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.

Mechanical activation with Easy Clean device enhanced organic tissue removal from simulated internal root resorption in a laboratory evaluation.

BACKGROUND: Considering the irregular shape of the root canal, removing inflamed pulp and granulation tissue completely from internal resorption cavities during chemomechanical preparation can be challenging. This study aimed to evaluate the effectiveness of passive ultrasonic irrigation (PUI) compared to mechanical activation with Easy Clean in the removal of organic tissue from simulated areas of internal root resorption. METHODS: The root canals of 72 extracted single-rooted teeth with oval canals were instrumented with Reciproc R25 instruments. After root canal preparations, the specimens were split longitudinally, and semicircular cavities were prepared using a round bur on each half of the roots. Samples obtained from bovine muscle tissue were weighed and adapted into semicircular cavities. The roots were reassembled and joined, and the teeth were divided into six groups (n = 12) according to the irrigation protocol: Sodium hypochlorite (NaOCl) without activation; NaOCl + PUI; NaOCl + Easy Clean; distilled water without activation; distilled water + PUI; and distilled water + Easy Clean. After irrigation protocols, the teeth were disassembled, and the remaining organic tissue was weighed. Data were analyzed by two-way ANOVA and Tukey's post hoc test (p < 0.05). RESULTS: None of the experimental protocols totally removed the bovine tissue from simulated cavities. Tissue weight reduction was significantly affected by the activation method (p < 0.05) and by irrigation solution (p < 0.05). Groups with NaOCl irrigation presented higher tissue weight loss when compared to distilled water, for all irrigation methods (p < 0.05). The use of Easy Clean resulted in the greatest tissue weight loss (42.0%-Distilled water/45.5%- NaOCl) compared to those of PUI (33.3%-Distilled water/37.7%- NaOCl) and no activation (33.4%-Distilled water/38.8%- NaOCl) (p < 0.05). However, no differences were observed between PUI and no activation groups (p > 0.05). CONCLUSIONS: Mechanical activation with Easy Clean enhanced organic tissue removal from simulated internal resorption more effectively than PUI. Easy Clean for agitation of the irrigating solution is effective in removing simulated organic tissues from artificial internal resorption cavities, being an alternative to the use of PUI.

Effect of low-level laser therapy on postoperative endodontic pain: An updated systematic review.

OBJECTIVE: To evaluate the influence of low-level laser therapy (LLLT) on postoperative pain after endodontic treatment. METHODS: The PICOS strategy was used to identify randomized clinical trials comparing low-level laser therapy and mock laser therapy to manage postoperative pain after endodontic treatment, retreatment, and endodontic surgery. An electronic search was performed in MEDLINE through PubMed, Web of Science, LILACS, Scopus and Cochrane Library, OpenGrey and Google Scholar. Quality assessment was performed using the Cochrane Collaboration's tool for assessing the risk of bias. The quality of evidence was rated on the basis of the GRADE approach. RESULTS: Twelve studies were included in the qualitative synthesis. Within the 12 studies, 7 articles were classified as "low risk of bias," 4 studies were considered "unclear risk of bias" and 1 study was considered "high risk of bias." Six studies evaluated the postoperative pain after primary root canal treatment, two studies after root canal retreatment and four after periapical surgery. Most of the studies reported significantly less postoperative pain after LLLT in different time periods; two studies found no differences. The certainty of evidence was classified as low and very low to treatment / retreatment and endodontic surgery, respectively. CONCLUSIONS: Based on the limited quality evidence, most of the included studies reported significantly less postoperative pain after LLLT. However, the lack of standardization in laser parameters, use of medications and the certainty of evidence classified as low and very low indicate the need for further studies.

Effect of intracanal cryotherapy application on postoperative endodontic pain: a systematic review and metaanalysis.

OBJECTIVES: To assess the influence of intracanal cryotherapy application on postoperative pain after endodontic treatment. MATERIALS AND METHODS: A systematic review (SR) was conducted in seven databases. Articles that were published up to 04 February 2020 were included and randomized clinical trials that used a cold saline solution for final irrigation to manage postoperative endodontic pain were compared with those that used a saline solution at room temperature. Metaanalysis was performed to assess postoperative pain after 6, 24, 48, and 72 h using a random effects model, a confidence interval of 95%, and heterogeneity tested by the I2 index. The certainty of evidence was rated using GRADE. RESULTS: Qualitative and quantitative analysis included eight and six studies, respectively. Individuals treated with cryotherapy presented lower means of postendodontic pain than the controls, 6 and 24 h after endodontic treatment (MD - 1.30 [- 2.32, - 0.28] p = 0.01 and SMD - 0.68 [ - 1.21, - 0.16] p = 0.01, respectively, with very low certainty of evidence). After 48 and 72 h, both groups demonstrated similar means of postendodontic pain (MD - 0.06 [- 0.18, 0.07] p = 0.38 and SMD - 0.54 [- 1.18, - 0.11] p = 0.10, with high and low certainty of evidence, respectively). CONCLUSIONS: Based on the limited quality evidence, intracanal cryotherapy application reduced postoperative endodontic pain after 6 and 24 h. New clinical trials are needed to support the result of this review. CLINICAL SIGNIFICANCE: This SR provides information about the use of intracanal cryotherapy in clinical practice, guides clinicians to make evidence-based decisions and suggests recommendations for further high-quality studies.

Evaluation of ceramic flexural strength of a cobalt-chromium alloy subjected to airborne particle abrasion and tungsten inert gas welding

Aim: The aim of this study was to evaluate the influence of tungsten inert gas (TIG) welding and airborne particle abrasion using aluminum oxide particles on the flexural strength of a joint between ceramic and cobalt-chromium alloys. Methods: The specimens were cast and welded using TIG, then divided into 6 groups (n = 10) and subjected to blasting with 250 µm, 100 µm, and 50 µm aluminum oxide particles. Ceramic systems were applied to the central part of all specimens. A three-point bending test using a velocity of 0.5 mm/m was performed on the specimens to measure flexural strength. Data were analyzed using two-way analysis of variance and Tukey's test. Results: TIG welding demonstrated the lowest resistance compared with the non-welded groups. Airborne particle abrasion using 250 µm aluminum oxide particles demonstrated greater resistance in the welded groups (p < 0.05). Mixed faults were found in all specimens. Conclusion: TIG welding decreased the bond strength, and the particle size of aluminum oxide did not affect the metal-ceramic bond in groups without TIG welding