Low intensity laser for reducing pain from anesthetic palatal injection

Comparative evaluation of the effectiveness of transcutaneous electric nerve stimulation and photobiostimulation using diode laser prior to local anesthesia administration in children undergoing bilateral orthodontic extraction- a randomized controlled clinical trial

This study aimed to evaluate and compare the effectiveness of transcutaneous electric nerve stimulation (TENS) and photobiostimulation using diode LASER, prior to local anaesthesia administration in children undergoing bilateral orthodontic extractions. A split-mouth, parallel arm, Double blinded, randomized clinical trial was conducted on children (12 - 16 yrs) undergoing bilateral orthodontic extractions. Patients were randomly assigned to receive either TENS or PBST. Subjective and Objective parameters for anxiety and pain were assessed, and evaluated for statistical significance (p < 0.05). In this study with 104 patients (mean age 13.59), the TENS group showed significantly lower mean pain scores (WBPRS) for needle insertion (2.30 ± 2.7) versus PBST (5.03 ± 3.1, p < 0.01), LA administration (2.11 ± 2.8 vs. 4.84 ± 2.7, p < 0.01), and extraction (1.92 ± 2.6 vs. 3.23 ± 5.1, p < 0.01). TENS also led to a faster onset of local anesthesia (96.15 s ± 13.9) compared to PBST (155.38 s ± 91, p < 0.05), indicating enhanced efficacy for pain reduction and anesthesia speed. Physiological parameters like pulse rate and salivary pH also showed significant improvements with TENS. Hence TENS and PBST both came out as effective alternatives for topical anesthesia. Both TENS and PBST proved to be effective alternatives to topical anesthesia, TENS therapy with the Synapse Dental Pain Eraser (DPE) demonstrated greater effectiveness in reducing pain and anxiety, reflecting it as a promising option for pediatric patients. However further research is needed to refine and optimize pain management strategies using these alternatives in pediatric dentistry. CTRI Number- CTRI/2022/09/045460 [Registered on: 13/09/2022] Trial Registered Prospectively.

Efficacy of photobiomodulation therapy on pain perception reduction associated with dental anesthetic infiltration injection: A systematic review and meta-analysis

Dental anesthetic injections, a common source of patient discomfort, often deter individuals from seeking dental care. Recently, there has been a growing focus on photobiomodulation therapy (PBMT) and its potential role in pain reduction. This systematic review explored the efficacy of PBMT in alleviating pain associated with dental anesthetic infiltration injections. A systematic literature search of different databases was performed up to December, 2023 using specific search strategy to find eligible studies that assessed the impact of PBMT on pain during local anesthesia injections. Data extraction was done based on the inclusion/exclusion criteria. A total of 13 studies, involving 972 patients were included. The studies employed various PBMT parameters, including wavelengths, and energy densities. Meta-analyses revealed a significant reduction in pain with PBMT compared to controls (MD = -0.90, 95% CI: -1.36 to -0.44, and p = 0.0001), with notable heterogeneity (I2 = 91.79%). Stratified analyses by age demonstrated consistent pain reduction in both adults (MD = -0.59, 95% CI: -1.11 to -0.08, and p < 0.0001) and children (MD = -0.59, 95% CI: -1.11 to -0.08, and p = 0.025). In conclusion, it seems that PBMT using infrared diode lasers can effectively reduce injection pain in both pediatric and adult populations. Further research should focus on optimizing PBMT parameters for enhanced pain management during dental procedures.

Effect of intraoral photobiomodulation therapy on pain perception associated with local anaesthesia infiltration: a systematic review and meta-analysis of randomized controlled trials

Local anaesthetic injections, commonly used in dentistry and oral surgery, often cause discomfort. This review aimed to examine the impact of intraoral photobiomodulation therapy (PBMT) on pain associated with local anaesthesia. Up to March 2024, two independent reviewers searched four databases, ultimately screening 17 randomized controlled trials for meta-analysis using Stata 17.0. The results indicate that intraoral PBMT application significantly reduces the perception of pain associated with local anaesthetic injections (standardized mean difference (SMD) -0.89, 95% confidence interval (CI) -1.27 to -0.52; P < 0.001). This analgesic effect remained consistent irrespective of concurrent topical anaesthetics, and PBMT was efficacious in paediatric (SMD -0.53, 95% CI -0.89 to -0.17; P = 0.004) and adult (SMD -1.46, 95% CI -2.32 to -0.61; P = 0.001) populations. Subgroup analysis provided very low to low-quality evidence that using a wavelength between 900 nm and 980 nm (SMD -0.87, 95% CI -1.36 to -0.39; P < 0.001) and an irradiation time of 13-40 s (SMD -0.94, 95% CI -1.35 to -0.53; P < 0.001) are associated with significant pain reduction. The use of PBMT could aid in reducing pain perception for patients during dental injections, encouraging earlier presentation for dental consultations.

The efficacy of photobiomodulation on dental injection pain: a systematic review of randomized clinical trials

Dental injections are routinely performed and can result in pain and anxiety in patients. This systematic review aimed to evaluate the efficacy of photobiomodulation therapy (PBMT) in dental injections for pain management in patients undergoing dental treatment. Indexed databases, including PubMed, EMBASE, Scopus, ISI Web of Knowledge, and Cochrane Library, were electronically searched without a time limit up to February 2024. A risk of bias evaluation was performed using the Cochrane tool. A preliminary investigation using electronic and manual methods yielded 4,920,881 manuscripts. Based on the eligibility requirements, 13 randomized control trials (RCTs) were included. Self-assessed pain was determined using the visual analog scale, Face, Legs, Activity, Cry, Controllability scale, or Wong-Baker face pain scale. Eight RCTs demonstrated a notable decrease in needle pain in patients undergoing dental needle injections using PBMT. Based on current evidence, PBMT may help reduce needle pain related to dental anesthesia. Further standardized studies are needed to assess the significance of PBMT for postoperative pain in patients undergoing dental injections.

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 prophylactic effect of photobiomodulation therapy on pain perception due to infiltration injection: a randomized clinical trial

OBJECTIVES

Fear of pain in dentistry especially the injection involved in most of the processes has always been an important issue preventing the patients from consulting a dentist at the right time. This study aims to evaluate the effect of photobiomodulation therapy on reduction of pain in infiltration injection.

MATERIALS AND METHODS

This trial is a crossover study including 30 patients. The patients are divided into two groups (laser therapy in the first period and placebo effect in the next period or vice versa with split-mouth design) using the covariate adaptive randomization method. All the patients received bilateral maxillary canine anesthesia in two periods performed with an ICT injection device (amount of anesthesia solution loaded: 1.8 mL) at a speed of 1 mL/min and a temperature of the solution of 37 °C. In each period, patients received either a prophylactic dose of 940-nm laser (500 mW, 10 J/cm2) or its placebo effect before the injection. The degree of pain perception after each sort of treatment is evaluated by both SEM (Sound, Eye, Motor, and Pain) and VAS (Visual Analogue Scale) scales.

RESULTS

According to analysis, all the patients scored a VAS scale under 3 in the period they received intervention. Also considering the SEM scale, most of the patients scored 0 in the intervention period. No adverse effect was reported during or after the process.

CONCLUSIONS

The study showed a significant effect of photobiomodulation on reducing pain perception during infiltration injection.

CLINICAL RELEVANCE

This method can be useful in order to lower the pain for the patients consulting a dentist and therefore facilitate consulting at early stages of the dental issues.

TRIAL REGISTRATION

The registration number (date) of the clinical trial in a Primary Registry in the WHO Registry Network is IR.ARAKMU.REC.1398.248(13/03/2020). The related URL is https://en.irct.ir/trial/45362 .

Low-level Laser Therapy to Alleviate Pain of Local Anesthesia Injection in Children: A Randomized Control Trial

Aim

The aim of our study was to evaluate and compare pain perception following photobiomodulation (PBM), topical anesthesia, precooling of the injection site, and vibration during administration of local anesthesia injection in pediatric patients aged 6-13 years.

Materials and methods

In this split-mouth study, a total of 120 patients between the age group of 6 and 13 years were selected and randomly divided into three equal groups with 40 subjects in each. Pain was assessed using visual analog scale (VAS) and the Wong-Baker Faces Pain Rating Scale after the administration of local anesthesia. Behavior during the procedure was assessed using the Face, Legs, Activity, Cry, Consolability (FLACC) scale filled by the operator. Pulse rate was recorded before and during the administration of local anesthesia using pulse oximeter. After the procedure, patient compliance was also recorded using validated questionnaire. The level of significance was set at p < 0.05.

Results

The study showed PBM exhibited the lowest mean scores of anxiety/pain using VAS, Wong-Baker Faces Pain Rating Scale, FLACC scale and pulse rate as compared to precooling, vibration, and topical anesthesia. The differences in pain scores recorded were found to be statistically significant. Children were not anxious about the PBM method and exhibited good compliance (p < 0.001).

Conclusion

Photobiomodulation (PBM) was found to be effective means of reducing injection pain, demonstrating much better efficacy than other tested methods.

Clinical significance

Photobiomodulation (PBM) can be used effectively to better manage procedures that patients frequently find painful without the need for prescription drugs, which frequently have several side effects.

How to cite this article

Khan BS, Setty JV, Srinivasan I, et al. Low-level Laser Therapy to Alleviate Pain of Local Anesthesia Injection in Children: A Randomized Control Trial. Int J Clin Pediatr Dent 2023;16(S-3):S283-S287.

Effect of a needle-free system versus traditional anesthesia on pain perception during palatal injections in children

BACKGROUND

Needle-free injection systems can contribute to the prevention of needle-related pain during palatal infiltration anesthesia (PIA) in children. Research on this topic in children is required.

AIM

The purpose of this clinical study was to evaluate the effectiveness and patient preference of a needle-free system versus traditional anesthesia (TA) on pain perception during PIA in children.

DESIGN

The study was designed as a randomized, controlled crossover clinical study with 48 children aged 6-12 years requiring dental treatment with PIA in bilateral maxillary primary molars. TA was applied on one side and the Comfort-in™ injection system (CIS) on the other side in two separate sessions. Then, patient preference was recorded. The pain perception during PIA was evaluated using the Wong-Baker FACES Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability (FLACC) Scale. The data were analyzed for statistical significance (p < .05).

RESULTS

There were statistically significant differences between the TA and the CIS according to the PRS and FLACC Scale scores. On both scales, significantly higher pain ratings were observed in the TA group during PIA (p < .001). There was a statistically significant difference in terms of patient preference (p < .001). Although 77.1% (n = 37) of the children preferred the CIS, 22.9% (n = 11) preferred the TA. Moreover, patient preference for the CIS was significantly higher in older children (p < .01).

CONCLUSIONS

The application of a needle-free system during PIA ensured a decrease in pain perception in children.

Evaluation of the effects of photobiomodulation with different laser application doses on injection pain in children: a randomized clinical trial

The utilization of photobiomodulation (PBM) to decrease the experience of pain during the application of local anesthesia (LA) has been reported in a limited number of studies with children. However, currently, there is no complete consensus regarding its efficacy and application doses. The objective of the clinical trial was to assess the effects of PBM with three different laser application doses (with different power values) plus 10% lidocaine topical anesthetic and to compare them with placebo + 10% lidocaine topical anesthetic on LA injection pain in children. A prospective, parallel-arm, randomized, triple-blind clinical trial was conducted with 160 children aged 6 to 12 years (79 girls and 81 boys; 80 maxillary and 80 mandibular primary first molars). The children were divided into 4 groups with an equal number of subjects in each group. Before topical anesthetic usage, a laser with a power of 0.3 W, 0.4 W, and 0.5 W was applied in Groups 1, 2, and 3, respectively (a diode laser: 940 nm; continuous mode; 20 s for each group). The energy density was calculated as 69 J/cm2, 92 J/cm2, and 115 J/cm2. A placebo laser was used in the fourth group. Injection pain was assessed subjectively and objectively with the Wong-Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability (FLACC) Scale. The data were analyzed using the Chi-square test (P < 0.05). The mean (± std) PRS scores were 1.35 ± 1.075, 1.37 ± 1.05, 1.07 ± 1.04, and 2.07 ± 1.09 for Groups 1, 2, and 3 and the placebo group, respectively. Additionally, the mean (± std) FLACC scores were 1.67 ± 1.50, 1.62 ± 1.90, 1.35 ± 1.74, and 2.75 ± 1.64 for Groups 1, 2, and 3 and the placebo group, respectively. Groups 1, 2, and 3 showed significantly lower pain scores than the placebo group (P = 0.02). However, no significant difference was observed between Groups 1, 2, and 3 according to either pain scale score (P = 0.948). In addition, no relationship was found in pain scores related to sex and jaw differences in any group (P = 0.321, P = 0.248). PBM delivered by a 940-nm diode laser plus 10% lidocaine topical anesthetic before the application of LA decreased injection pain regardless of the applied laser dose in this study.

The 1064-nm Nd: YAG Photobiomodulation vs. 20% Benzocaine Topical Gel in Inducing Mucosal Anesthetic Effect: A Double-Blind Randomized Clinical Trial

The periapical local anesthetic injection may be associated with fear of needles and pain administration. Dental topical anesthetic agents can help to reduce pain perception; however, adverse events can occur. To investigate the efficacy of 1064-nm photobiomodualtion (PBM) in inducing mucosal anesthesia delivered with a flat-top hand-piece compared to 20% Benzocaine topical anesthetic gel, sixty healthy patients were randomly allocated (1:1) to either 20% benzocaine topical gel + placebo laser (T group) or PBM + placebo gel (L group). The 1064-nm Nd:YAG laser was employed and is associated with a novel flat-top hand piece. The applied operational parameters were 0.5 W, 10 Hz, 100 µs pulse width, and 30 J/cm2 for one-minute single application time. The enrolled subjects were asked to assess pain intensity at the time of anesthetic injection with a Visual Analog Scale. Taking into consideration taste, undesirable numbness, and overall satisfaction, the patients were asked to rate their experiences according to a verbal rating scale. Statistical analysis showed no statistically significant difference between the T and L Groups for pain ratings (p = 0.0596). The L Group displayed significantly higher ratings than T Group for taste, undesirable numbness, and overall satisfaction (p < 0.001). The 1064-nm PBM delivered by flat-top hand piece is effective in inducing mucosal anesthesia, eliminating the adverse side-effects of the conventional topical anesthetic gel.

Effects of low level laser therapy on injection pain and anesthesia efficacy during local anesthesia in children: A randomized clinical trial

BACKGROUND

The use of low level laser therapy (LLLT) to reduce injection pain associated with dental local anesthesia is reported in a limited number of studies in adults, but research on the effects of LLLT in children is needed.

AIM

This study aimed to evaluate the effects of topical anesthesia + LLLT on injection pain, anesthesia efficacy, and duration in local anesthesia of children who are undergoing pulpotomy treatment.

DESIGN

The study was conducted as a randomized, controlled-crossover, double-blind clinical trial with 60 children aged 6-9 years. Before local infiltration anesthesia was administered, only topical anesthesia was applied in one side (control group/CG), and topical anesthesia plus LLLT (a diode laser: 810 nm; continuous mode; 0.3W; 20 s; 69 J/cm² ) was applied in the contralateral side (LG) as pre-anesthesia. The injection pain and anesthesia efficacy were evaluated subjectively and objectively using the Wong-Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability (FLACC) scale respectively. Data were analyzed for statistical significance (p < .05).

RESULTS

The "no pain" and "severe pain" rates in the PRS were 41.7% and 3.3% for the LG and 21.7% and 11.7% for the CG, respectively, during injection. Similarly, in the FLACC data, the number of "no pain" responses was higher for the LG than the CG (40%, 33.3%) and no "severe pain" rate was observed in both groups. The only statistically significant difference found for the PRS was p < .05. The median pain score was "0" for the LG and the CG in the FLACC data for the evaluation of anesthesia efficacy, and there was no statistically significant difference between the groups in terms of pain and anesthesia duration (p > .05). Also, most of the children preferred injection with topical anesthesia + LLLT (66.7%).

CONCLUSIONS

It has been determined that the application of topical anesthesia + LLLT with an 810-nm diode laser before local infiltration anesthesia reduced injection pain and did not have an effect on anesthesia efficacy and duration in children.

Prospective Study on PDL Anesthesia as an Aide to Decrease Palatal Infiltration Pain

OBJECTIVE

The purpose of this prospective randomized study was to assess using a periodontal ligament (PDL) injection as an aide to decrease palatal infiltration pain.

METHODS

A total of 133 subjects randomly received a PDL injection and alternative palatal infiltration or a mock PDL injection and conventional palatal infiltration at 2 separate appointments. PDL injection was given in the mid-palatal sulcus of the maxillary first molar. Mock PDL injection consisted of only needle insertion. All subjects then received a palatal infiltration administered into the blanched gingival tissue 3 mm (alternative palatal infiltration) or 7 mm (conventional palatal infiltration) from the gingival collar. Subjects recorded needle insertion and solution deposition pain using a Heft-Parker visual analog scale (VAS).

RESULTS

The combined PDL injection and alternative palatal infiltration had significantly decreased mean VAS ratings for needle insertion and solution deposition pain (P < .0001). Incidence of moderate/severe pain for needle insertion and solution deposition was reduced from 65% to 1% and from 65% to 2%, respectively.

CONCLUSION

Providing PDL anesthesia into the mid-palatal sulcus of the maxillary first molar and then administering an alternative palatal infiltration into the blanched collar around the PDL molar site led to significant reductions in needle insertion and solution deposition pain compared with a mock PDL and conventional palatal infiltration.

Evaluating the Preemptive Analgesic Effect of Photo-biomodulation Therapy on Pain Perception During Local Anesthesia Injection in Children: A Split-mouth Triple-blind Randomized Controlled Clinical Trial

To evaluate the impact of photobiomodulation therapy (PBMT) on injection pain perception and compare it with a topical oral anesthetic gel. A total of 30 patients of six to nine years old seeking pulpotomy treatment of maxillary secondary primary molars of both sides were considered for this split-mouth triple-blind randomized clinical trial. On one side of the maxilla, the low-level-laser (diode laser, 808 nm, 250 mW; 16.25 J; 32.5 J/cm² ) was irradiated upon the buccal gingiva of the tooth, while a Benzocaine 20% topical anesthetic gel was applied on the other side. A gel with the same taste (strawberry) was applied for the placebo. The Wong-Baker Faces Pain Rating Scale was used to evaluate the injection pain and post-operation pain at two timestamps, one hour and 24 hours after treatment. Patients' heart rate was also evaluated. Paired-T, Wilcoxon-signed-rank test, McNemar and Friedman tests were used for statistical analyses. Results demonstrated that PBMT could significantly decrease the injection pain perception and heart rate alternations compared to the topical anesthetic gels (P=0.000). However, no significant differences were documented between the two methods concerning the 1hour (P=0.26) and 24-hours (P=1.00) post-operation pain. PBMT can be an effective non-pharmacological technique for controlling injection pain.

An Efficacy of Photobiomodulation of 850 nm on Pain Reduction in a Human Oral Capsaicin Pain Model

Objective: The aim of this clinical trial was to evaluate the efficacy of photobiomodulation (PBM) to reduce oral pain initiated by capsaicin. Background: PBM has been used for pain reduction in oral regions; however, its clinical efficacy to alleviate burning sensations is still unknown. Methods: This clinical study was divided into two phases. There were 10 subjects in each phase. In Phase I, the burning sensation was stimulated using 0.05% in 95% ethanol capsaicin (prepared by the Faculty of Pharmaceutical Sciences, Khon Kaen University, Thailand) on filter paper and recorded with a 10-cm horizontal visual analog scale (VAS) every 1 min until the subject experienced no more pain. The area under the curve (AUC) of the graph between VAS and time was calculated. The washout period was 24 h. In Phase II, a crossover clinical trial was conducted in subjects who received the pain model as stated. Four interventions were included: (1) PBM before & after pain stimulation, (2) PBM before pain stimulation, (3) PBM after pain stimulation, and (4) Placebo. For PBM intervention, a single exposure of 850 nm Laser (AsGaAl; TOP 250 Soft Laser, Berkmed Medikal, distributed by Medical Innovation-MI, Istanbul, Turkey) with 0.10 cm² spot size laser probe continuous wave at 1 W/cm² and 30 J/cm² for 30 sec was used. Results: In Phase I, there was no statistically significant difference (p = 0.09) between the average AUC of day 1 [55.63 (23.38)] and day 2 [48.99 (27.20)]. In phase II, there was no statistical difference (p = 0.20) of the average AUC among the interventions and the placebo; group 1 [56.24 (30.11)], group 2 [45.46 (45.46)], group 3 [64.15 (32.89)], and group 4 [58.59 (30.16)]. Conclusions: The human capsaicin model was suitable for a crossover design clinical trial. The PBM used in this study did not reduce oral burning sensations from capsaicin.

Effectiveness of Pre-cooling the Injection Site, Laser Biostimulation, and Topical Local Anesthetic Gel in Reduction of Local Anesthesia Injection Pain in Children

Aim and objective

Evaluation of the effectiveness of laser biostimulation (LBS), ice, and local anesthetic (LA) gel in reducing the injection pain during administration of local anesthesia in children.

Materials and methods

A 3-arm, crossover randomized controlled trial included 30 children of age 9-12 years requiring extraction of primary maxillary posterior teeth. Children were randomly allocated to 3 groups of 10 each. After proper isolation and drying of the buccal mucosa, one of the three techniques, i.e., either LBS or ice or LA gel was applied for 1 minute followed by administration of the LA solution. The pain response was assessed using Wong-Baker Faces Pain Rating Scale and the Sound Eyes Motor scale (SEM). Kruskal-Wallis ANOVA and Mann-Whitney U tests were performed for intragroup and intergroup comparisons, respectively.

Results

Lower pain score of zero suggesting no hurt was given by more children in the ice group, followed by LA gel and LBS groups in both the scales. The differences in pain scores recorded were found to be statistically significant.

Conclusion

Ice is found to be equally effective as LA gel, whereas low-level laser therapy is less effective compared to the other two techniques in reducing the injection pain during administration of maxillary posterior buccal infiltration in children.

Clinical significance

Pain management during LA injection is a critical step in gaining initial trust and during the subsequent treatment visits. The present study suggests that simple methods like pre-cooling the injection site with ice can be used as an effective non-pharmacological technique to reduce injection pain.

How to cite this article

AmruthaVarshini I, Vinay C, Uloopi KS, et al. Effectiveness of Pre-cooling the Injection Site, Laser Biostimulation, and Topical Local Anesthetic Gel in Reduction of Local Anesthesia Injection Pain in Children. Int J Clin Pediatr Dent 2021;14(1):81-83.

Effect of photobiomodulation on pain level during local anesthesia injection: a randomized clinical trial

The aim of this study was to investigate the effect of photobiomodulation therapy (PBMT) as pre-treatment on pain level during injection in the anterior maxillary region. 56 Patients were randomly divided into 3 groups, Group 1:980 nm diode laser (n = 22) (experimental), Group 2:980 nm diode laser probe placed in vestibule without radiation (placebo) (n = 22), Group3: no pre-treatment before injection (n = 12) (control). Pain level during injection was evaluated by visual analog scale (VAS). The severity of pain in Group 1(experimental) and Group 2 (placebo) was significantly lower than Group 3 (control). Group 1 had a lesser pain level than Group 2, but the difference in pain level between them was not significant. PBMT with 980 nm wavelength decreased pain level during local anesthesia injection without superiority over placebo.