A clinical study on the effects of pulsed Nd:YAG laser irradiation at root canals immediately after pulpectomy and shaping

The influence of laser-activated irrigation on post-operative pain following root canal treatment: A systematic review

OBJECTIVES

Synthesise evidence on post-endodontic pain (PEP) in adult teeth undergoing primary root canal treatment with the adjunctive use of laser-activated irrigation (LAI) as compared with conventional needle irrigation (CNI) during the first post-operative week.

DATA

An electronic search was performed; no language constraints or restriction on the year of publication were applied.

SOURCES

Medline, Scopus, Cochrane and PubMed on 04 June 2023 STUDY SELECTION: Randomised clinical trials (RaCTs) that evaluated PEP after LAI of endodontic irrgants were included. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used. PEP was analysed at various time intervals until 1 week after treatment, related to the type of LAI used and the need for analgesia.

REULTS

Of the 793 articles identified through the electronic database search, 6 RaCTs were included. Qualitative review was favoured over meta-analysis due to substantial methodological heterogeneity between studies. Five studies were at high risk for bias determined by the Cochrane Risk-of-Bias 2 tool. Diode LAI demonstrated superior efficacy to needle irrigation in reducing pain 6-48 h post-treatment. The impact of LAI by photon-induced photoacoustic streaming (PIPS) was unclear and no difference was observed between PIPS and needle irrigation. However, PIPS mitigated PEP better than manual dynamic activation, sonic and ultrasonic activation. There was no difference in analgesia intake between LAI and needle irrigation groups.

CONCLUSIONS

LAI may help reduce PEP in the first 48 h. Methodological standardisation of future RaCTs on LAI would be beneficial in allowing a more accurate review with the possibility of quantitative synthesis.

CLINICAL SIGNIFICANCE

This unique synthesis used stringent criteria to reduce confounding factors and provided valuable evidence regarding PEP with different types of LAI. It helps clinicians choose an appropriate LAI technique as compared with CNI and predicts a time frame for reducing PEP.

Effect of Laser Therapy on Postoperative Pain and Endodontic Retreatment: A Systematic Review and Meta-Analysis

BACKGROUND

Root canal re-treatment (RCR) cases are considered some of the most challenging cases in the field of endodontics, as they are mostly associated with various iatrogenic errors such as ledge formation, incomplete biomechanical preparation, file separation, and incomplete obturation. These iatrogenic errors lead to defective niches within root canals that may act as reservoirs for various viable microorganisms. Such residual microbial niches may cause postoperative pain even after thorough debridement and reshaping the canals, ultimately leading to a poor prognosis for the tooth. Nowadays, prevention of postoperative pain in re-treatment cases and prognosis are effectively managed by photobiomodulation therapy (PBMT).

METHOD

Relevant studies in the English language published before November 2022 were identified using electronic databases like PubMed, SCOPUS, and EBSCO to conduct bibliographic research. This systematic review is based on 3 studies that were found eligible as per the inclusion and exclusion criteria. This systematic review is in accordance with PRISMA guidelines.

RESULTS

The systematic review indicated a positive impact by significantly decreasing postoperative pain in RCR cases when treated with PBMT. The variation was statistically significant at 24 hours (P = .0002), 48 hours (P = .03), and 72 hours (P = .02). The mean difference at 24 hours was 0.65 (95% CI, 0.32-0.99), at 48 hours was 0.46 (95% CI, 0.05-0.87), and at 72 hours was 0.40 (95% CI, 0.07-0.74). There was no statistical heterogenicity at 24 hours (P > .05), but a medium heterogenicity was observed at 48 hours and 72 hours.

PRACTICAL IMPLICATION

PBMT or low-level laser therapy has shown superior results as compared to the conventional pharmacologic approach in postoperative pain management in RCR cases.

Postoperative pain after single-visit root canal treatment or vital pulp therapy: A systematic review and meta-analysis

BACKGROUND

This systematic review aimed to investigate whether vital pulp therapy and root canal treatment (RCT) promote different postoperative pain.

STUDIES REVIEWED

The authors searched PubMed, Cochrane Library, Embase, and Latin American and Caribbean Health Sciences Literature databases for studies published through June 30, 2022. The authors included randomized clinical trials if they reported on the assessment of postoperative pain after direct pulp capping, partial pulpotomy, pulpotomy, or single-visit RCT. The authors assessed the frequency of no, mild, moderate, and severe postoperative pain. They conducted meta-analyses to compare postoperative pain after full pulpotomy (PULP) and RCT.

RESULTS

The qualitative synthesis included 57 studies, and the authors conducted meta-analysis of 3. PULP leads to more asymptomatic cases (relative risk [RR], 1.06; 95% CI, 1.01 to 1.11; P < .01; I2 = 67%) and to a lower occurrence of mild (RR, 0.89; 95% CI, 0.79 to 0.99; P < .04; I2 = 37%) and moderate (RR, 0.70; 95% CI, 0.51 to 0.95; P < .02; I2 = 57%) postoperative pain than RCT. The frequency of severe pain was very low for both vital pulp therapy and RCT. Moderate to severe postoperative pain was more common at 48 hours through 72 hours after RCT and up to 36 hours after PULP. Pain intensity after PULP was higher using calcium-enriched material compared with using mineral trioxide aggregate at 12, 18, and 36 hours (P < .001).

PRACTICAL IMPLICATIONS

PULP showed a significantly higher incidence of no pain and a lower incidence of mild and moderate pain than single-visit RCT. Clinical decisions for RCT or PULP should not be based on differences in postoperative pain. When analgesia is indicated, it probably should be limited to a short time after PULP.

Effect of low-level laser therapy on postoperative pain after single-visit root canal retreatment of mandibular molars: A randomized controlled clinical trial

AIM

To compare the effect of low-level laser therapy (LLLT) on postoperative pain after single-visit root canal retreatment on mandibular molars.

METHODOLOGY

This randomized controlled clinical trial included 36 patients referred to the Department of Endodontics, Islamic Azad University, Tehran, Iran. Healthy patients who required root canal retreatment on symptomatic first or second mandibular molars, with a PAI index score of 2 or 3, preoperative tooth and percussion pain of <56 mm on a 170-mm visual analogue scale (VAS) were included. After local anaesthesia using inferior alveolar nerve block followed by rubber dam isolation and access cavity preparation, the D RaCe retreatment system was used to remove the existing root filling material, and after canal negotiation and gaining patency, working length was determined with an apex locator. Further canal enlargement was carried out with size 35, 0.04 taper, and size 40, 0.04 taper RaCe rotary instruments and then canals were filled using laterally compacted gutta-percha points and AH Plus sealer. The patients were randomly assigned to treatment groups: In the LLLT group, a 980-nm diode laser set at 6.89 W/cm² energy density, 0.5 W power, and a tip diameter of 10 mm were activated from the buccal side on the mesial and distal root apices for 15 s. In the sham group, the laser handpiece was placed inside the patient's mouth at the same location, but the laser was not activated. Then patients were instructed to record their postoperative pain levels at 4, 8, 12 and 24 h and 2, 3 and 7 days after treatment on separate VAS scales. For data analysis, the independent sample t and the Mann-Whitney U tests were used. Nominal variables were analysed by using the chi-square test.

RESULTS

In the LLLT group, the most intense pain was reported 24 and 48 h post-treatment [mean (SD) = 0.22 (0.54) for both], whereas in the sham group, the most intense pain level was observed 4 h post-treatment [mean (SD) = 0.78 (0.80)]. At the 4-h interval, pain intensity was significantly lower in the LLLT group (p = .016).

CONCLUSIONS

Low-level laser therapy reduced postoperative pain after single-visit root canal retreatment of mandibular molars only four hours following the procedure.

Evaluation of postoperative pain/discomfort after intracanal use of Nd:YAG and diode lasers in patients with symptomatic irreversible pulpitis and asymptomatic necrotic pulps: a randomized control trial

OBJECTIVES

This study aimed to investigate the ability of the diode and Nd:YAG lasers to decrease postoperative pain/discomfort after intracanal application in vital and devital endodontic cases.

MATERIAL AND METHODS

One hundred two patients with symptomatic irreversible pulpitis and asymptomatic necrotic pulps were selected and randomly divided into three groups. After chemomechanical preparation, Nd:YAG and diode laser was applied to first and second groups for final treatment of the root canals. In the control group, no further disinfection protocol was performed upon traditional procedures. Then all the teeth were obturated in the same appointment. Pre- and postoperative pain were recorded using the VAS at 0, 12th, 24th, 48th, and 72nd hours following the treatment Kruskal-Wallis and Dunn test.

RESULTS

VAS scores were significantly the most at 12-h period compared with other time periods after treatment for all groups. There was no significant difference among Nd:YAG laser, diode laser, and control groups in non-vital cases (p > 0.05). In vital cases, Nd:YAG laser group represented significantly fewer scores compared with diode laser and control groups at 48-h period (p < 0.05).

CONCLUSIONS

The processes involving the use of Nd:YAG and diode lasers after chemomechanical preparation was found to be equivalent in terms of postoperative pain intensity after completion of treatment in one session both in vital or non-vital cases except in vital cases in Nd:YAG group at 48 h.

CLINICAL RELEVANCE

Adjunct clinical use of Nd:YAG or diode lasers to traditional chemomechanical preparation did not cause any improvement or deterioration on postoperative discomfort and pain in patients with symptomatic irreversible pulpitis and asymptomatic necrotic pulps.

Effects of pulsed Nd:YAG laser irradiation on smear layer at the apical stop and apical leakage after obturation

AIM

This study evaluated the removal of smear layer at the apical stop by pulsed Nd:YAG laser irradiation with or without black ink, and the degree of apical leakage after obturation in vitro.

METHODOLOGY

Sixty extracted human single-rooted teeth were used in this study. The teeth were instrumented up to a size 40 K-file, and then divided into three groups of 20 teeth each: group 1 was unlased as a control group; group 2 was treated with a laser; group 3 was treated with a laser and black ink. The laser was operated at 2 W and 20 pp for 2 s, and irradiation was performed twice with a 30-s interval. In each group, 10 teeth for the leakage study were obturated and immersed in rhodamine B solution for 48 h at 37 degrees C, and the others were used for evaluation of remaining smear layer. All teeth were bisected longitudinally and observed by stereoscopy or scanning electron microscopy.

RESULTS

The smear layer in the laser-treated groups almost melted or evaporated, and was removed significantly compared with the control group (P < 0.05). Leakage was observed in 60% of samples in group 1 and in 20% of samples in group 2. No leakage was observed in group 3, which was significantly different from the control (P < 0.05).

CONCLUSIONS

These results suggest that pulsed Nd:YAG laser irradiation with black ink increases the removal of smear layer compared with that without black ink, and reduces apical leakage after obturation significantly.

Study on removal effects of filling materials and broken files from root canals using pulsed Nd:YAG laser

OBJECTIVES

The aims of this study were to investigate the capability of removing the filling materials or broken files from root canals with pulsed Nd:YAG laser irradiation at three parameters, and to evaluate the temperature rises on root surfaces and morphological changes of root canal walls in vitro.

SUMMARY BACKGROUND DATA

There has been no report on removing the filling materials and broken instruments from root canals with laser irradiation.

MATERIALS AND METHODS

Thirty-six extracted human incisors were divided into two groups of 18 each. Eighteen root canals were shaped and obturated with gutta-percha and root canal sealer. In another 18 specimens, 3-mm long fractures of files were performed intentionally during root canal preparation. A pulsed Nd:YAG laser irradiation was performed repeatedly at three parameters of 1, 2, and 3 W to remove the filling materials or file fragments. Temperature rises on root surfaces during laser irradiation were measured by thermography, and the remaining of obturated materials and morphological changes of root canal walls were evaluated by stereoscopy and scanning electron microscopy.

RESULTS

In more than 70% of the teeth, the obturated materials were completely removed by laser, and in more than 55% of the teeth, the broken files were successfully removed. Temperature rises ranging from 17 degrees C to 27 degrees C were measured from 6 to 11 repeated times.

CONCLUSION

These results demonstrated that a pulsed Nd:YAG laser irradiation has the capability of removing the obturated materials in root canals and is useful for removing the broken files in same if the counter-measure reducing the temperature rise is performed.