Effect of Er:YAG laser irradiation using SWEEPS and PIPS technique on dye penetration depth after root canal preparation

BackgroundThis study aimed to investigate the penetration depth of two different dyes after root canal preparation using PIPS and SWEEPS methods.Materials and methodsA total of 60 single-rooted human teeth which were extracted for periodontal reasons were collected and stored in the sterile saline until using in the study. The crowns of the teeth were cut such that the remaining piece was 12 mm long. The root canals were prepared. Teeth were divided randomly into two initial groups (n = 30): indocyanine green solution (ICG) and methylene blue solution. Then, these teeth were divided into final subgroups (n = 10): Er:YAG laser irradiation with PIPS(photon-induced photoacoustic streaming) technique, Er:YAG laser irradiation with SWEEPS(shock-wave enhanced emission photoacoustic streaming) technique, and no irradiation. The penetration depth measurements were done by the stereo microscope in three zones of each specimen.ResultsThe difference between ICG in the control group and PIPS and SWEEPS in the coronal area was not significant. In the middle section the difference between PIPS and the control group was marginally insignificant (P = 0.053). In the methylene blue group, PIPS had significantly higher penetration depth in the apical area compared to the control group (P = 0.004). In the middle section, both PIPS and SWEEPS showed significantly higher penetration than the control group.ConclusionAccording to the results of this study, the laser has the potential to increase the penetration of methylene blue. Root canal preparation with the PIPS technique can increase the dye penetration. However, the SWEEPS technique and the conventional method have a similar outcome in terms of dye penetration.     

Dentinal tubule penetration and root canal cleanliness following ultrasonic activation of intracanal‐heated sodium hypochlorite

This study investigated the effect of ultrasonic activation of intracanal‐heated sodium hypochlorite (NaOCl) on its dentinal tubular penetration and root canal cleanliness in vitro. In experiment 1, mandibular premolars were randomly allocated to three groups (n = 8): group A, ultrasonic activation; group B, ultrasonic activation of intracanal‐heated NaOCl and group C, syringe‐and‐needle irrigation. Penetration of the fluorescent‐labelled NaOCl was investigated using light microscopy. In experiment 2, mandibular premolars were randomly allocated to group B or C (n = 10), for histological analysis of the remaining pulp tissue and debris. Data were statistically analysed using Kruskal–Wallis and Mann–Whitney tests (P = 0.05). The highest penetration of NaOCl was observed in group B, followed by group A (P < 0.05). Group B showed significantly less amount of debris than group C (P < 0.05). Dentinal tubule penetration of NaOCl and root canal cleanliness were significantly improved by ultrasonic activation of intracanal‐heated NaOCl.     

Factors affecting irrigant extrusion during root canal irrigation: a systematic review

The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted in Cochrane Library, LILACS, PubMed, SciELO, Scopus and Web of Knowledge using a combination of the terms ‘irrigant’, ‘rinse’, ‘extrusion’, ‘injection’, ‘complication’, ‘accident’, ‘iatrogenic’, ‘root canal’, ‘tooth’ and ‘endodontic’. Additional studies were identified by hand‐searching of six endodontic journals and the relevant chapters of four endodontic textbooks, resulting in a total of 460 titles. No language restriction was imposed. After applying screening and strict eligibility criteria by two independent reviewers, 40 case reports and 10 ex vivo studies were included in the review. A lack of clinical studies focusing on irrigant extrusion during root canal irrigation was evident. The reviewed case reports focused mainly on the clinical manifestations and management of the accidents and did not provide adequate details on the possible factors that may influence irrigant extrusion. The data from the included ex vivo studies were inconclusive due to major methodological limitations, such as not simulating the presence of periapical tissues and not assessing the validity of irrigant detection methods. The extensive variability in the protocols employed hindered quantitative synthesis. The choice of factors investigated in ex vivo studies seems not to have been driven by the available clinical evidence. These issues need to be addressed in future studies.     

Concentration-dependent Effect of Sodium Hypochlorite on Stem Cells of Apical Papilla Survival and Differentiation

Introduction

Intracanal disinfection is a crucial step in regenerative endodontic procedures. Most published cases suggest the use of sodium hypochlorite (NaOCl) as the primary irrigant. However, the effect of clinically used concentrations of NaOCl on the survival and differentiation of stem cells is largely unknown. In this study, we tested the effect of various concentrations of NaOCl on the stem cells of the apical papilla (SCAPs) survival and dentin sialophosphoprotein (DSPP) expression.

Methods

Standardized root canals were created in extracted human teeth and irrigated with NaOCl (0.5%, 1.5%, 3%, or 6%) followed by 17% EDTA or sterile saline. SCAPs in a hyaluronic acid–based scaffold were seeded into the canals and cultured for 7 days. Next, viable cells were quantified using a luminescence assay, and DSPP expression was evaluated using quantitative real-time polymerase chain reaction.

Results

There was a significant reduction in survival and DSPP expression in the group treated with 6% NaOCl compared with the untreated control group. Comparable survival was observed in the groups treated with the lower concentrations of NaOCl, but greater DSPP expression was observed in the 1.5% NaOCl group. In addition, 17% EDTA resulted in increased survival and DSPP expression partially reversing the deleterious effects of NaOCl.

Conclusions

Collectively, the results suggest that dentin conditioning with high concentrations of NaOCl has a profound negative effect on the survival and differentiation of SCAPs. However, this effect can be prevented with the use of 1.5% NaOCl followed by 17% EDTA. The inclusion of this irrigation regimen might be beneficial in regenerative endodontic procedures.     

Osmolarity and root canal antiseptics

Antiseptics used in endodontics for disinfection purposes include root canal dressings and irrigants. Osmotic shock is known to cause the alteration of microbial cell viability and might have a role in the mechanism of action of root canal antiseptics. The aim of this review was to determine the role of osmolarity on the performance of antiseptics in root canal treatment. A literature search using the Medline electronic database was conducted up to 30 May 2013 using the following search terms and combinations: ‘osmolarity AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmolality AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmotic AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmosis AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; sodium chloride AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm’. Publications were included if the effects of osmolarity on the clinical performance of antiseptics in root canal treatment were stated, if preparations with different osmolarities values were compared and if they were published in English. A hand search of articles published online, ‘in press’ and ‘early view’, and in the reference list of the included papers was carried out following the same criteria. A total of 3274 publications were identified using the database, and three were included in the review. The evidence available in endodontics suggests a possible role for hyperosmotic root canal medicaments as disinfectants, and that there is no influence of osmolarity on the tissue dissolution capacity of sodium hypochlorite. There are insufficient data to obtain a sound conclusion regarding the role of hypo‐osmosis in root canal disinfection, or osmosis in any further desirable ability.     

冲洗液对环氧树脂基根管糊剂材料聚合影响的体外研究

目的：体外研究不同根管冲洗液润湿环境下环氧树脂基根管糊剂材料的聚合转化。方法：在直径2 cm的圆形聚酯薄片上制备AH Plus树脂薄膜,置于不同冲洗液润湿环境的50 mL离心管内聚合。利用傅里叶变换红外光谱仪检测树脂聚合反应前和反应24 h后的聚合转化率。结果：除对照组与95％乙醇之间、两实验组H2O和17％EDTA之间的差异无统计学意义外,两两之间的差异均有统计学意义（P＜0．05）。结论：95％乙醇对AH Plus聚合无影响;而H2O、17％EDTA、2．5％NaOCl显著降低了AH Plus的聚合度,其中2．5％NaOCl降低作用影响最大,H2O和17％EDTA的影响作用其次且相同。临床上应谨慎选择最终根管冲洗液,以避免牙本质残留冲洗液对AH Plus材料的聚合转化的影响。     

不同冲洗剂用于根管超声波清洗的扫描电镜观察

目的比较不同冲洗剂用于超声根管冲洗的清理效果。方法24颗离体单根管牙截冠后随机分为3组采用冠向下法进行根管预备后,使用不同的冲洗液对各组进行超声根管冲洗,A组用2％醋酸氯已定溶液（CHX）,B组用2．5％次氯酸钠溶液（NaClO）,C组用蒸馏水。最后,将牙体沿颊舌向纵劈,扫描电镜观察各组样本在根颈、中、尖1／3牙本质碎屑和玷污层的去除情况,统计学分析比较各组根管清洁的差异。结果各组在根颈部、中部和尖部残留碎屑量差异无统计学意义（P〉0．05）。但各组根颈部、中部和尖部去除玷污层的能力差异有统计学意义（P〈0．05）,两两比较得出A、B组优于C组,差异有统计学意义（P〈0.05）,A、B组相比差异有统计学意义（P〈0．05）。结论超声冲洗是清除碎屑的有效技术。2．5％次氯酸钠和2％氯已定均可去除玷污层,次氯酸钠超声根管冲洗效果优于氯已定。     

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??Objective    To evaluate and compare the amount of debris and irrigant extrusion quantitatively by using rotary nickel-titanium ??Ni-Ti?? instrument and sonic handpiece in root canal preparation. Methods    Forty freshly extracted human teeth were selected??which were with single canals??having similar canal length and curvature??due to orthodontics therapy and periodontitis in Department of Oral and Maxillofacial Surgery of China Medical University Stomatology Hospital during October 2012 to January 2014. They were separated into two groups based on Ni-Ti instruments ProTaper and sonic handpiece and mounted in a debris collection apparatus. After each instrument change??1 mL of NaClO was used as the irrigant and the amount of irrigant extruded was measured by EP tube. The EP tube was weighed using an electronic microbalance to determine its weight. After drying in an incubator for five days??the EP tube was weighed again. Compare the amount of debris and irrigant extrusion quantitatively. Results    The median of the amount of irrigant??in the group of ProTaper it was 116.24 mg??in the group of sonic handpiece it was 13.76 mg. The rotary Ni-Ti instrumentation techniques extruded significantly more irrigant than sonic handpiece??P < 0.05??. The median of the amount of debris??in the group of ProTaper it was 4.87 mg??in the group of sonic handpiece it was 0.63 mg. The rotary Ni-Ti instrumentation techniques extruded significantly more debris than sonic handpiece??P < 0.05??. Conclusion    The sonic handpiece extrudes significantly less irrigant and debris than the rotary Ni-Ti instrumentation techniques. It has a good clinical application prospects.     

声波手机与机用镍钛器械根管预备过程中根尖冲洗液及碎屑溢出比较研究

评价机用镍钛器械与声波手机根管预备过程中冲洗液及碎屑溢出根尖情况。 方法    选取2012年10月至2014年1月在中国医科大学附属口腔医院口腔外科门诊因正畸治疗需要或牙周炎症拔除的单根管离体牙（长度与弯曲度相近）40颗作为研究样本,随机分为ProTaper组（使用机用ProTaper镍钛锉进行根管预备）和Sonic handpiece组（使用MM1500声波手机及其配套的Rispisonic和Shaper锉进行根管预备）,并将离体牙安装到碎屑及液体收集装置。在根管预备过程中每换用一号器械时,用1 mL次氯酸钠溶液进行根管冲洗,用EP管收集根尖溢出冲洗液及碎屑,称重;恒温箱内干燥5 d后再次称重。比较两组根尖冲洗液及碎屑溢出情况。 结果    根尖冲洗液溢出量的中位数：ProTaper组为116.24 mg,Sonic handpiece组为13.76 mg,两组差异有统计学意义（P < 0.05）。根尖碎屑溢出量的中位数：ProTaper组为4.87 mg,Sonic handpiece组为0.63 mg,两组差异有统计学意义（P < 0.05）。结论    使用声波手机在根管预备时产生的根尖冲洗液及碎屑溢出均明显少于使用机用镍钛器械;声波手机具有较好的临床应用前景。