Self-efficacy of undergraduate dental students in Endodontics within Aarhus and Amsterdam.

AIM: To understand whether the self-efficacy of undergraduates is associated with the extent of the endodontic education they received. METHODOLOGY: Data were obtained from three undergraduate endodontic programmes in two universities: Aarhus University (AU), Denmark and the Academic Centre for Dentistry Amsterdam (ACTA), the Netherlands. Just before their graduations in 2016 or 2017, students completed a questionnaire that contained the Endodontic General Self-Efficacy Scale and questions on how they valued the education they received in Endodontics. The information on the number and type of root canal treatments participants had performed on patients was collected from dental clinic management systems. Data were ana-lysed using non-parametric tests and multiple regression analyses. RESULTS: The median number of treated root canals on patients per student was 5 in the standard programme at ACTA, 10 in AU, and 14.5 in the extended programme at ACTA. Students' self-efficacy increased with the number of treated root canals; however, retreatments and root canal treatments in molars were negatively associated with self-efficacy. All students wanted more experience in performing root canal treatment on patients. CONCLUSIONS: The endodontic self-efficacy of students from the standard programmes of the two participating universities was comparable. Students' self-efficacy was influenced mostly by their clinical experience when performing root canal treatment. It seems that the more root canal treatments students perform on patients, the greater their self-efficacy is at graduation. However, treating difficult cases (molars and retreatments) might reduce their self-efficacy.

Method of teaching undergraduate students to perform root canal treatment: It's influence on the quality of root fillings.

INTRODUCTION: This study aimed to assess whether the method of teaching endodontology influenced the quality of root fillings made by undergraduate students. MATERIALS AND METHODS: The method of teaching endodontology at our institution was revised. Changes concerned: the programme (ie method of clinical training and summative assessment), and the supervision whilst performing root canal treatment on patients. An intermediate cohort (N=91) comprised partly students attending the former programme (involving patients) and partly students attending the revised programme (without patients). After succeeding in the summative assessment, the quality of the first root filling made by the student in a patient under supervision of either a general dental practitioner or an endodontist was evaluated according to pre-determined criteria. Data were analysed using Cohen's Kappa, Chi-square, Fisher's exact, Mann-Whitney and Kruskal-Wallis tests. RESULTS: Sixty-two per cent (47 of 76) of root fillings made by students who attended the revised programme were of good quality, in comparison with 47% (seven of 15) of those made by students who attended the former programme (P=.274). Less complex treatments had better quality root fillings if students were supervised by endodontists (88% (14 of 16) good quality) than supervised by general dental practitioners (59% (22 of 37) good quality) (P=.045). Complex treatments did not differ in quality of root fillings for the supervision types (P=.825). CONCLUSION: The quality of root fillings made by students who attended the revised programme seems at least as high as that of those who attended the former programme. Higher quality root fillings might be obtained under supervision of endodontists than under supervision of general dental practitioners.

Definitions and Epidemiology of Endodontic Infections.

PURPOSE OF REVIEW: This review describes the recent findings from epidemiological studies on endodontic infections. The recent literature was screened for studies on the prevalence of primary apical periodontitis and posttreatment apical periodontitis in various populations. RECENT FINDINGS: Twenty-nine articles reporting data on the prevalence of primary or posttreatment apical periodontitis from all over the world were included. The prevalence of apical periodontitis varied between 7 and 86%, while that of posttreatment apical periodontitis varied between 10 and 62%. The quality of the coronal restoration and the root filling appears to be the major predictors of apical periodontitis. SUMMARY: The recent findings from epidemiological studies on the prevalence of primary and posttreatment apical periodontitis in various populations are not substantially different from those from earlier years. It appears that the health of periapical tissues has not majorly improved in the general population.

Prevalence and nature of fungi in root canal infections: a systematic review and meta-analysis.

The role of bacteria in causing apical periodontitis has been widely established, whilst the role of other microorganisms is studied less thoroughly. This systematic review and meta-analysis reviewed the literature for the prevalence and diversity of fungi in root canal infections. An extensive literature search was carried out in the Cochrane databases, EMBASE, MEDLINE, LILACS, SciELO and Web of Science. Additional studies were identified from six endodontic journals, four main endodontic textbooks and references of relevant papers. Selected clinical studies included sampling of necrotic pulps in permanent teeth and microbial analysis of these samples. Studies were critically appraised using the Joanna Briggs Institute Prevalence Critical Appraisal Checklist. Meta-analysis was performed using MetaXL. The screening of 1041 titles and abstracts and full-text reading yielded 54 studies. The overall prevalence of fungi in root canal infections was 7.5% (CI 95%: 3.6-11.8%) in the inverse variance fixed effect heterogeneity model. Candida albicans was the most frequently isolated species. Significant heterogeneity was observed (P < 0.001, I2  = 85.04%). Subgroup analyses based on geographical location, period of publication, type of infection, state of general health, communication with the oral cavity, type of sample and identification method revealed no factor influencing the prevalence. Better standardized techniques and a comprehensive analysis will reveal a more detailed and accurate representation of the prevalence and nature of fungi in root canal infections.

Sealing efficacy of a single-cone root filling after post space preparation.

OBJECTIVES: The aim of the present study was to compare the sealing efficacy of root fillings made by a single-cone technique with three different sealers and a cold lateral compaction technique with an epoxy sealer. MATERIALS AND METHODS: Eighty extracted single-rooted human teeth were assigned to four experimental groups: group 1, single-cone and epoxy sealer; group 2, single-cone and calcium silicate-based sealer; group 3, single-cone and methacrylate resin-based sealer; and group 4, cold lateral compaction and epoxy sealer. Twenty extra teeth served as negative and positive controls. After preparation of a coronal post space, the sealing efficacy of the root fillings was assessed on a fluid transport setup. The results were analyzed using Kruskal-Wallis and Mann-Whitney U test. RESULTS: No fluid transport was detected for the negative controls whereas all the positive controls showed rapid fluid transport. No significant difference was detected between groups 1, 3, and 4 whereas group 2 demonstrated significantly more fluid transport than all the other experimental groups. CONCLUSIONS: Root fillings made by a single-cone technique with the epoxy or methacrylate-based sealers were as effective after post space preparation as those made by a cold lateral technique with the epoxy sealer in sealing the root canal. CLINICAL RELEVANCE: Specific root canal sealers in combination with single-cone technique represent a noteworthy alternative to the use of cold lateral compaction technique when a post space is required. The use of effective endodontic procedures with simplified technical implementation may positively affect endodontic outcome.

[Endodontics in motion: new concepts, materials and techniques 2. The use of cone-beam computed tomography in endodontic diagnosis and treatment planning]. / Endodontologie in beweging: nieuwe concepten, materialen en technieken 2. Conebeamcomputertomografie in de endodontische diagnostiek en behandelplanning.

Systems for cone-beam computed tomography make a high-quality 3D reconstruction of dentomaxillofacial structures possible, without exposing the patient to excessive doses of radiation. Due to its 3D nature cone-beam computed tomography is superior to conventional dental radiographic imaging methods for many aspects of endodontic diagnosis and treatment planning. There are multiple indications for the use of cone-beam computed tomography scans in endodontics, including detection of periapical lesions or root fractures and the exploration of the root canal anatomy and its deviations. Depending on conditions, a judicious decision will always have to be made with regard to the radiographic technique to be applied. Primary in that respect must be the means by which the most accurate diagnostic image can be achieved with the lowest possible dose of radiation. Making a cone-beam computed tomography scan is justified only when the required diagnostic information cannot be achieved adequately using lower dose conventional dental radiographic imaging techniques.

Improving the accuracy of a fluid transport method.

AIM: To compare the sealing ability of the same root fillings when measured by a conventional fluid transport method that uses water or by a modified fluid transport method that uses a wetting fluid as tracer. METHODOLOGY: The amount of fluid transport along the same root fillings (AH26, cold lateral compaction of gutta-percha) was measured in a cross-over design in fluid transport set-ups using either water or a wetting fluid as tracer. RESULTS: A Wilcoxon signed-rank test revealed a significant difference in the amount of fluid transport measured along the same root fillings by the two fluid transport methods (P = 0.013). The fluid transport method using wetting fluid detected a significantly higher percentage of root fillings with fluid transport (P = 0.021). CONCLUSIONS: Fluid transport using a wetting fluid as a tracer was more sensitive in the assessment of sealing ability of root fillings than the conventional fluid transport method using water.

Ecology of the microbiome of the infected root canal system: a comparison between apical and coronal root segments.

AIM: To evaluate the microbial ecology of the coronal and apical segments of infected root canal systems using a complete sampling technique and next-generation sequencing. METHODOLOGY: The roots of 23 extracted teeth with apical periodontitis were sectioned in half, horizontally, and cryo-pulverized. Bacterial communities were profiled using tagged 454 pyrosequencing of the 16S rDNA hypervariable V5-V6 region. RESULTS: The sequences were classified into 606 taxa (species or higher taxon), representing 24 bacterial phyla or candidate divisions and one archaeal phylum. Proteobacteria were more abundant in the apical samples (P < 0.05), whilst Actinobacteria were in significantly higher proportions in the coronal samples. The apical samples harboured statistically significantly more taxa than the coronal samples (P = 0.01) and showed a higher microbial diversity. Several taxa belonging to fastidious obligate anaerobes were significantly more abundant in the apical segments of the roots compared with their coronal counterparts. CONCLUSIONS: Endodontic infections are more complex than reported previously. The apical part of the root canal system drives the selection of a more diverse and more anaerobic community than the coronal part. The presence of a distinct ecological niche in the apical region explains the difficulty of eradication of the infection and emphasizes the need for new treatment approaches to be developed.

The effects of hyperosmosis or high pH on a dual-species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa: an in vitro study.

AIM: To investigate the effect of hyperosmotic hyperosmosis or alkaline stress on a dual-species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa. METHODOLOGY: Biofilms were grown on glass cover slips suspended in bacterial inoculate for 96 h, after which the cover slips with attached biofilms were immersed in brain heart infusion broth (BHI-broth) with 6 mol L(-1) sodium chloride (NaCl) representing the hyperosmotic group or Ca(OH)(2), pH 12.1, representing the alkaline group. Two per cent sodium hypochlorite and BHI- broth served as positive and negative controls, respectively. After treatment, the biofilms were washed, harvested and plated on blood-agar plates after serial dilution. The bactericidal effect was assessed by determining the colony-forming units (CFU). The effect on the biofilm mass was imaged with confocal laser scanning microscopy (CLSM). RESULTS: Hyperosmosis reduced the CFU of both species significantly after 72 h (P < 0.0001). After 168 h, P. aeruginosa was eradicated and the E. faecalis reduction was more than 99%. High pH could not induce a significant bacterial reduction. CLSM revealed dense flocculation of the biofilms incubated in alkaline broth. CONCLUSION: Hyperosmosis effectively reduced a dual-species biofilm of E. faecalis and P. aeruginosa, whilst high pH had limited bactericidal effect in this model.

Effect of dentinal fluid composition on dentin demineralization in vitro.

Dentin demineralization is reduced by perfusion with water. We hypothesized that a simulated dentinal fluid (SDF) that contains albumin, in addition to electrolytes, would be more effective in reducing dentin demineralization than water alone, and this effect would increase with increasing flow rate of SDF. Perfusion rate in tooth segments that carried buccal cervical dentin windows was measured in a fluid transport set-up. These windows were then demineralized under perfusion with water, or SDF at 1.47 kPa for 31 days. We analyzed integrated mineral loss and lesion depth with the use of transverse microradiography (TMR), which revealed that 38% more mineral dissolved from dentin lesions perfused with water than from those perfused with SDF. The former were also 18% deeper. Flow rate of dentinal fluid showed no correlation with demineralization. We concluded that composition of dentinal fluid is an important determinant of the rate of lesion formation and progression in dentin.

Comparison of the in vitro permeability of human dentine according to the dentinal region and the composition of the simulated dentinal fluid.

OBJECTIVE: To compare the permeability of the occlusal and the cervical dentinal regions within the same tooth, which represent the bottom of Class I and V cavities, respectively, with two different compositions of perfusion fluid, in vitro. METHODS: An occlusal and a buccal disc were cut from each extracted third molar at a level close to the pulp chamber. The convective permeability of the discs was measured in a fluid transport model using de-ionised water or 1:3 diluted bovine serum and the hydraulic conductance was determined. RESULTS: The mean hydraulic conductance values of the occlusal and the buccal cervical human dentine to water were 0.069 and 0.047 microl min(-1) cm(-2) cm H(2)O(-1), respectively. When diluted bovine serum was used, the corresponding values were 0.036 and 0.012 microl min(-1) cm(-2) cm H(2)O(-1), respectively. Statistical analysis revealed no significant difference between the permeability of these two regions. The composition of the perfusion fluid significantly influenced the permeability of dentine. CONCLUSIONS: The occlusal and the buccal cervical regions of human dentine have similar permeability characteristics in vitro. There is a strong reverse correlation between the viscosity of the perfusion fluid and the perfusion through the dentine.

Effect of perfusion with water on demineralization of human dentin in vitro.

Dentinal fluid rarely features in caries studies of dentin. The mutual effects of in vitro perfusion and dentin demineralization were investigated. The correlation between the remaining dentin thickness and demineralization was also analyzed. Buccal cervical dentin windows in human tooth segments were demineralized either with or without perfusion with water at 3.14 kPa. Transverse microradiography revealed that dentin perfusion reduced the amount of mineral loss from the lesions by 22 vol%; the reduction in lesion depth was 8%. Perfusion rate, which was measured throughout the demineralization process by means of a fluid transport model, did not change significantly. Lesions formed closer to the pulp exhibited increased mineral loss and lesion depth. In conclusion, dentinal fluid flow offers some protection against demineralization. For a better approximation of clinical reality, therefore, in vitro studies on dentinal caries should consider the effect of dentinal fluid flow.

The effects of post-extraction time on the hydraulic conductance of human dentine in vitro.

The permeability characteristics of dentine have been used in many in vitro studies to evaluate longitudinally the efficacy of various restorative and preventative procedures. However, the permeability of human dentine increases over time after tooth extraction. The aim here was to determine if there is a steady phase in dentine permeability in vitro over time. The convective permeability of dentine discs cut from extracted human third molars to 0.8% albumin solution was measured initially on day 7 after extraction using a fluid-transport model and the hydraulic conductance was calculated. The permeability of each disc was then re-measured de- and re-mounting the split-chamber 1h after the initial measurement as well as on days 8, 9, and 37 after extraction. No significant difference was found between the initial and 1h hydraulic conductances. A significant increase in hydraulic conductance was seen from day 7 to 9, but there was no significant difference between the hydraulic conductances on days 9 and 37. These results suggest that the measurements were reproducible and that a steady phase of dentine permeability is established 9 days after extraction under these study conditions in vitro.

The influence of resin composite and bonded amalgam restorations on dentine permeability in Class II cavities in vitro.

OBJECTIVES: This study was conducted to measure and compare dentine permeability reduction in Class II preparations, after restoration with resin composite or bonded amalgam, using either a multi-step or one-bottle dental adhesive system. METHODS: An in vitro fluid transport model was used to measure initial dentine permeability in Class II cavities with an intact smear layer in crown segments from extracted human premolars. One week and 3 months after restoration with resin composite or bonded amalgam, using either multi-step or one-bottle dental adhesive system, the measurements were repeated and the reduction in permeability was calculated as a percentage of the initial values. The data were analyzed statistically using a one-way ANOVA and Least Significant Difference tests. RESULTS: After 1 week the resin composite with one-bottle dental adhesive system provided the highest reduction in dentine permeability, whereas after 3 months the bonded amalgam caused the highest reduction. At both time intervals the resin composite with multi-step adhesive system provided the lowest reduction. (P=0.036 at 1 week, P=0.016 at 3 months). After 3-months storage in water a significant increase in dentine permeability reduction was found in the bonded amalgam group only (P=0.017). The reduction in dentine permeability provided by resin composite with one-bottle dental adhesive system and bonded amalgam in Class II cavities was similar at both time intervals. (P=0.182 at 1 week, P=0.750 at 3 months). SIGNIFICANCE: The results of this study indicated that on the basis of reducing dentine permeability in vitro, resin composite restorations with the investigated one-bottle adhesive system was superior to its multi-step equivalent and bonded amalgam can also be preferred in Class II restorations.

Sealer distribution in root canals obturated by three techniques.

AIM: The aim of this study was to observe sealer distribution in root canals filled by different root filling techniques. METHODOLOGY: AH26 (0.05 mL) dyed with carbon black powder was placed into the prepared root canals of maxillary central incisors using a lentulo spiral. Thereafter the canals were obturated using three different gutta-percha root-filling techniques. Horizontal sections were cut in the apical and middle portions of the filled canals. Images of the cross sections were scanned and the percentage of sealer coated canal perimeter (PSCP) was measured using a computer digital imaging system. RESULTS: At 3 mm from the apex, the PSCP after lateral condensation was similar to that after vertical condensation (P > 0.05). At 6 mm from the apex, however, the PSCP was significantly higher after lateral condensation than after vertical condensation (P < 0.05). At both levels the PSCP was significantly higher after single cone (no condensation) than after the other two condensation techniques (P < 0.0001). CONCLUSIONS: Sealer may be removed from the canal wall by the condensation procedures.