Harnessing antimicrobial peptides in endodontics.

Endodontic therapy includes various procedures such as vital pulp therapy, root canal treatment and retreatment, surgical endodontic treatment and regenerative endodontic procedures. Disinfection and tissue repair are crucial for the success of these therapies, necessitating the development of therapeutics that can effectively target microbiota, eliminate biofilms, modulate inflammation and promote tissue repair. However, no current endodontic agents can achieve these goals. Antimicrobial peptides (AMPs), which are sequences of amino acids, have gained attention due to their unique advantages, including reduced susceptibility to drug resistance, broad-spectrum antibacterial properties and the ability to modulate the immune response of the organism effectively. This review systematically discusses the structure, mechanisms of action, novel designs and limitations of AMPs. Additionally, it highlights the efforts made by researchers to overcome peptide shortcomings and emphasizes the potential applications of AMPs in endodontic treatments.

Intracellular bacterial eradication using a novel peptide in vitro.

AIM: To determine the effect of a novel antimicrobial peptide (AMP; OP145) and cell-penetrating peptide (Octa-arginine/R8) conjugate on the killing of intracellular Enterococcus faecalis, compared to OP145 and an antibiotic combination recommended for regenerative endodontic procedures. METHODOLOGY: The biocompatible concentrations of OP145 and OP145-R8 were determined by assessing their cytotoxicity against human macrophages and red blood cells. Spatiotemporal internalization of the peptides into macrophages was investigated qualitatively and quantitatively by confocal laser scanning microscopy and flow cytometry respectively. Killing of extracellular and intracellular E. faecalis OG1RF by the peptides was determined by counting the colony-forming units (CFU). Intracellular antibacterial activity of the peptides was compared to a double antibiotic combination. Confocal microscopy was used to confirm the intracellular bacterial eradication. Significant differences between the different test groups were analysed using one-way analysis of variance. p < .05 was considered to be statistically significant. RESULTS: Peptides at a concentration of 7.5 µmol/L were chosen for subsequent experiments based on the results of the alamarBlue™ cell viability assay and haemolytic assay. OP145-R8 selectively internalized into lysosomal compartments and the cytosol of macrophages. Conjugation with R8 improved the internalization of OP145 into macrophages in a temporal manner (70.53% at 1 h to 77.13% at 2 h), while no temporal increase was observed for OP145 alone (60.53% at 1 h with no increase at 2 h). OP145-R8 demonstrated significantly greater extracellular and intracellular antibacterial activity compared to OP145 at all investigated time-points and concentrations (p < .05). OP145-R8 at 7.5 µmol/L eradicated intracellular E. faecalis after 2 h (3.5 log reduction compared to the control; p < .05), while the antibiotics could not reduce more than 0.5 log CFU compared to the control (p > .05). Confocal microscopy showed complete absence of E. faecalis within the OP145-R8 treated macrophages. CONCLUSIONS: The results of this study demonstrated that the conjugation of an AMP OP145 to a cell-penetrating peptide R8 eradicated extracellular and intracellular E. faecalis OG1RF without toxic effects on the host cells.

Effect of magnifying loupes on tooth preparation of complete coverage crown: A quantitative assessment using a digital approach.

OBJECTIVE: The purpose of this study was to evaluate the use of magnifying loupes (×2.5) on the quality of tooth preparation for complete coverage crowns; performed by predoctoral students using an objective and quantitative digital method. MATERIALS AND METHODS: Forty-two predoctoral students were randomly assigned into 2 groups to perform tooth preparation for a complete coverage crown on a mandibular first molar in a manikin, with and without the use of magnifying loupes. All preparations were digitally evaluated by PrepCheck 3.0 (Dentsply Sirona). Parameters including tooth reduction, total occlusal convergence (TOC), undercut, margin quality and surface quality were assessed. Continuous data were analysed using Paired t-tests or Wilcoxon Signed Ranks tests. Ordinal data were analysed by McNemer's tests. To further detect the majority pattern ( > 50%) in each group (with and without loupes), one-sample t-test or one-sample Wilcoxon Signed Rank test was performed. The level of significance was set at p = .001 after Bonferroni adjustments for multiple testing. RESULTS: No significant differences in the measured outcomes were found between the groups with or without the use of magnifying loupes (p > .002). The majority (>50%) of both groups had no undercuts (99.3% and 99.4% both p < .001) and the preparation type was within tolerance (81.6% and 85.3%, both p < .001) with acceptable margin (86.4% and 86.3%, both p < .001) and acceptable surface quality (99.0% and 99.1%, both p < .001). However, the majority of both groups underprepared occlusally (96.0% and 95.4%, both p < .001) and axially (65.3% and 67%, both p < .001). Only 30.0%-42.1% of the participants achieved the TOC within 0-20°. CONCLUSIONS: Within the limitations of this study, the use of magnification loupes does not appear to significantly improve the quality of tooth preparation for complete coverage crown. The TOC was also found to be overprepared and occlusally underprepared.

Small molecule based anti-virulence approaches against Candida albicans infections.

Fungi are considered "silent killers" due to the difficulty of, and delays in diagnosis of infections and lack of effective antifungals. This challenge is compounded by the fact that being eukaryotes, fungi share several similarities with human cellular targets, creating obstacles to drug discovery. Candida albicans, a ubiquitous microbe in the human body is well-known for its role as an opportunistic pathogen in immunosuppressed people. Significantly, C. albicans is resistant to all the three classes of antifungals that are currently clinically available. Over the past few years, a paradigm shift has been recommended in the management of C. albicans infections, wherein anti-virulence strategies are considered an alternative to the discovery of new antimycotics. Small molecules, with a molecular weight <900 Daltons, can easily permeate the cell membrane and modulate the signal transduction pathways to elicit desired virulence inhibitory actions against pathogens. This review dissects in-depth, the discoveries that have been made with small-molecule anti-virulence approaches to tackle C. albicans infections.

Present status and future directions: Minimally invasive root canal preparation and periradicular surgery.

Inspired by several other surgical disciplines, the quest for treating diseases through minimally invasive procedures has permeated endodontics, but not without controversy. Indeed, pulp amputation/excision and root-end resection are akin to surgical procedures elsewhere in the body and therefore, an increasing number of studies have addressed the "potential" to adopt such minimally invasive procedures in root canal treatment, with the larger goal of conserving tooth tissue for long-term survival of treated teeth. Yet, it is undeniable that this "trend" has been met with immense resistance with unclear evidence to strongly support or refute this philosophy. One may view root canal treatment as having two important procedural parts: (i) gaining access to the root canal and (ii) achieving clean root canals to remove the necrotic/infected or irreversibly inflamed tissues and then fill the space that was occupied by the pulp tissue and subsequently enlarged during cleaning and shaping, which should result in two key long-term outcomes: (i) healing of periradicular periodontitis and (ii) survival/retention of the tooth. Whilst a lot of interest has been directed towards gaining access through minimally invasive cavity designs, it is surprising that little effort has been expended on studying minimally invasive root canal preparation or surgical intervention. The aim of this review is not to promote or denigrate these philosophies, but to provide a balanced overview of the concepts, currently available evidence and future perspectives on minimally invasive endodontics from the context of root canal preparation and surgical endodontics. Specific attention is given to the role of modern irrigation strategies in potentially improving canal cleanliness even when canals are minimally prepared and the areas of research that are currently lacking in this topic.

Antibiofilm activity of phytochemicals against Enterococcus faecalis: A literature review.

Enterococcus faecalis is a leading causative pathogen of recalcitrant infections affecting heart valves, urinary tract, surgical wounds and dental root canals. Its robust biofilm formation, production of virulence factors and antibiotic resistance contribute significantly to its pathogenicity in persistent infections. The decreased effectiveness of most of antibiotics in preventing and/or eradicating E. faecalis biofilms mandates the discovery of alternative novel antibiofilm agents. Phytochemicals are potential sources of antibiofilm agents due to their antivirulence activity, diversity of chemical structure and multiple mechanisms of action. In this review, we describe the phenotypic and genetic attributes that contribute to antimicrobial tolerance of E. faecalis biofilms. We illuminate the benefits of implementing the phytochemicals to tackle microbial pathogens. Finally, we report the antibiofilm activity of phytochemicals against E. faecalis, and explain their mechanisms of action. These compounds belong to different chemical classes such as terpenes, phenylpropenes, flavonoids, curcuminoids and alkaloids. They demonstrate the ability to inhibit the formation of and/or eradicate E. faecalis biofilms. However, the exact mechanisms of action of most of these compounds are not fully understood. Therefore, the future studies should elucidate the underlying mechanisms in detail.

Impact of agitation/activation strategies on the antibiofilm potential of sodium hypochlorite/etidronate mixture in vitro.

BACKGROUND: To investigate the effect of a rotary agitation method or ultrasonically activated irrigation on the antibiofilm effect of a mixture of sodium hypochlorite (NaOCl) and etidronate (1-hydroxyethylidene-1,1-bisphosphonate, HEBP) using a dual-species biofilm model in root canal system. METHODS: Mature dual-species biofilms of Enterococcus faecalis and Streptococcus gordonii were formed in root canals of mandibular premolars. Teeth were randomly allotted (n = 12) to group 1, XP-endo Finisher (XPF); group 2, ultrasonically activated irrigation (UAI); group 3, syringe-and-needle irrigation (SNI). In all groups, canals were instrumented with a rotary instrument (XP-endo Shaper) prior to irrigant agitation/activation. A mixture containing 2.5% NaOCl and 9% HEBP was used throughout the experiment. Bacterial counts from the canal were determined using qPCR before preparation (S1), after preparation (S2), and after final irrigation agitation/activation (S3). Bacterial viability within the dentinal tubules in the coronal, middle and apical root-thirds was quantified using confocal microscopy after Live/Dead staining. The bacterial counts and viability were compared between groups using one-way ANOVA and post-hoc Tukey's tests. Paired t-test was used to compare the bacterial counts within groups. RESULTS: Instrumentation alone could significantly reduce the microbial counts in all the groups (P < 0.0001). Subsequent agitation/activation resulted in significant microbial reduction only in XPF and UAI (P < 0.05), both of which reduced significantly more microbial counts than SNI (P < 0.05). Live/Dead staining revealed that XPF and UAI showed significantly greater percentage of dead bacteria within the dentinal tubules than SNI in the coronal third (P < 0.05); UAI resulted in the significantly highest percentage of dead bacteria in the middle third (P < 0.05); while there was no significant difference between the groups in the apical third (P > 0.05). CONCLUSIONS: When using the sodium hypochlorite/etidronate mixture for irrigation, final irrigant agitation/activation with XP-endo Finisher or ultrasonic can improve disinfection of the main root canal space and the dentinal tubules in the coronal third, while ultrasonically activated irrigation appears to exhibit better disinfection within dentinal tubules in the middle third.

Exploring the anti-caries properties of baicalin against Streptococcus mutans: an in vitro study.

Plant-derived molecules are excellent alternatives to antibiotics as anti-infective agents owing to their minimal cytotoxicity. Herein, the anti-infective property of the hydroxyflavone baicalin, was investigated against biofilms of the key dental caries pathogen Streptococcus mutans. Baicalin inhibited sucrose-dependent biofilm formation at a concentration of 500 µg ml-1 without affecting bacterial growth. It significantly inhibited acid production for an extended period of 8 h. Microscopic analysis revealed a 6-fold reduction in the number of adhered cells with baicalin treatment. Transcriptomic analysis of the mid-log phase and biofilm cells showed marked downregulation of the virulence genes required for biofilm formation and acid production. This study sheds significant new light on the potential for baicalin to be developed into an anti-caries agent.

Facial protection in the era of COVID-19: A narrative review.

We live in extraordinary times, where COVID-19 pandemic has brought the whole world to a screeching halt. Tensions and contradictions that surround the pandemic ridden world include the availability, and the lack thereof, various facial protection measures to mitigate the viral spread. Here, we comprehensively explore the different types of facial protection measures, including masks, needed both for the public and the healthcare workers (HCW). We discuss the anatomy, the critical issues of disinfection and reusability of masks, the alternative equipment available for the protection of the facial region from airborne diseases, such as face shields and powered air-purifying respirators (PAPR), and the skin health impact of prolonged wearing of facial protection by HCW. Clearly, facial protection, either in the form of masks or alternates, appears to have mitigated the pandemic as seen from the minimal COVID-19 spread in countries where public mask wearing is strictly enforced. On the contrary, the healthcare systems, that appear to have been unprepared for emergencies of this nature, should be appropriately geared to handle the imbalance of supply and demand of personal protective equipment including face masks. These are two crucial lessons we can learn from this tragic experience.

Cemental tear: Literature review, proposed classification and recommendations for treatment.

Cemental tears are an important condition of relevance to Endodontics but are often overlooked. A cemental tear is the partial or complete detachment of the cementum from the cemento-dentinal junction or along the incremental line within the body of cementum. The limited attention received is most likely due to the limited awareness amongst dental professionals and challenges in accurately diagnosing them, resulting in misdiagnosis and erroneous treatment. The aim of this review is to describe the: (i) epidemiology and predisposing factors; (ii) clinical, radiographic and histological features and (iii) the clinical management and treatment outcomes of cemental tear. The review included 37 articles published in English that comprised eight observational studies and 29 case reports. The prevalence of cemental tears was reported to be lower than 2%; whilst the incidence remains unknown. Internal factors due to the inherent structural weakness of cementum and its interface with the dentine, and external factors that are associated with stress have been proposed as the two mechanisms responsible for the development and propagation of cemental tears. Predisposing factors that have been implicated were tooth type, gender, age, previous root canal treatment, history of dental trauma, occlusal trauma and excessive occlusal force; however, evidence is limited. Common clinical and radiographic manifestations of cemental tears resemble the presentations of primary endodontic diseases, primary periodontal diseases and combined endodontic-periodontal lesions. Clinical management tended to focus on complete removal of the torn fragments and periodontal treatment, often combined with regenerative treatment. In this article, a new classification for cemental tears is developed that consists of classes 0 to 6 and stages A, B, C and D based on the: (i) location and accessibility of the torn cemental fragment; (ii) the pattern and extension of the associated bony defect in relation to the root length and (iii) the number of root surface/s affected by the cemental tear/s and the associated bony defect. Recommendations for treatment strategies are also provided and linked to the classification to aid in streamlining the process of treatment decision making.

A novel three-dimensionally printed model to assess biofilm removal by ultrasonically activated irrigation.

AIM: To apply an innovative three-dimensionally printed tooth model to investigate the efficacy of three ultrasonically activated irrigation (UAI) systems in removing multispecies biofilms from dentine samples. METHODOLOGY: Three-dimensionally printed teeth with a curved root canal were fabricated with a standardized slot in the apical third of the root to achieve precision fit of human root dentine specimens. Multispecies biofilms including Enterococcus faecalis, Streptococcus mitis and Campylobacter rectus were developed in the root canal for 21 days. The canals were allocated to be irrigated with 1% sodium hypochlorite (NaOCl) using a syringe and needle or ultrasonically activated NaOCl with a stainless-steel file (Irrisafe), a conventional nickel-titanium (Ni-Ti) file (CK) or a blue heat-treated Ni-Ti file (Endosonic Blue). Infected root canals irrigated with distilled water served as controls. Bacterial reduction was determined by colony-forming unit (CFU) counting (n = 20), whilst biofilms were analysed using confocal laser scanning microscopy (n = 7) and field emission scanning electron microscopy. For CFU counting, the independent two-sample t-test (Welch's t-test) was examined to compare overall bacterial reduction amongst groups. For CLSM analysis, the data were analysed using one-way analysis of variance (ANOVA), followed by the Scheffé post hoc test. The p-values <.05 were considered to indicate statistical significance. RESULTS: All groups in which NaOCl was ultrasonically activated had significantly lower CFU values than the syringe-and-needle irrigation and control groups (p < .05). Ultrasonic activation with the stainless-steel file and blue heat-treated Ni-Ti file significantly reduced the biofilm volume compared with other groups (p < .05). Overall, UAI with the blue heat-treated file resulted in the highest antibacterial and biofilm removal efficacy. CONCLUSIONS: UAI with different inserts had differential antibiofilm effects. The blue heat-treated Ni-Ti ultrasonic insert resulted in the greatest antibacterial and biofilm removal from dentine in this standardized root canal model.

Three-dimensional qualitative and quantitative analyses of the effect of periradicular lesions on the outcome of regenerative endodontic procedures: A prospective clinical study.

OBJECTIVES: Qualitative and quantitative evaluation of the outcomes of regenerative endodontic procedure (REP) on human immature necrotic teeth with apical periodontitis using cone-beam computed tomography (CBCT) MATERIALS AND METHODS: Immature permanent teeth (n = 50) with necrotic pulp and periradicular pathosis were treated with a cell-homing concept-based REP. Following the procedure, a limited field-of-view CBCT scan was obtained. At each recall session (6, 12, 18 months), clinical tests were performed, and a digital periapical radiograph was taken. When significant radiographic changes were evident in the follow-up, a final CBCT scan was taken for qualitative and quantitative assessment. These initial and follow-up CBCT scans were assessed for quantification of changes in root length, pulp space diameter and periradicular lesion size. The data were statistically analysed using t test, one-way ANOVA, post hoc test and paired t test (P = 0.05). RESULTS: Of the teeth, 94.6% were clinically successful based on the lack or regression of signs and symptoms after 48 months follow-up. REP resulted in a statistically significant increase in root length, decrease in pulp space diameter and periradicular radiolucency (P < 0.05). CBCT images illustrated various patterns of root maturation including an increased thickening of the canal walls and continued root maturation (37.1%), continued root development with the apical foramen remaining open (57.1%), severe calcification (obliteration) of the canal space (2.9%) and hard tissue barrier formation in the canal space between the coronal plug and the root apex (2.9%). CONCLUSION: This study highlighted that the expected outcome of radiographic root development was less predictable when immature permanent teeth with periradicular pathosis were treated with REP. CLINICAL RELEVANCE: The size and extent (expansion/destruction of the cortical plate) of periradicular lesions and abscesses influence the outcome of REP. These factors must be taken into consideration during treatment planning.

Do different cone beam computed tomography exposure protocols influence subjective image quality prior to and after root canal treatment?

OBJECTIVES: The current study aimed to evaluate different CBCT exposure protocols and influencing factors affecting the subjective image quality of scans taken for endodontic indications. MATERIALS AND METHODS: Twelve extracted teeth, comprising of two sets of maxillary molars, premolars, canines and incisors, mandibular premolars, and molars, were endodontically treated, and either received a fiber or metal post. The teeth were scanned by CBCT imaging before and after root canal treatment, and after post insertion. Each scan was performed thrice, using an ultra low dose (ULD), standard (SM), and high-resolution mode (HR), respectively. Twelve observers-4 endodontists, 4 periodontists, and 4 radiologists-assessed the subjective image quality using visual analogue scales (VAS). Potential influencing factors were evaluated including acquisition mode, observer specialty, stage of treatment, type of post, and type of tooth, using one-way ANOVA and T test. RESULTS: Teeth scanned with the ULD had the highest average VAS score (72.5), followed by HR (70.2), and SM (69.0) for values pooled from all teeth and observers. CBCT acquisition mode was not a significant influencing factor on the VAS scores. Observer specialty, stage of treatment, type of post, and type of tooth were significant influencing factors. CONCLUSIONS: Based on the present in vitro data, a low-dose CBCT mode seems not to negatively affect the perception of image quality. CLINICAL RELEVANCE: The findings from this in vitro study demonstrate that a low-dose CBCT mode might have potential for diagnostics prior to or following endodontic treatment.

The Influence of Surface Roughening and Polishing on Microbial Biofilm Development on Different Ceramic Materials.

PURPOSE: To test the hypothesis that surface roughening and polishing of ceramics have no effect on their surface roughness and biofilm adhesion. MATERIALS AND METHODS: Feldspathic ceramic Vitablocks™ TriLuxe forte (VTF), lithium disilicate glass IPS e.max Press™ (IPS) and zirconia reinforced lithium silicate Vita Suprinity™ (VS) ceramic blocks (n = 27 per group) were prepared from sintered CAD blocks using a water-cooled saw. They were further subdivided into 3 subgroups according to the surface treatment protocols (n = 9): as prepared, roughened and polished. The surface roughness of the ceramic blocks was measured using an electro-mechanical profilometer. The ceramic sections were inoculated with Streptococcus mutans and incubated for 48 hours to form a biofilm. The ceramic surfaces with the biofilms were analyzed using Confocal Laser Scanning Microscopy to calculate the percentage of live bacteria and substratum coverage by the biofilm, and further visualized using scanning electron microscopy. Statistical analysis was done with SPSS software using two-way ANOVA, followed by post hoc Bonferroni test to identify significant differences between the groups. The level of significance was set at p = 0.05. RESULTS: As prepared VTF showed significantly higher mean surface roughness values than as prepared IPS and VS. The mean percentage of live bacteria and biofilm coverage of the substrate were significantly higher in the roughened ceramic blocks than the as prepared and polished blocks for all three ceramic types (p < 0.05). Polished specimens of VS significantly lower percentage of biofilm coverage than the other groups (p < 0.05). CONCLUSIONS: This study sheds new light that adjustments of ceramic restorations prior to cementation increases the likelihood for formation and adhesion of microbial biofilms on the surface. Polished zirconia reinforced lithium disilicate ceramics demonstrated the lowest bacterial adhesion among the evaluated ceramics.

Guardian genes ensuring subsistence of oral Streptococcus mutans.

Despite the substantial research advancements on oral diseases, dental caries remains a major healthcare burden. A disease of microbial dysbiosis, dental caries is characterised by the formation of biofilms that assist demineralisation and destruction of the dental hard tissues. While it is well understood that this is a multi-kingdom biofilm-mediated disease, it has been elucidated that acid producing and acid tolerant bacteria play pioneering roles in the process. Specifically, Streptococcus mutans houses major virulence pathways that enable it to thrive in the oral cavity and cause caries. This pathogen adheres to the tooth substrate, forms biofilms, resists external stress, produces acids, kills closely related species, and survives the acid as well as the host clearance mechanisms. For an organism to be able to confer such virulence, it requires a large and complex gene network which synergise to establish disease. In this review, we have charted how these multi-faceted genes control several caries-related functions of Streptococcus mutans. In a futuristic thinking approach, we also briefly discuss the potential roles of omics and machine learning, to ease the study of non-functional genes that may play a major role and enable the integration of experimental data.

Trans-cinnamaldehyde potently kills Enterococcus faecalis biofilm cells and prevents biofilm recovery.

Enterococcus faecalis is a biofilm-forming, nosocomial pathogen that is frequently isolated from failed root canal treatments. Contemporary root canal disinfectants are ineffective in eliminating these biofilms and preventing reinfection. As a result, there is a pressing need to identify novel and safe antibiofilm molecules. The effect of short-term (5 and 15 min) and long-term (24 h) treatments of trans-cinnamaldehyde (TC) on the viability of E. faecalis biofilms was compared with currently used root canal disinfectants. Treatment for 15 min with TC reduced biofilm metabolic activity as effective as 1% sodium hypochlorite and 2% chlorhexidine. Treatment with TC for 24 h was significantly more effective than 2% chlorhexidine in reducing the viable cell counts of biofilms. This serendipitous effect of TC was sustained for 10 days under growth-favoring conditions. For the first time, our study highlights the strong antibacterial activity of TC against E. faecalis biofilms, and notably, its ability to prevent biofilm recovery after treatment.

A chitosan-based irrigant improves the dislocation resistance of a mineral trioxide aggregate-resin hybrid root canal sealer.

OBJECTIVES: To investigate the effectiveness of root canal irrigation with chitosan on the dislocation resistance of a root canal sealer (MTA Fillapex) in vitro, measured by the push-out bond strength test. MATERIALS AND METHODS: Root canals of mandibular premolars (n = 57) were prepared using rotary files with 5.25% sodium hypochlorite as the irrigant during instrumentation. Following this, the specimens were randomly divided into three groups (n = 19) based on the final irrigant: group 1, 0.2% chitosan solution; group 2, 17% EDTA solution; group 3, saline. Three specimens from each group were analyzed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The remaining specimens of each group were divided into two subgroups (n = 8) based on the method of agitation of the final irrigants (chitosan/EDTA/saline): subgroup A, sonic (Endoactivator, Dentsply Maillefer); subgroup B, no activation (control). After irrigation, all specimens obturated with a commercial mineral trioxide aggregate-resin hybrid sealer (MTA Fillapex, Angelus, Londrina, Brazil). Dislocation resistance was measured using the push-out bond strength test after 3 weeks. The data were analyzed using Kruskal-Wallis test (P = 0.05). RESULTS: Immaterial of the irrigant agitation, groups irrigated with chitosan showed significantly higher bond strength values than those irrigated with EDTA (P < 0.05). Groups irrigated with saline showed the least bond strength values (P < 0.05). When EDTA was used, sonic agitation significantly improved the bond strength of the sealer, compared to the control (P < 0.05). There was no significant difference between sonic agitation and the control when chitosan solution was used as the final irrigant (P > 0.05). The nitrogen/carbon ratio was significantly higher in chitosan groups compared to the control group (P < 0.05). CONCLUSION: This study provides the first evidence that chitosan irrigation improves the dislocation resistance of MTA-resin hybrid root canal sealer, compared to EDTA and saline irrigation. CLINICAL RELEVANCE: Chitosan-based irrigation has been previously shown to demonstrate anti-biofilm properties in the root canal. The present study demonstrates that chitosan can improve the bond strength of a root filling material, which may contribute to better sealing of the root canal system.

Oral health-related quality of life (OHRQoL) before and after endodontic treatment: a systematic review.

OBJECTIVES: This systematic review was undertaken to determine the oral health-related quality of life (OHRQoL) before and after endodontic treatment. MATERIALS AND METHODS: Based on the PRISMA guidelines, electronic databases (n = 7) were searched and from 1038 citations, 16 papers were included in this review. Information on study design, sample size, intervention/treatment modality, methods of assessing OHRQoL, and the key findings were extracted and analyzed. RESULTS: Among the 16 studies, 3 were cross-sectional surveys, 9 were longitudinal studies, and 4 were randomized clinical trials. The cross-sectional studies reported improvements in OHRQoL following root canal treatment. Comparative longitudinal studies did not identify a significant association between improvements in OHRQoL and the method of root canal instrumentation or number of instruments used. Clinical trials found that improvements in OHRQoL were significantly associated with instrumentation technique, surgical-incision approach, and the application of platelet-concentrate during surgery. Several methods of assessing OHRQoL were employed with the most common being the Oral Health Impact Profile (OHIP), albeit using different versions. CONCLUSIONS: The results of this systematic review indicate that the QoL of patients improved after endodontic treatment. Nevertheless, these results are limited to patients who seek endodontic treatment and cannot be generalized. The lack of well-designed observational studies with standardized assessment approaches, coupled with heterogeneity of study design and interventions, precluded quantitative synthesis. CLINICAL RELEVANCE: Pragmatic clinical trials are more meaningful to understand patient-centered outcomes of treatment. This review shows that endodontic treatment does improve the QoL. However, future studies should use standardized tools and data reporting, which are critical to make meta-analyses possible.

Root fillings with a matched-taper single cone and two calcium silicate-based sealers: an analysis of voids using micro-computed tomography.

OBJECTIVES: To compare the percentage of voids in matched-taper single-cone fillings with GuttaFlow Bioseal or BioRoot RCS root canal sealers, using micro-computed tomography. MATERIALS AND METHODS: Forty-eight single-rooted mandibular premolars were prepared using rotary files and randomly allocated into 2 groups (n = 24), wherein the canals were filled with a matched-taper single gutta-percha cone and one of the two sealers: Group 1, GuttaFlow Bioseal and Group 2, BioRoot RCS. The specimens were scanned with micro-CT before and after root canal filling. A specialized software was used to calculate the voids volume percentage (V%) in the filling for the whole root canal, root canal thirds, and the last millimeter from the apex. Data were statistically analyzed by ANOVA and Tukey tests (p < 0.05). RESULTS: Root canals filled with GuttaFlow Bioseal had significantly less V% than those filled with BioRoot RCS in all the root-thirds (p < 0.05) except at the apical 1 mm (p > 0.05). Comparing the root-thirds, GuttaFlow Bioseal showed similar V% in all regions (p > 0.05), while BioRoot RCS group had significantly greater V% in the coronal third compared with the other thirds (p < 0.05). CONCLUSIONS: Root canals filled with a matched-taper single cone and GuttaFlow Bioseal had significant less voids than those with BioRoot RCS, except at the apical 1 mm. CLINICAL RELEVANCE: Voids in root fillings have been reported to have a negative impact on root canal treatment. This study highlights the percentage of voids in root fillings composed of a single cone of gutta-percha with two types of calcium silicate-based bioceramic sealers.

'Evaluation of the introduction of a dental virtual simulator on the performance of undergraduate dental students in the pre-clinical operative dentistry course'.

INTRODUCTION: Virtual reality-based platforms are becoming increasingly popular in education. The aim of this study was to evaluate the performance of undergraduate dental students with the introduction of the Moog Simodont dental trainer (VR) within the pre-clinical curriculum in the direct restoration module of the operative dentistry course using manual and digital methods. METHODS: Thirty-two randomly selected year 2 undergraduate students were divided into two groups: group 1, exposed to the Moog Simodont dental trainer (VR) and group 2, no exposure to VR. All students were then evaluated in carrying out a Class I preparation in a single-blinded fashion. All preparations were evaluated by three assessors using a traditional manual approach and a digital software. Statistical analysis of the data was performed using chi-square test (alpha = 0.05). RESULTS: The number of students who performed satisfactory preparations was more in group 1 (12/16), compared to group 2 (7/16). The percentage of satisfactory domains was significantly higher in group 1, compared to group 2, both in the manual evaluation (83.9% (94/112) and 59.8% (67/112) in groups 1 and 2, respectively) and in the digital evaluation (85.7% (96/112) and 55.4% (62/112) in groups 1 and 2, respectively) (P < .05). There was no significant difference between the manual and digital methods of evaluation with regard to the percentage of satisfactory or unsatisfactory preparations (P > .05). CONCLUSIONS: The use of the Moog Simodont dental trainer (VR) significantly improved the satisfactory performance of students. The virtual reality simulator may be a valuable adjunct in the undergraduate direct restorations course and for remedial student.