling as a potential approach to taste preservation and regeneration. Primary taste cell (TC) cultures were treated with Shh antagonist vismodegib and irradiated using a continuous wave type 630 nm light-emitting diode (10 mW/cm2 ) array, with single or multiple doses of 30 J/cm2 to determine dose inducing significant upregulation effect. Shh, Ptch, Smo, and Gli1 were significantly upregulated at 120 J/cm2 , used as the minimum dose in vivo. Vismodegib was administered via daily oral gavage for 21 days (30 mg/kg) to induce Shh inhibition in the tongue of rat animal models resulting in taste bud damage and taste dysfunction. PBM treatment using a 630 nm laser (3 W/cm2 ) at a radiant exposure of 120 J/cm2 (24 J/cm2  × 5) successfully upregulated the Shh protein expression, regenerated taste buds, and recovered taste function.

A scoping review on hyposalivation associated with systemic conditions: the role of physical stimulation in the treatment approaches

BACKGROUND

Several systemic conditions can result in distinct degrees of salivary gland damage and consequent hypofunction. The development of successful management schemes is highly challenging due to the complexity of saliva. This study aimed to systematically map the literature on the physical stimulation of salivary glands for hyposalivation management and the response of individuals according to different systemic conditions causing salivary impairment.

METHODS

A systematic search in the literature was performed. Two reviewers independently selected clinical trials, randomized or not, that used physical stimulation to treat hyposalivation caused by systemic conditions. Studies evaluating healthy subjects without hyposalivation were included as controls. Single-arm clinical studies or case series were also included for protocol mapping (PRISMA extension for scoping reviews).

RESULTS

Out of 24 included studies, 10 evaluated healthy subjects, from which 9 tested transcutaneous electrical nerve stimulation (TENS) and 1 tested acupuncture and electroacupuncture. Fourteen studies evaluated individuals with hyposalivation: 6 applied TENS, 6 applied low-level laser therapy (LLLT), and 2 applied acupuncture, carried out in post-chemotherapy, medication use, postmenopausal women, hemodialysis patients, smokers, diabetics, Sjögren's syndrome (SS). All showed increased salivation after treatment, except for two LLLT studies in individuals with SS.

CONCLUSIONS

Among the different patient groups, individuals with Sjögren's syndrome (SS) exhibited the poorest responses, while those with medication-induced hyposalivation demonstrated the most favorable treatment outcomes, independently of the management strategy for saliva stimulation. It means that physical stimulation of salivary glands holds promise as an alternative for managing hyposalivation in cases of reversible gland damage. However, to make informed decisions in current practice, it is necessary to conduct new well-designed randomized clinical trials with appropriate methodologies.

Photobiomodulation for the management of xerostomia and oral mucositis in patients with cancer: a randomized clinical trial

To evaluate the applicability of photobiomodulation therapy (PBM-T) in the management of xerostomia and OM. Fifty-three patients with head and neck squamous cell carcinoma were randomized into two groups: Sham and PBM-T. The Sham group received artificial saliva and laser simulation, while the PBM-T group received artificial saliva and PBM-T. Xerostomia-related quality of life (QoL), the presence or absence of OM lesions, the decayed-missing-filled teeth (DMFT) index, and periodontal charts were evaluated. The results of the QoL questionnaire, DMFT index, and periodontal chart were analyzed with the Kruskal-Wallis test, followed by the Student-Newman-Keuls test, while OM findings were compared using the Mann-Whitney test. QoL scores significantly increased in the Sham group (p < 0.0001), denoting more severe xerostomia symptoms (p = 0.0074), and decreased in the PBM-T group, indicating no or very mild xerostomia. Higher grades of OM were found in the Sham group than the PBM-T group (p = 0.0001). There was no significant difference in DMFT index or periodontal charts between the groups (p > 0.05). PBM-T improved QoL in patients with head and neck cancer treated with radiotherapy, whether as radiation alone or as an adjunct to chemotherapy and surgery.

Efficacy of Photobiomodulation in Reducing Symptomatology and Improving the Quality of Life in Patients with Xerostomia and Hyposalivation: A Randomized Controlled Trial

Objectives: To evaluate the efficacy of photobiomodulation (PBM) treatment in patients with xerostomia and hyposalivation and assess their quality of life over a one year of follow-up. Material and methods: A single-blind randomized controlled trial. A total of 60 patients with xerostomia were included (30 PBM cases and 30 placebo controls). Photobiomodulation was performed with a diode laser (810 nm, 6 J/cm2), while the controls underwent simulated treatment. One weekly session was carried out for a total of 6 weeks (total six sessions). The study parameters were recorded at baseline, after three and six weeks, and at one year post-treatment. Xerostomia was assessed using a salivary flow visual analog scale (VAS) and the Xerostomia Inventory (XI). The Hospital Anxiety and Depression (HAD) scale, Oral Health Impact Profile (OHIP-14), Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) were also administered. Results: The patients subjected to PBM therapy showed a significant improvement of xerostomia based on the drainage test, and of oral quality of life (p < 0.001). The depression score of the HAD (HAD-D) and the ESS showed improvement, though without reaching statistical significance (p > 0.05). The placebo group showed significant changes in the xerostomia VAS score at 6 weeks (p = 0.009), with no variations in any of the other studied parameters (p > 0.05). The beneficial effects of the diode laser in the PBM group persisted at one year post-treatment. Conclusions: Photobiomodulation with the diode laser is effective in patients with xerostomia and hyposalivation, and thus should be taken into account as a treatment option.