Effect of passive ultrasonic irrigation on hard tissue debris removal: a systematic review and meta-analysis

Can the addition of surfactants to NaOCl irrigation impact on the percentage of voids of root canal filling?

This study evaluated the impact of canal irrigation using surfactants associated to NaOCl on the percentage of voids of root canal filling through micro-computed tomographic (micro-CT) analysis. 27 mandibular mesial roots with Vertucci type II canal configuration with isthmus were selected and scanned in a micro-CT device. The specimens were assigned to three groups (n = 9), according to the irrigation solution during instrumentation: 2.5% NaOCl without additives (control), 2.5% NaOCl with 0.1% Benzalkonium Chloride and 2.5% NaOCl with 0.1% Tween 80. After obturation, the specimens were rescanned, and the percentage of voids were calculated. Data were analysed using one-way ANOVA with a significance level of 5%. The percentage of voids were similar among the groups (p > 0.05). None of the specimens showed completely voids-free areas. The addition of surfactants to NaOCl irrigation did not improve the quality of root canal filling of mandibular mesial root canals.

Impact of passive ultrasonic irrigation on the outcome of non-surgical root canal treatment: a systematic review and meta-analysis of randomized clinical trials

OBJECTIVE

This systematic review aimed to assess the impact of Passive Ultrasonic Irrigation on the periapical healing rate of primary root canal treatment compared to conventional syringe irrigation.

METHODS

Registered a priori in the PROSPERO database, this review was conducted by two independent reviewers who performed an electronic search up to December 2023. The search included databases such as MEDLINE (PubMed), Scopus, Web of Science, Embase, LILACS, and the Cochrane Library, as well as grey literature. We included randomized clinical trials (RCTs) that focused on patients undergoing primary root canal treatments. The study compared intervention groups using PUI with control groups that did not use activation techniques. Periapical healing was assessed over follow-up periods of at least six months, utilizing either periapical radiographs or cone-beam computed tomography. To synthesize the findings, a meta-analysis and trial sequence analysis were conducted, employing the Relative Risk as the measure of effect, with a 95% confidence interval. The GRADE approach was utilized to assess the certainty of the evidence.

RESULTS

The meta-analysis incorporated three RCTs, involving 474 patients (501 teeth). The analysis revealed that PUI led to a higher rate of periapical healing compared to CSI (Relative Risk: 1.10; 95% Confidence Interval: 1.01-1.21, I² = 0%), with moderate certainty of evidence.

CONCLUSIONS

Despite the limited number of high-quality RCTs, the findings showed a positive impact of PUI on periapical healing rates in primary root canal treatments, in comparison to CSI.

REGISTER

CRD42021290894.

Effect of preparation size on the removal of accumulated hard-tissue debris from the mesial root canal system of mandibular molars using SWEEPS technology

OBJECTIVES

This study assessed the influence of preparation size on the efficacy of shock wave-enhanced emission photoacoustic streaming (SWEEPS) and conventional irrigation (CI) on removal of accumulated hard tissue debris (AHTD) from isthmus-containing mandibular molars using micro-computed tomographic analysis.

MATERIALS AND METHODS

Sixty extracted mandibular molars with two mesial canals connected by an isthmus were selected. Canals were shaped with Mtwo instruments (VDW, Munich, Germany) up to sizes 25/.06, 40/.04 or 40/.06 (n = 20), and specimens were distributed into 2 final irrigation groups (n = 10): SWEEPS and CI. Roots were scanned at a resolution of 10.5 µm before and after preparation and final irrigation. Data sets were co-registered, and the percentage reduction of AHTD calculated for each specimen was statistically compared using analysis of variance with a of 5% significance level.

RESULTS

The preparation size did not significantly influence the percentage reduction of AHTD (p < 0.05), whereas the final irrigation technique had a significant effect on debris removal (p < 0.05). A significant reduction of AHTD was achieved after final irrigation in all groups (p < 0.05); however, SWEEPS was associated with a significantly greater percentage reduction of debris than CI (p < 0.05). None of the specimens presented a completely clean isthmus.

CONCLUSIONS

Removal of AHTD was not significantly affected by the preparation size. SWEEPS was associated with significantly less debris than CI.

CLINICAL RELEVANCE

SWEEPS performed significantly better than CI regarding the removal of AHTD from isthmus-containing mandibular molars irrespective of the preparation size.

Does ultrasonic activation of irrigation during endodontic therapy improve the clinical and microbiological effects?

Data sources A comprehensive collection of databases were searched from inception to August 2020, such as Cochrane, MEDLINE, Scopus and Web of science. Also, references and citations of retrieved records, conference proceedings and leading journals were searched.Study selection All randomised clinical trials on root-canal-treated adult permanent teeth that compared the outcomes of ultrasonically activated irrigation (UAI) to syringe irrigation (SI) were eligible. The outcomes considered were post-operative pain, pain intensity, periapical healing after 12 months, the incidence of microbial presence, microbial quantification, lipopolysaccharides (LPS) quantification and lipoteichoic acid quantification. Studies with insufficient data for risk of bias assessment or other outcomes were excluded.Data extraction and synthesis The two independent reviewers did the screening process in title, abstract and full-text assessment steps. Also, the data extraction process and risk of bias assessment were done by two independent reviewers. Any disagreement was resolved by consensus or the opinion of a third reviewer. Any missing information was filled in by contacting the authors. The Cochrane risk-of-bias tool for randomised trials was used to assess the risk of bias. The following domains were evaluated for risk of bias: randomisation process, deviation from the intended interventions, missing outcome data, outcome measurement and the selection of the reported results. If all domains were rated as 'low risk', judgements would be rated as 'low risk', otherwise, 'high risk'. The risk ratios and mean risk difference with 95% confidence interval (CI) were used as measure effect. The random effects model was used to combine the effects. The heterogeneity is measured by I² test (I² test >50% and p <0.1 considered as substantial heterogeneity). The level of certainty of evidence for clinically important outcomes was determined using the guidelines of Grading of Recommendations Assessment, Development and Evaluation working group.Results Four studies entered the meta-analysis stage based on pain outcomes. The overall risk of bias for three of them was assessed as high. All of them had examined pain incidence before 24 hours but only two studies have examined the occurrence of pain in the period of 24-72 hours and after 72 hours to 7 days. Considerable heterogeny was among the incidence of pain <24 hours between studies (I²= 83%). Therefore, the incidence of pain in two sub-groups of vital and non-vital pulp has been investigated. In the non-vital pulps, the incidence of pain by UAI was half of the incidence of SI pain (relative risk= 0.50; 95% CI 0.35-0.71; I2 = 0%; 308 teeth). But no significant difference was seen in vital pulps. Also, there was no significant difference in the occurrence of pain after 72 hours between the two methods. Two studies assessed the intensity of pain in three periods: <24 hours, 72-24 hours, more than 72 hours and less than 7 days. The combined results based on vital and non-vital groups resulted in no significant difference in any period. Pooled data of pain outcomes were assessed with very low or low confidence of evidence.Five studies with microbiology-related outcomes entered the final analysis stage. The overall risk of bias for two of them was high. Three studies evaluated the effect of the irrigation method on microbial presence as an outcome. High heterogeneity was among the results of the studies (I²= 72%). However, with and without subgroup analysis, meta-analysis results showed no significant difference between these two methods. A lower microbial count was found with UAI than SI in a meta-analysis of four studies (standardised mean difference-pooled - 0.40; 95% CI [-0.78, -0.02]; I2 = 0%; 126 teeth). Two studies measured LPs. The meta-analysis showed lower values of LPS with UAI compared to SI (34, 37) (mean difference pooled - 0.06; 95% CI [-0.11, -0.01]; 61 root canals; I² = 29%). One study measured lipoteichoic acid and found no significant difference between the irrigation methods.Three studies with treatment-success-related outcomes entered the meta-analysis stage with an overall high risk of bias. Two studies' pooled data revealed no significant difference between the irrigation methods regarding treatment failure. One study assessed periapical-lesion volume after treatment and found no significant difference between the irrigation methods.Conclusions According to limited data, UAI may reduce the risk of post-operative pain during the first 24 hours and reduce microbial counts, particularly cultivable germs in cases of apical periodontitis. However, most meta-analyses are conducted on a small number of studies and have an overall 'very low' to 'low' certainty of evidence; as a result, the evidence is deemed insufficient to either support or disprove UAI efficacy when compared to SI.