Effect of Root Canal Disinfection with a Diode Laser on Postoperative Pain After Endodontic Retreatment

Efficacy of laser adjuvant therapy in the management of post-operative endodontic pain: A systematic review and meta-analysis

BACKGROUND

Postoperative endodontic pain (PEP) is crucial in clinical practice. Recently, the effects of various laser adjuvant therapies in endodontic treatments have been widely evaluated. However, as a virtually side-effect-free treatment, its effect on postoperative pain management during endodontic treatment remains controversial.

OBJECTIVES

This review aimed to compare the efficacy of laser adjuvant therapy for pain management after endodontic treatment.

METHOD

The Cochrane Library, PubMed, Embase, Scopus and Web of Science databases were systematically searched for articles published until 12 February 2023. The risk of bias in the included studies was evaluated based on the Cochrane risk-of-bias assessment tool. Data on continuous outcomes of visual analogue scale pain scores are expressed as standard mean difference (SMD) and dichotomous outcomes of pain prevalence as relative risk (RR).

RESULTS

We included 22 studies, of which 15 enrolled 892 patients with visual analogue scale pain scores and 7 enrolled 422 patients with pain prevalence. Of the 22 studies, seven studies had a low risk of bias, 10 had a moderate risk of bias and 5 had a high risk of bias. For pain level, the pooled outcomes indicated reduced pain scores in all laser adjuvant therapy, including low-level laser therapy (SMD = -0.86 [95% CI: -1.16, -0.55] in 24 h and SMD = -0.64 [95% CI: -0.84, -0.43] in 48 h), diode laser therapy (SMD = -0.27 [95% CI: -0.50, -0.04] in 48 h) and photodynamic therapy (SMD = -1.12 [95% CI: -2.18, -0.05] in 24 h). For postoperative pain incidence, a significant correlation was observed with reduced pain incidence rates in the photodynamic therapy group (pooled RR = 0.47 [95% CI: 0.31, 0.72]) but not in the low-level laser therapy group (RR = 0.89 [95% CI: 0.30, 2.70] at 12 h and RR = 0.57 [95% CI: 0.09, 3.72] at 24 h).

CONCLUSIONS

High-quality evidence suggests that laser adjuvant therapies such as low-level laser therapy, diode laser therapy and photodynamic therapy have a positive impact on reducing postoperative endodontic pain intensity. However, the differences in PEP management effects between laser therapies are unknown, and no significant differences were observed among the subgroups.

REGISTRATION

CRD 42023402872 (PROSPERO).

Lasers efficacy in pain management after primary and secondary endodontic treatment: a systematic review and meta-analysis of randomized clinical trials

Postoperative pain is a common concern following root canal treatments (RCT), impacting both patients and oral health practitioners. This systematic review and meta-analysis aimed to evaluate the effectiveness of laser treatment modalities in reducing postoperative pain compared to conventional methods after primary and secondary RCT in permanent mature teeth. A search of three electronic databases (PubMed, ScienceDirect, and The Cochrane Library) was conducted, using a broad range of keywords and terms. Gray literature and manual searches were conducted to complement the search. The inclusion criteria included randomized clinical trials based on the objective of the secondary study. A minimum sample size of 10 participants per group and a clearly defined criterion for postoperative pain assessment were required. The characteristics of the included studies were presented as tables. The Cochrane collaboration tool RoB 2.0 was used to assess the risk of bias within each study. Two reviewers extracted the data and assessed the studies independently, and discrepancies were resolved through consultation with a third reviewer. A random-effects model was employed for meta-analysis to estimate the overall effect measure. Heterogeneity was evaluated using Cochran's Q test and the I2 index. Publication bias was explored via Funnel plots and Egger's test. Subgroup analyses and meta-regression were conducted to assess variations among laser methods and examine the influence of independent factors. The significance threshold for all analyses was set at 5% (α = 0.05). Intraoral laser therapy demonstrated no significant advantage over conventional treatments but consistently outperformed placebo, particularly from 4 to 72 h post-treatment. Low-level laser therapy provided slight pain reduction in the first 8 h, though its effectiveness diminished in retreatment scenarios. Photodynamic therapy and laser disinfection showed marginal benefits, especially shortly after treatment, with reduced efficacy in longer-term or retreatment contexts. Further research is needed to explore different applications of laser modalities and assess distinct prognostic factors in more detail.

The cutting-edge roles of lasers in endodontics: A bibliometric and scientometric analysis of the 100 most-cited articles

PURPOSE

This bibliometric and scientometric analysis aimed to delve into the forefront roles of lasers in endodontics from 1990 to 2024.

METHODS

A comprehensive electronic search was conducted using "Clarivate Analytics Web of Science, All Databases" to retrieve the most-cited articles pertaining to the topic. These articles were then ranked in descending order according to their citation counts and the top 100 were selected for further analysis. Parameters including citation density, publication year, journal, journal impact factor (IF), country, institution, author, study design, study field, evidence level, laser type, and keywords were meticulously analyzed.

RESULTS

The mean and standard deviations of total citation and citation density were 106.47 ± 65.76 and 7.61 ± 5.13, respectively. Positive and negative correlations were found between the number of citations and citation density and age of publication. While the mean number of citations was significantly higher in the period 2001-2010 compared to the other periods (P < 0.05), values were similar between the periods 1990-2000 and 2011-2014 (P > 0.05). Articles were mainly published in the Journal of Endodontics. The most productive country, institutions, and author were the United States, the University of Showa, and Koukichi Matsumoto. Diode and Er: YAG lasers were commonly investigated. Ex vivo studies were mainly performed followed by in vitro ones. The main study field was "antimicrobial effect". Among keywords, "photodynamic therapy" was used more frequently.

CONCLUSION

Lasers are predominantly utilized to leverage their antimicrobial efficacy. Advancements in technology will lead to improvements in the properties of lasers, thereby enhancing the disinfection of the root canal system.

A 980 nm Diode Laser as an Adjunctive Therapy on the Healing of Apical Periodontitis Following Endodontic Retreatment: A Randomized Controlled Clinical Trial Study

Introduction: Apical periodontitis is one of the common dental diseases. Microorganisms are the main reasons for these lesions; irrigations are used to remove them, but because of limited penetration, the rinsing agents may not always kill the microorganisms. Laser irradiation is effective in canal disinfection. The goal of this study was to compare the effect of calcium hydroxide (Ca(OH)2 ) and diode laser on the improvement of apical periodontitis following root canal retreatment (RCR). Methods: Twenty-four teeth of 19 patients with periapical lesions which needed RCR were divided into two groups (Ca(OH)2 and Ca(OH)2+laser irradiation [LI]). In the first session, after gutta-percha removal, cleaning, and shaping, Ca(OH)2 was used for 10 days. In the second session, in the Ca(OH)2+LI group, the irradiation utilizing a diode laser (using non-initiated 200-µm fiber, continuous wave (CW), power output of 1W) was done. The periapical radiographic healing was assessed before the retreatment and after 3-month and 6-month follow-ups by periapical index (PAI) Qrstavik. The quantitative data were analyzed (P<0.05). Results: The initial periapical lesion score was 3.75 and 3.88 in the Ca(OH)2 and Ca(OH)2+LI groups, respectively. In the Ca(OH)2 and Ca(OH)2+LI groups, 3 months after the RCR, the average periapical lesion score was 2.94 and 3.05, respectively. In the Ca(OH)2 and CA(OH)2+LI groups, 6 months after the RCR, the average periapical lesion score was 1.80 and 1.75, respectively. No significant differences were found at the 3 and 6 months between the experimental groups. Conclusion: The diode laser can reduce the periapical lesion, but there was no significant difference between CA(OH)2+LI and Ca(OH)2 at 3-month and 6-month follow-ups.

A systematic review and meta-analysis on the effects of phototherapy on postoperative pain in conventional endodontic reintervention

OBJECTIVES

This systematic review and meta-analysis (SRM) aimed to evaluate the efficacy of laser phototherapy (LPT) on the reduction in postoperative pain (PP) of endodontic origin after conventional/non-surgical reintervention of root canals.

METHODS

This SRM was registered with PROSPERO (CRD42021243500) and followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Meta-analysis was conducted using R software with the "META" package, the mean difference (MD) measure of effect was calculated, and the fixed effect model was applied with a 95% confidence interval (CI). The Cochrane collaboration scale was used to assess the risk of bias and the GRADE tool to assess the quality of evidence.

RESULTS

Initially, 1028 articles were found, and five articles were included. Most studies were classified as "low" risk of bias. Of the five clinical studies, four showed a significant decrease in PP after endodontic reintervention in the LPT groups compared to the control group, especially in the first four days after the intervention. In symptomatic teeth with multiple roots, LPT led to less PP at 24 h (MD -0.52 [-1.03; -0.02] p = .04). However, no significant difference between the groups was found at 48 and 72 h (p > .05). The certainty of the evidence was classified as low.

CONCLUSION

Despite the limitations of this SRM, LPT was shown to be a promising alternative for reducing and controlling PP in conventional endodontic reintervention.

CLINICAL SIGNIFICANCE

The use of LPT in endodontic reintervention may be a safe and promising alternative to clinically efficacious agent for use in the management of PP in this procedure.

Incidence of Postoperative Flare-Up After Single-Visit and Multi-visit Endodontic Therapy

This article presents results obtained from a survey, including patients who underwent endodontic treatment by the single-visit or multi-visit method, after confirmation of the diagnosis of chronic apical periodontitis.

OBJECTIVE

The aim of the survey was to obtain data from the studied patients on the frequency and the type of postoperative pain after treatment of chronic apical periodontitis, as well as whether there is a relation between gender, age, and postoperative pain.

MATERIALS AND METHODS

A visual analog scale was used to study the intensity of postoperative pain in the treatment of teeth diagnosed with CPP, which are treated by one of two methods - single-visit or multi-visit method. The total number of surveyed patients is 71. The patients were examined and treated at the Dental Clinic "Imperial" in Varna, Bulgaria, in 2020. Thirty-one of them were treated by the single-visit method, and the remaining 40 by the multi-visit method with placement of a temporary dressing or sterile swab.

RESULTS

A relatively large proportion (70%) of patients reported mild pain immediately after the root canal filling. A relatively large proportion (90.3%) of patients did not report pain one week after the root canal filling. The more frequent symptoms were observed in cases treated by the multi-visit method, after the application of a temporary dressing. Patients who reported taking analgesics were treated in the multi-visit method. More frequent pain symptoms with both methods of treatment were observed in men aged 36-60 years.

CONCLUSION

Although exacerbation has been shown to have no significant effect on the outcome of endodontic treatment, it is highly undesirable. In the short term, the postoperative pain in patients treated by the multi-visit method through the use of intracanal medication is more pronounced. Patients receiving the single-visit treatment reported less postoperative pain.

Wound healing after therapy of oral potentially malignant disorders with a 445-nm semiconductor laser: a randomized clinical trial

OBJECTIVES

Oral potentially malignant disorders (OPMDs) are the most clinically relevant precursor lesions of the oral squamous cell carcinoma (OSCC). OSCC is one of the 15 most common cancers worldwide. OSCC is with its high rate of mortality an important cause of death worldwide. The diagnosis and therapy of clinically relevant precursor lesions of the OSCC is one of the main parts of prevention of this malignant disease. Targeted therapy is one of the main challenges concerning an oncologically safe tissue removal without overwhelming functional and aesthetic impairment.

MATERIALS AND METHODS

In this randomized controlled trial, a newly introduced intraoral 445-nm semiconductor laser (2W; cw-mode; SIROLaser Blue, Dentsply Sirona, Bensheim, Germany) was used in the therapy of OPMDs. Duration and course of wound healing, pain, and scar tissue formation were compared to classical cold blade removal with primary suture by measuring remaining wound area, tissue colorimetry, and visual analogue scale. The study includes 40 patients randomized using a random spreadsheet sequence in two groups (n1 = 20; n2 = 20).

RESULTS

This comparative analysis revealed a significantly reduced remaining wound area after 1, 2, and 4 weeks in the laser group compared to the cold blade group (p < 0.05). In the laser group, a significantly reduced postoperative pain after 1 week was measured (p < 0.05).

CONCLUSION

Laser coagulation of OPMDs with the investigated 445-nm semiconductor laser is a safe, gentle, and predictable surgical procedure with beneficial wound healing and reduced postoperative discomfort.

CLINICAL RELEVANCE

Compared to the more invasive and bloody cold blade removal with scalpel, the 445-nm semiconductor laser could be a new functional less traumatic tool in the therapy of OPMDs. The method should be further investigated with regard to the identification of further possible indications.

TRAIL REGISTRATION

German Clinical Trials Register No: DRKS00032626.

Current Applications and Future Directions of Lasers in Endodontics: A Narrative Review

The utilization of lasers has been regarded as a novel technique for the purposes of clinical use in the dental field. Recently, numerous studies have been conducted on the potential applications of laser therapy in endodontics. Moreover, due to their ablation, penetrability, and disinfection capabilities, lasers have performed well with respect to endodontic treatments, including root canal treatment, vital pulp therapy (pulp capping and pulpotomy), dentinal hypersensitivity treatment, and management of dental pain related to pulp and periradicular disease. In particular, the superiorities of laser-aided pulp therapy are emphasized through condensed clinical controlled trials, and histological studies, in this review. Moreover, the ingenious use of laser applications with respect to aiding in the acceleration of root development and the extraction of foreign matters (i.e., broken files and fiber posts) in canals has quickly become the cutting-edge trend of current research. This review offers a summary and discussion of the current literature on all the aforementioned laser applications. Moreover, the characteristics of laser devices, including erbium lasers, neodymium-doped lasers, CO2 lasers, and diode lasers, are detailed and discussed here, providing useful references for laser application in endodontics. We also focus on the different wavelengths with respect to the lasers that are applied in endodontics. High-power lasers perform well as operative instruments; in addition, low-level lasers lead to the regulation of pulp inflammation, and the promotion of pulp healing. This narrative review provides a summary of the advanced applications of lasers in conjunction with various devices in the practice of endodontics, and aims to inspire innovative perspectives on lasers in the context of the treatment of dental diseases, especially pulp diseases, in the future.

Adjuvant therapy with a 980-nm diode laser in root canal retreatment: randomized clinical trial with 1-year follow-up

The purpose of this study is to assess the laser effect in root canal disinfection and periapical healing of endodontically treated teeth from patients with asymptomatic apical periodontitis. This study was performed as a randomized clinical trial. Thirty patients were selected according to the inclusion/exclusion criteria. Fifteen patients received the root canal retreatment (RCR) combined with 980-nm diode laser irradiation (LI). The canals were irrigated with saline solution and gently dried with paper points, keeping the dentin partially moist. The irradiation was performed using a 320-µm-diameter fiber in helicoidal movements (pulsed mode, power output of 1.5 W, 100 Hz for 20 s). The other 15 patients received the RCR with placebo irradiation (PI). Microbiological samples were taken in three periods: S1, after the filling material removal (baseline); S2, after laser or placebo irradiation (LI or PI); and S3, after the RCR followed by laser or placebo. The samples were submitted to the total microbial and E. faecalis counting. The periapical radiographic healing was analyzed after 3, 6, 9, and 12 months. Microbiological data (CFU/mg) were analyzed by ANOVA and Tukey's test (P < 0.05), and the repair by Mann-Whitney test (P < 0.05). In S2, the laser provided 42.44% microbial reduction and 53.14% of E. faecalis, different from the placebo that had no reduction, and 4.85% for Enterococcus (P < 0.05). In S3, the bacterial counts decreased without differences between groups. No differences in healing were found at 3 months. However, diode laser facilitated the repair from 3- to 12-month follow-up (P < 0.05) and had 45% more healed cases than placebo. Diode laser provided an antimicrobial effect before the biomechanical preparation but was not synergistic in RCR. It improved the periapical healing during follow-up.

Effect of EDDY and manual dynamic activation techniques on postoperative pain in non-surgical retreatment: a randomized controlled trial

BACKGROUND

During non-surgical retreatment process, the products such as dentin debris, root canal fillings, irrigation solutions, microorganisms and remaining pulp tissues can extrude to the apical area and can cause the postoperative pain and flare-up. Thus, the aim of this study was to evaluatethe effect of EDDY and manual dynamic activation (MDA) techniques on postoperative pain (PP) associated with retreatment.

METHODS

Ninety patients scheduled for retreatment were treated at a single visit. Non-vital mandibular premolar teeth diagnosed with asymptomatic apical periodontitis were included in this study. The patients were divided into two groups (n = 45) on the basis of the need for additional irrigation activation procedures (EDDY and MDA). The patients' post-treatment pain levels were asked to rate the intensity of their pain on a 10-point numerical rating scale (NRS) at the 12th, 24th, 48th, and 72nd h and 7 days.The data were analyzed using the chi-square and Wilcoxon signed-rank test was used for within-group comparisons and Mann Whitney U test was used to compare the groups by time period.

RESULTS

The difference in postoperative pain intensity between two groups was statistically significant at 12, 24, 48, and 72 h (p < 0.05). There was no significant difference at 7 days. Moreover, no statistically significant difference was found between the two groups in terms of gender and analgesic medication intake (p > 0.05). Pain intensity after the treatment was lesser in the MDA groupthanin the EDDY group at 12, 24, 48, and 72 h.

CONCLUSION

This study could lead us to conclude that the two activation systems can be used during endodontic retreatment with no difference at PP 7 days later. However, a comparison of the groups indicated that the EDDY resulted in significantly more PP at 12, 24, 48, and 72 h. Trial registration ClinicalTrials.gov Identifier: NCT04726670.

Comparative evaluation of postoperative pain following chemomechanical preparation of single-rooted nonvital teeth with symptomatic apical periodontitis with and without laser irradiation: A double-blind randomized placebo controlled clinical trial

Background

Postoperative pain can occur because of residual infection even after effective chemomechanical preparation. This study aimed to compare postoperative pain after chemomechanical preparation with placebo and laser irradiation in nonvital teeth having symptomatic apical periodontitis.

Materials and Methods

Sixty (n = 30) participants after obtaining written consent were enrolled in the study. In Group 1, chemomechanical preparation followed by mock laser therapy was carried out in which laser tip was applied but not activated. In Group 2, chemomechanical preparation followed by a laser irradiation was applied and activated. Postoperative pain scores were evaluated at baseline, 24 h, 48 h, and 72 h using the Visual Analog Scale. Preoperative and postoperative percussion pain scores were also recorded. Subjects needing rescue medication were recorded as well. Mann-Whitney U test and Wilcoxon test were used for intergroup comparison and intragroup comparison. The Chi-square test was used for comparing rescue medication.

Results

There was significant reduction in pain scores in the laser group as compared to placebo group at all time points. There was also significant difference in the preoperative and postoperative percussion pain scores. 9 and 3 subjects required rescue medication in Groups 1 and 2, respectively.

Conclusion

Laser irradiation following chemomechanical preparation led to significant reduction in postoperative pain and can be considered as a valuable adjunct.

Effect of Ultrasonic and Diode Laser Irrigation Activation on Post-operative Pain and Microbial Reduction in Single Visit Endodontic Treatment of Necrotic Mandibular Molars

Aim: To clinically evaluate the effect of continuous ultrasonic and diode laser 810 wave length irrigation activation techniques on postoperative pain and bacterial reduction in single visit endodontic treatment of mandibular molars. Material and methods: Forty patients requiring root canal treatment therapy for necrotic mandibular molars teeth were included in this study with age ranges between 20 and 45 years. In all cases, single visit endodontic treatment was carried out using Revo-S rotary file system in crown down sequence. NaOCl 2.5% irrigation solution was used during treatment. Patients were randomly and equally assigned into two groups according to irrigation technique. Group (1): conventional syringe irrigation and group (2): continuous ultrasonic irrigation. Each group was subdivided into two sub groups (n = 10); subgroup 1A (conventional syringe irrigation with no laser), subgroup 1B (conventional syringe irrigation with diode laser), subgroup 2A (continuous ultrasonic irrigation with no laser) and subgroup 2B (continuous ultrasonic irrigation with diode laser). Postoperative pain evaluation was done using Visual Analogue Scale (VAS) at 6, 12, 24, 36, 48 hours and 7 days postoperatively. Microbiological detection of bacterial reduction was done by taking Samples (S1 and S2) for bacterial cultures. S1 after finishing access cavity and before mechanical preparation and S2 after finishing mechanical preparation and irrigation activation and before obturation. Samples were cultured on blood agar and determined as colony forming units (CFU/mL). Microbiological bacterial reduction was calculated accordingly.  Statistical analyses were analyzed using the Mann-Whitney U test.  The significance level was set at p < 0.05. Results: In all sub groups, postoperative pain decreased by time in all time intervals but pain was significantly lower in subgroup (2B) (continuous ultrasonic irrigation with diode laser) than subgroup (1A) (conventional syringe irrigation with no laser) in all time interval. Microbiological results showed the highest bacterial reduction was in subgroup (2B) (continuous ultrasonic irrigation with diode laser) and least bacterial reduction was in subgroup (1A) (conventional syringe irrigation with no laser). Conclusion: Using diode laser and continuous ultrasonic irrigation activation techniques as adjunctive methods showed improvement in postoperative pain records and enhanced bacterial reduction in root canal therapy. Keywords: Continuous ultrasonic irrigation, diode laser 810, post-operative pain, bacterial reduction, single visit endodontic treatment.

Protocol for the clinical practice of photodynamic therapy in endodontics: assessment of guideline quality using the AGREE II instrument

BACKGROUND

The choice of parameters in Photodynamic Therapy for endodontic treatment, such as wavelength, energy, application time, and number of sessions can vary based on the characteristics of the procedure and the patient. Providing information supported by scientific evidence in an accessible way to clinicians who are unfamiliar with the literature is necessary. Thus, this study aimed to synthesize a clinical protocol for the use of photodynamic therapy in endodontics in permanent teeth.

METHODS

Protocols with high methodological quality were identified using a literature search and the Appraisal of Guidelines Research and Evaluation Instrument (AGREE II), a validated tool for assessing quality. The recommendations of these studies were synthesized and submitted to a group of experts for evaluation and adaptation, and consensus was assessed using the Delphi methodology.

RESULTS

The analysis of the literature on the application of antimicrobial photodynamic therapy in endodontics showed that clinical trials with good levels of evidence and clinical recommendations have been reported previously, with two studies identified as having a clinical recommendation level of A1A and an evidence level of A.

CONCLUSION

The written protocol was considered to be satisfactory and as having appropriate content validity during the second round of evaluation by the experts. The studies included in this research were predominantly explanatory in nature, highlighting the need for pragmatic designs to increase the degree of clinical applicability.

Endodontic postoperative flare-up: An update

Endodontic treatment corresponds to a combined chemical and mechanical approach, followed by a three dimensional hermetic obturation, that eliminate the pulpal and periradiculare disease and boost healing and repair of periradiculare tissue. Despite the advances in the endodontic field, the inter-appointment flare up remains a true nightmare that encounters every dentist. This complication commences a few hours or days after root canal procedures and it is characterized by the development of pain and/or swelling, requiring an unscheduled appointment for emergency treatment. Different studies showed that flare-ups represent a multifactorial phenomenon including mechanical, chemical and microbial factors. In addition, a correlation was found between flare-up and age, gender, tooth type, presence of preoperative pain, tooth condition before treatment, irrigation techniques, number of visits as well as intracanal medication. Moreover, some medicine intake was proved to be efficient in controlling this postoperative pain. However, a clear procedure to avoid its occurrence is yet to be established. In this review, we summarize knowledge about the etiology of flare-up and its related factors. This could be effective in helping dentists to adapt some strategies to prevent it.

Effect of a 980-nm diode laser on post-operative pain after endodontic treatment in teeth with apical periodontitis: a randomized clinical trial

BACKGROUND

This study aimed to assess the effect of a 980-nm diode laser following chemomechanical root canal preparation on the severity of post-operative pain (PP) after root canal treatment (RCT).

METHODS

This study included asymptomatic, single-rooted teeth with a periapical index (PAI) score of 3 or 4. All the patients received RCT, including dressing with calcium hydroxide (Ca(OH)₂), during two visits. The patients were randomly divided into two groups (n:30): a control group, in which the final irrigation was performed using 5 ml of 2.5% sodium hypochlorite (NaOCI), followed by 5 ml of 17% and ethylenediaminetetraacetic acid (EDTA) and 5 ml of distilled water, and a laser group, in which the root canals were irradiated using a 980-nm diode laser after the final irrigation at both visits. The pain levels after both visits were evaluated using a visual analogue scale (VAS) after 8 h, 24 h, 48 h and 7 d. In addition, the time intervals to medication intake were recorded. The collected data were statistically analysed using the chi-square and Mann-Whitney U test (p < 0.05).

RESULTS

The average pain level in the control group 24 h after the first visit was significantly higher than that in the laser group (p < 0.05). The average pain level 24 h and 48 h after the second visit was significantly higher in the control group (p < 0.05). The levels of PP 24 h after the first visit were higher than those after the second visit only in the control group (p < 0.05). After the first visit, analgesic use in the control group was significantly higher after 8 h (40%) and 24 h (23%) as compared with that in the laser group (p < 0.05).

CONCLUSIONS

Root canal irradiation with a diode laser may reduce PP after RCT in single-rooted teeth with a PAI score of 3 or 4.

TRIAL REGISTRATION

Effect of the Diode Laser on Post-operative Pain After Endodontic Treatment in Teeth with Apical Periodontitis: NCT04486196. Registered 24 July 2020-Retrospectively registered, http://clinicaltrials.gov/ct2/show/NCT04486196.

Postoperative pain in endodontic retreatment of one visit versus multiple visits: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The aim of this systematic review and meta-analysis (SRM) was to assess the postoperative pain (PP) after non-surgical endodontic retreatment (NSER) in a one visit compared to multiple visits. The PICO question used was "Does NSER in patients with unsatisfactory endodontic treatment in a one-visit visit have a similar PP to that of NSER in multiple visits?"

MATERIALS AND METHODS

This systematic review followed PRISMA and was registered in PROSPERO (CRD42019136700). Searches were performed in the PubMed/MEDLINE, Scopus, and the Cochrane Library databases for articles published until September 2020. The eligible criteria were randomized clinical trials (RCTs). The meta-analysis was based on the Mantel-Haenszel. The PP after the retreatment was analyzed using a dichotomous outcome, measured according to risk ratio (RR) when p < 0.05. The Cochrane scale was used to assess risk of bias, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the quality of evidence.

RESULTS

Four studies were included. In general analysis without considering intensity, one-visit NSER presented lower PP than the multiple visits only for 1 and 30 days [(RR = 0.67; CI: 0.48 to 0.93; p = 0.02), and (RR = 0.09; CI: 0.01 to 0.66; p = 0.02)], respectively. Regarding sub-analysis considering the intensity, one visit present lower mild PP when compared with multiple visits [(RR = 0.54; CI: 0.30, 0.96; p = 0.04); (RR = 0.33; CI: 0.12, 0.88; p = 0.03); and (RR = 0.12; CI: 0.02, 0.86; p = 0.03)], respectively. However, sub-analysis for moderate and severe PP showed no significant difference, independently of period evaluated (p > 0.05). Regarding the risk of bias analysis, a low risk was observed for most domains, except allocation that was considered unclear, while the certainty of evidence for each analysis was considered low.

CONCLUSION

Within the limitations of study, the one and multiple visit can be considered adequate, because both present a similar occurrence of PP, except for mild pain. However, due to the low number of studies, further well conducted and standardized RCTs are needed to reassess these results.

CLINICAL RELEVANCE

Both therapies of endodontic retreatment can be considered in clinical practice. Therefore, the endodontist must consider the patient's individual characteristics and experience to consider the best treatment approach.

Systematic Review on the Role of Lasers in Endodontic Therapy: Valuable Adjunct Treatment?

(1) Background: Adjunctive instruments, such as lasers have been investigated to address the risk of failure of endodontic therapy due to the complexity of the root canal system. Lasers have been used therapeutically, in direct irradiation of the root canals or adjunct to irrigants placed into the canals, in combination with a photosensitizer (antimicrobial photodynamic therapy) and in pain management (photobiomodulation). The purpose of this systematic review was to evaluate the evidence in clinical use within these three areas of therapy. (2) Methods: PubMed, Cochrane and Scopus search engines were used to identify human clinical trials regarding the use of lasers in endodontic therapy. (3) Results: After applying the keywords and additional filters, inclusion and exclusion criteria, the initial number of 1486 articles was reduced to 17. It was revealed that almost all studies (14/17) presented a statistically significant improved outcome in laser-assisted endodontic therapy, with the remaining three not showing any adverse effects. (4) Conclusions: The use of laser photonic energy of appropriate delivered parameters can be proposed as useful adjunctive when considering optimal treatment modalities in orthograde endodontics. Additionally, a tendency of research towards pain modulation in this field is developing.

Postoperative pain and antibacterial effect of 980 nm diode laser versus conventional endodontic treatment in necrotic teeth with chronic periapical lesions: A randomized control trial

Background: Many challenges encounter the endodontist, especially when dealing with necrotic teeth with chronic periapical lesions. Postoperative pain may be induced following conventional endodontic therapy and total eradication of the bacteria is almost unachievable even with recently available techniques. In recent years, diode laser usage in the endodontic field has gained acceptance. Thus, this study aimed to investigate the ability of the diode laser (DL) to decrease postoperative pain and achieve root canal sterility. Methods: 56 patients with anterior teeth with chronic periapical lesions in upper anterior teeth were randomly divided into two groups (n = 28). All patients were treated with two visits of conventional root canal treatment with ProTaper Universal. The DL group: root canals were irradiated with 200 µm fiber optic at both visits; the control group (Endo): the DL fiber was placed in root canal with no activation. Bacterial samples were collected from all the cases at each step of the treatment. Pain levels were evaluated using a numerical rating scale preoperatively, and after 6, 12, 24, 48 hours and 7 days. Bacterial count was used to detect both aerobic and anaerobic bacterial load.  Results: The qualitative pain scores revealed statistically significant lower pain levels in the DL group compared with the Endo group at all time intervals (P<0.001), except preoperatively where there was no significant difference. There was a statistically significant lower bacterial count for both aerobic and anaerobic bacteria in the DL group compared with the Endo group in both S3 samples (after laser application) and S4 samples (bacterial colonization) (P<0.001). Conclusion: The 980 nm diode laser may be a successful adjunct to conventional endodontic treatment of necrotic cases with chronic periapical lesions in terms of postoperative pain and root canal disinfection.   Trail registration: PACTR201511001275414 (date: 23 rd September 2015).