Does supplemental photodynamic therapy optimize the disinfection of bacteria and endotoxins in one-visit and two-visit root canal therapy? A randomized clinical trial

AimTo evaluate the effectiveness of supplemental photodynamic therapy (PDT) in optimizing the removal of bacteria and endotoxins from primarily infected root canals after one-visit and two-visit treatments.MethodologyTwenty-four primarily infected root canals with apical periodontitis were selected and randomly divided into one-visit (n = 12) and two-visit treatment groups (n = 12). Chemo-mechanical preparation (CMP) was performed by using the single-file reciprocating technique + 2.5% NaOCL and a final rinse with 17% EDTA. The photosensitizer agent (methylene blue 0.1 mg/mL) was applied to root canals for 60 s before application of laser with a potency of 60 mW and energy density of 129 J/cm² for 120 s after CMP in the one-visit treatment and after 14-day inter-appointment medication with Ca(OH)₂ + Saline solution (SSL) in the two-visit treatment. Samples were collected before and after root canal procedures. Endotoxins were quantified by chromogenic limulus amebocyte lysate assay. Culture techniques were used to determine bacterial colony-forming unit counts.ResultsBacteria and endotoxins were detected in 100% of the initial samples, with median values of 1.97 × 10⁵ CFU/mL and 24.983 EU/mL, respectively. The CMP using single-file reciprocating technique was effective in the reduction of bacteria and endotoxins (All, p < 0.05). The supplemental PDT was effective in reducing bacterial load in the one-visit (p < 0.05) but not in the two-visit treatment after use of Ca(OH)₂ medication for 14 days (p > 0.05). In the two-visit group, after 14 days of inter-appointment medication with Ca(OH)₂, a significant reduction in the median levels of endotoxins was found in comparison to CMP alone (from 1.041 to 0.094 EU/mL) (p < 0.05). Despite the type of treatment, the supplemental PDT was not effective against endotoxins (p > 0.05).ConclusionsThe photodynamic therapy optimized the disinfection of bacteria from root canals in one-visit but not for two visit treatment modality with the accomplishment of calcium hydroxide medication. Despite the type of treatment, the supplemental PDT was not effective against endotoxins.     

Longevity and Risk Factors of Post Restorations after up to 15 Years: A Practice-based Study

IntroductionThe aims of this multicenter, practice-based cohort study were to evaluate the success and survival of endodontically treated teeth with post restorations (ETT+Ps) and to analyze factors associated with the longevity of ETT+Ps.MethodsEight general dental practitioners each placed up to 27 ETT+Ps without any restriction to post materials or dimensions. Only incisors, canines, and premolars were included. At the last follow-up visit, ETT+Ps were considered as successful if the post and the initially placed definitive restoration were sufficient, whereas ETT+Ps were considered as survived if the post was still in function. Multilevel Cox proportional hazards models were used to evaluate the association between a range of predictors and time until no success and no survival.ResultsOverall, 195 endodontic posts in 195 patients were followed up for a mean (95% confidence interval) of 91 (81–101) months; the longest follow-up was 15 years. Of these, 122 ETT+Ps were considered successful (estimated success time = 110 [101–120] months), and 152 ETT+Ps survived [estimated survival time = 133 [124–141] months). Regarding the categories of success and survival, the annual failure rates were 6.0% and 3.3%, respectively. Recementation of old (telescopic) crowns after placing new posts was the only significant predictor for decreased time until failure for both success and survival analyses. By excluding recemented restorations, annual failure rates decreased to 3.5% and 2.1%, respectively.ConclusionsFor EET+Ps placed in a private practice setting, high success and survival rates were observed. If old (telescopic) crowns were recemented after new posts were placed, the high risk of subsequent failure should be considered and communicated with patients.     

Identification of Culturable and Nonculturable Microorganisms,Lipopolysaccharides, and Lipoteichoic Acids From Root Canals of Teeth With Endodontic Failure

AimTo elucidate the presence of apical periodontitis in the root canal of teeth with secondary/persistent infection, including composition of microbiota, levels of endotoxins and lipoteichoic acid (LTA), and clinical implications of these findings.MethodSamples were collected from root canals of 50 patients who needed endodontic retreatment and had radiographic evidence of apical periodontitis. Microorganisms were identified by using the culture technique and biochemical tests. Nested–polymerase chain reaction (nested-PCR) was used to identify 17 species of specific bacteria. Lipopolysaccharides (LPS) and LTAs were quantified by using, respectively, limulus amebocyte lysate and enzyme-linked immunosorbent assay tests.ResultsBacteria were detected in all samples by culture and molecular methods. A total of 154 gram-positive strains, of 188 strains isolated, were found in the root canals by culture. Enterococcus faecalis and Gemella morbillorum were the most prevalent species identified by the biochemical tests, whereas molecular analyses (nested-PCR) showed a high frequency of P. gingivalis, E. faecalis, and Fusobacterium nucleatum. LPS and LTA were detected in all samples, with mean values being 3.52 EU/mL and 597.83 pg/mL, respectively. Significant statistical correlations were found between levels of LTA and clinical features.ConclusionDespite the prevalence of gram-positives, the microbiota present in secondary/persistent infections showed a large variety of species. Within this diversity, associations were found between specific bacteria and clinical features. In addition, higher levels of LTA were statistically associated with larger periapical radiolucent areas, but no correlation between this feature and LPS was found.     

Properties of a modified quaternary ammonium silane formulation as a potential root canal irrigant in endodontics

ObjectivesEvaluate a new modified quaternary ammonium silane irrigant solution for its antimicrobial, cytotoxic and mechanical properties of dentine substrate.MethodsRoot canal preparation was performed using stainless steel K-files™ and F4 size protaper with irrigation protocols of 6% NaOCl + 2% CHX; 3.5% QIS; 2% QIS and sterile saline. Biofilms were prepared using E. faecalis adjusted and allowed to grow for 3 days, treated with irrigants, and allowed to grow for 7 days. AFM was performed and surface free energy calculated. MC3T3 cells were infected with endo irrigant treated E. faecalis biofilms. Raman spectroscopy of biofilms were performed after bacterial re-growth on root dentine and exposed to different irrigation protocols and collagen fibers analysed collagen fibers using TEM. Antimicrobial potency against E. faecalis biofilms and cytoxicity against 3T3 NIH cells were also. Resin penetration and MitoTracker green were also evaluated for sealer penetration and mitochondrial viability. Data were analysed using One-way ANOVA, principal component analysis and post-hoc Fisher’s least-significant difference.ResultsElastic moduli were maintained amongst control (5.5 ± 0.9) and 3.5% QIS (4.4 ± 1.1) specimens with surface free energy higher in QIS specimens. MC3T3 cells showed reduced viability in 6%NaOCl+2%CHX specimens compared to QIS specimens. DNA/purine were expressed in increased intensities in control and 6% NaOCl + 2% CHX specimens with bands around 480−490 cm⁻¹ reduced in QIS specimens. 3.5% QIS specimens showed intact collagen fibrillar network and predominantly dead bacterial cells in confocal microscopy. 3.5% QIS irrigant formed a thin crust-type surface layer with cytoplasmic extensions of 3T3NIH spread over root dentine. Experiments confirmed MitoTracker accumulation in 3.5% treated cells.SignificanceNovel QIS root canal irrigant achieved optimum antimicrobial protection inside the root canals facilitating a toxic effect against the Enterococcus faecalis biofilm. Root dentine substrates exhibited optimum mechanical properties and there was viability of fibroblastic mitochondria.     

牙体牙髓病学本科实习教学中医疗不良事件的原因分析与对策

目的分析口腔医学本科生在牙体牙髓病科实习期间出现医疗不良事件的原因,探讨减少和防止不良事件发生的对策。 方法收集2014年1月至2018年12月期间,通过中山大学附属口腔医院管理系统呈报的牙体牙髓病科实习生不良事件共计144例。采用回顾性分析方法对不良事件进行归纳总结,分析其发生原因,并针对性地制定改进和预防措施。使用SPSS 25.0软件对不良事件的类型及引起各类不良事件原因的数据进行分析,因各组数据不满足正态分布及方差齐性,故采用Mann-Whitney U检验。 结果口腔医学本科生在牙体牙髓病科临床实习教学过程中出现的不良事件,主要有职业暴露、医疗沟通事件与医疗处置事件三类,多属于Ⅲ级未造成后果事件和Ⅳ级隐患事件。其中,以职业暴露最为多见,五年共计63例,与医疗沟通事件（Z = 5.765,P<0.001）、医疗处置事件（Z = 4.163,P<0.001）相比,差异均有统计学意义。职业暴露主要由操作疏忽或不合规范引起,与防范意识不足（Z = 4.063,P<0.001）、患者因素（Z = 3.421,P<0.001）,以及科室教育不足（Z = 4.263,P<0.001）相比,差异具有统计学意义。导致医疗沟通事件发生的主要原因是医护态度,与收费标准（Z = 4.139,P<0.001）、患者不实期望（Z = 3.990,P<0.001）和不信任实习生（Z = 3.314,P<0.001）相比,差异具有统计学意义。导致医疗处置事件的原因有知识缺乏、操作不规范和带教指导不足,三者之间差异无统计学意义（P>0.05）。 结论通过制定各种预防及改进措施有助于减少口腔医学本科生在牙体牙髓实习教学中不良事件的发生,促进医患关系的和谐发展。     

翻转课堂在牙体牙髓病学临床前期实习中的应用

翻转课堂是一种新的教学模式,是医学教育改革的新方向。本文介绍了翻转课堂的起源、特点,在国内医学教育中应用的现状,现阶段牙体牙髓病学临床前期实习教学中存在的问题。探讨了如何在牙体牙髓病学临床前期实习中构建翻转课堂教学模式,以及应用这一新的教学模式所面临的挑战。     

牙体牙髓病科患者特点的2次调查结果比较

目的了解江苏省口腔医院牙体牙髓病科患者近8年来的变化。方法对同一位牙体牙髓病科医生2002年、2010年间接诊的患者台面记录情况进行汇总和统计描述,进行对比分析。结果第1次(2002年)诊治的患者人数和牙数分别为1 912和3 447,第2次(2010年)诊治的患者人数和牙数分别为880和1 269。两次结果相比,只有患牙的牙位构成没有变化(P>0.05),其余方面差别均有统计学意义:男性就诊比例从29.43%上升为35.46%;青少年和成年人的比例分别从12.50%和74.20%降低为8.53%和69.61%;"收入不稳定"人群和"低、无收入"人群的比例分别从8.52%和14.09%上升到26.41%和24.06%;实施"复杂治疗"者的比例从39.40%上升到44.36%;治疗后对疗效"很满意"者的比例从38.75%下降到19.56%;患者人均费用从95元升为180元,上升幅度为89.47%,低于同城居民人均可支配收入的增长幅度(209.18%);享受医保者的比例从7.9%上升至30.8%。结论 8年来,牙体牙髓病科的患者特点,除了患牙构成之外,其余方面均有变化。     

Human tooth germ stem cell response to calcium-silicate based endodontic cements

Objective

The aim of this study was to compare the cytotoxic effects of endodontic cements on human tooth germ stem cells (hTGSCs). MTA Fillapex, a mineral trioxide aggregate (MTA)-based, salicylate resin containing root canal sealer, was compared with iRoot SP, a bioceramic sealer, and AH Plus Jet, an epoxy resin-based root canal sealer.

Material and Methods

To evaluate cytotoxicity, all materials were packed into Teflon rings (4 mmµ3 mm) and co-cultured with hTGSCs with the aid of 24-well Transwell permeable supports, which had a pore size of 0.4 µm. Coverslips were coated with MTA Fillapex, iRoot SP and AH Plus Jet and each coverslip was placed onto the bottom of one well of a six-well plate for scanning electron microscopy (SEM) analysis. Before the cytotoxicity and SEM analysis, all samples were stored at 37ºC and at 95% humidity and 5% CO₂ for 24 hours to set. The cellular viability was analyzed using MTS test (3-(4,5-dimethyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium). The cytotoxic effects and SEM visualization of the tested materials were analyzed at 24-hour, 72-hour, one-week and two-week periods.

Results

On the 1^st day, only MTA Fillapex caused cytotoxicity compared to negative control (NC) group (p<0.008). No significant difference was observed between the other tested materials at this period (p>0.05). After 14 days of incubation with the test materials, MTA Fillapex exhibited significantly higher cytotoxicity compared with iRoot SP, AH Plus Jet and the NC group (P<0.008). In the SEM analysis, the highest levels of cell attachment were observed for iRoot SP and the control group. After 24 hours, MTA Fillapex reduced the number of cells attached to the surface.

Conclusions

Within the limitations of this study, sealers exerted different cytotoxic effects on hTGSCs. Although all materials have exerted cellular toxicity, iRoot SP and AH Plus Jet may promote better attachment to hTGSCs.     

Accuracy of five electronic foramen locators with different operating systems: an ex vivo study

Objective:

The aim of this study was to evaluate, ex vivo, the precision of five electronic root canal length measurement devices (ERCLMDs) with different operating systems: the Root ZX, Mini Apex Locator, Propex II, iPex, and RomiApex A-15, and the possible influence of the positioning of the instrument tips short of the apical foramen.

Material and Methods:

Forty-two mandibular bicuspids had their real canal lengths (RL) previously determined. Electronic measurements were performed 1.0 mm short of the apical foramen (-1.0), followed by measurements at the apical foramen (0.0). The data resulting from the comparison of the ERCLMD measurements and the RL were evaluated by the Wilcoxon and Friedman tests at a significance level of 5%.

Results:

Considering the measurements performed at 0.0 and -1.0, the precision rates for the ERCLMDs were: 73.5% and 47.1% (Root ZX), 73.5% and 55.9% (Mini Apex Locator), 67.6% and 41.1% (Propex II), 61.7% and 44.1% (iPex), and 79.4% and 44.1% (RomiApex A-15), respectively, considering ±0.5 mm of tolerance. Regarding the mean discrepancies, no differences were observed at 0.0; however, in the measurements at -1.0, the iPex, a multi-frequency ERCLMD, had significantly more discrepant readings short of the apical foramen than the other devices, except for the Propex II, which had intermediate results. When the ERCLMDs measurements at -1.0 were compared with those at 0.0, the Propex II, iPex and RomiApex A-15 presented significantly higher discrepancies in their readings.

Conclusions:

Under the conditions of the present study, all the ERCLMDs provided acceptable measurements at the 0.0 position. However, at the -1.0 position, the ERCLMDs had a lower precision, with statistically significant differences for the Propex II, iPex, and RomiApex A-15.     

A QUANTITATIVE ANALYSIS OF ROTARY,ULTRASONIC AND MANUAL TECHNIQUES TO TREAT PROXIMALLY FLATTENED ROOT CANALS

Objective:

The efficiency of rotary, manual and ultrasonic root canal instrumentation techniques was investigated in proximally flattened root canals.

Material and Methods:

Forty human mandibular left and right central incisors, lateral incisors and premolars were used. The pulp tissue was removed and the root canals were filled with red die. Teeth were instrumented using three techniques: (i) K3 and ProTaper rotary systems; (ii) ultrasonic crown-down technique; and (iii) progressive manual technique. Roots were bisected longitudinally in a buccolingual direction. The instrumented canal walls were digitally captured and the images obtained were analyzed using the Sigma Scan software. Canal walls were evaluated for total canal wall area versus noninstrumented area on which dye remained.

Results:

No statistically significant difference was found between the instrumentation techniques studied (p<0.05).

Conclusion:

The findings of this study showed that no instrumentation technique was 100% efficient to remove the dye.